Permafrost Monthly Alerts (PMAs)

15115150 Brown, Dana R. N. (University of Alaska, Fairbanks, Department of Biology and Wildlife, Fairbanks, AK); Jorgenson, M. Torre; Douglas, Thomas A.; Romanovsky, Vladimir E.; Kielland, Knut; Hiemstra, Christopher; Euskirchen, Eugenie S. and Ruess, Roger W. Interactive effects of wildfire and climate on permafrost degradation in Alaskan lowland forests: Journal of Geophysical Research: Biogeosciences, 120(8), p. 1619-1637, illus. incl. 1 table, sketch maps, 65 ref., August 2015.

We examined the effects of fire disturbance on permafrost degradation and thaw settlement across a series of wildfires (from ~1930 to 2010) in the forested areas of collapse-scar bog complexes in the Tanana Flats lowland of interior Alaska. Field measurements were combined with numerical modeling of soil thermal dynamics to assess the roles of fire severity and climate history in postfire permafrost dynamics. Field-based calculations of potential thaw settlement following the loss of remaining ice-rich permafrost averaged 0.6 m. This subsidence would cause the surface elevations of forests to drop on average 0.1 m below the surface water level of adjacent collapse-scar features. Up to 0.5 m of thaw settlement was documented after recent fires, causing water impoundment and further thawing along forest margins. Substantial heterogeneity in soil properties (organic layer thickness, texture, moisture, and ice content) was attributed to differing site histories, which resulted in distinct soil thermal regimes by soil type. Model simulations showed increasing vulnerability of permafrost to deep thawing and thaw settlement with increased fire severity (i.e., reduced organic layer thickness). However, the thresholds of fire severity that triggered permafrost destabilization varied temporally in response to climate. Simulated permafrost dynamics underscore the importance of multiyear to multidecadal fluctuations in air temperature and snow depth in mediating the effects of fire on permafrost. Our results suggest that permafrost is becoming increasingly vulnerable to substantial thaw and collapse after moderate to high-severity fire, and the ability of permafrost to recover is diminishing as the climate continues to warm. Abstract Copyright (2015), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/2015JG003033

15120978 Natali, Susan M. (Woods Hole Research Center, Falmouth, MA); Schuur, Edward A. G.; Mauritz, Marguerite; Schade, John D.; Celis, Gerardo; Crummer, Kathryn G.; Johnston, Catherine; Krapek, John; Pegoraro, Elaine; Salmon, Verity G. and Webb, Elizabeth E. Permafrost thaw and soil moisture driving CO₂ and CH₄ release from upland tundra: Journal of Geophysical Research: Biogeosciences, 120(3), p. 525-537, illus. incl. 1 table, 69 ref., March 2015.

As permafrost degrades, the amount of organic soil carbon (C) that thaws during the growing season will increase, but decomposition may be limited by saturated soil conditions common in high-latitude ecosystems. However, in some areas, soil drying is expected to accompany permafrost thaw as a result of increased water drainage, which may enhance C release to the atmosphere. We examined the effects of ecosystem warming, permafrost thaw, and soil moisture changes on C balance in an upland tundra ecosystem. This study was conducted at a water table drawdown experiment, established in 2011 and located within the Carbon in Permafrost Experimental Heating Research project, an ecosystem warming and permafrost thawing experiment in Alaska. Warming and drying increased cumulative growing season ecosystem respiration by ~20% over 3 years of this experiment. Warming caused an almost twofold increase in decomposition of a common substrate in surface soil (0-10 cm) across all years, and drying caused a twofold increase in decomposition (0-20 cm) relative to control after 3 years of drying. Decomposition of older C increased in the dried and in the combined warmed + dried plots based on soil pore space ¹⁴CO₂. Although upland tundra systems have been considered CH₄ sinks, warming and ground thaw significantly increased CH₄ emission rates. Water table depth was positively correlated with monthly respiration and negatively correlated with CH₄ emission rates. These results demonstrate that warming and drying may increase loss of old permafrost C from tundra ecosystems, but the form and magnitude of C released to the atmosphere will be driven by changes in soil moisture. Abstract Copyright (2015), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/2014JG002872

15118351 Jantze, E. J. (Stockholm University, Department of Physical Geography and Quaternary Geology, Stockholm, Sweden); Lyon, S. W. and Destouni, G. Subsurface release and transport of dissolved carbon in a discontinuous permafrost region: Hydrology and Earth System Sciences (HESS), 17(10), p. 3827-3839, illus. incl. 1 table, sketch map, 61 ref., 2013. Includes appendices.

Subsurface hydrological flow pathways and advection rates through the landscape affect the quantity and timing of hydrological transport of dissolved carbon. This study investigates hydrological carbon transport through the subsurface to streams and how it is affected by the distribution of subsurface hydrological pathways and travel times through the landscape. We develop a consistent mechanistic, pathway- and travel time-based modeling approach for release and transport of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC). The model implications are tested against observations in the subarctic Abiskojokken catchment in northernmost Sweden (68°21' N, 18°49' E) as a field case example of a discontinuous permafrost region. The results show: (a) For DOC, both concentration and load are essentially flow-independent because their dynamics are instead dominated by the annual renewal and depletion. Specifically, the flow independence is the result of the small characteristic DOC respiration-dissolution time scale, in the range of 1 yr, relative to the average travel time of water through the subsurface to the stream. (b) For DIC, the load is highly flow-dependent due to the large characteristic weathering-dissolution time, much larger than 1 yr, relative to the average subsurface water travel time to the stream. This rate relation keeps the DIC concentration essentially flow-independent, and thereby less fluctuating in time than the DIC load.

DOI: 10.5194/hess-17-3827-2013

15115234 Marszalek, Henryk (Uniwersytet Wroclawski, Instytut Nauk Geologicznych, Zaklad Hydrogeologii Stosowanej, Wroclaw, Poland) and Wasik, Miroslaw. Some physico-chemical features of water in suprapermafrost zone in the Hornsund region (SW Spitsbergen): in Wspolczesne problemy hydrogeologii (Krogulec, Ewa, editor; et al.), Biuletyn Panstwowego Instytutu Geologicznego. Hydrogeologia, 456(2), p. 397-404 (Polish sum.), illus. incl. 1 table, 12 ref., 2013.

The hydrogeochemical background of electrolytical conductivity (36-188 mS/cm) and pH (from 6.23 to 7.35) of groundwater in the active layer of permafrost in the Hornsund region (SW Spitsbergen) was determined based on data collected in the summer season of 2005. The shallow zone of water circulation (supramermafrost zone) in Arctic regions results during intensive melting of snow, glaciers and the top layer of permafrost during short Arctic summer periods. Water was sampled from ephemeral springs that occur at the foot of mountain range slopes in the marginal zone of coastal lowlands of the Greenland Sea. Anomalous zones, outside the ranges of maximum EC and pH, mainly coincide with the occurrence of bird colonies.

URL: http://9070.indexcopernicus.com/fulltxt.php?ICID=1113871

15119006 Karlsson, Johanna Mard (Stockholm University, Department of Physical Geography, Stockholm, Sweden); Jaramillo, Fernando and Destouni, Georgia. Hydro-climatic and lake change patterns in Arctic permafrost and non-permafrost areas: Journal of Hydrology, 529, p. 134-145, illus. incl. 2 tables, sketch maps, 44 ref., October 2015.

This paper investigates patterns of lake-area and hydro-climatic change in Arctic river basins, and possible influence of permafrost change reflected in such patterns. A salient change pattern, emerging across all investigated basins in both permafrost and non-permafrost areas, is an opposite change direction in runoff (R) from that in precipitation (P). To explain this change contrast, an increase (decrease) in relative water-balance constrained evapotranspiration ET_wb /P is required where R decreases (increases). Increasing temporal variability of daily river discharge (sdQ) is found in all basins with spatially extensive lake decrease, which also exhibit decrease in ET_wb /P. Clear indication of basin-wide permafrost thaw is found in only one basin, and is possible in two more, but unlikely in the largest of the total four investigated permafrost basins. Abstract Copyright (2015) Elsevier, B.V.

DOI: 10.1016/j.jhydrol.2015.07.005

15116256 Koch, J. C. (U. S. Geological Survey, Anchorage, AK); Runkel, R. L.; Striegl, R. and McKnight, D. M. Hydrologic controls on the transport and cycling of carbon and nitrogen in a boreal catchment underlain by continuous permafrost: Journal of Geophysical Research: Biogeosciences, 118(2), p. 698-712, illus. incl. 5 tables, sketch map, 55 ref., June 2013.

Boreal ecosystems represent a large carbon (C) reservoir and a substantial source of greenhouse gases. Hydrologic conditions dictate whether C leached from boreal soils is processed in catchments or flushed to less productive environments via the stream. This study quantified hydrologic and biogeochemical C loss from a boreal catchment underlain by frozen silt, where flowpaths may deepen as the active layer thaws over the summer. We hypothesized a decrease in the magnitude of C mineralization over the summer associated with changing flowpaths and decreasing hydrologic connectivity, organic matter lability, and nitrogen (N) availability. Conservative tracers were used to partition C and N loss between catchment export and biogeochemical processing. Coupling tracers with tributary and porewater chemistry indicated C and N cycling in soil flowpaths, with an exponential decrease over the summer. Nitrate was primarily reduced in hillslope flowpaths and the lack of N reaching the stream appeared to limit C mineralization. Stream export accounted for the greatest loss of C, removing 247 and 113 mol hr^-1 in the early and late summer, respectively. Reactivity was related to hydrologic connectivity between the soils and stream, which was greatest early in the summer and following a large flood. While a warming climate may increase storage potential in thawed soils, the early-season flush of labile material and late-season runoff through mineral flowpaths may maintain high C export rates. Therefore, we highlight physical export as a dominant cause of aqueous C loss from silty catchments as the Arctic continues to thaw. Abstract Copyright (2013), American Geophysical Union. All Rights Reserved.

DOI: 10.1002/jgrg.20058

15120975 Andresen, Christian G. (University of Texas, El Paso, Environmental Science and Engineering Program, El Paso, TX) and Lougheed, Vanessa L. Disappearing Arctic tundra ponds; fine-scale analysis of surface hydrology in drained thaw lake basins over a 65 year period (1948-2013): Journal of Geophysical Research: Biogeosciences, 120(3), p. 466-479, illus. incl. 2 tables, sketch map, 61 ref., March 2015.

Long-term fine-scale dynamics of surface hydrology in Arctic tundra ponds (less than 1 ha) are largely unknown; however, these small water bodies may contribute substantially to carbon fluxes, energy balance, and biodiversity in the Arctic system. Change in pond area and abundance across the upper Barrow Peninsula, Alaska, was assessed by comparing historic aerial imagery (1948) and modern submeter resolution satellite imagery (2002, 2008, and 2010). This was complemented by photogrammetric analysis of low-altitude kite-borne imagery in combination with field observations (2010-2013) of pond water and thaw depth transects in seven ponds of the International Biological Program historic research site. Over 2800 ponds in 22 drained thaw lake basins (DTLB) with different geological ages were analyzed. We observed a net decrease of 30.3% in area and 17.1% in number of ponds over the 62 year period. The inclusion of field observations of pond areas in 1972 from a historic research site confirms the linear downward trend in area. Pond area and number were dependent on the age of DTLB; however, changes through time were independent of DTLB age, with potential long-term implications for the hypothesized geomorphologic landscape succession of the thaw lake cycle. These losses were coincident with increases in air temperature, active layer, and density and cover of aquatic emergent plants in ponds. Increased evaporation due to warmer and longer summers, permafrost degradation, and transpiration from encroaching aquatic emergent macrophytes are likely the factors contributing to the decline in surface area and number of ponds. Abstract Copyright (2015), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/2014JG002778

15120977 Lantz, T. C. (University of Victoria, School of Environmental Studies, Victoria, BC, Canada) and Turner, K. W. Changes in lake area in response to thermokarst processes and climate in Old Crow Flats, Yukon: Journal of Geophysical Research: Biogeosciences, 120(3), p. 513-524, illus. incl. 4 tables, geol. sketch map, 58 ref., March 2015.

Growing evidence indicates that lake-dominated ecosystems at high latitudes are undergoing significant hydrological changes. Research examining these changes is complicated because both thermokarst and climatic processes likely influence lake dynamics. To examine the relative impacts of these processes in permafrost landscapes, we investigated the dynamics of lake area and number in Old Crow Flats (OCF), Yukon using historical air photos and satellite imagery. Between 1951 and 2007, OCF experienced a decline of ~6000 ha in total lake area but gained 232 lakes. Close to half (49%) of the difference in lake area was driven by the rapid and persistent drainage of 38 large lakes. These catastrophic drainages were associated with new or enlarged outlet channels, resulted in the formation of numerous residual ponds, and were likely driven by thermokarst processes. Our analysis shows that catastrophic lake drainages have become more than 5 times more frequent in recent decades. These changes are likely related to the impacts of increased temperature and precipitation on thermokarst processes. Fifty-nine of the 170 intensively studied lakes showed either large bidirectional fluctuations or gradual cumulative declines. These changes affected a much smaller portion of OCF and were likely driven by interactions between increased precipitation and temperature and individual catchment characteristics. To anticipate landscape-scale changes in these systems, and assess their impact on hydrology, wildlife habitat, and carbon storage, field research is required to better characterize the mechanisms responsible for changes. Abstract Copyright (2015), . American Geophysical Union. All Rights Reserved.

DOI: 10.1002/2014JG002744

15114146 Matheus Carnevali, P. B. (Desert Research Institute, Division of Earth and Ecosystem Sciences, Reno, NV); Rohrssen, M.; Williams, M. R.; Michaud, A. B.; Adams, H.; Berisford, D.; Love, G. D.; Priscu, J. C.; Rassuchine, O.; Hand, K. P. and Murray, Alison E. Methane sources in arctic thermokarst lake sediments on the North Slope of Alaska: Geobiology, 13(2), p. 181-197, illus. incl. 1 table, sketch map, 89 ref., March 2015. NSF Grant DGE-0654336.

The permafrost on the North Slope of Alaska is densely populated by shallow lakes that result from thermokarst erosion. These lakes release methane (CH₄) derived from a combination of ancient thermogenic pools and contemporary biogenic production. Despite the potential importance of CH₄ as a greenhouse gas, the contribution of biogenic CH₄ production in arctic thermokarst lakes in Alaska is not currently well understood. To further advance our knowledge of CH₄ dynamics in these lakes, we focused our study on (i) the potential for microbial CH₄ production in lake sediments, (ii) the role of sediment geochemistry in controlling biogenic CH₄ production, and (iii) the temperature dependence of this process. Sediment cores were collected from one site in Siqlukaq Lake and two sites in Sukok Lake in late October to early November. Analyses of pore water geochemistry, sedimentary organic matter and lipid biomarkers, stable carbon isotopes, results from CH₄ production experiments, and copy number of a methanogenic pathway-specific gene (mcrA) indicated the existence of different sources of CH₄ in each of the lakes chosen for the study. Analysis of this integrated data set revealed that there is biological CH₄ production in Siqlukaq at moderate levels, while the very low levels of CH₄ detected in Sukok had a mixed origin, with little to no biological CH₄ production. Furthermore, methanogenic archaea exhibited temperature-dependent use of in situ substrates for methanogenesis, and the amount of CH₄ produced was directly related to the amount of labile organic matter in the sediments. This study constitutes an important first step in better understanding the actual contribution of biogenic CH₄ from thermokarst lakes on the coastal plain of Alaska to the current CH₄ budgets. Abstract Copyright (2010), John Wiley & Sons, Ltd.

DOI: 10.1111/gbi.12124

15118489 Christiansen, Jesper Riis (University of Copenhagen, Center for Permafrost, Copenhagen, Denmark); Romero, Alejandro Jose Barrera; Jorgensen, Niels O. G.; Glaring, Mikkel Andreas; Jorgensen, Christian Juncher; Berg, Louise Kristine and Elberling, Bo. Methane fluxes and the functional groups of methanotrophs and methanogens in a young Arctic landscape on Disko Island, West Greenland: Biogeochemistry (Dordrecht), 122(1), p. 15-33, illus. incl. 2 tables, sketch map, 64 ref., January 2015.

Arctic soils are known to be important methane (CH₄) consumers and sources. This study integrates in situ fluxes of CH₄ between upland and wetland soils with potential rates of CH₄ oxidation and production as well as abundance and diversity of the methanotrophs and methanogens measured with pyrosequencing of 16S DNA and rRNA fragments in soil and permafrost layers. Here, the spatial patterns of in situ CH₄ fluxes for a 2,000 years old Arctic landscape in West Greenland reveal similar CH₄ uptake rates (-4 ± 0.3 mmol m^-2 h^-1) as in other Arctic sites, but lower CH₄ emissions (14 ± 1.5 mmol m^-2 h^-1) at wetland sites compared to other Arctic wetlands. Potential CH₄ oxidation was similar for upland and wetland soils, but the wetter soils produced more CH₄ in active and permafrost layers. Accordingly, the abundance of methanogenic archaea was highest in wetland soils. The methanotrophic community also differed between upland and wetland soils, with predominant activity of Type II methanotrophs in the active layer for upland soils, but only Type I methanotrophs for the wetland. In the permafrost of upland and wetland soils, activity of the methanotrophs belonging to Type I and Type II as well as methanogens were detected. This study indicates that the magnitude of CH₄ oxidation and the direction of the flux, i.e. uptake or emission, are linked to different methanotrophic communities in upland and wetland soils. Also, the observed link between production/consumption rates and the microbial abundance and activity indicates that the age of an Arctic landscape is not important for the CH₄ consumption but can be very important for CH₄ production. Considering the prevalence of dry landscapes and contrasting ages of high Arctic soils, our results highlight that well-drained soils should not be overlooked as an important component of Arctic net CH₄ budget. Copyright 2014 Springer International Publishing Switzerland

DOI: 10.1007/s10533-014-0026-7

15115233 Marszalek, Henryk (Uniwersytet Wroclawski, Instytut Nauk Geologicznych, Zaklad Hydrogeologii Stosowanej, Wroclaw, Poland); Stasko, Stanislaw and Wasik, Miroslaw. Ocena odplywu podpowierzchniowego w rejonie Hornsundu (SW Spitsbergen) [Estimation of subsurface runoff in the Hornsund region (SW Spitsbergen)]: in Wspolczesne problemy hydrogeologii (Krogulec, Ewa, editor; et al.), Biuletyn Panstwowego Instytutu Geologicznego. Hydrogeologia, 456(2), p. 391-396 (English sum.), illus., 14 ref., 2013.

Based on hydrogeological investigations carried out in the Hornsund region (SW Spitsbergen) the mean water runoff amount was estimated to be 3.346 m3/s. The measurements were carried out in the coastal zone of the Greenland Sea with an area of 49.95 km2, limited by Werenskiold and Hans glaciers, during the summer seasons of 2005-2007. River and subsurface parts of total runoff amount to, respectively, 3.008 m3/s and 0.338 m3/s. Runoff is formed mainly by water from melting glaciers and permafrost, and secondarily from rainwater.

URL: http://9070.indexcopernicus.com/fulltxt.php?ICID=1113869

15117521 Rémillard, Audrey M. (Université du Québec à Rimouski, Institut des Sciences de la Mer de Rimouski, Rimouski, QC, Canada); Hétu, Bernard; Bernatchez, Pascal; Buylaert, Jan-Pieter; Murray, Andrew S.; St-Onge, Guillaume and Geach, Martin. Chronology and palaeoenvironmental implications of the ice-wedge pseudomorphs and composite-wedge casts on the Magdalen Islands (Eastern Canada): Boreas, 44(4), p. 658-675, illus. incl. 5 tables, sketch map, 100 ref., October 2015.

The Magdalen Islands are a valuable terrestrial record, evidencing the complex glacial and periglacial history of the Gulf of St. Lawrence. Thirteen structures interpreted as ice-wedge pseudomorphs or composite-wedge casts were observed at four sites on the southern Magdalen Islands and testify to the former presence of permafrost under periglacial conditions. These features truncate Carboniferous sandstone or Last Glacial Maximum (LGM) glacial and glaciomarine diamicts, both overlain by subtidal or coastal units. Six optically stimulated luminescence (OSL) and four radiocarbon ages were obtained from both host and infilled sedimentary units. These ages provide the first absolute chronological data on these structures, shedding new light on the relationships between glacial and periglacial phases. Our chronostratigraphic data suggest that, after the deglaciation and the emersion of the archipelago, thermal contraction cracks grew during the cold period of the Younger Dryas (11-10 ka; 12.9-11.5 cal. ka BP). The Younger Dryas, which is well documented in the Maritime Provinces of Canada, occurred after a pedogenesis phase associated with the Allerod warm period evidenced by the well-developed palaeopodzol ubiquitous on the Magdalen Islands. Abstract Copyright (2010), John Wiley & Sons, Ltd.

DOI: 10.1111/bor.12125

15118388 Song Yongchen (Dalian University of Technology, School of Energy and Power Engineering, Dalian, China); Zhu Yiming; Liu Weiguo; Zhao Jiafei; Li Yanghui; Chen Yunfei; Shen Zhitao; Lu Yan and Ji Chongming. Experimental research on the mechanical properties of methane hydrate-bearing sediments during hydrate dissociation: Marine and Petroleum Geology, 51, p. 70-78, illus. incl. 5 tables, 33 ref., March 2014.

This paper describes studies of the effect of hydrate dissociation on the safety and stability of methane hydrate-bearing sediments. Methane hydrates within the sediments were dissociating under the conditions of a confining pressure of 0.5 MPa, 1 MPa, 2 MPa and a temperature of -5°C. After 6 h, 24 h, or 48 h, a series of triaxial compression tests on methane hydrate-bearing sediments were performed. The tests of ice-clay and sediments without hydrate dissociation were performed for comparison. Focusing on the mechanical properties of the sediments, the experimental results indicated that the shear strength of the ice-clay mixtures was lower than that of the methane hydrate-bearing sediments. The strength of the sediments was reduced by hydrate dissociation, and the strength tended to decrease further at the lower confining pressures. The secant modulus E_S of the sediments dropped by 42.6% in the case of the dissociation time of the hydrate of 48 h at the confining pressure of 1 MPa; however, the decline of the initial yield modulus E₀ was only 9.34%. The slower hydrate dissociation rate contributed to reducing the failure strength at a declining pace. Based on the Mohr-Coulomb strength theory, it was concluded that the decrease in strength was mainly affected by the cohesive reduction. Moreover, the mathematical expression of the M-C criterion related to the hydrate dissociation time was proposed. This research could be valuable for the safety and stability of hydrate deposits in a permafrost region. Abstract Copyright (2014) Elsevier, B.V.

DOI: 10.1016/j.marpetgeo.2013.11.017

15121492 Majorowicz, Jacek A. (Northern Geothermal Consulting, Edmonton, AB, Canada) and Minea, Vasile. Shallow and deep geothermal energy potential in low heat flow/cold climate environment; northern Quebec, Canada, case study: Environmental Earth Sciences, 74(6), p. 5233-5244, illus. incl. sketch map, 28 ref., September 2015.

Northern Quebec, a large and cold climate territory located north of the 49th parallel, has low average heat flow density (40 ± 9 mW/m²) typical of the Canadian Shield. The lack of the thermal blanket otherwise provided by sediments in the platform of southern Quebec results in deep drilling requirements for potential mining heat (80 °C at some 5 km). Drilling doublet or triplet well systems at such depths into low-enthalpy granitic rocks would be expensive; however, in some cases of heat flow higher by one standard deviation of the mean and fracked permeability allowing flow rates >30 kg/s may make this heat useable in the future. Other options in providing heat are more likely to be applied earlier. These would include shallow geothermal energy use with heat pumps in granites by placement of artificial heat exchanges by directional loop drilling. These systems may have promise in Northern Quebec due to its very cold climate and extremely high energy cost based on diesel oil heating for remote communities and mining areas. Findings show that recent industrial age climatic warming increased the mean underground temperatures in the upper circa couple hundred meters. This has resulted in temperature gains and energy ground storage. Copyright 2015 Springer-Verlag Berlin Heidelberg

DOI: 10.1007/s12665-015-4533-1

15112541 Gobbi, Mauro (Museo delle Scienze di Trento, Trento, Italy); Ballarin, Francesco; Compostella, Chiara; Lencioni, Valeria; Seppi, Roberto; Tampucci, Duccio and Caccianiga, Marco. Physical and biological features of an active rock glacier in the Italian Alps: Holocene, 24(11), p. 1624-1631, illus. incl. 1 table, sketch map, 36 ref., November 1, 2014.

We report on the key physical features of an active rock glacier that influence the distribution of plants and arthropods. We also perform a comparison with neighboring scree slope and alpine grassland to test whether the environmental features of the rock glacier drive the presence of specific species assemblages. Compared with scree slope and grassland, the studied rock glacier provides particular physical features that determine the presence of unique species. Plant distribution is mainly driven by grain size. Arthropod distribution is linked to grain size, with cold-adapted species found on areas with coarse-grained deep debris, which also shows a distinctive temperature regime with very low values throughout the year. On the basis of these findings, we advance the hypothesis that rock glaciers provide specific ecological conditions creating potential refugia for cold-demanding species during warm climatic periods.

DOI: 10.1177/0959683614544050

15116257 Schreiner, Kathryn M. (Texas A&M University, Department of Oceanography, College Station, TX); Bianchi, Thomas S.; Eglinton, Timothy I.; Allison, Mead A. and Hanna, Andrea J. M. Sources of terrigenous inputs to surface sediments of the Colville River delta and Simpson's Lagoon, Beaufort Sea, Alaska: Journal of Geophysical Research: Biogeosciences, 118(2), p. 808-824, illus. incl. 6 tables, sketch map, 81 ref., June 2013.

The provenance of sediments and particulate organic carbon (POC) in the Colville River delta and adjacent Simpson's Lagoon, in the Alaskan Beaufort Sea, was investigated using a variety of bulk and molecular techniques, including stable and radiocarbon isotopes, neodymium isotopes, algal pigments, and lignin-phenols. Additionally, stable carbon isotopes and lignin-phenols were analyzed on four different density fractions from sediments. The Colville River, the largest river in North America with a watershed exclusively located in the high-Arctic tundra, was an important source of terrestrial POC to the western edge of the Lagoon, shown by extremely old radiocarbon ages (fraction modern of 0.165 ± 0.001 close to the river mouth up to 0.418 ± 0.002 farther away). Stations without northern protective barrier islands had large amounts of marine POC input, and evidence of benthic microalgae was found in one area of the Lagoon (chlorophyll-a concentration 35.0 mg gOC^-1 in the high-algal biomass area compared to 1 to 7 mg gOC^-1 outside of it). Stations in the middle and eastern end of the Lagoon showed significant sediment input from coastal erosion (input of peat-indicating non-lignin-phenols 0.079 mg (100 mgOC)^-1 in the eastern lagoon compared to 0.022 mg (100 mgOC)^-1 near the Colville delta), and on the eastern end of the Lagoon there was evidence of input of Mackenzie River POC, shown with neodymium isotopes and also COP. POC inputs derived from rivers, coastal erosion, and marine productivity were quantified using a ternary mixing model and showed that fluvial supply and coastal erosion were the dominant carbon sources to the Lagoon. This constitutes the first study of POC delivery by the Colville River into a nearshore region and illustrates that continued warming of the high Arctic tundra will likely lead to increased riverine POC delivery to this region of the world. Abstract Copyright (2013), American Geophysical Union. All Rights Reserved.

DOI: 10.1002/jgrg.20065

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15120020 Ballantyne, C. K. (University of Saint Andrews, St. Andrews, United Kingdom). Permafrost and periglacial features; patterned ground: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 452-463, 2013.

Patterned ground is terrain exhibiting surface patterning, primarily in the form of circles, polygons, irregular networks, or stripes. Sorted patterns are defined by alternating soil and clasts, and nonsorted patterns by microrelief or vegetation. Most patterns form through recurrent ground freezing and thawing and are initiated by differential (laterally nonuniform) frost heave. Small sorted forms are produced by shallow differential frost heave or needle-ice heave. Large sorted patterns are probably initiated by differential frost heave, but may develop through buoyancy-driven soil circulation during thaw. Frost polygons develop through recurrent thermal contraction cracking of permafrost and freezing of meltwater in cracks. Earth hummocks and vegetation-defined nonsorted circles are probably initiated by differential frost heave, though buoyancy-driven soil circulation and other mechanisms may contribute to their subsequent development.

DOI: 10.1016/B978-0-444-53643-3.00098-4

15120015 Burn, C. R. (Carleton University, Ottawa, ON, Canada). Permafrost and periglacial features; permafrost: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 464-471, 2013.

Permafrost is the ground that remains at or below 0 °C for 2 years or more, and is therefore a geologic manifestation of climate. At present, permafrost underlies about 25% of the land surface of the Earth; it extends beneath great portions of Alaska and Canada, Siberia, and the Tibetan Plateau and is found at high elevation in mountains throughout the globe. The spatial extent of permafrost has varied with climate and global ice cover during the Quaternary. Permafrost terrain consists of a surface active layer, which freezes and thaws each year, underlain by perennially frozen ground. Variations in active-layer thickness over time commonly alter the nature and form of near-surface ground ice and the associated cryostratigraphy. Since ground temperatures are a product of both climate and surface conditions, changes in active layer or permafrost conditions may be caused by alterations to vegetation or snow cover as well as climate. At present, considerable quantities of carbon are stored in permafrost, both in peatlands and mineral soils, and release of such carbon following permafrost thawing may accentuate climate change. Data collected throughout the circumpolar North indicate that the temperature in near-surface permafrost has increased in response to climate warming.

DOI: 10.1016/B978-0-444-53643-3.00099-6

15120022 Burn, C. R. (Carleton University, Ottawa, ON, Canada). Permafrost and periglacial features; thermokarst topography: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 574-581, 2013.

Permafrost terrain consists of a seasonally thawed active layer underlain by perennially frozen ground. Permafrost immediately below the base of the active layer is commonly ice rich. Thermokarst terrain is the pitted relief formed by the melting of ground ice, and develops throughout the permafrost regions after surface disturbance or climate warming. In the boreal forest, the most widespread surface disturbances are caused by forest fires, and commonly landslides occur in areas that have been burned. Thermokarst depressions may contain ponds that grow into lakes as the surrounding permafrost thaws and the depression enlarges. Where ice-rich ground is exposed by river, lake, or coastal erosion, rapid ablation of the permafrost occurs. Retrogressive thaw slumps, consisting of a steep headwall of melting ice-rich ground and a foot slope of lower gradient, develop following such erosion. Where near-surface ground ice thaws on hillslopes, excess pore-water pressures may lead to a reduction in effective stress and failure of the slope. The sedimentary records of most thermokarst features are disorganized beds of organic debris mixed with mineral deposits. Thermokarst lake development in northwest North America has been associated with periods of relatively warm climate, but the initiation of individual lakes is the result of site-specific disturbances.

DOI: 10.1016/B978-0-444-53643-3.00091-1

15120028 Kaab, A. (University of Oslo, Oslo, Norway). Permafrost and periglacial features; rock glaciers and protalus forms: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 535-541, 2013.

Perennially frozen debris in cold mountains may, under the force of gravity, form so-called rock glaciers, which often show a shape similar to that of lava streams. On account of their ice-rich cores, these features creep with surface speeds of up to several meters per year, transporting talus or glacial debris to terrain at lower altitudes. Rock glaciers are intimately related to permafrost conditions and thus are coupled to climate and climatic changes. Their most important characteristics are their thermal conditions, composition and internal structure, creep and advance mechanisms, shape and surface morphology, activity stages and age, and reaction to environmental changes. Rock glaciers can show complex interactions and combinations with other forms and processes in cold mountains.

DOI: 10.1016/B978-0-444-53643-3.00104-7

15120031 Schirrmeister, L. (Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany); Froese, D.; Tumskoy, V.; Grosse, G. and Wetterich, S. Permafrost and periglacial features; yedoma; late Pleistocene ice-rich syngenetic permafrost of Beringia: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 542-552, 2013.

Syngenetically frozen deposits that are fine-grained and ice-rich are widely distributed in the lowlands of northeastern Siberia, Alaska, and northwestern Canada. These late Pleistocene sediments are specific to this region summarized as Beringia, and have been termed 'Ice Complex' or 'Yedoma' in Siberia, and 'muck' in North America. Silt is their dominant material, but they also include abundant organic matter preserved in permafrost since the time of deposition. Vegetation and faunal reconstructions indicate that the sediments aggraded largely under a cryoxeric environment characterized by graminoid- and forb-rich vegetation that supported a grazing megafauna population during the Pleistocene.

DOI: 10.1016/B978-0-444-53643-3.00106-0

15120016 Shiklomanov, N. I. (George Washington University, Washington, DC) and Nelson, F. E. Permafrost and periglacial features; active layer processes: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 421-429, 2013.

The active layer is defined as the layer of ground that is subject to annual thawing and freezing in areas underlain by permafrost. The active layer is the only part of the permafrost system that experiences substantial changes in its physical properties during each annual cycle. Most geomorphic, biological, and hydrological activities in permafrost-affected soils are confined to the layer of seasonal thaw. Changes in its thickness induced by human action or climatic change can have profound consequences for ecological systems and human infrastructure.

DOI: 10.1016/B978-0-444-53643-3.00095-9

15120029 van Huissteden, J. (VU University Amsterdam, Amsterdam, Netherlands); Vandenberghe, J.; Gibbard, P. L. and Lewin, J. Permafrost and periglacial features; periglacial fluvial sediments and forms: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 490-499, 2013.

This article describes fluvial deposits and landforms generated under cold-climate or periglacial conditions. It discusses the terminology of these deposits and presents an overview of their associated fluvial morphology, hydrology, sediment supply and transport, as well as the role of ice cover and permafrost, and the carbon cycle. Examples of Pleistocene periglacial fluvial deposits are summarized from southern Britain and continental Europe. This article concludes with an outlook on the effects of future climate change on fluvial systems in contemporary periglacial regions.

DOI: 10.1016/B978-0-444-53643-3.00108-4

15120030 Waller, R. I. (Keele University, Newcastle-under-Lyme, United Kingdom). Permafrost and periglacial features; permafrost and glacier interactions: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 507-513, 2013.

There is growing recognition that glaciers can actively couple with permafrost and that these interactions influenced both the dynamics of Pleistocene ice sheets and the associated geomorphological and geological records, particularly in high-latitude regions. This article considers the formation and key characteristics of permafrost in glacial environments and the likely extent of glacier-permafrost interactions. Recent reappraisals of the role of basal processes at subfreezing temperatures are highlighted, along with their potential impact on the dynamic and geomorphic behavior of glaciers resting on permafrost. Finally, the landforms and landform assemblages associated with glacier-permafrost interactions are explored along with the geological evidence in situations where the permafrost has persisted since deglaciation and those where it has subsequently thawed.

DOI: 10.1016/B978-0-444-53643-3.00107-2

15120026 Wilson, P. (University of Ulster, Coleraine, United Kingdom). Permafrost and periglacial features; block/rock streams: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 514-522, 2013.

Block streams comprise linear accumulations of coarse openwork rock debris that have moved or are moving downslope in areas of past or present periglacial conditions, respectively. Differences exist in block-stream plan forms, dimensions, morphology, and structure and composition, and a variety of processes act in combination and/or succession during their development. Relict block streams are frequently regarded as a result of macrogelivation, mass wasting, and frost heaving/sorting, with immobilization due to removal of fine-grained matrix materials. Where active block streams are associated with permafrost, they may be the cause of permafrost aggradation rather than a consequence of it. Many relict block streams are in areas that were adjacent to the ice margin during the Last Glacial Maximum.

DOI: 10.1016/B978-0-444-53643-3.00102-3

15120023 Murton, J. (University of Sussex, Permafrost Laboratory, Brighton, United Kingdom). Permafrost and periglacial features; ice wedges and ice-wedge casts: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 436-451, 2013.

Ice wedges are steep to vertically laminated bodies of ice that form by repeated infilling of thermal contraction cracks in permafrost. Soil wedges form where the cracks fill with soil, and composite wedges form where they fill with mixtures of soil and ice. The size and shape of the wedges, and the relative age of the wedge infill and host material, depend on the interactions between thermal contraction cracking and ground-surface stability. The thawing of ice veins and wedges sometimes results in secondary infilling of the space left by melting ice, the infilling mechanisms being determined by thaw consolidation, tunnel collapse and groundwater movement. The resulting ice-wedge pseudomorphs or casts are common in terrestrial cold-climate sediment sequences and indicate the former occurrence of permafrost. The paleoenvironmental significance of small, relict veins and wedges is often difficult to pinpoint because thermal contraction cracking occurs frequently in areas of continuous permafrost, rarely or locally in discontinuous permafrost and occasionally in seasonally frozen ground.

DOI: 10.1016/B978-0-444-53643-3.00097-2

15120027 Murton, J. (University of Sussex, Permafrost Laboratory, Brighton, United Kingdom). Permafrost and periglacial features; rock weathering: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 500-506, 2013.

Frost weathering processes involve (1) volumetric expansion as liquid water changes to ice within rock or mineral particles, and (2) migration of liquid water toward freezing sites where growing ice lenses fracture rock (ice segregation). Mechanical weathering processes unrelated to ice formation include hydration shattering in clay-rich rocks and thermally induced stress near rock surfaces. Chemical and biological weathering processes are also active in many periglacial and permafrost regions, with rates of chemical erosion in mid-latitude alpine periglacial environments (9-100 t/km2/year) broadly similar to the global average for all rock types (45 t/km2/year). Rockwall retreat rates in alpine regions have an overall mean of 1.1 m/ka, distinctly greater than that of 0.3 m/ka from arctic regions. The products of cold-climate weathering include silt- to boulder-sized debris, weathering rinds and chemical rock coatings, a variety of rock-surface features, tors and rockwalls, and weathering profiles characterized by fractures parallel to the cooling surface.

DOI: 10.1016/B978-0-444-53643-3.00105-9

15120019 Ross, N. (Newcastle University, Newcastle upon Tyne, United Kingdom). Permafrost and periglacial features; frost mounds; active and relict forms: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 472-480, 2013.

Frost mounds are ice-cored mounds or hills found in present-day environments characterized by permafrost or seasonally frozen ground. The formation of these landforms during Quaternary cold periods has been inferred from the presence of circular or ovate depressions surrounded by raised rampart-like rims ('ramparted depressions') in now-temperate mid-latitude environments. Such landforms were at one time almost universally interpreted as the remains of pingos. Many smaller ground-ice phenomena (i.e., lithalsas, palsas, and seasonal ground-ice mounds) also exist, however, and greater understanding of these smaller ground-ice mounds has driven the reinterpretation of many ramparted depressions as lithalsa remnants. This article reviews the nature, origin, and geomorphic evolution (growth and decay) of all types of frost mound, evaluating the long-term preservation potential for each type. In addition, it highlights nonperiglacial processes (e.g., the melt of buried glacier ice) which can also lead to the development of ramparted depressions, hindering simple interpretation of such landforms.

DOI: 10.1016/B978-0-444-53643-3.00100-X

15120024 Vandenberghe, J. (VU University Amsterdam, Amsterdam, Netherlands). Permafrost and periglacial features; cryoturbation structures: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 430-435, 2013.

Six types of cryoturbation structures (sedimentary deformations of cryogenic origin) can be distinguished and attributed to different mechanisms of formation and specific environmental conditions. Cryoturbations may result from (1) gravitational loading in thawing soil ('periglacial loading'), (2) hydrostatic pressure between frozen parts of the subsoil ('cryohydrostatic pressure'), or (3) ice-induced pressures due to differential frost penetration ('cryostatic heave'). The first, and most common, process requires a reversed density gradient and conditions of liquefaction that are possible only during thaw of underlying frozen subsoil. The other two processes occur during freezing. Only large-amplitude deformations due to periglacial loading indicate the existence of perennially frozen ground and, therefore, provide important paleoclimatic proxy indicators. The other cryoturbation types do not require permafrost conditions; they simply require deep seasonal frost or repeated freeze-thaw cycles. Cryoturbations may enhance the storage of organic carbon in the soil and influence the global carbon cycle.

DOI: 10.1016/B978-0-444-53643-3.00096-0

15120017 Ballantyne, C. K. (University of Saint Andrews, St. Andrews, United Kingdom). Permafrost and periglacial features; paraglacial geomorphology: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 553-565, 2013.

Paraglacial geomorphology is the study of how nonglacial earth-surface processes modify glaciated landscapes. Glacier retreat exposes glacigenic and glacially conditioned sediment sources (rockwalls, drift-mantled slopes, valley-floor glacigenic deposits, and coastal glacigenic deposits) in an unstable or metastable state. During sediment reworking, source-to-sink transport is interrupted by storage in a range of paraglacial landforms such as talus, debris cones, alluvial fans, valley fills, deltas, and coastal barrier deposits. Because glacigenic sediment sources are nonrenewable, paraglacial sediment flux can be approximated by an exhaustion model, and sediment stores experience a transition from net accumulation to net degradation. Six paraglacial land systems are identified (rock-slope adjustment, drift-mantled slopes, glacier forelands, and alluvial, lacustrine, and coastal settings). Paraglacial effects dominate the postglacial geomorphic evolution of most glaciated environments.

DOI: 10.1016/B978-0-444-53643-3.00089-3

15120018 Harris, C. (Cardiff University, Cardiff, United Kingdom). Permafrost and periglacial features; slope deposits and forms: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 481-489, 2013.

On steep bedrock slopes, ground freezing and thawing leads to weathering and the release of rock falls, and where gradients are less, such frost action helps generate a weathering mantle. Debris-mantled slopes are susceptible to solifluction, the combined effect of frost creep and gelifluction. Frost creep results from frost heaving of the near-surface soil by segregation or needle ice and subsequent near-vertical settlement during thaw. Gelifluction occurs during thawing of ice-rich soils when high moisture contents result in a very soft, easily deformed soil mass. When the rate of thaw is rapid, pore pressures may be high enough to release shallow landslides. In mountain regions, rapid saturation of the active layer by intense rainfall can lead to debris flows. Thus, many periglacial slopes become mantled with deposits dominated by solifluction sediments but containing evidence of more rapid mass movement events. In areas with clay bedrocks, shallow translational landslides were often the dominant mechanism of periglacial mass movement, as evidenced by extensive shallow shear surfaces underlying partially remolded clay-rich slope deposits.

DOI: 10.1016/B978-0-444-53643-3.00101-1

15120021 Luckman, B. H. (Western University, London, ON, Canada). Permafrost and periglacial features; talus slopes: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 566-573, 2013.

This article discusses the plan and profile morphology, characteristics, composition, and origin of talus (scree) slopes and describes the main formative processes (including rock fall, talus creep, and grain flows). It also briefly illustrates the modification of talus by snow avalanches and debris flows. Finally, it discusses in brief the rate of formation of talus, their possible paraglacial origin in some cases, and paleoenvironmental interpretation of talus deposits.

DOI: 10.1016/B978-0-444-53643-3.00090-X

15120025 Rea, B. R. (University of Aberdeen, Aberdeen, United Kingdom). Permafrost and periglacial features; blockfields (Felsenmeer): in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 523-534, 2013.

Blockfields are a common feature on many summit ridges and plateaux in contemporary and formerly glaciated landscapes. They are often enigmatic, possessing characteristics and a geochemistry that is in nonequilibrium with the present climate, suggesting some antiquity. However, they are often found in proximity to intense glacial erosion and may even have erratics on the surface. Contemporary approaches to investigating and interpreting mid- to high-latitude blockfields provide insights into long-term landscape evolution, selective linear erosion, the geometries and basal thermal regimes of glaciers and ice sheets, and past and present weathering environments.

DOI: 10.1016/B978-0-444-53643-3.00103-5

15120143 Bigelow, N. H. (University of Alaska Fairbanks, Fairbanks, AK); Zazula, G. D. and Atkinson, D. E. Plant macrofossil records; Arctic North America: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 746-759, 2013.

Plant macrofossil records in northern North America from the late Pliocene through the Holocene provide detailed snapshots of vegetation during the past 2.5 million years. late Pliocene records document northern extension of trees and shrubs, indicating climate was significantly warmer than today. During the early to middle Pleistocene, climate had cooled somewhat, but the vegetation reconstructions still indicate that climate during interglaciations was somewhat warmer than today. The last ice-free period in the north (ca. 125 000 years ago (125 kya)) was also warmer than today, as indicated by treeline extension. By approximately 60-30 kya, most sites document forest retraction, indicating slightly cooler than modern climate. During the Last Glacial Maximum (ca. 21 kya), plant macrofossil records indicate a mosaic of mesic to dry tundra (with some steppe affinities) across the ice-free refugium of Beringia, indicating significantly cooler and drier conditions. Holocene-aged macrofossil sites document treeline advance in the early Holocene and subsequent retreat, whereas some sites also reflect changing hydrology with permafrost expansion and/or peat development. Macrofossil records add important details to existing pollen results because they do not travel great distances and are often identifiable to the species level.

DOI: 10.1016/B978-0-444-53643-3.00214-4

15120053 Elias, Scott A. (Royal Holloway University of London, Egham, United Kingdom) and Brigham-Grette, J. Glaciations; late Pleistocene glacial events in Beringia: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 191-201, 2013.

The region of the western Arctic stretching from the Lena River in northeast Russia to the Mackenzie River in Canada is geographically known as Beringia. The lowlands of Beringia remained ice-free during Pleistocene glaciations, while nearly all other high-latitude regions of the Northern Hemisphere were covered by ice sheets. The lowering of sea level during glacial stadials exposed large regions of the Bering and Chukchi sea shelves, repeatedly forming the Bering Land Bridge. The Bering Land Bridge cut off circulation between the waters of the North Pacific and Arctic oceans, greatly increasing the continentality of adjacent land masses and diminishing the inland flow of relatively warm, moist air masses from the North Pacific (Harris SA (2005) Thermal history of the Arctic Ocean environs adjacent to North America during the last 3.5 Ma and a possible mechanism for the cause of cold events (major glaciations and permafrost events). Progress in Physical Geography 29: 1-19).

DOI: 10.1016/B978-0-444-53643-3.00116-3

15120188 Elias, Scott A. (Royal Holloway University of London, Egham, United Kingdom) and Kuzmina, S. Beetle records; late Tertiary and early Quaternary records: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 173-183, 2013.

During the past 30 years, Quaternary insect paleontologists working in the Arctic have studied rare deposits of fossil insects that date back millions of years. Some of these fossils may be as old as the late Miocene. The fossils have been preserved mostly in permafrost environments, and their state of preservation is often exceptional. The vast majority of identifiable beetle specimens match modern, extant species. This morphological constancy through time appears to reflect constancy of physiological adaptations, as well. The latter aspect is demonstrated indirectly through the ecological compatibility of species found in the ancient fossil assemblages. While most of the species themselves appear to have remained constant, the biological communities in which they lived have shifted dramatically through time. Based on both insect and plant fossil data, Late Tertiary environments of the Arctic were substantially warmer than they are today, supporting the growth of coniferous forests, up to the shores of the ancient Arctic Ocean. By about 2 Ma or shortly thereafter, the precursors of Arctic tundra communities came into existence in parts of Beringia. Arctic insect faunal diversity declined markedly with the onset of Quaternary glaciations.

DOI: 10.1016/B978-0-444-53643-3.00264-8

15119937 Miller, G. H. (University of Colorado Boulder, Boulder, CO); Brigham-Grette, J.; Alley, R. B.; Anderson, L.; Bauch, H. A.; Douglas, M. S. V.; Edwards, M. E.; Elias, Scott A.; Finney, B. P.; Fitzpatrick, J. J.; Funder, S. V.; Geirsdottir, A.; Herbert, T. D.; Hinzman, L. D.; Kaufman, D. S.; MacDonald, G. M.; Polyak, L.; Robock, A.; Serreze, M. C.; Smol, J. P.; Spielhagen, R.; White, J. W. C.; Wolfe, A. P. and Wolff, E. W. Paleoclimate; paleoclimate history of the Arctic: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 113-125, 2013.

Although the Arctic occupies less than 5% of the Earth's surface, it includes some of the strongest positive feedbacks in the climate system. Reconstructing the climate history of the Quaternary requires a suite of climate proxies that can be placed in a secure time frame. Most Arctic proxies reflect past summer temperatures, although a subset is sensitive to winter temperatures and/or precipitation. During the Quaternary, the Arctic has experienced a greater change in temperature, vegetation, and ocean surface characteristics than has any other Northern Hemisphere latitudinal band. Arctic temperature amplification is a consequence of several strong positive feedbacks. They include the fast feedbacks of snow and ice albedo, sea-ice insulation, vegetation, and permafrost, as well as a suite of slower responding feedbacks operating on glacial-interglacial timescales tied to the growth and decay of aerially extensive, thick continental ice sheets. Large changes in Arctic temperatures impact regions outside the Arctic through their proximal influence on the planetary energy balance and circulation of the Northern Hemisphere atmosphere and ocean, and with potential global impacts through changes in sea level, the release of greenhouse gases, and impacts on the ocean's meridional overturning circulation. Quantitative paleoclimate reconstructions for specific cold and warm times during the Quaternary suggest that Arctic temperature changes have been 3 to 4 times the corresponding hemispheric or globally averaged changes. This article provides a brief overview of climate changes leading up to the last ice age, then overviews the changes in Arctic climate during the Quaternary.

DOI: 10.1016/B978-0-444-53643-3.00030-3

15120169 Schreve, D. C. (Royal Holloway University of London, Egham, United Kingdom). Vertebrate overview: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 590-597, 2013.

Quaternary vertebrate fossils (mammals, birds, amphibians, reptiles, and fish) have a long-established history of research and represent some of the most spectacular and unusual life-forms ever known on Earth. They are generally well preserved in a diversity of depositional environments ranging from the Arctic permafrost to dry Australian caves. Their remains are easily extracted from sediments and interglacial faunal assemblages are frequently highly diverse, with more than 50 species present. Vertebrates can contribute to reconstructions of past environments and paleobiogeography since the profound climatic changes witnessed during the Quaternary caused large-scale expansion and contraction of their ranges. However, the warm-blooded mammals are more tolerant of a wider range of environments than birds or cold-blooded vertebrates. For this reason, reptiles, amphibians, and fish are more suitable indicators of past climates and environments, since they are most sensitive to changes in atmospheric and water temperatures and vegetation. In contrast, mammalian responses to past environmental change have included changing their body size and shape (often to a dramatic degree) as well as their distribution. In-depth analysis of large vertebrate assemblages in particular has yielded an enormous amount of detail on the paleobiology of these animals, including aspects of diet, locomotion, and behavior. One of the most useful applications of vertebrate studies has been to the field of biostratigraphy through the analysis of features such as assemblage composition, size change, origination and extinction, and the significant patterns of morphological evolution that are observable in many lineages. This has led to the construction of new chronological frameworks for the ordering and correlation of climatic events for time periods beyond the range of radiocarbon and in areas where other materials suitable for absolute dating may be absent. In addition, the study of Quaternary vertebrates can shed light on patterns of early human behavior, particularly issues concerning resource utilization, subsistence, art, and domestication.

DOI: 10.1016/B978-0-444-53643-3.00243-0

15120182 Harington, C. R. (Canadian Museum of Nature, Ottawa, ON, Canada). Vertebrate records; late Pleistocene mummified mammals: in Encyclopedia of Quaternary science (Elias, Scott A., editor; et al.), 2nd edition, Elsevier, Amsterdam, Netherlands, p. 713-717, 2013.

Mummified remains are the most spectacular of Ice Age mammal fossils. They give a good idea of how some of the extinct large species (megafauna) would have appeared. Further, they may yield: important DNA evidence; knowledge of soft tissue structure, paleopathology, and paleodiet; information on parasites, predators, scavengers; and paleoclimate. At least 16 species of Ice Age mammals have been mummified. Most carcasses are preserved by a type of freeze-drying in frozen ground of Russia (Siberia), United States (Alaska), and Canada (Yukon), and date between about 50-25 and 15-10 ka. However, some are mummified in dry, stable cave environments; and others have been 'pickled' in a saline solution associated with a petrochemical seep.

DOI: 10.1016/B978-0-444-53643-3.00246-6

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15117560 Angelopoulos, Michael (Golder Associates, Montreal, QC, Canada); Dagenais, Anne-Marie; Gince, Patrick; Kissiova, Mayana; Anderson, Steve and Stephani, Eva. Surface water infiltration impacts on the performance of thermal capping systems for waste rock in continuous permafrost: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 6 tables, 13 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117558 Baba, Hafeez (SNC-Lavalin, Toronto, ON, Canada); Oswell, Jim; Matusiewicz, Kristopher and Militano, Giovanni. Geotechnical deep foundation design challenges in discontinuous permafrost of northern Manitoba: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 7 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119169 Bellehumeur-Génier, Olivier (University of Ottawa, Department of Geography, Ottawa, ON, Canada) and Lewkowicz, Antoni G. Permafrost patch size in the sporadic discontinuous and isolated patches permafrost zones, southern Yukon and northern B.C.: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 3 tables, 12 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119221 Bevington, Alexandre (Ministry of Forests, Lands and Natural Resource Operations, Prince George, BC, Canada) and Lewkowicz, Antoni G. Assessment of a land cover driven TTOP model for mountain and lowland permafrost using field data, southern Yukon and northern British Columbia, Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 26 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119210 Bouchard, Frédéric (Université de Montréal, Département de Géographie, Montreal, QC, Canada); Fortier, Daniel; Paquette, Michel; Bégin, Paschale N.; Vincent, Warwick F. and Laurion, Isabelle. Lake bottom imagery; a simple, fast and inexpensive method for surveying shallow freshwater ecosystems of permafrost regions: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 23 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117609 Braverman, Michael (INSPEC-SOL, Waterloo, ON, Canada) and Quinton, William L. The effects of permafrost degradation on the hydrological regime of subarctic peatlands: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 22 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119184 Calmels, Fabrice (Yukon College, Yukon Reserch Centre, Whitehorse, YT, Canada); Laurent, Cyrielle; Brown, Ryan; Pivot, Frédérique and Ireland, Margaret. How permafrost thaw may impact food security of Jean Marie River First Nation, NWT: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, sketch maps, 15 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117638 Calmels, Fabrice (Yukon College, Northern Climate ExChange, Whitehorse, YT, Canada); Roy, Louis-Philippe; Laurent, Cyrielle; Pelletier, Maude; Kinnear, Lacia; Benkert, Bronwyn; Horton, Brian and Pumple, Joel. A practical guide to permafrost vulnerability for Yukon's north Alaska Highway: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, 8 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119182 Carbonneau, Andrée-Sylvie (University Laval, Department of Geography, Laval, QC, Canada); L'Hérault, Emmanuel; Aubé-Michaud, Sarah; Allard, Michel and Frappier, Diane. Construction potential maps in support to climate change adaptation and management strategies for communities built on permafrost; case studies from northern Quebec: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch maps, 19 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117568 Cassidy, A. E. (University of British Columbia, Department of Geography, Vancouver, BC, Canada); Desforges, M. and Henry, G. H. R. Ecosystem impacts of High Arctic permafrost disturbances: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 3 tables, 24 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117564 Cheng Guodong (Chinese Academy of Sciences, Cold and Arid Regions Enviornemntal and Engineering Research Institute, Lanzhou, China); Cui Zhijiu; Wang, Baolai and Jin Huijun. John Ross Mackay; devoted tutor and best friend of Chinese permafrost research: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 14 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115173 Christiansen, Hanne H. (University Centre in Svalbard, Geology Department, Svalbard and Jan Mayen Islands); Boike, Julia; van Huissteden, Ko; Hansen, Birger U.; Johansson, Margareta; Iwahana, Go and Biskaborn, Boris K. Arctic permafrost thermal variability across an environmental gradient from continuous to sporadic permafrost in the Northern Hemisphere; a PAGE21 compilation: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 9 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117559 Dalai, Dashjamts (Mongolian University of Science and Technology, Ulaanbaatar, Mongolia); Enebish, Ninjgarav; Anand, Batsaikhan and Anand, Ariunjargal. Research on foundation design on permafrost in Mongolia: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 3 tables, 7 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117607 Dallimore, S. R. (Geological Survey of Canada, Pacific Division, Sidney, BC, Canada); Paull, C. K.; Taylor, A. E.; Riedel, M.; MacAulay, H. A.; Côté, M. M. and Jin, Y. K. Geohazard investigations of permafrost and gas hydrates in the outer shelf and upper slope of the Canadian Beaufort Sea: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 24 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117601 Douglas, Thomas A. (U. S. Army Cold Regions Research and Engineering Laboratory, Fort Wainwright, AK); Hiemstra, C. A.; Bjella, Kevin; Jorgenson, M. T.; Newman, S.; Deeb, E. and Anderson, John. Using remote sensing and ground based measurements to identify vegetation-geomorphology patterns in permafrost: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 29 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117600 Eppler, J. (MDA Systems, Richmond, BC, Canada); Kubanski, M.; Sharma, J.; Busler, J.; Roger, J. and Allard, M. InSAR monitoring of transportation infrastructure in permafrost regions: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, 11 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115156 Flynn, David (KGS Group, Winnipeg, MB, Canada); Alfaro, Marolo; Graham, Jim and Arenson, Lukas U. Observed deformations of an existing highway embankment on degrading permafrost: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 10 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119218 Ghias, Masoumeh Shojae (Université Laval, Quebec, QC, Canada); Therrien, René; Molson, John and Lemieux, Jean-Michel. Numerical simulations of coupled groundwater flow and heat transport incorporating freeze/thaw cycles and phase change in a continuous permafrost environment: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 10 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119211 Gilbert, Graham L. (University Centre in Svalbard, Geology Department, Svalbard and Jan Mayen Islands); Christiansen, Hanne H. and Neumann, Ullrich. Coring of unconsolidated permafrost deposits; methodological successes and challenges: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 8 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119183 Grandmont, Katerine (Northern Climate ExChange, Yukon Research Centre, Canada); Roy, Louis-Philippe; de Grandpré, Isabelle; Fortier, Daniel; Benkert, Bronwyn and Lewkowicz, Antoni. Impact of land cover disturbance on permafrost landscapes; case studies from Yukon communities: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 39 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119170 Gruber, Stephan (Carleton University, Ottawa, ON, Canada); Burn, Christopher R.; Arenson, Lukas; Geertsema, Marten; Harris, Stuart; Smith, Sharon L.; Bonnaventure, Philip and Benkert, Bronwyn. Permafrost in mountainous regions of Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 65 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117565 Hayley, Don W. Science to technology; the importance of understanding the fundamentals of permafrost science for engineering practicing in the north: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 18 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119198 Kurchatova, Anna N. (Tyumen State Oil and Gas University, Tyumen, Russian Federation) and Rogov, Victor V. Hydrocarbon seepage and formation of authigenic minerals in the permafrost of West Siberia: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 14 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119204 Lanouette, Florence (Laval University, Quebec, QC, Canada); Doré, Guy; Fortier, Daniel and Lemieux, Chantal. Influence of snow cover on the ground thermal regime along an embankment built on permafrost; in-situ measurements: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119166 Lapalme, Caitlin M. (University of Ottawa, Department of Geography, Ottawa, ON, Canada); Lacelle, Denis; Davila, Alfonso F.; Pollard, Wayne; Fortier, Daniel and McKay, Chritopher P. Cryostratigraphy of near-surface permafrost in University Valley, McMurdo dry valleys of Antarctica: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 33 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117598 LeBlanc, Anne-Marie (Geological Survey of Canada, Canada); Short, Naomi; Mathon-Dufour, Valérie; Allard, Michel; Tremblay, Tommy; Oldenborger, Greg A. and Chartrand, Jason. DInSAR seasonal surface displacement in built and natural permafrost environments, Iqaluit, Nunavut, Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, sketch map, 10 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119181 Lewkowicz, Antoni G. (University of Ottawa, Department of geography, Ottawa, ON, Canada); Tremblay, Martin and Montgomery, Kelly. Development of a new CSA standard for moderating the effects of permafrost degradation on existing building foundations: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 3 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119185 McKenna, Karen (CryoGeographic Consulting, Whitehorse, YT, Canada); Davies, Kam; Smith, Scott and Gasser, Pierre-Yves. Agricultural adaptations to changing permafrost conditions in southern Yukon: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, 17 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119193 Morse, P. D. (Geological Survey of Canada, Natural Resources Canada, Ottawa, ON, Canada); Woilfe, S. A.; Kokelj, S. V. and Gaanderse, A. J. R. Permafrost occurrence in subarctic forests of the Great Slave region, Northwest Territories, Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 30 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117550 Niu Fujun (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Liu Minghao; Wu Libo; Cheng Guodong and Wu Qingbai. Deformation characteristics of the main embankments of the Qinghai-Tibet Railway in permafrost regions: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 15 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117569 O'Neill, H. B. (Carleton University, Department of Geography and Environmental Studies, Ottawa, ON, Canada) and Burn, C. R. Permafrost degradation adjacent to snow fences along the Dempster Highway, Peel Plateau, NWT: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, 25 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117567 Pollard, Wayne (McGill University, Department of Geography, Montreal, QC, Canada); Ward, Melissa and Becker, Michael. The Eureka Sound lowlands; an ice-rich permafrost landscape in transition: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch maps, 26 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117599 Rabus, Bernhard (3vGeomatics, Vancouver, BC, Canada); Leighton, Jon; Lefort, Alex and Avey, Colin. Advanced InSAR for permafrost related ground motion: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch maps, 6 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115175 Romanovsky, Vladimir E. (University of Alaska, Geophysical Institute, Fairbanks, AK); Cable, William L. and Kholodov, Alexander L. Changes in permafrost and active-layer temperature along an Alaskan permafrost-ecological transect: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 20 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117608 Rudy, A. C. A. (Queen's University, Department of Geography, Kingston, ON, Canada); Lamoureux, S. F.; Holloway, J. E.; Lafrenière, M. J.; Kokelj, S. V.; Segal, R.; Lantz, T. C.; Fraser, R. H. and Smith, I. R. Watershed delineation in areas of permafrost disturbance on eastern Banks Island, NWT; a geomatics approach for predicting water quality impacts: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 22 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115172 Schoeneich, Philippe (Université de Grenoble-Alpes, Institut de Géographie Alpine, Grenoble, France); Krysiecki, Jean-Michel; Mingrat, Ludovic and Huwald, Hendrik. DTS ground temperature measurements in mountain permafrost; the 2Alpes-3065 borehole (French Alps): in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, 19 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119197 Sheinkman, Vladimir (Tyumen State Gas and Oil University, Tyumen, Russian Federation) and Melnikov, Vladimir. Evidence in favor of that over the Pleistocene cryodiversity in northwestern Siberia developed as interaction of permafrost and mountain glaciers but not of ice sheets: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 12 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117612 Sherstiukov, Artem (All Russian Research Institute of Hydrometeorological Information, World Data Centre, Obninsk, Russian Federation) and Streletskiy, Dmitry. Spatial variability of soil temperature and active-layer thickness in the permafrost regions of Russia during the last fifty years: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 39 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119196 Sliger, M. (University of Montreal, Department of Geography, Montreal, QC, Canada); Fortier, D.; deGrandpré, I. and Lapointe-Elmrabti, L. Incidence of late Pleistocene-Holocene climate on the concurrent landscape and permafrost development of the Beaver Creek region, southwestern Yukon, Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch maps, 35 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115170 Smith, Sharon L. (Geological Survey of Canada, Ottawa, ON, Canada); Lewkowicz, Antoni G.; Duchesne, Caroline and Ednie, Mark. Variability and change in permafrost thermal state in northern Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 12 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117571 Smith, Sharon L. (Geological Survey of Canada, Ottawa, ON, Canada); Lewkowicz, Antoni G.; Ednie, Mark; Duguay, Maxime A. and Bevington, Alexandre. Characterization of permafrost thermal state in the southern Yukon: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 23 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117561 Stephani, Eva (Golder Associates, Anchorage, AK); Musial, Mark and Anderson, Steve. Reclamation of material sites in continuous permafrost of Alaska; an example of groundwater flow between pits: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 18 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119186 Streletskiy, Dmitry (George Washington University, Department of Geography, Washington, DC); Shiklomanov, Nikolay; Kokorev, Vasily and Anisimov, Oleg. Arctic cities, permafrost and changing climatic conditions: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 8 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119219 Veuille, Sabine (University of Montreal, Geography Department, Montreal, QC, Canada); Fortier, Daniel; Verpaelst, Manuel; Grandmont, Katerine and Charbonneau, Simon. Heat advection in the active layer of permafrost; physical modelling to quantify the impact of subsurface flow on soil thawing: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 5 tables, 27 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115155 Wolfe, S. A. (Geological Survey of Canada, Ottawa, ON, Canada); Morse, P. D.; Hoeve, T. E.; Sladen, W. E.; Kokelj, S. V. and Arenson, L. U. Disequilibrium permafrost conditions on NWT Highway 3: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 33 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117604 Wolfe, S. A. (Geological Survey of Canada, Ottawa, ON, Canada) and Morse, P. D. Holocene lake-level recession, permafrost aggradation and lithalsa formation in the Yellowknife area, Great Slave Lowland: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 18 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117610 Xie Changwei (Chinese Acadmey of Sciences, Cold & Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Gough, William A.; Zhao Lin and Wu Tonghua. Estimating annual apparent thermal diffusivity in permafrost using temperature times series on the Qinghai-Tibet Plateau, China: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 13 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15120692 Iijima, Yoshihiro (Japan Agency for Marine-Earth Science and Technology, Japan); Abe, Konomi; Ise, Hajime and Masuzawa, Tadashi. Detection of regional extent of permafrost thawing and waterlog damage area in boreal forest in eastern Siberia during w [abstr.]: in Japan Geoscience Union meeting 2014, Abstract - Japan Geoscience Union Meeting, 2014, 2014. Meeting: Japan Geoscience Union meeting 2014, April 28-May 2, 2014, Yokohama, Japan. Accessed on Jan. 14, 2015.

Wet climate with largely increased in rainfall during summer and snow accumulation during winter had perennially continued since 2004 in eastern Siberia. Soil moisture in the active layer had been rapidly increased corresponding with thawing permafrost near the surface during following years. The perennially water-logged active layer furthermore exacerbated the boreal forest habitat, namely withered and dead forests widely extended in this region. In the present study, we have attempted to extract the region of degraded boreal (larch) forest based on the analysis of satellite data (ALOS-AVNIR2 and PALSAR) in the left and right banks of the central Lena River Basin near Yakutsk, along with expansion of the water-logged forest floor in relation to permafrost degradation.

URL: http://www2.jpgu.org/meeting/2014/PDF2014/2014ALL_e.pdf

15120708 Kondo, Miyuki (National Institute for Environmental Studies, Japan); Uchida, Masao; Utsumi, Motoo; Iwahana, Go; Yoshikawa, Kenji; Iwata, Hiroki; Harazono, Yoshinobu; Nakai, Taro; Tanabe, Kiyoshi and Shibata, Yasuyuki. Estimate of permafrost organic carbon balance in Alaskan boreal and tundra ecosystems using natural radiocarbon tracer [abstr.]: in Japan Geoscience Union meeting 2014, Abstract - Japan Geoscience Union Meeting, 2014, 2014. Meeting: Japan Geoscience Union meeting 2014, April 28-May 2, 2014, Yokohama, Japan. Accessed on Jan. 14, 2015.

The high-latitude regions, where a serious warming is expected, currently store large amounts of soil organic carbon in active-layer soils and permafrost, accounting for nearly half of the global belowground organic carbon pool. Despite the importance of these regions in the present carbon cycle, the soil C fluxes and budget are still only poorly known. Here, we use radiocarbon as the tool for quantifying the C balance of the inputs and decomposition in tundra and boreal soil. We evaluated the C inputs (I) and decomposition rates (k, inverse of turnover time) and net C accumulation (CA), using ¹⁴C approaches. Tundra and boreal soils show different patterns of depth distribution and C storage. Cumulative organic carbon stocks in boreal forest are 5.3 and 19.2 kgCm^-2, in surface organic layer (0-25 cm), and deep organic and mineral layers (25-70 cm), respectively. Large annual C input (0.25 kgCm^-2 yr^-1) and relatively slow decomposition (27 years) lead to rapid CA (0.05 kgCm^-2 yr^-1) in surface organic layer in boreal forest. Deep organic and mineral layers including near-surface permafrost show slower rate of input (0.03 kgCm^-2 yr^-1) and turnover (617 years) and CA about 20 times slower (0.003 kgCm^-2 yr^-1) than surface organic layer. Decomposition organic matter (Rh), which in accord with C losses from both surface and subsurface -1 layers, was 0.23 kgCm^-2 yr. This value agreed well with Rh (0.23 kgCm^-2 yr^-1) simulated by process-based models that simulate the biogeochemical and hydrologic cycle, where Rh averaged 45% of ecosystem respiration and 59% of soil respiration. In contrast, large amount of SOC (36.4 kg m^-2) have accumulated over millennia (turnover time: 4540 yrs) below the thin organic layer in tundra. The CA of mineral layer and permafrost is close to zero (0.003 kgCm^-2 yr^-1), and Rh is 0.008 kgCm^-2 yr^-1. Our radiocarbon data show that the most SOC in tundra soil was mode of stabilizing OC by permafrost and steady-state SOC stocks under current C balance.

URL: http://www2.jpgu.org/meeting/2014/PDF2014/2014ALL_e.pdf

15120697 Sueyoshi, Tetsuo (Japan Agency for Marine-Earth Science and Technology, Japan); Saito, Kazuyuki; Ishikawa, Mamoru; Harada, Koichiro and Iwahana, Go. Changes of permafrost environment and the response to the long term climate change [abstr.]: in Japan Geoscience Union meeting 2014, Abstract - Japan Geoscience Union Meeting, 2014, 2014. Meeting: Japan Geoscience Union meeting 2014, April 28-May 2, 2014, Yokohama, Japan. Accessed on Jan. 14, 2015.

Permafrost is soil and sediment that is frozen more than two consecutive years, most of which is located in high latitudes. Ground ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of the ground material. Permafrost accounts for 0.022% of total water and exists in 24% of exposed land in the Northern Hemisphere. permafrost contains 1700 billion tons of organic material equaling almost half of all organic material in all soils. This pool was built up over thousands of years and is only slowly degraded under the cold conditions in the Arctic. Most of the permafrost existing today formed during cold glacial periods, and has persisted through warmer interglacial periods, including the Holocene. The time scale of the thermal process is different depending on the depth (i.e. distance from the ground surface) and the soil thermal properties, while the vegetation processes such as accumulation of organic material have yet different time scales. In this presentation, we discuss those complex character of permafrost and show the outlook on the future research needs, showing an example study on the relationship between permafrost distribution and long-term climate change.

URL: http://www2.jpgu.org/meeting/2014/PDF2014/2014ALL_e.pdf

15120718 Yonemura, Seiichiro (National Institute for Agro-Environmental Sciences, Japan); Uchida, Masao and Kondo, Miyuki. Automatic measurement of gas emission/uptake of Alaskan permafrost soils [abstr.]: in Japan Geoscience Union meeting 2014, Abstract - Japan Geoscience Union Meeting, 2014, 2014. Meeting: Japan Geoscience Union meeting 2014, April 28-May 2, 2014, Yokohama, Japan. Accessed on Jan. 21, 2015.

The release of carbon from the decomposition of organic matters in permafrost soils are very important for the acceleration of global warming. We applied our dynamic system to Alaskan soils and measured temperature dependence of gas (CO2, CH4, N2O, NO, H2, CO) emission/uptake. The Four core samples were placed on petri-dishes which were put into chambers where temperature was controlled. CO2 emission from soils showed variations different from sample to sample. Even at -5C, CO2 emissions were observed. From the time series of CO2 emission rates, we estimated Q10 values. Q10 values were similar between 5-15C and 15 and 25C. Some soils also temperature-dependently emit NO, CO and N2O.

URL: http://www2.jpgu.org/meeting/2014/PDF2014/2014ALL_e.pdf

15114936 Campbell, Seth (U.S. Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory, Hanover, NH). Influences of terrain and vegetation on permafrost distribution; case studies from Tanana Flats and 12-Mile Lake, Alaska [abstr.]: in Geological Society of America, Northeastern Section, 50th annual meeting, Abstracts with Programs - Geological Society of America, 47(3), p. 108, March 2015. Meeting: Geological Society of America, Northeastern Section, 50th annual meeting, March 23-25, 2015, Bretton Woods, NH.

Links exist between permafrost distribution and latitude, climate warming, vegetation succession, surface slope, aspect, hydrology, geology, winter snow cover, and forest fire activity. However, these relationships are difficult to quantify which results in only a coarsely mapped distribution (depth and extent) of permafrost in Alaska. Alaskan permafrost and ground ice act as a significant greenhouse gas sink and have tremendous impacts on local geotechnical engineering (e.g. roads, oil pipelines, polar structures). Therefore, an ultimate goal in Alaskan permafrost research is to develop accurate predictive estimates of permafrost distribution relative to climate change scenarios. Herein, I compare available digital terrain data and satellite imagery to ground-penetrating radar and galvanic resistivity surveys used to map permafrost distribution in Tanana Flats near Fairbanks and surrounding 12-Mile Lake within the drainage corridor of the Yukon River, Alaska. Results show qualitative relationships between permafrost distribution mapped with geophysical surveys and surface slope, aspect, and modeled solar radiation determined from high resolution digital terrain data. Vegetation biomass and vegetation type determined from remotely sensed data also show qualitative relationships to permafrost extent. Quantitative analysis show similar, albeit weaker, trends between permafrost distribution and each of these variables, likely because numerous variables impact permafrost at each study location. This study indicates that the combination of digital terrain, remote sensing, and geophysical data may provide a robust dataset for determining current extent of permafrost and estimating changes in extent with respect to future climate change scenarios.

15118576 Alexander, H. D. (University of Texas, Brownsville, Brownsville, TX); Mack, M. C.; Natali, S.; Loranty, M. M.; Davydov, S. P. and Zimov, N. Changing Boreal fire regimes; impacts on permafrost soils and forest succession in Siberian larch forests [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11B-0558, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Fire activity has increased across the boreal forest biome in conjuction with climate warming and drying. Because these forests contain a large proportion of global terrestrial carbon (C) stocks, there has been great interest in understanding feedbacks between a changing fire regime and climate warming. An important mechanism by which increased fire activity may alter boreal C balance is by consuming the soil organic layer (SOL). Fire removal of the SOL may alter germination microsites and tree recruitment, thereby altering forest successional trajectories and C accumulation and storage. In permafrost soils, loss of the insulating SOL can increase soil temperature and active layer depth, impacting growth and survival conditions for both soil microbes and vegetation. To assess fire severity effects on permafrost soils and tree recruitment, we conducted plot-level experimental burns in July 2012 in a larch forest near Cherskii, Siberia. We achieved four burn severity treatments based on residual SOL depths: control, low (> 8 cm), moderate (5-8 cm), and high severity (2-5 cm). For two growing seasons post-fire, we measured thaw depth, soil moisture, and soil temperature. We sowed larch seeds in fall 2012 and 2013 and quantified seedling establishment and vegetation re-growth for two growing seasons. Immediately post-fire, thaw depth increased rapidly with increasing fire severity, and this trend has persisted for two years. In 2013 and 2014, thaw depth was ~ 40 cm deeper in high severity plots compared to controls, likely due to lower summer soil insulation, higher black char cover, and higher surface soil temperatures. We observed little to no larch recruitment in unburned and low severity plots, but new seedling density was ~5 seedlings m-2 in moderate and high severity plots, which had low cover of other vegetation types and high soil moisture. Findings suggest that increased fire severity may increase larch recruitment and provide favorable soil conditions for tree growth. As a consequence, forest density and potential to accumulate and store C in tree biomass will likely increase. The balance between C lost via fire and microbial respiration and C gained due to changes in forest stand structure will determine whether boreal forests represent a C pool or sink under changing fire regimes.

15112002 Collier, Nathaniel (Oak Ridge National Laboratory, Oak Ridge, TN); Bisht, G. and Kumar, Jitendra. Challenges to large-scale simulations of permafrost freeze-thaw dynamics [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC33A-0480, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

In an effort to model the dynamics of the permafrost freeze and thaw process in the Alaskan tundra, we have implemented a finite volume method which approximates the evolution of a coupled surface/subsurface mass and energy balance within PFLOTRAN--an open source, state-of-the-art massively parallel subsurface flow and reactive transport code. While this system is studied in the literature at one scale, we encounter many undocumented pitfalls as we exercise the model at high resolution and force using realistic datasets from the field sites. These realistic simulations for field sites near Barrow, Alaska expose the model to a wide range of moisture and thermal states that are not tested in published studies. For example, the conventional upwinding of the relative permeability used in the Darcy flux computation can yield a flow into a frozen cell. We also find that infiltration, sources, and sinks must be carefully regulated as flow into frozen portions of the domain, or out of dry or frozen regions can cause unphysical states in the simulation which cause failure. Many straight-forward solutions are not smooth which produce discontinuities in the Jacobian of the nonlinear residual. These difficulties represent a current hurdle to running large-scale permafrost dynamics simulations. We describe these challenges and present approaches to overcoming them in the pursuit of a scalable scheme.

15120830 Gangodagamage, Chandana (Los Alamos National Laboratory, Los Alamos, NM); Rowland, Joel; Hubbard, Susan S.; Brumby, Steven; Liljedahl, Anna; Wainwright, Haruko; Sloan, Victoria L.; Altmann, Garrett; Skurikhin, Alexei; Shelef, Eitan; Wilson, C. J.; Dafflon, Baptiste; Peterson, John; Ulrich, Craig; Gibbs, A.; Tweedie, Craig; Painter, Scott and Wullschleger, S. D. Predicting/extrapolating active layer thickness using statistical learning from remotely-sensed high-resolution data in arctic permafrost landscapes; improved parameterization of ice-wedge polygons from LiDAR/WorldView-2 derived metrics [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract EP31A-3517, illus., December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Landscape attributes that vary with micro-topography, such as active layer thickness (ALT) in ice-wedge polygon ground, are labor-intensive to document in the field at large spatial extents, necessitating remotely sensed methods. Robust techniques to estimate ALT over large areas would improve understanding of coupled dynamics between permafrost, hydrology and landsurface processes, and improve simulations of the rate and timing of release of soil carbon from permafrost settings. In particular, it would provide critically needed data to parameterize and initialize soil property information in permafrost models and evaluate model predictions for large, complex domains. In this work, we demonstrate a new data fusion approach using high-resolution remotely sensed data for estimating cm scale ALT in a 5 km² area of ice-wedge polygon terrain in Barrow, Alaska. We used topographic (directed distance, slope, wavelet-curvature) and spectral (NDVI) metrics derived from multisensor data obtained from LiDAR and WorldView-2 platforms to develop a simple data fusion algorithm using statistical machine learning. This algorithm was used to estimate ALT (2 m spatial resolution) across the study area. A comparison of the estimates with ground-based measurements documented the accuracy (±4.4 cm, r2=0.76) of the approach. Our findings suggest that the broad climatic variability associated with warming air temperature will govern the regional averages of ALT, but the smaller-scale variability could be controlled by local eco-hydro-geomorphic variables. This work demonstrates a path forward for mapping subsurface properties over large areas from readily available remote sensing data. Methodology of Mapping and Characterization Polygons: We convolve LiDAR elevations with multiscale wavelets and objectively chose appropriate scales to map interconnected troughs of high- and low-centered polygons. For the ice wedges where LiDAR surface expressions (troughs) are not well developed, we used a Delaunay triangulation to connect the ice-wedge network and map the topologically connected polygons. Polygon slopes and curvatures as a function of DD were used to develop a microtopographic classification scheme for rims/elevated ridges (Zone 1), centers (Zone 2), and troughs (Zone 3) in both high- and low-centered polygon.

15114371 Godsey, S. (Idaho State University, Idaho Falls, ID); Rushlow, C. R. and Harms, Tamara. Hydrologic connectivity in headwater catchments underlain by continuous permafrost; hydrological, thermal and biogeochemical patterns [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H31F-0674, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Hydrologic connectivity within headwater fluvial networks depends largely on subsurface patterns of moisture. Dynamic subsurface properties that control those patterns can vary widely and are poorly constrained in many systems. However, subsurface conditions change seasonally in a predictable way in catchments underlain by permafrost due to increasing thaw throughout the summer season, and those changes can be systematically measured. Zero-order linear flow features known as water tracks are found in upland permafrost hillslopes and occupy up to 35% of the landscape. Water tracks often connect to downstream fluvial systems via subsurface pathways, but those connections are poorly understood. We present data from six water tracks underlain by permafrost in northern Alaska. We improve our understanding of water tracks and their connections to downstream fluvial systems in two ways. First, we compare the fraction of snow and rain comprising flows in water tracks and the downstream systems to which they connect, and we discuss the resulting constraints on biogeochemical fluxes in these systems. Second, we examine the subsurface controls on water track connectivity patterns by characterizing the water tracks' thermal signatures. We demonstrate that a shallow unfrozen layer permits subsurface flow to continue below a surface frozen layer for up to 6 months after air temperatures drop below freezing, enhancing fall and winter water track downstream connectivity. Because winter air temperatures are projected to increase and become more variable, we examine the role of freeze-thaw events on hydrologic connectivity: some water tracks are less responsive to rapid air temperature changes than surrounding hillslopes. At these sites, soils inside the water tracks remain frozen and impermeable for ~10 more days each year and cycle through fewer freeze-thaw cycles than the same soils outside water tracks. Some shallow soils outside some water tracks freeze and thaw up to 3-fold more times per year than water track soils. We discuss how thermal responses of water tracks influence downstream biogeochemical fluxes in the dynamic freeze-thaw periods.

15118602 Heikoop, J. M. (Los Alamos National Laboratory, Los Alamos, NM); Throckmorton, H.; Newman, B. D.; Perkins, G.; Gard, M.; Iversen, C. M.; Wilson, C. J. and Wullschleger, S. D. Isotopic identification of nitrate sources and cycling in Arctic tundra active layer soils and permafrost [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC13C-0658, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

The effect of nitrogen cycling on release of carbon from tundra ecosystems is being studied as part of the US Department of Energy Next Generation Ecosystem Experiment - Arctic project. Sampling and analysis of active layer soil water at the Barrow Environmental Observatory (Alaska, USA) was performed in ancient drained thaw lake basins (DTLBs), drainages, and in polygonal terrain associated with inter-DTLB tundra. Within active layer soils, nitrate was most commonly found above analytical limits of detection in pore water from the unsaturated centers of high-centered polygons. Nitrate has also been detected, though less frequently, in soil water immediately above the frost table of an ancient (14C age of 2000 - 5500 BP) DTLB and in a small drainage adjacent to high-centered polygonal terrain. Nitrate from high-centered polygons had d15N ranging from -9.2 to +8.5 ppm and d18O ranging from -8.4 to +1.4 ppm. The d15N isotopic range is consistent with microbial mineralization and nitrification of reduced nitrogen sources including ammonium, dissolved organic nitrogen, and soil organic nitrogen. The range in d18O of nitrate is also consistent with nitrification based on the d18O of site waters. No evidence for an atmospheric nitrate signal, as defined by d15N and d18O of nitrate in snow and snowmelt, is seen. In contrast, nitrate in permafrost appears to be a mixture of pre-industrial atmospheric nitrate (with higher d15N than modern atmospheric nitrate) and nitrate that is microbial in origin. Massive ice wedges appear to contain larger proportions of snowmelt (based on d18O of ice) and atmospheric nitrate, whereas textural ice appears to contain a greater proportion of summer precipitation and microbially-derived nitrate. Nitrate from the ancient DTLB and drainage samples also has isotopic signatures that appear to represent a mixture of pre-industrial atmospheric nitrate and nitrate from microbial nitrification, and may, at least in part, be derived from degraded permafrost.

15118624 Jarsjo, J. (Stockholm University, Physical Geography & Quaternary Geology, Stockholm, Sweden); Tornqvist, R.; Bring, A.; Pietron, J.; Rogberg, P.; Asokan, S. M. and Destouni, G. Impacts of hydro-climatic change, permafrost thaw and industrial pressures in the Lake Baikal drainage basin (Mongolia and Russia) [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC13K-07, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

The large Arctic river Yenisei and Lake Baikal with its unique ecosystem containing endemic species are influenced by on-going hydro-climatic changes in the Lake Baikal Drainage Basin. The latter extends from southern Siberia into northern Mongolia, and contains one of the word's larger mining regions, for instance with mining of gold, silver, copper and coal. Recognizing that changing hydro-climatic conditions in the basin may lead to changed loading pattern of anthropogenic substances to Lake Baikal and Yenisei, we aim at identifying long-term historic and projected future hydro-climatic trends in this basin and their (possible) impacts. The analyses are based on hydro-climatic observations and the output 22 Earth System Models (ESMs) of the Coupled Model Intercomparison Project, Phase 5 (CMIP5). Observations show that warming rates of the basin were twice as high as the global average during past 70 years. Decreased intra annual variability of river discharge over this period indicates basin-scale permafrost degradation. CMIP5 ensemble projections show further future warming, implying continued permafrost thaw. Most individual models as well as the CMIP5 ensemble mean result indicate increased runoff in the future. However the spread of individual model results is large. Parallel results show that such increased runoff can considerably increase the annual riverine sediment loads and consequently the loading of contaminants that are attached to the sediments, in particular downstream of mining sites. More generally, this exemplifies how long-term hydro-climatic changes, permafrost thaw, and industrial pressures may interact in increasing the bioavailability of contaminants in downstream recipients.

15116945 Jones, J. (University of Alaska, Fairbanks, Fairbanks, AK) and Harms, T. Long-term trends in stream biogeochemistry and hydrology in watersheds underlain with discontinuous permafrost in the boreal forest of Alaska [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H12D-06, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

In the boreal forest of Alaska, watersheds are commonly underlain with discontinuous permafrost, which has a dominant control on catchment hydrology and the resulting input of dissolved organic matter (DOM) and nutrients into streams. Much of the permafrost is near the point of thawing, which will alter the hydrologic connections between watersheds and streams. Wildfires are also common in the boreal forest of Alaska and can impact streams hydrology and nutrients. Wildfires have been increasing in frequency and severity with recent warming, and have the potential to alter the delivery of DOM and nutrients to streams. Together, permafrost and wildfires interact to regulate hydrology and material inputs into streams. We have been measuring stream flow since 1980, and water chemistry since 2000 in streams draining sub-catchments with varying extents of underlying permafrost in the Caribou-Poker Creeks Research Watershed in interior Alaska. Across sub-catchments, streams draining watersheds with extensive permafrost have flashier hydrographs compared to streams draining catchments with little permafrost. Coupled to patterns in flow, DOM concentration is greatest in streams draining watersheds with large extents of underlying permafrost, whereas nitrate concentration tends to be highest in streams draining lower permafrost catchments. Following a wildfire in the CPCRW, stream DOM concentration significantly declined compared with a control stream, suggesting that the fire either resulted in a loss of soil organic matter or altered hydrologic flowpaths through catchments. With climatic warming, permafrost thaw and changing fire frequency will interact to determine DOM concentration and composition in streams of the boreal forest, and will have important impacts on the coupling between DOM decomposition and nutrient cycling.

15111995 Kerimov, Ali G. (Engineering Scientific Company "Ecofoundations", Norilsk, Russian Federation); Grebenets, V. I.; Streletskiy, D. A.; Shiklomanov, N. I. and Nyland, K. E. Evolution of permafrost landscapes under technogenic impacts [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC31B-0459, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Economic development of Russian Northern Regions on permafrost resulted in a new pattern of geocryological conditions, different from natural environment. This pattern is characterized by drastic landscape transformations; changes of heat and mass transfer in the permafrost/atmosphere system; and by engineering and technical pressure upon the permafrost, leading to alteration of its physical, thermal and mechanical properties. In the northern cities this causes increase of ground temperature and intensification of hazardous cryogenic processes in areas under engineering development, reducing stability of geotechnical environment. For example, facility deformations in Norilsk in the last 15 years, became much more abundant than these revealed throughout the previous 50 years. Increase in accident risk for facilities (pipelines, industrial enterprises, etc.) enhances the technogenic pressure on permafrost of the territories under development, leading to the new milestone of changes in permafrost, i.e. to creation of a new set of geocryological conditions. Cryogenic processes within the urban cryolithozone are seldom similar with these under the natural conditions: they either occur more intensively or, vice versa, attenuate under technogenic impacts, new cryogenic processes and phenomena occur, which have not been typical for a given region hitherto. A geographical distribution, evolution and other features of cryogenic processes differ considerably from natural conditions or are unprecedented at all. Peculiar natural-technogenic geocryological complices (NTGC) are formed in the urban centers, which are remarkable by the vector of permafrost evolution, by the set of cryogenic processes, by temperature trends and the other characteristics. NTGC types depend on initial natural settings and on kinds, intensity and duration of technogenic pressure. Our field surveys of permafrost and geological conditions resulted in mapping of 17 NTGC types in Norilsk, 11 types in Yamburg gas field, and 32 types along gas and oil pipelines in the north of Western Siberia. NTGC dynamics, depending on climate change, the scale of urban system, on the set of its elements and on duration of impact upon nature, and on degree of stability of natural permafrost, attracts the particular interest.

15118590 Lafreniere, M. J. (Queen's University, Geography, Kingston, ON, Canada); Louiseize, N. L.; Lamoureux, S. F. and Hastings, M. G. Permafrost disturbance impacts on dissolved ion loads and nitrogen dynamics [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11F-07, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Physical disturbance (slope failure) and thermal perturbation (deep thaw) of the active layer alter the physical hydrology and the dissolved loads of solutes and nutrients of arctic watersheds and downstream water bodies, however the seasonality and duration of these changes, and the processes responsible for them, are poorly understood. To examine these dimensions of permafrost change, we investigated the seasonal fluxes of major ions and dissolved N species from small catchments that were affected by recent slope failures. The catchments represent a range of disturbance extent and hydrological connectivity, including an undisturbed control catchment. Key differences in the impacts of slope disturbance on the fluvial export of major ions, and nitrogen from these headwater catchments were observed. The export of ions increased for all streams (disturbed and undisturbed) in response to deep thaw in warm years. However, the impact of physical disturbance was largely limited to increased ion concentrations late in the season when baseflow was driven by rainfall and soil water drainage. In contrast, nitrate (NO3-) concentrations were substantially affected by physical disturbance. A comparison of a disturbed and undisturbed catchment shows the two streams had similar concentrations of all dissolved N prior to slope failure, yet five years following failure, NO3- concentrations in the disturbed watershed were two orders of magnitude higher than in the undisturbed catchment. NO3- was especially high following late season rainfall and isotopic evidence shows that late season NO3-is not from rainfall but microbially produced (mineralized). Results indicate that the impact of disturbance on ion and N loads is limited by discharge and hydrological connectivity of the disturbed areas, that the drainage of upper permafrost (soils below normal active layer depth) is the likely source of enhanced ion and mineralized NO3-, and that impacts are evident several years after disturbance.

15112074 Livezey, Marina M. (NOAA Headquarters, Washington, DC); Jonassen, Rachael G.; Horsfall, Fiona M. C.; Jafarov, Elchin E. and Schaefer, Kevin M. Towards NOAA forecasts of permafrost active layer thickness [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC53C-0543, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

NOAA's implementation of its 2014 Arctic Action Plan (AAP) lacks services related to permafrost change yet the Interagency Working Group on Coordination of Domestic Energy Development and Permitting in Alaska noted that warming permafrost challenges land-based development and calls for agencies to provide focused information needed by decision-makers. To address this we propose to link NOAA's existing seasonal forecasts of temperature and precipitation with a high-resolution model of the thermal state of permafrost (Jafarov et al., 2012) to provide near-term (one year ahead) forecasts of active layer thickness (ALT). Such forecasts would be an official NOAA statement of the expected thermal state of permafrost ALT in Alaska and would require: (1) long-term climate outlooks, (2) a permafrost model, (3) detailed specification of local spatial and vertical controls upon soil thermal state, (4) high-resolution vertical measurements of that thermal state, and (5) demonstration of forecast skill in pilot studies. Pilot efforts should focus on oil pipelines where the cost can be justified. With skillful forecasts, engineers could reduce costs of monitoring and repair as well as ecosystem damage by positioning equipment to more rapidly respond to predicted disruptions.

15118729 Quinlan, R. (York University, Toronto, ON, Canada); Delaney, S.; Lamoureux, S. F.; Kokelj, S. V. and Pisaric, M. F. Paleoecological inferences of recent alluvial damming of a lake basin due to retrogressive permafrost thaw slumping [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract PP21B-1338, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Expected climate impacts of future warming in the Arctic include thawing of permafrost landscapes in northern latitudes. Thawing permafrost is expected to have major consequences on hydrological dynamics, which will affect the limnological conditions of Arctic lakes and ponds. In this study we obtained a sediment core from a small lake (informally named "FM1") near Fort McPherson, Northwest Territories, Canada, with a large retrogressive thaw slump (nearly 1 kilometer in diameter) within its catchment. A radiocarbon date from the base of the FM1 sediment core suggests the lake formed between 990-1160 Cal AD. The analysis of aerial photographs indicate the thaw slump initiated between 1970-1990, and sediment geochemistry analysis indicated major changes in sediment content at 54-cm sediment core depth. Analyses of subfossil midge (Chironomidae) fossils inferred that, pre-slump, lake FM1 was shallow with a large bog or wetland environment, with midge assemblages dominated by taxa such as Limnophyes and Parametriocnemus. Post-thaw midge assemblages were dominated by subfamily Chironominae (Tribe Tanytarsini and Tribe Chironomini) taxa, and the appearance of deepwater-associated taxa such as Sergentia suggests that lake FM1 deepened, possibly as a result of alluvial damming from slump materials washing into the lake near its outlet. Most recent stratigraphic intervals infer a reversion back to shallower conditions, with a slight recovery of bog or wetland-associated midge taxa, possibly due to rapid basin infilling from increased deposition rates of catchment-derived materials. Results emphasize that there may be a variety of different outcomes to Arctic lake and pond ecosystems as a result of permafrost thawing, contingent on system-specific characteristics such as slump location relative to the lake basin, and relative inflow and outflow locations within the lake basin.

15118633 Schaedel, C. (University of Florida, Ft Walton Beach, FL); Bader, M. K. F.; Schuur, E. A. G.; Bracho, R. G.; Capek, P.; de Baets, S. L.; Diakova, K.; Ernakovich, J. G.; Hartley, I. P.; Iversen, C. M.; Kane, E. S.; Knoblauch, C.; Lupascu, M.; Natali, S.; Norby, R. J.; O'Donnell, J. A.; Roy Chowdhury, T.; Santruckova, H.; Shaver, G. R.; Sloan, V. L.; Treat, C. C. and Waldrop, M. P. Quantifying the effect size of changing environmental controls on carbon release from permafrost-affected soils [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC14A-03, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

High-latitude surface air temperatures are rising twice as fast as the global mean, causing permafrost to thaw and thereby exposing large quantities of previously frozen organic carbon (C) to microbial decomposition. Increasing temperatures in high latitude ecosystems not only increase C emissions from previously frozen C in permafrost but also indirectly affect the C cycle through changes in regional and local hydrology. Warmer temperatures increase thawing of ice-rich permafrost, causing land surface subsidence where soils become waterlogged, anoxic conditions prevail and C is released in form of anaerobic CO2 and CH4. Although substrate quality, physical protection, and nutrient availability affect C decomposition, increasing temperatures and changes in surface and sub-surface hydrology are likely the dominant factors affecting the rate and form of C release from permafrost; however, their effect size on C release is poorly quantified. We have compiled a database of 24 incubation studies with soils from active layer and permafrost from across the entire permafrost zone to quantify a) the effect size of increasing temperatures and b) the changes from aerobic to anaerobic environmental soil conditions on C release. Results from two different meta-analyses show that a 10°C increase in temperature increased C release by a factor of two in boreal forest, peatland and tundra ecosystems. Under aerobic incubation conditions, soils released on average three times more C than under anaerobic conditions with large variation among the different ecosystems. While peatlands showed similar amounts of C release under aerobic and anaerobic soil conditions, tundra and boreal forest ecosystems released up to 8 times more C under anoxic conditions. This pan-arctic synthesis shows that boreal forest and tundra soils will have a larger impact on climate change when newly thawed permafrost C decomposes in an aerobic environment compared to an anaerobic environment even when accounting for the higher heat trapping capacity of CH4 over a 100-year timescale.

15111998 Semiletov, Igor P. (University of Alaska Fairbanks, Fairbanks, AK); Shakhova, N. E.; Pipko, Irina; Dudarev, O. and Charkin, A. Permafrost thaw and redistribution of carbon from lands and oceans to the atmosphere; the East Siberian region [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC31B-0463, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Unlike other oceans, the Arctic Ocean is completely surrounded by permafrost, which is being degraded at an increasing rate under warming conditions most pronounced in East Siberian region and Alaska. The thaw and release of organic carbon (OC) from Arctic permafrost is postulated to be one of the most powerful mechanisms causing the net redistribution of carbon from lands and oceans to the atmosphere. The East Siberian Arctic shelf (ESAS) is the world's largest continental shelf, containing more than 80% of the world oceans' subsea permafrost and the largest hydrocarbon reservoir on the planet, while the stability of this sequestered carbon, which exists primarily as CH4, is highly uncertain. This area is heavily influenced by subsea permafrost thaw, and CH4 seeps from subsea permafrost reservoirs under warming conditions. Various other phenomena influence the area, including coastal erosion, mostly caused by onshore permafrost/coastal ice complex thaw; the input of dissolved and particulate OC through the Lena, Indigirka, and Kolyma rivers. The ESAS is also of particular interest for its carbon-climate couplings because thawing of onshore and offshore permafrost leads to the CH4 and CO2 emission to the atmosphere. The overall goal of the current research is to provide a quantitative, observation-based assessment of the dynamics of different ESAS carbon cycle components with emphasize on the emission of CO2 and CH4 to the atmosphere under changing climatic and environmental conditions.

15112008 Streletskiy, D. A. (George Washington University, Washington, DC); Tananaev, Nikita; Tokarev, Igor and Shiklomanov, Alex I. Permafrost and hydrology in the high latitudes of Eurasia [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC34A-08, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Eurasia contributes three quarters of all terrestrial runoff to the Arctic Ocean and contains three out of four major Arctic rivers. River flow is an integrated characteristic reflecting numerous environmental characteristics and processes aggregated over large spatial domains. A significant increase in discharge during low-flow has been observed everywhere in the Eurasian pan-Arctic, while precipitation decreased over the same period. This increase was accompanied by a significant increase in air temperature. Over the permafrost regions climatic warming results in higher ground temperature, a deeper annual thaw propagation, degradation of the ice rich upper permafrost layers, and a longer thaw season. The thicker active layer has more ground water storage and regulating capacity for increased contribution to runoff during low flow periods. Melt water of the excess ground-ice near the permafrost surface also contribute to the increase in river runoff. The deeper active layer delays its freeze-up date in winter and this late active layer freeze-up and increased ground water storage result in greater contribution of subsurface water to the river system, especially in the winter season. Extensive fieldwork and analytical procedures were implemented to quantify the contribution of permafrost to river flow in small rivers of Siberia and to understand its relation to air temperature. The paper focuses on variability of various water inputs to a hydrological system across multiple scales in a series of watersheds located in the transition of tundra to forest landscapes in the Arctic. Stable isotopes of d18O and D were used used to trace the inputs of various sources (ground ice, snow, precipitation, ground water) in a river flow. Mixing of these sources results in isotopic composition that varies throughout the year. Heavy content of d18O and D was found during winter season and is attributed to ground water from permafrost taliks. Lighter values in spring are attributed to snow melt. Heavy isotope content during the summer is attributed to evaporation of already heavy summer precipitation.

15114211 Vonk, J. (Utrecht University, Utrecht, Netherlands). Carbon fluxes of inland and coastal waters in permafrost regions [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract EP51A-3511, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Circum-arctic frozen soils contain twice as much carbon as is currently present as greenhouse gases in the atmosphere. Ongoing climate warming causes frozen soils to thaw, making the carbon available for microbial processing. This can generate greenhouse gases (fueling further global warming), both at the thaw site, but also during lateral transport in inland and coastal waters. Aquatic systems are increasingly recognized as reactive transport systems, but are generally not included in quantitative assessments of the magnitude of the permafrost carbon feedback. Combined carbon fluxes from lateral transport and aquatic gas emission can however be an important component of the total ecosystem carbon budget in Arctic regions. Here I aim to give an overview of our current knowledge on riverine and coastal organic carbon fluxes in permafrost regions, what factors determine the degradability (i.e. potential greenhouse gas production) of this organic carbon, and how we expect this to change in the future.

15111997 Walker, D. A. (University of Alaska Fairbanks, Fairbanks, AK); Raynolds, M. K.; Kumpula, Timo; Shur, Y.; Kanevskiy, M. Z.; Kofinas, Gary; Leibman, M. O.; Matyshak, G. V.; Epstein, H. E.; Buchhorn, M.; Wirth, L. M. and Forbes, B. C. Rapid arctic transitions in relation to infrastructure and climate change; comparison of the permafrost and geoecological conditions in the Bovanenkovo gas field, Russia and the Prudhoe Bay oil field, Alaska [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC31B-0461, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Many areas of the Arctic are undergoing rapid permafrost and ecosystem transitions resulting from a combination of industrial development and climate change as summer sea ice retreats and abundant Arctic natural resources become more accessible for extraction. The Bovanenkovo Gas Field (BGF) in Russia and the Prudhoe Bay Oilfield (PBO) in Alaska are among the oldest and most extensive industrial complexes in the Arctic, situated in areas with extensive ice-rich permafrost. Ongoing studies of cumulative effects in both regions are part of the Northern Eurasia Earth-Science Partnership Initiative (NEESPI) and NASA's Land-Cover Land-Use Change (LCLUC) research. Comparative analysis is focused on changes occurring due to different climate, permafrost, land-use, and disturbance regimes in the BGF and PBO and along bioclimate transects that contain both fields. Documentation of the changes in relationship to the different geoecological and social-economic conditions will help inform management approaches to minimize the effects of future activities. We compare the area of disturbance in the two fields and some of the key differences in the permafrost conditions. Detailed remote sensing and geoecological mapping in both areas reveal major differences in permafrost conditions that have implications for total ecological function. At BGF, highly erodible sands and the presence of massive tabular ground ice near the surface contributes to landslides and thermo-denudation of slopes. At PBO, ice-wedge degradation is the most noticeable change, where thermokarst is expanding rapidly along ice-wedges adjacent to roads and in areas away from roads. Between 1990 and 2001, coincident with strong atmospheric warming during the 1990s, natural thermokarst resulted in conversion of low-centered ice-wedge polygons to high-centered polygons, more active lakeshore erosion and increased landscape and habitat heterogeneity. These geoecological changes have local and regional consequences to wildlife habitat, land-use, and infrastructure. A conceptual model describes how infrastructure-related factors, including road dust and roadside flooding, are contributing to more extensive thermokarst in areas adjacent to roads and gravel pads in the PBO.

15111986 Wilson, C. J. (Los Alamos National Laboratory, Los Alamos, NM); Hinzman, L. D.; Iwahana, G.; Lara, M. J.; Liljedahl, A.; Painter, S. L.; Romanovsky, V. E. and Wullschleger, S. D. Linking inundation patterns and dynamics in a permafrost landscape to hydrologic, thermal, biogeochemical and ecosystem processes [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC23G-08, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

The Arctic coastal plain is characterized by multi-scale geomorphic features including thaw lakes, drained thaw lake basins, and clusters of ice wedge polygons composed of troughs, centers, and rims. The topographic and subsurface properties of these features control the lateral and vertical drainage pathways of snow melt and precipitation as well as the spatial and temporal dynamics of standing water in the landscape. The Next Generation Ecosystem Experiment, NGEE-Arctic, project combines multi-scale in-situ and remote surface and subsurface observations that quantify the interactions between landscape structure, hydrology, the carbon cycle and energy balance of Arctic permafrost environments, with the aim of improving representation of Arctic ecosystem processes in global climate models. Data and models from the project show distinct relationships exist between the hydro-geomorphic features mapped on the ground and observed in remote sensing imagery, and the measured in-situ thermal, biogeochemical and ecosystem responses coincident with those features. The relationships between micro-topographic setting, snow distribution, inundation, subsurface temperature and thaw depth observed at the NGEE Barrow field sites are now well reproduced in process resolving models such as Pflotran and the Arctic Terrestrial Simulator. Current modeling efforts are investigating how topographically controlled thermal-hydrologic dynamics impact the carbon cycle. The next challenge is to scale these relationships for application in a global climate model grid cell to enable pan-Arctic predictions of future change, including the change in topography and inundation resulting from thawing permafrost and melting ground ice. NGEE-Arctic is funded by the DOE Office of Science, Biological and Environmental Research program.

15118568 Chang, C. (Lawrence Berkeley National Laboratory, Berkeley, CA); McKnight, C. and Kneafsey, T. J. A new approach to quantitatively describe permafrost core using multi-energy CT scanning; composition fraction and morphological analysis [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11A-0541, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Composition discernment, fraction calculation and morphological analysis of a shallow core retrieved from Barrow, AK as part of the Next Generation Ecosystem Experiments in the Arctic (NGEE-Arctic) were conducted to give a quantitative description of the core. Imaging of the core was performed using a medical X-ray computed tomography (CT) scanner, which gives a 3D image with a resolution of 0.195´0.195´0.625mm3. The core consists mainly of mineral, ice, organic matter and air and composition discernment and fraction calculation focus on the first three materials. Four scans with different energies were performed because materials with different density show different responses on scans with varying energies. A calibration curve showing the relationship between density and CT value was built by scanning standard materials having a wide range of density. CT value of the three compositions under four energies was determined by the calibration curve and the core scan. Composition fraction was calculated on the assumption that the core CT value is linearly proportional to the composition fraction and by solving linear least-squares problems with bounds. Comparison of the estimated and measured core CT value shows that the correlation coefficient is more than 0.99, indicating the accuracy of the calculation. Two regions with relatively high fraction of organic matter (10%) were distinguished, which are located at the top of the core and ice filled fractures at the bottom of the active layer. Morphological analysis was applied to the mineral and ice because of low fraction of organic matter. Three segmentations corresponding to ice-rich (with a density of 0.86 to 1.24 g/cm3), transition from ice to mineral (1.24 to 1.47 g/cm3) and mineral-rich (1.47 to 2.65 g/cm3) were applied to the core, and two area (area and area standard deviation) and three morphological (circulatory, roundness and rectangularity) parameters were analysed. By conducting Principle Component Analysis and Cluster Analysis, two principle components were distinguished from the five parameters, giving a quantitative description of the core. The study provides an innovative approach to quantitatively describe the arctic core, which may provide help in understanding geomorphological changes as a result of climate variation in the arctic.

15117570 Bonnaventure, Philip P. (Geological Survey of Canada, Ottawa, ON, Canada); Smith, Sharon L.; Riseborough, Dan W.; Duchesne, Caroline and Ednie, Mark. The ground thermal regime across the Mackenzie Valley Corridor, Northwest Territories Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 29 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115169 Brown, Jerry (Northern Michigan University, Marquette, MI); Nelson, Frederick E.; Romanovsky, Vladimir E.; Seybold, Cathy; Hollister, Robert D. and Tweedie, Craig E. Long-term observations of active layer thawing and freezing, Barrow, Alaska: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, sketch map, 45 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119167 Coulombe, Stephanie (University of Montreal, Department of Geography, Montreal, QC, Canada); Fortier, Daniel; Shur, Yuri; Kanevskiy, Mikhail and Lacelle, Denis. Cryofacies and cryostructures of massive ice found on Bylot Island, Nunavut: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch maps, 54 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119171 Couture, Nicole J. (Geological Survey of Canada, Ottawa, ON, Canada) and Pollard, Wayne H. Ground ice determinations along the Yukon coast using a morphological model: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch maps, 29 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119213 Cray, Heather A. (University of Waterloo, Department of Environment and Resources Studies, Waterloo, ON, Canada); Pollard, Wayne H. and Murphy, Stephen D. Succession in tundra landscapes and its implications for polar restoration efforts; case study of Herschel Island, YT, Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, sketch map, 26 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115154 de Guzman, Earl Marvin (University of Manitoba, Winnipeg, MB, Canada); Piamsalee, Aron; Alfaro, Marolo; Arenson, Lukas U.; Dore, Guy and Hayley, Don. Initial monitoring of instrumented test sections along the Inuvik-Tuktoyaktuk Highway: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, sketch map, 10 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15115171 Duchesne, Caroline (Geological Survey of Canada, Ottawa, ON, Canada); Smith, Sharon L.; Ednie, Mark and Bonnaventure, Philip P. Active layer variability and change in the Mackenzie Valley, Northwest Territories: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 20 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119194 Duguay, Maxime A. (BGC Engineering, Calgary, AB, Canada); Edmunds, Alan; Arenson, Lukas U. and Wainstein, Pablo A. Quantifying the significance of the hydrological contribution of a rock glacier; a review: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, 55 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117551 Fortier, Richard (Université Laval, Centre d'Études Nordiques, Laval, QC, Canada); Guo, Shuai; Lamontagne-Hallé, Pierrick and Yu Wenbing. High-resolution monitoring of thaw subsidence affecting the access road to Umiujaq Airport in Nunavik (Quebec): in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, 8 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117602 Hinkel, Kenneth M. (University of Cincinnati, Cincinnati, OH) and Arp, Christopher. Estimating talik depth beneath lakes in Arctic Alaska: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, 14 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117613 Karnysheva, Elina (Moscow State University, Moscow, Russian Federation); Brouchkov, Anatoli; Cherbunina, Maria; Griva, Gennady; Filippova, Svetlana; Skladnev, Dmitry and Galchenko, Valery. Viruses in ancient ice wedges in the central Yakutia, Siberia: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 45 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119222 Kokelj, S. V. (Northwest Territories Geological Survey, Yellowknife, Canada); Tunnicliffe, J.; Lacelle, D.; Lantz, T. C. and Fraser, R. H. Retrogressive thaw slumps; from slope process to the landscape sensitivity of northwestern Canada: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated, illus. incl. 2 tables, sketch maps, 24 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117549 Lamontagne, Vincent (Université Laval, Département de Génie Civil et Centre d'Etudes Nordiques, Laval, QC, Canada); Périer, Loriane; Lemieux, Chantal; Doré, Guy; Allard, Michel; Roger, Jonathan and Guimond, Anick. Suivi du comportement thermique et mécanique de l'adaptation de la route d'accès à l'aéroport de Salluit au Nunavik, Québec [Monitoring of thermal and mechanical behavior of the adaptation of the airport access road, from Salluit to Nunavik, Quebec]: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (English sum.), illus. incl. 1 table, sketch map, 15 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117605 Marsh, Philip (Wilfrid Laurier University, Waterloo, ON, Canada); de Jong, Tyler; Lesack, Lance; Onclin, Cuyler and Russell, Mark. Lakes of the western Canadian Arctic; past controls and future changes: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 29 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117597 Rick, Brianna (University of Fribourg, Department of Geography, Fribourg, Switzerland); Delaloye, Reynald; Barboux, Chloé and Strozzi, Tazio. Detection and inventorying of slope movements in the Brooks Range, Alaska using DInSAR; a test study: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 3 tables, sketch map, 18 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119178 Rykaart, Maritz (SRK Consulting Canada, Vancouver, BC, Canada); Millar, Megan; Kurylo, John and Wade, Lowell. Evaluating the performance of a frozen core dam founded on ice rich saline marine silts and clays: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 7 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117574 Smith, William E. (University of Calgary, Department of Civil Engineering, Calgary, AB, Canada); Grozic, Jocelyn L. H. and Priest, Jeffrey A. The formation of laboratory analogues of natural hydrate-bearing fine-grained soil: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, 30 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117548 Stirling, Jan L. (Northwest Territories Department of Transportation, Yellowknife, NWT, Canada); Seto, Jack T. C.; Arenson, Lukas U. and Abu Bakar, Muhammad. NWT Highway 3 test sections near Yellowknife: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 12 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15119195 Ward, Melissa K. (McGill University, Department of Geography, Montreal, QC, Canada) and Pollard, Wayne H. Hyper-saline spring dynamics and salt deposits on Axel Heiberg Island, Nunavut: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 2 tables, sketch map, 25 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117606 Woo, Ming-ko (McMaster University, School of Geography and Earth Sciences, Hamilton, ON, Canada) and Thorne, Robin. Summer and winter flows of the Mackenzie River system: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch maps, 18 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117572 Yin Guoan (Chinese Acadmey of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Niu Fujun; Luo Jing; Lin Zhanju; Yang Bingzhuo; Liu Minghao and Li Anyuan. Deviations in gridded field measurements of ground temperature and active layer thickness in Wudaoliang Basin, Qinghai-Tibet Plateau: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 30 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15117557 Zhang, Guangwen (Tetra Tech EBA, Edmonton, AB, Canada) and Hoeve, Ed. Geotechnical design of thermopile foundation for a building in Inuvik: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 7 tables, 14 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

15120716 Iwahana, Go (University of Alaska at Fairbanks, Fairbanks, AK); Uchida, Masao; Kondo, Miyuki; Yoshikawa, Kenji and Hinzman, Larry. Development of a palsa along the Denali Highway, Alaska [abstr.]: in Japan Geoscience Union meeting 2014, Abstract - Japan Geoscience Union Meeting, 2014, 2014. Meeting: Japan Geoscience Union meeting 2014, April 28-May 2, 2014, Yokohama, Japan. Accessed on Jan. 15, 2015.

Palsa is a peaty permafrost mound distributing in continuous and discontinuous permafrost zones. Main mechanism of the development the mounds is frost heave by ice segregation of peat or mineral soil material. Upper part of palsa usually consists of peat and lower part of a core of alternating layer of segregated ice and mineral soil material. History of paleo-environment around the period of last glacial retrieve in surrounding area can be inferred from analysis of palsa cores and stratigraphy. Our target palsa was located along the Denali Highway, Alaska, and the mound was truncated during highway construction in 1957. The outcrop of palsa have been eroded away from the highway line about 20 m partly exposing the internal structure. This permafrost mound was firstly introduced as palsa by Pewe in 1983, and from dating of basal peat, deglaciation of this area occurred at least about 10500 year BP. History of palsa development and environment change was reconstructed from results of analysis from 6.5 m core and ground temperature.

URL: http://www2.jpgu.org/meeting/2014/PDF2014/2014ALL_e.pdf

15112602 Konen, Michael (Northern Illinois University, Department of Geography, DeKalb, IL). Impact of relict ice-wedge polygons on modern soil spatial distribution [abstr.]: in Geological Society of America, North-Central Section, 49th annual meeting, Abstracts with Programs - Geological Society of America, 47(5), p. 89, May 2015. Meeting: Geological Society of America, North-Central Section, 49th annual meeting, May 19-20, 2015, Madison, WI.

The occurrence and distribution of relict permafrost features is poorly understood and documented in the mid-continent, especially in glaciated landscapes. The impact of these processes on modern soil distribution is even more poorly understood. This presentation will focus on the occurrence of relict ice-wedge polygons and their impact on modern soil distribution in the mid-continent. Field evidence will focus on the spatial distribution of modern soils in Ohio, Illinois, Wisconsin, and Iowa. Emphasis will be placed on the distribution and occurrence of sodium affected soils in south central Illinois and their relationships to relict ice-wedge polygons.

15112597 Rovey, Charles W., II (Missouri State University, Department of Geography, Geology, and Planning, Springfield, MO); Balco, Greg and Siemens, Mike. Geochronologic constraints on the age and depositional mechanisms of the Grover Gravel in western St. Louis County, Missouri [abstr.]: in Geological Society of America, North-Central Section, 49th annual meeting, Abstracts with Programs - Geological Society of America, 47(5), p. 88, May 2015. Meeting: Geological Society of America, North-Central Section, 49th annual meeting, May 19-20, 2015, Madison, WI.

The Grover Gravel in St. Louis County, Missouri often has been correlated with the "Lafayette-type" gravels, which mantle upland surfaces along the margins of the Mississippi Embayment several hundred kilometers to the south. Here we report new data for these deposits from tephrostratigraphy and cosmogenic-nuclide burial dating. Cosmogenic-nuclide burial dates for the southern "Lafayette" gravels indicate a late Pliocene age, in agreement with evidence that they predate continental glaciation. Type-Grover deposits in western St. Louis County, however, postdate initial formation of the Laurentide Ice Sheet. First, the Grover contains large erratic boulders, which must have been transported at some point by glacial ice. Secondly, the Grover locally overlies a pediment surface that truncates a highly weathered remnant of the (2.4 Ma) Atlanta till. Finally, the base of the Grover fills ice-wedge casts within substrate materials, demonstrating that it was deposited under permafrost conditions during a continental glaciation. The stratigraphic constraints are consistent with a single limiting burial date at the type section, which provides a maximum age of 0.85 +/- 0.4 Ma for the Grover. This age, combined with a normal remanent magnetization within a conspicuous white silt layer near the base, indicates that the type-Grover is probably early Middle Pleistocene (< 0.78 Ma) in age. The white silt is a weathered volcanic ash. Pumice shards within the ash far outnumber platy or bubble-wall shards, and biotite is abundant within the silt's heavy-mineral fraction. This composition is inconsistent with ash from Yellowstone eruptions, but closely matches that of the Bishop ash (0.77 Ma). This age also coincides with burial ages for the oldest normal-polarity till in Missouri. Other features indicate that the Grover is not a typical fluvial deposit. The Grover is present widely atop numerous upland remnants, but there is no evidence that deposition was restricted to discrete valleys or channels. Moreover, clasts are usually matrix supported, indicating deposition from mass flows, not traction currents. Thus, we posit that the Grover Gravel in the type area was deposited during a time of widespread landscape instability, which was triggered by a unique combination of melting permafrost mantled by volcanic ash.

15112093 Anderson, L. (U. S. Geological Survey, Geosciences and Environmental Change, Denver, CO); Birks, S. Jean; Rover, J. and Guldager, Nikki. Recent and late Holocene Alaskan lake changes identified from water isotopes [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract PP31D-1172, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

To identify the existence and cause of recent lake area changes in the Yukon Flats, a region of discontinuous permafrost in north central Alaska, we evaluate lake water isotope compositions with remotely sensed imagery and hydroclimatic parameters. Estimates of the ratio of water lost by evaporation to that gained by inflow (E/I) were derived from an isotope-based water balance model. The isotope labels are also used to identify the dominant sources for lakes such as rainfall and snowfall, groundwater, rivers, or thawed permafrost. These parameters are then used in conjunction with climatic data and remotely sensed imagery to identify the patterns and causes of recent lake area changes and for evaluation with lake sediment oxygen isotope records of late Holocene lake water isotope variations. Lake water isotope samples from 83 lakes were acquired in July, August or September between 2007 and 2010 by fixed wing aircraft. An additional set of smaller lakes (n = 33) was sampled by helicopter in September 2009. In July 2011 59 lakes were sampled on foot within five distinct 11.2-km2 areas. River water data used here are previously collected during the months of June through October between 2006 and 2008. Isotope compositions indicate that mixtures of precipitation, river water, and groundwater source ~95% of the studied lakes. The remaining minority are more dominantly sourced by snowmelt and/or permafrost thaw. Isotope-based water balance estimates indicate 58% of lakes lose more than half of inflow by evaporation. For 26% of the lakes studied, evaporative losses exceeded supply. Surface area trend analysis indicates that most lakes were near their maximum extent in the early 1980s during a relatively cool and wet period. Subsequent reductions can be explained by moisture deficits and greater evaporation. Comparison with late Holocene isotope values and trends indicates recent changes are within the range of late Holocene variability. The records indicate a drier and warmer than present climate prior to 4000 years ago, whereas it was wetter and cooler between 4000 and 2000 years ago. These findings indicate that attempts to project future high-latitude lake change will benefit from considering the effects of decade to multi-decadal scale hydroclimatic variations.

15118721 Bauch, H. A. (GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany); Abramova, E.; Alenius, T. and Saarnisto, M. Late Holocene peat growth at the northern Siberian periphery and its relation to Arctic climate change [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract PP21B-1330, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

During the last postglacial evolution of the shallow northern Siberian shelf systems regional sea level in the Arctic came to its Holocene highstand some time between 5 to 6 ka. After that time a general stabilization of the sedimentary regime occurred. That is well noted in a drastic decrease in sedimentation rates observed in all sediment cores taken from middle to outer shelf water depths of the Laptev Sea. But, at water depths lower than 30 meters, i.e., in the inner shelf and nearer to the coasts, sedimentation continued at relatively higher rates, presumably due to input of terrigenous material from river runoff as well as coastal erosion. Compared with that latter process, the huge Lena Delta should comprise a region of sediment catchment where aggradation wins over erosion. However, little is known about the detailed history of this delta during the second half of the Holocene. In order to gain more insight into this issue we have investigated three islands within the Lena Delta. All of these are comprised of massive peat of several meters in thickness. Picking discrete specimens of water mosses (Sphagnum) only, we have radiocarbon-dated these peat sections. The depth/age relation of the sampled profiles reflect the growth rate of peat. It shows that the islands' history above the present-day delta-sea level is about 4000 yrs. old. Moreover, a significant change in peat growth occurred after 2500 yrs BP in both, accumulation and composition, and allows the conclusion of a major shift in Arctic environmental conditions since then. Thus, our results may add further information also for other coastal studies, as the ongoing degradation of the rather vulnerable permafrost coast in the Laptev Sea and elsewhere along the North Siberian margin is often mentioned in context with recent Arctic climate change due to global warming.

15118603 Bowden, W. B. (University of Vermont, Burlington, VT); Gooseff, M. N.; Stuckey, J. J.; Fulweber, R. A. and Larouche, J. R. Rapid recovery of a gully thermokarst; 10 years of observation of the Toolik River thermokarst, North Slope, Alaska [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC13C-0659, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

As permafrost thaws, previously frozen soils may become unstable and subside, in some cases forming thermo-erosional features such as gully thermokarst (GTKs). The formation of these features can result in sediment and nutrient inputs to local streams and lakes. The initial evolution of GTKs is rapid (months to several years) and appears to follow a progression in which the loss of ground ice in the soil creates a subsurface cavity that allows for the transport of water downslope, followed by the collapse of the overlying soil into the cavity, with a subsequent period of sediment and nutrient export. However, there is considerable uncertainty about the length of time these features remain unstable and actively transport sediments and nutrients. We followed the evolution of one moderately-sized (~5,000 m2) GTK located in the headwaters of the Toolik River (N68.692733° W149.205433°) on the North Slope of Alaska (USA). This feature formed in July 2003 and we monitored it for several years thereafter. In 2007 we began to monitor the shape and contours of this feature and quantified the level of ecologically important solutes it exports to the local stream. As expected, large quantities of sediment and nutrients were exported from this feature when it first formed. However, within a year or two the sediment export decreased to episodic events and the nutrient export, while elevated above reference levels, was not remarkably high. Between 2007 and the present (2014), the shape and topography of the feature have changed very little (Figure) except for some headwall retrogression, suggesting that long-term sediment transport has decreased dramatically. Thus, the overall sediment loading to the river was smaller and has decreased more rapidly than we expected. The rapid reduction in sediment and nutrient delivery is consistent with the more recent geomorphic evolution and stabilization of this feature. We conclude - contrary to our initial hypotheses - that these features form and stabilize rather quickly (~10 years) and that their influences on local streams and lakes might be ephemeral. Thus, the greater importance of these features may be as indicators of general permafrost degradation in the area and the attendant losses of carbon and other nutrients that this degradation implies.

15118556 Chen, A. C. (Stanford University, Geophysics, Stanford, CA); Liu, L.; Schaefer, K. M.; Parsekian, A.; Jafarov, E. E.; Zebker, H. A. and Zhang, T. Remotely sensed active layer thickness (ReSALT) from InSAR data near Toolik Lake in northern Alaska [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract G53A-03, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Toolik Field Station is built on spatially continuous permafrost on the north slope of Alaska. Seasonal surface subsidence and uplift occurs in permafrost regions due to thaw settlement and frost heave as the active layer thaws and refreezes. Using L-band (23.6 cm wavelength) InSAR data from ALOS-PALSAR acquired between 2006 and 2010, we use a small-baseline subset (SBAS) method to estimate seasonal surface subsidence and retrieve fine-resolution maps of active layer thickness (ALT) for a ~25´25 km area surrounding Toolik Field Station (located at 68.63°N, -149.60°E). We compare these remotely sensed ALT (ReSALT) results with in situ data from: 1) the Circumpolar Active Layer Monitoring (CALM) network showing mean ALT of ~40-50 cm in the region surrounding Toolik Field Station, corresponding to seasonal subsidence of 1 to 2 cm, and 2) mechanical probing measurements of ALT, obtained during field work in the study area in August 2014. We also solve for secular subsidence trends from the InSAR data. The trends are close to zero in most places, but larger subsidence trends in some isolated areas could be due to thermokarst processes (long-term thawing of ice-rich permafrost). We note, however, that downslope motion due to gelifluction cannot be separated from vertical thermokarst-related deformation without incorporating InSAR measurements from multiple look angles. Two key limitations to our method are the spatial variability of volumetric soil moisture content and the accuracy of the DEM needed to correct for topographic effects. We investigate the use of bulk volumetric water content inferred from ground-penetrating radar (GPR) data to improve the ReSALT retrieval algorithm. We also quantify the effect of DEM accuracy on ReSALT uncertainties, leads to requirements for DEM accuracy in InSAR-based ALT retrieval.

15112077 Curry, B. Brandon (University of Illinois at Urbana-Champaign, Prairie Research Institute, Illinois State Geological Survey, Champaign, IL). Multiple nonconformities in ice-walled lake successions indicate periods with cold summers (24.4-22.5 ka, 21.1-19.2 ka, 18.5-18.1 ka) during the Last Deglaciation in Northeastern Illinois, USA [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract PP31C-1156, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Unprecedented age control on many last glacial stratigraphic units and morainal ice-margin positions are interpreted from AMS radiocarbon ages of tundra plant macrofossils archived in low-relief ice-walled lake plain (IWLP) deposits the Lake Michigan Lobe (south-central Laurentide Ice Sheet). IWLPs are periglacial features that formed on morainal dead-ice permafrost. Lacustrine sediment, and the fossils contained therein, had physical and temporal proximity to the glacier which formed the underlying moraine. In modern ice-walled lakes, as the lake's ice cover begins to melt, moats form which allows access of sloughing tundra-mantled active layer sediment (soil) into the lakes. Multiple AMS ages from two sites with proglacial sediment buried by glacial max LIS diamicton, and IWLPs reveal evidence of episodic plant growth and sedimentation including ca. 24.0 to 24.4 ka (post Shelby Phase), 22.5 to 21.1 ka (post Livingston Phase), 18.1 to 17.4 ka (post Woodstock Phase). although presently based on negative evidence, the associated nonconformities (listed in title) indicate periods when cold conditions did not promote development of the estival moat. Although the evidence does not preclude tundra growth during the cold summers, there was little landscape modification due to limited thawing of the active layer. At approximately the onset of the 19.2-18.5 "warm" period, at least two large deglacial discharge events flooded the Fox and Kankakee tributary valleys of the Illinois River. The latter, known as the Kankakee Torrent, occurred at 19.05-18.85 ka (s1 range) at the Oswego channel complex. The temporal coincidence of the torrents and sedimentation in ice-walled lakes suggests that the post-Livingston Phase nonconformity (21.1-19.2 ka) was a period of lessened meltwater discharge through subglacial conduits (tunnel valleys) as the frozen toe promoted formation of subglacial lakes, buildup of pore-water pressures, and the release of subglacial water as "torrents". In the case of the Fox and Kankakee torrents, ice-marginal discharge first flowed into proglacial lakes which ultimately breached moraines, resulting in catastrophic "torrents". Hence, present knowledge does not allow determination of the nature of the subglacial release (catastrophic vs. large, steady discharge).

15111999 Davydov, S. P. (Russian Academy of Sciences, Far East Branch, Institute of Geography, NorthEast Science Station, Cherkil, Russian Federation); Davydova, A.; Makarevich, R.; Loranty, M. M. and Boeskorov, G. High-latitude steppe vegetation and the mineral nutrition of Pleistocene herbivores [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC31B-0467, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

High-latitude steppes were widespread and zonal in the Late Pleistocene and formed a landscape basis for the Mammoth Biome. Now the patches of these steppes survived on steep slopes under southern aspects. These steppes serve as unique information sources about the Late Pleistocene "Mammoth" steppe. Numerous data obtained by palynological, carpological, and DNA analysis of plant remains from feces and stomach contents of Pleistocene herbivore mummies, as well as from buried soils and enclosing deposits show that they are similar to modern steppe plant assemblage in taxa composition. Plant's nutrient concentrations are of fundamental importance across Pleistocene grass-rich ecosystems because of their role in the support of large herbivores. The average weight of an adult mammoth skeleton (about 0.5 tons) and of a woolly rhinoceros (about 0.2 tons) clearly suggests this. Detailed studies on fossil bone remains showed mineral deficiency in large Pleistocene herbivores. A three-year study of ash and mineral contents of two types of relict steppe vegetation at the Kolyma Lowland, Arctic Siberia has been carried out. Nowadays refugia of similar vegetation are located not far (1-15 km) from the Yedoma permafrost outcrops were abundant fossil remains are found. Dominant species of the steppe vegetation were sampled. Preliminary studies indicate that the ash-content varied 1.5-2 times in species of steppe herbs. The Ca, P, Mg, K element contents was higher for most steppe species than in the local herbaceous vegetation, especially in Ca and P. One of the most important elements of the mineral nutrition, the phosphorus, was always found in higher concentrations in the steppe vegetation than in plants of recently dominant landscapes of the study area. It should be noted that the mineral nutrient content of the modern steppe vegetation of Siberian Arctic is comparable to that of the recent zonal steppe of Transbaikal Region. This study supports the hypothesis that aboveground mineral concentrations of late Pleistocene grass-rich ecosystem were consistently higher than that of the recent common species of Siberian Arctic grassland. The source of mineral nutrients in the Pleistocene high-latitude steppe vegetation served as one of the reasons for the existence and survival of large herbivores in the Mammoth Biome.

15112055 Hartmann, Kai (Free University of Berlin, Berlin, Germany); Diekmann, Bernhard; Lehmkuhl, F.; Reicherter, K. R.; Stauch, G. and Wuennemann, B. Reconstruction of late Quaternary environmental changes in large endorheic basins; challenges and problems [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC43C-0761, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

In paleoclimate and geodynamic studies large endorheic drainage basins generally provide long-term archives of hydro-climatological and tectonic changes including a transient topography. Sediment cascades from sources to sinks are playing a scale-depending role in the reconstruction of process dynamics by using sedimentary records. We present a holistic study on the Hei He drainage basin at the northern margin of the Tibetan Plateau by combining multi-disciplinary and multi-site approaches. The drainage system is crossing margins of extreme climatic conditions from the glaciated and permafrost sources within the >5000 m high Qilian Shan to the hyper-arid Ejina Basin as endorheic sink with a catchment size of ca. 180,000 km2 and a endorheic basin area of approx. 28,000 km2. Two 230 m long drill-cores at the depocenter of Ejina basin recover a sedimentation history of about 250,000 years and integrate at least two glacial-interglacial cycles of climate change and a considerable geodynamic within the second largest strike-slip system in the world. Sedimentation rate/subsidence estimations with consideration of climate-induced hydrological changes affecting the wider study and sink area provided data on the mountain uplift/basin development and the effects of tectonically induced changes of the drainage system. Based on 15 paleohydrological records covering the last ca. 35,000 years corroborated by >75 14C AMS data, we can demonstrate that water divides have been spatially variable with temporal opening of the endorheic system. Thus, small-scale changes in topography are able to explain extreme changes of sedimentation rates within long-term records in the depocenter. The major fault systems in the drainage centers intensely modified the drainage system and catchment size resulting in extreme hydrological changes in the basin as recorded in the long-cores. A brief view into the Okavango system in Botswana indicates that the complexity of interrelated non-climatic processes of huge drainage basins crossing large fault systems and climate zones is not unique.

15118574 Herndon, E. (Kent State University, Kent, OH); Roy Chowdhury, T.; Mann, B.; Graham, D. E.; Wullschleger, S. D.; Gu, B. and Liang, L. Geochemical drivers of organic matter decomposition in the active layer of Arctic tundra [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11B-0554, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Arctic tundra soils store large quantities of organic carbon that are susceptible to decomposition and release to the atmosphere as CO2 and CH4. Decomposition rates are limited by cold temperatures and widespread anoxia; however, ongoing changes in soil temperature, thaw depth, and water saturation are expected to influence rates and pathways of organic matter decomposition. In order to predict greenhouse gas releases from high-latitude ecosystems, it is necessary to identify how geochemical factors (e.g. terminal electron acceptors, carbon substrates) influence CO2 and CH4 production in tundra soils. This study evaluates spatial patterns of aqueous geochemistry in the active layer of low- to high-centered polygons located at the Barrow Environmental Observatory in northern Alaska. Pore waters from saturated soils were low in sulfate and nitrate but contained abundant Fe which may serve a major terminal electron acceptor for anaerobic microbial metabolism. Relatively high concentrations of soluble Fe accumulated in the middle of the active layer near the boundary between the organic and mineral horizon, and we infer that Fe-oxide reduction and dissolution in the mineral horizon produced soluble Fe that diffused upwards and was stabilized by complexation with dissolved organic matter. Fe concentrations in the bulk soil were higher in organic than mineral horizons due to the presence of these organic-Fe complexes and Fe-oxide precipitates. Dissolved CH4 increased with increasing proportions of dissolved Fe(III) in saturated soils from transitional and low-centered polygons. The opposite trend was observed in drier soils from flat- and high-centered polygons where deeper oxidation fronts may inhibit methanogenesis. Using multiple spectroscopic and molecular methods (e.g. UV-Vis, Fourier transform infrared, ultrahigh resolution mass spectrometry), we also observed that pore waters from the middle of the active layer contained more aromatic organics than in mineral soils near the permafrost boundary, where pore waters were depleted but soils were enriched with aromatic organic moieties. The geochemical depth gradients we document for tundra soils influence organic matter degradation and are pertinent for understanding C dynamics as thaw depth and duration increase in high-latitude soils.

15118579 Kim, Y. (University of Alaska, Fairbanks, Fairbanks, AK). Effect of thaw depth on fluxes of CO₂ and CH₄ in manipulated Arctic coastal tundra of Barrow, Alaska [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11B-0561, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Changes in CO2 and CH4 emissions represent one of the most significant consequences of drastic climate change in the Arctic, by way of thawing permafrost, a deepened active layer, and decline of thermokarst lakes in the Arctic. This study conducted flux-measurements of CO2 and CH4, as well as environmental factors such as temperature, moisture, and thaw depth, as part of a water table manipulation experiment in the Arctic coastal plain tundra of Barrow, Alaska during autumn. The manipulation treatment consisted of draining, controlling, and flooding treated sections by adjusting standing water. Inundation increased CH4 emission by a factor of 4.3 compared to non-flooded sections. This may be due to the decomposition of organic matter under a limited oxygen environment by saturated standing water. On the other hand, CO2 emission in the dry section was 3.9-fold higher than in others. CH4 emission tends to increase with deeper thaw depth, which strongly depends on the water table; however, CO2 emission is not related to thaw depth. Quotients of global warming potential (GWPCO2) (dry/control) and GWPCH4 (wet/control) increased by 464 and 148 %, respectively, and GWPCH4 (dry/control) declined by 66 %. This suggests that CO2 emission in a drained section is enhanced by soil and ecosystem respiration, and CH4 emission in a flooded area is likely stimulated under an anoxic environment by inundated standing water. The findings of this manipulation experiment during the autumn period demonstrate the different production processes of CO2 and CH4, as well as different global warming potentials, coupled with change in thaw depth. Thus the outcomes imply that the expansion of tundra lakes leads the enhancement of CH4 release, and the disappearance of the lakes causes the stimulated CO2 production in response to the Arctic climate change.

15112107 Klein, E. S. (University of Alaska-Anchorage, Anchorage, AK); Cherry, J. E.; Young, J. M.; Noone, D. C.; Leffler, A. J. and Welker, J. M. Arctic cyclone water vapor isotope ratios support past sea ice retreat recorded in Greenland ice sheet [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract PP31D-1186, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Rapid warming in the Arctic is associated with important changes to the Arctic water cycle: loss of sea ice, increasing atmospheric humidity, permafrost thaw, and water-induced ecosystem changes. Understanding these complex modern processes is critical to interpreting past hydrologic changes preserved in paleoclimate records and assessing future Arctic changes. Cyclones are a prevalent feature of the Arctic and water vapor isotope ratios during these events provide insights into modern hydrologic processes that help explain past changes to the Arctic water cycle. Here we present continuous measurements of water vapor isotope ratios (d18O, d2H, d-excess) in northern Alaska from a 2013 Arctic cyclone event. This cyclone resulted in a sharp d-excess decrease and disproportional d18O enrichment, indicative of an open Arctic Ocean water vapor source with higher humidity. Past transitions to warmer climates inferred from Greenland ice core records also reveal sharp decreases in d-excess values, hypothesized to represent reduced sea ice extent and an increase in oceanic moisture source to Greenland Ice Sheet precipitation. Thus, measurements of water vapor isotope ratios during an Arctic cyclone provide a critical processed-based explanation, and the first direct confirmation, of relationships previously assumed to govern water isotope ratios during sea ice retreat and increased input of northern ocean moisture into the Arctic water cycle.

15118580 Long, H. E. (University of Glasgow, Glasgow, United Kingdom); Waldron, S.; Hoey, T.; Garnett, M. and Newton, J. Quantifying the magnitude, spatiotemporal variation and age of aquatic CO₂ fluxes in Western Greenland [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11B-0562, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

High latitude regions are experiencing accelerated atmospheric warming, and understanding the terrestrial response to this is of crucial importance as: a) there is a large store of carbon (C) in permafrost soils which may be released and feedback to climate change; and, b) ice sheet melt in this region is accelerating, and whilst this will cause albedo and heat flux changes, the role of this in atmospheric gas release is poorly known. To understand how sensitive arctic environments may respond to future warming, we need measurements that document current C flux rates and help to understand C cycling pathways. Although it has been widely hypothesised that arctic regions may become increasingly significant C sources, the contribution of aquatic C fluxes which integrate catchment-wide sources has been little studied. Using a floating chamber method we directly measured CO2 fluxes from spatially distributed freshwaters (ice sheet melt, permafrost melt, and lakes/ponds) in the Kangerlussuaq region of western Greenland during the early part of the summer 2014 melt season. Fluxes from freshwaters with permafrost sources were in the range -3.15 to +1.28 mmol CO2 m-2 s-1. Fluxes from a river draining the ice sheet and the Russell Glacier were between -2.19 and +4.31 mmol CO2 m-2 s-1. These ranges show the systems can be both sources (efflux) and sinks (influx) of CO2. Most freshwater data worldwide shows CO2 efflux and so recording aquatic systems being a CO2- -sink is unusual. Our data show spatial and temporal variations that are related to hydraulic as well as biogeochemical processes. Additionally, where we recorded CO2 efflux we collected effluxed CO2 for radiocarbon analysis. The measured age of the released gas will help to identify the sources and dominant transport processes of CO-2 (e.g. entrained modern atmospheric CO2, or old CO2 trapped during ice formation released through ice melt, or CO2 derived from respiration of soil and sediment organic matter). These samples are currently being analysed and we intend to present this original data at AGU. By directly measuring aquatic CO2 efflux and age from this climatically sensitive arctic location and quantifying drawdown in high-pH ice melt streams, we have a unique dataset that aids understanding of key feedbacks affecting the impact of projected future climate change.

15118567 Mayedo, A. L. (University of Florida, Ft Walton Beach, FL); Remiszewski, K.; Prado, M. F.; McCalley, C. K.; Bryce, J. G. and Varner, R. K. Mercury content of vegetation across a sub-Arctic mire thaw gradient [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11A-0536, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Mercury deposition from natural and anthropogenic sources is known to accumulate in subarctic environments, particularly peatlands, due to their abundant organic matter that effectively sequester mercury and other heavy metals. Given direct links between mercury mobilization and aquatic and terrestrial ecosystem health, it is vital to understand the degree to which thawing peatlands serve as sinks or sources of mercury to the environment. In a peat mire underlain by permafrost in subarctic Sweden (Stordalen Mire, lat. 68°21' N, lon. 19°03' E), the onset of climate-driven permafrost thaw influences regional hydrology and therefore the composition of plant communities. The purpose of this work is to assess mercury content of vegetation and underlying peat across a thaw gradient. The study was conducted on two transects that transition from an unthawed dwarf shrub-dominated hummock community to a fully thawed graminoid-dominated wet depression community. Drained hummock sites at initial stages of the thaw sequence are characterized by a diverse graminoid and shrub community, including Eriophorum, Andromeda, and Empetrum populations underlain by Sphagnum litter. Semi-wet sites are characterized by moist Sphagnum mats with sparse populations of Eriophorum and Empetrum. Wet sites are characterized by tall graminoid Eriophorum underlain by submerged Sphagnum mats. Total mercury abundances in vegetation was analyzed via thermal decomposition. Generally, mercury contents in plant tissues exhibit decreasing concentrations of mercury with increasing thaw. Higher concentration of mercury in vegetation in drained sites versus that in wet sites supports the notion that mercury in the dry mire is exported into the local water and peat column. Changing mercury concentration profiles in peat core afford a means to assess that mercury is mobilized during the thaw but not fully exported from the thawed wetlands. Our results, coupled with earlier findings of mobilization and subsequent partial retention of mercury in peat along other thaw sequences, suggest complex pathways for mercury reallocation during the thawing process.

15112044 Meng Fanchong (Chinese Academy of Sciences, Institute of Tibetan Plateau Research, Beijing, China) and Su, F. Terrestrial water storage changes in the Tibetan Plateau in the past decade and the possible cause [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC43C-0733, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Terrestrial water storage (TWS) is the water stored on and below the land surface, which includes snow, ice, soil moisture, groundwater, and surface water. TWS is a fundamental component of the terrestrial hydrological cycle given that precipitation (P) reaching the land surface is balanced by evapotranspiration (ET), runoff (R), and the change of terrestrial water storage (TWSC) [P=R+ET+TWSC]. As an integrated measure of surface and groundwater availability, TWS has significant implications for water resources management. The Tibetan Plateau and its surrounding areas (TP), which are characterized by high elevation, extensive glaciers, permafrost, snowpack, and mountain lakes, is known as the "roof of the world", the Third Pole, and also the water towers of Asia. Studies of meteorological observations, reanalysis data, and ice core records have suggested a warming trend over the TP in recent decades. Along with the rising temperature, the detected glacier melt, permafrost degradation, and lakes changes in the TP will thus affect the water storage changes and the hydrological cycle in the area. In this study, we examine the spatial-temporal variation of TWS change over the TP through the Gravity Recovery and Climate Experiment (GRACE) satellite data and the VIC land surface hydrologic model during 2004-2013. Meanwhile, the spatial-temporal characteristics of precipitation, evapotranspiration, and snow cover as well as the distribution of glaciers, lakes, and frozen soil are analyzed to examine the factors that might be responsible for the TWS changes in the TP. The objective of our study is to achieve a better understanding of the water balance change in the TP under the warming climate. Our work could provide a basis for conservation strategies and policy decisions for the fragile, invaluable eco-hydrological environment in the Tibet Plateau.

15118728 Nichols, J. E. (Lamont-Doherty Earth Observatory, Palisades, NY) and Peteet, D. M. Holocene changes in climate and ecological gradients across the Alaskan Arctic assessed with multiple organic geochemical and paleoecological techniques [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract PP21B-1337, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

There is a strong climate gradient across the Alaskan Arctic, with important implications for ecology, carbon and nutrient cycling, terrestrial hydrology and permafrost. Hydrogen isotopes of precipitation are important tool for measuring this climate gradient, as it summarizes variability in precipitation, temperature, and other parameters of the ocean-atmosphere system-all important for understanding the rapidly changing climate of the Arctic. We reconstructed D/H ratios of precipitation along with other hydrological and ecological parameters in a series of peatlands throughout the Alaskan Arctic. We reconstruct climate parameters using the hydrogen isotope ratios of leaf wax n-alkanes and paleoecology using distributions of lipid biomarkers and macrofossil identification. By reconstructing D/H ratios at all sites, we are able to compare disparate environments to robustly establish changing precipitation isotope gradients over the Holocene and in the Late Glacial. We investigated four sites in a southeast-northwest transect of the Alaskan Arctic, each with stratigraphies covering the Holocene, and two extending into the Late Glacial. We used data from this transect to identify temporal changes in the gradient of precipitation D/H ratios. We also assessed the impact of these changes in the context of Arctic peatland and permafrost carbon accumulation, as these impacts are key to our understanding of the interactions and feedbacks of the terrestrial carbon cycle on recent and future Arctic warming.

15118631 Northington, R. (University of Maine, Orono, ME); Osburn, C. L.; Anderson, N. J. and Saros, J. E. Patterns and changes in dissolved organic carbon (DOC) across lakes in southwestern Greenland [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC14A-01, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Rapid warming of the Arctic over the last few decades has led to changes in biogeochemical cycling of both aquatic and terrestrial ecosystems in the region. Decreases in permafrost and changes in hydrological connectivity have changed the movement of ions and nutrients across the landscape. The combined effects of increased temperature and altered terrestrial inputs can lead to changes in lake productivity as well. Although all of the Arctic is warming, Greenland has demonstrated the greatest average rate of temperature increase over the past few decades relative to other areas. Therefore, we assessed dissolved organic carbon (DOC) within 26 lakes in southwestern Greenland from the ice sheet towards the coast during the summers of 2013 and 2014. In these lakes, DOC concentrations ranged from 4-40 ppm and were fairly consistent across the Arctic growing season. However, these results indicate widespread changes in DOC over the last decade, ranging from no change to a 60% reduction of in-lake concentrations. We hypothesize that rapid climate change in the region has led to these changes in carbon availability and processing across the landscape and within lake basins. While the exact mechanisms are still being explored, such changes within a short time scale can have implications for carbon cycling in the Arctic and globally in the near future.

15118722 Opel, T. (Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Potsdam, Department of Periglacial Research, Potsdam, Germany); Meyer, H.; Fritzsche, D.; Laepple, T. and Alexander, D. Late Holocene Russian Arctic climate variability; spatial and seasonal aspects inferred from glacier and ground ice [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract PP21B-1331, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

The Arctic currently experiences an unprecedented warming. This dynamic response to changes in climate forcing as well as corresponding feedbacks as sea ice retreat make the Arctic a key region to study past and future climate changes. Recent Arctic-wide temperature reconstructions indicate a long-term cooling prior to the ongoing warming. However, they are based mostly on proxies that record summer information and hence are assumed to be seasonally biased towards the summer. Moreover, the Russian Arctic is significantly underrepresented in these Arctic-wide reconstructions. Here we present glacier and ground ice records from Northern Siberia that provide valuable information for a better spatial and seasonal understanding of Holocene climate variability in the Arctic. The high-resolution Akademii Nauk d18O ice core record (Severnaya Zemlya) proves the late Holocene cooling and the pronounced warming after 1800. It shows neither a prominent Medieval Climate Anomaly nor a Little Ice Age but gives evidence of several abrupt warming and cooling events during the last centuries, also found in ice-core records from Svalbard and Franz Josef Land. They may be related to the regional internal climate variability, i.e. atmosphere-sea ice feedbacks in the Barents and Kara Seas region. Ice wedges were studied at several study sites in the Lena River delta and the coastal permafrost lowlands of the Laptev Sea region. They are formed by the repeated filling of wintertime thermal contraction cracks by snow melt water in spring. Radiocarbon dating of organic matter enables the generation of centennial scale d18O records that are indicative of temperatures in the cold period of the year (winter and spring). Our ice wedge records show general increasing d18O trends over the mid and late Holocene and an unprecedented recent warming. Both may be related to the changes in orbital forcing during the cold season as well as in greenhouse gas concentrations over the last millennia. However, this pattern is in contradiction to most other Arctic temperature records that, in turn, are likely summer-biased. Our ice-wedge records add therefore unique and substantial climate information for understanding the seasonal patterns of Holocene climate in the Arctic and might help to bridging the gap between proxy records and climate models in the Arctic.

15118577 Pirk, N. (Lund University, Physical Geography and Ecosystem Science, Lund, Sweden); Parmentier, F. J. W.; Mastepanov, M.; Christiansen, H. H. and Christensen, T. R. High Arctic tundra greenhouse gas fluxes; new insights from Adventdalen, Svalbard [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11B-0559, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Data on greenhouse gas (GHG) exchange in high Arctic environments is rare but badly needed, as the environment in these places will likely respond early and most rapidly to climate warming. Also, the high Arctic holds carbon stocks in permafrost that is most likely to be made vulnerable to decomposition as ecosystems get warmer. In 2011 we established a long-term GHG flux-monitoring site in the Adventdalen valley on the Svalbard archipelago. The site is characterised by little precipitation (about 200 mm/year), a strong marine influence (summer air temperatures predominantly around 5 degrees Celsius), and a continuous permafrost ground with low-centered ice wedge polygons at the surface. The measurement equipment features an eddy-covariance tower and an automatic chamber system, both set up in accordance with already existing monitoring programs (INTERACT, ICOS and the Greenland Ecosystem Monitoring program). Here, we present the first results of this multi-year campaign, such as the pattern of carbon dioxide and methane fluxes during the growing and shoulder seasons, including the recently discovered autumn burst, as well as carbon dioxide fluxes during wintertime. Carbon dioxide fluxes measured with eddy-covariance agree well with the automatic chamber data, and indicate that the site acts as a sink for carbon dioxide. Methane fluxes measured by the automatic chamber system indicate a significant methane source, which is, however, weaker than at comparable sites in Greenland. There is a high degree of inter-annual variation in methane emissions, which seems to be driven by the amount of precipitation in summer. On top of that, there is a strong spatial variability resembling the polygonal ground pattern. This variability is also reflected in the occurrence of the methane autumn burst, which could be detected and is spatially and temporally distributed at a few locations and years.

15117095 Schneider, Philipp (University of Zurich, Zurich, Switzerland) and Lange, Andreas. Alpine groundwater; pristine aquifers under threat? [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H21D-0766, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Glacier and permafrost retreat are prominent climate change indicators. However, the characteristics of climate and hydrology in mountain areas remain poorly understood relative to lowland areas. Specifically, not much is known about alpine groundwater, its recharge and water quality variations, as these remote reservoirs are rarely monitored. As global temperatures rise, glaciers and permafrost will continue to retreat forming new sediment deposits and changing infiltration conditions in high alpine terrain. Climate change impacts the hydro-chemical composition of alpine waters, accelerates weathering processes, and potentially triggers mobilization of pollutants. Accordingly, we monitored groundwater quantity and quality parameters of an alpine porous aquifer near the Tiefenbach glacier in the Gotthard Massif in Switzerland. The goal of this research was to assess quality and seasonal storage dynamics of groundwater above the timberline (2000 m). To translate hydrological science into an ecosystem service context, we focused on four attributes: Water quantity: observations of groundwater level fluctuations combined with analysis of contributing water sources based on stable isotope analysis to give a quantitative understanding of origin and amount of water, Water quality: groundwater level, groundwater temperature and electrical conductivity were used as proxies for sampling of hydro-chemical parameters with automated water samplers during primary groundwater recharge periods (snowmelt and rainfall events), Location: Alpine terrain above the timberline, especially recharge into/out of an alpine porous aquifer at a pro-glacial floodplain and Date of annual melt (albedo effect) and timing of flow (snow- and icemelt from May to September) and groundwater recharge during the growing season. The study found that the summer groundwater temperatures depend on the date of annual melt and are more sensitive to climate forcing than lowland groundwater temperatures. Furthermore the groundwater level determines the groundwater composition as indicated by the electric conductivity. These two observations taken together help form a better understanding of the hydrochemistry of the system, and provide useful parameters for understanding the impact of climate change on alpine groundwater.

15114506 Singhroy, Vern (Canada Center for Remote Sensing, Ottawa, ON, Canada); Li, Junhua and Charbonneau, François. High resolution rapid revisits InSAR monitoring of surface deformation [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract NH14A-04, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Monitoring surface deformation on strategic energy and transportation corridors requires high resolution spatial and temporal InSAR images for mitigation and safety purposes. High resolution air photos, lidar and other satellite images are very useful in areas where the landslides can be fatal. Recently, radar interferometry (InSAR) techniques using more rapid revisit images from several radar satellites are increasingly being used in active deformation monitoring. The Canadian RADARSAT Constellation (RCM) is a three-satellite mission that will provide rapid revisits of four days interferometric (InSAR) capabilities that will be very useful for complex deformation monitoring. For instance, the monitoring of surface deformation due to permafrost activity, complex rock slide motion and steam assisted oil extraction will benefit from this new rapid revisit capability. This paper provide examples of how the high resolution (1-3 m) rapid revisit InSAR capabilities will improve our monitoring of surface deformation and provide insights in understanding triggering mechanisms. We analysed over a hundred high resolution InSAR images over a two year period on three geologically different sites with various configurations of topography, geomorphology, and geology conditions. We show from our analysis that the more frequent InSAR acquisitions are providing more information in understanding the rates of movement and failure process of permafrost triggered retrogressive thaw flows; the complex motion of an asymmetrical wedge failure of an active rock slide and the identification of over pressure zones related to oil extraction using steam injection. Keywords: High resolution, InSAR, rapid revisits, triggering mechanisms, oil extraction.

15118578 Smith, J. P. (U. S. Naval Academy, Oceanography Department, Annapolis, MD); Suriben, R. S.; Coffin, R. B.; Boyd, T. J.; Rose, P. S.; Douglas, T. A.; Millholland, L. C., IV; Boudart, E. R. and Woods, J. E. Late-summer tundra methane concentrations and fluxes on the North Slope of Alaska [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GC11B-0560, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Scientific evidence indicates wide-scale changes in Arctic climate. The Arctic contains large expanses of tundra with permafrost, or permanently frozen subsoil. Climate change impacts on the tundra have the potential to enhance biogenic methane (CH4) production in thawed, active soils or release CH4 trapped in or below the permafrost. Methane is a highly effective greenhouse gas so CH4 released from thawing tundra or melting massive ice features constitutes a potential positive feedback to Arctic climate change. In August, 2013 the U.S. Naval Research Laboratory (NRL-6114) led an expedition to investigate late-summer tundra CH4 concentrations and fluxes on the North Slope of Alaska near Prudhoe Bay. Permafrost cores were collected to measure tundra CH4 concentrations and soil parameters and a series of gas traps were deployed to measure tundra CH4 flux at 9 locations spread across a study area of ~1800 km2. Thaw probe measurements at each site provided information on the depth of the seasonally-thawed (active) layer. Results show large differences in tundra CH4 concentrations with depth through the active layer and into the upper permafrost terrain and fine-scale variability in daily CH4 flux over a relatively small spatial area. It is likely that variations in biogeochemical and geomorphological characteristics such as soil composition, microbial activity, moisture type, active layer composition and extent from site-to-site control the CH4 regime. In order to provide more accurate estimates of permafrost tundra CH4 storage and fluxes, controls on CH4 variability from location to location must be better understood. Further research is required to quantify and predict tundra CH4 flux in order to better understand the potential impact it will have on Arctic climate, particularly if, as predicted, climate warming leads to the liberation of permafrost carbon in these landscapes.

15116817 St-Onge, Guillaume (Institut des Sciences de la Mer de Rimouski, Rimouski, QC, Canada); Lisé-Pronovost, Agathe; Gogorza, Claudia Susana; Haberzettl, Torsten; Jouve, Guillaume; Francus, Pierre; Ohlendorf, Christian; Gebhardt, Catalina and Zolitschka, Bernd. Rock-magnetic signatures of aeolian activity, precipitation and extreme runoff events from the sediments of Laguna Potrok Aike (southern Patagonia) since 51,200 cal BP [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract GP11B-04, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

The sedimentary archive from Laguna Potrok Aike is the only continuous record reaching back to the last Glacial period in continental southeastern Patagonia. Here we use high-resolution u-channel, as well as discrete rock-magnetic and physical grain size data from the 106 m long core (~51,200 cal BP) of site 2 of the ICDP Potrok Aike maar lake Sediment Archive Drilling project (PASADO) in order to develop magnetic proxies of dust and wind intensity, as well as precipitation and extreme runoff events. Rock-magnetic analyses indicate the magnetic mineral assemblage is dominated by detrital magnetite and that low field magnetic susceptibility (kLF) can be interpreted as a dust indicator in the dust source of southern Patagonia at the millennial time scale. On shorter time scales however, kLF variability is correlated to ferrimagnetic grain size and coercivity. Comparison to physical grain-size data indicates that the median destructive field of the isothermal remanent magnetisation (MDFIRM) mostly reflects medium to coarse magnetite bearing silts typically transported by winds for short-term suspension and that MDFIRM can be interpreted as a wind-intensity proxy, with stronger winds capable of transporting coarser silts to the lake. In addition, about half of the sedimentary sequence is composed of mass movement deposits (MMDs). Within these MMDs, two distinct sedimentary facies can easily be identified. The first rock-magnetic signature is detected in MMDs composed of reworked sand and tephra material. The signature consists of a gyroremanent magnetisation (GRM) acquired during demagnetisation of the natural remanent magnetisation (NRM) and other rock-magnetic properties typical of iron sulfides such as greigite. We interpret these intervals as authigenic formation of iron sulfides in suboxic conditions within the MMD. The second rock-magnetic signature consists of 10 short intervals located on the top of MMDs characterized by GRM acquisition during demagnetisation of the isothermal remanent magnetisation (IRM). These layers are interpreted as reflecting pedogenic hematite and/or goethite brought to the lake by runoff events related to precipitation and permafrost melt, and are coeval to warm periods of the last Glacial period.

15114130 Lanczont, M. (Maria Curie-Sklodowska University, Department of Geoecology and Palaeogeography, Lublin, Poland); Madeyska, T.; Komar, M. and Bogucki, A. B. The environments of loess uplands to the north and east of the Carpathians during the penultimate interglacial (MOIS 7) in palaeopedological and palaeobotanical records: in Soils and paleosols as archives of natural and anthropogenic environmental changes (Zaccone, C., editor; et al.), European Journal of Soil Science, 65(4), p. 436-454, illus. incl. strat. col., sketch map, 35 ref., July 2014. Meeting: Fourth international congress of the European Confederation of Soil Sciences Societies (ECSSS), EUROSOIL 2012, session on Soils and sediments as natural archives, July 2-6, 2012, Bari, Italy.

The stratigraphic rank of warming, distinguished in marine deposits as "marine oxygen isotope stage 7" (MOIS 7) and recorded in terrestrial deposits as a palaeosol, has been discussed for a long time. The purpose of this paper is to describe the climate and environment of the time, determined from palaeopedological and palynological investigations of loess-palaeosol sequences in the peri- and metha-Carpathian zones, and to correlate these sequences with the Pleistocene stratigraphic units. The changes in chemical composition of the deposits were used to reconstruct the processes of chemical weathering and translocation of mobile elements during pedogenesis in three sections (Orzechowce, Galych and Velykyi Glybochok). The variability of the mean annual temperature and precipitation was estimated from the changes of elemental ratios resulting from chemical weathering and vegetation composition. From micromorphological analysis, the stages of palaeosol development and their transformation in cold periods were reconstructed. Pollen analysis carried out for the Velykyi Glyboczok, Maksymivka and Stari Kodaky sites, was used to reconstruct the vegetation cover and the temperature changes of the coldest and warmest months were calculated. The results indicate that the penultimate interglacial period, correlated with MOIS 7, comprised two warming periods separated by a profound cooling period. Warm periods were cooler than the last interglacial and more recent conditions. Vegetation was characterized by the co-occurrence in changing proportions of patches of mixed forests and steppe vegetation. In the cold period, permafrost developed in places and cryogenic structures were formed. Regional differentiation of biotope environments, resulting from the increase in the continental nature of the climate towards the east, occurred during the whole interglacial period. Abstract Copyright (2013), British Society of Soil Science.

DOI: 10.1111/ejss.12111

15120714 Shingubara, Ryo (Hokkaido University, Graduate School of Environmental Science, Sapporo, Japan); Tanabe, Shinichi; Takano, Shinya; Bragin, Ivan; Murase, Jun; Tei, Shunsuke; Maximov, Trofim C. and Sugimoto, Atsuko. Mineralization rate of soil organic carbon at the lowland of Indigirka River in northeastern Siberia [abstr.]: in Japan Geoscience Union meeting 2014, Abstract - Japan Geoscience Union Meeting, 2014, 2014. Meeting: Japan Geoscience Union meeting 2014, April 28-May 2, 2014, Yokohama, Japan. Accessed on Jan. 21, 2015.

The Arctic has a large amount of organic carbon accumulated in the soil. If the enhanced warming under the Anctic amplification leads to higher soil temperature or deepening of the active layer, emission of greenhouse gases, i.e. CO₂ and CH₄ can increase. The decomposition rate of organic matter, which is an important factor of CO₂ and CH₄ emission, depends not only on the quantity of organic matter, but also on that quality. In this work, surface soils from the lowland of Indigirka river in Northeastern Siberia were incubated at constant temperatures (5, 10 °C) to evaluate the production rates of CH₄ and CO₂ and to know the degradability of the soil organic matter. The study site is around Chokurdakh (70.62 N, 147.90 E) located in the continuous permafrost of Eastern Siberia and situated in the boundary of tundra and taiga. Surface soil layers (ca. 10-60 cm deep) were sampled at 7 points of a drier mound with larch trees and of wetter areas with sedges and Sphagnum spp. Besides thawed layers (10, 20, 30 cm deep) sampled in July were incubated at Chokurdakh for 8 days anaerobically, frozen soil layers sampled in the early summer of June (13-62 cm) were incubated in Japan for 34-42 days both anaerobically and aerobically. These soils include the active layer (ca. 20-50 cm) and the top of the permafrost of this region. CH₄ production was not detected in the mound soils while CO₂ production was, suggesting areas with dry condition have few methanogens and will not produce CH₄ even if they turn into anaerobic condition. On the other hand, soils from wet areas produced CH₄ (0-0.88 mmol (g dry soil)^-1 day^-1) and the production as well as that of CO₂ was more active at the shallower layers, representing larger amount of labile organic matter. The rate of CH₄ production at 10 °C were found to be 0.9-1.1 times of that at 5 °C in the shallower layers (ca. 10-40 cm), while 1.9-3.3 times in the deeper layers (32-45 cm). It indicates that the temperature dependency of CH₄ production is higher in the middle to the bottom of the active layer than in the top layer.

URL: http://www2.jpgu.org/meeting/2014/PDF2014/2014ALL_e.pdf

15112577 Fredrick, Kyle C. (California University of Pennsylvania, Department of Earth Sciences, California, PA); Harris, Daniel B. and Fredrick, Lohny A. Investigating causes and effects of flooding on the Rock River, Lebanon Township, Dodge County, Wisconsin [abstr.]: in Geological Society of America, North-Central Section, 49th annual meeting, Abstracts with Programs - Geological Society of America, 47(5), p. 85, May 2015. Meeting: Geological Society of America, North-Central Section, 49th annual meeting, May 19-20, 2015, Madison, WI.

The Rock River, a 300-mile tributary of the Mississippi River, winds its way through the varied glacial terrain of southern Wisconsin after sourcing north of the Horicon National Wildlife Refuge, a vast marshland, important for its migratory bird habitat. Below the refuge, the Rock River is managed by several dams on its way south and west to the Illinois border. Between the dam at Horicon and the upper dam in Watertown, WI, lie the townships of Lebanon, Ashippun, and Ixonia. These mostly rural towns boast productive agricultural lands of predominantly corn, soybeans, and alfalfa. They reside in the floodplain of the river, underlain by vast expanses of outwash sands and gravels, glaciolacustrine deposits, and tills. The only significant topographic variations are the vast number of drumlins that dot the landscape. Throughout the region, spring floods are common from snowmelt and spring rain. Surface flow over frozen ground through much of the spring exacerbates annual flooding, making it a part of life for residents in the area. However, over the last 15-20 years, this segment of the Rock River has seen an increase in flooding both in periodicity and retention of flood waters. Due to the delicate habitat of the wildlife refuge and the commissioned hydroelectric installation at the upper dam in Watertown, the residents and local governments of the Lebanon/Ashippun/Ixonia segment of the river have mostly been left to their own devices to monitor and manage flood events. Lebanon Township has been recording water levels for several years, but have yet to establish a definitive explanation for the increased retention of flood waters. Data show that high water events and flood retention do not correlate well with precipitation data for the region, especially through the late spring and summer months. A stream survey was conducted from Beaver Dam to Concord to rule out obvious impediments to flow such as beaver dams, woody-debris jams, or unregulated impoundments. The survey found no significant obstructions, but evidence suggests that tributaries may be contributing sediment to the Rock River and creating deltas within the main channel. Increased development and poor soil management could exacerbate this sediment loading and increase upstream water retention.

15111768 Leduc, P. (University of Western Ontario, London, ON, Canada); Ashmore, P. and Gardner, T. Application of image texture analysis to grain sorting in a braided river physical model [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract EP52A-07, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Gravel braided rivers have complex lateral and vertical patterns of grain size sorting characterizing the river deposit and patchiness within the channel. Sorting has direct interactions with bed material transport processes for which it is important to know both the surface grain size relative to morphology and also the distribution of sizes in the morphological active layer involved in sediment transport over longer time periods. In the field, analysis of vertical sorting from direct sampling is either extremely laborious or requires long-term tracer studies of burial and mixing. We approached the problem from a new direction using a small-scale physical model of a braided channel to map bed elevation changes and grain size over time. The braided channel was developed at a slope of 1.5% and discharge of 2.1 l/s. The grain size distribution in the model is an approximately 1:30 scaled distribution of medium fluvial gravel with median size 1.3mm (D10 0.3 mm, D90 4mm). Vertical stereo images (with pixel resolution of approximately 1mm) of the dry bed were taken at one hour intervals over 40 hours of flume running time during which a large area of the river was re-worked. DEMs were derived photogrammetrically with mean elevation error of about 4mm. Surface grain size was mapped using a 7´7 pixel window and based on a calibrated relationship with the entropy values of the grey level co-occurrence matrix for the images. Consequently each pixel in the DEM also has an associated grain size. Over the 40 hour period the range of elevation and grain size variations over the river bed can be used to analyse the vertical particle-size sorting pattern within the morphological active layer (the layer between the maximum and minimum elevations at each point) and the presence of any vertical stratification in particle size. In braided channels with active bed scour and bar migration particle exchange occurs in a morphological active layer with thickness of the order of 10D90. The layer is well-mixed with no strong correlation between depth in the bed and the grain size. The size distributions of the upper-most and lower-most layers are very similar. At the flume scale, all grain sizes occur with almost equal probability over the bed depth. Reciprocally, at any bed elevation all grain sizes occur with almost equally probability.

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15111678 Sharpe, D. R. (Geological Survey of Canada, Ottawa, ON, Canada); Lesemann, J. E.; Knight, R. D.; Kjarsgaard, B. A. and Plourde, A. P. Glacial landscape architecture and sediment sampling, Mary Frances Lake - Whitefish Lake - Thelon River area (NTS 75-I, 75-J, 75-O, 75-P), Northwest Territories, Canada: Open-File Report - Geological Survey of Canada, Rep. No. 7554, 34 p., illus., 71 ref., 2014.

Erosion, transport and deposition of glacial sediment involve complex processes (Alley, 1997) that may be imperfectly recognized by exploration geologists. Thus, sediment sampling and analysis should take into account specific glacial terrain elements of mapped glacial landscapes. In this study area, in the East Arm (Sharpe et al., 2013) and in the Slave (Rampton and Sharpe, 2014) to the west, there is evidence for erosion and deposition by glacial-ice processes and by glacial-meltwater processes. Thus, to accurately assess the direction and distance of sediment transport requires consideration of multiple primary processes, and secondary (cryogenic) processes recorded in landforms (e.g. eskers, drumlinized till) and sediment attributes (e.g. striations, rounding). We suggest that targeted mineral exploration based on terrain analysis and sediment sampling of till and glaciofluvial sediment is of upmost importance in a successful mineral exploration program. This sampling plan should accommodate an assessment of the degree and effects of meltwater/ice erosion and/or deposition and integrates the findings into regional mineral-exploration strategy (e.g., Kjarsgaard et al., 2013a; Rampton and Sharpe, 2014). For example, sampling of specific sedimentary features, such as glaciofluvial forms, lags, and corridors to assess the influence of different processes of sediment transport (e.g. ice, meltwater) as well as secondary processes such as cryoturbation, could improve exploration success.

DOI: 10.4095/295461

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