13045844 Schaphoff, Sibyll (Potsdam Institute for Climate Impact Research, Potsdam, Germany); Heyder, Ursula; Ostberg, Sebastian; Gerten, Dieter; Heinke, Jens and Lucht, Wolfgang. Contribution of permafrost soils to the global carbon budget: Environmental Research Letters, 8(1), p. 014026 (10pp), illus. incl. 3 tables, sketch map, 59 ref., March 2013. Supplemental information/data is available in the online version of this article.
Climate warming affects permafrost soil carbon pools in two opposing ways: enhanced vegetation growth leads to higher carbon inputs to the soil, whereas permafrost melting accelerates decomposition and hence carbon release. Here, we study the spatial and temporal dynamics of these two processes under scenarios of climate change and evaluate their influence on the carbon balance of the permafrost zone. We use the dynamic global vegetation model LPJmL, which simulates plant physiological and ecological processes and includes a newly developed discrete layer energy balance permafrost module and a vertical carbon distribution within the soil layer. The model is able to reproduce the interactions between vegetation and soil carbon dynamics as well as to simulate dynamic permafrost changes resulting from changes in the climate. We find that vegetation responds more rapidly to warming of the permafrost zone than soil carbon pools due to long time lags in permafrost thawing, and that the initial simulated net uptake of carbon may continue for some decades of warming. However, once the turning point is reached, if carbon release exceeds uptake, carbon is lost irreversibly from the system and cannot be compensated for by increasing vegetation carbon input. Our analysis highlights the importance of including dynamic vegetation and long-term responses into analyses of permafrost zone carbon budgets. Copyright 2013 IOP Publishing Ltd
13045317 Chen Shengyun (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Cryospheric Sciences, Lanzhou, China); Liu Wenjie; Qin Xiang; Liu Yushuo; Zhang Tongzuo; Chen Kelong; Hu Fengzu; Ren Jiawen and Qin Dahe. Response characteristics of vegetation and soil environment to permafrost degradation in the upstream regions of the Shule River basin: Environmental Research Letters, 7(4), paper045406, illus. incl. 3 tables, sketch map, 52 ref., December 2012.
Permafrost degradation exhibits striking and profound influences on the alpine ecosystem, and response characteristics of vegetation and soil environment to such degradation inevitably differ during the entire degraded periods. However, up to now, the related research is lacking in the Qinghai-Tibetan Plateau (QTP). For this reason, twenty ecological plots in the different types of permafrost zones were selected in the upstream regions of the Shule River Basin on the northeastern margin of the QTP. Vegetation characteristics (species diversity, community coverage and biomass etc) and topsoil environment (temperature (ST), water content (SW), mechanical composition (SMC), culturable microorganism (SCM), organic carbon (SOC) and total nitrogen (TN) contents and so on), as well as active layer thickness (ALT) were investigated in late July 2009 and 2010. A spatial-temporal shifts method (the spatial pattern that is represented by different types of permafrost shifting to the temporal series that stands for different stages of permafrost degradation) has been used to discuss response characteristics of vegetation and topsoil environment throughout the entire permafrost degradation. The results showed that (1) ST of 0-40 cm depth and ALT gradually increased from highly stable and stable permafrost (H-SP) to unstable permafrost (UP). SW increased initially and then decreased, and SOC content and the quantities of SCM at a depth of 0-20 cm first decreased and then increased, whereas TN content and SMC showed obscure trends throughout the stages of permafrost degradation with a stability decline from H-SP to extremely unstable permafrost (EUP); (2) further, species diversity, community coverage and biomass first increased and then decreased in the stages from H-SP to EUP; (3) in the alpine meadow ecosystem, SOC and TN contents increased initially and then decreased, soil sandy fractions gradually increased with stages of permafrost degradation from substable (SSP) to transitional (TP), and to UP. Meanwhile, SOC/TN storages increased in the former stage, while they decreased in the latter stage. This study indicated that the response characteristics of vegetation and soil environment varied throughout the entire permafrost degradation, and SW was the dominant ecological factor that limited vegetation distribution and growth. Therefore, SSP and TP phases could provide a favourable environment for plant growth, mainly contributing to high SW. Copyright 2012 IOP Publishing Ltd
13045310 Forkel, Matthias (Max Planck Institute for Biogeochemistry, Biogeochemical Model-Data Integration Group, Jena, Germany); Thonicke, Kirsten; Beer, Christian; Cramer, Wolfgang; Bartalev, Sergey and Schmullius, Christiane. Extreme fire events are related to previous-year surface moisture conditions in permafrost-underlain larch forests of Siberia: Environmental Research Letters, 7(4), paper041021, illus. incl. 2 tables, sketch map, 36 ref., December 2012.
Wildfires are a natural and important element in the functioning of boreal forests. However, in some years, fires with extreme spread and severity occur. Such severe fires can degrade the forest, affect human values, emit huge amounts of carbon and aerosols and alter the land surface albedo. Usually, wind, slope and dry air conditions have been recognized as factors determining fire spread. Here we identify surface moisture as an additional important driving factor for the evolution of extreme fire events in the Baikal region. An area of 127 000 km2 burned in this region in 2003, a large part of it in regions underlain by permafrost. Analyses of satellite data for 2002-2009 indicate that previous-summer surface moisture is a better predictor for burned area than precipitation anomalies or fire weather indices for larch forests with continuous permafrost. Our analysis advances the understanding of complex interactions between the atmosphere, vegetation and soil, and how coupled mechanisms can lead to extreme events. These findings emphasize the importance of a mechanistic coupling of soil thermodynamics, hydrology, vegetation functioning, and fire activity in Earth system models for projecting climate change impacts over the next century. Copyright 2012 IOP Publishing Ltd
13046600 Lawrence, David M. (National Center for Atmospheric Research, Climate and Global Dynamics Division, NCAR Earth System Laboratory, Boulder, CO) and Swenson, Sean C. Permafrost response to increasing Arctic shrub abundance depends on the relative influence of shrubs on local soil cooling versus large-scale climate warming: Environmental Research Letters, 6(4), Citation 045504, illus. incl. 1 table, 38 ref., 2011.
Deciduous shrub abundance is increasing across the Arctic in response to climatic warming. In a recent field manipulation experiment in which shrubs were removed from a plot and compared to a control plot with shrubs, Blok et al. (2010 Glob. Change Biol. 16 1296-305) found that shrubs protect the ground through shading, resulting in a ~9% shallower active layer thickness (ALT) under shrubs compared to grassy-tundra, which led them to argue that continued Arctic shrub expansion could mitigate future permafrost thaw. We utilize the Community Land Model (CLM4) coupled to the Community Atmosphere Model (CAM4) to evaluate this hypothesis. CLM4 simulates shallower ALT (~-11 cm) under shrubs, consistent with the field manipulation study. However, in an idealized pan-Arctic +20% shrub area experiment, atmospheric heating, driven mainly by surface albedo changes related to protrusion of shrub stems above the spring snowpack, leads to soil warming and deeper ALT (~+10 cm). Therefore, if climate feedbacks are considered, shrub expansion may actually increase rather than decrease permafrost vulnerability. When we account for blowing-snow redistribution from grassy-tundra to shrubs, shifts in snowpack distribution in low versus high shrub area simulations counter the climate warming impact, resulting in a grid cell mean ALT that is unchanged. These results reinforce the need to consider vegetation dynamics and blowing-snow processes in the permafrost thaw model projections. Copyright IOP Publishing Ltd
13046598 Yi Shuhua (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Cryosphere Sciences, Lanzhou, China); Zhou Zhaoye; Ren Shilong; Xu Ming; Qin Yu; Chen Shengyun and Ye Baisheng. Effects of permafrost degradation on alpine grassland in a semi-arid basin on the Qinghai-Tibetan Plateau: Environmental Research Letters, 6(4), Citation 045403, illus. incl. 2 tables, sketch map, 20 ref., 2011.
Permafrost on the Qinghai-Tibetan Plateau (QTP) has degraded over the last few decades. Its ecological effects have attracted great concern. Previous studies focused mostly at plot scale, and hypothesized that degradation of permafrost would cause lowering of the water table and drying of shallow soil and then degradation of alpine grassland. However, none has been done to test the hypothesis at basin scale. In this study, for the first time, we investigated the relationships between land surface temperature (LST) and fractional vegetation cover (FVC) in different types of permafrost zone to infer the limiting condition (water or energy) of grassland growth on the source region of Shule River Basin, which is located in the north-eastern edge of the QTP. LST was obtained from MODIS Aqua products at 1 km resolution, while FVC was upscaled from quadrat (50 cm) to the same resolution as LST, using 30 m resolution NDVI data of the Chinese HJ satellite. FVC at quadrat scale was estimated by analyzing pictures taken with a multi-spectral camera. Results showed that (1) retrieval of FVC at quadrat scale using a multi-spectral camera was both more accurate and more efficient than conventional methods and (2) the limiting factor of vegetation growth transitioned from energy in the extreme stable permafrost zone to water in the seasonal frost zone. Our study suggested that alpine grassland would respond differently to permafrost degradation in different types of permafrost zone. Future studies should consider overall effects of permafrost degradation, and avoid the shortcomings of existing studies, which focus too much on the adverse effects. Copyright IOP Publishing Ltd
13046574 Zhang, Ningning (Nagoya University, Graduate School of Environmental Studies, Nagoya, Japan); Yasunari, Tetsuzo and Ohta, Takeshi. Dynamics of the larch taiga-permafrost coupled system in Siberia under climate change: Environmental Research Letters, 6(2), Citation 024003, illus., 30 ref., 2011.
Larch taiga, also known as Siberian boreal forest, plays an important role in global and regional water-energy-carbon (WEC) cycles and in the climate system. Recent in situ observations have suggested that larch-dominated taiga and permafrost behave as a coupled eco-climate system across a broad boreal zone of Siberia. However, neither field-based observations nor modeling experiments have clarified the synthesized dynamics of this system. Here, using a new dynamic vegetation model coupled with a permafrost model, we reveal the processes of interaction between the taiga and permafrost. The model demonstrates that under the present climate conditions in eastern Siberia, larch trees maintain permafrost by controlling the seasonal thawing of permafrost, which in turn maintains the taiga by providing sufficient water to the larch trees. The experiment without permafrost processes showed that larch would decrease in biomass and be replaced by a dominance of pine and other species that suffer drier hydroclimatic conditions. In the coupled system, fire not only plays a destructive role in the forest, but also, in some cases, preserves larch domination in forests. Climate warming sensitivity experiments show that this coupled system cannot be maintained under warming of about 2°C or more. Under such conditions, a forest with typical boreal tree species (dark conifer and deciduous species) would become dominant, decoupled from the permafrost processes. This study thus suggests that future global warming could drastically alter the larch-dominated taiga-permafrost coupled system in Siberia, with associated changes of WEC processes and feedback to climate. Copyright IOP Publishing Ltd
13050811 Yang Meixue (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Laboratory of Cryospheric Sciences, Lanzhou, China); Nelson, Frederick E.; Shiklomanov, Nikolay I.; Guo Donglin and Wan Guoning. Permafrost degradation and its environmental effects on the Tibetan Plateau; a review of recent research: Earth-Science Reviews, 103(1-2), p. 31-44, illus. incl. 3 tables, sketch maps, 138 ref., November 2010. Includes appendices.
A significant portion of the Tibetan Plateau is underlain by permafrost, and is highly sensitive to climate change. Observational data from recent Chinese investigations on permafrost degradation and its environmental effects in the Tibetan region indicate that a large portion of the Tibetan Plateau has experienced significant warming since the mid-1950s. The air temperature increase is most significant in the central, eastern, and northwestern parts of the Plateau. The warming trend in the cold season was greater than that in the warm season. The duration of seasonal ground freezing has shortened due to the air temperature increase in winter. Numerical simulations indicate that air temperature on the Plateau will continue to increase in the 21st century. Significant warming has resulted in extensive degradation of permafrost. Over the last 30 years, a 25 m increase in the lower altitudinal occurrences of permafrost has taken place in the north. In the south the increase is 50-80 m over the past 20 years. Active-layer thickness and mean annual ground temperature have increased by 0.15-0.50 m during 1996-2001 and by 0.1-0.5°C during the last 30 years on the Tibetan Plateau, respectively. Widespread permafrost degradation has already caused environmental deterioration. Extensive desertification processes are apparent in the eastern and western portions of the Tibetan Plateau, with the area occupied by desert increasing annually by about 1.8%. With rapid retreat and thinning of permafrost, large carbon pools sequestered in permafrost could be released to increase net sources of atmospheric carbon, creating a positive feedback and accelerated warming. Damage to human infrastructure is also caused by frost heave, thaw settlement, and thaw slumping in the permafrost-affected region. The impact of permafrost degradation on energy and water exchange processes between the ground and atmosphere require further examination. Large-scale intensive monitoring networks, remote sensing investigations, and models for frozen soil are needed to clarify regional details of climate change, permafrost degradation, and their environmental effects. Abstract Copyright (2010) Elsevier, B.V.
13047024 Rödder, T. and Kneisel, Christof. Permafrost mapping using quasi-3D resistivity imaging, Murtèl, Swiss Alps: Near Surface Geophysics, 10(2), p. 117-127, 35 ref., April 2012.
13052002 Lenz, Josefine (Alfred Wegener Institute for Polar and Marine Research, Department of Periglacial Research, Potsdam, Germany); Fritz, Michael; Schirrmeister, Lutz; Lantuit, Hugues; Wooller, Matthew J.; Pollard, Wayne H. and Wetterich, Sebastian. Periglacial landscape dynamics in the western Canadian Arctic; results from a thermokarst lake record on a push moraine (Herschel Island, Yukon Territory): Palaeogeography, Palaeoclimatology, Palaeoecology, 381-382, p. 15-25, illus. incl. 2 tables, sketch map, 77 ref., July 2013.
Ice-rich permafrost landscapes are sensitive to climate and environmental change due to the melt-out of ground ice during thermokarst development. Thermokarst processes in the northern Yukon Territory are currently not well-documented. Lake sediments from Herschel Island (69°36'N; 139°04'W) in the western Canadian Arctic provide a record of thermokarst lake development since the early Holocene. A 727 cm long lake sediment core was analyzed for radiographic images, magnetic susceptibility, granulometry, and biogeochemical parameters (organic carbon, nitrogen, and stable carbon isotopes). Based on eight calibrated AMS radiocarbon dates, the sediment record covers the last ~11,500 years and was divided into four lithostratigraphic units (A to D) reflecting different thermokarst stages. Thermokarst initiation at the study area began ~11.5 cal ka BP. From ~11.5 to 10.0 cal ka BP, lake sediments of unit A started to accumulate in an initial lake basin created by melt-out of massive ground ice and thaw subsidence. Between 10.0 and 7.0 cal ka BP (unit B) the lake basin expanded in size and depth, attributed to talik formation during the Holocene thermal maximum. Higher-than-modern summer air temperatures led to increased lake productivity and widespread terrain disturbances in the lake's catchment. Thermokarst lake development between 7.0 and 1.8 cal ka BP (unit C) was characterized by a dynamic equilibrium, where lake basin and talik steadily expanded into ambient ice-rich terrain through shoreline erosion. Once lakes become deeper than the maximum winter lake ice thickness, thermokarst lake sediments show a great preservation potential. However, site-specific geomorphic factors such as episodic bank-shore erosion or sudden drainage through thermo-erosional valleys or coastal erosion breaching lake basins can disrupt continuous deposition. A hiatus in the record from 1.8 to 0.9 cal ka BP in Lake Herschel likely resulted from lake drainage or allochthonous slumping due to collapsing shore lines before continuous sedimentation of unit D recommenced during the last 900 years. Abstract Copyright (2013) Elsevier, B.V.
13045302 Cannone, Nicoletta (Insubria University, Department of Theoretical and Applied Sciences, Como, Italy); Binelli, Giorgio; Worland, M. Roger; Convey, Peter and Guglielmin, Mauro. CO2 fluxes among different vegetation types during the growing season in Marguerite Bay (Antarctic Peninsula): Geoderma, 189-190, p. 595-605, illus. incl. 3 tables, sketch map, 71 ref., November 2012.
The Antarctic Peninsula has experienced a strong climate warming trend of +0.53°C (mean annual air temperature) over the last 50 years. In the Polar Regions, changes in vegetation and permafrost due to a warming climate are expected to produce strong feedbacks to climate and, despite their relatively small areal extent, ice-free areas in Antarctica provide unique natural environments for studying these effects. Off the Antarctic Peninsula, close to Rothera Research Station on Adelaide Island, we used in situ measurements to assess whether spatial variation of CO2 fluxes exists a) among three important and typical vegetation types at Rothera Point during the daylight period; b) across four different ecosystem types (from Antarctic vascular tundra to barren soil) on neighbouring Anchorage Island during the peak of the growing season (January-February 2009). We aimed to assess whether Net Ecosystem Exchange (NEE), Ecosystem Respiration (ER) and Gross Ecosystem Photosynthesis (GEP) change among the selected ecosystem types and determine which environmental factors (soil moisture, soil temperature and PAR) influence NEE and ER. The data obtained at Rothera Point confirmed the presence of spatial variation of CO2 fluxes related to vegetation type, and temporal variation of the CO2 cycle during the daylight period for moss and barren soil ecosystems. At Anchorage Island the spatial variation of CO2 fluxes was mainly influenced by vegetation type at inter-community level. Deschampsia and Sanionia showed higher NEE and ER values (-0.03/0.43mmol CO2 m-2s-1 for Deschampsia NEE; 0/0.62mmol CO2 m-2s-1Sanionia NEE; 0.27/2.03mmol CO2 m-2s-1Deschampsia ER; 0.31/1.7mmol CO2 m-2s-1Sanionia ER) than the other vegetation types studied. We measured generally positive NEE values probably due to high soil respiration. Our data suggest that ecosystems such as those studied may act as a source for CO2 release to the atmosphere and that this source effect is likely to continue and/or to increase until the "legacy" of organic matter and nutrients stored in the soils is largely decomposed. Abstract Copyright (2012) Elsevier, B.V.
13046621 Semiletov, Igor P. (University of Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK); Shakhova, Natalia E.; Sergienko, Valentin I.; Pipko, Irina I. and Dudarev, Oleg V. On carbon transport and fate in the East Siberian Arctic land-shelf-atmosphere system: Environmental Research Letters, 7(1), Citation 015201, illus. incl. sketch maps, 78 ref., March 2012.
This review paper summarizes current understanding of the transport of organic carbon to, and the fate of organic carbon within, the East Siberian Arctic Shelf (ESAS), and of processes determining carbon dioxide (CO2) and methane (CH4) fluxes from the ESAS to the atmosphere achieved from analyzing the data sets obtained on 20 expeditions performed from 1999 to 2011. This study of the ESAS was aimed at investigating how redistribution of old carbon from degrading terrestrial and sub-sea permafrost and from coastal erosion contributes to the carbon pool of the ESAS, how changes in the hydrological cycle of the surrounding land and alteration of terrestrial carbon cycles affect the hydrological and biogeochemical parameters of shelf water masses, and which factors control CH4 and CO2 emissions from the ESAS. This report describes selected results achieved by a developing international scientific partnership that has been crucial at every stage of the study and will be even more important in the future. Copyright 2012 IOP Publishing Ltd
13047003 Occhiena, C. (Istituto di Ricerca per la Protezione Idrogeologica, Torino, Italy); Coviello, V.; Arattano, M.; Chiarle, M.; Morra di Cella, U.; Pirulli, M.; Pogliotti, P. and Scavia, C. Analysis of microseismic signals and temperature recordings for rock slope stability investigations in high mountain areas: Natural Hazards and Earth System Sciences (NHESS), 12(7), p. 2283-2298, 17 ref., 2012.
The permafrost degradation is a probable cause for the increase of rock instabilities and rock falls observed in recent years in high mountain areas, particularly in the Alpine region. The phenomenon causes the thaw of the ice filling rock discontinuities; the water deriving from it subsequently freezes again inducing stresses in the rock mass that may lead, in the long term, to rock falls. To investigate these processes, a monitoring system composed by geophones and thermometers was installed in 2007 at the Carrel hut (3829 m a.s.l., Matterhorn, NW Alps). In 2010, in the framework of the Interreg 2007-2013 Alcotra project no. 56 MASSA, the monitoring system has been empowered and renovated in order to meet project needs. In this paper, the data recorded by this renewed system between 6 October 2010 and 5 October 2011 are presented and 329 selected microseismic events are analysed. The data processing has concerned the classification of the recorded signals, the analysis of their distribution in time and the identification of the most important trace characteristics in time and frequency domain. The interpretation of the results has evidenced a possible correlation between the temperature trend and the event occurrence. The research is still in progress and the data recording and interpretation are planned for a longer period to better investigate the spatial-temporal distribution of microseismic activity in the rock mass, with specific attention to the relation of microseismic activity with temperatures. The overall goal is to verify the possibility to set up an effective monitoring system for investigating the stability of a rock mass under permafrost conditions, in order to supply the researchers with useful data to better understand the relationship between temperature and rock mass stability and, possibly, the technicians with a valid tool for decision-making.
13050462 French, Hugh (University of Ottawa, Department of Geography, Ottawa, ON, Canada) and Shur, Yuri. The principles of cryostratigraphy: Earth-Science Reviews, 101(3-4), p. 190-206, illus. incl. 4 tables, 75 ref., August 2010.
Cryostratigraphy adopts concepts from both Russian geocryology and modern sedimentology. Structures formed by the amount and distribution of ice within sediment and rock are termed cryostructures. Typically, layered cryostructures are indicative of syngenetic permafrost while reticulate and irregular cryostructures are indicative of epigenetic permafrost. 'Cryofacies' can be defined according to patterns of sediment characterized by distinct ice lenses and layers, volumetric ice content and ice-crystal size. Cryofacies can be subdivided according to cryostructure. Where a number of cryofacies form a distinctive cryostratigraphic unit, these are termed a 'cryofacies assemblage'. The recognition, if present, of (i) thaw unconformities, (ii) other ice bodies such as vein ice (ice wedges), aggradational ice and thermokarst-cave ('pool') ice, and (iii) ice, sand and gravelly pseudomorphs is also important in determining the nature of the freezing process, the conditions under which frozen sediment accumulates, and the history of permafrost. Abstract Copyright (2010) Elsevier, B.V.
13045912 Seppi, Roberto (Universita di Pavia, Dipartimento di Scienze della Terra e dell'Ambiente, Pavia, Italy); Carton, Alberto; Zumiani, Matteo; Dall'Amico, Matteo; Zampedri, Giorgio and Rigon, Riccardo. Inventory, distribution and topographic features of rock glaciers in the southern region of the eastern Italian Alps (Trentino): Geografia Fisica e Dinamica Quaternaria (Testo Stampato), 35(2), p. 185-197 (Italian sum.), illus. incl. 3 tables, geol. sketch map, 75 ref., 2012. (Bollettino del Comitato Glaciologico Italiano, Ser. 3).
A GIS-based rock glacier inventory was conducted in a region of about 6200 km2 located in the southern sector of the Eastern Italian Alps (Trentino). The five major mountain groups of the region were investigated and a total of 705 rock glaciers, 25% of which are intact (i.e. containing permafrost), were identified. Their spatial distribution is rather inhomogeneous, which suggests that, in addition to climate, the bedrock lithology and structure are among the key factors controlling their genesis and development. The lowest density of rock glaciers was associated with carbonatic rock outcroppings (e.g. in the Brenta Group and in the Dolomites), whereas the highest density was observed in arcas dominated by metamorphic rocks (e.g. Ortles Cevedale group). The rock glaciers cover a total area of 33.3 km2, which is more than 1.4% of the area located above 1600 m a.s.l. and is comparable to the area covered by glaciers (38.3 km2 in 2003). The rock glaciers are located at a mean elevation of 2282±289 m a.s.l. and are distributed in an elevation range of about 1440 m. Considering separately the two classes of intact and relict (i.e. with no permafrost) rock glaciers, the mean elevation is 2632±205 m a.s.l. and 2169±211 m a.s.l. respectively. Relict rock glaciers are found between 1650 and 2700 m a.s.l., whereas above 2800 m a.s.l. only intact rock glaciers exist. The mean aspect of all the inventoried rock glaciers is 43°. A dominant northern orientation does not emerge in the class of the intact forms, whereas the relict rock glaciers show a predominant northern orientation with a mean aspect of about 30°. According to the mean elevation of the intact rock glaciers, the lower boundary of permafrost in the studied region would be located at an elevation of approximately 2630 m a.s.l. This boundary varies significantly when considering the different exposures, and ranges from about 2510 m a.s.l. on north-facing slopes to about 2690 m a.s.l. on those exposed to the south. The lower boundary of permafrost existence in the past, as marked by the mean elevation of the relict rock glaciers, was located about 450 m lower than the modern one with variations included in a range of 230 m according to the exposure. This provides a rough estimation of the shift in elevation of the lower permafrost boundary between the present-day and the time when the relict rock glaciers were active. Accordingly, a MAAT increase of about 2.9°C can be calculated applying a standard vertical lapse rate (0.65°C/100 m) to this shift.
13044848 Williams, George E. (University of Adelaide, Discipline of Geology and Geophysics, Adelaide, South Aust., Australia); Gostin, Victor A.; McKirdy, David M.; Preiss, Wolfgang V. and Schmidt, Philip W. The Elatina Glaciation (late Cryogenian), South Australia: in The geological record of Neoproterozoic glaciations (Arnaud, Emmanuelle, editor; et al.), Memoirs of the Geological Society of London, 36, p. 713-721, illus. incl. sect., geol. sketch map, 90 ref., 2011. (Lyell Collection). Supplemental information/data is available at URL: http://www.geolsoc.org.uk/SUP18481. IGCP Project No. 512.
Deposits of the late Cryogenian Elatina glaciation constitute the Yerelina Subgroup in the Adelaide Geosyncline region, South Australia. They have a maximum thickness of c. 1500 m, cover 200 000 km2, and include the following facies: basal boulder diamictite with penetrative glaciotectonites affecting preglacial beds; widespread massive and stratified diamictites containing faceted and striated clasts, some derived from nearby emergent diapiric islands and others of extrabasinal provenance; laminated siltstone and mudstone with dropstones; tidalites and widespread glaciofluvial, deltaic to marine-shelf sandstones; a regolith of frost-shattered quartzite breccia up to 20 m thick that contains primary sand wedges 3+ m deep and other large-scale periglacial forms; and an aeolian sand sheet covering 25 000 km2 and containing primary sand wedges near its base. These deposits mark a spectrum of settings ranging from permafrost regolith and periglacial aeolian on the cratonic platform (Stuart Shelf) in the present west, through glaciofluvial, marginal-marine and inner marine-shelf in the central parts of the Adelaide Geosyncline, to outer marine-shelf in sub-basins in the present SE and north. The Elatina glaciation has not been dated directly, and only maximum and minimum age limits of c. 640 and 580 Ma, respectively, are indicated. Palaeomagnetic data for red beds from the Elatina Formation (Fm.) and associated strata indicate deposition of the Yerelina Subgroup within 10° of the palaeoequator. The Yerelina Subgroup is unconformably to disconformably overlain by the dolomitic Nuccaleena Fm., which in most places is the lowest unit of the Wilpena Group and marks Early Ediacaran marine transgression.
13050461 Evans, David J. A. (Durham University, Department of Geography, Durham, United Kingdom) and Thomson, Stephen A. Glacial sediments and landforms of Holderness, eastern England; a glacial depositional model for the North Sea Lobe of the British-Irish ice sheet: Earth-Science Reviews, 101(3-4), p. 147-189, illus. incl. 2 tables, sketch maps, 90 ref., August 2010.
Borehole records and exposures at coastal cliffs and inland quarries around Holderness are used in a critical assessment of the glacial depositional environments that operated at the margin of the North Sea lobe of the British-Irish Ice Sheet at the Last Glacial Maximum. Four lithofacies associations (LFA) are recognized in the area: LFAs 1 and 4 are laminated to massive diamictons, traditionally called the Skipsea and Withernsea tills/members, and display deformation structures indicative of stress from the NE, attenuated rafts of soft bedrock lithologies, ice-bed separation (canal fill) features and pseudo-stratification, and clast macrofabric data predominantly indicate deformation only to low strains. They are interpreted as subaqueous deposits subsequently deformed by glacier ice to create end products that lie on the glacitectonite continuum. Localized increases in strain signature are equated with the development of shear zones between onshore thickening wedges of deformed, pre-existing lake sediment. LFA 2 comprises cross-bedded clinoforms, locally steepening into foresets, at the core of linear hummocks along the central spine of Holderness (LFA 2a) and rhythmically laminated silts and sands with dropstones (LFA 2b). These sediments are interpreted as coalescent glacilacustrine subaqueous outwash fans, fining distally to lake bottom rhythmites and varves. Ice-contact deposition is evident in compressional folding, faulting and hydrofracture filling due to ice overriding, and extensional faulting associated with localized ice melt-out. Depressions produced by folding or sagging provided the accommodation space for the later deposition of LFA 2 and 3 through syntectonic sedimentation. LFA 3 comprises flat-lying beds of well to poorly sorted cross-stratified sands and gravels, interpreted as proximal proglacial braided outwash deposits laid down largely in ribbon sandar defined by the topography of abandoned ice-contact glacilacustrine depo-centres. Well developed ice wedge pseudomorphs in LFA 3 record permafrost conditions during ice sheet marginal recession, indicating that North Sea lobe oscillations may have been non-climatic or surge related. A depositional model is proposed in which "advance" and "retreat" phase tills/glacitectonites and associated ice-contact lake sediments are the geological imprint of a single glaciation. The initial advance of the North Sea lobe is recorded by a westerly thinning advance till (LFA 1). Later LFA 1 and 4 retreat "tills" are strictly glacitectonites, and are thicker depositional units because later ice readvances encroached upon and cannibalized more substantial sequences of deglacial lake sediment and subaqueous ice-contact fans (LFA 2). Similar regional till architectures will be manifest wherever the palaeogeography resulted in the onshore flow of ice and the concomitant production of glacitectonites from glacial lake sediments. Abstract Copyright (2010) Elsevier, B.V.
13049507 Yang Yong (Chinese Academy of Sciences, Cold and Arid Region Environment and Engineering Research Institute, Heihe Upstream Watershed Ecology-Hydrology Experimental Research Station, Lanzhou, China); Chen Rensheng; Han Chuntan and Qing Wenwu. Measurement and estimation of the summertime daily evapotranspiration on alpine meadow in the Qilian Mountains, northwest China: Environmental Earth Sciences, 68(8), p. 2253-2261, illus. incl. 1 table, sketch map, 36 ref., April 2013.
Research on mountain evapotranspiration (ET) is important to help understand water cycling and predict streamflow in cold regions in China. Actual daily ET was measured in two types of micro-lysimeters with depth 40 cm and diameter 31.5 cm (A) and depth 27 cm and diameter 27 cm (B), from 1 July 2007 to 10 September 2007, on an alpine meadow in the Qilian Mountains in northwest China, where Bowen ratio measuring instrument and eddy covariance system are too costly and difficult to be built in the region. The results of micro-lysimeters were used as a way to calibrate and test a number of energy balance methods and determine the pan coefficient (K p) for a mountainous site. The results indicate that the FAO-56 Penman-Monteith offers the best performance, with RMSE of 0.61 mm day-1, MAD of 0.46 mm day-1, and the index of agreement near 1, followed by ASCE Penman-Monteith, Priestley-Taylor and Hargreaves-Samani, and the K p is estimated as 0.7 for the summertime. Copyright 2013 Springer-Verlag Berlin Heidelberg and 2012 Springer-Verlag
13045313 Matsumura, Shinji (Hokkaido University, Faculty of Environmental Earth Science, Sapporo, Japan) and Yamazaki, Koji. A longer climate memory carried by soil freeze-thaw processes in Siberia: Environmental Research Letters, 7(4), paper045402, illus. incl. sketch maps, 21 ref., December 2012.
The climate memory of a land surface generally persists for only a few months, but analysis of surface meteorological data revealed a longer-term climate memory carried by soil freeze-thaw processes in Siberia. Surface temperature variability during the snowmelt season corresponds reasonably well with that in the summer of the following year, when most stations show a secondary autocorrelation peak. The surface temperature memory is thought to be stored as variations in the amount of snowmelt water held in the soil, and through soil freezing, which emerges as latent heat variations in the near-surface atmosphere during soil thawing approximately one year later. The ground conditions are dry in the longer-term climate memory regions, such as eastern Siberia, where less snow cover (higher surface air temperature) in spring results in less snowmelt water or lower soil moisture in the summer. Consequently, through soil freezing, it will require less latent heat to thaw in the summer of the following year, resulting in higher surface air temperature. In addition to soil moisture and snow cover, soil freeze-thaw processes can also act as agents of climate memory in the near-surface atmosphere. Copyright 2012 IOP Publishing Ltd
13046622 Gamon, John A. (University of Alberta, Department of Earth and Atmospheric Sciences, Edmonton, AB, Canada); Kershaw, G. Peter; Williamson, Scott and Hik, David S. Microtopographic patterns in an arctic baydjarakh field; do fine-grain patterns enforce landscape stability?: Environmental Research Letters, 7(1), Citation 015502, illus. incl. 1 table, 32 ref., March 2012.
Recent observations suggest that while some arctic landscapes are undergoing rapid change, others are apparently more resilient. In this study, we related surface cover and energy balance to microtopography in a degraded polygonal peat plateau (baydjarakh field) near Churchill, Manitoba in mid-summer 2010. The landscape consists of remnant high-centered polygons divided by troughs of varying widths. Historical aerial photos indicate these topographical features have been stable for over 80 years. Our goal was to explore patterns that might explain the apparent stability of this landscape over this time period and to evaluate remote sensing methods for characterizing microtopographic patterns that might resist change in the face of climate warming. Summertime surface albedo measurements were combined with several years of winter snow depth, snow heat flux, summer thaw depth and annual surface temperature, all of which had striking contrasts between wet troughs and high polygon centers. Measurements of albedo and the snowpack heat transfer coefficient were lowest for wet troughs (areas of standing water) dominated by graminoids, and were significantly higher for high polygon centers, dominated by dwarf shrubs and lichens. Snow depth, surface temperature and thaw depth were all significantly higher for wet troughs than high polygon centers. Together these patterns of cover and energy balance associated with microtopographic variation can contribute to the stability of this landscape through differential heat transfer and storage. We hypothesize that local thermal feedback effects, involving greater heat trapping in the troughs than on the baydjarakh tops, and effective insulation on the baydjarakh edges, have ensured landscape stability over most of the past century. These results suggest that high-resolution remote sensing, combined with detailed field monitoring, could provide insights into the dynamics or stability of arctic landscapes, where cover often varies over short distances due to microtopographic effects. Copyright IOP Publishing Ltd
13046554 Karlsson, Johanna Mard (Stockholm University, Department of Physical Geography and Quaternary Geology, Stockholm, Sweden); Bring, Arvid; Peterson, Garry D.; Gordon, Line J. and Destouni, Georgia. Opportunities and limitations to detect climate-related regime shifts in inland Arctic ecosystems through eco-hydrological monitoring: Environmental Research Letters, 6(1), Citation 014015, illus. incl. sketch maps, 60 ref., 2011.
This study has identified and mapped the occurrences of three different types of climate-driven and hydrologically mediated regime shifts in inland Arctic ecosystems: (i) from tundra to shrubland or forest, (ii) from terrestrial ecosystems to thermokarst lakes and wetlands, and (iii) from thermokarst lakes and wetlands to terrestrial ecosystems. The area coverage of these shifts is compared to that of hydrological and hydrochemical monitoring relevant to their possible detection. Hotspot areas are identified within the Yukon, Mackenzie, Barents/Norwegian Sea and Ob river basins, where systematic water monitoring overlaps with ecological monitoring and observed ecosystem regime shift occurrences, providing opportunities for linked eco-hydrological investigations that can improve our regime shift understanding, and detection and prediction capabilities. Overall, most of the total areal extent of shifts from tundra to shrubland and from terrestrial to aquatic regimes is in hydrologically and hydrochemically unmonitored areas. For shifts from aquatic to terrestrial regimes, related water and waterborne nitrogen and phosphorus fluxes are relatively well monitored, while waterborne carbon fluxes are unmonitored. There is a further large spatial mismatch between the coverage of hydrological and that of ecological monitoring, implying a need for more coordinated monitoring efforts to detect the waterborne mediation and propagation of changes and impacts associated with Arctic ecological regime shifts. Copyright IOP Publishing Ltd
13050858 Gubin, S. V. (Russian Academy of Sciences, Institute of Physicochemical and Biological Problems of Soil Science, Pushchino, Russian Federation) and Veremeeva, A. A. Parent materials enriched in organic matter in the northeast of Russia: Eurasian Soil Science, 43(11), p. 1238-1243, illus. incl. , 21 ref., November 2010. Based on Publisher-supplied data.
The distribution, development, and properties of the sedimentary parent materials in the northeastern sector of the Russian Arctic and Subarctic regions are discussed. Vast areas in this sector are occupied by deposits of the Ice Complex that were formed in the Late Pleistocene and have been preserved in the frozen state up to the present time. The processes of synlithogenic pedogenesis took an active part in the formation of these deposits; owing to them, the sediments are enriched in organic matter. A larger part of this organic matter is represented by fine plant detritus. In the course of the thermokarst processes and partial thawing of these deposits in the Holocene, the organic matter content in the upper part of the Ice Complex has somewhat decreased, and its qualitative composition has changed. The soil profiles developing from these deposits inherit the relict organic matter. Copyright 2010 Pleiades Publishing, Ltd.
13050568 Rowe, Mark and O'Dwyer, Gerard. The future of energy; under the frost?: Petroleum Review (London, 1968), 64(763), p. 34-35, illus., August 2010.
13052009 Bockheim, J. G. (University of Wisconsin at Madison, Department of Soil Science, Madison, WI). Soil formation in the Transantarctic Mountains from the middle Paleozoic to the Anthropocene: Palaeogeography, Palaeoclimatology, Palaeoecology, 381-382, p. 98-109, illus. incl. 3 tables, sketch map, 56 ref., July 2013.
In the Transantarctic Mountains (TAMs), soils from the middle Paleozoic and from the Oligocene to the present have been examined. Soils representing other sections of the geologic column are missing, probably because of the low proportion of ice-free areas (0.35%) in Antarctica. The evolution of soils in Antarctica reflects changes in climate and geologic conditions as the continent became separated and increasingly isolated from Gondwana. A greenhouse climate existed during the middle Paleozoic; and an icehouse climate began in the early Oligocene. The climate of the TAMs has become increasingly hyper-arid since the middle Miocene. Humans have had a dramatic effect on the climate of the TAMs during the Anthropocene. The first forest soils (under Callixylon-Archaeopteris forest) on Earth, identified as Alfisols, were discovered in Antarctica and assigned to the middle Devonian. During the Permian, Dicroidium forests covered Entisols and Inceptisols. In the Oligocene, Nothofagus-Podocarpaceae forests contained Gelisols. Miocene-aged soils enriched in silt are common in the TAMs, but they tend to be poorly developed because they have been eroded. A soil evolutionary sequence exists in the TAMs from the Holocene through the Pliocene that includes Glacic Haploturbels on ice-cored Holocene drift, Typic Haploturbels on late Pleistocene surfaces, Typic Anhyorthels on middle Pleistocene surfaces, Salic Anhyorthels on early Pleistocene surfaces, and Petrosalic Anhyorthels on Pliocene surfaces. These changes reflect gradual sublimation of ice in ice-cored drift and ice-wedge polygons, a recovery of the surface from cryoturbation, accumulation of salts, and eventual development of a salt pan. Soils of the TAMs are undergoing rapid change as the climate warms, including loss of semi-permanent snowbanks, an expansion of the hyporheic zone, flushing of salts from soils along valley walls, and the development of thermokarst. Abstract Copyright (2013) Elsevier, B.V.
13049632 Hooke, Roger LeB. (University of Maine, School of Earth and Climate Sciences and Climate Change Institute, Orono, ME) and Medford, Aaron. Are drumlins a product of a thermo-mechanical instability?: Quaternary Research, 79(3), p. 458-464, illus., 49 ref., May 2013.
Of numerous theories of drumlin genesis, none has been widely accepted. It seems evident, however, that some form of positive feedback process is involved. Under certain circumstances perturbations are amplified. Herein we suggest that patchy areas of frozen bed provide the initial perturbation. Such frozen patches may occur in local areas underlain by material of lower thermal conductivity or on slight topographic highs. Drag exerted by the frozen patch deflects ice flow into its lee, dragging with it mobile till eroded from the thawed area. The energy balance is such that this till likely refreezes, either producing a topographic perturbation or amplifying an existing one. The resulting topography then deflects more of the geothermal heat away from the developing hill and into the adjacent trough, resulting in a positive feedback. Once the thermal perturbation exceeds a critical (though as yet undefined) level, melting may decouple the ice from the bed, preventing further entrainment of till from thawed areas, and thus limiting the height and length of the drumlin. Abstract Copyright (2013) Elsevier, B.V.
13049568 Pandey, Priyanka (McGill University, Department of Bioresource Engineering, Montreal, QC, Canada); Gleeson, Tom and Baraer, Michel. Toward quantifying discrete groundwater discharge from frozen seepage faces using thermal infrared images: Geophysical Research Letters, 40(1), p. 123-127, illus., 30 ref., January 16, 2013.
Frozen groundwater seeps from discrete features, such as fractures and faults, are common along steep faces of cliffs, mines, quarries, and road cuts in cold environments at high elevations and latitudes. Our objective is to test whether thermal infrared imaging can be used to quantify groundwater discharge from such discrete features in freezing conditions. Discrete seeps and freezing cliff faces were simulated in a cold room laboratory with a systematic series of experiments captured through infrared imaging. Two zones of distinct surface temperatures were observed at the ice surface: a zone of relatively warm and constant surface temperature above a zone with high thermal gradients. Experimental conditions impacted the length of the relative warm zone. A strong correlation is observed between length of the relative warm zone and the discharge rate suggesting that groundwater discharge from discrete features could be quantified using noninvasive infrared imaging. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.
13045240 Backnas, Soile (University of Oulu, Water Resources and Environmental Engineering Laboratory, Oulu, Finland); Laine-Kaulio, Hanne and Klove, Bjorn. Phosphorus forms and related soil chemistry in preferential flowpaths and the soil matrix of a forested podzolic till soil profile: Geoderma, 189-190, p. 50-64, illus. incl. 7 tables, 100 ref., November 2012.
Preferential flow affects subsurface flow and solute transport processes in forested glacial till soils. Preferential flowpaths (PFPs) have been detected in forest soils, with higher microbial biomass, organic carbon content and increased nitrogen cycling compared with the soil matrix. However, the role of preferential flow in phosphorus (P) cycling in forest soils is still unknown. This study characterised the P forms of a forested podzolic till soil profile in Southern Finnish Lapland using P extraction and ignition procedures, fractionation and solution 31P nuclear magnetic resonance (NMR) spectroscopy. PFPs were identified by introducing the dye tracer Acid Blue 9 at the surface of a 1.25m2 study plot. The soil profile was vertically sliced and samples were collected from the unstained soil matrix and the dye-stained PFPs of each horizon of the podzol. Amorphous metal sesquioxides, naturally bound P (Pox), total P (Pt), inorganic P (Pin), organic P (Po), different inorganic P fractions (soluble P, Al-P, Fe-P, Ca-P, occluded P) and organic and inorganic P forms (31P-NMR spectroscopy) were analysed in the samples. The concentrations of different forms of P and amorphous metal sesquioxides varied between the different PFPs and the soil matrix within the podzol soil horizons. The PFPs in soils on stone surfaces contained less amorphous metal sesquioxides, Pox and Pt than the other flow regions. The PFPs related to coarse grains and roots contained equivalent or higher Pox and Pt concentrations than the soil matrix. Inorganic P was present as orthophosphates and pyrophosphates, and was mainly bound with Al and Ca oxides in PFPs, but also with Fe oxides in the soil matrix. PFPs contained more occluded P than the soil matrix, especially on stone surfaces. The results indicate increased mobilisation and P losses in PFPs on stone surfaces due to enhanced mineral weathering, root uptake and leaching of P adsorbed by the sesquioxides. The results of the 31P NMR study also showed higher proportions of pyrophosphate, orthophosphate diesters and monoesters other than phytic acid in the PFPs on stone surfaces than in the other flow regions, indicating higher amounts of labile forms of inorganic and organic P on stone surfaces than in other flow regions. To conclude, PFPs seem to have a twofold role in P dynamics: P can leach through PFPs on stone surfaces and accumulate on PFPs related to coarse grains and roots. Abstract Copyright (2012) Elsevier, B.V.
13045307 Ball, Becky A. (Dartmouth College, Environmental Studies Program, Hanover, NH) and Virginia, Ross A. Meltwater seep patches increase heterogeneity of soil geochemistry and therefore habitat suitability: Geoderma, 189-190, p. 652-660, illus. incl. 4 tables, sketch map, 69 ref., November 2012. Includes appendices.
The planet is undergoing an unequivocal period of climate change, with alterations in both longterm directional change and more local short-term variability. The amplified responses of polar ecosystems, and the potential feedbacks presented through alterations of soil processes, make it important to understand the consequences of climate change in polar soil systems. The McMurdo Dry Valleys of Antarctica have experienced periodic discrete warm climate events that result in melt water pulses from ice reserves, such as meltwater seep patches, alter geochemistry, and change habitat suitability for soil biotic communities and the ecological processes dictated by their activity. To investigate the consequences of soil seeps on soil geochemistry and biological activity, we sampled transects across six soil meltwater seep patches and measured soil water content, ion content, and potential CO2 flux to compare the seep habitat with the surrounding dry soil. We hypothesized that soils affected by meltwater seeps would be higher in salt content than the surrounding dry soils outside the seep patch. Though the increase in soil moisture in seeps could potentially increase biotic activity, we hypothesize that the osmotic stress resulting from a rise in soil salt concentration at the surface driven by evaporation would cause a decrease in biological activity. Our results show that seep patches increased soil moisture and salt content, particularly at the soil surface. The unaffected areas outside of seep patches differed widely in their ion content, typical of the high spatial geochemical heterogeneity found in the dry valleys. The presence of newly formed ice melt seeps can increase landscape-scale spatial heterogeneity by redistribution of soil salts from depth to the surface zone of the active layer. Seep patches have variable influence on biological activity, with both increases and decreases in respiration observed, related to the relative magnitudes of increases in moisture and salinity. Abstract Copyright (2012) Elsevier, B.V.
13045248 Bonilla, Carlos A. (Pontificia Universidad Católica de Chile, Departamento de Ingeniería Hidráulica y Ambiental, Santiago, Chile) and Johnson, Odette I. Soil erodibility mapping and its correlation with soil properties in central Chile: Geoderma, 189-190, p. 116-123, illus. incl. 5 tables, sketch maps, 36 ref., November 2012.
In the Revised Universal Soil Loss Equation (RUSLE), erodibility accounts for the influence of soil properties on soil loss during storm events in upland areas, which is represented by the soil erodibility factor (K). K-factor values are best obtained from long-term direct measurements on natural runoff plots; however, in the absence of field tests, these values can be estimated using relationships based on physical and chemical soil properties. Soil erosion by water is a major concern in Central Chile, and the application of many prediction technologies, such as the RUSLE, is limited due to the lack of information about erodibility factors. Because the direct measurement of K-factor values requires long-term erosion plot studies, the objective of this research was to use existing soil survey data to provide a first approximation of soil erodibility in the region and examine its relationship to soil properties in Central Chile. Erodibility values for a large variety of soil types and surface conditions (535 soil series) were calculated in this study, providing the first soil erodibility map for most of the country's cultivated land areas. Erodibility factors were calculated using two alternative relationships based on physical and chemical properties of surface soils. Results showed that the average K-factor value in the study area was 0.039±0.011 t ha h ha-1MJ-1mm-1, and 67% of soils had values between 0.03 and 0.05 t ha h ha-1MJ-1mm-1. The erodibility factors did not show a pattern with latitude or longitude mainly due to the lack of trends in the soil properties within the study area. Soil erodibility increased with silt content (r=0.607), and soil textures that contained predominantly silt as the primary particles were estimated to be the most vulnerable to water erosion. Organic matter content was not correlated to soil erodibility (r=0.086), and Mollisols and Entisols were the two only taxonomic orders that showed different erodibilities. The results of this study demonstrated the convenience of using silt content instead of clay, organic matter, or taxonomic order in preliminary classifications of water erosion vulnerability in Central Chile or areas with similar soil characteristics. Abstract Copyright (2012) Elsevier, B.V.
13045259 Egli, Markus (University of Zurich, Department of Geography, Zurich, Switzerland); Filip, Damien; Mavris, Christian; Fischer, Benjamin; Götze, Jens; Raimondi, Salvatore and Seibert, Jan. Rapid transformation of inorganic to organic and plant-available phosphorous in soils of a glacier forefield: Geoderma, 189-190, p. 215-226, illus. incl. 5 tables, sketch map, 62 ref., November 2012.
Chemical weathering of rocks or sediments is extremely important for the generation of soils, for the evolution of landscape, and as a main source of inorganic nutrients for plant growth and therefore for life. Temporal trends in weathering mechanisms, plant succession and nutrients availability in cold environments can be successfully studied in soil chronosequences along a glacier forefield. In the present paper, this was carried out in the pro-glacial area of Morteratsch. Different forms of phosphorous in the soil, stream and spring water chemistry were investigated. Apatite constitutes the main source of P, but it occurs only as a minor accessory mineral phase in the granitic/gneiss parent material. The identification of apatite was performed using SEM-EDX and cathodoluminescence. Water chemistry data indicated some calcite dissolution at the earliest phase of exposure, pyrite and - on older surfaces increasingly - feldspar weathering. Apatite also seemed to contribute to Ca which is leached from the soils. The concentrations of dissolved P in the stream and spring waters were, however, extremely low (only a few mg P/l). In the topsoil, the total stocks of P showed a slight decrease with time. Losses were rather difficult to detect even though the water fluxes through the soils and discharges are relatively high. Soil organic P is almost identical to the EDTA-extractable fraction. In an 11.5 ky-old soil outside the glacier forefield the concentration and proportions of organic P, EDTA-extractable P and inorganic P forms did not differ that much from the oldest soils (max. 150 years) of the glacier forefield. In the bulk soil, about 78% of total P was transformed into an organic form (40% already after 150 years) and, in the fine earth, about 81% (40-70% after about 150 years of soil evolution). Thus the P transformation reactions are shown to be very rapid, occur predominantly in the early phase of soil formation, and could be best described by an exponential decay model. Abstract Copyright (2012) Elsevier, B.V.
13045303 Karhu, Kristiina (Finnish Environment Institute, Natural Environment Centre, Helsinki, Finland); Gardenas, Annemieke I.; Heikkinen, Jaakko; Vanhala, Pekka; Tuomi, Mikko and Liski, Jari. Impacts of organic amendments on carbon stocks of an agricultural soil; comparison of model-simulations to measurements: Geoderma, 189-190, p. 606-616, illus. incl. 5 tables, 79 ref., November 2012.
Organic amendments such as straw, green manure or farmyard manure are used to mitigate the soil carbon (C) losses from cultivated soils. We investigated the role of various organic amendments with different C quality for development of soil C stocks, by simulating the Ultuna long-term soil organic matter experiment in Sweden with the Yasso07 model. The aim was to evaluate the performance of the Yasso07 soil carbon model in predicting changes in soil C stocks by comparing modeled C stocks to measurements between years 1956-1991. Uncertainty bounds were calculated from the estimated uncertainty in the C inputs and model parameters. The model performance was assessed in terms of regression coefficient (R2), root mean square error (RMSE) and model efficiency (ME). The model could very accurately predict the decrease in soil C stock in bare fallow, and in treatments receiving crop litter inputs and N fertilization. Yasso07 could also predict the increase in C stocks due to different organic matter applications, based on the varying quantity and quality of these C inputs. These results support the use of the model for testing the long-term effects of different agricultural measures aiming to mitigate soil C losses. Abstract Copyright (2012) Elsevier, B.V.
13045237 Martínez, Ingrid G. (Instituto de Investigaciones Agropecuarias, Chillan, Chile); Prat, Christian; Ovalle, Carlos; del Pozo, Alejandro; Stolpe, Neal and Zagal, Erick. Subsoiling improves conservation tillage in cereal production of severely degraded Alfisols under Mediterranean climate: Geoderma, 189-190, p. 10-17, illus. incl. 4 tables, 54 ref., November 2012.
Central Chile has a Mediterranean climate with a mean annual precipitation of 695mm, 80% concentrated in winter. In this context, water erosion and inappropriate agricultural management along hillslopes are the major causes of soil degradation. From 2007 to 2010, different agricultural systems were compared: conservation tillage with stubble retained: no tillage (Nt), Nt+subsoiling (Nt+Sb), Nt+barrier hedges (Nt+Bh) and Nt+contour plowing (Nt+Cp). All the systems were compared to conventional tillage (Ct) without crop stubble on the surface. The runoff plots were 50m´20m on a hillside with 12.5% slope in an oat-wheat crop rotation. Runoff, sediment and nutrient losses measured for every rainfall event, occurred during winter months when rainfall energy was also the highest of the whole year. Conservation tillage systems mitigate water erosion compared to the Ct system. In heavy rains, conservation tillage systems reduced soil loss by more than 72% compared to Ct. In addition, the runoff coefficient during the rainy period was 70% lower in conservation tillage systems when the crop was at the initial tillering stage and 90% lower at final tillering. These results show the importance of conservation tillage and crop stubble to decrease erosion, especially in years when extreme precipitation presented a high potential for soil erosion. Moreover, cereal production showed higher biomass and grain yield in Nt+Sb. It was concluded that no tillage with stubble retained on the surface was the best option to mitigate soil erosion. However, the effects of subsoiling decrease over time, making new subsoiling necessary with the implied costs. Due to the strong fluctuations in the prices of the agricultural products, it is impossible to estimate the balance of costs/benefits of this system. On other hand, the duration of the experiment may have been too short to measure the real impacts of no-tillage practices. Abstract Copyright (2012) Elsevier, B.V.
13045289 Pare, Maxime C. (University of Saskatchewan, Department of Soil Science, Saskatoon, SK, Canada) and Bedard-Haughn, Angela. Landscape-scale N mineralization and greenhouse gas emissions in Canadian Cryosols: Geoderma, 189-190, p. 469-479, illus. incl. 3 tables, 92 ref., November 2012.
Arctic soils store great amounts of soil organic matter (SOM) that are likely to be affected by future climate changes. Knowledge of the ability of the soil to mineralize nitrogen (N) and release greenhouse gases (GHG) at the landscape scale is critical to predict and model future effects of climate change on Arctic SOM. The objective of this study was to investigate how soil gross N mineralization and GHG emissions vary across landscapes and Arctic ecosystems. This study was conducted in three Arctic ecosystems: Sub-Arctic (Churchill, MB), Low-Arctic (Daring Lake, NWT), and High-Arctic (Truelove Lowlands, NU). The topography was divided into five landform units: 1) upper (Up), 2) back (Back), and 3) lower (Low) slopes for catena sites and 4) hummock and 5) interhummock for hummocky sites (i.e., hummock in Churchill and ice-wedge polygons in Truelove). All sites were sampled near the end of their growing seasons (i.e., from two to three weeks before plant senescence). Soil gross N mineralization was measured in situ using a 15N dilution technique, whereas soil GHG emissions (N2O, CH4, and CO2) were measured in situ using a multicomponent Fourier transform infrared gas analyzer combined with an automated dark chamber. For all ecosystems, topography significantly influenced soil gross N mineralization and CO2 emissions. Topography had no significant impact on N2O and CH4 fluxes most likely because net fluxes were extremely low throughout landscapes. Soil gross N mineralization and CO2 emissions increased from Up, Back, to Low and from hummock to interhummock landform units. For example, at Churchill, soil gross mineralization rates averaged 4 mg N-NH4+ kg-1d-1 in upper slopes and progressively increased to about 25 mg N-NH4+ kg-1d-1 in the lower slopes. Similarly, CO2 emission rates at Daring Lake averaged 0.5mmol CO2 m-2s-1 in upper slopes and progressively increased to about 2.3mmol CO2m-2s-1 in the lower slopes. Comparisons among ecosystems showed that Churchill (Sub-Arctic) had the highest gross N mineralization rates followed by Truelove (High-Arctic) and Daring Lake (Low-Arctic). Furthermore, Daring Lake had significantly higher CO2 emissions than Churchill and no difference in CH4 and N2O emissions between both ecosystems was found. These findings suggest that all factors influencing C and N cycling processes such as climate and human induced changes may not have similar effects across landscapes or across Arctic ecosystems. Abstract Copyright (2012) Elsevier, B.V.
13045272 Sun, Y. (China Agricultural University, College of Information and Electrical Engineering, Beijing, China); Cheng, Q.; Xue, X.; Fu, L.; Chai, J.; Meng, F.; Schulze Lammers, P. and Jones, S. B. Determining in-situ soil freeze-thaw cycle dynamics using an access tube-based dielectric sensor: Geoderma, 189-190, p. 321-327, illus. incl. 1 table, 36 ref., November 2012.
Dielectric sensors have been widely used for determining soil water content, but until now few have been effectively applied for observing the freeze-thaw cycle in soil at the field scale. With this intention we tested a frequency domain (FD) probe designed for use in access tubes installed into the ground at five sites. For accurate depth-referenced measurements, a series of magnetism-sensing Hall-switches was used. The experiment was carried out over the winter of 2009-2010. The temperature-dependent dielectric response was interpreted using a mixing model to fit four soil components, solid, air, liquid water and ice. To illustrate the soil frost dynamics over time, the measured liquid water content of frozen soil (LWCFS) was transformed into different expressions including frozen soil profile, frost penetration map, freezing front trace and thawing front trace. In contrast to Time Domain Reflectometry (TDR) instruments, the proposed technique is easy to operate, reasonably accurate, non-destructive, and has a rapid soil profiling output. In addition, there is a significant cost advantage using a single profiling probe across multiple sites. Abstract Copyright (2012) Elsevier, B.V.
13045266 Weindorf, David C. (Louisiana State University Agricultural Center, Baton Rouge, LA); Zhu, Yuanda; McDaniel, Paul; Valerio, Mitchell; Lynn, Lorene; Michaelson, Gary; Clark, Mark and Ping, Chien Lu. Characterizing soils via portable X-ray fluorescence spectrometer; 2, Spodic and albic horizons: Geoderma, 189-190, p. 268-277, illus. incl. 2 tables, sketch map, 39 ref., November 2012.
Differentiation of horizons in soils formed in volcanic ash can be problematic as recent ash deposits often have the same morphological appearance as eluvial albic horizons. Furthermore, differentiation of spodic horizons can be difficult as multiple horizons can appear homogeneous. A portable x-ray fluorescence (PXRF) spectrometer was utilized to scan volcanic ash-derived Spodosols, Andisols, and Inceptisols in northern Idaho and southern Alaska. Distinct patterns of elemental concentrations were identified in soil profiles. These data can be used to quantitatively differentiate seemingly nondescript horizons. Organic carbon variability within soil profiles was found to significantly correlate to elemental concentrations as evidenced by strong regression r2 and low root mean squared errors (RMSEs). Specifically, Fe/Zr ratios proved useful for documenting spodic horizons in the studied profiles, and showed some potential for differentiating volcanic ash from true E horizons. In areas of frequent saturation or inundation, the PXRF also demonstrated the ability to distinguish depleted soil matrix materials from reduced Fe. Summarily, the PXRF proved to be a useful instrument for rapid, on-site analysis of volcanic ash soils. Abstract Copyright (2012) Elsevier, B.V.
13048526 Lopatin, D. V. (Sankt-Peterburgskiy Gosudarstvennyy Universitet, Saint Petersburg, Russian Federation) and Shavel', N. I. Osobennosti ekzodinamicheskogo morfolitogeneza Orlovsko-Spokoynenskogo redkometal'nogo rudnogo polya (Yugo-Vostochnoye Zabaykal'ye) [Peculiarities of exodynamic morpholithogenesis of the Orlov-Spokoynenskoye rare metal ore deposit (southeastern Transbaikalia)]: Geomorfologiya, 2012(1), p. 72-81 (English sum.), sketch maps, 7 ref., March 2012.
Structural-geomorphologic indicators of the covered stocks in poorly exposed areas are very important for rare-metal ore-bearing stocks prospecting. Orlovsko-Spokoynenkiy ore field in the northern sector of the outer zone of the Aginskaya late Mesozoic macro-structural form with a central-type symmetry was taken as a test site. At the first stage, an investigation of exogenic processes was fulfilled. Creep, sheet wash and linear erosion are the main processes in the area, especially intense during heavy rains. Frost processes like solifluction and congelifluction are of some importance too.
13046620 Shiklomanov, Nikolay I. (George Washington University, Department of Geography, Washington, DC). Non-climatic factors and long-term, continental-scale changes in seasonally frozen ground: Environmental Research Letters, 7(1), Citation 011003, 11 ref., March 2012.
13051050 Groffman, Peter M. (Cary Institute of Ecosystem Studies, Millbrook, NY); Hardy, Janet P.; Fashu-Kanu, Samuel; Driscoll, Charles T.; Cleavitt, Natalie L.; Fahey, Timothy J. and Fisk, Melany C. Snow depth, soil freezing and nitrogen cycling in a northern hardwood forest landscape: Biogeochemistry (Dordrecht), 102(1-3), p. 223-238, illus. incl. 5 tables, 65 ref., January 2011.
Increases in soil freezing associated with decreases in snow cover have been identified as a significant disturbance to nitrogen (N) cycling in northern hardwood forests. We created a range of soil freezing intensity through snow manipulation experiments along an elevation gradient at the Hubbard Brook Experimental Forest (HBEF) in the White Mountains, NH USA in order to improve understanding of the factors regulating freeze effects on nitrate (NO3-) leaching, nitrous oxide (N2O) flux, potential and in situ net N mineralization and nitrification, microbial biomass carbon (C) and N content and respiration, and denitrification. While the snow manipulation treatment produced deep and persistent soil freezing at all sites, effects on hydrologic and gaseous losses of N were less than expected and less than values observed in previous studies at the HBEF. There was no relationship between frost depth, frost heaving and NO3 - leaching, and a weak relationship between frost depth and winter N2O flux. There was a significant positive relationship between dissolved organic carbon (DOC) and NO3 - concentrations in treatment plots but not in reference plots, suggesting that the snow manipulation treatment mobilized available C, which may have stimulated retention of N and prevented treatment effects on N losses. While the results support the hypothesis that climate change resulting in less snow and more soil freezing will increase N losses from northern hardwood forests, they also suggest that ecosystem response to soil freezing disturbance is affected by multiple factors that must be reconciled in future research. Copyright 2010 Springer Science+Business Media B.V.
13051051 Narhi, Paavo (Geological Survey of Finland, Rovaniemi, Finland); Middleton, Maarit; Gustavsson, Nils; Hyvonen, Eija; Sutinen, Marja-Liisa and Sutinen, Raimo. Importance of soil calcium for composition of understory vegetation in boreal forests of Finnish Lapland: Biogeochemistry (Dordrecht), 102(1-3), p. 239-249, illus. incl. 3 tables, sketch map, 64 ref., January 2011.
To focus conservation efforts into forest areas with high biodiversity, more information is needed about soil-vegetation dependencies in Finnish Lapland. We studied understory vegetation and soil variables along a transect across a felsic-mafic lithological sequence in central Finnish Lapland. At 119 northern boreal forest sites, coverages of understory vegetation, several mineral soil chemical elements, soil electrical conductivity, pH, and dielectric permittivity, as a measure of soil volumetric water content, were measured. We found that soil Ca concentration and Ca:Al ratio were the main variables determining vegetation composition and diversity. Ca-rich soils were characterised by high electrical conductivity, pH, and Mg concentration, and by low concentration of Al, S, Zn, and low C:N ratio. Soil Ca concentration is a diagnostic measure of plant diversity as concentration higher than 100 mg kg-1 resulted in a considerable increase in plant diversity. Sites with Ca concentration this high were rare, and probably important in maintaining high biodiversity. The median soil Ca:Al ratio was only 0.02, suggesting, according to general theory, a considerable risk for aluminium stress. We found Geranium sylvaticum and Rubus saxatilis to be good indicators for Ca-rich regimes and high plant diversity. Copyright 2010 Springer Science+Business Media B.V.
13046602 Frauenfeld, Oliver W. (Texas A&M University, Department of Geography, College Station, TX) and Zhang, Tingjun. An observational 71-year history of seasonally frozen ground changes in the Eurasian high latitudes: Environmental Research Letters, 6(4), Citation 044024, illus. incl. sketch map, 23 ref., 2011.
In recent decades, significant changes have occurred in high-latitude areas, particularly to the cryosphere. Sea ice extent and thickness have declined. In land areas, glaciers and ice sheets are experiencing negative mass balance changes, and there is substantial regional snow cover variability. Subsurface changes are also occurring in northern soils. This study focuses on these changes in the soil thermal regime, specifically the seasonally frozen ground region of Eurasia. We use a database of soil temperatures at 423 stations and estimate the maximum annual soil freezing depth at the 387 sites located on seasonally frozen ground. Evaluating seasonal freeze depth at these sites for 1930-2000 reveals a statistically significant trend of -4.5 cm/decade and a net change of -31.9 cm. Interdecadal variability is also evident such that there was no trend until the late 1960s, after which seasonal freeze depths decreased significantly until the early 1990s. From that point forward, likely through at least 2008, no change is evident. These changes in the soil thermal regime are most closely linked with the freezing index, but also mean annual air temperatures and snow depth. Antecedent conditions from the previous warm season do not appear to play a large role in affecting the subsequent cold season's seasonal freeze depths. The strong decrease in seasonal freeze depths during the 1970s to 1990s was likely the result of strong atmospheric forcing from the North Atlantic Oscillation during that time period. Copyright 2011 IOP Publishing Ltd
13050789 Kashulina, Galina M. (Russian Academy of Sciences, Polar Alpine Botanical Garden-Institute, Apatity, Russian Federation); Pereverzev, V. N. and Litvinova, T. I. Transformation of the soil organic matter under the extreme pollution by emissions of the Severonikel smelter: Eurasian Soil Science, 43(10), p. 1174-1183, illus., 15 ref., October 2010. Based on Publisher-supplied data.
The direct impact of the long-term extreme pollution by emissions of the Severonikel copper-nickel processing plant per se is not capable of inhibiting the organic matter transformation even within the local zone of this enterprise. However, a great number of indirect pollution factors can affect the organic matter content and the composition of the soils in the local zone. The destruction of the vegetation and the changes in the amount and botanical composition of the falloff influence the soil humus status to the greatest extent. As fresh falloff is absent, the old (formerly accumulated) organic matter of the soils is gradually mineralized, and its content decreases. In the most damaged ecosystems of the local zone, the soils have lost almost all their organic matter, and their properties are returning to those of the initial parent rock. The disturbance of the water regime of some ecosystems and of the whole landscape intensifies the migration of substances within the soil profiles and in the whole landscape. This is the second by significance factor affecting the humus status of the soils in the local zone. The transformation of the organic soil profiles under the influence of the indirect factors is sufficient to change their taxonomic position at the level of subtypes or type. Copyright 2010 Pleiades Publishing, Ltd.
13050800 Fan, Ying (Rutgers University, Department of Earth & Planetary Sciences, New Brunswick, NJ) and Miguez-Macho, G. Potential groundwater contribution to Amazon evapotranspiration: Hydrology and Earth System Sciences (HESS), 14(10), p. 2039-2056, illus. incl. 4 tables, sketch maps, 74 ref., 2010. Includes supplement, URL: http://www.hydrol-earth-syst-sci.net/14/2039/2010/hess-14-2039-2010-supp lement.pdf; published in Hydrology and Earth System Sciences Discussion: 30 July 2010, URL: http://www.hydrol-earth-syst-sci-discuss.net/7/5131/2010/hessd-7-5131-2010 .html; accessed in Aug., 2012.
Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations do not support these results, indicating adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution), both absent in the models. Here we provide a first-order assessment of the potential importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of equilibrium water table depth from available observations and a groundwater model simulation constrained by these observations. We then present a map of maximum capillary flux these water table depths, combined with the fine-textured soils in the Amazon, can potentially support. The maps show that the water table beneath the Amazon can be shallow in lowlands and river valleys (<5 m in 36% and <10 m in 60% of Amazonia). These water table depths can potentially accommodate a maximum capillary flux of 2.1 mm day-1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day-1 across nine study sites. We note that the results presented here are based on limited observations and simple equilibrium model calculations, and as such, have important limitations and must be interpreted accordingly. The potential capillary fluxes are not indicative of their contribution to the actual evapotranspiration, and they are only an assessment of the possible rate at which this flux can occur, to illustrate the power of soil capillary force acting on a shallow water table in fine textured soils. They may over-estimate the actual flux where the surface soils remain moist. Their contribution to the actual evapotranspiration can only be assessed through fully coupled model simulation of the dynamic feedbacks between soil water and groundwater with sub-daily climate forcing. The equilibrium water table obtained here serves as the initial state for the dynamic simulation, and together with the equilibrium potential capillary flux, will serve as a baseline to evaluate the diurnal, event, seasonal and inter-annual dynamics.
13044626 Guan, Xiu Juan (University of Saskatchewan, Department of Geography & Planning, Saskatoon, SK, Canada); Spence, Chris and Westbrook, Cherie J. Shallow soil moisture-ground thaw interactions and controls; Part 2, Influences of water and energy fluxes: Hydrology and Earth System Sciences (HESS), 14(7), p. 1387-1400, illus. incl. 1 table, sketch map, 60 ref., 2010. Includes appendix; part of special issue no. 105, Cold region hydrology: improved processes, parameterization and prediction, edited by Carey, S., et al., URL: http://www.hydrol-earth-syst-sci.net/special_issue105.html; published in Hydrology and Earth System Sciences Discussion: 8 January 2010, URL: http://www.hydrol-earth-syst-sci-discuss.net/7/67/2010/hessd-7-67-2010.h tml; accessed in Apr., 2012.
The companion paper (Guan et al., 2010) demonstrated variable interactions and correlations between shallow soil moisture and ground thaw in soil filled areas along a wetness spectrum in a subarctic Canadian Precambrian Shield landscape. From wetter to drier, these included a wetland, peatland and soil filled valley. Herein, water and energy fluxes were examined for these same subarctic study sites to discern the key controlling processes on the found patterns. Results showed the presence of surface water was the key control in variable soil moisture and frost table interactions among sites. At the peatland and wetland sites, accumulated water in depressions and flow paths maintained soil moisture for a longer duration than at the hummock tops. These wet areas were often locations of deepest thaw depth due to the transfer of latent heat accompanying lateral surface runoff. Although the peatland and wetland sites had large inundation extent, modified Peclet numbers indicated the relative influence of external and internal hydrological and energy processes at each site were different. Continuous inflow from an upstream lake into the wetland site caused advective and conductive thermal energies to be of equal importance to ground thaw. The absence of continuous surface flow at the peatland and valley sites led to dominance of conductive thermal energy over advective energy for ground thaw. The results suggest that the modified Peclet number could be a very useful parameter to differentiate landscape components in modeling frost table heterogeneity. The calculated water and energy fluxes, and the modified Peclet number provide quantitative explanations for the shallow soil moisture-ground thaw patterns by linking them with hydrological processes and hillslope storage capacity.
13044625 Guan, Xiu Juan (University of Saskatchewan, Centre for Hydrology, Department of Geography & Planning, Saskatoon, SK, Canada); Westbrook, Cherie J. and Spence, Chris. Shallow soil moisture-ground thaw interactions and controls; Part 1, Spatiotemporal patterns and correlations over a subarctic landscape: Hydrology and Earth System Sciences (HESS), 14(7), p. 1375-1386, illus. incl. 1 table, sketch maps, 41 ref., 2010. Part of special issue no. 105, Cold region hydrology: improved processes, parameterization and prediction, edited by Carey, S., et al., URL: http://www.hydrol-earth-syst-sci.net/special_issue105.html; ublished in Hydrology and Earth System Sciences Discussion: 8 January 2010, URL: http://www.hydrol-earth-syst-sci-discuss.net/7/33/2010/hessd-7-33-2010.h tml; accessed in Apr., 2012.
Soil moisture and ground thaw state are both indicative of a hillslope's ability to transfer water. In cold regions, in particular, it is widely known that the depth of the active layer and wetness of surface soils are important for runoff generation, but the diversity of interactions between ground thaw and surface soil moisture themselves has not been studied. To fill this knowledge gap, detailed shallow soil moisture and thaw depth surveys were conducted along systematic grids at the Baker Creek Basin, Northwest Territories. Multiple hillslopes were studied to determine how the interactions differed along a spectrum of topological, typological and topographic situations across the landscape. Overall results did not show a simple link between soil moisture and ground thaw as was expected. Instead, correlation was a function of wetness. The interaction between soil moisture and ground thaw was more dependent at wetter sites. This indicates that interactive soil moisture and thaw depth behaviour on hillslopes in cold regions changes with location and cannot necessarily be lumped together in hydrological models. To explore further why these differences arise, a companion paper (Guan et al., 2010) will examine how the hydrological and energy fluxes influenced the patterns of moisture and thaw among the study sites.
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13051424 Khromova, T. E. (Russian Academy of Sciences, Institute of Geography, Moscow, Russian Federation). Cryosphere and climate: in International conference on Planetary boundary layer and climate change (Djolov, G., editor; et al.), IOP Conference Series. Earth and Environmental Science, 13(1), paper 012002, illus. incl. sketch maps, 9 ref., 2010. Meeting: International conference on Planetary boundary layer and climate change, Oct. 26-28, 2009, Cape Town, South Africa.
Analysis of current and historical data demonstrates that the cryosphere component are very sensitive to the climate change thus proving its role as the climate indicator. In the process of this a pattern of the changes clearly reflect regional climate characteristics. International cryospheric community works very hard for efficient organization of observations of the cryosphere components and specific features of its development against background of changing climate. Geophysical, geochemical, space and other methods are used for solution of this problem. Copyright (Copyright) 2010 IOP Publishing Ltd
13051510 Anand, Ravi R. (Commonwealth Scientific and Industrial Research Organization, Exploration and Mining, Kensington, West. Aust., Australia). Mechanisms of metal transport through transported cover; implications to mineral exploration [abstr.]: in 34th international geological congress; abstracts, International Geological Congress, Abstracts = Congrès Géologique International, Résumés, 34, p. 2641, 2012. compact disc. Meeting: 34th international geological congress, Aug. 5-10, 2012, Brisbane, Queensl., Australia.
As mineral exploration moves into regions dominated by transported cover, conventional techniques are simply not applicable and thus increasingly there is a need for new innovative approaches to geochemical exploration. But to develop such new approaches there is a major need to identify the operating mechanisms capable of transferring metals from buried mineralisation upwards through cover to the surface. This paper presents a synthesis of the experimental and field trials conducted in Australia and Chile as part of an industry-supported three year CSIRO/AMIRA Project 778. Three mechanisms of vertical metal migration are important from source to the surface in vadose environments; biological, gaseous and to some extent capillary mechanisms. Upward element transfer by vegetation (Acacia aneura and Eucalyptus spp.) occurs in areas of transported overburden up to 35 m thick, but not in environments which lack supergene enrichment and have highly saline groundwater. Microbial populations show an anomalous bacterial community type in the soil over the mineralisation. Similarly, volatile metals and hydrocarbons, detected by gas collectors, are transferred to surface as gases. Experimental trials have demonstrated processes of metal transport and has shown that geochemical anomalies can form rapidly. Seasonal variations suggest the migration of elements from source to the surface may vary in time and in intensity. This research is ongoing as part of the CSIRO/AMIRA Project 778A.
13044751 Coronato, Andrea (Consejo Nacional de Investigaciones Científicas y Técnicas, Centro Austral de Investigaciones Científicas, Ushuaia, Argentina); Fanning, Patricia; Salemme, Mónica; Oría, Jimena; Pickard, John and Ponce, Juan Federico. Aeolian sequence and the archaeological record in the Fuegian steppe, Argentina: in Multidisciplinary studies in southern South American archaeology (Bonomo, Mariano, editor; et al.), Quaternary International, 245(1), p. 122-135, illus. incl. strat. col., 9 tables, geol. sketch maps, 72 ref., November 29, 2011. Meeting: IV congreso argentino de cuaternario y geomorfología, XII congresso da Assoçiacão Brasileira de Estudos do Quaternário, and II reunión sobre el Cuaternario de América del Sur; symposium on Multidisciplinary studies in archaeology, Sept. 2009, La Plata, Argentina.
A 20 m thick sequence of aeolian deposits and palaeosols, deposited above Neogene marine sediments adjacent to the shallow saline ephemeral Lake Arturo in interior Tierra del Fuego, is described. A deposit of archaeological stone artifacts and bones, the Lake Arturo 1 archaeological site, is located in a deflation hollow near the top of the aeolian sequence. The sequence of nine aeolian deposits, including eight palaeosols and capped by the contemporary soil, provides evidence of environmental changes which have occurred during the Holocene in the cold Fuegian steppe, beginning as early as the Late Glacial-Early Holocene transition. A chronostratigraphy is provided by guanaco (Lama guanicoe) and Canidae bones embedded within palaeosols and organic matter content, radiocarbon dated from 9951±59 BP (11,304 cal. BP) at the base of the sequence to 434±43 BP (471 cal. BP) near the top. A tephra layer between Palaeosols 4 and 5 is interpreted from its geochemical fingerprint as the product of one of the mid-Holocene eruptions of Mt. Burney, located in the Southern Patagonian Andes. It is suggested that the accumulation of the aeolian sediments occurred throughout most of the Holocene, as a result of both local acquisition of fine particles derived from the weathering and erosion of the basal Neogene marine sediments, and deflation from the intermittently dry lake bed, as well as deposition of material transported by wind from more distant sources. The orientation of the aeolian deposits suggests a more northwesterly wind direction instead of the present westerlies. Weakly developed A horizons capping each of the sediment units suggest that the landscape was sensitive to environmental change, from more arid conditions when the aeolian deposits accumulated to brief periods of landscape stability when topsoil development occurred. Evidence of human occupation in Lake Arturo 1 is confined to the upper part of the sequence (ca. 500 years BP) and is interpreted as a place for primary butchering and raw material acquisition.
13045004 Burns, Patrick J. (Oregon State University, Department of Geosciences, Corvallis, OR) and Nolin, Anne W. Assessment of a distributed hydrological model applied to a glacierized basin in the Cordillera Blanca, Peru [abstr.]: in Geological Society of America, 2011 annual meeting, Abstracts with Programs - Geological Society of America, 43(5), p. 577, October 2011. Meeting: Geological Society of America, 2011 annual meeting, Oct. 9-12, 2011, Minneapolis, MN.
Glacier retreat may have substantial impacts on water resources for heavily populated regions, such as the Peruvian Andes. Water vulnerability is high in this region prompting a need for better predictions of glacier contributions to streamflow. This study in the Llanganuco Basin, Peru, seeks to determine how well the Distributed Hydrology Soil Vegetation Model (DHSVM) with a newly integrated glacier component predicts dry season contributions of glacier meltwater to streamflow. Field data for calibration and validation were collected during the 2011 dry season. We installed two stage height recorders, collected water samples for use in an isotopic mixing model, and also acquired meteorological information needed to run the model. We also mapped major soil types and defined vegetation classes in the basin. The three main objectives of this ongoing effort are to: (1) map glacier extent and its changes over the past 25 years; (2) determine the fraction of stream discharge derived from glacier melt in the basin; and (3) assess the accuracy of modeled stream discharge during the low flow season. Estimated contributions of glacier meltwater, coupled with discharge measurements, will provide an important first order check on the model. This study will be a valuable step in a complete model validation, providing important diagnostic information for incremental improvements to a model, which will eventually be used for similar glacierized basins in the Canadian Rocky Mountains and Himalaya.
13051370 Creason, C. Gabe (University of Kansas, Department of Geology, Lawrence, KS); Hekman, Marjorie S.; Vallotto, Marco; Halfen, Alan F. and Johnson, William C. Valley-fill architecture and alluvial landforms within the upper Kansas River; an undergraduate USGS EDMAP experience [abstr.]: in Geological Society of America, 2011 annual meeting, Abstracts with Programs - Geological Society of America, 43(5), p. 628, October 2011. Meeting: Geological Society of America, 2011 annual meeting, Oct. 9-12, 2011, Minneapolis, MN.
Kansas River is unique among other Great Plains fluvial systems because it lies entirely within the Great Plains. This presentation, a continuation of research presented on the lower Kansas River drainage basin (LKR) last year, investigates the upper Kansas River drainage basin (UKR) to map the alluvial architecture and to document the chronological development of the river valley. Remotely-sensed data (e.g., LiDAR, NAIP), other databases (e.g., SSURGO, well logs), and field investigations were used to map river terraces within a 40-km reach of the UKR. Four terraces previously mapped in the LKR were also mapped in this reach: the Menoken, Buck Creek, Newman, and Holliday. Sample sites were established on each terrace, and stratigraphy was ascertained through exposures, hand auguring and hydraulic coring. Numerical age data were derived from OSL and 14C samples collected at select sites. As in the LKR, the Menoken contains glaciofluvial sediments that thicken in proximity to the river--this deposit has been ascribed to the Kansan Glaciation (600-700 ka). In the LKR, the Menoken is overlain by Pleistocene dunes (31-36 ka), however, due to the limited expression of the Menoken in the UKR, these same dune deposits are found mantling bedrock. Eolian dunes were also mapped at the headwaters of the UKR, but these are believed to be much younger. The most widely mapped terrace in the UKR is the Buck Creek, a thick, fine-grain deposit that has been previously dated at ~15 ka. Investigations into the Buck Creek in tributaries indicate that the terrace fill may have a lower sandy unit thus far undocumented within the main river valley. The Newman is extensive on the south side of the river valley and consists of a variably thick basal soil that formed between 10-14 ka and overlying Holocene alluvium with intercalated paleosols. The Holliday is late Holocene in age (<4 ka), and consists of primarily abandoned meander scrolls and active channels. Data from this project, combined with the results collected from the LKR, were integrated into GIS and used to produce various databases and maps including a 3D river valley bedrock map extrapolated from LiDAR and water and oil well logs. These data provide a perspective on the recent geologic history of the region, which enhances our understanding of river response to climate change in the Great Plains.
13051362 Miao, Xiaodong (University of Illinois, Prairie Research Institute, Champaign, IL); Thomason, Jason F.; Brown, Steven E. and Stohr, Christopher. Updated sand and gravel resources of McHenry County, Illinois [abstr.]: in Geological Society of America, 2011 annual meeting, Abstracts with Programs - Geological Society of America, 43(5), p. 627, October 2011. Meeting: Geological Society of America, 2011 annual meeting, Oct. 9-12, 2011, Minneapolis, MN.
McHenry County, in northeastern Illinois, contains extensive deposits of sand and gravel, which were deposited mostly by glacial meltwater streams of the recent geological past. The geological origins and landforms associated with these deposits were classified and their occurrences have been described. However, the thickness and depth of burial of these deposits, two of the important factors for the aggregate industry, are not documented well. Fortunately, surficial mapping and 3D mapping by the ISGS and state universities at a variety of scales have provided important new data in the last two decades. Potential sand and gravel resources are presented in two ways. First, stratigraphic drilling sites are shown and labeled with 4 numbers related to the sand and gravel layers at the site. The labels indicate total thickness of sand and gravel, number of layers, maximum thickness. and depth of burial of the single thickest layer. In addition, we reclassify McHenry County map of NRCS Soil Survey Geographic (SSURGO) Database: the lowermost soil texture. For example, "warm" colors such as red, tan, and yellow represent relatively coarse-grained materials such as gravel, sand and gravel, and sand, respectively. Alternatively, units symbolized with "cool" colors such as blue and green represent relatively fine-grained materials such as clay and clay loam. This representation of soil texture data coupled with detailed stratigraphic drilling data shows a more detailed distribution of possible aggregate-grade sand and gravel deposits than previous studies. Good agreement between shallow soil texture and the deep borehole sand and gravel thickness gives confidence on the attempts to use soil data to assess sand and gravel resources. Thus, the methodology used in our study can be applied to other counties in Illinois and elsewhere. As the Chicago metropolitan area population continues to grow, a better understanding of the distribution of sand and gravel deposits in McHenry County and nearby counties will be increasingly important for land use, environmental planning, and ground water resource decisions. In addition, this type of map can certainly help constituents in the sand and gravel industry with implications for aggregate quality, transportation and economic feasibility.
13049131 Murphy, Laura R. (Kansas Geological Survey, Lawrence, KS); Ludvigson, Greg; Joeckel, R. M. and Gonzalez, L. A. Early Cretaceous baseline atmospheric pCO2 and buildup estimated from a calcrete succession, Cedar Mountain Formation, Utah, USA [abstr.]: in Geological Society of America, 2011 annual meeting, Abstracts with Programs - Geological Society of America, 43(5), p. 617, October 2011. Meeting: Geological Society of America, 2011 annual meeting, Oct. 9-12, 2011, Minneapolis, MN.
We calculate a baseline Aptian-Albian atmospheric rCO2 of 1,000 ppm by applying the equation of Ekart et al. (1999, AJS 299:805-827) to isotopic analyses of pedogenic and palustrine carbonates from eight correlated chemostratigraphic positions. The positions are from the Ap7 C-isotope feature of Herrle et al. (2004, EPSL 218:149-161) to the C15 C-isotope feature of Bralower et al. (1999, JFR 29:418-437) at two sections in the Cedar Mountain Formation (Ruby Ranch Road and Muddy Creek, eastern Utah). These sections encompass the Aptian-Albian Ap7-C15 (~125-100 Ma) interval (Ludvigson et al., 2010, JSR 80:955-974). Significantly, our results indicate a buildup in atmospheric rCO2 of ~350 ppm above baseline values during the C9-C11 positive carbon isotope excursion. Furthermore, this excursion corresponds with our reported shifts in d13C values determined from coordinated carbonate and sedimentary organic carbon. We realize that S(z), the soil-derived component of total soil CO2 at depth z, significantly varies with season, depth, soil type, and paleolatitude. Thus, unlike other studies that use a constant S(z), we report a range of rCO2 values using several S(z) estimates. Direct comparison of our rCO2 measurements to compiled estimates from the same interval determined on pedogenic carbonates, stomata, and liverworts recently published (Royer, 2010, PNAS 107:517-518) emphasizes the need for a non-uniform S(z) approach. Finally, we correlate our rCO2 with high-resolution marine chemostratigraphic records (d13C(carb), d13C(org), 87Sr/86Sr), and magma flux output from the Kergulean Plateau (Indian Ocean). The 116 to 111 Ma rise and fall in rCO2 during the C9-C11 carbon isotope excursion, for which we have identified a rCO2 buildup, coincides with the well-documented Mid-Cretaceous strontium isotope low, and with a peak in magma production at the Kerguelan Large Igneous Province. Therefore, we interpret a tectonic driver for this global change event.
13048980 Poage, Michael A. (Indiana University of Pennsylvania, Geoscience Department, Indiana, PA); Virginia, Ross A. and Johnson, Kelsey G. Relationships between soil geochemistry and nematode habitat suitability, Taylor Valley, Antarctica [abstr.]: in Geological Society of America, 2011 annual meeting, Abstracts with Programs - Geological Society of America, 43(5), p. 590, October 2011. Meeting: Geological Society of America, 2011 annual meeting, Oct. 9-12, 2011, Minneapolis, MN.
Due to the limited influence of surface hydrology, desert environments often preserve spatial variation in soil chemistry that can be linked to landscape history and influence extant ecosystems. Soils in the McMurdo Dry Valleys of Antarctica are among the coldest and driest terrestrial environments. Despite extreme conditions, dry valley soils host low-diversity food webs of microbes, protozoa, and metazoan invertebrates. In most dry valley soils where metazoans are present, communities are composed of a single species, the endemic nematode, Scottnema lindsayae, with additional species occurring less frequently depending upon soil conditions. Much research has focused on moisture and temperature as limitations to geochemical cycling and biological activity, however recent work has demonstrated that soil geochemistry can strongly influence the distribution and functioning of biological communities in the dry valleys. For example, Poage et al. (2008) compiled Dry Valleys-wide nematode occurrence and geochemical data and established soil conductivity and to a lesser degree soil moisture and total soil nitrogen as statistically significant predictors of live S. lindsayae occurrence. Previous work from sampling transects in the Lake Fryxell, Lake Hoare and Lake Bonney Basins in Taylor Valley documented orders of magnitude variation in soil geochemistry on multiple spatial scales. Here we present soil conductivity, moisture, and total nitrogen data from a hectare plot in the Lake Fryxell Basin and show that, at lower elevations, soil chemistry can vary over orders of magnitude on the multi-meter spatial scale, structuring a complex mosaic of favorable and unfavorable nematode habitats. The geochemistry of dry valley soils is fundamentally linked to each valley's complex history, integrating the effects of climate, soil hydrology, glacial activity, lake inundation and recession, atmospheric deposition, and surface age. A strong correlation between soil geochemistry and soil texture suggests a direct linkage between deposition of variably textured sediments deposited during higher lake stands and soil salinity, which strongly influences distribution of nematode communities.
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