WorldWideScience

Sample records for transitory permafrost conditions

  1. Surface and subsurface conditions in permafrost areas - a literature review

    International Nuclear Information System (INIS)

    Vidstrand, Patrik

    2003-02-01

    This report contains a summary of some of the information within existing technical and scientific literature on permafrost. Permafrost is viewed as one of the future climate driven process domains that may exist in Scandinavia, and that may give rise to significantly different surface and subsurface conditions than the present. Except for changes in the biosphere, permafrost may impact hydraulic, mechanical, and chemical subsurface processes and conditions. Permafrost and its influences on the subsurface conditions are thus of interest for the performance and safety assessments of deep geological waste repositories. The definition of permafrost is 'ground that stays at or below 0 deg C for at least two consecutive years'. Permafrost will effect the geological subsurface to some depth. How deep the permafrost may grow is a function of the heat balance, thermal conditions at the surface and within the ground, and the geothermal heat flux from the Earth's inner parts. The main chapters of the report summaries the knowledge on permafrost evolution, occurrence and distribution, and extracts information concerning hydrology and mechanical and chemical impacts due to permafrost related conditions. The results of a literature review are always dependent on the available literature. Concerning permafrost there is some literature available from investigations in the field of long-term repositories and some from mining industries. However, reports of these investigations are few and the bulk of permafrost literature comes from the science departments concerned with surficial processes (e.g. geomorphology, hydrology, agriculture, etc) and from engineering concerns, such as foundation of constructions and pipeline design. This focus within the permafrost research inevitably yields a biased but also an abundant amount of information on localised surficial processes and a limited amount on regional and deep permafrost characteristics. Possible conclusions are that there is

  2. Surface and subsurface conditions in permafrost areas - a literature review

    Energy Technology Data Exchange (ETDEWEB)

    Vidstrand, Patrik [Bergab, Goeteborg (Sweden)

    2003-02-01

    This report contains a summary of some of the information within existing technical and scientific literature on permafrost. Permafrost is viewed as one of the future climate driven process domains that may exist in Scandinavia, and that may give rise to significantly different surface and subsurface conditions than the present. Except for changes in the biosphere, permafrost may impact hydraulic, mechanical, and chemical subsurface processes and conditions. Permafrost and its influences on the subsurface conditions are thus of interest for the performance and safety assessments of deep geological waste repositories. The definition of permafrost is 'ground that stays at or below 0 deg C for at least two consecutive years'. Permafrost will effect the geological subsurface to some depth. How deep the permafrost may grow is a function of the heat balance, thermal conditions at the surface and within the ground, and the geothermal heat flux from the Earth's inner parts. The main chapters of the report summaries the knowledge on permafrost evolution, occurrence and distribution, and extracts information concerning hydrology and mechanical and chemical impacts due to permafrost related conditions. The results of a literature review are always dependent on the available literature. Concerning permafrost there is some literature available from investigations in the field of long-term repositories and some from mining industries. However, reports of these investigations are few and the bulk of permafrost literature comes from the science departments concerned with surficial processes (e.g. geomorphology, hydrology, agriculture, etc) and from engineering concerns, such as foundation of constructions and pipeline design. This focus within the permafrost research inevitably yields a biased but also an abundant amount of information on localised surficial processes and a limited amount on regional and deep permafrost characteristics. Possible conclusions are that

  3. New permafrost is forming around shrinking Arctic lakes, but will it last?

    Science.gov (United States)

    Briggs, Martin A.; Walvoord, Michelle Ann; McKenzie, Jeffrey M.; Voss, Clifford I.; Day-Lewis, Frederick D.; Lane, John W.

    2014-01-01

    Widespread lake shrinkage in cold regions has been linked to climate warming and permafrost thaw. Permafrost aggradation, however, has been observed within the margins of recently receded lakes, in seeming contradiction of climate warming. Here permafrost aggradation dynamics are examined at Twelvemile Lake, a retreating lake in interior Alaska. Observations reveal patches of recently formed permafrost within the dried lake margin, colocated with discrete bands of willow shrub. We test ecological succession, which alters shading, infiltration, and heat transport, as the driver of aggradation using numerical simulation of variably saturated groundwater flow and heat transport with phase change (i.e., freeze-thaw). Simulations support permafrost development under current climatic conditions, but only when net effects of vegetation on soil conditions are incorporated, thus pointing to the role of ecological succession. Furthermore, model results indicate that permafrost aggradation is transitory with further climate warming, as new permafrost thaws within seven decades.

  4. Transient thermal modeling of permafrost conditions in Southern Norway

    Directory of Open Access Journals (Sweden)

    S. Westermann

    2013-04-01

    Full Text Available Thermal modeling is a powerful tool to infer the temperature regime of the ground in permafrost areas. We present a transient permafrost model, CryoGrid 2, that calculates ground temperatures according to conductive heat transfer in the soil and in the snowpack. CryoGrid 2 is forced by operational air temperature and snow-depth products for potential permafrost areas in Southern Norway for the period 1958 to 2009 at 1 km2 spatial resolution. In total, an area of about 80 000 km2 is covered. The model results are validated against borehole temperatures, permafrost probability maps from "bottom temperature of snow" measurements and inventories of landforms indicative of permafrost occurrence. The validation demonstrates that CryoGrid 2 can reproduce the observed lower permafrost limit to within 100 m at all validation sites, while the agreement between simulated and measured borehole temperatures is within 1 K for most sites. The number of grid cells with simulated permafrost does not change significantly between the 1960s and 1990s. In the 2000s, a significant reduction of about 40% of the area with average 2 m ground temperatures below 0 °C is found, which mostly corresponds to degrading permafrost with still negative temperatures in deeper ground layers. The thermal conductivity of the snow is the largest source of uncertainty in CryoGrid 2, strongly affecting the simulated permafrost area. Finally, the prospects of employing CryoGrid 2 as an operational soil-temperature product for Norway are discussed.

  5. Quantifying Permafrost Extent, Condition, and Degradation at Department of Defense Installations in the Arctic

    Science.gov (United States)

    Edlund, C. A.

    2017-12-01

    The Department of Defense (DoD) is planning over $500M in military construction on Eielson Air Force Base (AFB) within the next three fiscal years. This construction program will expand the footprint of facilities and change the storm water management scheme, which will have second order effects on the underlying permafrost layer. These changes in permafrost will drive engineering decision making at local and regional levels, and help shape the overall strategy for military readiness in the Arctic. Although many studies have attempted to predict climate change induced permafrost degradation, very little site-specific knowledge exists on the anthropogenic effects to permafrost at this location. In 2016, the permafrost degradation rates at Eielson AFB were modeled using the Geophysics Institute Permafrost Laboratory (GIPL) 2.1 model and limited available geotechnical and climate data. Model results indicated a degradation of the discontinuous permafrost layer at Eielson AFB of up to 7 meters in depth over the next century. To further refine an understanding of the geophysics at Eielson AFB and help engineers and commanders make more informed decisions on engineering and operations in the arctic, this project established two permafrost monitoring stations near the future construction sites. Installation of the stations occurred in July 2017. Permafrost was located and characterized using two Electrical Resistivity Tomography surveys, as well as direct frost probe measurements. Using this data, the research team optimized the placement location and depth of two long term ground temperature monitoring stations, and then installed the stations for data collection. The data set generated by these stations are the first of their kind at Eielson AFB, and represent the first systematic effort in the DoD to quantify permafrost condition before, during, and after construction and other anthropogenic activities in order to fully understand the effects of that activity in the

  6. Distribution of near-surface permafrost in Alaska: estimates of present and future conditions

    Science.gov (United States)

    Pastick, Neal J.; Jorgenson, M. Torre; Wylie, Bruce K.; Nield, Shawn J.; Johnson, Kristofer D.; Finley, Andrew O.

    2015-01-01

    High-latitude regions are experiencing rapid and extensive changes in ecosystem composition and function as the result of increases in average air temperature. Increasing air temperatures have led to widespread thawing and degradation of permafrost, which in turn has affected ecosystems, socioeconomics, and the carbon cycle of high latitudes. Here we overcome complex interactions among surface and subsurface conditions to map nearsurface permafrost through decision and regression tree approaches that statistically and spatially extend field observations using remotely sensed imagery, climatic data, and thematic maps of a wide range of surface and subsurface biophysical characteristics. The data fusion approach generated medium-resolution (30-m pixels) maps of near-surface (within 1 m) permafrost, active-layer thickness, and associated uncertainty estimates throughout mainland Alaska. Our calibrated models (overall test accuracy of ~85%) were used to quantify changes in permafrost distribution under varying future climate scenarios assuming no other changes in biophysical factors. Models indicate that near-surface permafrost underlies 38% of mainland Alaska and that near-surface permafrost will disappear on 16 to 24% of the landscape by the end of the 21st Century. Simulations suggest that near-surface permafrost degradation is more probable in central regions of Alaska than more northerly regions. Taken together, these results have obvious implications for potential remobilization of frozen soil carbon pools under warmer temperatures. Additionally, warmer and drier conditions may increase fire activity and severity, which may exacerbate rates of permafrost thaw and carbon remobilization relative to climate alone. The mapping of permafrost distribution across Alaska is important for land-use planning, environmental assessments, and a wide-array of geophysical studies.

  7. A permafrost distribution estimate for the Southern Alps, New Zealand, inferred from topoclimatic conditions at rock glacier sites

    Science.gov (United States)

    Sattler, Katrin; Mackintosh, Andrew; Anderson, Brian; Norton, Kevin; de Róiste, Mairead

    2014-05-01

    The presence of numerous rock glaciers and perennial snow patches indicate the existence of discontinuous alpine permafrost in New Zealand's Southern Alps. However, research on the geographic extent of permafrost in the South Island has been limited. Existing estimates are restricted to single mountain ranges or focus on steep bedrock permafrost. A recent global-scale estimate has not been evaluated by local observations. We present the results of a regional, spatially distributed permafrost estimate for the Southern Alps, focusing on debris-covered slopes. Permafrost distribution modelling was based on the statistical evaluation of 280 active and relict rock glaciers. Logistic regression identified characteristic topoclimatic conditions at the head area of presently active rock glaciers. Statistical relationships between permafrost presence, mean annual air temperature, and potential incoming solar radiation in snow-free months were subsequently used to calculate the spatially distributed probability of permafrost occurrence. The potential permafrost extent was delineated using a probability threshold of ≥ 0.6. Model results suggest that topoclimatic conditions are favourable for permafrost occurrence above ~ 2000 m a.s.l. in the central Southern Alps and above ~ 2150 m a.s.l. in the northern ranges. This gradient in permafrost altitude reflects the warmer climate at lower latitudes. Model results were locally validated by BTS (bottom temperature of snow cover) data derived from two-year continuous ground surface temperature (GST) measurements in the Ben Ohau Range, central Southern Alps. Applicability of BTS measurements for permafrost mapping had not been tested previously in the maritime setting of New Zealand, where common warm spells during winter can result in isothermal snow pack conditions, preventing the inference of late-winter equilibrium temperatures. BTS-indicated permafrost sites were in good agreement with modelled permafrost probabilities at the

  8. Impact of global warming on permafrost conditions in a coupled GCM

    DEFF Research Database (Denmark)

    Stendel, M.; Christensen, J. H.

    2002-01-01

    A climate change scenario experiment conducted with the state-of-the-art coupled atmosphere-ocean general circulation model ECHAM4/OPYC3 is analysed with the objective to quantify changes in present-day Arctic permafrost conditions. An efficient procedure is adopted which overcomes the many...... emissions (SRES A2 issued by IPCC), we estimate the amounts that the permafrost zones moves poleward and how the thickness of the active layer deepens in response to the global warming by the end of the 21st century. The simulation indicates a 30-40% increase in active-layer thickness for most...

  9. Soil Physical and Environmental Conditions Controlling Patterned-Ground Variability at a Continuous Permafrost Site, Svalbard

    DEFF Research Database (Denmark)

    Watanabe, Tatsuya; Matsuoka, Norikazu; Christiansen, Hanne Hvidtfeldt

    2017-01-01

    This study examines soil physical and environmental conditions controlling patterned-ground variability on an alluvial fan in a continuous permafrost landscape, at Adventdalen, Svalbard. On-site monitoring of ground temperature, soil moisture and snow depth, laboratory analyses of soil physical...

  10. Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export.

    Science.gov (United States)

    Olefeldt, David; Roulet, Nigel T

    2014-10-01

    Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon (DOC) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of each type. We show that hydrological setting is key to observed differences in magnitude, timing, and chemical composition of DOC export between permafrost and nonpermafrost peatland types, and that these differences influence the export of DOC of larger catchments even when peatlands are minor catchment components. In many aspects, DOC export from a studied peatland permafrost plateau was similar to that of a forested upland catchment. Similarities included low annual export (2-3 g C m(-2) ) dominated by the snow melt period (~70%), and how substantial DOC export following storms required wet antecedent conditions. Conversely, nonpermafrost fens had higher DOC export (7 g C m(-2) ), resulting from sustained hydrological connectivity during summer. Chemical composition of catchment DOC export arose from the mixing of highly aromatic DOC from organic soils from permafrost plateau soil water and upland forest surface horizons with nonaromatic DOC from mineral soil groundwater, but was further modulated by fens. Increasing aromaticity from fen inflow to outlet was substantial and depended on both water residence time and water temperature. The role of fens as catchment biogeochemical hotspots was further emphasized by their capacity for sulfate retention. As a result of fen characteristics, a 4% fen cover in a mixed catchment was responsible for 34% higher DOC export, 50% higher DOC concentrations and ~10% higher DOC aromaticity at the catchment outlet during summer compared to a nonpeatland upland catchment. Expansion of fens due to thaw thus has potential to influence landscape C cycling by increasing fen capacity to act as biogeochemical hotspots, amplifying aquatic C cycling, and

  11. Collaborative Research. Quantifying Climate Feedbacks of the Terrestrial Biosphere under Thawing Permafrost Conditions in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Qianlai [Purdue Univ., West Lafayette, IN (United States); Schlosser, Courtney [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Melillo, Jerry [Marine Biological Lab. (MBL), Woods Hole, MA (United States); Walter, Katey [Univ. of Alaska, Fairbanks, AK (United States)

    2015-09-15

    Our overall goal is to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically-forced climate warming, and the conditions under which these emissions provide a strong feedback mechanism to global climate warming. This goal is motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes to the landscape of wetlands and lakes, especially thermokarst (thaw) lakes, across the Arctic. Through a suite of numerical experiments that encapsulate the fundamental processes governing methane emissions and carbon exchanges – as well as their coupling to the global climate system - we intend to test the following hypothesis in the proposed research: There exists a climate warming threshold beyond which permafrost degradation becomes widespread and stimulates large increases in methane emissions (via thermokarst lakes and poorly-drained wetland areas upon thawing permafrost along with microbial metabolic responses to higher temperatures) and increases in carbon dioxide emissions from well-drained areas. Besides changes in biogeochemistry, this threshold will also influence global energy dynamics through effects on surface albedo, evapotranspiration and water vapor. These changes would outweigh any increased uptake of carbon (e.g. from peatlands and higher plant photosynthesis) and would result in a strong, positive feedback to global climate warming.

  12. Collaborative Research: Quantifying Climate Feedbacks of the Terrestrial Biosphere under Thawing Permafrost Conditions in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, Jerry [Marine Biological Lab., Woods Hole, MA (United States)

    2017-12-12

    Our overall goal in this research was to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically-forced climate warming, and the conditions under which these emissions provide a strong feedback mechanism to global climate warming. This goal was motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes to the landscape of wetlands and lakes, especially thermokarst (thaw) lakes, across the Arctic. Through a suite of numerical experiments that encapsulate the fundamental processes governing methane emissions and carbon exchanges – as well as their coupling to the global climate system - we tested the following hypothesis in the proposed research: There exists a climate warming threshold beyond which permafrost degradation becomes widespread and stimulates large increases in methane emissions (via thermokarst lakes and poorly-drained wetland areas upon thawing permafrost along with microbial metabolic responses to higher temperatures) and increases in carbon dioxide emissions from well-drained areas. Besides changes in biogeochemistry, this threshold will also influence global energy dynamics through effects on surface albedo, evapotranspiration and water vapor. These changes would outweigh any increased uptake of carbon (e.g. from peatlands and higher plant photosynthesis) and would result in a strong, positive feedback to global climate warming. In collaboration with our Purdue and MIT colleagues, we have attempted to quantify global climate warming effects on land-atmosphere interactions, land-river network interactions, permafrost degradation, vegetation shifts, and land use influence water, carbon, and nitrogen fluxes to and from terrestrial ecosystems in the pan-arctic along with their

  13. Effects of Aspergillus niger inoculum concentration upon the kinetics of starchy wastewater pretreatment in a tanks-in-series bioreactor under transitory conditions

    Directory of Open Access Journals (Sweden)

    L. Coulibaly

    2007-12-01

    Full Text Available This paper discusses the effects of three Aspergillus niger inoculum concentrations (0.12, 2.3 and 3.6 g/l upon the kinetics of starch pretreatment under aerobic and transitory conditions using a tanks-in-series reactor. A synthetic wastewater containing starch as model polysaccharide was fed into the reactor system to study this polymer transformation by Aspergillus niger. Starch and metabolites (oligosaccharides with a molecular weight lower than 1 kDa in the individual reactors were quantified respectively by the starch iodine complex (SIC and anthrone methods. Enzyme activities were characterised with API ZYM kits. Starch degradation and metabolite accumulation were both influenced by both fungal inoculum and reactor HRT. Starch degradation improved from 34 to 99% with a parallel in increase inoculum concentration from 0.12 to 3.6 g/l. An overall of 400 mg/l of metabolites accumulated in the reactor system. A. niger secreted both extracellular and cell-wall-bound enzymes among which amylases.

  14. Fatty Acid Composition of Fourteen Wood-decaying Basidiomycete Species Growing in Permafrost Conditions

    Directory of Open Access Journals (Sweden)

    Daniil N. Olennikov

    2014-03-01

    Full Text Available The fatty acid (FA compositions of 14 wild wood-decaying basidiomycete species (Bjerkandera adusta, Daedaleopsis septentrionalis, Dichomitus squalens, Inonotus hispidus, I.radiatus, Irpex lacteus, Fomitopsis cajanderi, F.pinicola, F. rosea, Gloeophyllum protractum, Lenzites betulina, Phellinus pini, Trametes gibbosa, T. ochracea growing in permafrost conditions in Katanga region (Russian Federation were investigated using GC-MS. Generally, C18:2 ω 6 (linoleic acid, C18:1 ω 9 (oleic acid, C16:0 (palmitic acid and C20:0 (arachinic acid were found to be the major FA in fungal species. Data about chemical components of Daedaleopsis septentrionalis , Fomitopsis cajanderi and Gloeophyllum protractum were obtained at the first time. Increased level of degree of FA unsaturation was probably a result of extreme environmental conditions.

  15. Field training for permafrost students in the cold-climate conditions

    Science.gov (United States)

    Leibman, M.

    2009-04-01

    We all know how complicated is organizing expeditions to the Arctic, especially to the remote areas with continuous permafrost, tundra landscapes, expensive helicopters, and extreme living conditions. But this cannot be the reason to deprive students of studying the nature. There is a serious problem with computer modeling becoming a main research instrument. Often young people involved in such modeling have never seen the object of their modeling. Some of us are "remnants" of the epoch before computer and satellite technologies when field data was the main source of mapping information, small-scale maps were based on field mapping. This knowledge is getting lost with the experts getting retired. This is the reason for involving students into field research as much and as soon as possible. Arctic expeditions often mean absence of usual amenities in living conditions, exposure to weather extremes, bugs and simple meal. These complications make each bit of field data be of high-hourly-rate. That is why teaching the methods of field study is very important, to make each trip most effective and reduce costs of each bit of information. These methods include both science and logistic issues. There are two more aspects in field training: (1) students and teachers from different countries meeting in field learn to identify natural objects and conciliate positions and terminology; and (2) students and teachers from different disciplines learn to conciliate understanding of each others study subjects. Examples of field research stations in Russian Arctic where interdisciplinary studies are ongoing for many years with participation of graduate and postgraduate students show the effectiveness of the above mentioned approach. In the north of West Siberia there are four polygons serving as a base for associated research of permafrost geologists, geographers, biologists, geochemists and more. The system is built in which basic role is shifting from one subject to the other

  16. Paleo-Eskimo kitchen midden preservation in permafrost under future climate conditions at Qajaa, West Greenland

    DEFF Research Database (Denmark)

    Elberling, Bo; Matthiesen, Henning; Jørgensen, Christian Juncher

    2011-01-01

    characteristics measured in situ and from permafrost cores. Measurements of thermal properties, heat generation, oxygen consumption and CO2 production show that the kitchen midden can be characterized as peat but produces 4–7 times more heat than natural sediment. An analytical model from permafrost research has...

  17. What's down below? Current and potential future applications of geophysical techniques to identify subsurface permafrost conditions (Invited)

    Science.gov (United States)

    Douglas, T. A.; Bjella, K.; Campbell, S. W.

    2013-12-01

    For infrastructure design, operations, and maintenance requirements in the North the ability to accurately and efficiently detect the presence (or absence) of ground ice in permafrost terrains is a serious challenge. Ground ice features including ice wedges, thermokarst cave-ice, and segregation ice are present in a variety of spatial scales and patterns. Currently, most engineering applications use borehole logging and sampling to extrapolate conditions at the point scale. However, there is high risk of over or under estimating the presence of frozen or unfrozen features when relying on borehole information alone. In addition, boreholes are costly, especially for planning linear structures like roads or runways. Predicted climate warming will provide further challenges for infrastructure development and transportation operations where permafrost degradation occurs. Accurately identifying the subsurface character in permafrost terrains will allow engineers and planners to cost effectively create novel infrastructure designs to withstand the changing environment. There is thus a great need for a low cost rapidly deployable, spatially extensive means of 'measuring' subsurface conditions. Geophysical measurements, both terrestrial and airborne, have strong potential to revolutionize our way of mapping subsurface conditions. Many studies in continuous and discontinuous permafrost have used geophysical measurements to identify discrete features and repeatable patterns in the subsurface. The most common measurements include galvanic and capacitive coupled resistivity, ground penetrating radar, and multi frequency electromagnetic induction techniques. Each of these measurements has strengths, weaknesses, and limitations. By combining horizontal geophysical measurements, downhole geophysics, multispectral remote sensing images, LiDAR measurements, and soil and vegetation mapping we can start to assemble a holistic view of how surface conditions and standoff measurements

  18. Mapping surficial geology and assessment of permafrost conditions under the Iqaluit airport, Nunavut, Canada

    Science.gov (United States)

    Mathon-Dufour, V.; Allard, M.; Leblanc, A.; L'Hérault, E.; Oldenborger, G. A.; Sladen, W. E.

    2012-12-01

    Formerly, characterization of permafrost conditions was minimal before the construction of infrastructures. It was assumed that the permafrost would forever remain a solid substrate. Before global warming, transportation infrastructures were not designed, especially in terms of materials and dimensions, to withstand without damage an increased input of heat in the soil. Iqaluit airport, the hub of the eastern Canadian Arctic, is currently affected by thawing permafrost. In fact, the runway, taxiways and apron are affected by differential settlements resulting from the presence of localized ice-rich soils. This study uses a GIS approach that makes up for the absence of appropriate characterization before the construction of the airport during WWII and in the 1950s. Mapping of surficial geology, hydrography and landforms indicative of the presence of ground ice (e.g. tundra polygons) was produced by interpreting aerial photographs dating back from the initial phases of construction (1948) and photographs taken at intervals since then, to the most recent high-resolution satellite images. Subsequent map analysis shows that the original terrain conditions prevailing before the construction of the airport have a significant impact on the current stability of the infrastructure. Data integration allowed us to summarize the main problems affecting the Iqaluit airport which are: 1) Differential settlements associated with pre-construction drainage network 2) Cracking due to thermal contraction, 3) Linear depressions associated with ice wedge degradation and 4) Sink holes. Most of the sectors affected by differential settlements and instabilities are perfectly coincident with the original streams and lakes network that has been filled to increase the size of the runway, taxiways and the apron. In addition, the runway is affected by intense frost cracking. Similarities with nearby natural terrain suggest that the network pattern of the cracks follows pre-existing ice wedges

  19. Difference flow measurements under permafrost conditions in the Kangerlussuaq area, West Greenland

    Science.gov (United States)

    Lehtinen, A. M.; Rouhiainen, P.; Pöllänen, J.; Heikkinen, P.; Ruskeeniemi, T.; Claesson Liljedahl, L.

    2012-12-01

    length. The measurements were carried out in both natural and pumped conditions. The risk of the drillhole freezing over in the permafrost section was high and therefore, no measurements were made in the upper part of the drillhole (from 0 to depth of 172 m). Lack of measurable water conductivity between 172-390 m indicates that permafrost may extend down to a depth of 350 m in DH-GAP04. This was later confirmed by temperature profiling with a Distributed Temperature Sensing (DTS) cable. The aim of the measurements was to find high transmissive fractures, which would define the place for water sampling, i.e. the location for the packers in the drillhole. In total, nine high or moderately transmissive fractures were found in the drillhole. Transmissivities varied between 2.35E-9- 3.29E-6 m2s-1 and the highest transmissivity was in a fracture zone at the depth of 564 m. This fracture zone was selected as the main target for the hydrogeochemical investigations, i.e. this section was chosen as the primary water sampling section, and was later packed off with a two-packer system.

  20. Circum-Arctic Map of Permafrost and Ground-Ice Conditions, Version 2

    Data.gov (United States)

    National Aeronautics and Space Administration — The Circum-Arctic permafrost and ground ice map is available via ftp in ESRI Shapefile format and Equal-Area Scalable Earth Grid (EASE-Grid) format. See the Format...

  1. Circum-Arctic Map of Permafrost and Ground-Ice Conditions, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Circum-Arctic permafrost and ground ice map is available via ftp in ESRI Shapefile format and Equal-Area Scalable Earth Grid (EASE-Grid) format. See the Format...

  2. Preservation of collagen and bioapatite fractions extracted from bison teeth in permafrost conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cherkinsky, Alexander [Center for Applied Isotope Studies, University of Georgia, GA (United States); Glassburn, Crystal L. [Anthropology Department, University of Alaska, Fairbanks, AK (United States); Reuther, Joshua [Anthropology Department, University of Alaska, Fairbanks, AK (United States); University of Alaska, Museum of the North, Fairbanks, AK (United States)

    2015-10-15

    This research addresses the stability of bioapatite and collagen fractions of AMS dated steppe bison (Bison priscus) teeth. Through the course of other research, 8 prehistoric bison molars were submitted for AMS dating of fractions of collagen extracted from the dentine of each tooth. Because the teeth were well preserved and collagen yields were relatively high during the initial analysis, it provided an opportunity to further research differences between AMS dates produced on collagen from dentine and bioapatite fractions from enamel. The specimens were recovered from late Quaternary sediments of the Lost Chicken Creek drainage in east-central Alaska. All of the samples were very well preserved and gave high enough yield of carbon from both fractions. The {sup 14}C/{sup 13}C ratio was measured using 0.5 MV tandem AMS system. The {sup 14}C age of the samples varied across age ranges between 17,360 ± 50 and 43,370 ± 300 non-calibrated years BP. Such a wide range of ages allows us estimate the stability of each fraction in subarctic permafrost conditions. The results of analyses have shown that {sup 14}C ages of bioapatite fraction are rejuvenated as a result of isotopic exchange with the younger carbon from the soil solutions. The dating of bioapatite from the samples collected in the boreal climate of Alaska is possible only with a certain correction for the isotope fractionation.

  3. DOE Final Report on Collaborative Research. Quantifying Climate Feedbacks of the Terrestrial Biosphere under Thawing Permafrost Conditions in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Qianlai [Purdue Univ., West Lafayette, IN (United States); Schlosser, C. Adam [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Melillo, Jerry M. [Marine Biological Lab. (MBL), Woods Hole, MA (United States); Anthony, Katey Walter [Univ. of Alaska, Fairbanks, AK (United States); Kicklighter, David [Marine Biological Lab. (MBL), Woods Hole, MA (United States); Gao, Xiang [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2015-11-03

    Our overall goal is to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically-forced climate warming, and the conditions under which these emissions provide a strong feedback mechanism to global climate warming. This goal is motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes to the landscape of wetlands and lakes, especially thermokarst (thaw) lakes, across the Arctic. Through a suite of numerical experiments that encapsulate the fundamental processes governing methane emissions and carbon exchanges – as well as their coupling to the global climate system - we intend to test the following hypothesis in the proposed research: There exists a climate warming threshold beyond which permafrost degradation becomes widespread and stimulates large increases in methane emissions (via thermokarst lakes and poorly-drained wetland areas upon thawing permafrost along with microbial metabolic responses to higher temperatures) and increases in carbon dioxide emissions from well-drained areas. Besides changes in biogeochemistry, this threshold will also influence global energy dynamics through effects on surface albedo, evapotranspiration and water vapor. These changes would outweigh any increased uptake of carbon (e.g. from peatlands and higher plant photosynthesis) and would result in a strong, positive feedback to global climate warming.

  4. Impact of global warming on permafrost conditions in a coupled GCM

    DEFF Research Database (Denmark)

    Stendel, M.; Christensen, J. H.

    2002-01-01

    emissions (SRES A2 issued by IPCC), we estimate the amounts that the permafrost zones moves poleward and how the thickness of the active layer deepens in response to the global warming by the end of the 21st century. The simulation indicates a 30-40% increase in active-layer thickness for most...

  5. 100 kGy gamma-affected microbial communities within the ancient Arctic permafrost under simulated Martian conditions.

    Science.gov (United States)

    Cheptsov, Vladimir S; Vorobyova, Elena A; Manucharova, Natalia A; Gorlenko, Mikhail V; Pavlov, Anatoli K; Vdovina, Maria A; Lomasov, Vladimir N; Bulat, Sergey A

    2017-11-01

    This research aimed to investigate the viability and biodiversity of microbial communities within ancient Arctic permafrost after exposure to a gamma-radiation dose of 100 kGy at low temperature (- 50 °C), low pressure (1 Torr) and dehydration conditions. The main objective was to assess the possibility for long-term survival of Earth-bound microorganisms in the subsurface of Martian regolith or inside small space bodies at constant absorption and accumulation of the gamma radiation dose. Investigated microbial communities had shown high resistance to a simulated Martian environment. After irradiation the total count of prokaryotic cells and number of metabolically active bacterial cells remained at the control level, while the number of bacterial CFUs decreased by 2 orders of magnitude, and the number of metabolically active cells of archaea decreased threefold. Besides, the abundance of culturable bacteria after irradiation was kept at a high level: not less than 3.7 × 10 5  cells/g. Potential metabolic activity of irradiated microbial communities in general were higher than in the control sample. A fairly high biodiversity of bacteria was detected in the exposed sample of permafrost, although the microbial community structure underwent significant changes after irradiation. In particular, actinobacteria populations of the genus Arthrobacter, which was not revealed in the control samples, became predominant in bacterial communities following the exposure. The results of the study testify that long-term preservation of microbial life inside Martian permafrost is possible. The data obtained can also be evaluated from the perspective of the potential for discovering viable Earth-bound microorganisms on other objects in the Solar system and inside of small bodies in outer space.

  6. Barriers of repository under the conditions of underground isolation of heat releasing radioactive waste in permafrost

    International Nuclear Information System (INIS)

    Kazakov, A.N.; Fedorovich, L.N.

    1995-01-01

    The main positions and the leading principle of the ensuring of the environmental safety of the method of the underground isolation of radioactive waste in permafrost rock are presented in this work and it is shown here the peculiarities in realization of the principle of the multibarrier protection. It is substantiated here the principle of the optimal time of the capacity for work of the repository's engineered barriers. The possibility of the exclusion of the radionuclides migration beyond the working volume of the repository during the time of the potential danger of radioactive waste is also substantiated in these papers

  7. A 20-year record (1998-2017) of permafrost, active layer and meteorological conditions at a high Arctic permafrost research site (Bayelva, Spitsbergen)

    Science.gov (United States)

    Boike, Julia; Juszak, Inge; Lange, Stephan; Chadburn, Sarah; Burke, Eleanor; Overduin, Pier Paul; Roth, Kurt; Ippisch, Olaf; Bornemann, Niko; Stern, Lielle; Gouttevin, Isabelle; Hauber, Ernst; Westermann, Sebastian

    2018-03-01

    Most permafrost is located in the Arctic, where frozen organic carbon makes it an important component of the global climate system. Despite the fact that the Arctic climate changes more rapidly than the rest of the globe, observational data density in the region is low. Permafrost thaw and carbon release to the atmosphere are a positive feedback mechanism that can exacerbate global warming. This positive feedback functions via changing land-atmosphere energy and mass exchanges. There is thus a great need to understand links between the energy balance, which can vary rapidly over hourly to annual timescales, and permafrost, which changes slowly over long time periods. This understanding thus mandates long-term observational data sets. Such a data set is available from the Bayelva site at Ny-Ålesund, Svalbard, where meteorology, energy balance components and subsurface observations have been made for the last 20 years. Additional data include a high-resolution digital elevation model (DEM) that can be used together with the snow physical information for snowpack modeling and a panchromatic image. This paper presents the data set produced so far, explains instrumentation, calibration, processing and data quality control, as well as the sources for various resulting data sets. The resulting data set is unique in the Arctic and serves as a baseline for future studies. The mean permafrost temperature is -2.8 °C, with a zero-amplitude depth at 5.5 m (2009-2017). Since the data provide observations of temporally variable parameters that mitigate energy fluxes between permafrost and atmosphere, such as snow depth and soil moisture content, they are suitable for use in integrating, calibrating and testing permafrost as a component in earth system models.The presented data are available in the Supplement for this paper (time series) and through the PANGAEA and Zenodo data portals: time series (https://doi.org/10.1594/PANGAEA.880120, https://zenodo.org/record/1139714) and

  8. A 20-year record (1998–2017 of permafrost, active layer and meteorological conditions at a high Arctic permafrost research site (Bayelva, Spitsbergen

    Directory of Open Access Journals (Sweden)

    J. Boike

    2018-03-01

    Full Text Available Most permafrost is located in the Arctic, where frozen organic carbon makes it an important component of the global climate system. Despite the fact that the Arctic climate changes more rapidly than the rest of the globe, observational data density in the region is low. Permafrost thaw and carbon release to the atmosphere are a positive feedback mechanism that can exacerbate global warming. This positive feedback functions via changing land–atmosphere energy and mass exchanges. There is thus a great need to understand links between the energy balance, which can vary rapidly over hourly to annual timescales, and permafrost, which changes slowly over long time periods. This understanding thus mandates long-term observational data sets. Such a data set is available from the Bayelva site at Ny-Ålesund, Svalbard, where meteorology, energy balance components and subsurface observations have been made for the last 20 years. Additional data include a high-resolution digital elevation model (DEM that can be used together with the snow physical information for snowpack modeling and a panchromatic image. This paper presents the data set produced so far, explains instrumentation, calibration, processing and data quality control, as well as the sources for various resulting data sets. The resulting data set is unique in the Arctic and serves as a baseline for future studies. The mean permafrost temperature is −2.8 °C, with a zero-amplitude depth at 5.5 m (2009–2017. Since the data provide observations of temporally variable parameters that mitigate energy fluxes between permafrost and atmosphere, such as snow depth and soil moisture content, they are suitable for use in integrating, calibrating and testing permafrost as a component in earth system models.The presented data are available in the Supplement for this paper (time series and through the PANGAEA and Zenodo data portals: time series (https://doi.org/10.1594/PANGAEA.880120, https

  9. Extreme fire events are related to previous-year surface moisture conditions in permafrost-underlain larch forests of Siberia

    International Nuclear Information System (INIS)

    Forkel, Matthias; Beer, Christian; Thonicke, Kirsten; Cramer, Wolfgang; Bartalev, Sergey; Schmullius, Christiane

    2012-01-01

    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 km 2 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. (letter)

  10. The potential for cold climate conditions and permafrost in Forsmark in the next 60 000 years

    International Nuclear Information System (INIS)

    Brandefelt, Jenny; Naeslund, Jens-Ove; Zhang, Qiong; Hartikainen, Juha

    2013-05-01

    This report presents results of a study devoted to extend the current knowledge of the climate in Sweden in the next ∼60,000 years (60 ka). Specifically, the potential of cold climate and permafrost development in south-central Sweden, and in the Forsmark region, over this time horizon was investigated. The climate system is an interactive system consisting of five major components: the atmosphere, the hydrosphere, the cryo sphere, the land surface and the biosphere, forced or influenced by various external forcing mechanisms, of which the most important is the Sun. Also the direct effect of human activities on the climate system is considered an external forcing. The latitudinal and seasonal distribution of incoming solar radiation (insolation) varies on millennial time scales due to variations in the Earth's orbit and axial tilt. These variations, together with variations in the atmospheric CO 2 concentration, are viewed as two main factors in determining the climate variation between interglacial (warmer) and glacial (colder) climates. Summer insolation at high northern latitudes is at a minimum 17 ka and 54 ka after present (AP). These periods were therefore identified as potential future periods of cold climate conditions in high northern latitudes in general and in south-central Sweden in particular. Due to human emissions of carbon to the atmosphere, the atmospheric CO 2 concentration is currently 392 ppmv (2011 AD), a substantial increase as compared to the range of atmospheric CO 2 concentrations of 180-295 ppmv found in ice cores for the last 400 ka. The future atmospheric CO 2 concentration is determined by i) future human carbon emissions to the atmosphere, ii) possible emissions due to feedbacks in the climate system, and iii) by the global carbon cycle. To investigate the potential of cold climate conditions in south-central Sweden in the next 60 ka the future air temperature in Forsmark was estimated based on simulations with an Earth system model

  11. The potential for cold climate conditions and permafrost in Forsmark in the next 60 000 years

    Energy Technology Data Exchange (ETDEWEB)

    Brandefelt, Jenny; Naeslund, Jens-Ove [Svensk Kaernbraenslehantering, Stockholm (Sweden); Zhang, Qiong [Dept. of Meteorology, Stockholm Univ., Stockholm (Sweden); Hartikainen, Juha [School of Engineering, Aalto Univ., Aalto (Finland)

    2013-05-15

    This report presents results of a study devoted to extend the current knowledge of the climate in Sweden in the next {approx}60,000 years (60 ka). Specifically, the potential of cold climate and permafrost development in south-central Sweden, and in the Forsmark region, over this time horizon was investigated. The climate system is an interactive system consisting of five major components: the atmosphere, the hydrosphere, the cryo sphere, the land surface and the biosphere, forced or influenced by various external forcing mechanisms, of which the most important is the Sun. Also the direct effect of human activities on the climate system is considered an external forcing. The latitudinal and seasonal distribution of incoming solar radiation (insolation) varies on millennial time scales due to variations in the Earth's orbit and axial tilt. These variations, together with variations in the atmospheric CO{sub 2} concentration, are viewed as two main factors in determining the climate variation between interglacial (warmer) and glacial (colder) climates. Summer insolation at high northern latitudes is at a minimum 17 ka and 54 ka after present (AP). These periods were therefore identified as potential future periods of cold climate conditions in high northern latitudes in general and in south-central Sweden in particular. Due to human emissions of carbon to the atmosphere, the atmospheric CO{sub 2} concentration is currently 392 ppmv (2011 AD), a substantial increase as compared to the range of atmospheric CO{sub 2} concentrations of 180-295 ppmv found in ice cores for the last 400 ka. The future atmospheric CO{sub 2} concentration is determined by i) future human carbon emissions to the atmosphere, ii) possible emissions due to feedbacks in the climate system, and iii) by the global carbon cycle. To investigate the potential of cold climate conditions in south-central Sweden in the next 60 ka the future air temperature in Forsmark was estimated based on

  12. Permafrost Hazards and Linear Infrastructure

    Science.gov (United States)

    Stanilovskaya, Julia; Sergeev, Dmitry

    2014-05-01

    The international experience of linear infrastructure planning, construction and exploitation in permafrost zone is being directly tied to the permafrost hazard assessment. That procedure should also consider the factors of climate impact and infrastructure protection. The current global climate change hotspots are currently polar and mountain areas. Temperature rise, precipitation and land ice conditions change, early springs occur more often. The big linear infrastructure objects cross the territories with different permafrost conditions which are sensitive to the changes in air temperature, hydrology, and snow accumulation which are connected to climatic dynamics. One of the most extensive linear structures built on permafrost worldwide are Trans Alaskan Pipeline (USA), Alaska Highway (Canada), Qinghai-Xizang Railway (China) and Eastern Siberia - Pacific Ocean Oil Pipeline (Russia). Those are currently being influenced by the regional climate change and permafrost impact which may act differently from place to place. Thermokarst is deemed to be the most dangerous process for linear engineering structures. Its formation and development depend on the linear structure type: road or pipeline, elevated or buried one. Zonal climate and geocryological conditions are also of the determining importance here. All the projects are of the different age and some of them were implemented under different climatic conditions. The effects of permafrost thawing have been recorded every year since then. The exploration and transportation companies from different countries maintain the linear infrastructure from permafrost degradation in different ways. The highways in Alaska are in a good condition due to governmental expenses on annual reconstructions. The Chara-China Railroad in Russia is under non-standard condition due to intensive permafrost response. Standards for engineering and construction should be reviewed and updated to account for permafrost hazards caused by the

  13. Boron isotope fractionation in groundwaters as an indicator of past permafrost conditions in the fractured crystalline bedrock of the fennoscandian shield.

    Science.gov (United States)

    Casanova, Joël; Négrel, Philippe; Blomqvist, Runar

    2005-01-01

    The Fennoscandian Shield has been subjected to several glaciations over the past million years, the last of which (Weichselian Ice Age) ended only at about 10Ka. Here we used boron isotopes and B contents to (a) establish the degree of water-rock interaction (WRI) and (b) clarify freezing processes within groundwaters from the Aspo site in Sweden and from various sites in Finland. The high delta(11)B values recorded by all groundwaters (up to 51.9 per thousand) including diluted, boron-poor, inland groundwaters suggest selective uptake of (10)B into ice related to freezing processes under permafrost conditions. According to co-existing ice and residual brines in a Canadian frozen mine, this fractionation process, enhanced by Rayleigh fractionation, can generate a natural field of isotopic variation around 60 per thousand and provides a new application of B isotope that makes possible to easily characterise groundwaters that underwent past permafrost conditions.

  14. Permanent and transitory oil volatility and aggregate investment in Malaysia

    International Nuclear Information System (INIS)

    Ibrahim, Mansor H.; Ahmed, Huson Joher Ali

    2014-01-01

    This paper investigates the relation between aggregate investment and oil volatility and its permanent and transitory components for a developing country, Malaysia. In the paper, the components generalized autoregressive conditional heteroskedasticity (CGARCH) model is utilized to decompose conditional oil volatility into permanent oil volatility and transitory oil volatility. Respectively reflecting fundamental-driven and random shifts in oil volatility, they are expected to exert differential effects on aggregate investment. Adopting a vector autoregression (VAR) framework to allow feedback effects between aggregate investment and its determinants, the paper documents evidence supporting the adverse effects of conditional oil volatility, permanent oil volatility and transitory oil volatility on aggregate investment and real output. Interestingly, contrary to the findings for the developed markets (US and OECD), the real effects of permanent oil volatility tend to be stronger. These findings are reasonably robust to variable specification and measurements in the VAR system. Hence, there is an indication that heightened oil volatility accounts for the slumps in Malaysia's aggregate investment after the Asian financial crisis. - Highlights: • Examines the role of oil volatility in Malaysia's aggregate investment. • Makes distinction between permanent and temporary volatility using CGARCH. • Both volatility components depress investment. • Permanent volatility has larger adverse effects. • Results are robust to alternative model specifications

  15. Geophysical Investigations of Saline Permafrost at Ilulissat, Greenland

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas; Foged, Niels Nielsen; Butzbach, Rune

    2008-01-01

    The technical properties and general state of permafrost in Greenland is not well documented. A new coordinated investigation has been initiated, for ground temperature measurements and permafrost mapping in Greenlandic towns in sporadic, discontinuous and continuous permafrost zones. We present...... properties, and the sediments have a limited heat capacity available, should the temperature conditions change....

  16. Transition problems and play as transitory activity

    DEFF Research Database (Denmark)

    Broström, Stig

    2005-01-01

    functions, among others the development of children's learning motive. From the view of activity theori, transition to formal education entails crossing boundaries from the activity system play to the activity system of school learning. The transition can be facilitated by developing a 'transitory activity......Because too many children experience the transition to school as a culture shock, during the past decade teachers have implemented so-called transition activities in order to bridge the gap betwen pre-school and schoo. However, transition to school also calls for a development of higher mental...... system', which mediates between the two systems, ensuring that the result of one system serves as a tool for the next. Advanced forms of play might make up a transitory activity system. The paper describes different forms of play crossing the boundaies of role play (frame-play, aesthetic theme play...

  17. Review article: Inferring permafrost and permafrost thaw in the mountains of the Hindu Kush Himalaya region

    Science.gov (United States)

    Gruber, Stephan; Fleiner, Renate; Guegan, Emilie; Panday, Prajjwal; Schmid, Marc-Olivier; Stumm, Dorothea; Wester, Philippus; Zhang, Yinsheng; Zhao, Lin

    2017-01-01

    The cryosphere reacts sensitively to climate change, as evidenced by the widespread retreat of mountain glaciers. Subsurface ice contained in permafrost is similarly affected by climate change, causing persistent impacts on natural and human systems. In contrast to glaciers, permafrost is not observable spatially and therefore its presence and possible changes are frequently overlooked. Correspondingly, little is known about permafrost in the mountains of the Hindu Kush Himalaya (HKH) region, despite permafrost area exceeding that of glaciers in nearly all countries. Based on evidence and insight gained mostly in other permafrost areas globally, this review provides a synopsis on what is known or can be inferred about permafrost in the mountains of the HKH region. Given the extreme nature of the environment concerned, it is to be expected that the diversity of conditions and phenomena encountered in permafrost exceed what has previously been described and investigated. We further argue that climate change in concert with increasing development will bring about diverse permafrost-related impacts on vegetation, water quality, geohazards, and livelihoods. To better anticipate and mitigate these effects, a deepened understanding of high-elevation permafrost in subtropical latitudes as well as the pathways interconnecting environmental changes and human livelihoods are needed.

  18. Permafrost: occurrence and physiochemical processes

    International Nuclear Information System (INIS)

    Ahonen, L.

    2001-10-01

    Bedrock of the Northern Hemisphere areas to the north of about the 60th latitude are nowadays dominated by permafrost conditions. Fennoscandia is a major exception being characterised by temperate climate. In studying deep geological disposal of long-living nuclear waste, long-term climatic changes have to be taken into account. One of the scenarios to be studied is the extension of the deep permafrost conditions to the disposal site. Quaternary climatic fluctuations and their possible reasons are discussed shortly. The author's conclusion is that future climatic changes cannot be undoubtedly derived from the past variations, mainly because of the current anthropogenic involvement and of the poorly known dynamics of the major climate-affecting factors like ocean currents, which cannot be treated in a deterministic way. In low-porosity crystalline rocks permafrost may propagate to the depth of about 500 metres in some thousands to ten thousands of years. On the other hand, the major effects of permafrost are related to the freezing of water in the pores. Water expands about 9 percent in freezing, and the increasing stress may lead to pressure melting of ice. Dissolved salts in water do not accommodate into the solid ice, but they form saline water or brine segregations having freezing point of even less than minus ten degrees. A front of saline water may develop beneath the frozen bedrock. Pockets of saline water may also occur in ice, and unfrozen adsorption water may occur on the grain boundaries. With respect to the radionuclide transport processes, permafrost as such is a barrier, while the unfrozen domains (taliks) beneath major lake and river systems are potential flow paths. (orig.)

  19. The effect of permafrost thaw on short- and long-term carbon accumulation in permafrost mires

    Science.gov (United States)

    Olid, Carolina; Klaminder, Jonatan; Monteux, Sylvain; Johansson, Margareta; Dorrepaal, Ellen

    2017-04-01

    validate these hypotheses, an empirically based peat development model was applied to peat cores collected from manipulated thaw (n=6) and control (n=6) plots. Short- (decades) and long-(centuries) term C accumulation rates were estimated using a combined 210Pb and 14C chronology. In contrast to previous studies, our approach is long term and allows applying an empirical mass balance to evaluate depth-explicit changes in C inputs, C losses, and net C accumulation rates in response to permafrost thaw. Comparing shallow versus deep soil C does not only reflect short versus long-term C dynamics but also shows how the responses vary depending on different soil conditions. Our goal is to provide insights to better understand permafrost C dynamics to improve theoretical and predictive climate impact models.

  20. Permafrost Meta-Omics and Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Mackelprang, Rachel; Saleska, Scott R.; Jacobsen, Carsten Suhr; Jansson, Janet K.; Taş, Neslihan

    2016-06-29

    Permafrost (i.e., soil that has been frozen for at least 2 consecutive years) represents a habitat for microbial life at subzero temperatures (Gilichinsky et al. 2008). Approximately one quarter of the Earth’s surface is underlain by permafrost, which contains 25-50% of the total global soil carbon pool (Schuur et al. 2008, Tarnocai et al. 2009). This carbon is largely protected from microbial decomposition by reduced microbial activity in frozen conditions, but climate change is threatening to induce large-scale permafrost thaw thus exposing it to degradation. The resulting emissions of greenhouse gasses (GHGs) can produce a positive feedback loop and significantly amplify the effects of global warming. Increasing temperatures at high latitudes, changes in precipitation patterns, and frequent fire events have already initiated a widespread degradation of permafrost (Schuur et al. 2015).

  1. Study of transitory forms of carotenoids

    International Nuclear Information System (INIS)

    Mathis, Paul

    1970-01-01

    In order to explain the biological role of the carotenoids their transitory forms were studied with an apparatus measuring the small (∼10 -3 ) short-lived (100 ns to 1 ms) optical density variations obtained by excitation with a ruby laser. Two forms were studied: a) Triplet state 3 Car. - This state (t 1/2 ∼6 μs) is obtained not by direct excitation but by T-T energy transfer from chlorophyll, in different media (chloroplasts, pigments in solution or in micelle). Two arguments can be advanced to explain in terms of triplet energy transfer an essential biological role of carotenoids, protection against photodynamic effects: - the energy level of 3 Car is lower than that of the singlet of oxygen; - in vivo the T-T transfer from chlorophyll to the carotenoids is very fast: 30 ns.. b) Radical cation Car + . - This form is obtained by electron transfer from carotene to the triplet of Toluidine Blue, in ethanol. Car + (t 1/2 ∼200 μs) shows a strong absorption band at 910 nm. The properties of Car + are discussed in relation to other polyene derivatives and to hydrocarbon ions. Car + could be involved in certain biological electron transfers. (author) [fr

  2. Getting the parking right for transit-oriented development.

    Science.gov (United States)

    2012-03-01

    Increasingly MPOs in Texas are incorporating Transit-Oriented Development (TOD) or similar : concepts into their long-range plans for the purpose of achieving sustainable transportation. : One major challenge to implementing these TOD-type strategies...

  3. Consumption Responses to Permanent and Transitory Shocks to House Appreciation

    Science.gov (United States)

    2009-12-01

    food consumption alone is not a good measure of consumption to estimate its responses to changes in income or other behavioral parameters. We follow...Working Paper Series Congressional Budget Office Washington, D.C. Consumption Responses to Permanent and Transitory Shocks to House Appreciation Juan...to 00-00-2009 4. TITLE AND SUBTITLE Consumption Responses to Permanent and Transitory Shocks to House Appreciation 5a. CONTRACT NUMBER 5b. GRANT

  4. Effects of long-term simulated martian conditions on a freeze-dried and homogenized bacterial permafrost community

    DEFF Research Database (Denmark)

    Hansen, Aviaja Anna; Jensen, Lars Liengård; Kristoffersen, Tommy

    2009-01-01

    , while the number of viable cells was reduced in the upper 15 mm. The number of cultured aerobic bacteria was reduced in the upper 6 mm of the soil core, whereas the community structure of cultured anaerobic bacteria was relatively unaffected by the exposure conditions. As explanations for the observed...... and polynucleotides are more resistant to destruction than living biota....

  5. Thermal conditions of rock slopes below unstable infrastructure in Alpine permafrost area: the cases of the Cosmiques hut and the Grands Montets cable-car station (Mont Blanc massif)

    Science.gov (United States)

    Duvillard, Pierre-Allain; Magnin, Florence; Mörtl, Christian; Ravanel, Ludovic; Deline, Philip

    2017-04-01

    Thermal state of steep permafrost-affected rock faces is crucial to assess the safety and reliability of mountain infrastructure as current permafrost degradation affects the rock slope stability. In the Mont-Blanc massif, 23 infrastructures are built on such a rock face with 13 of them that are characterized by a high risk of destabilization (Duvillard et al., 2015), including the upper station of the Grands Montets cable car (3325 m a.s.l.) as well as the Cosmiques hut (3613 m a.s.l.) on which we will focus. These two buildings have already been affected by different geomorphological processes. A rockfall event (600 m3) occurred for example on the SE face on the Arête inférieure des Cosmiques on the 21st of August 1998 (Ravanel et al., 2013) and the Grands Montets case shows a slow subsidence of the stairway over the last decade. In order to better assess the role of the permafrost in these processes and to gain insight on possible future geomorphic activity, we characterized the current permafrost conditions and simulated its changes up to the end of the 21st century using two complementary approaches: (i) the result of ERT (Electrical Resistivity Tomography) surveys carried out in October 2016 on the northern and southern faces right below the Cosmiques hut (at the level of the foundations) and at the Aiguilles des Grands Montets; (ii) the modeling of mean annual rock surface temperature for 2016 and at the end of the 21st century (Magnin et al., in rev.). Duvillard P.-A., Ravanel L., Deline P. (2015). Risk assessment of infrastructure destabilisation due to global warming in the high French Alps. Journal of Alpine Research, 103 (2). Magnin F., Josnin J.-Y., Ravanel L., Pergaud J., Pohl B., Deline P. (in rev.). Modelling rock wall permafrost degradation in the Mont Blanc massif from the LIA to the end of the 21st century. The Cryosphere Discuss., doi:10.5194/tc-2016-132. Ravanel L., Deline P., Lambiel C. and Vincent C. (2013). Instability of a high alpine

  6. Permafrost and urban Development in Norilsk Russia.

    Science.gov (United States)

    Shiklomanov, N. I.; Streletskiy, D. A.; Grebenets, V. I.

    2017-12-01

    The city of Norilsk was established in 1935 as a GULAG mining and metallurgy work camp to explore the rich deposits of non-ferrous metals. By the 1989, the population of Norilsk reached 179,757 people. Two additional cities were developed in proximity to Norilsk in the 1960s-1980s: Talnakh (1989 population 65,710); and Kaerkan (1989 population 29,824) making the Norilsk region a major Arctic metropolis. While such rapid growth is not unusual for developing industrial cities, the geographic location makes Norilsk rather unique among world urban centers. It was built in Central Siberia at 69°51' N latitude (above the Arctic Circle), in region characterized by harsh subarctic climate (mean annual temperature around -10 oC), over forest tundra/tundra transitional landscapes underlined by perennially frozen ground (permafrost). Throughout its existence, the Norilsk region was highly isolated: it is not connected to Russian road and railroad systems. The harsh environmental conditions provided significant and rather unique challenges to Norilsk development. Specifically, the presence of ice-rich permafrost imposed restrictions on application of standard urban planning and engineering practices. This presentation analyzes the history of permafrost construction in Norilsk. It shows how though initial trial and errors, a set of guiding principles and engineering methods of construction on permafrost were developed allowing a rapid urbanization of the area during the 1960-1980s. However, despite significant advances in permafrost engineering, the pronounced permafrost degradation has become evident in Norilsk by the mid 1980s and has accelerated rapidly since the mid 1990s resulting in widespread deformation of buildings. Climatic changes are frequently identified as a major cause of accelerated deterioration of infrastructure build on permafrost. However, we argue that other factors, including the complexity of interactions between deferent components of urban

  7. Evidence for nonuniform permafrost degradation after fire in boreal landscapes

    Science.gov (United States)

    Minsley, Burke J.; Pastick, Neal J.; Wylie, Bruce K.; Brown, Dana R.N.; Kass, M. Andy

    2016-01-01

    Fire can be a significant driver of permafrost change in boreal landscapes, altering the availability of soil carbon and nutrients that have important implications for future climate and ecological succession. However, not all landscapes are equally susceptible to fire-induced change. As fire frequency is expected to increase in the high latitudes, methods to understand the vulnerability and resilience of different landscapes to permafrost degradation are needed. We present a combination of multiscale remote sensing, geophysical, and field observations that reveal details of both near-surface (1 m) impacts of fire on permafrost. Along 11 transects that span burned-unburned boundaries in different landscape settings within interior Alaska, subsurface electrical resistivity and nuclear magnetic resonance data indicate locations where permafrost appears to be resilient to disturbance from fire, areas where warm permafrost conditions exist that may be most vulnerable to future change, and also areas where permafrost has thawed. High-resolution geophysical data corroborate remote sensing interpretations of near-surface permafrost and also add new high-fidelity details of spatial heterogeneity that extend from the shallow subsurface to depths of about 10 m. Results show that postfire impacts on permafrost can be variable and depend on multiple factors such as fire severity, soil texture, soil moisture, and time since fire.

  8. The microbial ecology of permafrost

    DEFF Research Database (Denmark)

    Jansson, Janet; Tas, Neslihan

    2014-01-01

    Permafrost constitutes a major portion of the terrestrial cryosphere of the Earth and is a unique ecological niche for cold-adapted microorganisms. There is a relatively high microbial diversity in permafrost, although there is some variation in community composition across different permafrost......-gas emissions. This Review describes new data on the microbial ecology of permafrost and provides a platform for understanding microbial life strategies in frozen soil as well as the impact of climate change on permafrost microorganisms and their functional roles....

  9. Lumbricidae as transitory hosts in Metastrongylus infection in swine

    Directory of Open Access Journals (Sweden)

    Pavlović Ivan

    2005-01-01

    Full Text Available Metastrongylidosis or lungworm disease in swine is a disease caused by several types of nematodes of the genus Metastrongylus. Metastrongylidae are biohelminths whose causes use transitory hosts for their development and maintaining their biological cycle, and in this case they are numerous species of Lumbricidae (earthworms. Depending on the geographic environment, numerous representatives of Lumbricidae persist as transitory hosts. In our environment, these are dominant earthworm species of the genus Eisenia spp, Dandreobena spp, Allopbophora spp, Lubricus spp, Octoiasium spp, Bimastus spp, and rarely those from the genus Heledrillus spp. Swine are infected perorally with Metastrongylidae when they ingest infected earthworms.

  10. Compositional diversity of near-, far-side transitory zone around ...

    Indian Academy of Sciences (India)

    Compositional diversity of near-, far-side transitory zone of the lunar surface. 235 with diagnostic absorption features at .... satisfy the positivity and sum-to-unity constraints, as Legendre coefficients β and γ. RMSE = √ ..... JPL Publication) 96 4(1) 9–11. Chang C I, Wu C, Liu W and Ouyang Y 2006 A new growing method for ...

  11. Gas hydrates and permafrost in continental northern West Siberia; Gashydrate und Permafrost im kontinentalen noerdlichen Westsibirien

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, B. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany); Braun, A.; Poelchau, H.S. [Forschungszentrum Juelich (Germany). Inst. fuer Erdoel und Organische Geochemie; Littke, R. [RWTH Aachen (Germany). Lehrstuhl fuer Geologie, Geochemie und Lagerstaetten des Erdoels und der Kohle

    1997-12-31

    The largest natural gas pool in the world is located in northern part of the West Siberian Basin. During the Quaternary this reservoir became overlaid with several hundreds of metres of permafrost. The pressure and temperature conditions prevailing under this permafrost zone have led to the development of gas hydrates. As far as is known today there is no genetic relationship between the formation of the gas pool and the development of gas hydrates. The present contribution deals with these questions in detail. (MSK) [Deutsch] Im Nordteil des westsibirischen Beckens liegt die groesste Erdgaslagerstaette der Erde. Darueber hat sich im Quartaer ein mehrere hundert Meter maechtiger Permafrost gebildet. Die unter der Premafrostzone herrschenden Druck-und Temperaturbedingungen ermoeglichten die Bildung von Gashydraten. Nach heutigen Erkenntnisse besteht kein genetischer Zusammenhang zwischen Lagerstaettenbildung und Gashydraten. Im Folgenden werden Einzelheiten geschildert.

  12. Cryopegs as destabilization factor of intra-permafrost gas hydrates

    Science.gov (United States)

    Chuvilin, Evgeny; Bukhanov, Boris; Istomin, Vladimir

    2016-04-01

    A characteristic feature of permafrost soils in the Arctic is widespread intra-permafrost unfrozen brine lenses - cryopegs. They are often found in permafrost horizons in the north part of Western Siberia, in particular, on the Yamal Peninsula. Cryopegs depths in permafrost zone can be tens and hundreds of meters from the top of frozen strata. The chemical composition of natural cryopegs is close to sea waters, but is characterized by high mineralization. They have a sodium-chloride primary composition with a minor amount of sulphate. Mineralization of cryopegs brine is often hundreds of grams per liter, and the temperature is around -6…-8 °C. The formation of cryopegs in permafrost is associated with processes of long-term freezing of sediments and cryogenic concentration of salts and salt solutions in local areas. The cryopegs' formation can take place in the course of permafrost evolution at the sea transgressions and regressions during freezing of saline sea sediments. Very important feature of cryopegs in permafrost is their transformation in the process of changing temperature and pressure conditions. As a result, the salinity and chemical composition are changed and in addition the cryopegs' location can be changed during their migration. The cryopegs migration violates the thermodynamic conditions of existence intra-permafrost gas hydrate formations, especially the relic gas hydrates deposits, which are situated in the shallow permafrost up to 100 meters depth in a metastable state [1]. The interaction cryopegs with gas hydrates accumulations can cause decomposition of intra-permafrost hydrates. Moreover, the increasing of salt and unfrozen water content in sedimentary rocks sharply reduce the efficiency of gas hydrates self-preservation in frozen soils. It is confirmed by experimental investigations of interaction of frozen gas hydrate bearing sediments with salt solutions [2]. So, horizons with elevated pressure can appear, as a result of gas hydrate

  13. The long-term fate of permafrost peatlands under rapid climate warming

    DEFF Research Database (Denmark)

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon...... stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological...... approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed...

  14. Participatory design in transit-oriented development uncovers social benefits

    OpenAIRE

    Fernandez Milan, Blanca; Creutzig, Felix

    2016-01-01

    Transit-oriented development (TOD) tackles multiple challenges simultaneously and fosters sustainable urban development. Low-carbon intensity transport modes help mitigating climate change, enhance the quality of local ecosystems and offer monetary savings. While less well studied, TOD also positively affects citizen’s social interactions. The social sustainability that can be drawn from TOD interventions may multiply when designed through participatory planning processes. To investigate this...

  15. Wind-driven snow conditions control the occurrence of contemporary marginal mountain permafrost in the Chic-Choc Mountains, south-eastern Canada: a case study from Mont Jacques-Cartier

    Directory of Open Access Journals (Sweden)

    G. Davesne

    2017-06-01

    Full Text Available We present data on the distribution and thermophysical properties of snow collected sporadically over 4 decades along with recent data of ground surface temperature from Mont Jacques-Cartier (1268 m a.s.l., the highest summit in the Appalachians of south-eastern Canada. We demonstrate that the occurrence of contemporary permafrost is necessarily associated with a very thin and wind-packed winter snow cover which brings local azonal topo-climatic conditions on the dome-shaped summit. The aims of this study were (i to understand the snow distribution pattern and snow thermophysical properties on the Mont Jacques-Cartier summit and (ii to investigate the impact of snow on the spatial distribution of the ground surface temperature (GST using temperature sensors deployed over the summit. Results showed that above the local treeline, the summit is characterized by a snow cover typically less than 30 cm thick which is explained by the strong westerly winds interacting with the local surface roughness created by the physiography and surficial geomorphology of the site. The snowpack structure is fairly similar to that observed on windy Arctic tundra with a top dense wind slab (300 to 450 kg m−3 of high thermal conductivity, which facilitates heat transfer between the ground surface and the atmosphere. The mean annual ground surface temperature (MAGST below this thin and wind-packed snow cover was about −1 °C in 2013 and 2014, for the higher, exposed, blockfield-covered sector of the summit characterized by a sporadic herbaceous cover. In contrast, for the gentle slopes covered with stunted spruce (krummholz, and for the steep leeward slope to the south-east of the summit, the MAGST was around 3 °C in 2013 and 2014. The study concludes that the permafrost on Mont Jacques-Cartier, most widely in the Chic-Choc Mountains and by extension in the southern highest summits of the Appalachians, is therefore likely limited to the barren wind

  16. Transitory Control of Unsteady Separation using Pulsed Actuation

    International Nuclear Information System (INIS)

    Woo, George T K; Glezer, Ari

    2011-01-01

    The dynamic mechanisms of transitory flow attachment effected by pulsed actuation of the separated flow over a stalled airfoil are investigated experimentally. Actuation is effected by momentary pulsed jets generated by a spanwise array of combustion-based actuators such that the characteristic time of jet duration is nominally an order of magnitude shorter than the flow's convective time scale. The transitory flow field in the cross stream plane above the airfoil and in its near wake is investigated using multiple high-resolution PIV images that are obtained phase-locked to the actuation for continuous tracking of vorticity concentrations. The brief actuation pulse leads to severing of the separated vorticity layer and the subsequent shedding of large-scale vortical structures owing to the collapse of the separated flow domain which is accompanied by strong changes in the circulation about the entire airfoil. By exploiting the disparity between the characteristic times of flow response to actuation and relaxation, it is shown that successive actuation pulses can extend the flow attachment and enhance the global aerodynamic performance. It is also shown that coupling of the actuation to the airfoil's motion during cyclical pitch enhances the effect of transitory flow control and leads to a significant suppression of dynamic stall.

  17. Computing a ground appropriateness index for route selection in permafrost regions

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2017-10-01

    Full Text Available The reasonable calculation of ground appropriateness index in permafrost region is the precondition of highway route design in permafrost region. The theory of knowledge base and fuzzy mathematics are applied, and the damage effect of permafrost is considered in the paper. Based on the idea of protecting permafrost the calculation method of ground appropriateness index is put forward. Firstly, based on the actual environment conditions, the paper determines the factors affecting the road layout in permafrost areas by qualitative and quantitative analysis, including the annual slope, the average annual ground temperature of permafrost, the amount of ice in frozen soil, and the interference engineering. Secondly, based on the knowledge base theory and the use of Delphi method, the paper establishes the knowledge base, the rule base of the permafrost region and inference mechanism. The method of selecting the road in permafrost region is completed and realized by using the software platform. Thirdly, taking the Tuotuo River to Kaixin Mountain section of permafrost region as an example, the application of the method is studied by using an ArcGIS platform. Results show that the route plan determined by the method of selecting the road in permafrost region can avoid the high temperature and high ice content area, conform the terrain changes and evade the heat disturbance among the existing projects. A reasonable route plan can be achieved, and it can provide the basis for the next engineering construction.

  18. High risk of permafrost thaw

    Science.gov (United States)

    E.A.G. Schuur; B.W. Abbott; W.B. Bowden; V. Brovkin; P. Camill; J.P. Canadell; F.S. Chapin; T.R. Christensen; J.P. Chanton; P. Ciais; P.M. Crill; B.T. Crosby; C.I. Czimczik; G. Grosse; D.J. Hayes; G. Hugelius; J.D. Jastrow; T. Kleinen; C.D. Koven; G. Krinner; P. Kuhry; D.M. Lawrence; S.M. Natali; C.L. Ping; A. Rinke; W.J. Riley; V.E. Romanovsky; A.B.K. Sannel; C. Schadel; K. Schaefer; Z.M. Subin; C. Tarnocai; M. Turetsky; K. M. Walter-Anthony; C.J. Wilson; S.A. Zimov

    2011-01-01

    Arctic temperatures are rising fast, and permafrost is thawing. Carbon released into the atmosphere from permafrost soils will accelerate climate change, but the magnitude of this effect remains highly uncertain. Our collective estimate is that carbon will be released more quickly than models suggest, and at levels that are cause for serious concern. We calculate that...

  19. DIAGNOSIS AND THERAPY IN TRANSITORY MYOCARDIAL ISCHEMIA

    Directory of Open Access Journals (Sweden)

    Anica Pavlovic

    2008-01-01

    Full Text Available Cardiac dysfunction occurring within subarachnoid hemorrhage named neurogenic stunned myocardium have great impact on intensive care of patients with SAH. Timely diagnosis and treatment of such condition can provide better haemodynamics of damaged brain. The standard follow-up was performed in 30 patients with SAH during two years at the Clinic of Neurosurgery (2005,2006. Serial electrocardiography, echocardiography, as well as laboratory findings of special biomarkers of left ventricular wall motion abnormalities were performed. All patients were treated with Urapidil, Metoprolol, MgSO4 by cheme and ACE inhibitors. Ninety EKG were analyzed in the study, as well as 16 electrocardiographies. The highest levels of CPK, CK-MB and TnI before and after the therapy were also recoded. EKG showed the signs of ischemia in 9 of 30 patients on 1st day and 7 of 30 patients on 3rd day of the therapy. The highest level of CK-MB was present during the 1st day with mean value of 67,80±1,83 IU/L that decreased on 3rd day of therapy with mean value of 66,8±1,83 IU/L, TnI was positive in 16 cases. It showed statistically significant decrease from 0,29 ng/ml till 0,187 ng/ml and p < 0,01. Myocardial ischaemia has been proven to be a very significant complication in SAH. Appropriate treatment of myocardial ischaemia seems to improve systemic haemodynamics, as well as haemodynamics of the damaged brain.

  20. NORPERM, the Norwegian Permafrost Database - a TSP NORWAY IPY legacy

    Science.gov (United States)

    Juliussen, H.; Christiansen, H. H.; Strand, G. S.; Iversen, S.; Midttømme, K.; Rønning, J. S.

    2010-10-01

    NORPERM, the Norwegian Permafrost Database, was developed at the Geological Survey of Norway during the International Polar Year (IPY) 2007-2009 as the main data legacy of the IPY research project Permafrost Observatory Project: A Contribution to the Thermal State of Permafrost in Norway and Svalbard (TSP NORWAY). Its structural and technical design is described in this paper along with the ground temperature data infrastructure in Norway and Svalbard, focussing on the TSP NORWAY permafrost observatory installations in the North Scandinavian Permafrost Observatory and Nordenskiöld Land Permafrost Observatory, being the primary data providers of NORPERM. Further developments of the database, possibly towards a regional database for the Nordic area, are also discussed. The purpose of NORPERM is to store ground temperature data safely and in a standard format for use in future research. The IPY data policy of open, free, full and timely release of IPY data is followed, and the borehole metadata description follows the Global Terrestrial Network for Permafrost (GTN-P) standard. NORPERM is purely a temperature database, and the data is stored in a relation database management system and made publically available online through a map-based graphical user interface. The datasets include temperature time series from various depths in boreholes and from the air, snow cover, ground-surface or upper ground layer recorded by miniature temperature data-loggers, and temperature profiles with depth in boreholes obtained by occasional manual logging. All the temperature data from the TSP NORWAY research project is included in the database, totalling 32 temperature time series from boreholes, 98 time series of micrometeorological temperature conditions, and 6 temperature depth profiles obtained by manual logging in boreholes. The database content will gradually increase as data from previous and future projects are added. Links to near real-time permafrost temperatures, obtained

  1. In situ nuclear magnetic response of permafrost and active layer soil in boreal and tundra ecosystems

    DEFF Research Database (Denmark)

    Kass, Mason Andrew; Irons, Trevor; Minsley, Burke J.

    2017-01-01

    of the nuclear magnetic resonance (NMR) response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show......Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience...

  2. In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

    Science.gov (United States)

    Kass, M. Andy; Irons, Trevor P.; Minsley, Burke J.; Pastick, Neal J.; Brown, Dana R. N.; Wylie, Bruce K.

    2017-12-01

    Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multiyear investigation into the impacts of wildfires on permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR) response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show the efficacy of borehole NMR (bNMR) to permafrost studies. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR is sensitive to the nucleation of ice within soil pore spaces.

  3. In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

    Directory of Open Access Journals (Sweden)

    M. A. Kass

    2017-12-01

    Full Text Available Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multiyear investigation into the impacts of wildfires on permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show the efficacy of borehole NMR (bNMR to permafrost studies. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR is sensitive to the nucleation of ice within soil pore spaces.

  4. The duration of the transitory period of public gas distribution

    International Nuclear Information System (INIS)

    Gazzola, D.

    2006-01-01

    The article describes the interpretative problems concerning the duration of the transitory period of public gas distribution after law decree 273/05 came into effect. This decree is the third legislative measure which, in a period of five years, reforms the transitory provisions. The article outlines the normative background of legislative decree n. 164/00 (so called Letta decree) and law n. 239/04 (so called Marzano law) and it analyses their judicial interpretations. It then explains the changes introduced by law decree n. 273/05 and the new interpretative problems there might be with reference to this decree. The decree clarifies the due date of the transitory period and specifies that the date of 31st December 2005 is postponed to 31st December 2007. The Administrative Tribunal of Lombardia Region Brescia tried to limit the effects of law decree n. 273/05, stating that the new expiration date could not regard the contracts for which the local authorities had already acknowledged the previous due date. The State Council argued instead that the new law decree regards all the contracts. This decree also clarifies that the chances of increasing duration ex art. 15, comma 7, legislative decree n. 164/00, applies automatically, but it doesn't solve the interpretative problem concerning the possibility of adding up more than one of these chances. The article focuses on the problems of the public gas distribution after the reform of this sector with the implementation of directive n. 98/30/CE and it underlines that the various legislative measures of these years are indicative of the difficulty to allow a gradual transition towards a liberalized market. In this context, law decree n. 273/05 is the last legislative measure which tries to guarantee a balance between the rapid liberalization of the market, on one hand, and the interests of the firms which had contracts when the reform came into effect, on the other hand [it

  5. Methane production as key to the greenhouse gas budget of thawing permafrost

    Science.gov (United States)

    Knoblauch, Christian; Beer, Christian; Liebner, Susanne; Grigoriev, Mikhail N.; Pfeiffer, Eva-Maria

    2018-04-01

    Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change1,2. Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils3-6 and a stronger permafrost carbon-climate feedback from drained (oxic) soils1,7. Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2-carbon equivalents (CO2-Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account8. A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 ± 58 g CO2-C kgC-1 (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2-Ce (241 ± 138 g CO2-Ce kgC-1) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.

  6. Collaboration in Education: International Field Class on Permafrost

    Science.gov (United States)

    Streletskiy, D. A.; Shiklomanov, N. I.; Grebenets, V. I.

    2011-12-01

    Field work is a dominant research component in the earth sciences. Understanding and proper use of field methods can enhance the quality of research, while lack of understanding in acquiring data can lead to misleading interpretation of results. Early involvement in field work helps students to bridge the gap between theoretical knowledge and practical applications and to be better prepared for future jobs. However, many University curriculums lack adequate, required field methods courses. Presented are results of collaboration between the George Washington and Moscow State Universities in organization of field courses on Arctic physical and social environments. The latest field course took place in summer 2011 in the Central Siberian region and is a part of the International Permafrost Association education and outreach effort initiated during International Polar Year. The 25 day course involved fifteen Russian and US students who traveled from Moscow to Krasnoyarsk, and then along Yenisey river to Norilsk. This route was chosen as having diversity of natural conditions and variety of economic, engineering, and demographic problems associated with development. The main goal of the class was to investigate permafrost conditions of Central Siberia; dynamics of upper permafrost due to changing climate and under anthropogenic influence; and to understand factors responsible for the diversity of permafrost conditions in the region. The students and instructors were required to make presentations on a variety of topics focusing on the region or research methods, such as climate, vegetation, hydrology, history of development, economics, remote sensing, etc. The emphasis in the field was made on understanding permafrost in relation to other components of the natural system. For example, landscape conditions (including microclimatic, biogeographic and pedologic conditions) were described at every site located in natural settings. Sites located in settlements were evaluated

  7. The Ecological Situation in the Russian Arctic Permafrost Zone

    Directory of Open Access Journals (Sweden)

    Petrov Sergei

    2016-01-01

    Full Text Available The paper describes innovative approaches to ensure environmental safety in the production of hydrocarbon material in a permafrost zone. Studies the anthropogenic environmental factors, climatic and geographical and geological conditions of Purovskiy district of Yamalo-Nenets Autonomous Area (YaNAO. We consider the chemical characteristics of wastewater discharged into surface water objects, polluting emissions into the atmosphere. The conclusions of the environmental situation in Purovskiy and Ustpurovsk-Tazovskiy permafrost areas. Calculate the concentration of pollutants in the control section of the water object and the maximum ground-level concentrations of pollutants in the atmospheric air. The conclusions about the exceeding the maximum permissible concentration (MPC in the atmospheric air for solids, carbon monoxide, nitrogen dioxide. Was examined the climatic conditions of the Far North. Correlational analysis was performed between human factors and temperature conditions of the northern territories, as well as between the climate and natural features cryological and disturbed permafrost soils.

  8. Multidimensional epistasis and the transitory advantage of sex.

    Directory of Open Access Journals (Sweden)

    Stefan Nowak

    2014-09-01

    Full Text Available Identifying and quantifying the benefits of sex and recombination is a long-standing problem in evolutionary theory. In particular, contradictory claims have been made about the existence of a benefit of recombination on high dimensional fitness landscapes in the presence of sign epistasis. Here we present a comparative numerical study of sexual and asexual evolutionary dynamics of haploids on tunably rugged model landscapes under strong selection, paying special attention to the temporal development of the evolutionary advantage of recombination and the link between population diversity and the rate of adaptation. We show that the adaptive advantage of recombination on static rugged landscapes is strictly transitory. At early times, an advantage of recombination arises through the possibility to combine individually occurring beneficial mutations, but this effect is reversed at longer times by the much more efficient trapping of recombining populations at local fitness peaks. These findings are explained by means of well-established results for a setup with only two loci. In accordance with the Red Queen hypothesis the transitory advantage can be prolonged indefinitely in fluctuating environments, and it is maximal when the environment fluctuates on the same time scale on which trapping at local optima typically occurs.

  9. Mapping permafrost with airborne electromagnetics

    Science.gov (United States)

    Minsley, B. J.; Ball, L. B.; Bloss, B. R.; Kass, A.; Pastick, N.; Smith, B. D.; Voss, C. I.; Walsh, D. O.; Walvoord, M. A.; Wylie, B. K.

    2014-12-01

    Permafrost is a key characteristic of cold region landscapes, yet detailed assessments of how the subsurface distribution of permafrost impacts the environment, hydrologic systems, and infrastructure are lacking. Data acquired from several airborne electromagnetic (AEM) surveys in Alaska provide significant new insight into the spatial extent of permafrost over larger areas (hundreds to thousands of square kilometers) than can be mapped using ground-based geophysical methods or through drilling. We compare several AEM datasets from different areas of interior Alaska, and explore the capacity of these data to infer geologic structure, permafrost extent, and related hydrologic processes. We also assess the impact of fires on permafrost by comparing data from different burn years within similar geological environments. Ultimately, interpretations rely on understanding the relationship between electrical resistivity measured by AEM surveys and the physical properties of interest such as geology, permafrost, and unfrozen water content in the subsurface. These relationships are often ambiguous and non-unique, so additional information is useful for reducing uncertainty. Shallow (upper ~1m) permafrost and soil characteristics identified from remotely sensed imagery and field observations help to constrain and aerially extend near-surface AEM interpretations, where correlations between the AEM and remote sensing data are identified using empirical multivariate analyses. Surface nuclear magnetic resonance (sNMR) measurements quantify the contribution of unfrozen water at depth to the AEM-derived electrical resistivity models at several locations within one survey area. AEM surveys fill a critical data gap in the subsurface characterization of permafrost environments and will be valuable in future mapping and monitoring programs in cold regions.

  10. Probabilistic modeling of climate change impacts in permafrost regions

    Science.gov (United States)

    Anisimov, O.

    2009-04-01

    The new type of climate impact models has recently come into existence. Unlike conventional models, they take into account the probabilistic nature of climatic projections and small-scale spatial variability of permafrost parameters. In this study we describe the new stochastic permafrost modeling methodology and present the predictive results obtained for the Northern Eurasia under the ensemble climatic projection for the mid-21st century. Changes in permafrost are very illustrative of the impacts of global warming. It underlies about 22.8 million square km or 24% of the land area in the Northern Hemisphere and largely controls the state of the environment and socio-economical development in the northern lands. Observed and projected for the future warming is more pronounced in high latitudes, and there are indications that climatic change has already affected permafrost leading to deeper seasonal thawing and disappearance of the frozen ground in many locations. Particular concerns are associated with environmental and economical risks due to the damage of constructions, and with potential enhancement of the global warming through emission of greenhouse gases from thawing permafrost. Comprehensive permafrost projections are needed to predict such processes. We developed new type of stochastic model, which operates with the probability distribution functions of the parameters characterizing the state of permafrost. Air temperature, precipitation, snow depth, as well as vegetation and soil properties contribute to the variability of these parameters in space and over time, which is taken into account in the calculations of the statistical ensemble representing potential states of permafrost under the prescribed conditions. The model requires appropriate climatic and environmental data characterizing baseline or projected for the future conditions. Four gridded sets of climatic parameters constructed through spatial interpolation of meteorological observations and

  11. Using Modeling Tools to Better Understand Permafrost Hydrology

    Directory of Open Access Journals (Sweden)

    Clément Fabre

    2017-06-01

    Full Text Available Modification of the hydrological cycle and, subsequently, of other global cycles is expected in Arctic watersheds owing to global change. Future climate scenarios imply widespread permafrost degradation caused by an increase in air temperature, and the expected effect on permafrost hydrology is immense. This study aims at analyzing, and quantifying the daily water transfer in the largest Arctic river system, the Yenisei River in central Siberia, Russia, partially underlain by permafrost. The semi-distributed SWAT (Soil and Water Assessment Tool hydrological model has been calibrated and validated at a daily time step in historical discharge simulations for the 2003–2014 period. The model parameters have been adjusted to embrace the hydrological features of permafrost. SWAT is shown capable to estimate water fluxes at a daily time step, especially during unfrozen periods, once are considered specific climatic and soils conditions adapted to a permafrost watershed. The model simulates average annual contribution to runoff of 263 millimeters per year (mm yr−1 distributed as 152 mm yr−1 (58% of surface runoff, 103 mm yr−1 (39% of lateral flow and 8 mm yr−1 (3% of return flow from the aquifer. These results are integrated on a reduced basin area downstream from large dams and are closer to observations than previous modeling exercises.

  12. CRYOLINK: Monitoring of permafrost and seasonal frost in southern Norway

    Science.gov (United States)

    Farbrot, Herman; Hipp, Tobias; Etzelmüller, Bernd; Humlum, Ole; Isaksen, Ketil; Strand Ødegârd, Rune

    2010-05-01

    The modern southern boundary for Scandinavian permafrost is located in the mountains of Southern Norway. Permafrost and seasonal frost are considered key components of the cryosphere, and the climate-permafrost relation has acquired added importance with the increasing awareness and concern of rising air temperatures. The three-year research project CRYOLINK ("Permafrost and seasonal frost in southern Norway") aims at improving knowledge on past and present ground temperatures, seasonal frost, and distribution of mountain permafrost in Southern Norway by addressing the fundamental problem of heat transfer between the atmosphere and the ground surface. Hence, several shallow boreholes have been drilled in August 2008 in three areas (Juvvass, Jetta and Tron) situated along a west-east transect. On most borehole sites air and ground temperatures are measured. Further, vertical arrays of Miniature Temperature Dataloggers (MTDs; Thermochron iBottons®) at fixed heights above the ground surface have been installed to roughly determine the snow depths at the sites, which is also indicated by digital cameras providing daily pictures of snow and weather conditions. In addition individual MTDs have been placed out to measure ground surface temperature at different aspects and snow settings. This presentation will focus on the field set up and give examples of data obtained from the sites.

  13. Circumpolar Active-Layer Permafrost System (CAPS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Circumpolar Active-Layer Permafrost System (CAPS) contains over 100 data sets pertaining to permafrost and frozen ground topics. It also contains detailed...

  14. Transient thermal effects in Alpine permafrost

    Directory of Open Access Journals (Sweden)

    J. Noetzli

    2009-04-01

    Full Text Available In high mountain areas, permafrost is important because it influences the occurrence of natural hazards, because it has to be considered in construction practices, and because it is sensitive to climate change. The assessment of its distribution and evolution is challenging because of highly variable conditions at and below the surface, steep topography and varying climatic conditions. This paper presents a systematic investigation of effects of topography and climate variability that are important for subsurface temperatures in Alpine bedrock permafrost. We studied the effects of both, past and projected future ground surface temperature variations on the basis of numerical experimentation with simplified mountain topography in order to demonstrate the principal effects. The modeling approach applied combines a distributed surface energy balance model and a three-dimensional subsurface heat conduction scheme. Results show that the past climate variations that essentially influence present-day permafrost temperatures at depth of the idealized mountains are the last glacial period and the major fluctuations in the past millennium. Transient effects from projected future warming, however, are likely larger than those from past climate conditions because larger temperature changes at the surface occur in shorter time periods. We further demonstrate the accelerating influence of multi-lateral warming in steep and complex topography for a temperature signal entering the subsurface as compared to the situation in flat areas. The effects of varying and uncertain material properties (i.e., thermal properties, porosity, and freezing characteristics on the subsurface temperature field were examined in sensitivity studies. A considerable influence of latent heat due to water in low-porosity bedrock was only shown for simulations over time periods of decades to centuries. At the end, the model was applied to the topographic setting of the Matterhorn

  15. Permafrost dynamics structure species compositions of oribatid mite (Acari: Oribatida communities in sub-Arctic palsa mires

    Directory of Open Access Journals (Sweden)

    Inkeri Markkula

    2014-10-01

    Full Text Available Palsa mires are sub-Arctic peatland complexes, vulnerable ecosystems with patches of permafrost. Permafrost thawing in palsa mires occurs throughout Fennoscandia, probably due to local climatic warming. In palsa mires, permafrost thaw alters hydrological conditions, vegetation structure and microhabitat composition with unknown consequences for invertebrate fauna. This study's objectives were to examine the role of microhabitat heterogeneity and the effects of permafrost dynamics and thaw on oribatid mite communities in palsa mires. Oribatid mites were sampled in two palsa mires in Finland and Norway. Three different types of microhabitats were examined: graminoid-dominated wet sites, herb-dominated small hummocks and evergreen shrub-dominated permafrost-underlain palsa hummocks. The results indicate that permafrost dynamics are an important factor structuring oribatid mite communities in palsa mires. The community composition of oribatid mites differed remarkably among microhabitats. Six species were significantly more abundant in permafrost-underlain microhabitats in relation to non-permafrost microhabitats. None of the species identified occurred exclusively in permafrost-underlain microhabitats. Findings suggest that permafrost thaw may not have an impact on species diversity but may alter community composition of oribatid mites in palsa mire ecosystems.

  16. High risk of permafrost thaw

    Energy Technology Data Exchange (ETDEWEB)

    Schuur, E.A.G.; Abbott, B.; Koven, C.D,; Riley, W.J.; Subin, Z.M.; al, et

    2011-11-01

    In the Arctic, temperatures are rising fast, and permafrost is thawing. Carbon released to the atmosphere from permafrost soils could accelerate climate change, but the likely magnitude of this effect is still highly uncertain. A collective estimate made by a group of permafrost experts, including myself, is that carbon could be released more quickly than models currently suggest, and at levels that are cause for serious concern. While our models of carbon emission from permafrost thaw are lacking, experts intimately familiar with these landscapes and processes have accumulated knowledge about what they expect to happen, based on both quantitative data and qualitative understanding of these systems. We (the authors of this piece) attempted to quantify this expertise through a survey developed over several years, starting in 2009. Our survey asked experts what percentage of surface permafrost they thought was likely to thaw, how much carbon would be released, and how much of that would be methane, for three time periods and under four warming scenarios that are part of the new IPCC Fifth Assessment Report.

  17. Quantifying Permafrost Characteristics with DCR-ERT

    Science.gov (United States)

    Schnabel, W.; Trochim, E.; Munk, J.; Kanevskiy, M. Z.; Shur, Y.; Fortier, R.

    2012-12-01

    Geophysical methods are an efficient method for quantifying permafrost characteristics for Arctic road design and engineering. In the Alaskan Arctic construction and maintenance of roads requires integration of permafrost; ground that is below 0 degrees C for two or more years. Features such as ice content and temperature are critical for understanding current and future ground conditions for planning, design and evaluation of engineering applications. This study focused on the proposed Foothills West Transportation Access project corridor where the purpose is to construct a new all-season road connecting the Dalton Highway to Umiat. Four major areas were chosen that represented a range of conditions including gravel bars, alluvial plains, tussock tundra (both unburned and burned conditions), high and low centered ice-wedge polygons and an active thermokarst feature. Direct-current resistivity using galvanic contact (DCR-ERT) was applied over transects. In conjunction complimentary site data including boreholes, active layer depths, vegetation descriptions and site photographs was obtained. The boreholes provided information on soil morphology, ice texture and gravimetric moisture content. Horizontal and vertical resolutions in the DCR-ERT were varied to determine the presence or absence of ground ice; subsurface heterogeneity; and the depth to groundwater (if present). The four main DCR-ERT methods used were: 84 electrodes with 2 m spacing; 42 electrodes with 0.5 m spacing; 42 electrodes with 2 m spacing; and 84 electrodes with 1 m spacing. In terms of identifying the ground ice characteristics the higher horizontal resolution DCR-ERT transects with either 42 or 84 electrodes and 0.5 or 1 m spacing were best able to differentiate wedge-ice. This evaluation is based on a combination of both borehole stratigraphy and surface characteristics. Simulated apparent resistivity values for permafrost areas varied from a low of 4582 Ω m to a high of 10034 Ω m. Previous

  18. Permafrost collapse after shrub removal shifts tundra ecosystem to a methane source

    DEFF Research Database (Denmark)

    Nauta, Ake L.; Heijmans, Monique P.D.; Blok, Daan

    2015-01-01

    Arctic tundra ecosystems are warming almost twice as fast as the global average1. Permafrost thaw and the resulting release of greenhouse gases from decomposing soil organic carbon have the potential to accelerate climate warming2,3. In recent decades, Arctic tundra ecosystems have changed rapidly4......, including expansion of woody vegetation5,6, in response to changing climate conditions. How such vegetation changes contribute to stabilization or destabilization of the permafrost is unknown. Here we present six years of field observations in a shrub removal experiment at a Siberian tundra site. Removing...... experiment demonstrate the importance of the vegetation cover for protection of the massive carbon reservoirs stored in the permafrost and illustrate the strong vulnerability of these tundra ecosystems to perturbations. If permafrost thawing can more frequently trigger such local permafrost collapse, methane...

  19. Present and LGM permafrost from climate simulations: contribution of statistical downscaling

    Directory of Open Access Journals (Sweden)

    G. Levavasseur

    2011-11-01

    Full Text Available We quantify the agreement between permafrost distributions from PMIP2 (Paleoclimate Modeling Intercomparison Project climate models and permafrost data. We evaluate the ability of several climate models to represent permafrost and assess the variability between their results.

    Studying a heterogeneous variable such as permafrost implies conducting analysis at a smaller spatial scale compared with climate models resolution. Our approach consists of applying statistical downscaling methods (SDMs on large- or regional-scale atmospheric variables provided by climate models, leading to local-scale permafrost modelling. Among the SDMs, we first choose a transfer function approach based on Generalized Additive Models (GAMs to produce high-resolution climatology of air temperature at the surface. Then we define permafrost distribution over Eurasia by air temperature conditions. In a first validation step on present climate (CTRL period, this method shows some limitations with non-systematic improvements in comparison with the large-scale fields.

    So, we develop an alternative method of statistical downscaling based on a Multinomial Logistic GAM (ML-GAM, which directly predicts the occurrence probabilities of local-scale permafrost. The obtained permafrost distributions appear in a better agreement with CTRL data. In average for the nine PMIP2 models, we measure a global agreement with CTRL permafrost data that is better when using ML-GAM than when applying the GAM method with air temperature conditions. In both cases, the provided local information reduces the variability between climate models results. This also confirms that a simple relationship between permafrost and the air temperature only is not always sufficient to represent local-scale permafrost.

    Finally, we apply each method on a very different climate, the Last Glacial Maximum (LGM time period, in order to quantify the ability of climate models to represent LGM

  20. Permafrost in Space: first results of experiment "EXOBIOFROST"

    Science.gov (United States)

    Spirina, Elena; Rivkina, Elizaveta; Shmakova, Lubov; Mironov, Vasiliy; Shatilovich, Anastasiya

    Experiment "EXOBIOFROST" was conducted as part of BION-M project of Russian Space Agency. We investigated a response of microbial complexes, including the pure cultures of microorganisms isolated from permafrost and the initial permafrost samples of different origin and age on space conditions. Duration of experiment was 1 month, from April, 19 to May, 19, 2013. All samples were investigated before and after the space flight. For the experiment we selected five samples of permafrost soil from Kolyma-Indigirka Lowland and Antarctica, and also the cultures of microorganisms: Exiguobacterium sibiricum - gram negative bacteria; Colpoda Steinii and Exocolpoda augustini — ciliates, and two strains of Acanthamoeba castelliane. Studies have revealed differences in structure and composition of microbial communities in control and in post-flight samples. All Arctic samples were characterized by a significant, 3-5 orders of magnitude, increase in the number of microorganisms compared to the control samples. However, there is a marked reduction in the amount of extracted DNA in post-flight permafrost samples. Post-flight analysis of ciliates, Colpoda Steinii and Exocolpoda augustini, revealed that 70-97% of cysts are damaged. In general, the primary post-flight analysis and a comparison with the control samples showed that the modern tundra colpoda more resistant to space conditions than they from the ancient permafrost sediments and strain of Colpoda steinii more resistant than the strain Exocolpoda augustini. Post-flight analysis of Acanthamoeba castelliane showed presence of viable cysts capable of excystation. Thus, we can conclude that the experiment "EXOBIOFROST" conducted in open space on the apparatus BION-M No.1 does not prove fatal to permafrost microorganisms.

  1. Comparative Activity and Functional Ecology of Permafrost Soils and Lithic Niches in a Hyper-Arid Polar Desert

    Science.gov (United States)

    Goordial, J.; Davila, A.; Greer, C. W.; Cannam, R.; DiRuggiero, J.; McKay, C. P.; Whyte, L. G.

    2016-01-01

    This study represents the first metagenomic interrogation of Antarctic permafrost and polar cryptoendolithic microbial communities. The results underlie two different habitability conditions in the same location under extreme cold and dryness: the permafrost habitat where viable microbial life and activity is questionable, and the cryptoendolithic habitat which contains organisms capable of growth under the extreme conditions of the Antarctic Dry Valleys.

  2. In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

    Science.gov (United States)

    Kass, Mason A.; Irons, Trevor P; Minsley, Burke J.; Pastick, Neal J.; Brown, Dana R N; Wylie, Bruce K.

    2017-01-01

    Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multi-year investigation into the impacts of wildfires to permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR) response of active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR can image the nucleation of ice within soil pore spaces.

  3. Freeze/Thaw Detection in Permafrost Region with C-Band Scatterometers

    Science.gov (United States)

    Naeimi, Vahid; Paulik, Christoph; Wagner, Wolfgang; Barsch, Annett

    2011-01-01

    Distribution of permafrost is largely controlled by climatic conditions. Current permafrost monitoring methods are based on in-situ measurements and modeling and they are mostly local measurements which offer only limited insight in the impacts of global climate variations on the regional to global scale. Permafrost is a subsurface phenomenon which cannot be directly measured with remotely sensed data. But the spatial distribution, thickness and temperature of permafrost is highly dependent on the condition of the active layer overlaying the permafrost. Satellite data can be utilized for operational monitoring of the permafrost active layer by means of a number of indicators and parameters, which are highly valuable for permafrost modeling and monitoring. In this study we present the usage of backscatter measurements from ASCAT scatterometer onboard Metop for detection of freeze/thaw conditions in high latitudes and validate the results with synoptic meteorological measurements. It is shown that there is a high correlation between frozen/unfrozen flag extracted from ASCAT data and the in-situ air temperature measurements.

  4. Permafrost at Lupin. Interpretation of SAMPO electromagnetic soundings at Lupin

    International Nuclear Information System (INIS)

    Paananen, M.; Ruskeeniemi, T.

    2003-01-01

    The Permafrost Project at the Lupin Mine in northern Canada is an international project, aiming to improve the understanding of behaviour and processes of crystalline bedrock under permafrost conditions. As a part of this project, the Geological Survey of Finland carried out electromagnetic SAMPO soundings in the vicinity of the mine between 11th and 23rd of June 2002 in order to give additional information on the permafrost depth, the location and electrical characteristics of fracture zones and possible talik structures. The total number of sounding points was 214, forming 17 separate survey lines. Used coil separation was 100 - 800 m. According to the temperature data from Lupin Mine, the base of the permafrost is at the depth of 540 m. However, there is no information about the depth distribution outside the mine. The starting point of this survey was the possible existence of a saline water horizon below the permafrost, resulting from repeated segregation and enrichment of salts in front of advancing freezing front. The main result of the survey was a deep conductor, observed at numerous sounding points irrespectively of the measurement configuration. These sounding anomalies form a subhorizontal layer at the depths between 400 and 700 m, in contrast to the vertical orientation of the geological units in the area. According to the results, the conductor gets weaker or deeper close to the Lake Contwoyto and seems to be absent below the lake. There also seems to be a lithological control, since the conducting layer is not observed in granodiorite. It is assumed that the conducting layer represents saline or brackish waters at the base of the permafrost; their calculated TDS-values are in a realistic range for such waters (5000-30 000 mg/l). The subvertical fracture zone VI, previously interpreted from the seismic survey, could be observed as a slight decrease in resistivity in 3 survey profiles using a coil separation of 100 m. (orig.)

  5. Influence of vertical and lateral heat transfer on permafrost thaw, peatland landscape transition, and groundwater flow

    Science.gov (United States)

    Kurylyk, Barret; Masaki, Masaki; Quinton, William L.; McKenzie, Jeffrey M.; Voss, Clifford I.

    2016-01-01

    Recent climate change has reduced the spatial extent and thickness of permafrost in many discontinuous permafrost regions. Rapid permafrost thaw is producing distinct landscape changes in the Taiga Plains of the Northwest Territories, Canada. As permafrost bodies underlying forested peat plateaus shrink, the landscape slowly transitions into unforested wetlands. The expansion of wetlands has enhanced the hydrologic connectivity of many watersheds via new surface and near-surface flow paths, and increased streamflow has been observed. Furthermore, the decrease in forested peat plateaus results in a net loss of boreal forest and associated ecosystems. This study investigates fundamental processes that contribute to permafrost thaw by comparing observed and simulated thaw development and landscape transition of a peat plateau-wetland complex in the Northwest Territories, Canada from 1970 to 2012. Measured climate data are first used to drive surface energy balance simulations for the wetland and peat plateau. Near-surface soil temperatures simulated in the surface energy balance model are then applied as the upper boundary condition to a three-dimensional model of subsurface water flow and coupled energy transport with freeze-thaw. Simulation results demonstrate that lateral heat transfer, which is not considered in many permafrost models, can influence permafrost thaw rates. Furthermore, the simulations indicate that landscape evolution arising from permafrost thaw acts as a positive feedback mechanism that increases the energy absorbed at the land surface and produces additional permafrost thaw. The modeling results also demonstrate that flow rates in local groundwater flow systems may be enhanced by the degradation of isolated permafrost bodies.

  6. Relict Mountain Permafrost Area (Loess Plateau, China) Exhibits High Ecosystem Respiration Rates and Accelerating Rates in Response to Warming

    Science.gov (United States)

    Mu, Cuicui; Wu, Xiaodong; Zhao, Qian; Smoak, Joseph M.; Yang, Yulong; Hu, Lian; Zhong, Wen; Liu, Guimin; Xu, Haiyan; Zhang, Tingjun

    2017-10-01

    Relict permafrost regions are characterized by thin permafrost and relatively high temperatures. Understanding the ecosystem respiration rate (ERR) and its relationship with soil hydrothermal conditions in these areas can provide knowledge regarding the permafrost carbon cycle in a warming world. In this study, we examined a permafrost area, a boundary area, and a seasonally frozen ground area within a relict permafrost region on the east edge of the Qinghai-Tibetan Plateau, China. Measurements from July 2015 to September 2016 showed that the mean annual ecosystem CO2 emissions for the boundary area were greater than the permafrost area. The Q10 value of the ERRs in the seasonally frozen ground area was greater than the permafrost area, indicating that the carbon emissions in the nonpermafrost areas were more sensitive to warming. The 1 year open-top chamber (OTC) warming increased soil temperatures in both the permafrost and seasonally frozen ground areas throughout the year, and the warming increased the ERRs by 1.18 (0.99-1.38, with interquartile range) and 1.13 (0.75-1.54, with interquartile range) μmol CO2 m-2 s-1 in permafrost and seasonally frozen ground areas, respectively. The OTC warming increased annual ERRs by approximately 50% for both permafrost and seasonally frozen ground areas with half the increase occurring during the nongrowing seasons. These results suggest that the ERRs in relict permafrost are high in comparison with arctic regions, and the carbon balance in relict permafrost areas could be greatly changed by climate warming.

  7. Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils

    Science.gov (United States)

    Schädel, Christina; Bader, Martin K.-F.; Schuur, Edward A.G.; Biasi, Christina; Bracho, Rosvel; Čapek, Petr; De Baets, Sarah; Diáková, Kateřina; Ernakovich, Jessica; Estop-Aragones, Cristian; Graham, David E.; Hartley, Iain P.; Iversen, Colleen M.; Kane, Evan S.; Knoblauch, Christian; Lupascu, Massimo; Martikainen, Pertti J.; Natali, Susan M.; Norby, Richard J.; O'Donnell, Jonathan A.; Roy Chowdhury, Taniya; Šantrůčková, Hana; Shaver, Gaius; Sloan, Victoria L.; Treat, Claire C.; Turetsky, Merritt R.; Waldrop, Mark P.; Wickland, Kimberly P.

    2016-01-01

    Increasing temperatures in northern high latitudes are causing permafrost to thaw, making large amounts of previously frozen organic matter vulnerable to microbial decomposition. Permafrost thaw also creates a fragmented landscape of drier and wetter soil conditions that determine the amount and form (carbon dioxide (CO2), or methane (CH4)) of carbon (C) released to the atmosphere. The rate and form of C release control the magnitude of the permafrost C feedback, so their relative contribution with a warming climate remains unclear. We quantified the effect of increasing temperature and changes from aerobic to anaerobic soil conditions using 25 soil incubation studies from the permafrost zone. Here we show, using two separate meta-analyses, that a 10 °C increase in incubation temperature increased C release by a factor of 2.0 (95% confidence interval (CI), 1.8 to 2.2). Under aerobic incubation conditions, soils released 3.4 (95% CI, 2.2 to 5.2) times more C than under anaerobic conditions. Even when accounting for the higher heat trapping capacity of CH4, soils released 2.3 (95% CI, 1.5 to 3.4) times more C under aerobic conditions. These results imply that permafrost ecosystems thawing under aerobic conditions and releasing CO2 will strengthen the permafrost C feedback more than waterlogged systems releasing CO2 and CH4 for a given amount of C.

  8. Microorganisms Trapped Within Permafrost Ice In The Fox Permafrost Tunnel, Alaska

    Science.gov (United States)

    Katayama, T.; Tanaka, M.; Douglas, T. A.; Cai, Y.; Tomita, F.; Asano, K.; Fukuda, M.

    2008-12-01

    Several different types of massive ice are common in permafrost. Ice wedges are easily recognized by their shape and foliated structure. They grow syngenetically or epigenetically as a result of repeated cycles of frost cracking followed by the infiltration of snow, melt water, soil or other material into the open frost cracks. Material incorporated into ice wedges becomes frozen and preserved. Pool ice, another massive ice type, is formed by the freezing of water resting on top of frozen thermokarst sediment or melting wedges and is not foliated. The Fox Permafrost Tunnel in Fairbanks was excavated within the discontinuous permafrost zone of central Alaska and it contains permafrost, ice wedges, and pool ice preserved at roughly -3°C. We collected samples from five ice wedges and three pool ice structures in the Fox Permafrost Tunnel. If the microorganisms were incorporated into the ice during its formation, a community analysis of the microorganisms could elucidate the environment in which the ice was formed. Organic material from sediments in the tunnel was radiocarbon-dated between 14,000 and 30,000 years BP. However, it is still not clear when the ice wedges were formed or subsequently deformed because they are only partially exposed and their upper surfaces are above the tunnel walls. The objectives of our study were to determine the biogeochemical conditions during massive ice formation and to analyze the microbial community within the ices by incubation-based and DNA-based analyses. The geochemical profile and the PCR-DGGE band patterns of bacteria among five ice wedge and 3 portions of pool ice samples were markedly different. The DGGE band patterns of fungi were simple with a few bands of fungi or yeast. The dominant bands of ice wedge and pool ice samples were affiliated with the genus Geomyces and Doratomyces, respectively. Phylogenetic analysis using rRNA gene ITS regions indicated isolates of Geomyces spp. from different ice wedges were affiliated

  9. Map the Permafrost and its Affected Soils and Vegetation on the Tibetan Plateau

    Science.gov (United States)

    Zhao, L.; Sheng, Y.; Pang, Q.; Zou, D.; Wang, Z.; Li, W.; Wu, X.; Yue, G.; Fang, H.; Zhao, Y.

    2015-12-01

    Great amount of literatures had been published to deal with the actual distribution and changes of permafrost on the Tibetan Plateau (TP) on the basis of observed ground temperature dataset along Qinghai-Xizang Highway and/or Railway (QXH/R) during the last several decades. But there is very limited data available in the eastern part of the QXH/R and almost no observation in the western part of QXH/R not only for the observed permafrost data, but also for the dataset on ground surface conditions, such as soil and vegetation, which are used as model parameters, initial variables, or benchmark data sets for calibration, validation, and comparison in various Earth System Models (ESMs). To evaluate the status of permafrost and its environmental conditions, such as the distribution and thermal state of permafrost, soil and vegetation on the TP, detailed investigation on permafrost were conducted in 5 regions with different climatic and geologic conditions over the whole plateau from 2009 to 2013, and more than 100 ground temperatures (GTs) monitoring boreholes were drilled and equipped with thermistors, of which 10 sites were equipped with automatic meteorological stations. Geophysical prospecting methods, such as ground penetrating radar (GPR) and electromagnetic prospecting, were used in the same time to detect the permafrost distribution and thicknesses. The monitoring data revealed that the thermal state of permafrost was well correlated with elevation, and regulated by annual precipitation, local geological, geomorphological and hydrological conditions through heat exchanges between ground and atmosphere. Different models, including GTs statistical model, Common Land Surface Model (CoLM), Noah land surface model and TTOP models, were used to map the permafrost in 5 selected regions and the whole TP, while the investigated and monitored data were used as calibration and validation for all models. Finally, we compiled the permafrost map of the TP, soil and vegetation

  10. Geophysical mapping of palsa peatland permafrost

    Science.gov (United States)

    Sjöberg, Y.; Marklund, P.; Pettersson, R.; Lyon, S. W.

    2015-03-01

    Permafrost peatlands are hydrological and biogeochemical hotspots in the discontinuous permafrost zone. Non-intrusive geophysical methods offer a possibility to map current permafrost spatial distributions in these environments. In this study, we estimate the depths to the permafrost table and base across a peatland in northern Sweden, using ground penetrating radar and electrical resistivity tomography. Seasonal thaw frost tables (at ~0.5 m depth), taliks (2.1-6.7 m deep), and the permafrost base (at ~16 m depth) could be detected. Higher occurrences of taliks were discovered at locations with a lower relative height of permafrost landforms, which is indicative of lower ground ice content at these locations. These results highlight the added value of combining geophysical techniques for assessing spatial distributions of permafrost within the rapidly changing sporadic permafrost zone. For example, based on a back-of-the-envelope calculation for the site considered here, we estimated that the permafrost could thaw completely within the next 3 centuries. Thus there is a clear need to benchmark current permafrost distributions and characteristics, particularly in under studied regions of the pan-Arctic.

  11. Moving toward implementation : an examination of the organizational and political structures of transit-oriented development.

    Science.gov (United States)

    2009-06-01

    The research explores the costs and impacts of Transit Oriented Development (TOD) and : addresses the rationale for designing transit-oriented neighborhoods. It also documents the : outcomes and the impacts of implementing such projects and examines ...

  12. Affordable Housing in transit-oriented developments : impacts on driving and policy approaches.

    Science.gov (United States)

    2017-04-01

    This paper studies the intersection of policies promoting affordable housing, transit-oriented developments (TODs), and the reduction of vehicle miles traveled (VMT) in metropolitan areas. In particular, this paper focuses on the following questions:...

  13. Effects of permafrost thaw on carbon emissions under aerobic and anaerobic environments in the Great Hing'an Mountains, China.

    Science.gov (United States)

    Song, Changchun; Wang, Xianwei; Miao, Yuqing; Wang, Jiaoyue; Mao, Rong; Song, Yanyu

    2014-07-15

    The carbon (C) pool of permafrost peatland is very important for the global C cycle. Little is known about how permafrost thaw could influence C emissions in the Great Hing'an Mountains of China. Through aerobic and anaerobic incubation experiments, we studied the effects of permafrost thaw on CH4 and CO2 emissions. The rates of CH4 and CO2 emissions were measured at -10, 0 and 10°C. Although there were still C emissions below 0°C, rates of CH4 and CO2 emissions significantly increased with permafrost thaw under aerobic and anaerobic conditions. The C release under aerobic conditions was greater than under anaerobic conditions, suggesting that permafrost thaw and resulting soil environment change should be important influences on C emissions. However, CH4 stored in permafrost soils could affect accurate estimation of CH4 emissions from microbial degradation. Calculated Q10 values in the permafrost soils were significantly higher than values in active-layer soils under aerobic conditions. Our results highlight that permafrost soils have greater potential decomposability than soils of the active layer, and such carbon decomposition would be more responsive to the aerobic environment. © 2013 Elsevier B.V. All rights reserved.

  14. Review: Impacts of permafrost degradation on inorganic chemistry of surface fresh water

    Science.gov (United States)

    Colombo, Nicola; Salerno, Franco; Gruber, Stephan; Freppaz, Michele; Williams, Mark; Fratianni, Simona; Giardino, Marco

    2018-03-01

    Recent studies have shown that climate change is impacting the inorganic chemical characteristics of surface fresh water in permafrost areas and affecting aquatic ecosystems. Concentrations of major ions (e.g., Ca2 +, Mg2 +, SO42 -, NO3-) can increase following permafrost degradation with associated deepening of flow pathways and increased contributions of deep groundwater. In addition, thickening of the active layer and melting of near-surface ground ice can influence inorganic chemical fluxes from permafrost into surface water. Permafrost degradation has also the capability to modify trace element (e.g., Ni, Mn, Al, Hg, Pb) contents in surface water. Although several local and regional modifications of inorganic chemistry of surface fresh water have been attributed to permafrost degradation, a comprehensive review of the observed changes is lacking. The goal of this paper is to distil insight gained across differing permafrost settings through the identification of common patterns in previous studies, at global scale. In this review we focus on three typical permafrost configurations (pervasive permafrost degradation, thermokarst, and thawing rock glaciers) as examples and distinguish impacts on (i) major ions and (ii) trace elements. Consequences of warming climate have caused spatially-distributed progressive increases of major ion and trace element delivery to surface fresh water in both polar and mountain areas following pervasive permafrost degradation. Moreover, localised releases of major ions and trace elements to surface water due to the liberation of soluble materials sequestered in permafrost and ground ice have been found in ice-rich terrains both at high latitude (thermokarst features) and high elevation (rock glaciers). Further release of solutes and related transport to surface fresh water can be expected under warming climatic conditions. However, complex interactions among several factors able to influence the timing and magnitude of the impacts

  15. Model for the analysis of transitories and stability of a BWR reactor with fuel of thorium

    International Nuclear Information System (INIS)

    Nunez C, A.; Espinosa P, G.; Francois L, J.L.

    2004-01-01

    In this work it is described the thermo hydraulic and neutronic pattern used to simulate the behavior of a nucleus of thorium-uranium under different conditions of operation. The analysed nucleus was designed with base to assemblies that operate under the cover-seed concept. The pattern was proven to conditions of stationary state and transitory state. Here it is only presented the simulation of the one SCRAM manual and it is compared in the behavior of a nucleus with UO 2 . Additionally one carries out an analysis of stability taking into account the four corners that define the area of stability of the map flow-power and to conditions of 100% of flow and 100% of power. The module of stability is based on the pattern of Lahey and Podowsky to estimate the drops of pressure during a perturbation. It is concludes that the behavior of this nucleus is not very different to the one shown by the nuclei loaded with the fuel of UO 2 . (Author)

  16. Hydrogeology, Chemical and Microbial Activity Measurement Through Deep Permafrost

    Science.gov (United States)

    Stotler, R.L.; Frape, S.K.; Freifeld, B.M.; Holden, B.; Onstott, T.C.; Ruskeeniemi, T.; Chan, E.

    2011-01-01

    Little is known about hydrogeochemical conditions beneath thick permafrost, particularly in fractured crystalline rock, due to difficulty in accessing this environment. The purpose of this investigation was to develop methods to obtain physical, chemical, and microbial information about the subpermafrost environment from a surface-drilled borehole. Using a U-tube, gas and water samples were collected, along with temperature, pressure, and hydraulic conductivity measurements, 420 m below ground surface, within a 535 m long, angled borehole at High Lake, Nunavut, Canada, in an area with 460-m-thick permafrost. Piezometric head was well above the base of the permafrost, near land surface. Initial water samples were contaminated with drill fluid, with later samples values ???5??? lower than the local surface water. The fluid isotopic composition was affected by the permafrost-formation process. Nonbacteriogenic CH4 was present and the sample location was within methane hydrate stability field. Sampling lines froze before uncontaminated samples from the subpermafrost environment could be obtained, yet the available time to obtain water samples was extended compared to previous studies. Temperature measurements collected from a distributed temperature sensor indicated that this issue can be overcome easily in the future. The lack of methanogenic CH4 is consistent with the high sulfate concentrations observed in cores. The combined surface-drilled borehole/U-tube approach can provide a large amount of physical, chemical, and microbial data from the subpermafrost environment with few, controllable, sources of contamination. ?? 2010 The Author(s). Journal compilation ?? 2010 National Ground Water Association.

  17. Permafrost Meta-Omics and Climate Change

    Science.gov (United States)

    Mackelprang, Rachel; Saleska, Scott R.; Jacobsen, Carsten Suhr; Jansson, Janet K.; Taş, Neslihan

    2016-06-01

    Permanently frozen soil, or permafrost, covers a large portion of the Earth's terrestrial surface and represents a unique environment for cold-adapted microorganisms. As permafrost thaws, previously protected organic matter becomes available for microbial degradation. Microbes that decompose soil carbon produce carbon dioxide and other greenhouse gases, contributing substantially to climate change. Next-generation sequencing and other -omics technologies offer opportunities to discover the mechanisms by which microbial communities regulate the loss of carbon and the emission of greenhouse gases from thawing permafrost regions. Analysis of nucleic acids and proteins taken directly from permafrost-associated soils has provided new insights into microbial communities and their functions in Arctic environments that are increasingly impacted by climate change. In this article we review current information from various molecular -omics studies on permafrost microbial ecology and explore the relevance of these insights to our current understanding of the dynamics of permafrost loss due to climate change.

  18. PYRN-Bib: The Permafrost Young Researchers Network Bibliography of Permafrost-Related Degree-Earning Theses

    Science.gov (United States)

    Grosse, Guido; Lantuit, Hugues; Gärtner-Roer, Isabelle

    2010-05-01

    PYRN-Bib is an international bibliographical database aiming at collecting and distributing information on all theses submitted for earning a scientific degree in permafrost-related research. PYRN-Bib is hosted by the Permafrost Young Researchers Network (PYRN, http://pyrn.ways.org), an international network of early career students and young scientists in permafrost related research with currently more than 750 members. The fully educational, non-profit project PYRN-Bib is published under the patronage of the International Permafrost Association (IPA). The bibliography covers all theses as long as they clearly treat aspects of permafrost research from such diverse fields as: Geophysics, Geology, Cryolithology, Biology, Biogeochemistry, Microbiology, Astrobiology, Chemistry, Engineering, Geomorphology, Remote Sensing, Modeling, Mineral and Hydrocarbon Exploration, and Science History and Education. The specific goals of PYRN-Bib are (1) to generate a comprehensive database that includes all degree-earning theses (e.g. Diploma, Ph.D., Master, etc.), coming from any country and any scientific field, under the single condition that the thesis is strongly related to research on permafrost and/or periglacial processes; (2) to reference unique but buried sources of information including theses published in languages other than English; (3) to make the database widely available to the scientific community and the general public; (4) to solicit PYRN membership; and (5) to provide a mean to map the evolution of permafrost research over the last decades, including regional trends, shifts in research direction, and/or the place of permafrost research in society. PYRN-Bib is available online and maintained by PYRN. The complete bibliography can be downloaded at no cost and is offered in different file formats: tagged Endnote library, XML, BibTex, and PDF. New entries are continuously provided by PYRN members and the scientific community. PYRN-Bib currently contains more than

  19. The transcriptional response of microbial communities in thawing Alaskan permafrost soils.

    Science.gov (United States)

    Coolen, Marco J L; Orsi, William D

    2015-01-01

    Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gasses, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. Here, we performed a pilot study using ultrahigh throughput Illumina HiSeq sequencing of reverse transcribed messenger RNA to obtain a detailed overview of active metabolic pathways and responsible organisms in up to 70 cm deep permafrost soils at a moist acidic tundra location in Arctic Alaska. The transcriptional response of the permafrost microbial community was compared before and after 11 days of thaw. In general, the transcriptional profile under frozen conditions suggests a dominance of stress responses, survival strategies, and maintenance processes, whereas upon thaw a rapid enzymatic response to decomposing soil organic matter (SOM) was observed. Bacteroidetes, Firmicutes, ascomycete fungi, and methanogens were responsible for largest transcriptional response upon thaw. Transcripts indicative of heterotrophic methanogenic pathways utilizing acetate, methanol, and methylamine were found predominantly in the permafrost table after thaw. Furthermore, transcripts involved in acetogenesis were expressed exclusively after thaw suggesting that acetogenic bacteria are a potential source of acetate for acetoclastic methanogenesis in freshly thawed permafrost. Metatranscriptomics is shown here to be a useful approach for inferring the activity of permafrost microbes that has potential to improve our understanding of permafrost SOM bioavailability and biogeochemical mechanisms contributing to greenhouse gas emissions as a result of permafrost thaw.

  20. Impact of Black Dust Pollution on Permafrost Temperature Regime in Pechora Basin

    Science.gov (United States)

    Khilimonyuk, V.; Pustovoit, G.; Filatova, M.

    2011-12-01

    Pechora Coal basin locates in North- Easter part of Europe within permafrost zone. The coal mining and post processing lead to emission of black dust (BD) and pollution of Earth surface. The scale of snow pollution surrounding Vorkuta city reaches to 260 g/sq.m of dust that is about 1000 ppmm BD concentration in snow before melting period. Such a large concentration of dust reduces snow reflectivity (Warren and Wiscombe, 1980; Chýlek et al., 1983,Gorbacheva, 1984, Zender et al, 2010) and can thereby trigger albedo feedbacks. The goal of this study is to evaluate the role of dirty surface albedo in the observed changing of permafrost regime in this basin. Two key sites: Workuta (North permafrost zone) and Inta (South permafrost zone) areas were selected for this study. For each site the zoning of territory by typical conditions of permafrost formation was performed. For the selected typical landscapes 1-D vertical heat transfer model coupled with the surface radiation-thermal balance equation at topsoil was simulated. The simulation was performed for the soil profile of 20 m depth during 20 years period with periodical input data at dirty surface averaged on monthly base. The initial measured not disturbed soil temperature profile was used for assessment the soil thermal property for the given landscape and natural surface radiation-thermal balance. The annual cycle of albedo change for dirty surface was taken from experimental measurement (Gorbacheva, 1984) for both sites as the function of the distance from the dust source. The simulation results next were used for mapping the vulnerability of permafrost thermal regime due to black dust pollution. Generally the simulation results show that South permafrost zone with mean temperature of permafrost (-0.5 -0.1C) is more vulnerable to albedo change than North permafrost zone with mean temperature (-2.5 -2C) for the same order of dust impact on albedo.

  1. The transcriptional response of microbial communities in thawing Alaskan permafrost soils

    Directory of Open Access Journals (Sweden)

    M J L Coolen

    2015-03-01

    Full Text Available Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gases, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. Here, we performed a pilot study using ultrahigh throughput Illumina HiSeq sequencing of reverse transcribed messenger RNA to obtain a detailed overview of active metabolic pathways and responsible organisms in up to 70 cm deep permafrost soils at a moist acidic tundra location in Arctic Alaska. The transcriptional response of the permafrost microbial community was compared before and after eleven days of thaw. In general, the transcriptional profile under frozen conditions suggests a dominance of stress responses, survival strategies, and maintenance processes, whereas upon thaw a rapid enzymatic response to decomposing soil organic matter (SOM was observed. Bacteroidetes, Firmicutes, ascomycete fungi, and methanogens were responsible for largest transcriptional response upon thaw. Transcripts indicative of heterotrophic methanogenic pathways utilizing acetate, methanol, and methylamine were found predominantly in the permafrost table after thaw. Furthermore, transcripts involved in acetogenesis were expressed exclusively after thaw suggesting that acetogenic bacteria are a potential source of acetate for acetoclastic methanogenesis in freshly thawed permafrost. Metatranscriptomics is shown here to be a useful approach for inferring the activity of permafrost microbes that has potential to improve our understanding of permafrost SOM bioavailability and biogeochemical mechanisms contributing to greenhouse gas emissions as a result of permafrost thaw.

  2. Molecular investigations into a globally important carbon pool: Permafrost-protected carbon in Alaskan soils

    Science.gov (United States)

    Waldrop, M.P.; Wickland, K.P.; White, Rickie; Berhe, A.A.; Harden, J.W.; Romanovsky, V.E.

    2010-01-01

    The fate of carbon (C) contained within permafrost in boreal forest environments is an important consideration for the current and future carbon cycle as soils warm in northern latitudes. Currently, little is known about the microbiology or chemistry of permafrost soils that may affect its decomposition once soils thaw. We tested the hypothesis that low microbial abundances and activities in permafrost soils limit decomposition rates compared with active layer soils. We examined active layer and permafrost soils near Fairbanks, AK, the Yukon River, and the Arctic Circle. Soils were incubated in the lab under aerobic and anaerobic conditions. Gas fluxes at -5 and 5 ??C were measured to calculate temperature response quotients (Q10). The Q10 was lower in permafrost soils (average 2.7) compared with active layer soils (average 7.5). Soil nutrients, leachable dissolved organic C (DOC) quality and quantity, and nuclear magnetic resonance spectroscopy of the soils revealed that the organic matter within permafrost soils is as labile, or even more so, than surface soils. Microbial abundances (fungi, bacteria, and subgroups: methanogens and Basidiomycetes) and exoenzyme activities involved in decomposition were lower in permafrost soils compared with active layer soils, which, together with the chemical data, supports the reduced Q10 values. CH4 fluxes were correlated with methanogen abundance and the highest CH4 production came from active layer soils. These results suggest that permafrost soils have high inherent decomposability, but low microbial abundances and activities reduce the temperature sensitivity of C fluxes. Despite these inherent limitations, however, respiration per unit soil C was higher in permafrost soils compared with active layer soils, suggesting that decomposition and heterotrophic respiration may contribute to a positive feedback to warming of this eco region. Published 2010. This article is a US Government work and is in the public domain in the

  3. Human-Modified Permafrost Complexes in Urbanized Areas of the Russian North

    Science.gov (United States)

    Grebenets, V. I.; Streletskiy, D. A.

    2013-12-01

    Economic development in permafrost regions is accompanied by modification of natural geocryological conditions. Drastic landscape transformations in urbanized areas on permafrost are characterized by changes of heat and moisture exchange in permafrost - atmosphere system, and by engineering and technogenic influence upon the frozen ground, leading to alteration of its physical, thermal and mechanical properties. In northern cities this leads to overall increase of ground temperature relative to undisturbed areas and intensification of hazardous cryogenic processes in areas under engineering development, which together leads to reduction in stability of geotechnical environment. For example, deformations of structures in Norilsk district, Northern Siberia, in the last 15 years, became much more abundant than those revealed throughout the previous 50 years. About 250 large buildings in the local towns were deformed considerably due to deterioration of geocryological conditions, about 100 structures were functioning in emergency state, and almost 50 nine- and five-storey houses, built in the 1960-80s, have been recently disassembled. Increase in accident risk for various facilities (water and oil pipelines, industrial enterprises, etc.) enhances the technogenic pressure on permafrost, leading to the new milestone of changes in permafrost characteristics, i.e. to creation of 'another reality' of geocryological conditions. Social and natural factors dictate clustered spatial pattern of industrial development in permafrost regions. Cryogenic processes within the urban areas on permafrost are seldom similar with those under the natural conditions as intensity, duration and extent of the processes changes under technogenic impacts. Moreover, new cryogenic processes and phenomena may occur, which have not been typical for a given region. This makes mapping and characterization of these processes difficult task. Peculiar natural-technogenic geocryological complexes (NTGC

  4. Rapid disturbances in Arctic permafrost regions (Invited)

    Science.gov (United States)

    Grosse, G.; Romanovsky, V. E.; Arp, C. D.; Jones, B. M.

    2013-12-01

    Permafrost thaw is often perceived as a slow process dominated by press disturbances such as gradual active layer thickening. However, various pulse disturbances such as thermokarst formation can substantially increase the rate of permafrost thaw and result in rapid landscape change on sub-decadal to decadal time scales. Other disturbances associated with permafrost thaw are even more dynamic and unfold on sub-annual timescales, such as catastrophic thermokarst lake drainage. The diversity of processes results in complex feedbacks with soil carbon pools, biogeochemical cycles, hydrology, and flora and fauna, and requires a differentiated approach when quantifying how these ecosystem componentsare affected,how vulnerablethey are to rapid change, and what regional to global scale impacts result. Here we show quantitative measurements for three examples of rapid pulse disturbances in permafrost regions as observed with remote sensing data time series: The formation of a mega thaw slump (>50 ha) in syngenetic permafrost in Siberia, the formation of new thermokarst ponds in ice-rich permafrost regions in Alaska and Siberia, and the drainage of thermokarst lakes along a gradient of permafrost extent in Western Alaska. The surprising setting and unabated growth of the mega thaw slump during the last 40 years indicates that limited information on panarctic ground ice distribution, abundance, and vulnerability remains a key gap for reliable projections of thermokarst and thermo-erosion impacts, and that the natural limits on the growth and size of thaw slumps are still poorly understood. Observed thermokarst pond formation and expansion in our study regions was closely tied to ice-rich permafrost terrain, such as syngenetic Yedoma uplands, but was also found in old drained thermokarst lake basins with epigenetic permafrost and shallow drained thermokarst lake basins whose ground ice had not been depleted by the prior lake phase. The very different substrates in which new

  5. Climate warming over the past half century has led to thermal degradation of permafrost on the Qinghai-Tibet Plateau

    Science.gov (United States)

    Ran, Youhua; Li, Xin; Cheng, Guodong

    2018-02-01

    Air temperature increases thermally degrade permafrost, which has widespread impacts on engineering design, resource development, and environmental protection in cold regions. This study evaluates the potential thermal degradation of permafrost over the Qinghai-Tibet Plateau (QTP) from the 1960s to the 2000s using estimated decadal mean annual air temperatures (MAATs) by integrating remote-sensing-based estimates of mean annual land surface temperatures (MASTs), leaf area index (LAI) and fractional snow cover values, and decadal mean MAAT date from 152 weather stations with a geographically weighted regression (GWR). The results reflect a continuous rise of approximately 0.04 °C a-1 in the decadal mean MAAT values over the past half century. A thermal-condition classification matrix is used to convert modelled MAATs to permafrost thermal type. Results show that the climate warming has led to a thermal degradation of permafrost in the past half century. The total area of thermally degraded permafrost is approximately 153.76 × 104 km2, which corresponds to 88 % of the permafrost area in the 1960s. The thermal condition of 75.2 % of the very cold permafrost, 89.6 % of the cold permafrost, 90.3 % of the cool permafrost, 92.3 % of the warm permafrost, and 32.8 % of the very warm permafrost has been degraded to lower levels of thermal condition. Approximately 49.4 % of the very warm permafrost and 96 % of the likely thawing permafrost has degraded to seasonally frozen ground. The mean elevations of the very cold, cold, cool, warm, very warm, and likely thawing permafrost areas increased by 88, 97, 155, 185, 161, and 250 m, respectively. The degradation mainly occurred from the 1960s to the 1970s and from the 1990s to the 2000s. This degradation may lead to increased risks to infrastructure, reductions in ecosystem resilience, increased flood risks, and positive climate feedback effects. It therefore affects the well-being of millions of people

  6. Analogical reasoning and the differential outcome effect: transitory bridging of the conceptual gap for rhesus monkeys (Macaca mulatta).

    Science.gov (United States)

    Flemming, Timothy M; Thompson, Roger K R; Beran, Michael J; Washburn, David A

    2011-07-01

    Monkeys, unlike chimpanzees and humans, have a marked difficulty acquiring relational matching-to-sample (RMTS) tasks that likely reflect the cognitive foundation upon which analogical reasoning rests. In the present study, rhesus monkeys (Macaca mulatta) completed a categorical (identity and nonidentity) RMTS task with differential reward (pellet ratio) and/or punishment (timeout ratio) outcomes for correct and incorrect choices. Monkeys in either differential reward-only or punishment-only conditions performed at chance levels. However, the RMTS performance of monkeys experiencing both differential reward and punishment conditions was significantly better than chance. Subsequently when all animals experienced nondifferential outcomes tests, their RMTS performance levels were at chance. These results indicate that combining differential reward and punishment contingencies provide an effective, albeit transitory, scaffolding for monkeys to judge analogical relations-between-relations. PsycINFO Database Record (c) 2011 APA, all rights reserved

  7. Permafrost degradation in West Greenland

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Ingeman-Nielsen, Thomas

    2012-01-01

    Important aspects of civil engineering in West Greenland relate to the presence of permafrost and mapping of the annual and future changes in the active layer due to the ongoing climatically changes in the Arctic. The Arctic Technology Centre (ARTEK) has worked more than 10 years on this topic...... parameters. It is planned as decision and planning tool for town planners and engineers in local municipality governments and to consulting engineers and contractors in Greenland, which also may be used in other arctic regions. Risk is classified in four categories: Low, Limited, Medium and High based...

  8. Modeling near-shore subsea permafrost degradation in the Laptev Sea

    Science.gov (United States)

    Kneier, F.; Langer, M.; Overduin, P. P.

    2012-12-01

    Most subsea permafrost in the Arctic Ocean shelf regions is relict terrestrial permafrost that was inundated by sea water by rising sea levels after the last glacial period. Permafrost usually degrades offshore under the influence of sea-bottom temperatures, salt infiltration and a wide range of near-shore coastal processes. Subsea permafrost instability has important potential implications due to the release of methane to the atmosphere and by increasing coastal erosion rates. Our objectives are to employ meso-scale numerical calculations (from meter to kilometer, 1000s of years) in connection with borehole data from the Laptev Sea to model the transition of permafrost from onshore to offshore conditions. The goal is to identify key processes driving permafrost degradation in the near-shore zone of the shelf. The heat transfer equation is solved numerically taking into account freeze-thaw processes in a three-phase heat capacity / conductivity model. Sediment composition and initial temperature profiles are derived from field and laboratory analysis of the borehole data. Our approach neglects some processes such as solute diffusion, but includes the effect of pore water salinity on phase state and thermal properties. Measured temperature profiles are compared to the modeled subsea soil temperature evolution over the course of the 2500 year transgression of the farthest offshore borehole in the transect. The degradation of the ice-bearing permafrost table or thaw depth is of special interest due to its direct relation to sediment stability and as the most readily discernible feature in the field observations. Temperature profiles generally agree well with model calculations reproducing the almost isothermal permafrost profiles currently observed, but show more variation potentially partially caused by drilling disturbances. The thaw depth is mainly driven by salt contamination and infiltration into deeper pore water with time. Complicating near-shore processes

  9. The potential significance of permafrost to the behaviour of a deep radioactive waste repository

    International Nuclear Information System (INIS)

    McEwen, T.; Marsily, G.de

    1991-02-01

    Permafrost is one of the scenarios that is being considered as part of the groundwater flow and transport modelling for the Project-90 assessment. It is included as one of the primary Features, Events and Processes (FEPs) which are being kept outside the Process System in the SKB/SKI scenario development project. There is a large amount of evidence that Sweden has suffered several cycles of permafrost development over the Quaternary, approximately the last 2My, and climatic predictions for the next hundred thousand years suggest that similar climatic cycling is likely to occur. The presence of permafrost could have important effects on the hydrogeological regime and could therefore be important in modifying the release and dispersion of radionuclides from a repository. The climatic conditions of permafrost would also influence radionuclide migration and accumulation in the biosphere and the associated radiation exposure of man. These biosphere aspects are not considered here but the implications for discharge into the biosphere are examined, including the abstraction of groundwater by man in permafrost regions. This report reviews the evidence relating to permafrost development and discusses the possible implications for the long-term safety of a deep repository. (78 refs.) (au)

  10. International Permafrost Field Courses in Siberia: the Synthesis of Research and Education

    Science.gov (United States)

    Ablyazina, D.; Boitsov, A.; Grebenets, V.; Kaverin, D.; Klene, A.; Kurchatova, A.; Pfeiffer, E. M.; Zschocke, A.; Shiklomanov, N.; Streletskiy, D.

    2009-04-01

    During summers of 2007 and 2008 a series of International University Courses on Permafrost (IUCP) were conducted in West Siberia, Russia. Courses were organized as part of the International Permafrost Association (IPA) International Polar Year activities. The North of West Siberia region was selected to represent diverse permafrost, climatic and landscape conditions. The courses were jointly organized by the Moscow State University (MSU) and the Tumen' Oil and Gas University (TOGU) with the help from German and U.S. institutions. The program attracted undergraduate and graduate students with diverse interests and backgrounds from Germany, Russia and the U.S. and involved instructors specializing in different aspects of permafrost research. Courses were designed to address three major topics of permafrost-related research: a) permafrost environments characteristic of the discontinuous and continuous zones; b) field instrumentation and techniques; c) permafrost engineering and problems of development in permafrost regions. Methodologically, courses consisted of systematic permafrost investigations at long-term monitoring sites and survey-type expeditions. Systematic, process-based investigations were conducted at a network of sites which constitute the TEPO established by TOGU in collaboration with the gas company NadymGasProm. The observation complex includes an array of 30-m deep boreholes equipped with automatic data collection systems and representing characteristic permafrost landscapes of West Siberia. Boreholes are complemented by sites for snow cover, vegetation, soil, ground ice, and geomorphologic investigations. As part of student research activities, four new Circumpolar Active Layer Monitoring (CALM) sites were established in proximity to boreholes for monitoring spatial distribution and long-term dynamic of the active layer. New sites represent diverse landscapes characteristic of the West Siberian previously underrepresented in the CALM network

  11. Does mountain permafrost in Mongolia control water availability?

    Science.gov (United States)

    Menzel, Lucas; Kopp, Benjamin; Munkhjargal, Munkhdavaa

    2016-04-01

    In semi-arid Mongolia, continuous and discontinuous permafrost covers wide parts of the mountains, especially in the northwest of the country. Long-term analysis of annual discharge from rivers draining the mountainous parts shows high temporal variability, with some evidence of decreasing trends, accompanied by decreased intra-annual variability. Investigations show that annual precipitation features small changes while annual air temperature significantly increased over the last decades, with warming rates clearly outranging the global average. Widespread and drastic changes in land cover through forest fires in northern Mongolia might have an additional impact on water retention and the stability of permafrost. Hence, there is concern about an increased degradation of mountain permafrost and a possible impact on river discharge and water availability. Decreased water availability from the mountains would have strong socio-economic implications for the population living in the steppe belt downstream the mountains. Therefore, a monitoring program has been conducted in northern Mongolia that aims to improve the understanding of how climate change and forest fires are influencing mountain permafrost and water resources. The study region, Sugnugur valley, is located about 100 km north of Ulaanbaatar and includes the transition belt between the steppe, the boreal zone and the alpine tundra of the Khentii Mountains. Extensive measurements of soil temperatures, soil moisture, discharge and climatic parameters have been carried out along transects which stretch across the Sugnugur river valley and include steppe, boreal forest as well as burnt forest. First results indicate that the environmental conditions show drastic changes after forest fire, with reduced water retention in the headwaters. After forest fires, changing runoff processes above the permafrost table have been observed, where water drains rapidly along preferential flow paths. This eventually leads to

  12. 77 FR 21098 - Notice of Meeting of the Environmental Financial Advisory Board (EFAB), and Transit-Oriented...

    Science.gov (United States)

    2012-04-09

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9656-6] Notice of Meeting of the Environmental Financial... Financial Advisory Board (EFAB) will hold a meeting on May 22-23, 2012 and a Transit-Oriented Development... discussed include: clean air technology; tribal environmental programs; transit-oriented development; energy...

  13. Analysing the environmental harms caused by coal mining and its protection measures in permafrost regions of Qinghai–Tibet Plateau

    Directory of Open Access Journals (Sweden)

    Wei Cao

    2017-09-01

    Full Text Available The coal mining has brought a series of ecological problems and environmental problems in permafrost regions. Taking Muli coal-mining area as an example, this article attempts to analyse the environmental harms caused by coal mining and its protection measures in permafrost regions of Qinghai–Tibet Plateau. This article analyses the influence of open mining on the surrounding permafrost around the open pit by using the numerical simulation. The results show that (1 based on the interrelation between coal mining and permafrost environment, these main environmental harm include the permafrost change and the natural environment change in cold regions; (2 once the surface temperature rises due to open mining, the permafrost will disappear with the increase of exploitation life. If considering the solar radiation, the climate conditions and the geological condition around the pit edge, the maximum thaw depth will be more than 2 m; (3 the protection measures are proposed to avoid the disadvantage impact on the permafrost environment caused by coal mining. It will provide a scientific basis for the resource development and environment protection in cold regions.

  14. The role of climate change in regulating Arctic permafrost peatland hydrological and vegetation change over the last millennium

    Science.gov (United States)

    Zhang, Hui; Piilo, Sanna R.; Amesbury, Matthew J.; Charman, Dan J.; Gallego-Sala, Angela V.; Väliranta, Minna M.

    2018-02-01

    Climate warming has inevitable impacts on the vegetation and hydrological dynamics of high-latitude permafrost peatlands. These impacts in turn determine the role of these peatlands in the global biogeochemical cycle. Here, we used six active layer peat cores from four permafrost peatlands in Northeast European Russia and Finnish Lapland to investigate permafrost peatland dynamics over the last millennium. Testate amoeba and plant macrofossils were used as proxies for hydrological and vegetation changes. Our results show that during the Medieval Climate Anomaly (MCA), Russian sites experienced short-term permafrost thawing and this induced alternating dry-wet habitat changes eventually followed by desiccation. During the Little Ice Age (LIA) both sites generally supported dry-hummock habitats, at least partly driven by permafrost aggradation. However, proxy data suggest that occasionally, MCA habitat conditions were drier than during the LIA, implying that evapotranspiration may create important additional eco-hydrological feedback mechanisms under warm conditions. All sites showed a tendency towards dry conditions as inferred from both proxies starting either from ca. 100 years ago or in the past few decades after slight permafrost thawing, suggesting that recent warming has stimulated surface desiccation rather than deeper permafrost thawing. This study shows links between two important controls over hydrology and vegetation changes in high-latitude peatlands: direct temperature-induced surface layer response and deeper permafrost layer-related dynamics. These data provide important backgrounds for predictions of Arctic permafrost peatlands and related feedback mechanisms. Our results highlight the importance of increased evapotranspiration and thus provide an additional perspective to understanding of peatland-climate feedback mechanisms.

  15. The common-trend and transitory dynamics in real exchange rate fluctuations

    DEFF Research Database (Denmark)

    Bergman, Ulf Michael; Cheung, Yin-Wong; Lai, Kon S.

    2011-01-01

    This study examines the behaviour of both Common Trend (CT) and transitory components of Real Exchange Rate (RER) fluctuations under the current float. The CT component is in most cases found to be sizeable, albeit its relative importance can vary considerably across major currencies and its...

  16. The role of institutional innovation and learning when pursuing transit-oriented development strategies : EURA 2013

    NARCIS (Netherlands)

    Tan, Wendy

    2013-01-01

    Transit-oriented development strategies (TODS) are widely pursued by planners and policy makers. However, there is a lack of0clarity on how institutional innovation and learning accompanying0institutional change0facilitates an explicit shift towards a conducive context for TODS. This is evident in

  17. Experimental warming increased soil nitrogen sink in the Tibetan permafrost

    Science.gov (United States)

    Chang, Ruiying; Wang, Genxu; Yang, Yuanhe; Chen, Xiaopeng

    2017-07-01

    In permafrost soil, warming regulates the nitrogen (N) cycle either by stimulating N transformation or by enhancing cryoturbation, the mixture of soil layers due to repeated freeze thaw. Here N isotopic values (δ15N) of plants and the soil were investigated in a 7 year warming experiment in a permafrost-affected alpine meadow on the Qinghai-Tibetan Plateau. The results revealed that warming significantly decreased the δ15N in the plant (aboveground and belowground parts) and different soil fractions (clay and silt fraction, aggregate, and bulk soil). The decreased soil δ15N was associated with an increase in soil N stock due to greater N fixation. The incremental N retention in plants and soil mineral-associated fractions from warming resulted in a decrease in soil inorganic N, which constrains the role of nitrification/denitrification in soil δ15N, suggesting a restrained rather than an open N cycle. Furthermore, enhanced cryoturbation under warming, identified by a downward redistribution of 137Cs into deeper layers, promoted N protection from transformation. Overall, the decrease in soil δ15N indicated higher rates of N input through fixation relative to N loss through nitrification and denitrification in permafrost-affected ecosystems under warming conditions.

  18. Hydrogeology, chemical and microbial activity measurement through deep permafrost.

    Science.gov (United States)

    Stotler, Randy L; Frape, Shaun K; Freifeld, Barry M; Holden, Brian; Onstott, Tullis C; Ruskeeniemi, Timo; Chan, Eric

    2011-01-01

    Little is known about hydrogeochemical conditions beneath thick permafrost, particularly in fractured crystalline rock, due to difficulty in accessing this environment. The purpose of this investigation was to develop methods to obtain physical, chemical, and microbial information about the subpermafrost environment from a surface-drilled borehole. Using a U-tube, gas and water samples were collected, along with temperature, pressure, and hydraulic conductivity measurements, 420 m below ground surface, within a 535 m long, angled borehole at High Lake, Nunavut, Canada, in an area with 460-m-thick permafrost. Piezometric head was well above the base of the permafrost, near land surface. Initial water samples were contaminated with drill fluid, with later samples <40% drill fluid. The salinity of the non-drill fluid component was <20,000 mg/L, had a Ca/Na ratio above 1, with δ(18) O values ∼5‰ lower than the local surface water. The fluid isotopic composition was affected by the permafrost-formation process. Nonbacteriogenic CH(4) was present and the sample location was within methane hydrate stability field. Sampling lines froze before uncontaminated samples from the subpermafrost environment could be obtained, yet the available time to obtain water samples was extended compared to previous studies. Temperature measurements collected from a distributed temperature sensor indicated that this issue can be overcome easily in the future. The lack of methanogenic CH(4) is consistent with the high sulfate concentrations observed in cores. The combined surface-drilled borehole/U-tube approach can provide a large amount of physical, chemical, and microbial data from the subpermafrost environment with few, controllable, sources of contamination. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  19. Hydrogeology, chemical and microbial activity measurement through deep permafrost

    Energy Technology Data Exchange (ETDEWEB)

    Stotler, R.L.; Frape, S.K.; Freifeld, B.M.; Holden, B.; Onstott, T.C.; Ruskeeniemi, T.; Chan, E.

    2010-04-01

    Little is known about hydrogeochemical conditions beneath thick permafrost, particularly in fractured crystalline rock, due to difficulty in accessing this environment. The purpose of this investigation was to develop methods to obtain physical, chemical, and microbial information about the subpermafrost environment from a surface-drilled borehole. Using a U-tube, gas and water samples were collected, along with temperature, pressure, and hydraulic conductivity measurements, 420 m below ground surface, within a 535 m long, angled borehole at High Lake, Nunavut, Canada, in an area with 460-m-thick permafrost. Piezometric head was well above the base of the permafrost, near land surface. Initial water samples were contaminated with drill fluid, with later samples <40% drill fluid. The salinity of the non-drill fluid component was <20,000 mg/L, had a Ca/Na ratio above 1, with {delta}{sup 18}O values {approx}5{per_thousand} lower than the local surface water. The fluid isotopic composition was affected by the permafrost-formation process. Nonbacteriogenic CH{sub 4} was present and the sample location was within methane hydrate stability field. Sampling lines froze before uncontaminated samples from the subpermafrost environment could be obtained, yet the available time to obtain water samples was extended compared to previous studies. Temperature measurements collected from a distributed temperature sensor indicated that this issue can be overcome easily in the future. The lack of methanogenic CH{sub 4} is consistent with the high sulfate concentrations observed in cores. The combined surface-drilled borehole/U-tube approach can provide a large amount of physical, chemical, and microbial data from the subpermafrost environment with few, controllable, sources of contamination.

  20. Monitoring an Induced Permafrost Warming Experiment Using ERT, Temperature, and NMR in Fairbanks, Alaska

    Science.gov (United States)

    Ulrich, C.; Ajo Franklin, J. B.; Ekblaw, I.; Lindsey, N.; Wagner, A. M.; Saari, S.; Daley, T. M.; Freifeld, B. M.

    2016-12-01

    As global temperatures continue to rise, permafrost landscapes will experience more rapid changes than other global climate zones. Permafrost thaw is a result of increased temperatures in arctic settings resulting in surface deformation and subsurface hydrology changes. From an engineering perspective, surface deformation poses a threat to the stability of existing infrastructure such as roads, utility piping, and building structures. Preemptively detecting or monitoring subsurface thaw dynamics presents a difficult challenge due to the long time scales as deformation occurs. Increased subsurface moisture content results from permafrost thaw of which electrical resistivity tomography (ERT), soil temperature, and nuclear magnetic resonance (NMR) are directly sensitive. In this experiment we evaluate spatial and temporal changes in subsurface permafrost conditions (moisture content and temperature) at a experimental heating plot in Fairbanks, AK. This study focuses on monitoring thaw signatures using multiple collocated electrical resistivity (ERT), borehole temperature, and borehole nuclear magnetic resonance (NMR) measurements. Timelapse ERT (sensitive to changes in moisture content) was inverted using collocated temperature and NMR to constrain ERT inversions. Subsurface thermal state was monitored with timelapse thermistors, sensitive to soil ice content. NMR was collected in multiple boreholes and is sensitive to changes in moisture content and pore scale distribution. As permafrost thaws more hydrogen, in the form of water, is available resulting in a changing NMR response. NMR requires the availability of liquid water in order to induce spin of the hydrogen molecule, hence, if frozen water molecules will be undetectable. In this study, the permafrost is poised close to 0oC and is mainly silt with small pore dimensions; this combination makes NMR particularly useful due to the possibility of sub-zero thaw conditions within the soil column. Overall this

  1. Permafrost Map of Alaska, USA, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of a geo-referenced digital map and attribute data derived from the publication 'Permafrost map of Alaska'. The map is presented at a scale of...

  2. Permafrost Meta-Omics and Climate Change

    DEFF Research Database (Denmark)

    Mackelprang, Rachel; Saleska, Scott R.; Jacobsen, Carsten Suhr

    2016-01-01

    from thawing permafrost regions. Analysis of nucleic acids and proteins taken directly from permafrost-associated soils has provided new insights into microbial communities and their functions in Arctic environments that are increasingly impacted by climate change. In this article we review current...... carbon produce carbon dioxide and other greenhouse gases, contributing substantially to climate change. Next-generation sequencing and other -omics technologies offer opportunities to discover the mechanisms by which microbial communities regulate the loss of carbon and the emission of greenhouse gases...... information from various molecular -omics studies on permafrost microbial ecology and explore the relevance of these insights to our current understanding of the dynamics of permafrost loss due to climate change....

  3. Relevance of mineral-organic associations in cryoturbated permafrost soils

    Science.gov (United States)

    Gentsch, Norman; Mikutta, Robert; Bárta, Jiří; Čapek, Petr; Gittel, Antje; Richter, Andreas; Šantrůčková, Hanna; Schnecker, Jörg; Shibistova, Olga; Urich, Tim; Wild, Birgit; Guggenberger, Georg

    2014-05-01

    Enhanced microbial decomposition of deep buried organic matter (OM) increase the release of CO2and CH4from high latitude ecosystems, thus being an uncertain but potentially crucial positive feedback to global warming. The role of soil minerals as stabilization agents of OM against microbial attack gain in importance as soon abiotic soil conditions will change in permafrost soils. We investigated changes in storage and turnover of soil organic carbon (OC) and total nitrogen (TN) associated with minerals in 27 cryoturbated permafrost soils from the west to the east Siberian Arctic. Furthermore, we studied the mineral composition and the potential of OM to interact with soil minerals via different binding mechanisms. Mineral-associated organic matter (MOM) was separated from particulate plant debris by density fractionation in sodium polytungstate (density cut-off 1.6 g cm-3). Their apparent 14C ages were determined by accelerator mass spectrometry and potential mineralization rates were analyzed in a 180 days incubation experiments at 5 and 15° C. The mineral composition was analyzed by X-ray diffraction and selective extractions. Desorption experiments (stepwise extraction with KCl and NaH2PO4) using the permafrost soils as well as reference soils from temperate regions (three Stagnolsols from Germany) were performed to study OM sorbed to mineral surfaces or complexed with polyvalent metal ions. The proportion of OC associated with minerals (MOC) ranged from 5.1 to 14.9 kg m-2 (average: 11.0 kg m-2), corresponding to ~55% from the total soil OC storage (average: 20.2 ± 8.0 kg m-2) in the first meter of the Cryosols. In contrast to temperate soils, where maximum MOC concentrations are present in topsoils, cambic, or spodic horizons, cryoturbation in permafrost soils leads to high MOC concentrations within the whole solum. Cryoturbated OM-rich pockets in the subsoil store 18% (2.0 ± 1.3 kg m-2) of the MOC while another 34% (3.8 ± 3.5 kg m-2) was located in the

  4. Permafrost and changing climate: the Russian perspective.

    Science.gov (United States)

    Anisimov, Oleg; Reneva, Svetlana

    2006-06-01

    The permafrost regions occupy about 25% of the Northern Hemisphere's terrestrial surface, and more than 60% of that of Russia. Warming, thawing, and degradation of permafrost have been observed in many locations in recent decades and are likely to accelerate in the future as a result of climatic change. Changes of permafrost have important implications for natural systems, humans, and the economy of the northern lands. Results from mathematical modeling indicate that by the mid-21st century, near-surface permafrost in the Northern Hemisphere may shrink by 15%-30%, leading to complete thawing of the frozen ground in the upper few meters, while elsewhere the depth of seasonal thawing may increase on average by 15%-25%, and by 50% or more in the northernmost locations. Such changes may shift the balance between the uptake and release of carbon in tundra and facilitate emission of greenhouse gases from the carbon-rich Arctic wetlands. Serious public concerns are associated with the effects that thawing permafrost may have on the infrastructure constructed on it. Climate-induced changes of permafrost properties are potentially detrimental to almost all structures in northern lands, and may render many of them unusable. Degradation of permafrost and ground settlement due to thermokarst may lead to dramatic distortions of terrain and to changes in hydrology and vegetation, and may lead ultimately to transformation of existing landforms. Recent studies indicate that nonclimatic factors, such as changes in vegetation and hydrology, may largely govern the response of permafrost to global warming. More studies are needed to better understand and quantify the effects of multiple factors in the changing northern environment.

  5. Why Permafrost Is Thawing, Not Melting

    Science.gov (United States)

    Grosse, Guido; Romanovsky, Vladimir; Nelson, Frederick E.; Brown, Jerry; Lewkowicz, Antoni G.

    2010-03-01

    As global climate change is becoming an increasingly important political and social issue, it is essential for the cryospheric and global change research communities to speak with a single voice when using basic terminology to communicate research results and describe underlying physical processes. Experienced science communicators have highlighted the importance of using the correct terms to communicate research results to the media and general public [e.g., Akasofu, 2008; Hassol, 2008]. The consequences of scientists using improper terminology are at best oversimplification, but they more likely involve misunderstandings of the facts by the public. A glaring example of scientifically incorrect terminology appearing frequently in scientific and public communication relates to reports on the degradation of permafrost. Numerous research papers have appeared in recent years, broadly echoed in the news media, describing the “melting of permafrost,” its effects in the Arctic, and its feedbacks on climate through the carbon cycle. Although permafrost researchers have attempted to distinguish between the appropriate term “permafrost thawing” and the erroneous “permafrost melting” [e.g., van Everdingen, 2005; French, 2002], the latter is still used widely. A Web-based search using the phrase “permafrost melting” reveals hundreds of occurrences, many from highly regarded news and scientific organizations, including Reuters, New Scientist, ABC, The Guardian, Discovery News, Smithsonian magazine, the National Science Foundation, and others.

  6. Degrading Discontinuous Permafrost Detected by Repeated Electrical Resistivity Tomography Surveys, Northwest Canada

    Science.gov (United States)

    Lewkowicz, A.; Holloway, J.

    2016-12-01

    Climate change is causing permafrost to warm rapidly in most of the Arctic. In subarctic regions where permafrost is discontinuous, however, rates of frozen ground warming are slower. This is because net positive heat fluxes at the surface of the ground and geothermal heat are transformed into latent heat associated with increases in soil unfrozen moisture content, especially in fine-grained soils at temperatures just below 0°C. At such sites, monitoring of temperatures in boreholes may be insufficient to track progressive change both because thaw may occur laterally, and because the slow alteration of temperature may be less than the accuracy of the instrumentation. Electrical Resistivity Tomography (ERT) surveys represent an alternative technique to monitor permafrost change because the electrical properties of soils alter significantly as their unfrozen moisture contents increase. We present results from multi-year studies in Yukon, northern British Columbia and the Northwest Territories where repeated ERT surveys using permanent or temporary electrode arrays reveal progressive thaw of thin permafrost at undisturbed sites in the boreal forest, and at sites affected by recent forest fire or changes in surface drainage. These field observations not only show the impact of climate and surface change on permafrost, they also demonstrate the efficacy of ERT as a means of monitoring sites where frost tables are too deep to be probed or where taliks have developed. We conclude that ERT surveys should be incorporated into international monitoring networks such as the Global Terrestrial Network for Permafrost since they can reveal progressive change at sites where ground temperatures, in contrast, suggest stable permafrost conditions.

  7. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    International Nuclear Information System (INIS)

    Cascoyne, M.

    2000-06-01

    Salt-rejection into the aqueous phase from permafrost growth ('aggradation') during the onset of cold-climate conditions in the Pleistocene period is a mechanism that could account for the presence of saline groundwaters in the Fennoscandian Shield. This report describes the results of a review of scientific literature on the subject of permafrost, to search for and evaluate information which may indicate whether this mechanism is feasible for sites such as Olkiluoto and Aespoe on the Baltic Sea coast. The geomorphological characteristics of permafrost (such as development of patterned ground, ice wedging, pingo growth) have been studied in detail in the literature and provide an understanding of the effects of pore water expulsion and saline water formation. Evidence of salt-rejection during permafrost aggradation is found in results of analyses of the chemical and isotopic compositions of water in pingos and open taliks published in North American, Chinese and Russian literature over the last fifty years. While most studies have concentrated on shallow permafrost in soils and sediments, deep-drilling by the oil and gas industry has shown that permafrost may extend both laterally and to considerable depth. For instance, permafrost on the north slope of Alaska is laterally continuous over an area of at least 1000 km 2 and is associated with fluids of salinities up to 130 g/L. Also, in northern Siberia, permafrost has been observed to depths of over 900 m. Saline waters are ubiquitous in coastal areas that are currently underlain by permafrost. However, it is not clear how much of the salinity has been produced by the freezing process and how much is simply due to leaching of saline soils and sediments by groundwaters and the presence of residual seawater in the sediments. Possible indicators of concentration by freezing include the presence of brines (i.e. waters of greater salinity than seawater), mineral precipitates (e.g. mirabilite) that are formed on freezing

  8. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    International Nuclear Information System (INIS)

    Gascoyne, M.

    2000-04-01

    Salt-rejection into the aqueous phase from permafrost growth during the onset of cold-climate conditions in the Pleistocene period is a mechanism that could account for the presence of saline groundwaters in the Fennoscandian Shield. This report describes the results of a review of scientific literature on the subject of permafrost, to search for and evaluate information which may indicate whether this mechanism is feasible for sites such as Olkiluoto and Aespoe on the Baltic Sea coast. The geomorphological characteristics of permafrost (such as development of patterned ground, ice wedging, pingo growth) have been studied in detail in the literature and provide an understanding of the effects of pore water expulsion and saline water formation. Evidence of salt-rejection during permafrost aggradation is found in results of analyses of the chemical and isotopic compositions of water in pingos and open taliks published in North American, Chinese and Russian literature over the last fifty years. While most studies have concentrated on shallow permafrost in soils and sediments, deep-drilling by the oil and gas industry has shown that permafrost may extend both laterally and to considerable depth. For instance, permafrost on the north slope of Alaska is laterally continuous over an area of at least 1000 km 2 and is associated with fluids of salinities up to 130 g/L. Also, in northern Siberia, permafrost has been observed to depths of over 900 m. Saline waters are ubiquitous in coastal areas that are currently underlain by permafrost. However, it is not clear how much of the salinity has been produced by the freezing process and how much is simply due to leaching of saline soils and sediments by ground- waters and the presence of residual seawater in the sediments. Possible indicators of concentration by freezing include the presence of brines (i.e.waters of greater salinity than seawater), mineral precipitates (e.g. mirabilite) that are formed on freezing of seawater

  9. Transitory storage plants for hazardous waste, mapping and risk analysis; Mellanlager foer farligt avfall. Kartlaeggning och riskbedoemning

    Energy Technology Data Exchange (ETDEWEB)

    Stenstroem, M.; Svensson, Indra; Eriksson, Haakan; Liljedahl, B.; Scott, Aa.

    1997-12-01

    The Defence Research Establishment has, at the request of the National Rescue Service Board, studied risks in connection with transitory storage plants of hazardous waste. The aim of this study has been to map out, describe and analyse risks to human beings and to the environment at, and in the neighbourhood of, transitory storage plants in Sweden and, too, make a preliminary judgement on the extent of the problem. Altogether, the study is based on information about 121 transitory storage plants for hazardous waste in 21 countries and 74 municipalities, information of a highly detailed nature as well as of a less detailed one. In order to be able to form an opinion of possible risks at transitory storage plants, the reader is offered an account of the various stages of analysis and synthesis as follows: (1) Description of transitory storage of hazardous waste as socio technical system. (2) Description of possible events. (3) Description of possible effects on human beings and on the environment. (4) Conclusion. As far as the extent of the problem is concerned, we believe that the risk of serious accidents at transitory storage plants of hazardous waste is statistically small. When compared to other risks present in the society, accidents at transitory storage plants might be considered to be a problem not worth mentioning, but still, the prerequisites are there and the effects on human beings and on the environment can be extensive in a worst case. Therefore, there is every reason to seek further knowledge for reasons of risk and security at transitory storage plants of hazardous waste. One subject to enter deeply into could be that of how various actors cooperate when it comes to security at transitory storage plants. 26 refs.

  10. Holocene Development of Subarctic Permafrost Peatlands in Finnmark, Northern Norway

    Science.gov (United States)

    Sannel, B.; Axelsson, P.; Kjellman, S.; Etzelmuller, B.; Westermann, S.

    2017-12-01

    Subarctic permafrost peatlands have acted as important carbon sinks throughout the Holocene. An improved knowledge of peat properties and sensitivity to past climate changes in these environments can help us better predict future responses under warmer climatic conditions, and associated permafrost carbon feedbacks. In this study analyses of plant macrofossils, bulk density, organic, carbon and nitrogen content, and AMS radiocarbon dating have been performed for four profiles collected from peat plateaus in Finnmark, northern Norway. Preliminary results suggest that peatland development started around 9800-9200 cal yr BP at the two continental sites, Suossjavri and Iskoras. Here, the long-term net carbon accumulation rates are around 12-17 gC m-2 yr-1, and the total carbon storage c. 113-156 kgC m-2. The other two sites, Lakselv and Karlebotn, are located in maritime settings close to the coast where there has been a time lag between deglaciation of the Fennoscandian Ice Sheet and emergence of land by isostatic uplift. At these sites peatland inception begun around 6200-5200 cal yr BP, and the carbon accumulation rates are c. 7-12 gC m-2 yr-1. Because of a shorter time period available for peat accumulation the carbon storage at these sites is lower, around 56-64 kgC m-2. All four peatlands developed as wet fens, and have remained permafrost-free throughout most of the Holocene. Permafrost aggradation, causing frost heave and a shift in the vegetation assemblage from wet fen to dry bog species, probably did not occur until during the onset of the Little Ice Age c. 1000-800 cal yr BP (at Iskoras and Karlebotn) or even later, around 100 cal yr BP (at Suossjavri and Lakselv). If the permafrost thaws in a future warmer climate, the carbon that has been stored in the frozen peat since the Little Ice Age can become available for decomposition and be emitted to the atmosphere either as carbon dioxide from expanding active layers or as methane from thermokarst lakes and

  11. Horizontal-to-vertical spectral ratio variability in the presence of permafrost

    Science.gov (United States)

    Kula, Damian; Olszewska, Dorota; Dobiński, Wojciech; Glazer, Michał

    2018-03-01

    Due to fluctuations in the thickness of the permafrost active layer, there exists a seasonal seismic impedance contrast in the permafrost table. The horizontal-to-vertical spectral ratio (HVSR) method is commonly used to estimate the resonant frequency of sedimentary layers on top of bedrock. Results obtained using this method are thought to be stable in time. The aim of the study is to verify whether seasonal variability in the permafrost active layer influences the results of the HVSR method. The research area lies in the direct vicinity of the Polish Polar Station Hornsund, which is located in Southern Spitsbergen, Svalbard. Velocity models of the subsurface are obtained using the HVSR method, which are juxtaposed with electrical resistivity tomography profiles conducted near the seismic station. Survey results indicate that the active layer of permafrost has a major influence on the high-frequency section of the HVSR results. In addition, the depth of the permafrost table inferred using the HVSR method is comparable to the depth visible in ERT results. This study proves that, in certain conditions, the HVSR method results vary seasonally, which must be taken into account in their interpretation.

  12. Thawing of permafrost may disturb historic cattle burial grounds in East Siberia

    Directory of Open Access Journals (Sweden)

    Boris A. Revich

    2011-11-01

    Full Text Available Climate warming in the Arctic may increase the risk of zoonoses due to expansion of vector habitats, improved chances of vector survival during winter, and permafrost degradation. Monitoring of soil temperatures at Siberian cryology control stations since 1970 showed correlations between air temperatures and the depth of permafrost layer that thawed during summer season. Between 1900s and 1980s, the temperature of surface layer of permafrost increased by 2–4°C; and a further increase of 3°C is expected. Frequent outbreaks of anthrax caused death of 1.5 million deer in Russian North between 1897 and 1925. Anthrax among people or cattle has been reported in 29,000 settlements of the Russian North, including more than 200 Yakutia settlements, which are located near the burial grounds of cattle that died from anthrax. Statistically significant positive trends in annual average temperatures were established in 8 out of 17 administrative districts of Yakutia for which sufficient meteorological data were available. At present, it is not known whether further warming of the permafrost will lead to the release of viable anthrax organisms. Nevertheless, we suggest that it would be prudent to undertake careful monitoring of permafrost conditions in all areas where an anthrax outbreak had occurred in the past.

  13. Air duct systems for roadway stabilization over permafrost areas

    Science.gov (United States)

    1984-03-01

    In the discontinuous permafrost regions of Alaska it is not always possible to route roads over non-permafrost ground. For areas like these, highway engineers face a tremendous design challenge in attempting to provide a stable roadway base. Several ...

  14. Circumpolar Active-Layer Permafrost System (CAPS), Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Circumpolar Active-Layer Permafrost System (CAPS) contains over 100 data sets pertaining to permafrost and frozen ground topics. It also contains detailed...

  15. Predicting bulk powder flow dynamics in a continuous mixer operating in transitory regimes

    OpenAIRE

    Ammarcha , Chawki; Gatumel , Cendrine; Dirion , Jean-Louis; Cabassud , Michel; Mizonov , Vadim; Berthiaux , Henri

    2012-01-01

    International audience; Over recent years there has been increasing interest in continuous powder mixing processes, due mainly to the development of on-line measurement techniques. However, our understanding of these processes remains limited, particularly with regard to their flow and mixing dynamics. In the present work, we study the behaviour of a pilot-scale continuous mixer during transitory regimes, in terms of hold-up weight and outflow changes. We present and discuss experimental resu...

  16. Landscape effects of wildfire on permafrost distribution in interior Alaska derived from remote sensing

    Science.gov (United States)

    Brown, Dana R. N.; Jorgenson, M. Torre; Kielland, Knut; Verbyla, David L.; Prakash, Anupma; Koch, Joshua C.

    2016-01-01

    drier surface soils. Burn severity also influenced plant community composition, which was tightly linked to soil temperature and moisture. Overall, interactions between burn severity, topography, and vegetation appear to control the distribution of near-surface permafrost and associated drainage conditions after disturbance.

  17. Mathematical modeling of heat transfer problems in the permafrost

    Science.gov (United States)

    Gornov, V. F.; Stepanov, S. P.; Vasilyeva, M. V.; Vasilyev, V. I.

    2014-11-01

    In this work we present results of numerical simulation of three-dimensional temperature fields in soils for various applied problems: the railway line in the conditions of permafrost for different geometries, the horizontal tunnel underground storage and greenhouses of various designs in the Far North. Mathematical model of the process is described by a nonstationary heat equation with phase transitions of pore water. The numerical realization of the problem is based on the finite element method using a library of scientific computing FEniCS. For numerical calculations we use high-performance computing systems.

  18. Larval development with transitory epidermis in Paranemertes peregrina and other hoplonemerteans.

    Science.gov (United States)

    Maslakova, Svetlana A; von Döhren, Jörn

    2009-06-01

    We describe development of the hoplonemertean Paranemertes peregrina from fertilization to juvenile, using light, confocal, and electron microscopy. We discovered that the uniformly ciliated lecithotrophic larva of this species has a transitory epidermis, which is gradually replaced by the definitive epidermis during the course of planktonic development. The approximately 90 large multiciliated cleavage-arrested cells of the transitory larval epidermis become separated from each other by intercalating cells of the definitive epidermis, then gradually diminish in size and disappear more or less simultaneously. Rudiments of all major adult structures-the gut, proboscis, cerebral ganglia, lateral nerve cords, and cerebral organs-are already present in 4-day-old larvae. Replacement of the epidermis is the only overt metamorphic transformation of larval tissue; larval structures otherwise prefigure the juvenile body, which is complete in about 10 days at 7-10 degrees C. Our findings on development of digestive system, nervous system, and proboscis differ in several ways from previous descriptions of hoplonemertean development. We report development with transitory epidermis in two other species, review evidence from the literature, and suggest that this developmental type is the rule for hoplonemerteans. The hoplonemertean planuliform larva is fundamentally different both from the pilidium larva of the sister group to the Hoplonemertea, the Pilidiophora, and from the hidden trochophore of palaeonemerteans. We discuss the possible function and homology of the larval epidermis in development of other nemerteans and spiralians in general.

  19. Role of cell differentiation in high tolerance by prokaryotes of long-term preservation in permafrost

    Science.gov (United States)

    Soina, V. S.; Vorobyova, E. A.

    The effect of low temperature on the cell structure of bacteria isolated from permafrost results in structural changes leading to cell differentiation into types of resting cells rangign from spores showing a high endogenous dormancy to typical ``dormant'' cells of non-spore-forming bacteria showing exogenous dormancy, which is considered to be less highly resistant to extreme conditions in laboratory experiments. In permafrost, dormant cells of non-spore-forming bacteria may demonstrate considerable resistance to long-term freezing and as a result a higher survival level than spore-forming bacteria.

  20. Evaluating permafrost thaw vulnerabilities and hydrologic impacts in boreal Alaska (USA) watersheds using field data and cryohydrogeologic modeling

    Science.gov (United States)

    Walvoord, M. A.; Voss, C.; Ebel, B. A.; Minsley, B. J.

    2017-12-01

    Permafrost environments undergo changes in hydraulic, thermal, chemical, and mechanical subsurface properties upon thaw. These property changes must be considered in addition to alterations in hydrologic, thermal, and topographic boundary conditions when evaluating shifts in the movement and storage of water in arctic and sub-arctic boreal regions. Advances have been made in the last several years with respect to multiscale geophysical characterization of the subsurface and coupled fluid and energy transport modeling of permafrost systems. Ongoing efforts are presented that integrate field data with cryohydrogeologic modeling to better understand and anticipate changes in subsurface water resources, fluxes, and flowpaths caused by climate warming and permafrost thawing. Analyses are based on field data from several sites in interior Alaska (USA) that span a broad north-south transition from continuous to discontinuous permafrost. These data include soil hydraulic and thermal properties and shallow permafrost distribution. The data guide coupled fluid and energy flow simulations that incorporate porewater liquid/ice phase change and the accompanying modifications in hydraulic and thermal subsurface properties. Simulations are designed to assess conditions conducive to active layer thickening and talik development, both of which are expected to affect groundwater storage and flow. Model results provide a framework for identifying factors that control the rates of permafrost thaw and associated hydrologic responses, which in turn influence the fate and transport of carbon.

  1. Potential remobilization of belowground permafrost carbon under future global warming

    Science.gov (United States)

    P. Kuhry; E. Dorrepaal; G. Hugelius; E.A.G. Schuur; C. Tarnocai

    2010-01-01

    Research on permafrost carbon has dramatically increased in the past few years. A new estimate of 1672 Pg C of belowground organic carbon in the northern circumpolar permafrost region more than doubles the previous value and highlights the potential role of permafrost carbon in the Earth System. Uncertainties in this new estimate remain due to relatively few available...

  2. Vulnerability and feedbacks of permafrost to climate change

    Science.gov (United States)

    Guido Grosse; Vladimir Romanovsky; Torre Jorgenson; Katey Walter Anthony; Jerry Brown; Pier Paul Overduin; Alfred. Wegener

    2011-01-01

    The effects of permafrost degradation on terrestrial and offshore environments in polar regions and on the Earth's atmosphere are significant. Field-based observations, remote sensing, and modeling document regional warming and thawing of permafrost. However, major research questions regarding vulnerability of permafrost to thawing, the projected decline in...

  3. Transit-Oriented Development and Ports: National Analysis across the United States and a Case Study of New Orleans

    Science.gov (United States)

    2017-11-01

    The aim of this study is to examine the extent that freight and passenger transportation planning overlap within the context of transit-oriented developments (TODs) near ports. This study also includes a case study of New Orleans. Research questions ...

  4. Simulation of Streamflow in a Discontinuous Permafrost Environment Using a Modified First-order, Nonlinear Rainfall-runoff Model

    Science.gov (United States)

    Bolton, W. R.; Hinzman, L. D.

    2009-12-01

    The sub-arctic environment can be characterized by being located in the zone of discontinuous permafrost. Although the distribution of permafrost in this region is specific, it dominates the response of many of the hydrologic processes including stream flow, soil moisture dynamics, and water storage processes. In areas underlain by permafrost, ice-rich conditions at the permafrost table inhibit surface water percolation to the deep subsurface soils, resulting in an increased runoff generation generation during precipitation events, decreased baseflow between precipitation events, and relatively wetter soils compared to permafrost-free areas. Over the course of a summer season, the thawing of the active layer (the thin soil layer about the permafrost that seasonally freezes and thaws) increases the potential water holding capacity of the soil, resulting in a decreasing surface water contribution during precipitation events and a steadily increasing baseflow contribution between precipitation events. Simulation of stream flow in this region is challenging due to the rapidly changing thermal (permafrost versus non-permafrost, active layer development) and hydraulic (hydraulic conductivity and soil storage capacity) conditions in both time and space (x, y, and z-dimensions). Many of the factors that have a control on both permafrost distribution and the thawing/freezing of active layer (such as soil material, soil moisture, and ice content) are not easily quantified at scales beyond the point measurement. In this study, these issues are addressed through streamflow analysis - the only hydrologic process that is easily measured at the basin scale. Following the general procedure outlined in Kirchner (2008), a simple rainfall-runoff model was applied to three small head-water basins of varying permafrost coverage. A simple, first-order, non-linear differential equation that describes the storage-discharge relationship were derived from three years of stream flow data

  5. Frozen Stiff: Cartographic Design and Permafrost Mapping

    Science.gov (United States)

    Nelson, F. E.; Li, J.; Nyland, K. E.

    2016-12-01

    Maps are the primary vehicle used to communicate geographical relationships. Ironically, interest in the formal practice of cartography, the art and science of geographic visualization, has fallen significantly during a period when the sophistication and availability of GIS software has increased dramatically. Although the number of geographically oriented permafrost studies has increased significantly in recent years, little discussion about competing visualization strategies, map accuracy, and the psychophysical impact of cartographic design is evident in geocryological literature. Failure to use the full potential of the tools and techniques that contemporary cartographic and spatial-analytic theory makes possible affects our ability to effectively and accurately communicate the impacts and hazards associated with thawing permafrost, particularly in the context of global climate change. This presentation examines recent permafrost studies involving primarily small-scale (large area) mapping, and suggests cartographic strategies for rectifying existing problems.

  6. New insights in permafrost modelling

    Science.gov (United States)

    Tubini, Niccolò; Serafin, Francesco; Gruber, Stephan; Casulli, Vincenzo; Rigon, Riccardo

    2017-04-01

    Simulating freezing soil has ignored for long time in mainstream surface hydrology. However, it has indubitably a large influence on soil infiltrability and an even larger influence on the soil energy budget, and, over large spatial scales, a considerable feedback on climate. The topic is difficult because it involves concepts of disequilibrium Thermodynamics and also because, once solved the theoretical problem, integration of the resulting partial differential equations in a robust manner, is not trivial at all. In this abstract, we are presenting a new algorithm to estimate the water and energy budget in freezing soils. The first step is a derivation of a new equation for freezing soil mass budget (called generalized Richards equation) based on the freezing equals drying hypothesis (Miller 1965). The second step is the re-derivation of the energy budget. Finally there is the application of new techniques based on the double nested Newton algorithm (Casulli and Zanolli, 2010) to integrate the coupled equations. Some examples of the freezing dynamics and comparison with the Dall'Amico et al. (2011) algorithm are also shown. References Casulli, V., & Zanolli,P. (2010). A nested newton-type algorithm for finite colume methods solving Richards' equation in mixed form. SIAM J. SCI. Comput., 32(4), 2225-2273. Dall'Amico, M., Endrizzi, S., Gruber, S., & Rigon, R. (2011). A robust and energy-conserving model of freezing variably-saturated soil. The Cryosphere, 5(2), 469-484. http://doi.org/10.5194/tc-5-469-2011 Miller, R.: Phase equilibria and soil freezing, in: Permafrost: Proceedings of the Second International Conference. Washington DC: National Academy of Science-National Research Council, 287, 193-197, 1965.

  7. Climate change and the permafrost carbon feedback

    Science.gov (United States)

    Schuur, E.A.G.; McGuire, A. David; Schädel, C.; Grosse, G.; Harden, J.W.; Hayes, D.J.; Hugelius, G.; Koven, C.D.; Kuhry, P.; Lawrence, D.M.; Natali, Susan M.; Olefeldt, David; Romanovsky, V.E.; Schaefer, K.; Turetsky, M.R.; Treat, C.C.; Vonk, J.E.

    2015-01-01

    Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emission from these regions and their impact on climate change remain uncertain. Here we find that current evidence suggests a gradual and prolonged release of greenhouse gas emissions in a warming climate and present a research strategy with which to target poorly understood aspects of permafrost carbon dynamics.

  8. Climate change and the permafrost carbon feedback.

    Science.gov (United States)

    Schuur, E A G; McGuire, A D; Schädel, C; Grosse, G; Harden, J W; Hayes, D J; Hugelius, G; Koven, C D; Kuhry, P; Lawrence, D M; Natali, S M; Olefeldt, D; Romanovsky, V E; Schaefer, K; Turetsky, M R; Treat, C C; Vonk, J E

    2015-04-09

    Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emission from these regions and their impact on climate change remain uncertain. Here we find that current evidence suggests a gradual and prolonged release of greenhouse gas emissions in a warming climate and present a research strategy with which to target poorly understood aspects of permafrost carbon dynamics.

  9. Responses of alpine grassland on Qinghai–Tibetan plateau to climate warming and permafrost degradation: a modeling perspective

    International Nuclear Information System (INIS)

    Yi, Shuhua; Wang, Xiaoyun; Qin, Yu; Ding, Yongjian; Xiang, Bo

    2014-01-01

    Permafrost plays a critical role in soil hydrology. Thus, the degradation of permafrost under warming climate conditions may affect the alpine grassland ecosystem on the Qinghai–Tibetan Plateau. Previous space-for-time studies using plot and basin scales have reached contradictory conclusions. In this study, we applied a process-based ecosystem model (DOS-TEM) with a state-of-the-art permafrost hydrology scheme to examine this issue. Our results showed that 1) the DOS-TEM model could properly simulate the responses of soil thermal and hydrological dynamics and of ecosystem dynamics to climate warming and spatial differences in precipitation; 2) the simulated results were consistent with plot-scale studies showing that warming caused an increase in maximum unfrozen thickness, a reduction in vegetation and soil carbon pools as a whole, and decreases in soil water content, net primary production, and heterotrophic respiration; and 3) the simulated results were also consistent with basin-scale studies showing that the ecosystem responses to warming were different in regions with different combinations of water and energy constraints. Permafrost prevents water from draining into water reservoirs. However, the degradation of permafrost in response to warming is a long-term process that also enhances evapotranspiration. Thus, the degradation of the alpine grassland ecosystem on the Qinghai–Tibetan Plateau (releasing carbon) cannot be mainly attributed to the disappearing waterproofing function of permafrost. (letter)

  10. Precarious work among young Danish employees- a permanent or transitory condition?

    DEFF Research Database (Denmark)

    Nielsen, Mette Lykke; Dyreborg, Johnny; Lipscomb, Hester

    2018-01-01

    trade captured in 66 interviews. We investigate whether precariousness is related to being young and employed in general, or if specific categories of young employees become particularly vulnerable in this social and economic transformation to adulthood. We explore how young employees describe...... their position and how they position themselves in relation to uncertainty and vulnerability at work. We conclude that precarious work is not, in fact, simply a characteristic of young employees’ work as such, but rather it is related to their position in the labor market and the type of jobs in which......There is broad agreement that precarious work is a growing problem, and that it is highly prevalent among young employees. The aim of this paper is to examine the discursive representations of precarious work among young employees aged 18-24 in the healthcare sector, the metal industry and retail...

  11. Canadian Geothermal Data Collection: Deep permafrost temperatures and thickness of permafrost, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision temperature measurements have been made in some 150 deep wells and holes drilled in the course of natural resource exploration in the permafrost regions of...

  12. Bioavailability of soil organic matter and microbial community dynamics upon permafrost thaw.

    Science.gov (United States)

    Coolen, Marco J L; van de Giessen, Jeroen; Zhu, Elizabeth Y; Wuchter, Cornelia

    2011-08-01

    Amplified Arctic warming could thaw 25% of the permafrost area by 2100, exposing vast amounts of currently fixed organic carbon to microbially mediated decomposition and release of greenhouse gasses through soil organic matter (SOM) respiration. We performed time-series incubation experiments with Holocene permafrost soils at 4°C for up to 11 days to determine changes in exoenzyme activities (EEAs) (i.e. phosphatase, β-glucosidase, aminopeptidase) as a measure for the bioavailability of SOM in response to permafrost thaw. We also profiled SSU rRNA transcripts to follow the qualitative and quantitative changes in viable prokaryotes and eukaryotes during incubation. EEA, amount of rRNA transcripts and microbial community structures differed substantially between the various soil intervals in response to thaw: after 11 days of incubation, the active layer became slightly depleted in C and P and harboured bacterial phyla indicative of more oligotrophic conditions (Acidobacteria). A fast response in phosphatase and β-glucosidase upon thaw, and a predominance of active copiotrophic Bacteroidetes, showed that the upper permafrost plate serves as storage of easily degradable carbon derived from the overlying thawed active layer during summer. EEA profiles and microbial community dynamics furthermore suggest that the deeper and older permafrost intervals mainly contain recalcitrant SOM, and that extracellular soil-bound exoenzymes play a role in the initial cleavage of biopolymers, which could kick-start microbial growth upon thaw. Basidiomycetous fungi and Candidate Subdivision OP5 bacteria were the first to respond in freshly thawed deeper permafrost intervals, and might play an important role in the decomposition of recalcitrant SOM to release more labile substrates to support the major bacterial phyla (β-Proteobacteria, Actinobacteria, Firmicutes), which predominated thereafter. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  13. Strategy of valid 14C dates choice in syngenetic permafrost

    Science.gov (United States)

    Vasil'chuk, Y. K.; Vasil'chuk, A. C.

    2014-11-01

    The main problem of radiocarbon dating within permafrost is the uncertain reliability of the 14C dates. Syngenetic sediments contain allochthonous organic deposit that originated at a distance from its present position. Due to the very good preservation of organic materials in permafrost conditions and numerous re-burials of the fossils from ancient deposits into younger ones the dates could be both younger and older than the true age of dated material. The strategy for the most authentic radiocarbon date selection for dating of syncryogenic sediments is considered taking into account the fluvial origin of the syngenetic sediments. The re-deposition of organic material is discussed in terms of cyclic syncryogenic sedimentation and also the possible re-deposition of organic material in subaerial-subaqueous conditions. The advantages and the complications of dating organic micro-inclusions from ice wedges by the accelerator mass spectrometry (AMS) method are discussed applying to true age of dated material search. Radiocarbon dates of different organic materials from the same samples are compared. The younger age of the yedoma from cross-sections of Duvanny Yar in Kolyma River and Mamontova Khayata in the mouth of Lena River is substantiated due to the principle of the choice of the youngest 14C date from the set.

  14. Permafrost a změny klimatu

    Czech Academy of Sciences Publication Activity Database

    Mikuláš, Radek

    2005-01-01

    Roč. 84, č. 6 (2005), s. 345-347 ISSN 0042-4544 R&D Projects: GA AV ČR(CZ) KSK3046108 Keywords : permafrost * climate change * Holocene Subject RIV: DB - Geology ; Mineralogy http://www.vesmir.cz/clanek.php3?CID=6314

  15. Permafrost on tropical Maunakea volcano, Hawaii

    Science.gov (United States)

    Leopold, Matthias; Schorghofer, Norbert; Yoshikawa, Kenji

    2017-04-01

    Maunakea volcano on Hawaii Island is known for one of the most unusual occurrences of sporadic permafrost. It was first documented in two cinder cone craters in the 1970's near the summit of the mountain where mean annual air temperatures are currently around +4 deg. Our study investigates the current state of this permafrost, by acquiring multi-year ground temperature data and by applying electrical resistivity tomography and ground penetrating radar techniques along several survey lines. Both of the previously known ice bodies still exist, but one of them has dramatically shrunken in volume. Based on current warming trends it might disappear soon. In addition insolation modelling, temperature probing, and geomorphological indicators were used to prospect for additional permafrost bodies on the wider summit region, however, none was found. It seems that permafrost preferentially appears in the interiors of cinder cones, even though there are exterior slopes that receive less sunlight annually. We hypothesis that snow cover with its high albedo, and a layer of coarse boulders where cold air settles in the pore space during calm nights, play a significant role in cooling the subsurface. Due to the relatively simple setting, the study site is an ideal model system and may also serve as an analogue to Mars.

  16. Climate change and the permafrost carbon feedback

    NARCIS (Netherlands)

    Schuur, E. A G; McGuire, A. D.; Schädel, C.; Grosse, G.; Harden, J. W.; Hayes, D. J.; Hugelius, G.; Koven, C. D.; Kuhry, P.; Lawrence, D. M.; Natali, S. M.; Olefeldt, D.; Romanovsky, V. E.; Schaefer, K.; Turetsky, M. R.; Treat, C. C.; Vonk, J. E.|info:eu-repo/dai/nl/370832833

    2015-01-01

    Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This

  17. International Field School on Permafrost: Yenisei, Russian Federation - 2013

    Science.gov (United States)

    Nyland, K. E.; Streletskiy, D. A.; Grebenets, V. I.

    2013-12-01

    The International Field School on Permafrost was established in Russia as part of International Polar Year activities. The first course was offered in 2007 in Northwestern Siberia and attracted students from Russia, Germany, and the United States. Over the past seven years undergraduate and graduate students representing eight different countries in North America, Europe, and Asia have participated in the field school. This annual summer field course visits different regions of the Russian Arctic each year, but the three course foci remain consistent, which are to make in depth examinations of, 1) natural permafrost characteristics and conditions, 2) field techniques and applications, and 3) engineering practices and construction on permafrost. During these field courses students participate in excursions to local museums and exhibitions, meet with representatives from local administrations, mining and construction industries, and learn field techniques for complex permafrost investigations, including landscape and soil descriptions, temperature monitoring, active-layer measurements, cryostratigraphy, and more. During these courses students attend an evening lecture series by their professors and also give presentations on various regionally oriented topics of interest, such as the local geology, climate, or historical development of the region. This presentation will relate this summer's (July 2013) field course which took place in the Yenisei River region of central Siberia. The course took place along a bioclimatic transect from south to north along the Yenisei River and featured extended stays in the cities of Igarka and Noril'sk. This year's students (undergraduate, masters, and one PhD student) represented universities in the United States, Canada, and the Russian Federation. The organization of this course was accomplished through the cooperation of The George Washington University's Department of Geography and the Lomonosov Moscow State University

  18. Ground penetrating radar estimates of permafrost ice wedge depth

    Science.gov (United States)

    Parsekian, A.; Slater, L. D.; Nolan, J. T.; Grosse, G.; Walter Anthony, K. M.

    2013-12-01

    Vertical ground ice wedges associated with polygonal patterning in permafrost environments form due to frost cracking of soils under harsh winter conditions and subsequent infilling of cracks with snow melt water. Ice wedge polygon patterns have implications for lowland geomorphology, hydrology, and vulnerability of permafrost to thaw. Ice wedge dimensions may exceed two meters width at the surface and several meters depth, however few studies have addressed the question of ice wedge depth due to challenges related to measuring the vertical dimension below the ground. Vertical exposures where ice wedges maybe observed are limited to rapidly retreating lake, river, and coastal bluffs. Coring though the ice wedges to determine vertical extent is possible, however that approach is time consuming and labor intensive. Many geophysical investigations have noted signal anomalies related to the presence of ice wedges, but no reliable method for extracting wedge dimensions from geophysical data has been yet proposed. Here we present new evidence that ground penetrating radar (GPR) may be a viable method for estimating ice wedge depth. We present three new perspectives on processing GPR data collected over ice wedges that show considerable promise for use as a fast, cost effective method for evaluating ice wedge depth. Our novel approaches include 1) a simple frequency-domain analysis, 2) an S-transform frequency domain analysis and 3) an analysis of the returned signal power as a radar cross section (RCS) treating subsurface ice wedges as dihedral corner retro-reflectors. Our methods are demonstrated and validated using finite-difference time domain FDTD) GPR forward models of synthetic idealized ice wedges and field data from permafrost sites in Alaska. Our results indicate that frequency domain and signal power data provide information that is easier to extract from raw GPR data than similar information in the time domain. We also show that we can simplify the problem by

  19. Permafrost and Periglacial Geomorphology of Western Taymyr (PPG), Russia

    Science.gov (United States)

    Streletskaya, I.

    2009-04-01

    acquired field-work skills (describing boreholes and transverse sections, defining ice fraction, and collecting and archiving of samples), as well as laboratory skills on collected materials (evaluation of solid natural moisture content, herborization and sorting of samples). Samples of ice, snow and ground and paleofauna were collected for chemical, isotopic, microfaunistical, granulometrical, radiocarbon, paleomagnetic analysis. Contemporary cryogenic processes of Western Taymyr coastal zone were also explored, in particular coastal dynamics, ice wedges, thermokarst, etc. The obtained data will enable an estimation of the present-day situation in Western Taimyr permafrost zone and the reconstruction of the conditions of permafrost evolution and formation in the past. The course was funded by Lomonosov Moscow State University, All-Russian Research Institute of Geology and Mineral resources of Ocean RAS (VNIIOkeangeologia), ConocoPhillips Russia Inc. and the Earth Cryosphere Institute SB RAS.

  20. The transitory and permanent volatility of oil prices: What implications are there for the US industrial production?

    International Nuclear Information System (INIS)

    Ali Ahmed, Huson Joher; Bashar, Omar H.M.N.; Wadud, I.K.M. Mokhtarul

    2012-01-01

    Highlights: ► This study examines the impact of oil price uncertainty on the US industrial production (IPI). ► The transitory component of the oil price volatility has an adverse impact on the US IPI. ► The transitory oil price volatility induces higher volatility in CPI, commodity prices and IPI. -- Abstract: This study examines the impact of oil price uncertainty on the US industrial production by decomposing oil price volatility into permanent and transitory components. The decompositions provide important evidence on sources and asymmetric effects of oil price volatility. To estimate the component structure of volatility and to analyse the dynamic impacts of the volatility components, the study uses a threshold based CGARCH and VAR modelling over a period from 1980 to 2010 for the US economy. The CGARCH model estimates show significant asymmetric effect of oil price shock on the transitory oil price volatility. Dynamic impulse response functions obtained from the estimated VAR models reveal that there is a significant and prolonged dampening impact of increased transitory oil price volatility on industrial production. The results also suggest that shocks to transitory component induce increased volatility in the general price level and non-fuel commodity prices in the US. Variance decomposition analysis reconfirms that the transitory volatility is the second most important factor to explain the variance of industrial production. These results provide additional insights on the sources of oil price uncertainty and point to the need to direct US energy policies towards stabilising short-term uncertainties in oil prices.

  1. Modelling high Arctic deep permafrost temperature sensitivity in Northeast Greenland based on experimental and field observations

    Science.gov (United States)

    Rasmussen, Laura Helene; Zhang, Wenxin; Hollesen, Jørgen; Cable, Stefanie; Hvidtfeldt Christiansen, Hanne; Jansson, Per-Erik; Elberling, Bo

    2017-04-01

    Permafrost affected areas in Greenland are expected to experience a marked temperature increase within decades. Most studies have considered near-surface permafrost sensitivity, whereas permafrost temperatures below the depths of zero annual amplitude is less studied despite being closely related to changes in near-surface conditions, such as changes in active layer thermal properties, soil moisture and snow depth. In this study, we measured the sensitivity of thermal conductivity (TC) to gravimetric water content (GWC) in frozen and thawed permafrost sediments from fine-sandy and gravelly deltaic and fine-sandy alluvial deposits in the Zackenberg valley, NE Greenland. We further calibrated a coupled heat and water transfer model, the "CoupModel", for one central delta sediment site with average snow depth and further forced it with meteorology from a nearby delta sediment site with a topographic snow accumulation. With the calibrated model, we simulated deep permafrost thermal dynamics in four 20-year scenarios with changes in surface temperature and active layer (AL) soil moisture: a) 3 °C warming and AL water table at 0.5 m depth; b) 3 °C warming and AL water table at 0.1 m depth; c) 6 °C warming and AL water table at 0.5 m depth and d) 6 °C warming and AL water table at 0.1 m depth. Our results indicate that frozen sediments have higher TC than thawed sediments. All sediments show a positive linear relation between TC and soil moisture when frozen, and a logarithmic one when thawed. Gravelly delta sediments were highly sensitive, but never reached above 12 % GWC, indicating a field effect of water retention capacity. Alluvial sediments are less sensitive to soil moisture than deltaic (fine and coarse) sediments, indicating the importance of unfrozen water in frozen sediment. The deltaic site with snow accumulation had 1 °C higher mean annual ground temperature than the average snow depth site. Permafrost temperature at the depth of 18 m increased with 1

  2. Subsidence from an artificial permafrost warming experiment.

    Science.gov (United States)

    Gelvin, A.; Wagner, A. M.; Lindsey, N.; Dou, S.; Martin, E. R.; Ekblaw, I.; Ulrich, C.; James, S. R.; Freifeld, B. M.; Daley, T. M.; Saari, S.; Ajo Franklin, J. B.

    2017-12-01

    Using fiber optic sensing technologies (seismic, strain, and temperature) we installed a geophysical detection system to predict thaw subsidence in Fairbanks, Alaska, United States. Approximately 5 km of fiber optic was buried in shallow trenches (20 cm depth), in an area with discontinuous permafrost, where the top of the permafrost is approximately 4 - 4.5m below the surface. The thaw subsidence was enforced by 122 60-Watt vertical heaters installed over a 140 m2 area where seismic, strain, and temperature were continuously monitored throughout the length of the fiber. Several vertical thermistor strings were also recording ground temperatures to a depth of 10 m in parallel to the fiber optic to verify the measurements collected from the fiber optic cable. GPS, Electronic Distance Measurement (EDM) Traditional and LiDAR (Light and Detection and Ranging) scanning were used to investigate the surface subsidence. The heaters were operating for approximately a three month period starting in August, 2016. During the heating process the soil temperatures at the heater element increased from 3.5 to 45 °C at a depth of 3 - 4 m. It took approximately 7 months for the temperature at the heater elements to recover to their initial temperature. The depth to the permafrost table was deepened by about 1 m during the heating process. By the end of the active heating, the surface had subsided approximately 8 cm in the heating section where permafrost was closest to the surface. This was conclusively confirmed with GPS, EDM, and LiDAR. An additional LiDAR survey was performed about seven months after the heaters were turned off (in May 2017). A total subsidence of approximately 20 cm was measured by the end of the passive heating process. This project successfully demonstrates that this is a viable approach for simulating both deep permafrost thaw and the resulting surface subsidence.

  3. A Holocene History of Permafrost Dynamics, Carbon Sequestration, and Hydrological Changes at Beretta Bog, Mackenzie River Basin

    Science.gov (United States)

    Von Ness, K.; Loisel, J.; Beilman, D. W.; Kaiser, K.

    2017-12-01

    The Mackenzie River Basin (MRB) is one of the world's largest permafrost peatland areas. This region contains dense soil carbon deposits and is home of the largest Canadian Arctic watershed. However, much remains to be known about the timing of permafrost initiation and the moisture changes that have affected soil development across this region throughout the Holocene. Peatland hydroclimatic conditions, which impact permafrost freezing and thawing as well as carbon sequestration rates, are relatively undocumented in peat-based paleoreconstructions. To provide further insight into the region's permafrost dynamics and the moisture changes associated with them, this study presents a permafrost initiation history and paleohydrological reconstruction of Beretta Bog, MRB that dates back to roughly 9000 cal BP. We explore the use of lichens as a bio-indicator of permafrost formation by quantifying the abundance of lichen-specific carbohydrates (mannose and galactose) in the peat profile. Testate amoebae, plant macrofossils, and carbon and oxygen isotopes (δ13C and δ18O) are also being analyzed at high resolution to reconstruct past changes in soil moisture and temperature. To our knowledge this study will constitute the first high-resolution paleohydrological reconstruction for this region. While carbohydrate analysis is underway, high C/N values from 6000 cal BP to present are temporarily used as an indicator for permafrost aggradation. Carbon accumulation rates of the core are highest prior to 6000 cal BP (during the Holocene Thermal Maximum) and relatively lower until around 1000 cal BP; we hypothesize this period of slow accumulation corresponds to permafrost aggradation. Preliminary results of our δ13C analysis corroborate testate assemblages as a proxy suitable for revealing moisture changes in permafrost peat. In the upper core, our analysis shows that more negative δ13C values, which reflect drier conditions, correlate to higher percentages of A. flavum and H

  4. Limited contribution of permafrost carbon to methane release from thawing peatlands

    Science.gov (United States)

    Cooper, Mark D. A.; Estop-Aragonés, Cristian; Fisher, James P.; Thierry, Aaron; Garnett, Mark H.; Charman, Dan J.; Murton, Julian B.; Phoenix, Gareth K.; Treharne, Rachael; Kokelj, Steve V.; Wolfe, Stephen A.; Lewkowicz, Antoni G.; Williams, Mathew; Hartley, Iain P.

    2017-07-01

    Models predict that thaw of permafrost soils at northern high latitudes will release tens of billions of tonnes of carbon (C) to the atmosphere by 2100 (refs ,,). The effect on the Earth’s climate depends strongly on the proportion of this C that is released as the more powerful greenhouse gas methane (CH4), rather than carbon dioxide (CO2) (refs ,); even if CH4 emissions represent just 2% of the C release, they would contribute approximately one-quarter of the climate forcing. In northern peatlands, thaw of ice-rich permafrost causes surface subsidence (thermokarst) and water-logging, exposing substantial stores (tens of kilograms of C per square meter, ref. ) of previously frozen organic matter to anaerobic conditions, and generating ideal conditions for permafrost-derived CH4 release. Here we show that, contrary to expectations, although substantial CH4 fluxes (>20 g CH4 m-2 yr-1) were recorded from thawing peatlands in northern Canada, only a small amount was derived from previously frozen C (changes in surface wetness and wetland area, rather than the anaerobic decomposition of previously frozen C, may determine the effect of permafrost thaw on CH4 emissions from northern peatlands.

  5. Transitory Ischemia as a form of white torture: a case description in Spain.

    Science.gov (United States)

    Pérez-Sales, Pau; Fernández-Liria, Alberto; Parras, Marina; Engst, Gina

    2010-01-01

    Transitory Ischemia is a form of torture that has been insufficiently described and studied in forensic and psychiatric studies of torture. It is usually left out of medical evaluation reports and not explored in detail under the Istanbul Protocol. Although ischemia, when experienced during brief periods of time, does not produce any detectable sequelae, prolonged periods of ischemia can be detected by either clinical examination or electromyography. The authors describe the use of brief periods of ischemia as a torture technique against a non-violent activist in Seville (Spain).

  6. Transitory cell attachments in the differentiating glomerular epithelium of the opossum metanephros.

    Science.gov (United States)

    Krause, W J; Cutts, J H

    1980-01-01

    Numerous transitory intercellular attachments are observed between the central, lateral surfaces of adjacent glomerular epithelial cells in the differentiating renal corpuscle. The junctions are characterized by an increased electron density of the adjacent cell membranes and cytoplasm. The intervening intercellular space may contain an amorphous material of moderate electron density. The distribution and position of such temporary cell attachments, together with their modification and subsequent loss during the differentiation of podocytes, suggest that they play an important role in the histogenesis of the glomerular epithelium.

  7. Permafrost degradation stimulates carbon loss from experimentally warmed tundra.

    Science.gov (United States)

    Natali, Susan M; Schuur, Edward A G; Webb, Elizabeth E; Pries, Caitlin E Hicks; Crummer, Kathryn G

    2014-03-01

    A large pool of organic carbon (C) has been accumulating in the Arctic for thousands of years because cold and waterlogged conditions have protected soil organic material from microbial decomposition. As the climate warms this vast and frozen C pool is at risk of being thawed, decomposed, and released to the atmosphere as greenhouse gasses. At the same time, some C losses may be offset by warming-mediated increases in plant productivity. Plant and microbial responses to warming ultimately determine net C exchange from ecosystems, but the timing and magnitude of these responses remain uncertain. Here we show that experimental warming and permafrost (ground that remains below 0 degrees C for two or more consecutive years) degradation led to a two-fold increase in net ecosystem C uptake during the growing season. However, warming also enhanced winter respiration, which entirely offset growing-season C gains. Winter C losses may be even higher in response to actual climate warming than to our experimental manipulations, and, in that scenario, could be expected to more than double overall net C losses from tundra to the atmosphere. Our results highlight the importance of winter processes in determining whether tundra acts as a C source or sink, and demonstrate the potential magnitude of C release from the permafrost zone that might be expected in a warmer climate.

  8. Metabolic activity of permafrost bacteria below the freezing point

    Science.gov (United States)

    Rivkina, E. M.; Friedmann, E. I.; McKay, C. P.; Gilichinsky, D. A.

    2000-01-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5 degrees C) to 20 days (-10 degrees C) to ca. 160 days (-20 degrees C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature.

  9. Anthropogenic structures in the geosystems (landscapes) of the permafrost zone

    International Nuclear Information System (INIS)

    Antonov-Druzhinin, V.P.

    1991-01-01

    Problems created by oil and gas field development in Arctic regions attract much attention in the discussion of the interaction of civil and industrial buildings and structures with permafrost. The investigations carried out must permit the evaluation of changes in the natural environment and single out the anthropogenic component of these changes, must ensure accident-free operation of oil and gas transport units, safety of people and environmental control in the mineral resource production regions of the Arctic. Taking the pipeline-environment system example, this report characterizes the spatial-temporal structure of the gas transport geotechnical system as a natural-anthropogenic, physico-geographical object. The natural sub-system of this object consists of several structures (referred to as areas and zones). These structures are characterized by different dynamics of regeneration processes of anthropogenic disturbances. It is found that the most negative ecological consequences during the development of the regions at the boundary of tundra and forest-tundra are associated with the disturbances of pre-tundra forests. The least perceptible ecological changes are typical for anthropogenic transformation of bog geo-systems. The anthropogenic structures, which are formed here, are characterized by a state most similar to the initial conditions and, often, by an increase of biomass in the landscapes. All these data are presented according to the author's investigations in the permafrost zone of Western Siberia

  10. Quality and Distribution of Frozen Organic Matter (Old, Deep, Fossil Carbon) in Siberian Permafrost

    Science.gov (United States)

    Schirrmeister, Lutz; Strauss, Jens; Wetterich, Sebastian; Grosse, Guido; Overduin, Pier Paul

    2013-04-01

    Permafrost deposits constitute a large organic carbon (OC) pool vulnerable to degradation and potential carbon release due to global warming. Permafrost sections along coastal and river bank exposures and subsea cores in northeastern Siberia were studied for organic matter (OM) characteristics and ice content. OM stored in Quaternary permafrost grew, accumulated, froze, partly decomposed, and refroze under different periglacial environments, reflected in specific biogeochemical and cryolithological features. For the studied individual strata (Saalian ice-rich deposits, Pre-Eemian floodplain, Eemian lake deposits, Early to Middle Weichselian fluvial deposits, Middle Weichselian Yedoma, Late Weichselian Yedoma , Taberites, Holocene cover, Holocene thermokarst, Holocene thermoerosional valley and submerged lagoon and fluvial deposits) OM accumulation, preservation, and distribution are strongly linked to a broad variety of paleoenvironmental factors and specific surface and subsurface conditions before inclusion of OM into the permafrost. OM in permafrost includes twigs, leaves, peat, grass roots, plant detritus, and particulate and dissolved OM. The vertical distribution of total OC (TOC) in exposures varies from 0.1 wt % of the dry sediment in fluvial deposits to 45 wt % in Holocene peats. High TOC, high C/N, and low d13C reflect less decomposed OM accumulated under wet, anaerobic soil conditions characteristic of interglacial and interstadial periods. Glacial and stadial periods are characterized by less variable, low TOC, low C/N, and high d13C values indicating stable environments with reduced bioproductivity and stronger OM decomposition under dryer, aerobic soil conditions. Based on TOC data and updated information on bulk densities, we estimate average OC inventories for different stratigraphic units in northeastern Siberia, ranging from 7 kg C/m³ for Early Weichselian fluvial deposits, to 33 kg C/m³ for Middle Weichselian Yedoma deposits, to 75 kg C/m³ for

  11. Cryogenic and non-cryogenic pool calcites indicating permafrost and non-permafrost periods: a case study from the Herbstlabyrinth-Advent Cave system (Germany

    Directory of Open Access Journals (Sweden)

    D. K. Richter

    2010-11-01

    Full Text Available Weichselian cryogenic calcites collected in what is referred to as the Rätselhalle of the Herbstlabyrinth-Advent Cave system are structurally classified as rhombohedral crystals and spherulitic aggregates. The carbon and oxygen isotopic composition of these precipitates (δ13C = +0.6 to −7.3‰ δ18O = −6.9 to −18.0‰ corresponds to those of known slowly precipitated cryogenic cave calcites under conditions of isotopic equilibrium between water and ice of Central European caves. The carbon and oxygen isotopic composition varies between different caves which is attributed to the effects of cave air ventilation before the freezing started.

    By petrographic and geochemical comparisons of Weichselian cryogenic calcite with recent to sub-recent precipitates as well as Weichselian non-cryogenic calcites of the same locality, a model for the precipitation of these calcites is proposed. While the recent and sub-recent pool-calcites isotopically match the composition of interglacial speleothems (stalagmites, etc., isotope ratios of Weichselian non-cryogenic pool-calcites reflect cooler conditions. Weichselian cryogenic calcites show a trend towards low δ18O values with higher carbon isotope ratios reflecting slow freezing of the precipitating solution. In essence, the isotope geochemistry of the Weichselian calcites reflects the climate history changing from overall initial permafrost conditions to permafrost-free and subsequently to renewed permafrost conditions. Judging from the data compiled here, the last permafrost stage in the Rätselhalle is followed by a warm period (interstadial and/or Holocene. During this warmer period, the cave ice melted and cryogenic and non-cryogenic Weichselian calcite precipitates were deposited on the cave ground or on fallen blocks, respectively.

  12. Permafrost in the Himalayas: specific characteristics, evolution vs. climate change and impacts on potential natural hazards

    Science.gov (United States)

    Fort, Monique

    2015-04-01

    mass-wasting and debris-flow events and may directly threat the infrastructures recently built to unlock these remote areas. Secondly, acceleration of permafrost degradation might also affect the steepest rock walls (as in Khumbu, Manang and Mustang Himals) and cause rock avalanches that could impact nearby settlements, as suggested by relicts of past events. Lastly, ground ice is a hidden source of water in areas without permanent glacial ice. In a context of global warming this non-renewable resource would be depleted and no longer available for the population living in these areas, all the more as growing tourism activities are increasing the demand for water consumption that may conflicts with irrigated agricultural uses down valley. More in-situ observations and long-term monitoring studies should certainly be useful to understand climate trends hence permafrost evolution and their consequences in order to help mountain populations of the cold, arid Himalayas to adjust to progressive changes in their environmental conditions and resources.

  13. Land Resources of Russia -- Maps of Permafrost and Ground Ice, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes maps of permafrost extent, permafrost temperature, the permafrost boundary, and ground ice thickness for all of Russia. The maps are ESRI...

  14. Permafrost distribution map of San Juan Dry Andes (Argentina) based on rock glacier sites

    Science.gov (United States)

    Esper Angillieri, María Yanina

    2017-01-01

    Rock glaciers are frozen water reservoirs in mountainous areas. Water resources are important for the local populations and economies. The presence of rock glaciers is commonly used as a direct indicator of mountain permafrost conditions. Over 500 active rock glaciers have been identified, showing that elevations between 3500 and 4500 m asl., a south-facing or east-facing aspect, areas with relatively low solar radiation and low mean annual air temperature (-4 to 0 °C) favour the existence of rock glaciers in this region. The permafrost probability model, for Dry Andes of San Juan Province between latitudes 28º30‧S and 32°30‧S, have been analyzed by logistic regression models based on the active rock glaciers occurrence in relation to some topoclimatic variables such as altitude, aspect, mean annual temperature, mean annual precipitation and solar radiation, using optical remote sensing techniques in a GIS environment. The predictive performances of the model have been estimated by known rock glaciers locations and by the area under the receiver operating characteristic curve (AUROC). This regional permafrost map can be applied by the Argentinean Government for their recent initiatives which include creating inventories, monitoring and studying ice masses along the Argentinean Andes. Further, this generated map provides valuable input data for permafrost scenarios and contributes to a better understanding of our geosystem.

  15. Simulation of pollutant transport in mobile water-flow channels in permafrost environment

    Directory of Open Access Journals (Sweden)

    E. I. Debolskaya

    2013-01-01

    Full Text Available A common problem for the Arctic region is pollution by persistent organic compounds and other substances that have accumulated over the years in these areas. With temperature increasing, these substances can get out of the snow, ice, permafrost in the human environment. With climate warming and permafrost degradation the risk of toxic substances from the burial sites of chemical and radioactive waste increases. The work is devoted to research the pollution propagation in the rivers flowing in the permafrost taking into account the possible deformations of the channels caused by the melting of the permafrost with increasing temperature of the river flow water. We also consider the distribution of pollutants released during erosion of the coastal slopes, caused thermal erosion. Numerical experiments confirmed the quantitative assessment obtained from the field observations of the erosion rate increases with increasing temperature. Study the impact of thermal and mechanical erosion of the distribution of impurities led to the conclusion that as a result of the formation of taliks uniform flow conditions are violated, resulting in a non-stationary distribution of impurities. The increase in the volume of the test section of the river due to the appearance of cavities in the coastal slope leads to an increase in impurity concentration. Analysis of the results of modeling the spread of contamination during thawing sources in the frozen shores, demonstrated the relationship in the process of distribution of impurities from the position of the source and allowed to give a preliminary quantitative assessment.

  16. Semiautomatic mapping of permafrost in the Yukon Flats, Alaska

    Science.gov (United States)

    Gulbrandsen, Mats Lundh; Minsley, Burke J.; Ball, Lyndsay B.; Hansen, Thomas Mejer

    2016-01-01

    Thawing of permafrost due to global warming can have major impacts on hydrogeological processes, climate feedback, arctic ecology, and local environments. To understand these effects and processes, it is crucial to know the distribution of permafrost. In this study we exploit the fact that airborne electromagnetic (AEM) data are sensitive to the distribution of permafrost and demonstrate how the distribution of permafrost in the Yukon Flats, Alaska, is mapped in an efficient (semiautomatic) way, using a combination of supervised and unsupervised (machine) learning algorithms, i.e., Smart Interpretation and K-means clustering. Clustering is used to sort unfrozen and frozen regions, and Smart Interpretation is used to predict the depth of permafrost based on expert interpretations. This workflow allows, for the first time, a quantitative and objective approach to efficiently map permafrost based on large amounts of AEM data.

  17. Simulation of the fault transitory of the feedwater controller in a Boiling water reactor with the Ramona-3B code

    International Nuclear Information System (INIS)

    Hernandez M, J.L.; Ortiz V, J.

    2005-01-01

    The obtained results when carrying out the simulation of the fault transitory of the feedwater controller (FCAA) with the Ramona-3B code, happened in the Unit 2 of the Laguna Verde power plant (CNLV), in September of the year 2000 are presented. The transitory originates as consequence of the controller's fault of speed of a turbo pump of feedwater. The work includes a short description of the event, the suppositions considered for the simulation and the obtained results. Also, a discussion of the impact of the transitory event is presented on aspects of reactor safety. Although the carried out simulation is limited by the capacities of the code and for the lack of available information, it was found that even in a conservative situation, the power was incremented only in 12% above the nominal value, while that the thermal limit determined by the minimum reason of the critical power, MCPR, always stayed above the limit values of operation and safety. (Author)

  18. Utilizing Vegetation Indices as a Proxy to Characterize the Stability of a Railway Embankment in a Permafrost Region

    Directory of Open Access Journals (Sweden)

    Priscilla Addison

    2016-11-01

    Full Text Available Degrading permafrost conditions around the world are posing stability issues for infrastructure constructed on them. Railway lines have exceptionally low tolerances for differential settlements associated with permafrost degradation due to the potential for train derailments. Railway owners with tracks in permafrost regions therefore make it a priority to identify potential settlement locations so that proper maintenance or embankment stabilization measures can be applied to ensure smooth and safe operations. The extensive discontinuous permafrost zone along the Hudson Bay Railway (HBR in Northern Manitoba, Canada, has been experiencing accelerated deterioration, resulting in differential settlements that necessitate continuous annual maintenance to avoid slow orders and operational interruptions. This paper seeks to characterize the different permafrost degradation susceptibilities present at the study site. Track geometry exceptions were compared against remotely sensed vegetation indices to establish a relationship between track quality and vegetation density. This relationship was used as a proxy for subsurface condition verified by electrical resistivity tomography. The established relationship was then used to develop a three-level degradation susceptibility chart to indicate low, moderate and high susceptibility regions. The defined susceptibility regions can be used to better allocate the limited maintenance resources and also help inform potentially long-term stabilization measures for the severely affected sections.

  19. Data-driven mapping of the potential mountain permafrost distribution.

    Science.gov (United States)

    Deluigi, Nicola; Lambiel, Christophe; Kanevski, Mikhail

    2017-07-15

    Existing mountain permafrost distribution models generally offer a good overview of the potential extent of this phenomenon at a regional scale. They are however not always able to reproduce the high spatial discontinuity of permafrost at the micro-scale (scale of a specific landform; ten to several hundreds of meters). To overcome this lack, we tested an alternative modelling approach using three classification algorithms belonging to statistics and machine learning: Logistic regression, Support Vector Machines and Random forests. These supervised learning techniques infer a classification function from labelled training data (pixels of permafrost absence and presence) with the aim of predicting the permafrost occurrence where it is unknown. The research was carried out in a 588km 2 area of the Western Swiss Alps. Permafrost evidences were mapped from ortho-image interpretation (rock glacier inventorying) and field data (mainly geoelectrical and thermal data). The relationship between selected permafrost evidences and permafrost controlling factors was computed with the mentioned techniques. Classification performances, assessed with AUROC, range between 0.81 for Logistic regression, 0.85 with Support Vector Machines and 0.88 with Random forests. The adopted machine learning algorithms have demonstrated to be efficient for permafrost distribution modelling thanks to consistent results compared to the field reality. The high resolution of the input dataset (10m) allows elaborating maps at the micro-scale with a modelled permafrost spatial distribution less optimistic than classic spatial models. Moreover, the probability output of adopted algorithms offers a more precise overview of the potential distribution of mountain permafrost than proposing simple indexes of the permafrost favorability. These encouraging results also open the way to new possibilities of permafrost data analysis and mapping. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A new map of permafrost distribution on the Tibetan Plateau

    Science.gov (United States)

    Zou, Defu; Zhao, Lin; Sheng, Yu; Chen, Ji; Hu, Guojie; Wu, Tonghua; Wu, Jichun; Xie, Changwei; Wu, Xiaodong; Pang, Qiangqiang; Wang, Wu; Du, Erji; Li, Wangping; Liu, Guangyue; Li, Jing; Qin, Yanhui; Qiao, Yongping; Wang, Zhiwei; Shi, Jianzong; Cheng, Guodong

    2017-11-01

    The Tibetan Plateau (TP) has the largest areas of permafrost terrain in the mid- and low-latitude regions of the world. Some permafrost distribution maps have been compiled but, due to limited data sources, ambiguous criteria, inadequate validation, and deficiency of high-quality spatial data sets, there is high uncertainty in the mapping of the permafrost distribution on the TP. We generated a new permafrost map based on freezing and thawing indices from modified Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperatures (LSTs) and validated this map using various ground-based data sets. The soil thermal properties of five soil types across the TP were estimated according to an empirical equation and soil properties (moisture content and bulk density). The temperature at the top of permafrost (TTOP) model was applied to simulate the permafrost distribution. Permafrost, seasonally frozen ground, and unfrozen ground covered areas of 1.06 × 106 km2 (0.97-1.15 × 106 km2, 90 % confidence interval) (40 %), 1.46 × 106 (56 %), and 0.03 × 106 km2 (1 %), respectively, excluding glaciers and lakes. Ground-based observations of the permafrost distribution across the five investigated regions (IRs, located in the transition zones of the permafrost and seasonally frozen ground) and three highway transects (across the entire permafrost regions from north to south) were used to validate the model. Validation results showed that the kappa coefficient varied from 0.38 to 0.78 with a mean of 0.57 for the five IRs and 0.62 to 0.74 with a mean of 0.68 within the three transects. Compared with earlier studies, the TTOP modelling results show greater accuracy. The results provide more detailed information on the permafrost distribution and basic data for use in future research on the Tibetan Plateau permafrost.

  1. Effects of permafrost degradation on alpine grassland in a semi-arid basin on the Qinghai–Tibetan Plateau

    International Nuclear Information System (INIS)

    Yi Shuhua; Zhou Zhaoye; Ren Shilong; Xu Ming; Qin Yu; Chen Shengyun; Ye Baisheng

    2011-01-01

    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.

  2. Data Integration Tool: Permafrost Data Debugging

    Science.gov (United States)

    Wilcox, H.; Schaefer, K. M.; Jafarov, E. E.; Pulsifer, P. L.; Strawhacker, C.; Yarmey, L.; Basak, R.

    2017-12-01

    We developed a Data Integration Tool (DIT) to significantly speed up the time of manual processing needed to translate inconsistent, scattered historical permafrost data into files ready to ingest directly into the Global Terrestrial Network-Permafrost (GTN-P). The United States National Science Foundation funded this project through the National Snow and Ice Data Center (NSIDC) with the GTN-P to improve permafrost data access and discovery. We leverage this data to support science research and policy decisions. DIT is a workflow manager that divides data preparation and analysis into a series of steps or operations called widgets (https://github.com/PermaData/DIT). Each widget does a specific operation, such as read, multiply by a constant, sort, plot, and write data. DIT allows the user to select and order the widgets as desired to meet their specific needs, incrementally interact with and evolve the widget workflows, and save those workflows for reproducibility. Taking ideas from visual programming found in the art and design domain, debugging and iterative design principles from software engineering, and the scientific data processing and analysis power of Fortran and Python it was written for interactive, iterative data manipulation, quality control, processing, and analysis of inconsistent data in an easily installable application. DIT was used to completely translate one dataset (133 sites) that was successfully added to GTN-P, nearly translate three datasets (270 sites), and is scheduled to translate 10 more datasets ( 1000 sites) from the legacy inactive site data holdings of the Frozen Ground Data Center (FGDC). Iterative development has provided the permafrost and wider scientific community with an extendable tool designed specifically for the iterative process of translating unruly data.

  3. Microbial Metabolism in Permafrost and Ice

    Science.gov (United States)

    Price, P. B.; Bramall, N.; Bay, R. C.

    2003-12-01

    Metabolic rates of microbial communities at low temperature have not been systematically studied, despite discoveries of microbes that survive with very little nutrient in ice, permafrost, and deep open-ocean sites, and despite interest in possible life on Mars and Europa. We investigated the temperature-dependence of growth rates kg, maintenance rates km, and survival rates ks, using existing data on kg(T) for permafrost bacteria, on km(T) using radiotracers, and on ks(T) using geochemical methods. Data were collected for temperatures from 28° C to -40° C. The rates for the three modes are consistent with a single activation energy U ≈ 100-110 kJ/mol, and they scale as kg(T):km(T):ks(T) ≈ 107:104:1. The rate ks(T) for survival of a dormant microbial community is found to be roughly that required solely for repairing molecular damage due to amino acid racemization + DNA depurination. We conclude that for living microbes the rate of molecular repair equals the rate of molecular damage. There is no indication of a threshold temperature for metabolism, at least down to -40° C. To assay microbial life in the coldest terrestrial environments (down to -55° C) and in future to search for present or past life on Mars, we have designed a miniaturized biospectral logger that will fit into a 4-cm borehole in ice, permafrost and rock. The logger will use side-directed laser beams at wavelengths 224 and 370 nm to detect autofluorescence of biomolecules and discriminate against mineral autofluorescence. Six channels will map fluorescence spectra and a seventh channel will measure light scattered from dust (in ice) or rock (in permafrost). Fluorescent biomolecules of interest include tryptophan, tyrosine, NADH, FAD, F420, chlorophyll, bacteriorhodopsin, porphyrins, pyoverdin, PAHs, humic acid, and fulvic acid. The logger will be able to detect microbial concentrations as low as 1 cell cm-3 in clean ice.

  4. Borehole temperatures from mountain permafrost monitoring, Mongolia, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Location and description of some geocryological boreholes in Mongolia. Data include latitude, longitude, location, depth of permafrost top and bottom, and mean...

  5. Borehole permafrost data, Kumtor and Taragai Valleys, Tienshan, Kazakhstan, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset includes observations of the permafrost temperatures in the Inner Tien Shan were started in 1986 by Kazakhstan Alpine Permafrost Laboratory....

  6. Stochastic analysis of uncertain thermal characteristic of foundation soils surrounding the crude oil pipeline in permafrost regions

    International Nuclear Information System (INIS)

    Wang, Tao; Zhou, Guoqing; Wang, Jianzhou; Zhao, Xiaodong

    2016-01-01

    Highlights: • The influence of stochastic properties and conditions on permafrost foundation was investigated. • A stochastic analysis for the uncertain thermal characteristic of crude oil pipe is presented. • The mean temperature and standard deviation of foundation soils are obtained and analyzed. • Average standard deviation and maximum standard deviation of foundation soils increase with time. - Abstract: For foundation soils surrounding the crude oil pipeline in permafrost regions, the soil properties and the upper boundary conditions are stochastic because of complex geological processes and changeable atmospheric environment. The conventional finite element analysis of thermal characteristics for crude oil pipeline is always deterministic, rather than taking stochastic parameters and conditions into account. This study investigated the stochastic influence of an underground crude oil pipeline on the thermal stability of the permafrost foundation on the basis of a stochastic analysis model and the stochastic finite element method. A stochastic finite element program is compiled by Matrix Laboratory (MATLAB) software, and the random temperature fields of foundation soils surrounding a crude oil pipeline in a permafrost region are obtained and analyzed by Neumann stochastic finite element method (NSFEM). The results provide a new way to predict the thermal effects of the crude oil pipeline in permafrost regions, and it shows that the standard deviations in temperature increase with time when considering the stochastic effect of soil properties and boundary conditions, which imply that the results of conventional deterministic analysis may be far from the true value, even if in different seasons. It can improve our understanding of the random temperature field of foundation soils surrounding the crude oil pipeline and provide a theoretical basis for actual engineering design in permafrost regions.

  7. Ice sheet - permafrost interactions inferred from the sedimentary record of Weichselian glaciation in Poland

    Science.gov (United States)

    Szuman, I.; Ewertowski, M.; Kasprzak, L.; Piotrowski, J. A.

    2012-04-01

    low strength so that deformation was focussed in fine sand whereas the fully frozen gavels remained relatively stable. Subglacial permafrost hampered meltwater drainage in favor of water storage at the ice/bed interface which could have led to hydraulic uplifting of ice mass. The subglacial permafrost was strongly influenced by local hydrothermal conditions. Due to the high geothermal heat flux in this part of Poland of up to 100 mW/m2 it was most likely thin and discontinuous.

  8. Climate hazards caused by thawing permafrost? Background information of the Federal Environmental Agency; Klimagefahr durch tauenden Permafrost? UBA-Hintergrundpapier

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-08-15

    The thawing of permafrost regions is supposed to increase climatic change processes due to the released methane. During the last decades the temperature of permafrost soils has increased by several tenths of degree up to 2 deg C. It is supposed that 10 to 20% of the permafrost regions will thaw during the next 100 years. The southern boundary of the permafrost region will move several hundred kilometers toward the north. Besides the increased risk for the climate system there will also be disadvantageous consequences for the ecosystems. Negative economic consequences are already observed and will be enhanced in the futures with significant cost for the public.

  9. Landsat-based trend analysis of lake dynamics across northern permafrost regions

    Science.gov (United States)

    Nitze, Ingmar; Grosse, Guido; Jones, Benjamin M.; Arp, Christopher D.; Ulrich, Mathias; Federov, Alexander; Veremeeva, Alexandra

    2017-01-01

    Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here we present, a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM,ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e. upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.

  10. Comparison of algorithms and parameterisations for infiltration into organic-covered permafrost soils

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2010-05-01

    Full Text Available Infiltration into frozen and unfrozen soils is critical in hydrology, controlling active layer soil water dynamics and influencing runoff. Few Land Surface Models (LSMs and Hydrological Models (HMs have been developed, adapted or tested for frozen conditions and permafrost soils. Considering the vast geographical area influenced by freeze/thaw processes and permafrost, and the rapid environmental change observed worldwide in these regions, a need exists to improve models to better represent their hydrology.

    In this study, various infiltration algorithms and parameterisation methods, which are commonly employed in current LSMs and HMs were tested against detailed measurements at three sites in Canada's discontinuous permafrost region with organic soil depths ranging from 0.02 to 3 m. Field data from two consecutive years were used to calibrate and evaluate the infiltration algorithms and parameterisations. Important conclusions include: (1 the single most important factor that controls the infiltration at permafrost sites is ground thaw depth, (2 differences among the simulated infiltration by different algorithms and parameterisations were only found when the ground was frozen or during the initial fast thawing stages, but not after ground thaw reaches a critical depth of 15 to 30 cm, (3 despite similarities in simulated total infiltration after ground thaw reaches the critical depth, the choice of algorithm influenced the distribution of water among the soil layers, and (4 the ice impedance factor for hydraulic conductivity, which is commonly used in LSMs and HMs, may not be necessary once the water potential driven frozen soil parameterisation is employed. Results from this work provide guidelines that can be directly implemented in LSMs and HMs to improve their application in organic covered permafrost soils.

  11. Greenhouse gas balance over thaw-freeze cycles in discontinuous zone permafrost

    Science.gov (United States)

    Wilson, R. M.; Fitzhugh, L.; Whiting, G. J.; Frolking, S.; Harrison, M. D.; Dimova, N.; Burnett, W. C.; Chanton, J. P.

    2017-02-01

    Peat in the discontinuous permafrost zone contains a globally significant reservoir of carbon that has undergone multiple permafrost-thaw cycles since the end of the mid-Holocene ( 3700 years before present). Periods of thaw increase C decomposition rates which leads to the release of CO2 and CH4 to the atmosphere creating potential climate feedback. To determine the magnitude and direction of such feedback, we measured CO2 and CH4 emissions and modeled C accumulation rates and radiative fluxes from measurements of two radioactive tracers with differing lifetimes to describe the C balance of the peatland over multiple permafrost-thaw cycles since the initiation of permafrost at the site. At thaw features, the balance between increased primary production and higher CH4 emission stimulated by warmer temperatures and wetter conditions favors C sequestration and enhanced peat accumulation. Flux measurements suggest that frozen plateaus may intermittently (order of years to decades) act as CO2 sources depending on temperature and net ecosystem respiration rates, but modeling results suggest that—despite brief periods of net C loss to the atmosphere at the initiation of thaw—integrated over millennia, these sites have acted as net C sinks via peat accumulation. In greenhouse gas terms, the transition from frozen permafrost to thawed wetland is accompanied by increasing CO2 uptake that is partially offset by increasing CH4 emissions. In the short-term (decadal time scale) the net effect of this transition is likely enhanced warming via increased radiative C emissions, while in the long-term (centuries) net C deposition provides a negative feedback to climate warming.

  12. Permafrost Changes along the Alaska Highway Corridor, Southern Yukon, from Ground Temperature Measurements and DC Electrical Resistivity Tomography

    Science.gov (United States)

    Duguay, M. A.; Lewkowicz, A. G.; Smith, S.

    2011-12-01

    A natural gas pipeline running across permafrost terrain from Prudhoe Bay, Alaska, through Canada to US markets was first proposed more than 30 years ago. In the intervening period, mean annual air temperatures in the region have risen by 0.5-1.0°C and it is probable that the ground has also warmed. Renewed interest in the pipeline has meant that information on permafrost and geotechnical conditions within the Alaska Highway Corridor of the southern Yukon must be updated for engineering design and the assessment of environmental impacts. To accomplish this goal, results from 1977-1981 drilling and ground temperature monitoring programs within the proposed pipeline corridor were used in combination with air photo analysis to select sites potentially sensitive to climate change. The sites are distributed across the extensive and sporadic discontinuous permafrost zones over a distance of 475 km between Beaver Creek and Whitehorse. To date, 11 targeted boreholes with permafrost have been found and cased to permit renewed ground temperature monitoring. By the end of summer 2011, it is expected that another 7 will have been instrumented. Measurable temperature increases relative to the 1970s are expected, except where values were previously just below 0°C. In the latter case, if the sites are still in permafrost, latent heat effects may have substantially moderated the temperature increase. Electrical resistivity tomography surveys are also being conducted to characterize the local permafrost distribution and geotechnical conditions. These 2D resistivity profiles will be used with the ground temperatures to examine current conditions and response to climate change and vegetation disturbance.

  13. An Empirical Study on Transit-Oriented Low-Carbon Urban Land Use Planning

    DEFF Research Database (Denmark)

    Dou, Yi; Luo, Xiao; Dong, Liang

    2016-01-01

    Low-carbon urban development is a hot spot of global concerns for fighting against climate change for China, transportation sector has a significant contribution to urban CO2 emissions, while the emissions are still increasing. Transit-Oriented Development (TOD) strategies provide a novel approach...... for urban planners to facilitate the urban carbon mitigation from transportation sector in long-term. While TOD strategies are emerging cases, they are merely qualitatively discussed in China, lacking practical indicators and quantitative verification for supporting the real urban plan...... population and transportation accessibility with Geographic Weighted Regression model. Results highlight that TOD can effectively improve the transportation network with higher accessibility and lower urban carbon emissions. The outcomes of this study provide critical insights to the recent practice...

  14. Notions and methodologies for uncertainty analysis in simulations of transitory events of a nuclear central

    International Nuclear Information System (INIS)

    Alva N, J.; Ortiz V, J.; Amador G, R.; Delfin L, A.

    2007-01-01

    The present work has as objective to gather the basic notions related with the uncertainty analysis and some of the methodologies to be applied in the studies of transitory events analysis of a nuclear power station, in particular of those thermal hydraulics phenomena. The concepts and methodologies mentioned in this work are the result of an exhaustive bibliographical investigation of the topic in the nuclear area. The methodologies of uncertainties analysis have been developed by diverse institutions and they are broadly used at world level for their application in the results of the computer codes of the class of better estimation in the thermal hydraulics analysis and safety of plants and nuclear reactors. The main sources of uncertainty, types of uncertainty and aspects related with the models of better estimation and better estimation method are also presented. (Author)

  15. Transitory provisions on public gas distribution in the light of the Marzano law

    International Nuclear Information System (INIS)

    Vedaschi, Arianna

    2005-01-01

    The article begins by describing community law on public gas distribution service, then it examines legislative decree 164/2000( also called Letta Decree), which implements directive no. 98/30/CE. This directive reforms the gas sector and in particular it reforms the way gas is distributed. Art. 14 of the Letta Decree states that the distribution of natural gas shall be a public service, contractors shall be selected through a public tender and contracts shall be stipulate for a maximum of 12 years. Thus it is evident that the new model is radically different from the previous one. Before, the service was provided by the local authorities (either directly or through a long-term lease); now the new model aims at liberalizing the market by out sourcing gas distribution. Out sourcing is carried out through a public tender and for short periods of time. In order to allow a gradual transition from the old model to the new one, the Letta Decree provides for a transitory period articulated in various phases. This has the aim of guaranteeing a balance between the interest of local authorities, on one hand and the firms that distributed gas before the reform came into effect, on the other. The first part of the article focuses on interpretative problems that arose after law no. 239/2004 (so called Marzano law) was passed. In the second half it compares the different judicial interpretations concerning: a) duration of the transitory period; b) possibility of increasing duration as provided for by art. 15, par.7 of legislative decree 164/2000; c) efficacy of the abrogation of art. 15, par.8 of legislative decree 164/2000 and finally d) whether advanced redemption of the gas distribution service is still possible. With regards to the transitory period, the article compares judgement no. 111/2005 by the Administrative Tribunal of Lombardia, with judgement no. 6187/2005 delivered by the Sixth Section of the State Council. It then argues that the prohibition of concentration has

  16. Reducing uncertainty in methane emission estimates from permafrost peatlands

    Science.gov (United States)

    Christensen, Torben R.

    2016-04-01

    Reducing uncertainty in methane emission estimates from permafrost peatlands Torben R. Christensen1,2 and coworkers 1) Department of Physical Geography and Ecosystem Science, Lund University, Sweden 2) Arctic Research Centre, Aarhus University, Denmark Depending on factors including temperature, snow duration and soil moisture conditions, emissions of the greenhouse gas methane from permafrost peatlands can vary by factors of 2-4 between years. This variability is clear in atmospheric measurements of the gas, but a lack of ground-based data is making it hard to locate the methane sources responsible. Methane monitoring in the Arctic is expensive, requiring sophisticated analysis equipment such as power requiring laser spectrometer analysis made in remote places. This also puts demands on the logistics where infrastructures and field stations that offer line-power in the field are in high demand but very rarely found. Research projects therefore typically focus on one site, and run for a year or two. Longer term monitoring programs, which document climate, hydrology, phenology and population dynamics of birds and mammals, rarely include carbon fluxes since it is technically challenging to measure. One that does is the Greenland Ecosystem Monitoring program that started at the Zackenberg research station, which has recorded substantial methane flux variations for almost a decade in North-east Greenland. Such multi-year studies show that, while there is some connection between the amounts of methane released from one year to the next, accurate forecasting is difficult. They also highlight the importance of extending monitoring beyond the growing period into the frozen season, both in spring and autumn. A spatially distributed network of long-term monitoring stations in the Arctic, with consistency between measurements, is badly needed to improve this situation. Productive methane 'hot spots', many sporadic, have also been identified in recent studies. By ventilating

  17. Is the ancient permafrost bacteria able to keep DNA stable?

    Indian Academy of Sciences (India)

    Navya

    According to the preliminary DNA analysis, bacterial cells collected from the relict permafrost appeared to be Bacillus sp. strains, which are close to modern bacteria at a molecular level. Therefore, a number of question raises. For example, are isolated bacteria as old as the permafrost itself or could contamination with more ...

  18. Resilience and vulnerability of permafrost to climate change

    Science.gov (United States)

    M.Torre Jorgenson; Vladimir Romanovsky; Jennifer Harden; Yuri Shur; Jonathan O' Donnell; Edward A.G. Schuur; Mikhail Kanevskiy; Sergei. Marchenko

    2010-01-01

    The resilience and vulnerability of permafrost to climate change depends on complex interactions among topography, water, soil, vegetation, and snow, which allow permafrost to persist at mean annual air temperatures (MAATs) as high as +2 °C and degrade at MAATs as low as -20°C. To assess these interactions, we compiled existing data and tested effects of varying...

  19. Contribution of permafrost soils to the global carbon budget

    International Nuclear Information System (INIS)

    Schaphoff, Sibyll; Heyder, Ursula; Ostberg, Sebastian; Gerten, Dieter; Heinke, Jens; Lucht, Wolfgang

    2013-01-01

    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. (letter)

  20. Optimized transitory ectopic expression of promastigote surface antigen protein in Nicotiana benthamiana, a potential anti-leishmaniasis vaccine candidate.

    Science.gov (United States)

    Lacombe, Séverine; Bangratz, Martine; Brizard, Jean-Paul; Petitdidier, Elodie; Pagniez, Julie; Sérémé, Drissa; Lemesre, Jean-Loup; Brugidou, Christophe

    2018-01-01

    In recent years, plants have been shown to be an efficient alternative expression system for high-value pharmaceuticals such as vaccines. However, constitutive expression of recombinant protein remains uncertain on their level of production and biological activity. To overcome these problems, transitory expression systems have been developed. Here, a series of experiments were performed to determine the most effective conditions to enhance vaccine antigen transient accumulation in Nicotiana benthamiana leaves using the promastigote surface antigen (PSA) from the parasitic protozoan Leishmania infantum. This protein has been previously identified as the major antigen of a licensed canine anti-leishmaniasis vaccine. The classical prokaryote Escherichia coli biosystem failed in accumulating PSA. Consequently, the standard plant system based on N. benthamiana has been optimized for the production of putatively active PSA. First, the RNA silencing defense mechanism set up by the plant against PSA ectopic expression was abolished by using three viral suppressors acting at different steps of the RNA silencing pathway. Then, we demonstrated that the signal peptide at the N-terminal side of the PSA is required for its accumulation. The PSA ER signaling and retention with the PSA signal peptide and the KDEL motif, respectively were optimized to significantly increase its accumulation. Finally, we demonstrate that the production of recombinant PSA in N. benthamiana leaves allows the conservation of its immunogenic property. These approaches demonstrate that based on these optimizations, plant based systems can be used to effectively produce the biological active PSA protein. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Permafrost: An International Approach to 21th Century Challenges

    Science.gov (United States)

    Brown, J.

    2003-12-01

    Whereas glaciers are easily discernible to the human eye and satellites, permafrost terrains and their physical components are not easily detected from the surface without supplemental knowledge and measurements. In the Northern Hemisphere, approximately 17 million km2 of exposed land contains some extent of permafrost or ground that remains frozen for more than two years. The vast majority, or 11 million km2, of permafrost terrain has temperatures of 5° C or below, with perennially frozen ground underlying essentially all ground surfaces to considerable depths. Permafrost in the remaining regions, including mid-latitude mountains, is both warmer and is spatially variable (discontinuous). As climate warms the uppermost permafrost is subjected to increase thaw with resulting ground subsidence, accelerated erosion, and related biogeochemical modifications. The challenging questions to geocryologists, modelers and the public relate to the rate of change and the spatial variability of the projected thaw, particularly in the warmer zones where actual areal and subareal distribution of permafrost is poorly known. An international network of active layer measurements and borehole sites now exists under the Global Climate Observing System (GCOS), but requires additional sites for representative coverage. This Global Terrestrial Network for Permafrost (GTN-P) is coordinated by the 24-member, International Permafrost Association. At the Eighth International Conference on Permafrost (ICOP) in Zurich in July 2003, the IPA Council agreed on the scope of new activities for the next five years, many of which will be undertaken in cooperation with other international organizations (e.g. WCRP/CliC; ICSI, IASC, SCAR, IGU, IUGS). Examples of the activities of the IPA Working Groups are: 1. Antarctic Permafrost and Periglacial Environments (active layer processes, maps, database). 2. Coastal and Offshore Permafrost (sediment and organic transfers, subsea permafrost dynamics). 3

  2. Numerical simulations of permafrost dynamics in the source area of the Yellow River, central-eastern Qinghai-Tibet Plateau

    Science.gov (United States)

    Luo, D.; Marchenko, S. S.; Jin, H.; Romanovsky, V. E.

    2017-12-01

    Elevational permafrost on the Qinghai-Tibet Plateau (QTP) are particularly warm with more than half boreholes owning ground temperatures within -1 and 0 °C, therefore presumably sensitive to climate changes and anthropogenic activities. In the context of more serious climatic warming on the QTP than the global average, deterioration to ecology and damages to engineering projects in permafrost region had been frequently reported. To forecast further degradation of permafrost in the coming decades or centuries, a number of empirical or physical models have been implemented to study it. However, few attentions had been paid to variations of permafrost for the past century. In this study, we utilized the Geophysical Institute Permafrost (GIPL) model to simulate permafrost variations from 1901 to 2015 in the source area of the Yellow River, central-eastern QTP. Monthly air temperatures and precipitation from the CRU TS 4.0 datasets in 1901-2015 were employed as the input upper boundary conditions. Thermo-physical properties and moisture content of subsurface soils collected from the fieldwork and in situ measurements of ground temperatures were employed as initial conditions. An empirical estimated geothermal heat flux for each grid point was applied for the lower boundary conditions. Monthly air temperatures of 1901 were repeated for 50 times to drive the model to obtain thermal equilibrium, and then the measured ground temperatures were utilized to calibrate the soil properties. Results showed that, the mean annual air temperature (MAAT) did not dramatically change by a rate of consistently continuous increasing, but by rates of 0.27 °C·(10a)-1 in 1901-1944, -0.19 °C·(10a)-1 in 1945-1983, and 0.18°C·(10a)-1 in 1984-2015, while the overall trend was 0.02 °C·(10a)-1. During the past centennial periods, variations of permafrost temperatures at different depths resembled the fluctuation of air temperature with an attenuation effect downwards. During the period of

  3. Permafrost as an additional driving factor for the extreme fire event in the boreal Baikal region in 2003

    Science.gov (United States)

    Forkel, M.; Thonicke, K.; Beer, C.; Cramer, W.; Bartalev, S.; Schmullius, C.

    2012-04-01

    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 degrade the forest, affect human values, emit huge amount of carbon and aerosols and alter the land surface albedo. Usually, wind, slope, and dry conditions have been recognized as factors determining fire spread. In the Baikal region, 127,000 km2 burned in 2003, while the annual average burned area is approx. 8100 km2. In average years, 16% of the burned area occurred in the continuous permafrost zone but in 2003, 33% of these burned areas coincide with the existence of permanently frozen grounds. Permafrost and the associated upper active layer, which thaws during summer and refreezes during winter, is an important supply for soil moisture in boreal ecosystems. This leads to the question if permafrost hydrology is a potential additional driving factor for extreme fire events in boreal forests. Using temperature and precipitation data, we calculated the Nesterov index as indicator for fire weather conditions. Further, we used satellite observations of burned area and surface moisture, a digital elevation model, a land cover and a permafrost map to evaluate drivers for the temporal dynamic and spatial variability of surface moisture conditions and burned area in spring 2003. On the basis of time series decomposition, we separated the effect of drivers for fire activity on different time scales. We next computed cross-correlations to identify potential time lags between weather conditions, surface moisture and fire activity. Finally, we assessed the predictive capability of different combinations of driving variables for surface moisture conditions and burned area using multivariate spatial-temporal regression models. The results from this study demonstrate that permafrost in larch-dominated ecosystems regulates the inter-annual variability of surface moisture and thus increases the inter

  4. Permafrost collapse shifts alpine tundra to a carbon source but reduces N2O and CH4 release on the northern Qinghai-Tibetan Plateau

    Science.gov (United States)

    Mu, C. C.; Abbott, B. W.; Zhao, Q.; Su, H.; Wang, S. F.; Wu, Q. B.; Zhang, T. J.; Wu, X. D.

    2017-09-01

    Important unknowns remain about how abrupt permafrost collapse (thermokarst) affects carbon balance and greenhouse gas flux, limiting our ability to predict the magnitude and timing of the permafrost carbon feedback. We measured monthly, growing-season fluxes of CO2, CH4, and N2O at a large thermokarst feature in alpine tundra on the northern Qinghai-Tibetan Plateau (QTP). Thermokarst formation disrupted plant growth and soil hydrology, shifting the ecosystem from a growing-season carbon sink to a weak source but decreasing feature level CH4 and N2O flux. Temperature-corrected ecosystem respiration from decomposing permafrost soil was 2.7 to 9.5-fold higher than in similar features from Arctic and Boreal regions, suggesting that warmer and dryer conditions on the northern QTP could accelerate carbon decomposition following permafrost collapse. N2O flux was similar to the highest values reported for Arctic ecosystems and was 60% higher from exposed mineral soil on the feature floor, confirming Arctic observations of coupled nitrification and denitrification in collapsed soils. Q10 values for respiration were typically over 4, suggesting high-temperature sensitivity of thawed carbon. Taken together, these results suggest that QTP permafrost carbon in alpine tundra is highly vulnerable to mineralization following thaw, and that N2O production could be an important noncarbon permafrost climate feedback. Permafrost collapse altered soil hydrology, shifting the ecosystem from a carbon sink to carbon source but decreasing CH4 and N2O flux. Little to no vegetation recovery after stabilization suggests potentially large net carbon losses. High N2O flux compared to Arctic and Boreal systems suggests noncarbon permafrost climate feedback.

  5. The International Permafrost Association: current initiatives for cryospheric research

    Science.gov (United States)

    Schollaen, Karina; Lewkowicz, Antoni G.; Christiansen, Hanne H.; Romanovsky, Vladimir E.; Lantuit, Hugues; Schrott, Lothar; Sergeev, Dimitry; Wei, Ma

    2015-04-01

    The International Permafrost Association (IPA), founded in 1983, has as its objectives to foster the dissemination of knowledge concerning permafrost and to promote cooperation among persons and national or international organizations engaged in scientific investigation and engineering work on permafrost. The IPA's primary responsibilities are convening International Permafrost Conferences, undertaking special projects such as preparing databases, maps, bibliographies, and glossaries, and coordinating international field programs and networks. Membership is through adhering national or multinational organizations or as individuals in countries where no Adhering Body exists. The IPA is governed by its Executive Committee and a Council consisting of representatives from 26 Adhering Bodies having interests in some aspect of theoretical, basic and applied frozen ground research, including permafrost, seasonal frost, artificial freezing and periglacial phenomena. This presentation details the IPA core products, achievements and activities as well as current projects in cryospheric research. One of the most important core products is the circumpolar permafrost map. The IPA also fosters and supports the activities of the Global Terrestrial Network on Permafrost (GTN-P) sponsored by the Global Terrestrial Observing System, GTOS, and the Global Climate Observing System, GCOS, whose long-term goal is to obtain a comprehensive view of the spatial structure, trends, and variability of changes in the active layer thickness and permafrost temperature. A further important initiative of the IPA are the biannually competitively-funded Action Groups which work towards the production of well-defined products over a period of two years. Current IPA Action Groups are working on highly topical and interdisciplinary issues, such as the development of a regional Palaeo-map of Permafrost in Eurasia, the integration of multidisciplinary knowledge about the use of thermokarst and permafrost

  6. Isotropic thaw subsidence in undisturbed permafrost landscapes

    Science.gov (United States)

    Shiklomanov, Nikolay I.; Streletskiy, Dmitry A.; Little, Jonathon D.; Nelson, Frederick E.

    2013-12-01

    in undisturbed terrain within some regions of the Arctic reveal limited correlation between increasing air temperature and the thickness of the seasonally thawed layer above ice-rich permafrost. Here we describe landscape-scale, thaw-induced subsidence lacking the topographic contrasts associated with thermokarst terrain. A high-resolution, 11 year record of temperature and vertical movement at the ground surface from contrasting physiographic regions of northern Alaska, obtained with differential global positioning systems technology, indicates that thaw of an ice-rich layer at the top of permafrost has produced decimeter-scale subsidence extending over the entire landscapes. Without specialized observation techniques the subsidence is not apparent to observers at the surface. This "isotropic thaw subsidence" explains the apparent stability of active layer thickness records from some landscapes of northern Alaska, despite warming near-surface air temperatures. Integrated over extensive regions, it may be responsible for thawing large volumes of carbon-rich substrate and could have negative impacts on infrastructure.

  7. Uncertainty in Arctic hydrology projections and the permafrost-carbon feedback

    Science.gov (United States)

    Andresen, C. G.; Lawrence, D. M.; Wilson, C. J.; McGuire, D.

    2017-12-01

    Projected warming is expected to thaw permafrost soils and deepen the permafrost active layer. These changes will affect surface hydrological conditions. Since the soil hydrologic state exerts a strong influence on the rate and pathway of soil organic matter decomposition into CO2 or CH4, there is a strong need to examine and better understand model projections of hydrologic change and how differences in process representation affect projections of wetting and/or drying of changing permafrost landscapes. This study aims to advance understanding of where, when and why arctic will become wetter or drier. We assessed simulations from 8 "permafrost enabled" land models that were run in offline mode from 1960 to 2299 forced with the same projected climate for a high-emissions scenario. Climate models project increased precipitation (P) across most of the Arctic domain and the land models indicate that runoff and evapotranspiration (ET) will also both increase. In general, the water input to the soil (P-ET) also increases, but the models project a contradicting long-term drying of the surface soil. The surface drying in the models can generally be explained by filtration of moisture to deeper soil layers as the active layer deepens or by increased sub-surface drainage where permafrost in a grid cell thaws completely. Though, there is a qualitative agreement in this type of response across the models, the projections vary dramatically in magnitude. Variability among simulations is largely attributed to parameterization and structural differences across the participating models, particularly the diverse representations of evapotranspiration, water table and soil water storage and transmission. A limited set of results from single forcing experiments suggests that the warming effect in the sensitivity analysis was the principal driver of soil drying while CO2 and precipitation effects had a small wetting influence. When compared to observational data, simulations tend to

  8. Anaerobic methanotrophic communities thrive in deep submarine permafrost.

    Science.gov (United States)

    Winkel, Matthias; Mitzscherling, Julia; Overduin, Pier P; Horn, Fabian; Winterfeld, Maria; Rijkers, Ruud; Grigoriev, Mikhail N; Knoblauch, Christian; Mangelsdorf, Kai; Wagner, Dirk; Liebner, Susanne

    2018-01-22

    Thawing submarine permafrost is a source of methane to the subsurface biosphere. Methane oxidation in submarine permafrost sediments has been proposed, but the responsible microorganisms remain uncharacterized. We analyzed archaeal communities and identified distinct anaerobic methanotrophic assemblages of marine and terrestrial origin (ANME-2a/b, ANME-2d) both in frozen and completely thawed submarine permafrost sediments. Besides archaea potentially involved in anaerobic oxidation of methane (AOM) we found a large diversity of archaea mainly belonging to Bathyarchaeota, Thaumarchaeota, and Euryarchaeota. Methane concentrations and δ 13 C-methane signatures distinguish horizons of potential AOM coupled either to sulfate reduction in a sulfate-methane transition zone (SMTZ) or to the reduction of other electron acceptors, such as iron, manganese or nitrate. Analysis of functional marker genes (mcrA) and fluorescence in situ hybridization (FISH) corroborate potential activity of AOM communities in submarine permafrost sediments at low temperatures. Modeled potential AOM consumes 72-100% of submarine permafrost methane and up to 1.2 Tg of carbon per year for the total expected area of submarine permafrost. This is comparable with AOM habitats such as cold seeps. We thus propose that AOM is active where submarine permafrost thaws, which should be included in global methane budgets.

  9. Tundra permafrost thaw causes significant shifts in energy partitioning

    Directory of Open Access Journals (Sweden)

    Christian Stiegler

    2016-04-01

    Full Text Available Permafrost, a key component of the arctic and global climate system, is highly sensitive to climate change. Observed and ongoing permafrost degradation influences arctic hydrology, ecology and biogeochemistry, and models predict that rapid warming is expected to significantly reduce near-surface permafrost and seasonally frozen ground during the 21st century. These changes raise concern of how permafrost thaw affects the exchange of water and energy with the atmosphere. However, associated impacts of permafrost thaw on the surface energy balance and possible feedbacks on the climate system are largely unknown. In this study, we show that in northern subarctic Sweden, permafrost thaw and related degradation of peat plateaus significantly change the surface energy balance of three peatland complexes by enhancing latent heat flux and, to less degree, also ground heat flux at the cost of sensible heat flux. This effect is valid at all radiation levels but more pronounced at higher radiation levels. The observed differences in flux partitioning mainly result from the strong coupling between soil moisture availability, vegetation composition, albedo and surface structure. Our results suggest that ongoing and predicted permafrost degradation in northern subarctic Sweden ultimately result in changes in land–atmosphere coupling due to changes in the partitioning between latent and sensible heat fluxes. This in turn has crucial implications for how predictive climate models for the Arctic are further developed.

  10. Permafrost stores a globally significant amount of mercury

    Science.gov (United States)

    Schuster, Paul F.; Schaefer, Kevin; Aiken, George R.; Antweiler, Ronald C.; DeWild, John F.; Gryziec, Joshua D.; Gusmeroli, Alessio; Hugelius, Gustaf; Jafarov, Elchin E.; Krabbenhoft, David P.; Liu, Lin; Herman-Mercer, Nicole M.; Mu, Cuicui; Roth, David A.; Schaefer, Tim; Striegl, Robert G.; Wickland, Kimberly P.; Zhang, Tingjun

    2018-01-01

    Changing climate in northern regions is causing permafrost to thaw with major implications for the global mercury (Hg) cycle. We estimated Hg in permafrost regions based on in situ measurements of sediment total mercury (STHg), soil organic carbon (SOC), and the Hg to carbon ratio (RHgC) combined with maps of soil carbon. We measured a median STHg of 43 ± 30 ng Hg g soil−1 and a median RHgC of 1.6 ± 0.9 μg Hg g C−1, consistent with published results of STHg for tundra soils and 11,000 measurements from 4,926 temperate, nonpermafrost sites in North America and Eurasia. We estimate that the Northern Hemisphere permafrost regions contain 1,656 ± 962 Gg Hg, of which 793 ± 461 Gg Hg is frozen in permafrost. Permafrost soils store nearly twice as much Hg as all other soils, the ocean, and the atmosphere combined, and this Hg is vulnerable to release as permafrost thaws over the next century. Existing estimates greatly underestimate Hg in permafrost soils, indicating a need to reevaluate the role of the Arctic regions in the global Hg cycle.

  11. Geophysical mapping of deep permafrost change after disturbance

    Science.gov (United States)

    Minsley, B. J.; Pastick, N. J.; Wylie, B. K.; Kass, A.; Brown, D. N.; Rey, D.; Bloss, B. R.; Ebel, B. A.; Walvoord, M. A.; Emond, A.; Daanen, R. P.

    2017-12-01

    Disturbance related to fire or hydrologic processes can cause degradation of deep (greater than 1 m) permafrost. These changes in deep permafrost have the potential to impact landscapes and infrastructure, alter the routing and distribution of surface water or groundwater, and may contribute to the flux of carbon to terrestrial and aquatic ecosystems. However, characterization of deep permafrost over large areas and with high spatial resolution is not possible with traditional remote sensing or surface observations. We make use of multiple ground-based and airborne geophysical methods, as well as numerical simulations, to better understand the distribution of permafrost and how it has changed after disturbance. At the local scale, electrical resistivity tomography (ERT) measurements are used to identify changes in permafrost characteristics to depths of up to 15 m along more than 40 100-200 m-long transects collected in interior Alaska. At select locations along these profiles, measurements of downhole nuclear magnetic resonance were made to depths of 2 m belowground in order to quantify in situ unfrozen water content and soil texture that help to constrain ERT interpretations. At the regional scale, airborne and ground-based electromagnetic data have been acquired to map the complex distribution of deep permafrost beneath and adjacent to the many lakes and streams in parts of interior Alaska. Together, these geophysical datasets help to fill a critical gap in understanding permafrost landscapes and their response to disturbance.

  12. Permafrost Stores a Globally Significant Amount of Mercury

    Science.gov (United States)

    Schuster, Paul F.; Schaefer, Kevin M.; Aiken, George R.; Antweiler, Ronald C.; Dewild, John F.; Gryziec, Joshua D.; Gusmeroli, Alessio; Hugelius, Gustaf; Jafarov, Elchin; Krabbenhoft, David P.; Liu, Lin; Herman-Mercer, Nicole; Mu, Cuicui; Roth, David A.; Schaefer, Tim; Striegl, Robert G.; Wickland, Kimberly P.; Zhang, Tingjun

    2018-02-01

    Changing climate in northern regions is causing permafrost to thaw with major implications for the global mercury (Hg) cycle. We estimated Hg in permafrost regions based on in situ measurements of sediment total mercury (STHg), soil organic carbon (SOC), and the Hg to carbon ratio (RHgC) combined with maps of soil carbon. We measured a median STHg of 43 ± 30 ng Hg g soil-1 and a median RHgC of 1.6 ± 0.9 μg Hg g C-1, consistent with published results of STHg for tundra soils and 11,000 measurements from 4,926 temperate, nonpermafrost sites in North America and Eurasia. We estimate that the Northern Hemisphere permafrost regions contain 1,656 ± 962 Gg Hg, of which 793 ± 461 Gg Hg is frozen in permafrost. Permafrost soils store nearly twice as much Hg as all other soils, the ocean, and the atmosphere combined, and this Hg is vulnerable to release as permafrost thaws over the next century. Existing estimates greatly underestimate Hg in permafrost soils, indicating a need to reevaluate the role of the Arctic regions in the global Hg cycle.

  13. Palaeoclimate characteristics in interior Siberia of MIS 6-2: first insights from the Batagay permafrost mega-thaw slump in the Yana Highlands

    Science.gov (United States)

    Ashastina, Kseniia; Schirrmeister, Lutz; Fuchs, Margret; Kienast, Frank

    2017-07-01

    Syngenetic permafrost deposits formed extensively on and around the arising Beringian subcontinent during the Late Pleistocene sea level lowstands. Syngenetic deposition implies that all material, both mineral and organic, freezes parallel to sedimentation and remains frozen until degradation of the permafrost. Permafrost is therefore a unique archive of Late Pleistocene palaeoclimate. Most studied permafrost outcrops are situated in the coastal lowlands of northeastern Siberia; inland sections are, however, scarcely available. Here, we describe the stratigraphical, cryolithological, and geochronological characteristics of a permafrost sequence near Batagay in the Siberian Yana Highlands, the interior of the Sakha Republic (Yakutia), Russia, with focus on the Late Pleistocene Yedoma ice complex (YIC). The recently formed Batagay mega-thaw slump exposes permafrost deposits to a depth of up to 80 m and gives insight into a climate record close to Verkhoyansk, which has the most severe continental climate in the Northern Hemisphere. Geochronological dating (optically stimulated luminescence, OSL, and 14C ages) and stratigraphic implications delivered a temporal frame from the Middle Pleistocene to the Holocene for our sedimentological interpretations and also revealed interruptions in the deposition. The sequence of lithological units indicates a succession of several distinct climate phases: a Middle Pleistocene ice complex indicates cold stage climate. Then, ice wedge growth stopped due to highly increased sedimentation rates and eventually a rise in temperature. Full interglacial climate conditions existed during accumulation of an organic-rich layer - plant macrofossils reflected open forest vegetation existing under dry conditions during Marine Isotope Stage (MIS) 5e. The Late Pleistocene YIC (MIS 4-MIS 2) suggests severe cold-stage climate conditions. No alas deposits, potentially indicating thermokarst processes, were detected at the site. A detailed comparison

  14. Palaeoclimate characteristics in interior Siberia of MIS 6–2: first insights from the Batagay permafrost mega-thaw slump in the Yana Highlands

    Directory of Open Access Journals (Sweden)

    K. Ashastina

    2017-07-01

    Full Text Available Syngenetic permafrost deposits formed extensively on and around the arising Beringian subcontinent during the Late Pleistocene sea level lowstands. Syngenetic deposition implies that all material, both mineral and organic, freezes parallel to sedimentation and remains frozen until degradation of the permafrost. Permafrost is therefore a unique archive of Late Pleistocene palaeoclimate. Most studied permafrost outcrops are situated in the coastal lowlands of northeastern Siberia; inland sections are, however, scarcely available. Here, we describe the stratigraphical, cryolithological, and geochronological characteristics of a permafrost sequence near Batagay in the Siberian Yana Highlands, the interior of the Sakha Republic (Yakutia, Russia, with focus on the Late Pleistocene Yedoma ice complex (YIC. The recently formed Batagay mega-thaw slump exposes permafrost deposits to a depth of up to 80 m and gives insight into a climate record close to Verkhoyansk, which has the most severe continental climate in the Northern Hemisphere. Geochronological dating (optically stimulated luminescence, OSL, and 14C ages and stratigraphic implications delivered a temporal frame from the Middle Pleistocene to the Holocene for our sedimentological interpretations and also revealed interruptions in the deposition. The sequence of lithological units indicates a succession of several distinct climate phases: a Middle Pleistocene ice complex indicates cold stage climate. Then, ice wedge growth stopped due to highly increased sedimentation rates and eventually a rise in temperature. Full interglacial climate conditions existed during accumulation of an organic-rich layer – plant macrofossils reflected open forest vegetation existing under dry conditions during Marine Isotope Stage (MIS 5e. The Late Pleistocene YIC (MIS 4–MIS 2 suggests severe cold-stage climate conditions. No alas deposits, potentially indicating thermokarst processes, were detected at the

  15. Sensitivity of airborne geophysical data to sublacustrine and near-surface permafrost thaw

    Science.gov (United States)

    Minsley, Burke J.; Wellman, Tristan; Walvoord, Michelle Ann; Revil, Andre

    2014-01-01

    A coupled hydrogeophysical forward and inverse modeling approach is developed to illustrate the ability of frequency-domain airborne electromagnetic (AEM) data to characterize subsurface physical properties associated with sublacustrine permafrost thaw during lake-talik formation. Numerical modeling scenarios are evaluated that consider non-isothermal hydrologic responses to variable forcing from different lake depths and for different hydrologic gradients. A novel physical property relationship connects the dynamic distribution of electrical resistivity to ice saturation and temperature outputs from the SUTRA groundwater simulator with freeze–thaw physics. The influence of lithology on electrical resistivity is controlled by a surface conduction term in the physical property relationship. Resistivity models, which reflect changes in subsurface conditions, are used as inputs to simulate AEM data in order to explore the sensitivity of geophysical observations to permafrost thaw. Simulations of sublacustrine talik formation over a 1000-year period are modeled after conditions found in the Yukon Flats, Alaska. Synthetic AEM data are analyzed with a Bayesian Markov chain Monte Carlo algorithm that quantifies geophysical parameter uncertainty and resolution. Major lithological and permafrost features are well resolved by AEM data in the examples considered. The subtle geometry of partial ice saturation beneath lakes during talik formation cannot be resolved using AEM data, but the gross characteristics of sub-lake resistivity models reflect bulk changes in ice content and can identify the presence of a talik. A final synthetic example compares AEM and ground-based electromagnetic responses for their ability to resolve shallow permafrost and thaw features in the upper 1–2 m below ground outside the lake margin.

  16. Diminishing friction of joint surfaces as initiating factor for destabilising permafrost rocks?

    Science.gov (United States)

    Funk, Daniel; Krautblatter, Michael

    2010-05-01

    Degrading alpine permafrost due to changing climate conditions causes instabilities in steep rock slopes. Due to a lack in process understanding, the hazard is still difficult to asses in terms of its timing, location, magnitude and frequency. Current research is focused on ice within joints which is considered to be the key-factor. Monitoring of permafrost-induced rock failure comprises monitoring of temperature and moisture in rock-joints. The effect of low temperatures on the strength of intact rock and its mechanical relevance for shear strength has not been considered yet. But this effect is signifcant since compressive and tensile strength is reduced by up to 50% and more when rock thaws (Mellor, 1973). We hypotheisze, that the thawing of permafrost in rocks reduces the shear strength of joints by facilitating the shearing/damaging of asperities due to the drop of the compressive/tensile strength of rock. We think, that decreasing surface friction, a neglected factor in stability analysis, is crucial for the onset of destabilisation of permafrost rocks. A potential rock slide within the permafrost zone in the Wetterstein Mountains (Zugspitze, Germany) is the basis for the data we use for the empirical joint model of Barton (1973) to estimate the peak shear strength of the shear plane. Parameters are the JRC (joint roughness coefficient), the JCS (joint compressive strength) and the residual friction angle (φr). The surface roughness is measured in the field with a profile gauge to create 2D-profiles of joint surfaces. Samples of rock were taken to the laboratory to measure compressive strength using a high-impact Schmidt-Hammer under air-dry, saturated and frozen conditions on weathered and unweathered surfaces. Plugs where cut out of the rock and sand blasted for shear tests under frozen and unfrozen conditions. Peak shear strength of frozen and unfrozen rocks will be calculated using Barton's model. First results show a mean decrease of compressive

  17. Permafrost Degradation Risk Zone Assessment using Simulation Models

    DEFF Research Database (Denmark)

    Daanen, R.P.; Ingeman-Nielsen, Thomas; Marchenko, S.

    2011-01-01

    as the potential active layer increase due to climate warming and surface alterations. PTP is then used in a simple risk assessment procedure useful for engineering applications. The modelling shows that climate warming will result in continuing wide-spread permafrost warming and degradation in Greenland......In this proof-of-concept study we focus on linking large scale climate and permafrost simulations to small scale engineering projects by bridging the gap between climate and permafrost sciences on the one hand and on the other technical recommendation for adaptation of planned infrastructures...

  18. Improving permafrost distribution modelling using feature selection algorithms

    Science.gov (United States)

    Deluigi, Nicola; Lambiel, Christophe; Kanevski, Mikhail

    2016-04-01

    The availability of an increasing number of spatial data on the occurrence of mountain permafrost allows the employment of machine learning (ML) classification algorithms for modelling the distribution of the phenomenon. One of the major problems when dealing with high-dimensional dataset is the number of input features (variables) involved. Application of ML classification algorithms to this large number of variables leads to the risk of overfitting, with the consequence of a poor generalization/prediction. For this reason, applying feature selection (FS) techniques helps simplifying the amount of factors required and improves the knowledge on adopted features and their relation with the studied phenomenon. Moreover, taking away irrelevant or redundant variables from the dataset effectively improves the quality of the ML prediction. This research deals with a comparative analysis of permafrost distribution models supported by FS variable importance assessment. The input dataset (dimension = 20-25, 10 m spatial resolution) was constructed using landcover maps, climate data and DEM derived variables (altitude, aspect, slope, terrain curvature, solar radiation, etc.). It was completed with permafrost evidences (geophysical and thermal data and rock glacier inventories) that serve as training permafrost data. Used FS algorithms informed about variables that appeared less statistically important for permafrost presence/absence. Three different algorithms were compared: Information Gain (IG), Correlation-based Feature Selection (CFS) and Random Forest (RF). IG is a filter technique that evaluates the worth of a predictor by measuring the information gain with respect to the permafrost presence/absence. Conversely, CFS is a wrapper technique that evaluates the worth of a subset of predictors by considering the individual predictive ability of each variable along with the degree of redundancy between them. Finally, RF is a ML algorithm that performs FS as part of its

  19. Towards Sustainable Urban Planning Through Transit-Oriented Development (A Case Study: Tehran

    Directory of Open Access Journals (Sweden)

    Hamid Motieyan

    2017-12-01

    Full Text Available Sustainable development is regarded as a pivotal factor for smart urban planning. Transit-Oriented Development (TOD is a well-known land use transportation integration (LUTI planning method, which can fulfill sustainable development objectives. In this study, a new spatial index is developed to measure TOD levels in neighborhoods of Tehran, the capital of Iran. To develop the TOD index, several criteria and indicators are first computed using spatial analyses, before being aggregated using a fuzzy-analytic hierarchy process (fuzzy-AHP. The fuzzy-AHP method generates three types of factor maps: that are optimistic, pessimistic, and moderate. This process evaluates the sensitivity of the TOD index by determining the indicators’ weights from various views, or perspectives. The results of this sensitivity analysis show the robustness of results from various views. Furthermore, in order to assess the efficiency of the proposed method, the moderate TOD-level map is compared with both the level of public transit services and trip attraction in neighborhoods. This comparison shows that the TOD map has an accuracy of 77 percent in urban modeling, which verifies the efficiency of the proposed method for measuring TOD.

  20. Stakeholder Deliberation on Developing Affordable Housing Strategies: Towards Inclusive and Sustainable Transit-Oriented Developments

    Directory of Open Access Journals (Sweden)

    Jyothi Chava

    2016-10-01

    Full Text Available Transit-oriented developments (TODs are commanding high land and rental values due to improved accessibility and economic opportunities. Owing to the increase in land and rental values, the highly desirable TODs are gradually becoming inaccessible to the poor, creating social exclusion and housing inequities within the TODs. To address this consequence, the study proposes a three-level stakeholder deliberation framework (inform, involve, and collaborate towards developing inclusive housing strategies for equitable and sustainable TODs. The framework is applied to the context of the Yeshwanthpur industrial area, Bengaluru, India. The first level of deliberation, ‘information’, foregrounds the need for affordable housing strategies for stakeholders. In the second level of deliberation, the stakeholders involved identify the major challenges in incorporating affordable housing into TODs. In the third level of deliberation, stakeholders collaborate to contemplate strategies to combat each challenge. The results show that mandatory inclusionary zoning, special-purpose planning vehicles, land banking entities, innovative financing tools, and local area level plans in collaboration with the community, emerged as potentially feasible strategies to create inclusive housing outcomes in the TOD case study area.

  1. Peripheral nerve injury induces a transitory microglial reaction in the rat infralimbic cortex.

    Science.gov (United States)

    Chu Sin Chung, Paul; Panigada, Tania; Cardis, Romain; Decosterd, Isabelle; Gosselin, Romain-Daniel

    2017-08-10

    Undeniable evidence shows that microglia in the spinal cord undergo marked reactions following peripheral injuries. However, only rare studies have investigated the possible short and long term microglial reaction in brain regions following peripheral nerve injury and its interspecies specificities. In the present study we examined microglia in subdivisions of the prefrontal cortex in mice and rats, 7days and 42days after spared nerve injury (SNI) of the sciatic nerve. We show that a bilateral increase of microglial density takes place in the infralimbic cortex in rats 7days post-injury (sham vs. SNI, n=5: ipsilateral 35.4% increase of the median, p=0.0317; contralateral 24.9% increase of the median, p=0.0079), without any detectable change in the other investigated regions, namely the anterior cingulate, prelimbic and agranular insular cortices. In mice, no observable difference could be found in any region at both time points, neither using Iba-1 immunostaining nor with CX3CR1-eGFP animals. Our results indicate that a transitory, species-specific and highly regionalized microglial reaction takes place in the prefrontal cortex following peripheral nerve injury. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Rapid and transitory stimulation of 3-O-methylglucose transport by growth hormone

    International Nuclear Information System (INIS)

    Carter-Su, C.; Rozsa, F.W.; Wang, Xueyan; Stubbart, J.R.

    1988-01-01

    The regulation of hexose transport by growth hormone (GH) was investigated using isolated rat adipocytes. GH caused a rapid (<3 min) rise in rates of 3-O-methylglucose transport that reached a maximum of two to six times the basal rates in 10-30 min. The stimulation of transport was transitory, and rates of transport started to decline 15-30 min after GH was added. Transport stimulation required a period of preincubation; no stimulation was observed in freshly isolated cells. GH stimulated hexose transport between 100 and 5,000 ng/ml, with a 50% effective dose between 200 and 300 ng/ml. Depletion of cellular ATP by 2,4-dinitrophenol blocked the ability of GH to stimulate transport but not the decline of transport rates following stimulation by GH. In contrast, an inhibitor of RNA synthesis, actinomycin D, had no effect on either the initial stimulation by GH or the initial subsequent decline of transport when added simultaneously or 15 min prior to GH. Actinomycin D did, however, cause a second rise in hexose transport at ∼120 min that was blocked by 2,4-dinitrophenol. These results suggest that changes in glucose transport contribute to the effects of GH on carbohydrate and lipid metabolism in adipose tissue. These changes are rapid, of substantial magnitude, and of a complex nature, suggesting that regulation of glucose transport by GH most likely involves multiple mechanisms

  3. Integrating Regret Psychology to Travel Mode Choice for a Transit-Oriented Evacuation Strategy

    Directory of Open Access Journals (Sweden)

    Shi An

    2015-06-01

    Full Text Available Facing the potential dangers from sudden disasters in urban cities, emergency administrators have to make an appropriate evacuation plan to mitigate negative consequences. However, little attention has been paid to evacuee real decision psychology when developing a strategy. The aim of this paper is to analyze evacuee mode choice behavior considering regret aversion psychology during evacuation. First, the utility-based and regret-based models are formulated to obtain evacuees’ preferences on travel mode choice, respectively. According to the data collected from the stated preference (SP survey on evacuee mode choice, the estimation results show that the regret-based model performs better than the utility model. Moreover, based on the estimates from behavioral analysis, the elasticities of evacuee mode choices are calculated, and transit strategy simulation is undertaken to investigate the influence on evacuee mode switching from private automobile to public transit. The results are expected to help emergency administrators to make a transit-oriented strategy for a sustainable evacuation plan, especially for the benefit of carless people.

  4. Effect of permafrost on the formation of organic carbon pools and their physical-chemical properties in the Eastern Swiss Alps

    Science.gov (United States)

    Pichler, B.; Alewell, C.; Kneisel, C.; Meusburger, K.; Egli, M.

    2012-04-01

    Alpine soils contain a relatively large amount of organic matter (OM) even at elevations above the present-days timberline. Current climatic conditions and the occurrence of discontinuous and sporadic permafrost in the mountains result in a low turnover rate and therefore accumulation of OM. Alpine ecosystems are highly sensitive to environmental changes and therefore may become a potential source of atmospheric carbon dioxide (CO2) due to global warming. The expected changes in thermal and hydrological conditions in permafrost soils will not only influence OM degradation processes within the soil. Especially in alpine regions, soil erosion processes might be affected and potentially promote the mineralization of OM. However, the knowledge about the biogeochemistry and OM-stabilization processes and rates in permafrost soils in alpine regions is scarce, which makes it difficult to predict climate-carbon feedbacks. Our aim is to determine and compare the quantity, allocation and mean residence time of OM and the potential erosion processes in permafrost soils and adjacent unfrozen soils (distance between permafrost/non-permafrost soils max. 200m) at three locations in the Eastern Swiss Alps (Val Bever, Albula). Bulk soil, labile (oxidized by H2O2) and stable fractions (H2O2-resistant) were analyzed for their C-content and characterized using DRIFT (Diffuse Reflection Infrared Fourier Transform). Additionally, selected soil samples were 14C-dated. This approach has been applied for the first time in high alpine regions. To estimate the degree of disturbance, soil erosion has been qualitatively assessed by relating the OM-delta13C values of the soil profiles of interest to undisturbed reference profiles. We found rather well-developed soil profiles and a relatively high amount of OM at both types of sites (permafrost/non-permafrost), leading to the assumption that these soils developed over a certain period under a different (warmer) climate. This fact is supported by

  5. Collapsing permafrost coasts in the Arctic

    Science.gov (United States)

    Fritz, Michael; Lantuit, Hugues

    2017-04-01

    Arctic warming is exposing permafrost coastlines, which account for 34% of the Earth's coasts, to rapid thaw and erosion. Coastal erosion rates as high as 25 m yr-1 together with the large amount of organic matter frozen in permafrost are resulting in an annual release of 14.0 Tg (1012 gram) particulate organic carbon into the nearshore zone. The nearshore zone is the primary recipient of higher fluxes of carbon and nutrients from thawing permafrost. We highlight the crucial role the nearshore zone plays in Arctic biogeochemical cycling, as here the fate of the released material is determined to: (1) degrade into greenhouse gases, (2) fuel marine primary production, (3) be buried in nearshore sediments or (4) be transported offshore. With Arctic warming, coastal erosion fluxes have the potential to increase by an order of magnitude until 2100. Such increases would result in drastic impacts on global carbon fluxes and their climate feedbacks, on nearshore food webs and on local communities, whose survival still relies on marine biological resources. Quantifying the potential impacts of increasing erosion on coastal ecosystems is crucial for food security of northern residents living in Arctic coastal communities. We need to know how the traditional hunting and fishing grounds might be impacted by high loads of sediment and nutrients released from eroding coasts, and to what extent coastal retreat will lead to a loss of natural habitat. Quantifying fluxes of organic carbon and nutrients is required, both in nearshore deposits and in the water column by sediment coring and systematic oceanographic monitoring. Ultimately, this will allow us to assess the transport and degradation pathways of sediment and organic matter derived from erosion. We need to follow the complete pathway, which is multi-directional including atmospheric release, lateral transport, transitional retention in the food web, and ultimate burial in seafloor sediments. We present numbers of multi

  6. Transitory cognitive impairment with brief generalized spike-wave paroxysm: a clinical counterexample to the three-second rule.

    Science.gov (United States)

    Mendizabal, J E; Nowack, W J

    1996-10-01

    The topic of transitory impairment of consciousness with spike wave bursts has been of interest to neurologists for years. Based on some early experiments, a 3-second rule was formulated and has found its way into the conventional wisdom of neurology. It states that, in order to result in impairment of consciousness, a spike-wave burst must be of at least 3 seconds' duration. We discuss a case which poses a clinical counterexample to that rule.

  7. Wetland succession in a permafrost collapse: interactions between fire and thermokarst

    Directory of Open Access Journals (Sweden)

    I. H. Myers-Smith

    2008-09-01

    Full Text Available To determine the influence of fire and thermokarst in a boreal landscape, we investigated peat cores within and adjacent to a permafrost collapse feature on the Tanana River Floodplain of Interior Alaska. Radioisotope dating, diatom assemblages, plant macrofossils, charcoal fragments, and carbon and nitrogen content of the peat profile indicate ~600 years of vegetation succession with a transition from a terrestrial forest to a sedge-dominated wetland over 100 years ago, and to a Sphagnum-dominated peatland in approximately 1970. The shift from sedge to Sphagnum, and a decrease in the detrended tree-ring width index of black spruce trees adjacent to the collapse coincided with an increase in the growing season temperature record from Fairbanks. This concurrent wetland succession and reduced growth of black spruce trees indicates a step-wise ecosystem-level response to a change in regional climate. In 2001, fire was observed coincident with permafrost collapse and resulted in lateral expansion of the peatland. These observations and the peat profile suggest that future warming and/or increased fire disturbance could promote permafrost degradation, peatland expansion, and increase carbon storage across this landscape; however, the development of drought conditions could reduce the success of both black spruce and Sphagnum, and potentially decrease the long-term ecosystem carbon storage.

  8. Markers of Soil Organic Matter Transformation in Permafrost Peat Mounds of Northeastern Europe

    Science.gov (United States)

    Pastukhov, A. V.; Knoblauch, C.; Yakovleva, E. V.; Kaverin, D. A.

    2018-01-01

    For the paleoreconstruction of permafrost peat mounds and the identification of plant communities participating in the formation of peat, the contents of n-alkanes (C20-C33) have been determined, and relative changes in the stable isotope compositions of carbon and nitrogen and the C/N ratio have been analysed. Several indices ( CPI alkanes, P aq, P wax) have been calculated to assess the degree of decomposition of the peats studied and the contributions of different plant species to their formation. It has been found that shortand long-chain n-alkanes are concentrated in high-moor peat, while medium-chain alkanes are typical for transitional peat. Integrated analysis of the studied markers has shown that the botanical and material composition of peat, anaerobic conditions of bog formation, and permafrost play an important role in the preservation of organic carbon in permafrost peat mounds. Alternation of plant associations is the main reason for changes in n-alkane concentrations, C/N ratios, and δ13C values.

  9. Optimization of viral resuspension methods for carbon-rich soils along a permafrost thaw gradient

    Directory of Open Access Journals (Sweden)

    Gareth Trubl

    2016-05-01

    Full Text Available Permafrost stores approximately 50% of global soil carbon (C in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types of high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen. Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs g−1 of soil than other methods tested. All method combinations yielded VLPs g−1 of soil on the 108 order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g−1 of soil among the soil types. This research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.

  10. Seepage erosion of Arctic coastal bluffs driven by thawing permafrost in Northwest Alaska

    Science.gov (United States)

    Phillips, C. B.; Jerolmack, D. J.; Crosby, B. T.

    2010-12-01

    On the forefront of transient landscapes is the Arctic. Air and sea surface temperatures have increased significantly in the last 50 years due to anthropogenic warming, and have been blamed for observed accelerations in coastal erosion rates and the formation of thermokarst features. The controls that permafrost exerts on landforms and sediment transport are largely unknown, but may be elucidated by examining landscape response to permafrost thaw. Using current and historical aerial photos of Northwest Alaska we identified an area of coastal bluffs experiencing increased erosion. What makes this portion of the coast unusual is that erosion is not driven by thermomechanical action from waves, however waves are important in the removal of material from the base of the slump. Instead, retrogressive slump failures - which have seen accelerated growth in the 1900s - initiated the growth of headward cutting alcoves that have now penetrated up to a hundred meters inland. Our field topographic surveys reveal that slumps decrease in slope and increase in circularity with increasing size, suggesting a temporal growth progression toward an asymptotic quasi-circular planform shape. Morphometric scaling relationships suggest that groundwater seepage erosion may be driving alcove growth. Junction angles of alcoves, and the trajectories of headcutting measured from repeat aerial photography, also support a model of ground water competition as the primary mechanism of continued growth. Coastal erosion rates do not depend on solar radiation flux; we propose therefore that seepage water is derived from a vertical lowering of the permafrost table, by thaw resulting from increased ambient air temperatures. Slump features such as those observed here are expected to become more numerous on Arctic coastal and river bluffs in the approaching decades as mean summer air temperatures continue to rise. Thawing of permafrost shows how the Arctic landscape is out of equilibrium, eroding as a

  11. Permafrost collapse alters soil carbon stocks, respiration, CH4 , and N2O in upland tundra.

    Science.gov (United States)

    Abbott, Benjamin W; Jones, Jeremy B

    2015-12-01

    Release of greenhouse gases from thawing permafrost is potentially the largest terrestrial feedback to climate change and one of the most likely to occur; however, estimates of its strength vary by a factor of thirty. Some of this uncertainty stems from abrupt thaw processes known as thermokarst (permafrost collapse due to ground ice melt), which alter controls on carbon and nitrogen cycling and expose organic matter from meters below the surface. Thermokarst may affect 20-50% of tundra uplands by the end of the century; however, little is known about the effect of different thermokarst morphologies on carbon and nitrogen release. We measured soil organic matter displacement, ecosystem respiration, and soil gas concentrations at 26 upland thermokarst features on the North Slope of Alaska. Features included the three most common upland thermokarst morphologies: active-layer detachment slides, thermo-erosion gullies, and retrogressive thaw slumps. We found that thermokarst morphology interacted with landscape parameters to determine both the initial displacement of organic matter and subsequent carbon and nitrogen cycling. The large proportion of ecosystem carbon exported off-site by slumps and slides resulted in decreased ecosystem respiration postfailure, while gullies removed a smaller portion of ecosystem carbon but strongly increased respiration and N2 O concentration. Elevated N2 O in gully soils persisted through most of the growing season, indicating sustained nitrification and denitrification in disturbed soils, representing a potential noncarbon permafrost climate feedback. While upland thermokarst formation did not substantially alter redox conditions within features, it redistributed organic matter into both oxic and anoxic environments. Across morphologies, residual organic matter cover, and predisturbance respiration explained 83% of the variation in respiration response. Consistent differences between upland thermokarst types may contribute to the

  12. Application of 2-D geoelectrical resistivity tomography for mountain permafrost detection in sporadic permafrost environments: Experiences from Eastern Austria

    Science.gov (United States)

    Kellerer-Pirklbauer, Andreas

    2015-04-01

    Mountain permafrost covers some 2000 km² of the Austrian Alps which is less than 2.5% of the national territory. Delineating the altitudinal lower limit of permafrost in the mountains of Austria is difficult due the complex topography, the rather sparseness of field verification data and the lack of long-term permafrost monitoring data. Such monitoring data should cover different slope aspects, different elevations, different substrates and different mountain regions of Austria. In this study it was attempted to delineate the lower limit of permafrost at two study sites in the Tauern Range, Austria, applying two-dimensional geoelectrical resistivity tomography (ERT). In addition, multi-annual ground temperature data collected by miniature temperature datalogger (MDT) were used to validate the results. At the study site Hochreichart (maximum elevation 2416 m asl), located in the Seckauer Tauern Range, 14 ERT profiles (lengths 48-196 m; electrode spacing 2, 2.5 or 4 m) were measured at elevations between 1805 and 2416 m asl. Measurements were carried out at two cirques (Reichart, Schöneben) and at the summit plateau of Hochreichart. Results at this site indicate that permafrost lenses are detectable at elevations down to c.1900 m asl at radiation-sheltered sites. Furthermore, at the summit plateau permafrost only occurs as rather small lenses. The ERT-based permafrost pattern is generally confirmed by the MTD data with negative mean annual ground temperature values at only a few monitoring sites. However, the possibility of air-filled cavities causing higher resistive zones faking permafrost existence cannot be excluded because coarse-grained sediments (i.e. relict rock glaciers and autochthonous block fields) are widespread at this study site. At the second study site Kögele Cirque (maximum elevation 3030 m asl) located in the Schober Mountains 12 ERT profiles (lengths 48 m; electrode spacing 2 m) were measured at elevations between 2631 and 2740 m asl. Spatially

  13. The International University Courses on Permafrost (IUCP): an IPY Education Initiative From the International Permafrost Association (IPA)

    Science.gov (United States)

    Prick, A.; Christiansen, H. H.

    2006-12-01

    Worldwide, only very few dedicated permafrost courses exist at university level today. This significantly limits the development of new permafrost researchers. Therefore, the International Permafrost Association (IPA) has developed an overview of International University Courses on Permafrost (IUCP), as part of its participation in the IPY. This polar-related educational program covers cross-cutting activities of the four core IPY-IPA endorsed cluster projects that constitute the IPY Permafrost Programme: Permafrost Observatory Project: A Contribution to the Thermal State of Permafrost (TSP; Project 50); Antarctic and sub-Antarctic Permafrost, Periglacial and Soil Environments (ANTPAS; Project 33); Arctic Circumpolar Coastal Observatory Network (ACCO-Net; Project 90); Carbon Pools in Permafrost Regions (CAPP; Project 373). The IUCP collects information about existing and new IPY permafrost courses worldwide, to encourage a broad international student participation in the existing courses. All courses dealing with permafrost and periglacial geomorphology within the science and engineering disciplines and organized in 2007 to 2009 in both hemispheres qualify for IUCP. Some courses are exclusively field-based and take place in various polar regions, offering students a unique opportunity to gather field experience. Other courses are theoretical and classroom-based or include only limited time in the field. All course levels are taken into account, from undergraduate to doctorate level; the IPA also encourages young professional participation in the IUCP. IPA- IPY education coordinators in each country are providing relevant information. IUCP course information is presented on the IPA webpage. The use of web resource and search tools allow easy access to course contents. The IUCP course numbers by countries as by August 2006 is: Argentina (1), Belgium (1), Canada (29), China (11), Denmark (1), France (2), Japan (7), Mongolia (1), Netherlands (4), New Zealand (1

  14. Permafrost Active Layer Seismic Interferometry Experiment (PALSIE).

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knox, Hunter Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); James, Stephanie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Rebekah [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cole, Chris [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We present findings from a novel field experiment conducted at Poker Flat Research Range in Fairbanks, Alaska that was designed to monitor changes in active layer thickness in real time. Results are derived primarily from seismic data streaming from seven Nanometric Trillium Posthole seismometers directly buried in the upper section of the permafrost. The data were evaluated using two analysis methods: Horizontal to Vertical Spectral Ratio (HVSR) and ambient noise seismic interferometry. Results from the HVSR conclusively illustrated the method's effectiveness at determining the active layer's thickness with a single station. Investigations with the multi-station method (ambient noise seismic interferometry) are continuing at the University of Florida and have not yet conclusively determined active layer thickness changes. Further work continues with the Bureau of Land Management (BLM) to determine if the ground based measurements can constrain satellite imagery, which provide measurements on a much larger spatial scale.

  15. Permafrost Map for Northwestern Canada (Mackenzie Region), Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Permafrost Map for Northwestern Canada (Mackenzie Region) is a digital version of the 1:1,000,000 map produced by Heginbottom and Radburn [Heginbottom, J.A. and...

  16. Assessment of three mitigation techniques for permafrost protection

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr

    The presence of permafrost is an important aspect in civil engineering in arctic regions. The construction of engineering structures, such as road and airfield embankments, will change the thermal regime of the ground, and may lead to permafrost degradation under or adjacent to such structures....... This problem, has in the last decades, been amplified by the climate warming, which has been most evident in the arctic regions. The construction of a road embankment usually results in an increased mean annual surface temperature, which will increase the thawing of permafrost and expose the road embankment...... objective has been to study the three above-mentioned techniques and evaluate their potential for minimizing the problems with thaw settlements in permafrost areas. The air convection embankment and heat drain techniques have been tested for the implementation in the shoulders of road and airfield...

  17. Dalton Highway 9 to 11 Mile expedient resistivity permafrost investigation.

    Science.gov (United States)

    2014-01-01

    This project performed capacitive coupled resistivity surveys over a roadway reconstruction project in Interior Alaska, for the determination of permafrost extent. The : objective was to ascertain the ability of an expedient earth resistivity survey ...

  18. Terrestrial Permafrost as a Model Environment for Bioastronomy

    Science.gov (United States)

    Tsapin, A.; McDonald, G. D.

    2004-06-01

    The extent to which organisms can survive extended periods of metabolic inactivity in cold environments such as permafrost is one of the key questions in the study of life in extreme environments and for astrobiology. Viable bacteria have been cultured from million year-old Siberian permafrost samples, but the relationship between the age of the bacteria and the age of the sediments remains controversial. In this study we analyze the level of racemization of amino acids in permafrost samples collected from several sites in Northern Siberia. We have shown that even during long exposures to low temperatures (-10°C to -15°C), the bacterial cells in permafrost are not completely dormant, but continue to metabolize and at least partially control the extent of amino acid racemization.

  19. The application of refraction seismics in alpine permafrost studies

    Science.gov (United States)

    Draebing, Daniel

    2017-04-01

    Permafrost studies in alpine environments focus on landslides from permafrost-affected rockwalls, landslide deposits or periglacial sediment dynamics. Mechanical properties of soils or rocks are influenced by permafrost and changed strength properties affect these periglacial processes. To assess the effects of permafrost thaw and degradation, monitoring techniques for permafrost distribution and active-layer thaw are required. Seismic wave velocities are sensitive to freezing and, therefore, refraction seismics presents a valuable tool to investigate permafrost in alpine environments. In this study, (1) laboratory and field applications of refraction seismics in alpine environments are reviewed and (2) data are used to quantify effects of rock properties (e.g. lithology, porosity, anisotropy, saturation) on p-wave velocities. In the next step, (3) influence of environmental factors are evaluated and conclusions drawn on permafrost differentiation within alpine periglacial landforms. This study shows that p-wave velocity increase is susceptible to porosity which is pronounced in high-porosity rocks. In low-porosity rocks, p-wave velocity increase is controlled by anisotropy decrease due to ice pressure (Draebing and Krautblatter, 2012) which enables active-layer and permafrost differentiation at rockwall scale (Krautblatter and Draebing, 2014; Draebing et al., 2016). However, discontinuity distribution can result in high anisotropy effects on seismic velocities which can impede permafrost differentiation (Phillips et al., 2016). Due to production or deposition history, porosity can show large spatial differences in deposited landforms. Landforms with large boulders such as rock glaciers and moraines show highest p-wave velocity differences between active-layer and permafrost which facilitates differentiation (Draebing, 2016). Saturation with water is essential for the successful application of refraction seismics for permafrost detection and can be controlled at

  20. Modelling and simulating the transitory regimes in NPP using the MMS package programs

    International Nuclear Information System (INIS)

    Prisecaru, I.; Dupleac, Daniel; Constantinescu, Adrian Cornel

    2003-01-01

    This paper introduces a brief presentation of the preoccupation of modelling and simulating group at the Nuclear Power Plant Department of the Faculty of Power Plant Engineering in 'Politehnica' University of Bucharest in using the Modular Modeling System, MMS, package programs for the simulation of NPP transitory regimes. Nuclear power plants are large, non-linear systems with numerous interactions between its components. In the analysis of such complex systems, dynamic simulation is recognized as a powerful method of keeping track of the myriad of interactions. The MMS is a simulation tool that has built in models for plant components using a modular approach to dynamic simulation. The MMS software modules were developed to correspond to plant components that are familiar to power plant engineers. The interface specifications of the modules were defined so that the modules can be interconnected analogously to components in the actual plant. For some components, several modules of differing complexity are available. These alternative modules allow the user to choose the module appropriate to his application, i.e. a detailed model or a more economical model with less detail. The modular nature of the MMS allows the user to tailor the goal of his simulation to the complexity of the application and allows the user to develop independent subsystems that can be integrated into a larger simulation. The MMS module library contains modules for components for fossil and nuclear power plants. Each module is a mathematical model of a type of plant component formulated from first principles. The MMS uses a simulation language that provides features to simplify the development of simulations. Features important to the development of the MMS are the macro capability, automatic sorting of modeling equations, and integration algorithms. The macro capability is used to express the modeling equations for an MMS module. Since modules may be used more than once in the same simulation

  1. Zero Time of Transitory Nuclear Events Derived by Parent-Daughter Systems

    International Nuclear Information System (INIS)

    Nir-El, Y.

    2014-01-01

    The detection and identification of a nuclear event that results in the dissemination of radioactive products into the environment can be realized by dating the age of the event. In order to correct observed activities for the decay since the occurrence of the event, the age must be known to a high level of confidence. Previous papers. described the method to date the age of a nuclear event by measuring the activity of two fission products, which constitute the clock in this application. Within the proficiency test programme for radionuclide laboratories supporting the CTBT, a simulated gamma spectrum with the characteristics of an atmospheric test of a Chinese thermonuclear device, was used to determine the zero time by calculating the theoretical peak area ratio of 95Nb/95Zr. Their approach used only the main gamma lines at 766 and 757 keV and assigned the same detection efficiency to both these close lines. Their methodology of calculating the uncertainty of zero time is subject to comments because it takes the sum of two components (nuclide ratio and activity ratio as function of time) in quadrature. In another paper, the activity of 95Nb as a function of time was presented without any development or expression for the zero time. Analytical equations for zero time and the associated uncertainty calculations were derived in a recent paper using a measured activity ratio of two nuclides and illustrating the procedure by data from the Chinese test. The evaluation of the zero time uncertainty was performed by a very large set of very complicated analytical equations. The present paper aims at developing a procedure to determine the zero time and its uncertainty in a transitory nuclear event by treating a parent-daughter system of 3 nuclides, where one daughter feeds the other one, in addition to its direct feeding by the decay of the parent

  2. Coincident aboveground and belowground autonomous monitoring to quantify covariability in permafrost, soil, and vegetation properties in Arctic tundra

    Science.gov (United States)

    Dafflon, Baptiste; Oktem, Rusen; Peterson, John; Ulrich, Craig; Tran, Anh Phuong; Romanovsky, Vladimir; Hubbard, Susan S.

    2017-06-01

    Coincident monitoring of the spatiotemporal distribution of and interactions between land, soil, and permafrost properties is important for advancing our understanding of ecosystem dynamics. In this study, a novel monitoring strategy was developed to quantify complex Arctic ecosystem responses to the seasonal freeze-thaw-growing season conditions. The strategy exploited autonomous measurements obtained through electrical resistivity tomography to monitor soil properties, pole-mounted optical cameras to monitor vegetation dynamics, point probes to measure soil temperature, and periodic manual measurements of thaw layer thickness, snow thickness, and soil dielectric permittivity. The spatially and temporally dense monitoring data sets revealed several insights about tundra system behavior at a site located near Barrow, AK. In the active layer, the soil electrical conductivity (a proxy for soil water content) indicated an increasing positive correlation with the green chromatic coordinate (a proxy for vegetation vigor) over the growing season, with the strongest correlation (R = 0.89) near the typical peak of the growing season. Soil conductivity and green chromatic coordinate also showed significant positive correlations with thaw depth, which is influenced by soil and surface properties. In the permafrost, soil electrical conductivity revealed annual variations in solute concentration and unfrozen water content, even at temperatures well below 0°C in saline permafrost. These conditions may contribute to an acceleration of long-term thaw in Coastal permafrost regions. Demonstration of this first aboveground and belowground geophysical monitoring approach within an Arctic ecosystem illustrates its significant potential to remotely "visualize" permafrost, soil, and vegetation ecosystem codynamics in high resolution over field relevant scales.

  3. Quantifying uncertainties of permafrost carbon-climate feedbacks

    Science.gov (United States)

    Burke, Eleanor J.; Ekici, Altug; Huang, Ye; Chadburn, Sarah E.; Huntingford, Chris; Ciais, Philippe; Friedlingstein, Pierre; Peng, Shushi; Krinner, Gerhard

    2017-06-01

    The land surface models JULES (Joint UK Land Environment Simulator, two versions) and ORCHIDEE-MICT (Organizing Carbon and Hydrology in Dynamic Ecosystems), each with a revised representation of permafrost carbon, were coupled to the Integrated Model Of Global Effects of climatic aNomalies (IMOGEN) intermediate-complexity climate and ocean carbon uptake model. IMOGEN calculates atmospheric carbon dioxide (CO2) and local monthly surface climate for a given emission scenario with the land-atmosphere CO2 flux exchange from either JULES or ORCHIDEE-MICT. These simulations include feedbacks associated with permafrost carbon changes in a warming world. Both IMOGEN-JULES and IMOGEN-ORCHIDEE-MICT were forced by historical and three alternative future-CO2-emission scenarios. Those simulations were performed for different climate sensitivities and regional climate change patterns based on 22 different Earth system models (ESMs) used for CMIP3 (phase 3 of the Coupled Model Intercomparison Project), allowing us to explore climate uncertainties in the context of permafrost carbon-climate feedbacks. Three future emission scenarios consistent with three representative concentration pathways were used: RCP2.6, RCP4.5 and RCP8.5. Paired simulations with and without frozen carbon processes were required to quantify the impact of the permafrost carbon feedback on climate change. The additional warming from the permafrost carbon feedback is between 0.2 and 12 % of the change in the global mean temperature (ΔT) by the year 2100 and 0.5 and 17 % of ΔT by 2300, with these ranges reflecting differences in land surface models, climate models and emissions pathway. As a percentage of ΔT, the permafrost carbon feedback has a greater impact on the low-emissions scenario (RCP2.6) than on the higher-emissions scenarios, suggesting that permafrost carbon should be taken into account when evaluating scenarios of heavy mitigation and stabilization. Structural differences between the land

  4. Quantifying uncertainties of permafrost carbon–climate feedbacks

    Directory of Open Access Journals (Sweden)

    E. J. Burke

    2017-06-01

    Full Text Available The land surface models JULES (Joint UK Land Environment Simulator, two versions and ORCHIDEE-MICT (Organizing Carbon and Hydrology in Dynamic Ecosystems, each with a revised representation of permafrost carbon, were coupled to the Integrated Model Of Global Effects of climatic aNomalies (IMOGEN intermediate-complexity climate and ocean carbon uptake model. IMOGEN calculates atmospheric carbon dioxide (CO2 and local monthly surface climate for a given emission scenario with the land–atmosphere CO2 flux exchange from either JULES or ORCHIDEE-MICT. These simulations include feedbacks associated with permafrost carbon changes in a warming world. Both IMOGEN–JULES and IMOGEN–ORCHIDEE-MICT were forced by historical and three alternative future-CO2-emission scenarios. Those simulations were performed for different climate sensitivities and regional climate change patterns based on 22 different Earth system models (ESMs used for CMIP3 (phase 3 of the Coupled Model Intercomparison Project, allowing us to explore climate uncertainties in the context of permafrost carbon–climate feedbacks. Three future emission scenarios consistent with three representative concentration pathways were used: RCP2.6, RCP4.5 and RCP8.5. Paired simulations with and without frozen carbon processes were required to quantify the impact of the permafrost carbon feedback on climate change. The additional warming from the permafrost carbon feedback is between 0.2 and 12 % of the change in the global mean temperature (ΔT by the year 2100 and 0.5 and 17 % of ΔT by 2300, with these ranges reflecting differences in land surface models, climate models and emissions pathway. As a percentage of ΔT, the permafrost carbon feedback has a greater impact on the low-emissions scenario (RCP2.6 than on the higher-emissions scenarios, suggesting that permafrost carbon should be taken into account when evaluating scenarios of heavy mitigation and stabilization

  5. Snowball Earth termination by destabilization of equatorial permafrost methane clathrate.

    Science.gov (United States)

    Kennedy, Martin; Mrofka, David; von der Borch, Chris

    2008-05-29

    The start of the Ediacaran period is defined by one of the most severe climate change events recorded in Earth history--the recovery from the Marinoan 'snowball' ice age, approximately 635 Myr ago (ref. 1). Marinoan glacial-marine deposits occur at equatorial palaeolatitudes, and are sharply overlain by a thin interval of carbonate that preserves marine carbon and sulphur isotopic excursions of about -5 and +15 parts per thousand, respectively; these deposits are thought to record widespread oceanic carbonate precipitation during postglacial sea level rise. This abrupt transition records a climate system in profound disequilibrium and contrasts sharply with the cyclical stratigraphic signal imparted by the balanced feedbacks modulating Phanerozoic deglaciation. Hypotheses accounting for the abruptness of deglaciation include ice albedo feedback, deep-ocean out-gassing during post-glacial oceanic overturn or methane hydrate destabilization. Here we report the broadest range of oxygen isotope values yet measured in marine sediments (-25 per thousand to +12 per thousand) in methane seeps in Marinoan deglacial sediments underlying the cap carbonate. This range of values is likely to be the result of mixing between ice-sheet-derived meteoric waters and clathrate-derived fluids during the flushing and destabilization of a clathrate field by glacial meltwater. The equatorial palaeolatitude implies a highly volatile shelf permafrost pool that is an order of magnitude larger than that of the present day. A pool of this size could have provided a massive biogeochemical feedback capable of triggering deglaciation and accounting for the global postglacial marine carbon and sulphur isotopic excursions, abrupt unidirectional warming, cap carbonate deposition, and a marine oxygen crisis. Our findings suggest that methane released from low-latitude permafrost clathrates therefore acted as a trigger and/or strong positive feedback for deglaciation and warming. Methane hydrate

  6. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Richard Sigal; Kent Newsham; Thomas Williams; Barry Freifeld; Timothy Kneafsey; Carl Sondergeld; Shandra Rai; Jonathan Kwan; Stephen Kirby; Robert Kleinberg; Doug Griffin

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. The work scope drilled and cored a well The Hot Ice No. 1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report. The Hot Ice No. 1 well was drilled from the surface to a measured depth of 2300 ft. There was almost 100% core recovery from the bottom of surface casing at 107 ft to total depth. Based on the best estimate of the bottom of the methane hydrate stability zone (which used new data obtained from Hot Ice No. 1 and new analysis of data from adjacent wells), core was recovered over its complete range. Approximately 580 ft of porous, mostly frozen, sandstone and 155 of conglomerate were recovered in the Ugnu Formation and approximately 215 ft of porous sandstone were recovered in the West Sak Formation. There were gas shows in the bottom

  7. Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

    Science.gov (United States)

    Arp, Christopher D.; Whitman, Matthew S.; Jones, Benjamin M.; Grosse, Guido; Gaglioti, Benjamin V.; Heim, Kurt C.

    2015-01-01

    Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic survey of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high- ground ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate a relatively stable landform and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in riparian zones effectively insulates channel ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2°C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m/s, yet channel runs still move water rapidly

  8. Modelling rock wall permafrost degradation in the Mont Blanc massif from the LIA to the end of the 21st century

    Science.gov (United States)

    Magnin, Florence; Josnin, Jean-Yves; Ravanel, Ludovic; Pergaud, Julien; Pohl, Benjamin; Deline, Philip

    2017-08-01

    High alpine rock wall permafrost is extremely sensitive to climate change. Its degradation has a strong impact on landscape evolution and can trigger rockfalls constituting an increasing threat to socio-economical activities of highly frequented areas; quantitative understanding of permafrost evolution is crucial for such communities. This study investigates the long-term evolution of permafrost in three vertical cross sections of rock wall sites between 3160 and 4300 m above sea level in the Mont Blanc massif, from the Little Ice Age (LIA) steady-state conditions to 2100. Simulations are forced with air temperature time series, including two contrasted air temperature scenarios for the 21st century representing possible lower and upper boundaries of future climate change according to the most recent models and climate change scenarios. The 2-D finite element model accounts for heat conduction and latent heat transfers, and the outputs for the current period (2010-2015) are evaluated against borehole temperature measurements and an electrical resistivity transect: permafrost conditions are remarkably well represented. Over the past two decades, permafrost has disappeared on faces with a southerly aspect up to 3300 m a.s.l. and possibly higher. Warm permafrost (i.e. > - 2 °C) has extended up to 3300 and 3850 m a.s.l. in N and S-exposed faces respectively. During the 21st century, warm permafrost is likely to extend at least up to 4300 m a.s.l. on S-exposed rock walls and up to 3850 m a.s.l. depth on the N-exposed faces. In the most pessimistic case, permafrost will disappear on the S-exposed rock walls at a depth of up to 4300 m a.s.l., whereas warm permafrost will extend at a depth of the N faces up to 3850 m a.s.l., but possibly disappearing at such elevation under the influence of a close S face. The results are site specific and extrapolation to other sites is limited by the imbrication of local topographical and transient effects.

  9. River Export of Dissolved and Particulate Organic Carbon from Permafrost and Peat Deposits across the Siberian Arctic

    Science.gov (United States)

    Wild, B.; Andersson, A.; Bröder, L.; Vonk, J.; Hugelius, G.; McClelland, J. W.; Raymond, P. A.; Gustafsson, O.

    2017-12-01

    Permafrost and peat deposits of northern high latitudes store more than 1300 Pg of organic carbon. This carbon has been preserved for thousands of years by cold and moist conditions, but is now increasingly mobilized as temperatures rise. While part will be degraded to CO2 and CH4 and amplify global warming, part will be exported by rivers to the Arctic Ocean where it can be degraded or re-buried by sedimentation. We here use the four large Siberian rivers Ob, Yenisey, Lena, and Kolyma as natural integrators of carbon mobilization in their catchments. We apply isotope based source apportionments and Markov Chain Monte Carlo Simulations to quantify contributions of organic carbon from permafrost and peat deposits to organic carbon exported by these rivers. More specifically, we compare the 14C signatures of dissolved and particulate organic carbon (DOC, POC) sampled close to the river mouths with those of five potential carbon sources; (1) recent aquatic and (2) terrestrial primary production, (3) the active layer of permafrost soils, (4) deep Holocene deposits (including thermokarst and peat deposits) and (5) Ice Complex Deposits. 14C signatures of these endmembers were constrained based on extensive literature review. We estimate that the four rivers together exported 2.4-4.5 Tg organic carbon from permafrost and peat deposits per year. While total organic carbon export was dominated by DOC (90%), the export of organic carbon from permafrost and peat deposits was more equally distributed between DOC (56%) and POC (44%). Recent models predict that ca. 200 Pg carbon will be lost as CO2 or CH4 by 2100 (RCP8.5) from the circumarctic permafrost area, of which roughly a quarter is drained by the Ob, Yenisey, Lena, and Kolyma rivers. Our comparatively low estimates of river carbon export thus suggest limited transfer of organic carbon from permafrost and peat deposits to high latitude rivers, or its rapid degradation within rivers. Our findings highlight the importance

  10. Exploring Viral Mediated Carbon Cycling in Thawing Permafrost Microbial Communities

    Science.gov (United States)

    Trubl, G. G.; Solonenko, N.; Moreno, M.; Sullivan, M. B.; Rich, V. I.

    2014-12-01

    Viruses are the most abundant biological entities on Earth and their impact on carbon cycling in permafrost habitats is poorly understood. Arctic C cycling is particularly important to interpret due to the rapid climate change occurring and the large amount of C stockpiled there (~1/3 of global soil C is stored in permafrost). Viruses of microbes (i.e. phages) play central roles in C cycling in the oceans, through cellular lysis (phage drive the largest ocean C flux about 150 Gt yr-1, dwarfing all others by >5-fold), production of associated DOC, as well as transport and expression during infection (1029 transduction events day-1). C cycling in thawing permafrost systems is critical in understanding the climate trajectory and phages may be as important for C cycling here as they are in the ocean. The thawed C may become a food source for microbes, producing CO2 and potentially CH4, both potent greenhouse gases. To address the potential role of phage in C cycling in these dynamic systems, we are examining phage from an arctic permafrost thaw gradient in northern Sweden. We have developed a protocol for successfully extracting phage from peat soils and are quantifying phage in 15 peat and 2 lake sediment cores, with the goal of sequencing viromes. Preliminary data suggest that phage are present at 109 g-1 across the permafrost thaw gradient (compared to the typical marine count ~105 ml-1), implying a potentially robust phage-host interaction web in these changing environments. We are examining phage from 11 depth intervals (covering the active and permafrost layer) in the cores to assess phage-host community dynamics. Phage morphology and abundance for each layer and environment are being determined using qTEM and EFM. Understanding the phage that infect bacteria and archaea in these rapidly changing habitats will provide insight into the controls on current and future CH4 and CO2 emissions in permafrost habitats.

  11. Comparison of CO2 fluxes in a larch forest on permafrost and a pine forest on non-permafrost soils in Central Siberia

    Science.gov (United States)

    Zyryanov, V.; Tchebakova, N. M.; Nakai, Y.; Zyryanova, O.; Parfenova, E. I.; Matsuura, Y.; Vygodskaya, N.

    2013-12-01

    Inter-annual and seasonal variations of energy, water and carbon fluxes and associated climate variables in a middle taiga pine (Pinus sylvestris) forest on warm sandy soils and a northern taiga larch (Larix gmelini) forest on permafrost in Central Siberia were studied from eddy covariance measurements obtained during growing seasons of 1998-2000 and 2004-2008 (except 2006) respectively. Both naturally regenerated after fire forests grew in different environments and differed by their tree stand characteristics. The pure Gmelin larch stand was 105 yr old, stem density of living trees was about 5480 trees/ha, LAI was 0.6 m2/m2, biomass (dry weight) was 0.0044 kg/m2, with average diameter of the trees at breast height 7.1 cm and mean tree height 6.8 m. The pure Scots pine stand was 215 yr old, stand structure was relatively homogenous with a stem density of 468 living trees/ha, LAI was 1.5 m2/m2, biomass (dry weight) was 10.7 kg/m2, with average diameter of the trees at breast height 28 cm and mean tree height 23 m. The climatic and soil conditions of these ecosystems were very distinctive. The habitat of the larch forest was much colder and dryer than that of the pine forest: the growing season was 1 month shorter and growing-degree days 200°C less and winters were about one month longer and colder with January temperature -37°C versus -23°C; annual precipitation was 400 mm in the larch versus 650 mm in the pine forest and maximal snow pack was 40 cm vs 70 cm. The soils were Gelisols with permafrost table within the upper 1 m in the larch stand and Pergelic Cryochrept, alluvial sandy soil with no underlying permafrost. Average daily net ecosystem exchange (NEE) was significantly smaller in the larch ecosystem - (-3-6) μmol/m2s compared to that in the pine forest (-7-8) μmol/m2s, however daily maximal NEE was about the same. Seasonal NEE in the larch forest on continuous permafrost varied from -53 to -107 and in the pine forest on non-permafrost from -180 to

  12. Relict gas hydrates as possible reason of gas emission from shallow permafrost at the northern part of West Siberia

    Science.gov (United States)

    Chuvilin, Evgeny; Bukhanov, Boris; Tumskoy, Vladimir; Istomin, Vladimir; Tipenko, Gennady

    2017-04-01

    Intra-permafrost gas (mostly methane) is represent a serious geological hazards during exploration and development of oil and gas fields. Special danger is posed by large methane accumulations which usually confined to sandy and silty sand horizons and overlying in the frozen strata on the depth up to 200 meters. Such methane accumulations are widely spread in a number of gas fields in the northern part of Western Siberia. According to indirect indicators this accumulations can be relic gas hydrates, that formed earlier during favorable conditions for hydrate accumulation (1, 2). Until now, they could be preserved in the frozen sediments due to geological manifestation of the self-preservation effect of gas hydrates at temperatures below zero. These gas hydrate formations, which are lying above the gas hydrate stability zone today, are in a metastable state and are very sensitive to various anthropogenic impacts. During drilling and operation of production wells in the areas where the relic of gas hydrates can occur, there are active gas emission and gas explosion, that can lead to various technical complications up to the accident. Mathematical and experimental simulations were were conducted to evaluate the possibility of existence of relic gas hydrates in the northern part of West Siberia. The results of math simulations revealed stages of geological history when the gas hydrate stability zone began virtually from the ground surface and saturated in shallow permafrost horizons. Later permafrost is not completely thaw. Experimental simulations of porous gas hydrate dissociation in frozen soils and evaluation of self-preservation manifestation of gas hydrates at negative temperatures were carried out for identification conditions for relic gas hydrates existence in permafrost of northern part of West Siberia. Sandy and silty sand sediments were used in experimental investigations. These sediments are typical of most gas-seeping (above the gas hydrate stability

  13. Brief Communication : Future avenues for permafrost science from the perspective of early career researchers

    NARCIS (Netherlands)

    Fritz, M.; Deshpande, B. N.; Bouchard, F.; Högström, E.; Malenfant-Lepage, J.; Morgenstern, A.; Nieuwendam, A.; Oliva, M.; Paquette, M.; Rudy, A. C A; Siewert, M. B.; Sjöberg, Y.; Weege, S.

    2015-01-01

    Accelerating climate change and increased economic and environmental interests in permafrost-affected regions have resulted in an acute need for more directed permafrost research. In June 2014, 88 early career researchers convened to identify future priorities for permafrost research. This

  14. Soil CO2 production in upland tundra where permafrost is thawing

    Science.gov (United States)

    Hanna Lee; Edward A.G. Schuur; Jason G. Vogel

    2010-01-01

    Permafrost soils store nearly half of global soil carbon (C), and therefore permafrost thawing could lead to large amounts of greenhouse gas emissions via decomposition of soil organic matter. When ice-rich permafrost thaws, it creates a localized surface subsidence called thermokarst terrain, which changes the soil microenvironment. We used soil profile CO2...

  15. Fossil organic matter characteristics in permafrost deposits of the northeast Siberian Arctic

    Science.gov (United States)

    Lutz Schirrmeister; Guido Grosse; Sebastian Wetterich; Pier Paul Overduin; Jens Straub; Edward A.G. Schuur; Hans-Wolfgang. Hubberton

    2011-01-01

    Permafrost deposits constitute a large organic carbon pool highly vulnerable to degradation and potential carbon release due to global warming. Permafrost sections along coastal and river bank exposures in NE Siberia were studied for organic matter (OM) characteristics and ice content. OM stored in Quaternary permafrost grew, accumulated, froze, partly decomposed, and...

  16. Stream dissolved organic matter bioavailability and composition in watersheds underlain with discontinuous permafrost

    Science.gov (United States)

    Kelly L. Balcarczyk; Jeremy B. Jones; Rudolf Jaffe; Nagamitsu Maie

    2009-01-01

    We examined the impact of permafrost on dissolved organic matter (DOM) composition in Caribou-Poker Creeks Research Watershed (CPCRW), a watershed underlain with discontinuous permafrost, in interior Alaska. The stream draining the high permafrost watershed had higher DOC and dissolved organic nitrogen (DON) concentrations, higher DOCDON and greater specific...

  17. Variability in the sensitivity among model simulations of permafrost and carbon dynamics in the permafrost region between 1960 and 2009

    Science.gov (United States)

    McGuire, A. David; Koven, Charles; Lawrence, David M.; Clein, Joy S.; Xia, Jiangyang; Beer, Christian; Burke, Eleanor J.; Chen, Guangsheng; Chen, Xiaodong; Delire, Christine; Jafarov, Elchin; MacDougall, Andrew H.; Marchenko, Sergey S.; Nicolsky, Dmitry J.; Peng, Shushi; Rinke, Annette; Saito, Kazuyuki; Zhang, Wenxin; Alkama, Ramdane; Bohn, Theodore J.; Ciais, Philippe; Decharme, Bertrand; Ekici, Altug; Gouttevin, Isabelle; Hajima, Tomohiro; Hayes, Daniel J.; Ji, Duoying; Krinner, Gerhard; Lettenmaier, Dennis P.; Luo, Yiqi; Miller, Paul A.; Moore, John C.; Romanovsky, Vladimir; Schädel, Christina; Schaefer, Kevin; Schuur, Edward A.G.; Smith, Benjamin; Sueyoshi, Tetsuo; Zhuang, Qianlai

    2016-01-01

    A significant portion of the large amount of carbon (C) currently stored in soils of the permafrost region in the Northern Hemisphere has the potential to be emitted as the greenhouse gases CO2and CH4 under a warmer climate. In this study we evaluated the variability in the sensitivity of permafrost and C in recent decades among land surface model simulations over the permafrost region between 1960 and 2009. The 15 model simulations all predict a loss of near-surface permafrost (within 3 m) area over the region, but there are large differences in the magnitude of the simulated rates of loss among the models (0.2 to 58.8 × 103 km2 yr−1). Sensitivity simulations indicated that changes in air temperature largely explained changes in permafrost area, although interactions among changes in other environmental variables also played a role. All of the models indicate that both vegetation and soil C storage together have increased by 156 to 954 Tg C yr−1between 1960 and 2009 over the permafrost region even though model analyses indicate that warming alone would decrease soil C storage. Increases in gross primary production (GPP) largely explain the simulated increases in vegetation and soil C. The sensitivity of GPP to increases in atmospheric CO2 was the dominant cause of increases in GPP across the models, but comparison of simulated GPP trends across the 1982–2009 period with that of a global GPP data set indicates that all of the models overestimate the trend in GPP. Disturbance also appears to be an important factor affecting C storage, as models that consider disturbance had lower increases in C storage than models that did not consider disturbance. To improve the modeling of C in the permafrost region, there is the need for the modeling community to standardize structural representation of permafrost and carbon dynamics among models that are used to evaluate the permafrost C feedback and for the modeling and observational communities to

  18. IMPACT OF JUTE RETTING ON NATIVE FISH DIVERSITY AND AQUATIC HEALTH OF ROADSIDE TRANSITORY WATER BODIES: AN ASSESSMENT IN EASTERN INDIA

    Directory of Open Access Journals (Sweden)

    Dipankar Ghosh

    2015-09-01

    Full Text Available Roadside transitory water bodies being manmade depressions have a great ecological and socio-economic importance from years. The effects of agricultural runoffs, jute retting, macro-phytes infestations and inadequate rainfall in changed climate often degrade transitory water bodies’ environment while the biodiversity have impacted severely because of population pressure, over exploitation and indiscriminate use of fine meshed fishing gears as a whole. Physico-chemical and biological analysis with fish species composition, relative abundance, diversity indices like species richness, evenness and Shannon-Wiener index were carried out for pre-, during and post-jute retting season and for year mean as a whole to assess impact of jute retting on the roadside transitory water body’s environmental health and indigenous fish diversity at Sahebnagar village in Nadia District, India. All the physico-chemical parameters barring biochemical oxygen demand and water transparency remained more or less same or marginally got little changed during those three seasons. As much as 19 native fish species with varied relative abundances and dominances were identified. Jute retting impacted lower native fish diversity indices like Shannon-Wiener index values (1.94 to 2.68 clearly indicated poor to moderate pollution status of the transitory water body in that area during monsoon in particular and throughout the year in general. So we opined there should be some control over the intense jute retting in the road side transitory water bodies for sustainable management of these manmade resources.

  19. Petroleum contamination movement into permafrost in the high Arctic

    International Nuclear Information System (INIS)

    Biggar, K.W.

    1997-01-01

    The extent of petroleum hydrocarbon contamination that has penetrated the active layer into the permafrost at sites where spills have occurred in Canada's Arctic was discussed. There was evidence to suggest that hydrocarbon contamination may enter the permafrost layer through gravity drainage and cap suction through fissures in the frozen soil, and perhaps by diffusion through the unfrozen water of fine-grained soils. Core samples were taken in frozen silty clay to be sectioned and analyzed for total petroleum hydrocarbons, using ultrasonic solvent extraction and gas chromatography and mass spectrometry analysis. It was concluded that it is possible for petroleum contamination in permafrost to migrate by gravity drainage down soil fissures and then diffuse into surrounding soil. 2 figs

  20. Improving Permafrost Hydrology Prediction Through Data-Model Integration

    Science.gov (United States)

    Wilson, C. J.; Andresen, C. G.; Atchley, A. L.; Bolton, W. R.; Busey, R.; Coon, E.; Charsley-Groffman, L.

    2017-12-01

    The CMIP5 Earth System Models were unable to adequately predict the fate of the 16GT of permafrost carbon in a warming climate due to poor representation of Arctic ecosystem processes. The DOE Office of Science Next Generation Ecosystem Experiment, NGEE-Arctic project aims to reduce uncertainty in the Arctic carbon cycle and its impact on the Earth's climate system by improved representation of the coupled physical, chemical and biological processes that drive how much buried carbon will be converted to CO2 and CH4, how fast this will happen, which form will dominate, and the degree to which increased plant productivity will offset increased soil carbon emissions. These processes fundamentally depend on permafrost thaw rate and its influence on surface and subsurface hydrology through thermal erosion, land subsidence and changes to groundwater flow pathways as soil, bedrock and alluvial pore ice and massive ground ice melts. LANL and its NGEE colleagues are co-developing data and models to better understand controls on permafrost degradation and improve prediction of the evolution of permafrost and its impact on Arctic hydrology. The LANL Advanced Terrestrial Simulator was built using a state of the art HPC software framework to enable the first fully coupled 3-dimensional surface-subsurface thermal-hydrology and land surface deformation simulations to simulate the evolution of the physical Arctic environment. Here we show how field data including hydrology, snow, vegetation, geochemistry and soil properties, are informing the development and application of the ATS to improve understanding of controls on permafrost stability and permafrost hydrology. The ATS is being used to inform parameterizations of complex coupled physical, ecological and biogeochemical processes for implementation in the DOE ACME land model, to better predict the role of changing Arctic hydrology on the global climate system. LA-UR-17-26566.

  1. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2005-03-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Oil-field engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in Arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrates agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored the HOT ICE No. 1 on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was designed, constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. Unfortunately, no gas hydrates were encountered in this well; however, a wealth of information was generated

  2. Do Transit-Oriented Developments (TODs) and Established Urban Neighborhoods Have Similar Walking Levels in Hong Kong?

    Science.gov (United States)

    Xiao, Yang; Sarkar, Chinmoy; Zacharias, John

    2018-01-01

    A sharp drop in physical activity and skyrocketing obesity rate has accompanied rapid urbanization in China. The urban planning concept of transit-oriented development (TOD) has been widely advocated in China to promote physical activity, especially walking. Indeed, many design features thought to promote walking—e.g., mixed land use, densification, and well-connected street network—often characterize both TODs and established urban neighborhoods. Thus, it is often assumed that TODs have similar physical activity benefits as established urban neighborhoods. To verify this assumption, this study compared walking behaviors in established urban neighborhoods and transit-oriented new towns in Hong Kong. To address the limitation of self-selection bias, we conducted a study using Hong Kong citywide public housing scheme, which assigns residents to different housing estates by flat availability and family size rather than personal preference. The results show new town residents walked less for transportation purpose than urban residents. New town residents far from the transit station (800–1200 m) walked less for recreational purpose than TOD residents close to a rail transit station (urban residents. The observed disparity in walking behaviors challenges the common assumption that TOD and established urban neighborhoods have similar impact on walking behavior. The results suggest the necessity for more nuanced planning strategies, taking local-level factors into account to promote walking of TOD residents who live far from transit stations. PMID:29558379

  3. Do Transit-Oriented Developments (TODs) and Established Urban Neighborhoods Have Similar Walking Levels in Hong Kong?

    Science.gov (United States)

    Lu, Yi; Gou, Zhonghua; Xiao, Yang; Sarkar, Chinmoy; Zacharias, John

    2018-03-20

    A sharp drop in physical activity and skyrocketing obesity rate has accompanied rapid urbanization in China. The urban planning concept of transit-oriented development (TOD) has been widely advocated in China to promote physical activity, especially walking. Indeed, many design features thought to promote walking-e.g., mixed land use, densification, and well-connected street network-often characterize both TODs and established urban neighborhoods. Thus, it is often assumed that TODs have similar physical activity benefits as established urban neighborhoods. To verify this assumption, this study compared walking behaviors in established urban neighborhoods and transit-oriented new towns in Hong Kong. To address the limitation of self-selection bias, we conducted a study using Hong Kong citywide public housing scheme, which assigns residents to different housing estates by flat availability and family size rather than personal preference. The results show new town residents walked less for transportation purpose than urban residents. New town residents far from the transit station (800-1200 m) walked less for recreational purpose than TOD residents close to a rail transit station (transit stations.

  4. Do Transit-Oriented Developments (TODs and Established Urban Neighborhoods Have Similar Walking Levels in Hong Kong?

    Directory of Open Access Journals (Sweden)

    Yi Lu

    2018-03-01

    Full Text Available A sharp drop in physical activity and skyrocketing obesity rate has accompanied rapid urbanization in China. The urban planning concept of transit-oriented development (TOD has been widely advocated in China to promote physical activity, especially walking. Indeed, many design features thought to promote walking—e.g., mixed land use, densification, and well-connected street network—often characterize both TODs and established urban neighborhoods. Thus, it is often assumed that TODs have similar physical activity benefits as established urban neighborhoods. To verify this assumption, this study compared walking behaviors in established urban neighborhoods and transit-oriented new towns in Hong Kong. To address the limitation of self-selection bias, we conducted a study using Hong Kong citywide public housing scheme, which assigns residents to different housing estates by flat availability and family size rather than personal preference. The results show new town residents walked less for transportation purpose than urban residents. New town residents far from the transit station (800–1200 m walked less for recreational purpose than TOD residents close to a rail transit station (<400 m or urban residents. The observed disparity in walking behaviors challenges the common assumption that TOD and established urban neighborhoods have similar impact on walking behavior. The results suggest the necessity for more nuanced planning strategies, taking local-level factors into account to promote walking of TOD residents who live far from transit stations.

  5. Electromagnetic Method for Exogenetic Geodynamic Elements Mapping in Permafrost Environment

    Science.gov (United States)

    Gordeev, V. F.; Malyshkov, S. Y.; Polyvach, V. I.

    2017-04-01

    Taking into account the global warming, there is a pressing need to detect thermokarsts and to monitor permafrosts during the design and construction of industry infrastructure in Northern regions. The paper suggests a permafrost probing method based on the Earth’s natural pulsed electromagnetic field parameters recording. Authors describe the architecture and algorithms for the recording hardware. Examples of thermokarst detecting in poleward region are demonstrated. Pulsed electromagnetic fields intensity over thermokarst funnels is 30 times higher than the background levels. Authors substantiate the method’s eligibility to monitor geocryologial processes.

  6. Present Permafrost Thaw in Central Yakutia, North-East Siberia: Surficial Geology and Hydrology Evidence

    Science.gov (United States)

    Czerniawska, Jolanta; Chlachula, Jiri

    2017-04-01

    Current climate change in the high-latitudes of Eurasia is a generally accepted phenomenon characterized by increased annual temperature values and marked weather anomalies observed in the sub-polar and polar regions. In the northern and NE Siberia, this trend of the MAT rise, documented particularly over the last three decades, is believed to account for the territorial lowland as well as insular mountain frozen ground thaw that in turn has triggered ecosystem feedbacks on the local as well as regional scales. In the northern regions of Yakutia, this is principally witnessed by accelerated near-surface dynamics of seasonally activated de-freezing grounds and inter-linked geomorphic and hydrological actions affecting large-scale tundra landscape settings. In the southern and central taiga-forest areas with perennial alpine and continuous permafrost conditions, respectively, an increased depth of the seasonally melted top-soil layers has become evident accompanied by thermokarst lake expansion and ground surface collapsing. Some cryogenic depressions generated from small gullies over the past decades eloquently demonstrate the intensity and scales of the current permafrost degradation in the Siberian North. The fluvial discharge is most dynamic in late spring to mid-summer because of the cumulative effect of snow-melting because of a high solar radiation and short intervals of torrential rains. Yet, the climate-change-dependent and most active geomorphic agent is the accelerated permafrost thaw seen in landslides and tundra-forest cover decay due to a higher water table. Numerous preserved biotic fossiliferous records Pleistocene and early Holocene in age are being exposed in this process providing unique palaeoecology evidence at particular sites. These climate-generated processes have mostly highly negative effects to the natural habitats (migratory animal routes and riverine biota due to an earlier ice-melting) as well as the local settlement communities

  7. Review and synthesis: Changing permafrost in a warming world and feedbacks to the Earth System

    Science.gov (United States)

    Grosse, Guido; Goetz, Scott; McGuire, A. David; Romanovsky, Vladimir E.; Schuur, Edward A.G.

    2016-01-01

    The permafrost component of the cryosphere is changing dramatically, but the permafrost region is not well monitored and the consequences of change are not well understood. Changing permafrost interacts with ecosystems and climate on various spatial and temporal scales. The feedbacks resulting from these interactions range from local impacts on topography, hydrology, and biology to complex influences on global scale biogeochemical cycling. This review contributes to this focus issue by synthesizing its 28 multidisciplinary studies which provide field evidence, remote sensing observations, and modeling results on various scales. We synthesize study results from a diverse range of permafrost landscapes and ecosystems by reporting key observations and modeling outcomes for permafrost thaw dynamics, identifying feedbacks between permafrost and ecosystem processes, and highlighting biogeochemical feedbacks from permafrost thaw. We complete our synthesis by discussing the progress made, stressing remaining challenges and knowledge gaps, and providing an outlook on future needs and research opportunities in the study of permafrost–ecosystem–climate interactions.

  8. Vegetation Changes in the Permafrost Regions of the Qinghai-Tibetan Plateau from 1982-2012: Different Responses Related to Geographical Locations and Vegetation Types in High-Altitude Areas.

    Directory of Open Access Journals (Sweden)

    Zhiwei Wang

    Full Text Available The Qinghai-Tibetan Plateau (QTP contains the largest permafrost area in a high-altitude region in the world, and the unique hydrothermal environments of the active layers in this region have an important impact on vegetation growth. Geographical locations present different climatic conditions, and in combination with the permafrost environments, these conditions comprehensively affect the local vegetation activity. Therefore, the responses of vegetation to climate change in the permafrost region of the QTP may be varied differently by geographical location and vegetation condition. In this study, using the latest Global Inventory Modeling and Mapping Studies (GIMMS Normalized Difference Vegetation Index (NDVI product based on turning points (TPs, which were calculated using a piecewise linear model, 9 areas within the permafrost region of the QTP were selected to investigate the effect of geographical location and vegetation type on vegetation growth from 1982 to 2012. The following 4 vegetation types were observed in the 9 selected study areas: alpine swamp meadow, alpine meadow, alpine steppe and alpine desert. The research results show that, in these study areas, TPs mainly appeared in 2000 and 2001, and almost 55.1% and 35.0% of the TPs were located in 2000 and 2001. The global standardized precipitation evapotranspiration index (SPEI and 7 meteorological variables were selected to analyze their correlations with NDVI. We found that the main correlative variables to vegetation productivity in study areas from 1982 to 2012 were precipitation, surface downward long-wave radiation and temperature. Furthermore, NDVI changes exhibited by different vegetation types within the same study area followed similar trends. The results show that regional effects rather than vegetation type had a larger impact on changes in vegetation growth in the permafrost regions of the QTP, indicating that climatic factors had a larger impact in the permafrost

  9. LiDAR for monitoring mass movements in permafrost environments at the cirque Hinteres Langtal, Austria, between 2000 and 2008

    Directory of Open Access Journals (Sweden)

    M. Avian

    2009-07-01

    Full Text Available Permafrost areas receive more and more attention in terms of natural hazards in recent years due to ongoing global warming. Active rockglaciers are mixtures of debris and ice (of different origin in high-relief environments indicating permafrost conditions for a substantial period of time. Style and velocity of the downward movement of this debris-ice-mass is influenced by topoclimatic conditions. The rockglacier Hinteres Langtalkar is stage of extensive modifications in the last decade as a consequence of an extraordinary high surface movement. Terrestrial laserscanning (or LiDAR campaigns have been out once or twice per year since 2000 to monitor surface dynamics at the highly active front of the rockglacier. High resolution digital terrain models are the basis for annual and inter-annual analysis of surface elevation changes. Results show that the observed area shows predominantly positive surface elevation changes causing a consequent lifting of the surface over the entire period. Nevertheless a decreasing surface lifting of the observed area in the last three years leads to the assumption that the material transport from the upper part declines in the last years. Furthermore the rockglacier front is characterized by extensive mass wasting and partly disintegration of the rockglacier body. As indicated by the LiDAR results as well as from field evidence, this rockglacier front seems to represent a permafrost influenced landslide.

  10. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Ali Kadaster; Bill Liddell; Tommy Thompson; Thomas Williams; Michael Niedermayr

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project was a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope included drilling and coring a well (Hot Ice No. 1) on Anadarko leases beginning in FY 2003 and completed in 2004. During the first drilling season, operations were conducted at the site between January 28, 2003 to April 30, 2003. The well was spudded and drilled to a depth of 1403 ft. Due to the onset of warmer weather, work was then suspended for the season. Operations at the site were continued after the tundra was re-opened the following season. Between January 12, 2004 and March 19, 2004, the well was drilled and cored to a final depth of 2300 ft. An on-site core analysis laboratory was built and implemented for determining physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. Final efforts of the project are to correlate geology, geophysics, logs, and drilling and

  11. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Steve Runyon; Mike Globe; Kent Newsham; Robert Kleinberg; Doug Griffin

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project was a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope included drilling and coring a well (Hot Ice No. 1) on Anadarko leases beginning in FY 2003 and completed in 2004. During the first drilling season, operations were conducted at the site between January 28, 2003 to April 30, 2003. The well was spudded and drilled to a depth of 1403 ft. Due to the onset of warmer weather, work was then suspended for the season. Operations at the site were continued after the tundra was re-opened the following season. Between January 12, 2004 and March 19, 2004, the well was drilled and cored to a final depth of 2300 ft. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling

  12. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Donn McGuire; Steve Runyon; Richard Sigal; Bill Liddell; Thomas Williams; George Moridis

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. Hot Ice No. 1 was planned to test the Ugnu and West Sak sequences for gas hydrates and a concomitant free gas accumulation on Anadarko's 100% working interest acreage in section 30 of Township 9N, Range 8E of the Harrison Bay quadrangle of the North Slope of Alaska. The Ugnu and West Sak intervals are favorably positioned in the hydrate-stability zone over an area extending from Anadarko's acreage westward to the vicinity of the aforementioned gas-hydrate occurrences. This suggests that a large, north-to-south trending gas-hydrate accumulation may exist in that area. The presence of gas shows in the Ugnu and West Sak reservoirs in wells situated eastward and down dip of the Hot Ice location indicate that a free-gas accumulation may be trapped by gas hydrates. The Hot Ice No. 1 well was designed to core from the surface to the base of the West Sak interval using the

  13. Is the ancient permafrost bacteria able to keep DNA stable?

    Indian Academy of Sciences (India)

    repair for cell structures (Brouchkov and Williams 2002) or preserve those otherwise prone to collapse because of the duration of their existence. If so, their mutation rates must be extremely low. This explains genome homology between ancient permafrost bacteria and modern strains. A number of publications as well as ...

  14. Coupled thermo-geophysical inversion for permafrost monitoring

    DEFF Research Database (Denmark)

    Tomaskovicova, Sona

    effectively lowers the freezing point of the soil. Consequently, these sediments have strength properties similar to thawed ground in spite of ground temperatures well below 0 ◦C. In the view of increasing pressure on infrastructure development, better knowledge of such permafrost types, distribution, thermal...

  15. Is the ancient permafrost bacteria able to keep DNA stable?

    Indian Academy of Sciences (India)

    that the mechanism is unknown, bacteria from amber are reported to survive for 40 million years or longer (Greenblatt et al. 2004). Living (or at least viable) bacteria apparently occur deep in solid-frozen ground (permafrost) in the cold regions (Gilichinsky and Wagener 1995). We isolated and characterized bacterial strains ...

  16. Threshold loss of discontinuous permafrost and landscape evolution.

    Science.gov (United States)

    Chasmer, Laura; Hopkinson, Chris

    2017-07-01

    This study demonstrates linkages between the 1997/1998 El Niño/Southern Oscillation index and a threshold shift to increased permafrost loss within a southern Taiga Plains watershed, Northwest Territories, Canada. Three-dimensional contraction of permafrost plateaus and changes in vegetation structural characteristics are determined from multitemporal airborne Light Detection And Ranging (LiDAR) surveys in 2008, 2011 and 2015. Morphological changes in permafrost cover are compared with optical image analogues from 1970, 1977, 2000 and 2008 and time-series hydro-climate data. Results demonstrate that significant changes in air temperature, precipitation, runoff and a shortening of the snow-covered season by 35 days (1998-2014) and 50 days (1998 only) occurred after 1997. The albedo reduction associated with 35 and 50 days less snow cover leads to increases in shortwave energy receipt during the active thaw period of ~12% (3% annually) and ~16% (5% annually), respectively. From 2000 to 2015, sporadic permafrost loss accelerated from 0.19% (of total basin area) per year between 1970 and 2000 to 0.58% per year from 2000 to 2015, with a projected total loss of permafrost by ~2044. From ~1997 to 2011, we observe a corresponding shift to increased runoff ratio. However, observed increases in the proportion of snow precipitation and the volumetric contribution of permafrost loss to runoff post-1997 (0.6-6.4% per year) cannot fully explain this shift. This suggests increases in drainage efficiency and possible losses from long-term groundwater storage as a result of subtle terrain morphological and soil zone hydraulic conductivity changes. These hydrological changes appear coincident with high vegetation mortality at plateau margins combined with succession-related canopy growth in some bog and fen areas, which are presumed to be drying. Similar changes in runoff response were observed at adjacent Birch, Trout and Jean Marie River watersheds indicating that observations

  17. Regional permafrost distribution based on remote sensing data

    Science.gov (United States)

    Prantl, Hannah; Sailer, Rudolf; Stötter, Johann; Nagler, Thomas

    2017-04-01

    The detection of permafrost phenomena and its distribution in mountain environments as well as the monitoring of changes of permafrost with respect to climatic changes is important for alpine risk, infrastructure, natural hazards and climate change studies. It is assumed that in Iceland less than ten percent of the land surface is underlain by permafrost and that most of it may disappear under global warming in the 21st century. In particular regions these changes will cause sincere problems for the society in mountainous regions. But because of the complexity of permafrost detection, the knowledge about its distribution in Iceland is currently not very well evaluated and only based on small-scale observations. As permafrost is at most not directly observable, different indicators, e.g. rock glaciers and perennial snow patches, can be mapped to identify the distribution of permafrost. The study site is situated on the Tröllaskagi peninsula, in Northern Iceland. The peninsula is situated between Skagafjörður and Eyjafjörður and the highest summits reach an altitude of about 1400. For large-scale identification of perennial snow patches (PSP) over the Tröllaskagi peninsula remote sensing techniques are a practicable technique. In our study, we use optical satellite (Landsat-5/7/8 and Sentinel-2B) data in combination with aerial images to map and monitor the spatial distribution of perennial snow patches, indicating a low or negative ground temperature underneath. After an atmospheric correction of the satellite data, pan sharpening of the Landsat data and resampling the Sentinel-2B data, and Normalized Difference Snow Index (NDSI) calculations, the perennial snow patches are classified in i) mainly permafrost, ii) mainly wind and iii) mainly avalanche induced origin. For that purpose, topographic information such as slope angle, aspect and curvature are determined from a DEM of Tröllaskagi peninsula. In a first step a digital elevation model with a grid size

  18. Illuminating Geochemical Controls of Methane Oxidation Along a Gradient of Permafrost Thaw

    Science.gov (United States)

    Perryman, C. R.; Kashi, N.; McCalley, C. K.; Malhotra, A.; Giesler, R.; Varner, R.

    2017-12-01

    Increases in annual mean temperature in the subarctic have accelerated the thaw of organic-rich permafrost peatlands, exacerbating methane (CH4) production from microbial decomposition of peat deposits and subsequent CH4 emissions. Methanotrophic bacteria may oxidize/consume upwards of 90% of produced CH4 in some settings, pending substrate availability and environmental conditions. Redox chemistry may also control the rate of CH4 oxidation in thawing permafrost areas, particularly redox potential (Eh) and the availability of oxygen (O2) and other terminal electron receptors. We investigated potential CH4 oxidation rates across a permafrost thaw gradient in Stordalen Mire (68°21'N,18°49'E) near Abisko, Sweden. Methane oxidation rates for sites from thawing and collapsed palsa, semi-wet Sphagnum, and open-water sedge sites were determined through laboratory incubations. Peat cores were extracted from two depths at each site and incubated at in situ temperatures and CH4 concentrations. Headspace samples were collected over a 48-hour period and analyzed for CH4 concentration using flame ionization detection gas chromatography (GC-FID). Dissolved O2, Eh, and dissolved CH4 were measured in sites with porewater. Oxidation rates ranged from <0.1 to 19 μg of CH4 per gram of dry biomass per day. Eh remained positive (41.6 to 316.8 mV) with available dissolved O2 (0.3 - 5.2 mg/L) in all measurement locations down to 20cm, indicating in situ aerobic CH4 oxidation is viable across these environments. Potential CH4 oxidation rates increased with increasing dissolved CH4 concentration. Highest potential CH4 oxidation rates were found in open-water sedge sites. Eh and dissolved O2 were lowest at these sites, suggesting that methanotrophs with low-O2 demand may populate sedge areas. Furthermore, potential CH4 oxidation rates were higher at depth than at the surface in thawing palsa, suggesting CH4 oxidation may mitigate CH4 production triggered by warming in these actively

  19. New observations indicate the possible presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

    Science.gov (United States)

    Vieira, Gonçalo; Mora, Carla; Faleh, Ali

    2017-07-01

    Relict and present-day periglacial features have been reported in the literature for the upper reaches of the High Atlas mountains, which is the highest range in North Africa (Djebel Toubkal - 4167 m a.s.l.). A lobate feature in the Irhzer Ikhibi south at 3800 m a.s.l. has been previously interpreted as an active rock glacier, but no measurements of ground or air temperatures are known to exist for the area. In order to assess the possible presence of permafrost, we analyse data from June 2015 to June 2016 from two air temperature measurement sites at 2370 and 3210 m a.s.l. and from four ground surface temperature (GST) sites at 3220, 3815, 3980 and 4160 m a.s.l. to characterize conditions along an altitudinal gradient along the Oued Ihghyghaye valley to the summit of the Djebel Toubkal. GSTs were collected at 1 h intervals, and the presence of snow cover at the monitoring sites was validated using Landsat 8 and Sentinel-2 imagery. Two field visits allowed for logger installation and collection and for assessing the geomorphological features in the area. The results show that snow plays a major role on the thermal regime of the shallow ground, inducing important spatial variability. The lowest site at 3220 m had a thermal regime characterized by frequent freeze-thaw cycles during the cold season but with few days of snow. When snow settled, the ground surface remained isothermal at 0 °C , indicating the absence of permafrost. The highest sites at 3980 and 4160 m a.s.l. showed very frequent freeze-thaw cycles and a small influence of the snow cover on GST, reflecting the lack of snow accumulation due to the wind-exposed settings on a ridge and on the summit plateau. The site located at 3815 m in the Irhzer Ikhibi south valley had a cold, stable thermal regime with GST varying from -4.5 to -6 °C from December to March, under a continuous snow cover. The site's location in a concave setting favours wind-driven snow accumulation and lower incoming solar radiation due

  20. Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis

    Science.gov (United States)

    Harp, D. R.; Atchley, A. L.; Painter, S. L.; Coon, E. T.; Wilson, C. J.; Romanovsky, V. E.; Rowland, J. C.

    2016-02-01

    The effects of soil property uncertainties on permafrost thaw projections are studied using a three-phase subsurface thermal hydrology model and calibration-constrained uncertainty analysis. The null-space Monte Carlo method is used to identify soil hydrothermal parameter combinations that are consistent with borehole temperature measurements at the study site, the Barrow Environmental Observatory. Each parameter combination is then used in a forward projection of permafrost conditions for the 21st century (from calendar year 2006 to 2100) using atmospheric forcings from the Community Earth System Model (CESM) in the Representative Concentration Pathway (RCP) 8.5 greenhouse gas concentration trajectory. A 100-year projection allows for the evaluation of predictive uncertainty (due to soil property (parametric) uncertainty) and the inter-annual climate variability due to year to year differences in CESM climate forcings. After calibrating to measured borehole temperature data at this well-characterized site, soil property uncertainties are still significant and result in significant predictive uncertainties in projected active layer thickness and annual thaw depth-duration even with a specified future climate. Inter-annual climate variability in projected soil moisture content and Stefan number are small. A volume- and time-integrated Stefan number decreases significantly, indicating a shift in subsurface energy utilization in the future climate (latent heat of phase change becomes more important than heat conduction). Out of 10 soil parameters, ALT, annual thaw depth-duration, and Stefan number are highly dependent on mineral soil porosity, while annual mean liquid saturation of the active layer is highly dependent on the mineral soil residual saturation and moderately dependent on peat residual saturation. By comparing the ensemble statistics to the spread of projected permafrost metrics using different climate models, we quantify the relative magnitude of soil

  1. The impact of permafrost-associated microorganisms on hydrate formation kinetics

    Science.gov (United States)

    Luzi-Helbing, Manja; Liebner, Susanne; Spangenberg, Erik; Wagner, Dirk; Schicks, Judith M.

    2016-04-01

    The relationship between gas hydrates, microorganisms and the surrounding sediment is extremely complex: On the one hand, microorganisms producing methane provide the prerequisite for gas hydrate formation. As it is known most of the gas incorporated into natural gas hydrates originates from biogenic sources. On the other hand, as a result of microbial activity gas hydrates are surrounded by a great variety of organic compounds which are not incorporated into the hydrate structure but may influence the formation or degradation process. For gas hydrate samples from marine environments such as the Gulf of Mexico a direct association between microbes and gas hydrates was shown by Lanoil et al. 2001. It is further assumed that microorganisms living within the gas hydrate stability zone produce biosurfactants which were found to enhance the hydrate formation process significantly and act as nucleation centres (Roger et al. 2007). Another source of organic compounds is sediment organic matter (SOM) originating from plant material or animal remains which may also enhance hydrate growth. So far, the studies regarding this relationship were focused on a marine environment. The scope of this work is to extend the investigations to microbes originating from permafrost areas. To understand the influence of microbial activity in a permafrost environment on the methane hydrate formation process and the stability conditions of the resulting hydrate phase we will perform laboratory studies. Thereby, we mimic gas hydrate formation in the presence and absence of methanogenic archaea (e.g. Methanosarcina soligelidi) and other psychrophilic bacteria isolated from permafrost environments of the Arctic and Antarctic to investigate their impact on hydrate induction time and formation rates. Our results may contribute to understand and predict the occurrences and behaviour of potential gas hydrates within or adjacent to the permafrost. Lanoil BD, Sassen R, La Duc MT, Sweet ST, Nealson KH

  2. Landsat time series analysis documents beaver migration into permafrost landscapes of arctic Alaska

    Science.gov (United States)

    Jones, B. M.; Tape, K. D.; Nitze, I.; Arp, C. D.; Grosse, G.; Zimmerman, C. E.

    2017-12-01

    Landscape-scale impacts of climate change in the Arctic include increases in growing season length, shrubby vegetation, winter river discharge, snowfall, summer and winter water temperatures, and decreases in river and lake ice thickness. Combined, these changes may have created conditions that are suitable for beaver colonization of low Arctic tundra regions. We developed a semi-automated workflow that analyzes Landsat imagery time series to determine the extent to which beavers may have colonized permafrost landscapes in arctic Alaska since 1999. We tested this approach on the Lower Noatak, Wulik, and Kivalina river watersheds in northwest Alaska and identified 83 locations representing potential beaver activity. Seventy locations indicated wetting trends and 13 indicated drying trends. Verification of each site using high-resolution satellite imagery showed that 80 % of the wetting locations represented beaver activity (damming and pond formation), 11 % were unrelated to beavers, and 9 % could not readily be distinguished as being beaver related or not. For the drying locations, 31 % represented beaver activity (pond drying due to dam abandonment), 62 % were unrelated to beavers, and 7 % were undetermined. Comparison of the beaver activity database with historic aerial photography from ca. 1950 and ca. 1980 indicates that beavers have recently colonized or recolonized riparian corridors in northwest Alaska. Remote sensing time series observations associated with the migration of beavers in permafrost landscapes in arctic Alaska include thermokarst lake expansion and drainage, thaw slump initiation, ice wedge degradation, thermokarst shore fen development, and possibly development of lake and river taliks. Additionally, beaver colonization in the Arctic may alter channel courses, thermal regimes, hyporheic flow, riparian vegetation, and winter ice regimes that could impact ecosystem structure and function in this region. In particular, the combination of beaver

  3. Data analysis and mapping of the mountain permafrost distribution

    Science.gov (United States)

    Deluigi, Nicola; Lambiel, Christophe; Kanevski, Mikhail

    2017-04-01

    In Alpine environments mountain permafrost is defined as a thermal state of the ground and corresponds to any lithosphere material that is at or below 0°C for, at least, two years. Its degradation is potentially leading to an increasing rock fall activity, rock glacier accelerations and an increase in the sediment transfer rates. During the last 15 years, knowledge on this phenomenon has significantly increased thanks to many studies and monitoring projects. They revealed a spatial distribution extremely heterogeneous and complex. As a consequence, modelling the potential extent of the mountain permafrost recently became a very important task. Although existing statistical models generally offer a good overview at a regional scale, they are not always able to reproduce its strong spatial discontinuity at the micro scale. To overcome this lack, the objective of this study is to propose an alternative modelling approach using three classification algorithms belonging to statistics and machine learning: Logistic regression (LR), Support Vector Machines (SVM) and Random forests (RF). The former is a linear parametric classifier that commonly used as a benchmark classification algorithm to be employed before using more complex classifiers. Non-linear SVM is a non-parametric learning algorithm and it is a member of the so-called kernel methods. RF are an ensemble learning method based on bootstrap aggregating and offer an embedded measure of the variable importance. Permafrost evidences were selected in a 588 km2 area of the Western Swiss Alps and serve as training examples. They were mapped from field data (thermal and geoelectrical data) and ortho-image interpretation (rock glacier inventorying). The dataset was completed with environmental predictors such as altitude, mean annual air temperature, aspect, slope, potential incoming solar radiation, normalized difference vegetation index and planar, profile and combined terrain curvature indices. Aiming at predicting

  4. Permafrost carbon-climate feedbacks accelerate global warming.

    Science.gov (United States)

    Koven, Charles D; Ringeval, Bruno; Friedlingstein, Pierre; Ciais, Philippe; Cadule, Patricia; Khvorostyanov, Dmitry; Krinner, Gerhard; Tarnocai, Charles

    2011-09-06

    Permafrost soils contain enormous amounts of organic carbon, which could act as a positive feedback to global climate change due to enhanced respiration rates with warming. We have used a terrestrial ecosystem model that includes permafrost carbon dynamics, inhibition of respiration in frozen soil layers, vertical mixing of soil carbon from surface to permafrost layers, and CH(4) emissions from flooded areas, and which better matches new circumpolar inventories of soil carbon stocks, to explore the potential for carbon-climate feedbacks at high latitudes. Contrary to model results for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4), when permafrost processes are included, terrestrial ecosystems north of 60°N could shift from being a sink to a source of CO(2) by the end of the 21st century when forced by a Special Report on Emissions Scenarios (SRES) A2 climate change scenario. Between 1860 and 2100, the model response to combined CO(2) fertilization and climate change changes from a sink of 68 Pg to a 27 + -7 Pg sink to 4 + -18 Pg source, depending on the processes and parameter values used. The integrated change in carbon due to climate change shifts from near zero, which is within the range of previous model estimates, to a climate-induced loss of carbon by ecosystems in the range of 25 + -3 to 85 + -16 Pg C, depending on processes included in the model, with a best estimate of a 62 + -7 Pg C loss. Methane emissions from high-latitude regions are calculated to increase from 34 Tg CH(4)/y to 41-70 Tg CH(4)/y, with increases due to CO(2) fertilization, permafrost thaw, and warming-induced increased CH(4) flux densities partially offset by a reduction in wetland extent.

  5. Tracking permafrost soil degradation through sulphur biogeochemical tracers

    Science.gov (United States)

    Canario, João; Santos, Margarida C.; Vieira, Gonçalo; Vincent, Warwick F.

    2017-04-01

    Rising temperatures are contributing to the rapid degradation of Arctic permafrost soils. Several studies have been using some biogeochemical tracers as indicators of the organic matter degradation although fewer attention has been given to sulphur. In fact, the chemistry of this element is of environmental importance because it plays a key role in the degradation of natural organic matter and influences the partitioning, speciation and fate of other trace elements. To better understand the role of sulphur in biogeochemical processes in permafrost soils several campaigns were undertaken in the Canadian subarctic region of Kuujjuarapik-Whapmagoostui and Umiujaq (QC) as a part of the Canadian ADAPT and the Portuguese PERMACHEM projects. In four sites along those regions soil samples were collected and pore water were extracted. Dissolved sulphur compounds (sulphide and sulphate) were determined in water samples while in soils particulate sulphides, pyrite and elemental sulphur were quantified by voltammetry. Organic sulphur compounds were identified using 33SssNMR and X-ray diffraction both in powder and single crystal analysis were used to identify crystalline sulphides. Finally, subsamples of soils and water samples were analysed for total particulate and dissolved organic carbon. The results showed that sulphur composition depends largely on the origin of permafrost soils. In soils originated from organic-rich palsas, the proportion of organic sulphur (% of the total) is higher than 50%, while in mineral lithalsa soils the opposite was found. In both cases the origin of sulphur was mainly from plant organic matter degradation. The combined structural and chemical analysis allowed the identified different stages of soil degradation by determined the ratio between inorganic and organic sulphur species and by following the different NMR and XRD spectra. These preliminary results pointed to the importance of the sulphur biogeochemistry in permafrost soils and provide

  6. Determinanti strutturali e transitorie della mobilità del lavoro, " la congettura di Holt" e l'esperienza italiana

    Directory of Open Access Journals (Sweden)

    F. MODIGLIANI

    2014-03-01

    Full Text Available The work looks at Holt’s theoretical model of the labour market based on turnover rates and the case of Italy. The authors argue that Holt’s assumption that the flows of hirings and separations are random variables which remain constant as aggregate demand varies cannot be justified theoretically or empirically. “Holt’s conjecture” and the implications of its theoretical construction for the labour market and the Phillips curve are first examined. The authors then present a basic model and describe its implications for the structural and transitory determinants of labour mobility. An empirical test is then made with reference to the flows of hirings and separations in Italy are the results are presented.  Finally, the authors then discuss the implications of their model. JEL: J01, J60

  7. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  8. An observation-based constraint on permafrost loss as a function of global warming

    Science.gov (United States)

    Chadburn, S. E.; Burke, E. J.; Cox, P. M.; Friedlingstein, P.; Hugelius, G.; Westermann, S.

    2017-04-01

    Permafrost, which covers 15 million km2 of the land surface, is one of the components of the Earth system that is most sensitive to warming. Loss of permafrost would radically change high-latitude hydrology and biogeochemical cycling, and could therefore provide very significant feedbacks on climate change. The latest climate models all predict warming of high-latitude soils and thus thawing of permafrost under future climate change, but with widely varying magnitudes of permafrost thaw. Here we show that in each of the models, their present-day spatial distribution of permafrost and air temperature can be used to infer the sensitivity of permafrost to future global warming. Using the same approach for the observed permafrost distribution and air temperature, we estimate a sensitivity of permafrost area loss to global mean warming at stabilization of million km2 °C-1 (1σ confidence), which is around 20% higher than previous studies. Our method facilitates an assessment for COP21 climate change targets: if the climate is stabilized at 2 °C above pre-industrial levels, we estimate that the permafrost area would eventually be reduced by over 40%. Stabilizing at 1.5 °C rather than 2 °C would save approximately 2 million km2 of permafrost.

  9. Permafrost at its limits: The most easterly evidence of existing permafrost in the European Alps as indicated by ground temperature and geoelectrical measurements

    Science.gov (United States)

    Kellerer-Pirklbauer, A.; Kühnast, B.

    2009-04-01

    Mountain permafrost is a widespread phenomenon in alpine regions in the European Alps. For instance, some 2000 km² or 4% of the Austrian Alps are underlain by permafrost. Up to recent times most research on permafrost issues in Austria focused on the central and highest section of the Austrian Alps. By contrast, knowledge concerning marginal permafrost zones is fairly limited. To increase knowledge about the easternmost limit of permafrost in the European Alps, a research project focusing on the Seckauer Tauern Mountains (14°30'E to 15°00'E) and particularly on the Hochreichart area was initiated in 2004 by the first author. Since then, different methods have been applied such as e.g. geomorphic mapping, numerical permafrost modelling, multi-annual BTS measurements (since 2004) or continuous ground surface and near ground surface temperature measurements by miniature temperature data loggers/MTDs (since 2004). In order to verify the temperature data and to extend the spatial knowledge about permafrost distribution beyond point information, a geoelectrical survey was carried out at the end of August 2008 by applying the electrical resistivity tomography (ERT) method along a 120 m long profile covering the upper part of the rooting zone of a (more-or-less) relict rock glacier and the talus slope above. For this survey the two-dimensional (2D) electrical surveys was performed using the Wenner-Alfa configuration with 2.5 m spacing and an LGM-Lippmann 4-Punkt light hp resistivity-meter. The ERT results indicate an active layer of 2 to 4 m underlain by a permafrost body along 3/4 of the entire profile with resistivity values between 50 to 100 kOhm.m and extending to a depth of 10 to 15 m. The permafrost body is substantially thicker at the lower part of the profile (rock glacier; first 50 m of profile) compared to most of the upper part (talus slope). Focusing on the talus slope, the permafrost body is thickest on the central section of the profile (~5-6 m thickness

  10. Holocene ice-wedge polygon development in northern Yukon permafrost peatlands (Canada)

    Science.gov (United States)

    Fritz, Michael; Wolter, Juliane; Rudaya, Natalia; Palagushkina, Olga; Nazarova, Larisa; Obu, Jaroslav; Rethemeyer, Janet; Lantuit, Hugues; Wetterich, Sebastian

    2016-09-01

    Ice-wedge polygon (IWP) peatlands in the Arctic and Subarctic are extremely vulnerable to climatic and environmental change. We present the results of a multidisciplinary paleoenvironmental study on IWPs in the northern Yukon, Canada. High-resolution laboratory analyses were carried out on a permafrost core and the overlying seasonally thawed (active) layer, from an IWP located in a drained lake basin on Herschel Island. In relation to 14 Accelerator Mass Spectrometry (AMS) radiocarbon dates spanning the last 5000 years, we report sedimentary data including grain size distribution and biogeochemical parameters (organic carbon, nitrogen, C/N ratio, δ13C), stable water isotopes (δ18O, δD), as well as fossil pollen, plant macrofossil and diatom assemblages. Three sediment units (SUs) correspond to the main stages of deposition (1) in a thermokarst lake (SU1: 4950 to 3950 cal yrs BP), (2) during transition from lacustrine to palustrine conditions after lake drainage (SU2: 3950 to 3120 cal yrs BP), and (3) in palustrine conditions of the IWP field that developed after drainage (SU3: 3120 cal yrs BP to 2012 CE). The lacustrine phase (pre 3950 cal yrs BP) is characterized by planktonic-benthic and pioneer diatom species indicating circumneutral waters, and very few plant macrofossils. The pollen record has captured a regional signal of relatively stable vegetation composition and climate for the lacustrine stage of the record until 3950 cal yrs BP. Palustrine conditions with benthic and acidophilic diatom species characterize the peaty shallow-water environments of the low-centered IWP. The transition from lacustrine to palustrine conditions was accompanied by acidification and rapid revegetation of the lake bottom within about 100 years. Since the palustrine phase we consider the pollen record as a local vegetation proxy dominated by the plant communities growing in the IWP. Ice-wedge cracking in water-saturated sediments started immediately after lake drainage at

  11. Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw: example from Yukon Flats Basin, Alaska, United States

    Science.gov (United States)

    Walvoord, Michelle Ann; Voss, Clifford I.; Wellman, Tristan P.

    2012-01-01

    Understanding the role of permafrost in controlling groundwater flow paths and fluxes is central in studies aimed at assessing potential climate change impacts on vegetation, species habitat, biogeochemical cycling, and biodiversity. Recent field studies in interior Alaska show evidence of hydrologic changes hypothesized to result from permafrost degradation. This study assesses the hydrologic control exerted by permafrost, elucidates modes of regional groundwater flow for various spatial permafrost patterns, and evaluates potential hydrologic consequences of permafrost degradation. The Yukon Flats Basin (YFB), a large (118,340 km2) subbasin within the Yukon River Basin, provides the basis for this investigation. Model simulations that represent an assumed permafrost thaw sequence reveal the following trends with decreasing permafrost coverage: (1) increased groundwater discharge to rivers, consistent with historical trends in base flow observations in the Yukon River Basin, (2) potential for increased overall groundwater flux, (3) increased spatial extent of groundwater discharge in lowlands, and (4) decreased proportion of suprapermafrost (shallow) groundwater contribution to total base flow. These trends directly affect the chemical composition and residence time of riverine exports, the state of groundwater-influenced lakes and wetlands, seasonal river-ice thickness, and stream temperatures. Presently, the YFB is coarsely mapped as spanning the continuous-discontinuous permafrost transition that model analysis shows to be a critical threshold; thus, the YFB may be on the verge of major hydrologic change should the current permafrost extent decrease. This possibility underscores the need for improved characterization of permafrost and other hydrogeologic information in the region via geophysical techniques, remote sensing, and ground-based observations.

  12. Cold adaptive traits revealed by comparative genomic analysis of the eurypsychrophile Rhodococcus sp. JG3 isolated from high elevation McMurdo Dry Valley permafrost, Antarctica.

    Science.gov (United States)

    Goordial, Jacqueline; Raymond-Bouchard, Isabelle; Zolotarov, Yevgen; de Bethencourt, Luis; Ronholm, Jennifer; Shapiro, Nicole; Woyke, Tanja; Stromvik, Martina; Greer, Charles W; Bakermans, Corien; Whyte, Lyle

    2016-02-01

    The permafrost soils of the high elevation McMurdo Dry Valleys are the most cold, desiccating and oligotrophic on Earth. Rhodococcus sp. JG3 is one of very few bacterial isolates from Antarctic Dry Valley permafrost, and displays subzero growth down to -5°C. To understand how Rhodococcus sp. JG3 is able to survive extreme permafrost conditions and be metabolically active at subzero temperatures, we sequenced its genome and compared it to the genomes of 14 mesophilic rhodococci. Rhodococcus sp. JG3 possessed a higher copy number of genes for general stress response, UV protection and protection from cold shock, osmotic stress and oxidative stress. We characterized genome wide molecular adaptations to cold, and identified genes that had amino acid compositions favourable for increased flexibility and functionality at low temperatures. Rhodococcus sp. JG3 possesses multiple complimentary strategies which may enable its survival in some of the harshest permafrost on Earth. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Subsea Permafrost Mapped Across the U.S. Beaufort Sea Using Multichannel Seismic Data

    Science.gov (United States)

    Brothers, L.; Hart, P. E.; Ruppel, C. D.

    2011-12-01

    Circum-Arctic continental shelves at water depths less than ~100 m were subaerial permafrost prior to the onset of sea-level rise starting in the late Pleistocene. Rapid transgression and the resulting temperature increase at the sediment surface have led to thawing of the inundated permafrost, landward retreat of the leading edge of the permafrost, and dissociation of permafrost-associated gas hydrates. Past numerical modeling has shown that gas hydrate dissociation is particularly pronounced at the permafrost-to-no permafrost transition offshore. On the U.S. Beaufort margin, subsea permafrost has never been systematically mapped, and the best insights about permafrost and associated gas hydrate have been based on a limited number of offshore boreholes and numerical studies, with sometimes contrasting predictions of the permafrost's seaward extent. We bring together 5370 km of multichannel seismic (MCS) data acquired during various proprietary exploration industry and public domain government surveys between 1977 and 1992 to map a velocity anomaly diagnostic of submerged permafrost along 500 km of the US Beaufort coastline. These high-velocity (>~2.8 km/s) refractions (HVR), which are evident in prestack MCS shot records, reveal laterally continuous layers of shallow, ice-bonded, coarse-grained sediments beneath the inner continental shelf. The HVR occur in less than 5% of the tracklines, and calculated HVR depths range from 60 to 350 m below seafloor. The velocity anomaly is not observed seaward of the 20 m isobath, and is only found within 30 km of the current shoreline. These results can be used to: 1) create a map of the minimum distribution of remaining US Beaufort shelf subsea permafrost; 2) reconcile discrepancies between model-predicted and borehole-verified offshore permafrost distribution; and 3) constrain where to expect hydrate dissociation.

  14. Influences of Moisture Regimes and Functional Plant Types on Nutrient Cycling in Permafrost Regions

    Science.gov (United States)

    McCaully, R. E.; Arendt, C. A.; Newman, B. D.; Heikoop, J. M.; Wilson, C. J.; Sevanto, S.; Wales, N. A.; Wullschleger, S.

    2017-12-01

    In the permafrost-dominated Arctic, climatic feedbacks exist between permafrost, soil moisture, functional plant type and presence of nutrients. Functional plant types present within the Arctic regulate and respond to changes in hydrologic regimes and nutrient cycling. Specifically, alders are a member of the birch family that use root nodules to fix nitrogen, which is a limiting nutrient strongly linked to fertilizing Arctic ecosystems. Previous investigations in the Seward Peninsula, AK show elevated presence of nitrate within and downslope of alder patches in degraded permafrost systems, with concentrations an order of magnitude greater than that of nitrate measured above these patches. Further observations within these degraded permafrost systems are crucial to assess whether alders are drivers of, or merely respond to, nitrate fluxes. In addition to vegetative feedbacks with nitrate supply, previous studies have also linked low moisture content to high nitrate production. Within discontinuous permafrost regions, the absence of permafrost creates well-drained regions with unsaturated soils whereas the presence of permafrost limits vertical drainage of soil-pore water creating elevated soil moisture content, which likely corresponds to lower nitrate concentrations. We investigate these feedbacks further in the Seward Peninsula, AK, through research supported by the United States Department of Energy Next Generation Ecosystem Experiment (NGEE) - Arctic. Using soil moisture and thaw depth as proxies to determine the extent of permafrost degradation, we identify areas of discontinuous permafrost over a heterogeneous landscape and collect co-located soilwater chemistry samples to highlight the complex relationships that exist between alder patches, soil moisture regimes, the presence of permafrost and available nitrate supply. Understanding the role of nitrogen in degrading permafrost systems, in the context of both vegetation present and soil moisture, is crucial

  15. Modern Dynamics of Permafrost Temperature at the Northern Yakutia.

    Science.gov (United States)

    Kholodov, A.; Gilichinsky, D.; Shmelev, D.; Davydov, S.; Romanovsky, V.

    2012-04-01

    Northern Yakutia is characterized by a cold continental climate (mean annual air temperature is from -10.6 to -13.5°C). In terms of air temperature dynamics the period of the last 30 years can be divided into 2 stages: from 1980 to 1996-97 when the air temperature was relatively stable and from 1997 to the present time - the period of sustained warming. Permafrost is continuous here and has a thickness up to 700 m. It is the most ancient permafrost in the Northern hemisphere that had never been completely thawed during the Quaternary period. The network of geothermal observations includes 10 boreholes located in different natural zones within the region. 5 boreholes are situated in the tundra, 3 in the boreal forest and 1 within the Kolyma river flood plain. Mean annual ground temperature (MAGT) varies in the range from -12.3°C to -2.6°C depending on latitude and landscape. Comparison of modern observations and published data shows that the most significant changes in permafrost temperatures took place on the Kolyma Lowland. Permafrost temperature increased here by 1.5-2°C since 1980. Based on observation and published data analyses the following conclusions can be made. Modern mean annual ground temperature in this region varies in a wide range from -12.3° to -2.6°. Despite the absence of a latitudinal zonality in air temperature, the reduced warming influence of snow at the coastal sites in this region leads to a northward decrease in mean annual permafrost temperature (1°C by the 1o of latitude). It caused by the change of snow cover warming impact southward from the Arctic basin coast. From a rough estimate using the Kudryavtsev approach (Kudryavtsev, 1974) the warming influence of the snow is 0.5 to 1.5°C at the north-western part with a relatively maritime climate, while in the southern and eastern parts with more continental climate it is 3.5 to 4.5°C. Permafrost temperatures in this region did not change significantly from 1980 up to the end of the

  16. Towards a global harmonized permafrost soil organic carbon stock estimates.

    Science.gov (United States)

    Hugelius, G.; Mishra, U.; Yang, Y.

    2017-12-01

    Permafrost affected soils store disproportionately large amount of organic carbon stocks due to multiple cryopedogenic processes. Previous permafrost soil organic carbon (SOC) stock estimates used a variety of approaches and reported substantial uncertainty in SOC stocks of permafrost soils. Here, we used spatially referenced data of soil-forming factors (topographic attributes, land cover types, climate, and bedrock geology) and SOC pedon description data (n = 2552) in a regression kriging approach to predict the spatial and vertical heterogeneity of SOC stocks across the Northern Circumpolar and Tibetan permafrost regions. Our approach allowed us to take into account both environmental correlation and spatial autocorrelation to separately estimate SOC stocks and their spatial uncertainties (95% CI) for three depth intervals at 250 m spatial resolution. In Northern Circumpolar region, our results show 1278.1 (1009.33 - 1550.45) Pg C in 0-3 m depth interval, with 542.09 (451.83 - 610.15), 422.46 (306.48 - 550.82), and 313.55 (251.02 - 389.48) Pg C in 0 - 1, 1 - 2, and 2 - 3 m depth intervals, respectively. In Tibetan region, our results show 26.68 (9.82 - 79.92) Pg C in 0 - 3 m depth interval, with 13.98 (6.2 - 32.96), 6.49 (1.73 - 25.86), and 6.21 (1.889 - 20.90) Pg C in 0 - 1, 1 - 2, and 2 - 3 m depth intervals, respectively. Our estimates show large spatial variability (50 - 100% coefficient of variation, depending upon the study region and depth interval) and higher uncertainty range in comparison to existing estimates. We will present the observed controls of different environmental factors on SOC at the AGU meeting.

  17. Impacts of Permafrost on Infrastructure and Ecosystem Services

    Science.gov (United States)

    Trochim, E.; Schuur, E.; Schaedel, C.; Kelly, B. P.

    2017-12-01

    The Study of Environmental Arctic Change (SEARCH) program developed knowledge pyramids as a tool for advancing scientific understanding and making this information accessible for decision makers. Knowledge pyramids are being used to synthesize, curate and disseminate knowledge of changing land ice, sea ice, and permafrost in the Arctic. Each pyramid consists of a one-two page summary brief in broadly accessible language and literature organized by levels of detail including synthesizes and scientific building blocks. Three knowledge pyramids have been produced related to permafrost on carbon, infrastructure, and ecosystem services. Each brief answers key questions with high societal relevance framed in policy-relevant terms. The knowledge pyramids concerning infrastructure and ecosystem services were developed in collaboration with researchers specializing in the specific topic areas in order to identify the most pertinent issues and accurately communicate information for integration into policy and planning. For infrastructure, the main issue was the need to build consensus in the engineering and science communities for developing improved methods for incorporating data applicable to building infrastructure on permafrost. In ecosystem services, permafrost provides critical landscape properties which affect basic human needs including fuel and drinking water availability, access to hunting and harvest, and fish and wildlife habitat. Translating these broad and complex topics necessitated a systematic and iterative approach to identifying key issues and relating them succinctly to the best state of the art research. The development of the knowledge pyramids provoked collaboration and synthesis across distinct research and engineering communities. The knowledge pyramids also provide a solid basis for policy development and the format allows the content to be regularly updated as the research community advances.

  18. Priming-induced Changes in Permafrost Soil Organic Matter Decomposition

    Science.gov (United States)

    Pegoraro, E.; Schuur, E.; Bracho, R. G.

    2015-12-01

    Warming of tundra ecosystems due to climate change is predicted to thaw permafrost and increase plant biomass and litter input to soil. Additional input of easily decomposable carbon can alter microbial activity by providing a much needed energy source, thereby accelerating soil organic matter decomposition. This phenomenon, known as the priming effect, can increase CO2 flux from soil to the atmosphere. However, the extent to which this mechanism can decrease soil carbon stocks in the Arctic is unknown. This project assessed priming effects on permafrost soil collected from a moist acidic tundra site in Healy, Alaska. We hypothesized that priming would increase microbial activity by providing microbes with a fresh source of carbon, thereby increasing decomposition of old and slowly decomposing carbon. Soil from surface and deep layers were amended with multiple pulses of uniformly 13C labeled glucose and cellulose, and samples were incubated at 15° C to quantify whether labile substrate addition increased carbon mineralization. We quantified the proportion of old carbon mineralization by measuring 14CO2. Data shows that substrate addition resulted in higher respiration rates in amended soils; however, priming was only observed in deep layers, where 30% more soil-derived carbon was respired compared to control samples. This suggests that microbes in deep layers are limited in energy, and the addition of labile carbon increases native soil organic matter decomposition, especially in soil with greater fractions of slowly decomposing carbon. Priming in permafrost could exacerbate the effects of climate change by increasing mineralization rates of carbon accumulated over the long-term in deep layers. Therefore, quantifying priming effect in permafrost soils is imperative to understanding the dynamics of carbon turnover in a warmer world.

  19. IPA-IPY Thermal State of Permafrost (TSP) Snapshot Borehole Inventory, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — During the planning and implementation of the International Polar Year (IPY) 2007 - 2009, the International Permafrost Association (IPA) coordinated the acquisition...

  20. Examining Environmental Gradients with Remotely Sensed Data - the ESA GlobPermafrost project

    Science.gov (United States)

    Bartsch, Annett; Grosse, Guido; Kääb, Andreas; Westermann, Sebastian; Strozzi, Tazio; Wiesmann, Andreas; Duguay, Claude; Seifert, Frank Martin; Obu, Jaroslav; Nitze, Ingmar; Heim, Birgit; Haas, Antoni; Widhalm, Barbara

    2017-04-01

    Permafrost cannot be directly detected from space, but many surface features of permafrost terrains and typical periglacial landforms are observable with a variety of EO sensors ranging from very high to medium resolution at various wavelengths. In addition, landscape dynamics associated with permafrost changes and geophysical variables relevant for characterizing the state of permafrost, such as land surface temperature or freeze-thaw state can be observed with space-based Earth Observation. Suitable regions to examine environmental gradients across the Arctic have been defined in a community white paper (Bartsch et al. 2014). These transects have been updated within the ESA DUE GlobPermafrost project. The ESA DUE GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. Prototype product cases will cover different aspects of permafrost by integrating in situ measurements of subsurface properties and surface properties, Earth Observation, and modelling to provide a better understanding of permafrost today. The project will extend local process and permafrost monitoring to broader spatial domains, support permafrost distribution modelling, and help to implement permafrost landscape and feature mapping in a GIS framework. It will also complement active layer and thermal observing networks. Both lowland (latitudinal) and mountain (altitudinal) permafrost issues are addressed. The selected transects and first results will be presented. This includes identified needs from the user requirements survey, a review of existing land surface products available for the Arctic as well as prototypes of GlobPermafrost datasets, and the permafrost information system through which they can be accessed. Bartsch, Annett; Allard, Michel; Biskaborn, Boris Kolumban; Burba, George; Christiansen, Hanne H; Duguay

  1. Characteristics of ground motion at permafrost sites along the Qinghai-Tibet railway

    Science.gov (United States)

    Wang, L.; Wu, Z.; Sun, Jielun; Liu, Xiuying; Wang, Z.

    2009-01-01

    Based on 14 typical drilling holes distributed in the permafrost areas along the Qinghai-Tibet railway, the distribution of wave velocities of soils in the permafrost regions were determined. Using results of dynamic triaxial tests, the results of dynamic triaxiality test and time histories of ground motion acceleration in this area, characteristics of ground motion response were analyzed for these permafrost sites for time histories of ground accelerations with three exceedance probabilities (63%, 10% and 2%). The influence of ground temperature on the seismic displacement, velocity, acceleration and response spectrum on the surface of permafrost were also studied. ?? 2008 Elsevier Ltd. All rights reserved.

  2. Metagenomic analysis of permafrost microbial community response to thaw

    Energy Technology Data Exchange (ETDEWEB)

    Mackelprang, R.; Waldrop, M.P.; DeAngelis, K.M.; David, M.M.; Chavarria, K.L.; Blazewicz, S.J.; Rubin, E.M.; Jansson, J.K.

    2011-07-01

    We employed deep metagenomic sequencing to determine the impact of thaw on microbial phylogenetic and functional genes and related this data to measurements of methane emissions. Metagenomics, the direct sequencing of DNA from the environment, allows for the examination of whole biochemical pathways and associated processes, as opposed to individual pieces of the metabolic puzzle. Our metagenome analyses revealed that during transition from a frozen to a thawed state there were rapid shifts in many microbial, phylogenetic and functional gene abundances and pathways. After one week of incubation at 5°C, permafrost metagenomes converged to be more similar to each other than while they were frozen. We found that multiple genes involved in cycling of C and nitrogen shifted rapidly during thaw. We also constructed the first draft genome from a complex soil metagenome, which corresponded to a novel methanogen. Methane previously accumulated in permafrost was released during thaw and subsequently consumed by methanotrophic bacteria. Together these data point towards the importance of rapid cycling of methane and nitrogen in thawing permafrost.

  3. Increasing risks related to landslides from degrading permafrost into new lakes in de-glaciating mountain ranges

    Science.gov (United States)

    Haeberli, Wilfried; Schaub, Yvonne; Huggel, Christian

    2017-09-01

    While glacier volumes in most cold mountain ranges rapidly decrease due to continued global warming, degradation of permafrost at altitudes above and below glaciers is much slower. As a consequence, many still existing glacier and permafrost landscapes probably transform within decades into new landscapes of bare bedrock, loose debris, sparse vegetation, numerous new lakes and steep slopes with slowly degrading permafrost. These new landscapes are likely to persist for centuries if not millennia to come. During variable but mostly extended future time periods, such new landscapes will be characterized by pronounced disequilibria within their geo- and ecosystems. This especially involves long-term stability reduction of steep/icy mountain slopes as a slow and delayed reaction to stress redistribution following de-buttressing by vanishing glaciers and to changes in mechanical strength and hydraulic permeability caused by permafrost degradation. Thereby, the probability of far-reaching flood waves from large mass movements into lakes systematically increases with the formation of many new lakes and systems of lakes in close neighborhood to, or even directly at the foot of, so-affected slopes. Results of recent studies in the Swiss Alps are reviewed and complemented with examples from the Cordillera Blanca in Peru and the Mount Everest region in Nepal. Hot spots of future hazards from potential flood waves caused by large rock falls into new lakes can already now be recognized. To this end, integrated spatial information on glacier/permafrost evolution and lake formation can be used together with scenario-based models for rapid mass movements, impact waves and flood propagation. The resulting information must then be combined with exposure and vulnerability considerations related to settlements and infrastructure. This enables timely planning of risk reduction options. Such risk reduction options consist of two components: Mitigation of hazards, which in the present

  4. Identifying active methane-oxidizers in thawed Arctic permafrost by proteomics

    Science.gov (United States)

    Lau, C. M.; Stackhouse, B. T.; Chourey, K.; Hettich, R. L.; Vishnivetskaya, T. A.; Pfiffner, S. M.; Layton, A. C.; Mykytczuk, N. C.; Whyte, L.; Onstott, T. C.

    2012-12-01

    The rate of CH4 release from thawing permafrost in the Arctic has been regarded as one of the determining factors on future global climate. It is uncertain how indigenous microorganisms would interact with such changing environmental conditions and hence their impact on the fate of carbon compounds that are sequestered in the cryosol. Multitudinous studies of pristine surface cryosol (top 5 cm) and microcosm experiments have provided growing evidence of effective methanotrophy. Cryosol samples corresponding to active layer were sampled from a sparsely vegetated, ice-wedge polygon at the McGill Arctic Research Station at Axel Heiberg Island, Nunavut, Canada (N79°24, W90°45) before the onset of annual thaw. Pyrosequencing of 16S rRNA gene indicated the occurrence of methanotroph-containing bacterial families as minor components (~5%) in pristine cryosol including Bradyrhizobiaceae, Methylobacteriaceae and Methylocystaceae within alpha-Proteobacteria, and Methylacidiphilaceae within Verrucomicrobia. The potential of methanotrophy is supported by preliminary analysis of metagenome data, which indicated putative methane monooxygenase gene sequences relating to Bradyrhizobium sp. and Pseudonocardia sp. are present. Proteome profiling in general yielded minute traces of proteins, which likely hints at dormant nature of the soil microbial consortia. The lack of specific protein database for permafrost posted additional challenge to protein identification. Only 35 proteins could be identified in the pristine cryosol and of which 60% belonged to Shewanella sp. Most of the identified proteins are known to be involved in energy metabolism or post-translational modification of proteins. Microcosms amended with sodium acetate exhibited a net methane consumption of ~65 ngC-CH4 per gram (fresh weight) of soil over 16 days of aerobic incubation at room temperature. The pH in microcosm materials remained acidic (decreased from initial 4.7 to 4.5). Protein extraction and

  5. City branding : An effective assertion of identity or a transitory marketing trick?

    NARCIS (Netherlands)

    Kavaratzis, M; Ashworth, GJ

    2005-01-01

    Cities throughout Europe are increasingly importing the concept and techniques of product branding for use within place marketing, in pursuit of wider urban management goals, especially within the new conditions created by European integration. However, there is as yet little consensus about the

  6. Vulnerability of permafrost carbon to global warming. Part II: sensitivity of permafrost carbon stock to global warming

    Energy Technology Data Exchange (ETDEWEB)

    Khvorostyanov, D.V.; Ciais, G. (Laboratoire des Sciences du Climat et l' Environnement, Saclay (France)); Krinner, G. (Laboratoire de Glaciologie et Geophysique de l' Environnement, St Martin d' Heres (France)). e-mail: Dimitry.Khvorostiyanov@lsce.ipsl.fr; Zimov, S.A. (Northeast Science Station, Cherskii (RU)); Corradi, C. (UNITUS, Univ. of Tuscia, Veterbo (Italy)); Guggenberger, G. (Inst. of Soil Science and Plant Nutrition, Martin-Luther-Univ., Halle-Wittenberg (DE))

    2008-07-01

    In the companion paper (Part I), we presented a model of permafrost carbon cycle to study the sensitivity of frozen carbon stocks to future climate warming. The mobilization of deep carbon stock of the frozen Pleistocene soil in the case of rapid stepwise increase of atmospheric temperature was considered. In this work, we adapted the model to be used also for floodplain tundra sites and to account for the processes in the soil active layer. The new processes taken into account are litter input and decomposition, plant-mediated transport of methane, and leaching of exudates from plant roots. The SRES-A2 transient climate warming scenario of the IPSL CM4 climate model is used to study the carbon fluxes from the carbon-rich Pleistocene soil with seasonal active-layer carbon cycling on top of it. For a point to the southwest from the western branch of Yedoma Ice Complex, where the climate warming is strong enough to trigger self-sustainable decomposition processes, about 256 kg C/m2, or 70% of the initial soil carbon stock under present-day climate conditions, are emitted to the atmosphere in about 120 yr, including 20 kg C/m2 released as methane. The total average flux of CO{sub 2} and methane emissions to the atmosphere during this time is of 2.1 kg C/m2/yr. Within the Yedoma, whose most part of the territory remains relatively cold, the emissions are much smaller: 0.2 kg C/m2/yr between 2050 and 2100 for Yakutsk area. In a test case with saturated upper-soil meter, when the runoff is insufficient to evacuate the meltwater, 0.05 kg CH{sub 4}/m2/yr on average are emitted as methane during 250 yr starting from 2050. The latter can translate to the upper bound of 1 GtC/yr in CO{sub 2} equivalent from the 1 million km2 area of the Yedoma

  7. Historical and Possible Future Changes in Permafrost and Active Layer Thickness in Alaska: Implications to Landscape Changes and Permafrost Carbon Pool.

    Science.gov (United States)

    Marchenko, S. S.; Helene, G.; Euskirchen, E. S.; Breen, A. L.; McGuire, D.; Rupp, S. T.; Romanovsky, V. E.; Walsh, J. E.

    2017-12-01

    The Soil Temperature and Active Layer Thickness (ALT) Gridded Data was developed to quantify the nature and rate of permafrost degradation and its impact on ecosystems, infrastructure, CO2 and CH4 fluxes and net C storage following permafrost thaw across Alaska. To develop this database, we used the process-based permafrost dynamics model GIPL2 developed in the Geophysical Institute Permafrost Lab, UAF and which is the permafrost module of the Integrated Ecosystem Model (IEM) for Alaska and Northwest Canada. The climate forcing data for simulations were developed by the Scenarios Network for Alaska and Arctic Planning (SNAP, http://www.snap.uaf.edu/). These data are based on the historical CRU3.1 data set for the retrospective analysis period (1901-2009) and the five model averaged data were derived from the five CMIP5/AR5 IPCC Global Circulation Models that performed the best in Alaska and other northern regions: NCAR-CCSM4, GFDL-CM3, GISS-E2-R, IPSL-CM5A-LR, MRI-CGCM3. A composite of all five-model outputs for the RCP4.5 and RCP8.5 were used in these particular permafrost dynamics simulations. Data sets were downscaled to a 771 m resolution, using the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climatology. Additional input data (snow characteristics, soil thermal properties, soil water content, organic matter accumulation or its loss due to fire, etc.) came from the Terrestrial Ecosystem Model (TEM) and the ALFRESCO (ALaska FRame-based EcoSystem COde) model simulations. We estimated the dynamics of permafrost temperature, active layer thickness, area occupied by permafrost, and volume of seasonally thawed soils within the 4.75 upper meters (original TEM soil column) across the Alaska domain. Simulations of future changes in permafrost indicate that, by the end of the 21st century, late-Holocene permafrost in Alaska will be actively thawing at all locations and that some Late Pleistocene carbon-rich peatlands underlain by permafrost will

  8. Mapping of permafrost surface and active layer properties using GPR: a comparison of frequency dependencies

    DEFF Research Database (Denmark)

    Gacitua, Guisella; Uribe, José Andrés; Tamstorf, Mikkel Peter

    2011-01-01

    Ground penetrating radar (GPR) was used to detect internal features and conditions in the active layer of Zackenberg valley in North-East Greenland. For about 16 years there has been a monitoring programme that registers the physical and biological processes in the ecosystem.We aim to improve...... the monitoring accuracy of the active layer development and estimated soil water content. We used two different GPR frequencies to study their performance in High-Arctic cryoturbated soils. Here we present the analysis of the signal received by quantifying the power of the signal that is reflected from the top...... are suitable to measure thickness and to detect features in the active layer, the 400 MHz gives a better impression of the influence of the dielectric contrast effect from top of the permafrost zone which can be used to quantify the soil water content....

  9. The thin brown line: The crucial role of peat in protecting permafrost in Arctic Alaska

    Science.gov (United States)

    Gaglioti, B.; Mann, D. H.; Farquharson, L. M.; Baughman, C. A.; Jones, B. M.; Romanovsky, V. E.; Williams, A. P.; Andreu-Hayles, L.

    2017-12-01

    Ongoing warming threatens to thaw Arctic permafrost and release its stored carbon, which could trigger a permafrost-carbon feedback capable of augmenting global warming. The effects of warming air temperatures on permafrost are complicated by the fact that across much of the Arctic and Subarctic a mat of living plants and decaying litter cover the ground and buffer underlying permafrost from air temperatures. For simplicity here, we refer to this organic mat as "peat". Because this peat modifies heat flow between ground and air, the rate and magnitude of permafrost responses to changing climate - and hence the permafrost-carbon feedback - are partly slaved to the peat layer's slower dynamics. To explore this relationship, we used 14C-age offsets within lake sediments in Alaskan watersheds underlain by yedoma deposits to track the changing responses of permafrost thaw to fluctuating climate as peat accumulated over the last 14,000 years. As the peat layer built up, warming events became less effective at thawing permafrost and releasing ancient carbon. Consistent with this age-offset record, the geological record shows that early in post-glacial times when the peat cover was still thin and limited in extent, warm intervals triggered extensive thermokarst that resulted in rapid aggradation of floodplains. Today in contrast, hillslopes and floodplains remain stable despite rapid warming, probably because of the buffering effects of the extensive peat cover. Another natural experiment is provided by tundra fires like the 2007 Anaktuvuk River fire that removed the peat cover from tundra underlain by continuous permafrost and resulted in widespread thermkarsting. Further support for peat's critical role in protecting permafrost comes from the results of modeling how permafrost temperatures under different peat thicknesses respond to warming air temperature. Although post-industrial warming has not yet surpassed the buffering capacity of 14,000 years of peat buildup in

  10. Survey of Permafrost Thaw Influence on Surface Water Dissolved Organic Matter in Sub-Arctic Alaska

    Science.gov (United States)

    Gagne, K.; Walter Anthony, K. M.; Guerard, J.

    2016-12-01

    The chemical and functional group composition of permafrost organic matter largely remains unknown. Characterizing dissolved organic matter (DOM) chemical composition offers insight into the quality and extent of the permafrost carbon pool that may mobilize and transform into smaller components or greenhouse gasses upon thaw. The Goldstream watershed in interior Alaska is underlain by discontinuous permafrost with varying stage of talik (thaw bulb) development, allowing for the comparison of thaw stage on DOM composition. Surface water samples were collected from lakes and streams in regions of the watershed with varying degrees of permafrost thaw in order to investigate seasonal variability and associated trends in DOM composition. Additionally, select permafrost cores were obtained and utilized in leachate experiments to identify the fraction and reactivity of the soil organic carbon pool leached from active layer and permafrost soil upon thaw. Leached organic moieties were compared to the total permafrost organic carbon pool and the DOM of the overlying surface water. Extracted isolates from both permafrost and active layer were characterized by 3D excitation-emission fluorescence, UV-vis spectroscopy, PARAFAC, SPR-W5-WATERGATE 1H- NMR, total organic carbon, ICP-MS, and ion chromatography, coupled with photolysis experiments to determine reactive oxygen species production to characterize potential reactivity. Differences in carbon pool composition were resolved between seasons and with the extent of permafrost thaw. This is a key first step to determine how permafrost degradation influences DOM pool composition on a molecular level, which is essential for assessing permafrost organic matter impact on biogeochemical cycling and other ecological functions as it becomes incorporated into a warming landscape.

  11. [Transitory transesophageal atrial electric stimulation. Preliminary report on 19 cases and considerations on the method, indications and results (author's transl)].

    Science.gov (United States)

    Pistolese, M; Richichi, G; Catalano, V; Boccadamo, R

    1975-01-01

    Literature provides sufficient evidence that transitory electric stimulation via esophagus (SATE) - after the first positive experimental attempts on dogs - can be applied to man with a simple, rapid and harmless method. The study covers 19 patients subjected to high frequency transesophageal atrial stimulation by way of a bipolar electrode inserted through a nasogastric tube and connected to an external generator capable of producing tension impulses. Said impulses are variable up to 150 volts, lasting 2.5 microsec. with a frequency of up to 450/min. The 19 patients can be divided into 2 groups. The first including 15 patients on which SATE was effected for diagnostic purposes: in coronary deficiency (8 patients), in the disease of sinus node (3 patients), and lastly in the research for the A-V-block latent in 4 patients with acute post-infarctual A-V-block which regressed during the immediate clinical course of the illness. The other group includes 4 patients in which the atrial stimulation indication was the treatment of rapid, paroxysmic atrial rhythms, inaffected by drugs. By using impulses of 25-30 volts, the AA. have obtained a stable stimulation.

  12. Target enhancement and distractor inhibition affect transitory surround suppression in dual tasks using multiple rapid serial visual presentation streams.

    Science.gov (United States)

    Wu, Xia; Greenwood, Pamela; Fu, Shimin

    2016-01-01

    Few studies have investigated the interaction between temporal and spatial dimensions on selective attention using dual tasks in the multiple rapid serial visual presentation (RSVP) paradigm. A phenomenon that the surround suppression in space changes over time (termed transitory surround suppression, TSS, in the present study) has been observed, suggesting the existence of this time-space interaction. However, it is still unclear whether target enhancement or distractor inhibition modulates TSS. Four behavioural experiments were conducted to investigate the mechanism of TSS by manipulating the temporal lag and spatial distance factors between two targets embedded in six RSVP streams. The TSS effect was replicated in a study that eliminated confounds of perceptual effects and attentional switch (Experiment 1). However, the TSS disappeared when two targets shared the same colour in a between-subjects design (Experiment 2a) and a within-subject design (Experiment 2b), suggesting the impact of target enhancement on TSS. Moreover, the TSS was larger for within-category than for between-category distractors (Experiment 3), indicating the impact of distractor inhibition on TSS. These two influences on TSS under different processing demands of target and distractor processing were further confirmed in a skeletal design (Experiment 4). Overall, combinative effects of target enhancement and distractor suppression contribute to the mechanisms of time-space interaction in selective attention during visual search.

  13. Controlled Aerodynamic Loads on an Airfoil in Coupled Pitch/Plunge by Transitory Regulation of Trapped Vorticity

    Science.gov (United States)

    Tan, Yuehan; Crittenden, Thomas; Glezer, Ari

    2017-11-01

    The aerodynamic loads on an airfoil moving in coupled, time-periodic pitch-plunge beyond the static stall margin are controlled using transitory regulation of trapped vorticity concentrations. Actuation is effected by a spanwise array of integrated miniature chemical (combustion based) impulse actuators that are triggered intermittently during the airfoil's motion and have a characteristic time scale that is an order of magnitude shorter than the airfoil's convective time scale. Each actuation pulse effects momentary interruption and suspension of the vorticity flux with sufficient control authority to alter the airfoil's global aerodynamic characteristics throughout its motion cycle. The effects of the actuation are assessed using time-dependent measurements of the lift and pitching moment coupled with time-resolved particle image velocimetry over the airfoil and in its near wake that is acquired phased-locked to its motion. It is shown that while the presence of the pitch-coupled plunge delays lift and moment stall during upstroke, it also delays flow reattachment during the downstroke and results in significant degradation of the pitch stability. These aerodynamic shortcomings are mitigated using superposition of a limited number of pulses that are staged during the pitch/plunge cycle and lead to enhancement of cycle lift and pitch stability, and reduces the cycle hysteresis and peak pitching moment.

  14. Numerical Model of Transitory Flood Flow in 2005 on River Timis

    Science.gov (United States)

    Ghitescu, Marie-Alice; Lazar, Gheorghe; Titus Constantin, Albert; Nicoara, Serban-Vlad

    2017-10-01

    The paper presents numerical modelling of fluid flow transiting on the Timis River, downstream Lugoj section - N.H. COSTEIU, the occurrence of accidental flood waves from 4 April to 11 April 2005. Numerical simulation aims to estimate water levels on the route pattern on some areas and areas associated respectively floodplain adjacent construction site on the right bank of Timis river, on existing conditions in 2005. The model simulation from 2005 flood event shows that the model can be used for future inundation studies in this locality.

  15. THE PARTICIPATION OF THE NITRERGIC PATHWAY IN INCREASED RATE OF TRANSITORY RELAXATION OF LOWER ESOPHAGEAL SPHINCTER INDUCED BY RECTAL DISTENSION IN DOGS

    Directory of Open Access Journals (Sweden)

    Michel Santos PALHETA

    2014-04-01

    Full Text Available Context The rectal distension in dogs increases the rate of transitory lower esophageal sphincter relaxation considered the main factor causing gastroesophageal reflux. Objectives The aim of this study was evaluate the participation of the nitrergic pathway in the increased transitory lower esophageal sphincter relaxation rate induced by rectal distension in anesthetized dogs. Methods Male mongrel dogs (n = 21, weighing 10-15 kg, were fasted for 12 hours, with water ad libitum. Thereafter, they were anesthetized (ketamine 10 mg.Kg-1 + xylazine 20 mg.Kg-1, so as to carry out the esophageal motility evaluation protocol during 120 min. After a 30-minute basal period, the animals were randomly intravenous treated whith: saline solution 0.15M (1ml.Kg-1, L-NAME (3 mg.Kg-1, L-NAME (3 mg.Kg-1 + L-Arginine (200 mg.Kg-1, glibenclamide (1 mg.Kg-1 or methylene blue (3 mg.Kg-1. Forty-five min after these pre-treatments, the rectum was distended (rectal distension, 5 mL.Kg-1 or not (control with a latex balloon, with changes in the esophageal motility recorded over 45 min. Data were analyzed using ANOVA followed by Student Newman-Keuls test. Results In comparison to the respective control group, rectal distension induces an increase in transitory lower esophageal sphincter relaxation. Pre-treatment with L-NAME or methylene blue prevents (P<0.05 this phenomenon, which is reversible by L-Arginine plus L-NAME. However, pretreating with glibenclamide failed to abolish this process. Conclusions Therefore, these experiments suggested, that rectal distension increases transitory lower esophageal sphincter relaxation in dogs via through nitrergic pathways.

  16. Active and passive seismic investigations in Alpine Permafrost at Hoher Sonnblick (Austria)

    Science.gov (United States)

    Steiner, Matthias; Maierhofer, Theresa; Pfeiler, Stefan; Chwatal, Werner; Behm, Michael; Reisenhofer, Stefan; Schöner, Wolfgang; Straka, Wolfgang; Flores Orozco, Adrian

    2017-04-01

    Different geophysical measurements have been applied at the Hoher Sonnblick study area to gain information about permafrost distribution as well as heterogeneities controlling heat circulation, in the frame of the ÖAW-AtmoPerm project, which aims at the understanding the impacts of atmospheric extreme events on the thermal state of the active layer. Electrical Resistivity Tomography (ERT) has been widely accepted as a suitable method to characterize permafrost processes; however, limitations are imposed due to the challenges to inject high current densities in the frozen periods and the loss of resolution of electrical images at depth require the application of further geophysical methods. To overcome such problems, we investigate here the application of active and seismic methods. Seismic campaigns were performed using permanent borehole and temporarily installed surface geophones. A total of 15 borehole geophones are installed at depths of 1 m, 2 m, 5 m, 10 m and 20 m in three boreholes which are separated by a horizontal distance of 30 m between each other. Active measurements utilized 41 surface and 15 borehole geophones and a total of 199 excitation points. Surface geophones were laid out along two crossing lines with lengths of 92 m and 64 m, respectively. The longer line was placed directly along the borehole transect and the shorter one was oriented perpendicular to it. Hammer blows were performed with a spacing of 1 m inline the geophones and 4 m in crosslines rotated by 45 degrees, permitting 3D acquisition geometry. In addition to the active sources, data loggers connected to the borehole geophones permitted the collection of continuous 36-hours datasets for two different thermal conditions. Seismic ambient noise interferometry is applied to this data and aims at the identification of velocity changes in the subsurface related to seasonal changes of the active layer. A potential source of ambient seismic energy is the noise excited by hikers and the

  17. The Last Glacial Ecosystems of North Siberia: Permafrost-Sealed Evidence from Fossiliferous Cryolithic Formations

    Science.gov (United States)

    Chlachula, Jiri

    2017-04-01

    Multi-proxy palaeoecology and geoarchaeology records released from degrading permafrost in the Yana River Basin and the tributary valleys (66-67°N) confirm the past existence of natural conditions for sustainment of the Pleistocene megafauna as well as the last glacial peopling of this sub-polar area. Well-preserved and taxonomically diverse large fossil fauna skeletal remains sealed in the Pleistocene colluvial and alluvial-plain formations in intact geological positions 10-20 m above the present river and scattered on gravelly river banks after their erosion from the primary geo-contexts attest to a high biotic potential of the Late Pleistocene (MIS 3-2) sub-Arctic forest-tundra. Pollen records from the ancient interstratified boggy sediments and megafauna coprolites (14C-dated to 41-38 ka BP) show a predominance of the Siberian larch, dwarf birch and willow in the local vegetation cover accompanied by grassy communities during the mid-Last Glacial stage not dissimilar from the present northern taiga forest. Articulated and humanly used/worked fauna bones (mammoth, rhinoceros, horse, bison and reindeer among other species) point to co-existence of the large animals with the Upper Palaeolithic people within the mosaic open riverine ecosystems of the late Last Ice Age. The time-trangressive macro-lithic stone industry produced from pre-selected river gravel cobbles document some specific ways of human environmental adjustment to past periglacial settings. Geomorphology and hydrogeology indices of field mappings in congruence with the long-term statistical meteorology data illustrate a steadily increasing annual temperature trend in the broader Yana-Adycha Basins (current MAT -14.5°C) that triggers accelerated permafrost thaw across the Verkhoyansk Region of NE Siberia, particularly the lowlands, similarly as in the Indigirka and Kolyma Basins further East. The regional fluvial discharge is most dynamic during late spring due to the cumulative effects of snow

  18. Holocene carbon stocks and carbon accumulation rates altered in soils undergoing permafrost thaw

    Science.gov (United States)

    Caitlin E. Hicks Pries; Edward A.G. Schuur; K. Grace Crummer

    2012-01-01

    Permafrost soils are a significant global store of carbon (C) with the potential to become a large C source to the atmosphere. Climate change is causing permafrost to thaw, which can affect primary production and decomposition, therefore affecting ecosystem C balance. We modeled decadal and millennial soil C inputs, decomposition constants, and C accumulation rates by...

  19. Response of CO2 exchange in a tussock tundra ecosystem to permafrost thaw and thermokarst development

    Science.gov (United States)

    Jason Vogel; Edward A.G. Schuur; Christian Trucco; Hanna. Lee

    2009-01-01

    Climate change in high latitudes can lead to permafrost thaw, which in ice-rich soils can result in ground subsidence, or thermokarst. In interior Alaska, we examined seasonal and annual ecosystem CO2 exchange using static and automatic chamber measurements in three areas of a moist acidic tundra ecosystem undergoing varying degrees of permafrost...

  20. Draft Genome Sequence of Methylocella silvestris TVC, a Facultative Methanotroph Isolated from Permafrost

    OpenAIRE

    Wang, Jing; Geng, Kan; Farhan Ul Haque, Muhammad; Crombie, Andrew; Street, Lorna E.; Wookey, Philip A.; Ma, Ke; Murrell, J. Colin; Pratscher, Jennifer

    2018-01-01

    Permafrost environments play a crucial role in global carbon and methane cycling. We report here the draft genome sequence of Methylocella silvestris TVC, a new facultative methanotroph strain, isolated from the Siksik Creek catchment in the continuous permafrost zone of Inuvik (Northwest Territories, Canada).

  1. Draft Genome Sequence of Methylocella silvestris TVC, a Facultative Methanotroph Isolated from Permafrost.

    Science.gov (United States)

    Wang, Jing; Geng, Kan; Farhan Ul Haque, Muhammad; Crombie, Andrew; Street, Lorna E; Wookey, Philip A; Ma, Ke; Murrell, J Colin; Pratscher, Jennifer

    2018-02-22

    Permafrost environments play a crucial role in global carbon and methane cycling. We report here the draft genome sequence of Methylocella silvestris TVC, a new facultative methanotroph strain, isolated from the Siksik Creek catchment in the continuous permafrost zone of Inuvik (Northwest Territories, Canada). Copyright © 2018 Wang et al.

  2. Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

    DEFF Research Database (Denmark)

    Swindles, Graeme T.; Amesbury, Matthew J.; Turner, T. Edward

    2015-01-01

    The melting of high-latitude permafrost peatlands is a major concern due to a potential positive feedback on global climate change. We examine the ecology of testate amoebae in permafrost peatlands, based on sites in Sweden (similar to 200 km north of the Arctic Circle). Multivariate statistical ...

  3. The effects of permafrost thaw on soil hydrologic, thermal, and carbon dynamics in an Alaskan peatland

    Science.gov (United States)

    Jonathan A. O' Donnell; M.Torre Jorgenson; Jennifer W. Harden; A.David McGuire; Mikhail Z. Kanevskiy; Kimberly P. Wickland

    2012-01-01

    Recent warming at high-latitudes has accelerated permafrost thaw in northern peatlands, and thaw can have profound effects on local hydrology and ecosystem carbon balance. To assess the impact of permafrost thaw on soil organic carbon (OC) dynamics, we measured soil hydrologic and thermal dynamics and soil OC stocks across a collapse-scar bog chronosequence in interior...

  4. Controls on the methane released through ebullition affected by permafrost degradation

    Science.gov (United States)

    S.J. Klapstein; M.R. Turetsky; A.D. McGuire; J.W. Harden; C.I. Czimczik; X. Xu; J.P. Chanton; J.M. Waddington

    2014-01-01

    Permafrost thaw in peat plateaus leads to the flooding of surface soils and the formation of collapse scar bogs, which have the potential to be large emitters of methane (CH4) from surface peat as well as deeper, previously frozen, permafrost carbon (C). We used a network of bubble traps, permanently installed 20 cm and 60 cm beneath the moss surface, to examine...

  5. Mapping ice-bonded permafrost with electrical methods in Sisimiut, West Greenland

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas

    2006-01-01

    Permafrost delineation and thickness determination is of great importance in engineering related projects in arctic areas. In this paper, 2D geoelectrical measurements are applied and evaluated for permafrost mapping in an area in West Greenland. Multi-electrode resistivity profiles (MEP) have been...... collected and are compared with borehole information. It is shown that the permafrost thickness in this case is grossly overestimated by a factor of two to three. The difference between the inverted 2D resistivity sections and the borehole information is explained by macro-anisotropy due to the presence...... of horizontal ice-lenses in the frozen clay deposits. It is concluded that where the resistivity method perform well for lateral permafrost mapping, great care should be taken in evaluating permafrost thickness based on 2D resistivity profiles alone. Additional information from boreholes or other geophysical...

  6. Solar Trigeneration: a Transitory Simulation of HVAC Systems Using Different Typologies of Hybrid Panels

    Directory of Open Access Journals (Sweden)

    Alejandro del Amo Sancho

    2014-03-01

    Full Text Available The high energy demand on buildings requires efficient installations and the integration of renewable energy to achieve the goal of reducing energy consumption using traditional energy sources. Usually, solar energy generation and heating loads have different profiles along a day and their maximums take place at different moments. In addition, in months in which solar production is higher, the heating demands are the minimum (hot water is consumed only domestically in summer. Cooling machines (absorption and adsorption allow using thermal energy to chill a fluid. This heat flow rate could be recovered from solar collectors or any other heat source. The aim of this study is to integrate different typologies of solar hybrid (photovoltaic and thermal collectors with cooling machines getting solar trigeneration and concluding the optimal combination for building applications. The heat recovered from the photovoltaic module is used to provide energy to these cooling machines getting a double effect: to get a better efficiency on PV modules and to cool the building. In this document the authors analyse these installations, their operating conditions, dimensions and parameters, in order to get the optimal installation in three different European cities. This work suggests that in a family house in Madrid, the optimal combination is to use CPVT with azimuthally tracking and absorption machine. In this case, the solar trigeneration system using 55 m2 of collector area saves the cooling loads and 79% of the heating load in the house round the year.

  7. A national strategy for a long-term monitoring of permafrost and periglacial processes and their relationship to natural hazard prevention in Austria

    Science.gov (United States)

    Kellerer-Pirklbauer, Andreas; Bartsch, Annett; Gitschthaler, Christoph; Reisenhofer, Stefan; Weyss, Gernot; Riedl, Claudia; Avian, Michael

    2016-04-01

    About 2.5% (~2000 km²) of the national territory of Austria is influenced by permafrost conditions. A slightly smaller area of Austria is additionally affected by deep seasonal frost which is, however, similarly exposed to intensive physical weathering and related geomorphic processes. Currently, 23 skiing resorts, 31 water reservoirs and 42 mountain huts are either directly or indirectly influenced by permafrost and associated processes in Austria as determined from regional permafrost models. Ground thermal changes most likely affect the ground stability and infrastructure in those areas. Therefore, changes in the distribution and characteristics of permafrost and seasonal frost are of high economic and ecological importance. A range of Austrian institutions are interested in systematic permafrost monitoring (several universities, geological surveys, the Austrian torrent and avalanche control agency or several different alpine clubs). However, to date no coordinated monitoring network has been established on a national scale and a strategy for long-term permafrost/periglacial observation did not exist so far. Such a national strategy has been developed in 2015 within the permAT project funded through the StartClim2014-program. During permAT an extensive literature review and data search as well as a workshop with 40 participants (scientists, stakeholder and policy maker) were accomplished. The workshop allowed the integration of national as well as international colleagues into the strategy development. Results of permAT clearly demonstrate that the number of present permafrost/periglacial monitoring sites is far too little in Austria. Only few alpine areas of Austria are well represented by the existing monitoring activities but large areas lack such instrumentations. Furthermore, permafrost boreholes exist at only three sites in central Austria (all contribution to the GTN-P network) and there is a lack of knowledge about thermal conditions and recent changes

  8. An observational investigation of transitory turbulence in the atmospheric boundary layer

    Science.gov (United States)

    Jensen, Derek D.

    Within the atmospheric boundary layer (ABL), atmospheric fluid flow is in a constant state of transition in both time and space. Under calm conditions through the mid-daytime hours and over quasi-uniform terrain, the temporal and spatial evolution of the atmosphere is gradual. The structure and governing equations are well understood, allowing for numerical models to accurately forecast the evolution of the ABL. Under nocturnal conditions, the atmospheric processes are more complicated, yet numerical models still perform reasonably well. When changes in the state of the atmosphere occur abruptly, whether in time or space, the fidelity of most numerical weather models diminishes appreciably. This occurs because many of the simplifying assumptions intrinsic in most numerical models are no longer valid. The objective of this dissertation is to use observational data collected within such transitions to gain more insight into the mechanisms responsible for the evolution of the rapidly evolving ABL. First, near-surface turbulence data are used to study countergradient heat fluxes that occur through the evening transition. The countergradient heat flux may be produced by the sign change of the sensible heat flux preceding the sign change of the local temperature gradient and vice versa. The phenomenon is studied by considering the budget equations of both temperature and sensible heat flux. The behaviour of the countergradient heat flux is governed by the surface and subsurface characteristics. The duration of the countergradient flux may be prognosed by considering a ratio of terms in the heat flux budget equation evaluated during the mid- to late afternoon. Next, data collected over an arid shallow slope (2-4°) are used to study the structure and onset of katabatic flow through the evening transition. The katabatic onset, jet velocity and jet height all show a large degree of interdiurnal variability. The slope-aligned budgets of momentum and potential temperature are

  9. Permafrost in Marine Deposits at Ilulissat Airport in Greenland, Revisited

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Ingeman-Nielsen, Thomas

    2008-01-01

    Ilulissat Airport was constructed in 1982 to 1984 after detailed geotechnical investigations as the construction site included up to 12 m thick basins of marine clay deposits. Despite soil temperatures of approx -3oC the soil appeared unfrozen from 4 to 5 m below ground surface due to a high...... residual salt content in the porewater. However, in the less saline top zone massive ice layers was found constituting up to 30 volume%. These formations representing a type example of saline permafrost caused the planned position of the runway to be shifted towards northwest and a removal of the layers...

  10. Viral impacts on microbial carbon cycling in thawing permafrost soils

    Science.gov (United States)

    Trubl, G. G.; Roux, S.; Bolduc, B.; Jang, H. B.; Emerson, J. B.; Solonenko, N.; Li, F.; Solden, L. M.; Vik, D. R.; Wrighton, K. C.; Saleska, S. R.; Sullivan, M. B.; Rich, V. I.

    2017-12-01

    Permafrost contains 30-50% of global soil carbon (C) and is rapidly thawing. While the fate of this C is unknown, it will be shaped in part by microbes and their associated viruses, which modulate host activities via mortality and metabolic control. To date, viral research in soils has been outpaced by that in aquatic environments, due to the technical challenges of accessing viruses as well as the dramatic physicochemical heterogeneity in soils. Here, we describe advances in soil viromics from our research on permafrost-associated soils, and their implications for associated terrestrial C cycling. First, we optimized viral resuspension-DNA extraction methods for a range of soil types. Second, we applied cutting-edge viral-specific informatics methods to recover viral populations, define their gene content, connect them to potential hosts, and analyze their relationships to environmental parameters. A total of 781 viral populations were recovered from size-fractionated virus samples of three soils along a permafrost thaw gradient. Ecological analyses revealed endemism as recovered viral populations were largely unique to each habitat and unlike those in aquatic communities. Genome- and network-based classification assigned these viruses into 226 viral clusters (VCs; genus-level taxonomy), 55% of which were novel. This increases the number of VCs by a third and triples the number of soil viral populations in the RefSeq database (currently contains 256 VCs and 316 soil viral populations). Genomic analyses revealed 85% of the genes were functionally unknown, though 5% of the annotatable genes contained C-related auxiliary metabolic genes (AMGs; e.g. glycoside hydrolases). Using sequence-based features and microbial population genomes, we were able to in silico predict hosts for 30% of the viral populations. The identified hosts spanned 3 phyla and 6 genera but suggested these viruses have species-specific host ranges as >80% of hosts for a given virus were in the same

  11. Co-occurrence patterns in aquatic bacterial communities across changing permafrost landscapes

    Science.gov (United States)

    Comte, J.; Lovejoy, C.; Crevecoeur, S.; Vincent, W. F.

    2016-01-01

    Permafrost thaw ponds and lakes are widespread across the northern landscape and may play a central role in global biogeochemical cycles, yet knowledge about their microbial ecology is limited. We sampled a set of thaw ponds and lakes as well as shallow rock-basin lakes that are located in distinct valleys along a north-south permafrost degradation gradient. We applied high-throughput sequencing of the 16S rRNA gene to determine co-occurrence patterns among bacterial taxa (operational taxonomic units, OTUs), and then analyzed these results relative to environmental variables to identify variables controlling bacterial community structure. Network analysis was applied to identify possible ecological linkages among the bacterial taxa and with abiotic and biotic variables. The results showed an overall high level of shared taxa among bacterial communities within each valley; however, the bacterial co-occurrence patterns were non-random, with evidence of habitat preferences. There were taxonomic differences in bacterial assemblages among the different valleys that were statistically related to dissolved organic carbon concentration, conductivity and phytoplankton biomass. Co-occurrence networks revealed complex interdependencies within the bacterioplankton communities and showed contrasting linkages to environmental conditions among the main bacterial phyla. The thaw pond networks were composed of a limited number of highly connected taxa. This "small world network" property would render the communities more robust to environmental change but vulnerable to the loss of microbial "keystone species". These highly connected nodes (OTUs) in the network were not merely the numerically dominant taxa, and their loss would alter the organization of microbial consortia and ultimately the food web structure and functioning of these aquatic ecosystems.

  12. Effects of bryophyte and lichen cover on permafrost soil temperature at large scale

    Science.gov (United States)

    Porada, Philipp; Ekici, Altug; Beer, Christian

    2017-04-01

    Bryophytes and lichens covering the soil surface at high latitudes act as an insulating layer, which has a net cooling effect on the soil and thereby protects permafrost. Climate change, however, may lead to changes in the average surface coverage of bryophytes and lichens. This can result in thawing of permafrost and an associated release of soil carbon to the atmosphere, which may cause a positive feedback on atmospheric CO2 concentration. Hence, it is crucial to predict the future large-scale response of bryophyte and lichen cover to climatic change at high latitudes. Current global land surface models, however, contain mostly empirical approaches to represent the surface cover of bryophytes and lichens, which makes it difficult to quantify its future extent and dynamics. Therefore, we integrate a process-based model of bryophyte and lichen growth into the global land surface model JSBACH (Jena Scheme for Biosphere-Atmosphere Coupling in Hamburg). Thereby, we explicitly simulate dynamic thermal properties of the bryophyte and lichen cover and their relation to environmental factors. To quantify the insulating effect of the cover on the soil, we compare simulations with and without simulated bryophyte and lichen cover. We estimate that the bryophyte and lichen cover exerts an average cooling effect of 2.7 K on temperature in the topsoil for the region north of 50o N under current climatic conditions. Locally, a cooling of up to 5.7 K may be reached. Furthermore, we show that using a simple, empirical representation of the bryophyte and lichen cover instead of a dynamic one results only in an average cooling of around 0.5 K. We conclude that bryophytes and lichens have a significant impact on soil temperature in high-latitude ecosystems and that dynamic thermal properties are necessary for a realistic representation of the cooling effect.

  13. Model for the analysis of transitories and stability of a BWR reactor with fuel of thorium; Modelo para el analisis de transitorios y de estabilidad de un reactor BWR con combustible de torio

    Energy Technology Data Exchange (ETDEWEB)

    Nunez C, A. [CNSNS, 03020 Mexico D.F. (Mexico)]. E-mail: anunezc@cnsns.gob.mx; Espinosa P, G. [UAM-I, 09340 Mexico D.F. (Mexico); Francois L, J.L. [Fac. de Ingenieria, UNAM 62550 Jiutepec, Morelos (Mexico)

    2004-07-01

    In this work it is described the thermo hydraulic and neutronic pattern used to simulate the behavior of a nucleus of thorium-uranium under different conditions of operation. The analysed nucleus was designed with base to assemblies that operate under the cover-seed concept. The pattern was proven to conditions of stationary state and transitory state. Here it is only presented the simulation of the one SCRAM manual and it is compared in the behavior of a nucleus with UO{sub 2}. Additionally one carries out an analysis of stability taking into account the four corners that define the area of stability of the map flow-power and to conditions of 100% of flow and 100% of power. The module of stability is based on the pattern of Lahey and Podowsky to estimate the drops of pressure during a perturbation. It is concludes that the behavior of this nucleus is not very different to the one shown by the nuclei loaded with the fuel of UO{sub 2}. (Author)

  14. Exogenous determinants of early-life conditions, and mortality later in life

    DEFF Research Database (Denmark)

    van den Berg, Gerard J; Doblhammer, Gabriele; Christensen, Kaare

    2009-01-01

    We analyze causal effects of conditions early in life on the individual mortality rate later in life. Conditions early in life are captured by transitory features of the macro-environment around birth, notably the state of the business cycle around birth, but also food price deviations, weather i...

  15. Uav Photogrammetry for Mapping and Monitoring of Northern Permafrost Landscapes

    Science.gov (United States)

    Fraser, R. H.; Olthof, I.; Maloley, M.; Fernandes, R.; Prevost, C.; van der Sluijs, J.

    2015-08-01

    Northern environments are changing in response to recent climate warming, resource development, and natural disturbances. The Arctic climate has warmed by 2-3°C since the 1950's, causing a range of cryospheric changes including declines in sea ice extent, snow cover duration, and glacier mass, and warming permafrost. The terrestrial Arctic has also undergone significant temperature-driven changes in the form of increased thermokarst, larger tundra fires, and enhanced shrub growth. Monitoring these changes to inform land managers and decision makers is challenging due to the vast spatial extents involved and difficult access. Environmental monitoring in Canada's North is often based on local-scale measurements derived from aerial reconnaissance and photography, and ecological, hydrologic, and geologic sampling and surveying. Satellite remote sensing can provide a complementary tool for more spatially comprehensive monitoring but at coarser spatial resolutions. Satellite remote sensing has been used to map Arctic landscape changes related to vegetation productivity, lake expansion and drainage, glacier retreat, thermokarst, and wildfire activity. However, a current limitation with existing satellite-based techniques is the measurement gap between field measurements and high resolution satellite imagery. Bridging this gap is important for scaling up field measurements to landscape levels, and validating and calibrating satellite-based analyses. This gap can be filled to a certain extent using helicopter or fixed-wing aerial surveys, but at a cost that is often prohibitive. Unmanned aerial vehicle (UAV) technology has only recently progressed to the point where it can provide an inexpensive and efficient means of capturing imagery at this middle scale of measurement with detail that is adequate to interpret Arctic vegetation (i.e. 1-5 cm) and coverage that can be directly related to satellite imagery (1-10 km2). Unlike satellite measurements, UAVs permit frequent

  16. UAV PHOTOGRAMMETRY FOR MAPPING AND MONITORING OF NORTHERN PERMAFROST LANDSCAPES

    Directory of Open Access Journals (Sweden)

    R. H. Fraser

    2015-08-01

    Full Text Available Northern environments are changing in response to recent climate warming, resource development, and natural disturbances. The Arctic climate has warmed by 2–3°C since the 1950’s, causing a range of cryospheric changes including declines in sea ice extent, snow cover duration, and glacier mass, and warming permafrost. The terrestrial Arctic has also undergone significant temperature-driven changes in the form of increased thermokarst, larger tundra fires, and enhanced shrub growth. Monitoring these changes to inform land managers and decision makers is challenging due to the vast spatial extents involved and difficult access. Environmental monitoring in Canada’s North is often based on local-scale measurements derived from aerial reconnaissance and photography, and ecological, hydrologic, and geologic sampling and surveying. Satellite remote sensing can provide a complementary tool for more spatially comprehensive monitoring but at coarser spatial resolutions. Satellite remote sensing has been used to map Arctic landscape changes related to vegetation productivity, lake expansion and drainage, glacier retreat, thermokarst, and wildfire activity. However, a current limitation with existing satellite-based techniques is the measurement gap between field measurements and high resolution satellite imagery. Bridging this gap is important for scaling up field measurements to landscape levels, and validating and calibrating satellite-based analyses. This gap can be filled to a certain extent using helicopter or fixed-wing aerial surveys, but at a cost that is often prohibitive. Unmanned aerial vehicle (UAV technology has only recently progressed to the point where it can provide an inexpensive and efficient means of capturing imagery at this middle scale of measurement with detail that is adequate to interpret Arctic vegetation (i.e. 1–5 cm and coverage that can be directly related to satellite imagery (1–10 km2. Unlike satellite measurements

  17. CryoGRIDequi - a new equilibrium permafrost model applied for Norway

    Science.gov (United States)

    Gisnås, K.; Etzelmuller, B.; Farbrot, H.; Westermann, S.; Schuler, T.

    2011-12-01

    The thermal regime of permafrost is likely to change significantly in response to the predicted climate warming, with associated warming and degradation of permafrost. Knowledge about the spatial distribution and temperatures of permafrost is therefore crucial to understand the associated geomorphological and bio-chemical consequences. Based on spatially distributed equilibrium models (CryoGRIDequi) this presentation will focus on the effect of snow cover and organic material on the regional distribution of permafrost in Norway. In Norway, the good availability of spatially distributed data on meteorological variables, vegetation, petrophysics and sediment cover allows for an implementation of soil models with relatively high resolution, in our case 1km2. CryoGRIDequi comprises implementations of both the TTOP-model and the Kudryavtsev approach. The model defines temperature at the top of permafrost from air temperatures based on seasonal n-factors, parameterizing the vegetation and snow cover, and the conductivity ratio between frozen and thawed states in the active layer. The models are run with operationally gridded temperature- and snow data from the period 1960-2010, provided by the Norwegian Meteorological Institute and the Norwegian Water and Energy Directorate (senorge.no). Parameterization of the model is based on data from several air/ground and snow depth stations established in various mountain sites. The modeling results are validated with 140 sites all over Norway measuring ground surface temperature, 20 shallow boreholes equipped with temperature monitoring logger devices and maps of palsa- and rock glacier locations. The modeled permafrost distribution is in good agreement with observations. Sporadic permafrost under organic cover, which is absent in previous regional modeling procedures, is now well reproduced. According to the model results, approximately 6% of the total mainland area in Norway is presently underlain by permafrost. Of the total

  18. Changes to the Carbon and Energy fluxes in a Northern Peatland with Thawing Permafrost

    Science.gov (United States)

    Harder, S. R.; Roulet, N. T.; Crill, P. M.; Strachan, I. B.

    2017-12-01

    The maintenance of thaw of high carbon density landscapes in the permafrost region ultimately depends of how the energy balance is partitioned as temperatures and precipitation change, yet there are comparatively few energy balance studies, especially in peatlands that contain permafrost. While permafrost peatlands are currently net sinks of carbon, as Arctic temperatures rise and permafrost thaws, the future of these ecosystems and their capacity for carbon uptake is in question. Since 2012 we have been measuring the spatially integrated CO2, energy and water vapour fluxes from the Stordalen peatland (68°22'N, 19°03'E) using eddy covariance (EC). The Stordalen peatland is a heterogeneous peatland in the discontinuous permafrost zone where permafrost thaw is actively occurring, resulting in large changes to the landscape from year to year. Areas where permafrost is present are elevated by up to 1.5 m compared to the areas where permafrost has thawed causing differences in water table depth, peat temperatures, snow distribution, vegetation community and therefore in the carbon and energy fluxes. Our EC tower is located on the edge of a permafrost peat plateau (or palsa) where one fetch measures fluxes from an area underlain by permafrost and the other fetch sees the portion of the peatland where the permafrost has thawed. Within each sector, we have an array of soil temperature and water content sensors to determine the physical characteristics of each fetch. Extensive vegetation surveys (based on plant functional types or PFTs) have also been conducted to run a footprint analysis on the flux data to complete a comparative analysis of the magnitude and variability of the carbon and energy exchanges from PFT. The footprint analysis allows us to explain the difference in energy and carbon fluxes by examining the ecological, biogeochemical and physical characteristics within each footprint. We see distinctly different energy partitioning between the fetches

  19. New observations indicate the possible presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco

    Directory of Open Access Journals (Sweden)

    G. Vieira

    2017-07-01

    Full Text Available Relict and present-day periglacial features have been reported in the literature for the upper reaches of the High Atlas mountains, which is the highest range in North Africa (Djebel Toubkal – 4167 m a.s.l.. A lobate feature in the Irhzer Ikhibi south at 3800 m a.s.l. has been previously interpreted as an active rock glacier, but no measurements of ground or air temperatures are known to exist for the area. In order to assess the possible presence of permafrost, we analyse data from June 2015 to June 2016 from two air temperature measurement sites at 2370 and 3210 m a.s.l. and from four ground surface temperature (GST sites at 3220, 3815, 3980 and 4160 m a.s.l. to characterize conditions along an altitudinal gradient along the Oued Ihghyghaye valley to the summit of the Djebel Toubkal. GSTs were collected at 1 h intervals, and the presence of snow cover at the monitoring sites was validated using Landsat 8 and Sentinel-2 imagery. Two field visits allowed for logger installation and collection and for assessing the geomorphological features in the area. The results show that snow plays a major role on the thermal regime of the shallow ground, inducing important spatial variability. The lowest site at 3220 m had a thermal regime characterized by frequent freeze–thaw cycles during the cold season but with few days of snow. When snow settled, the ground surface remained isothermal at 0 °C , indicating the absence of permafrost. The highest sites at 3980 and 4160 m a.s.l. showed very frequent freeze–thaw cycles and a small influence of the snow cover on GST, reflecting the lack of snow accumulation due to the wind-exposed settings on a ridge and on the summit plateau. The site located at 3815 m in the Irhzer Ikhibi south valley had a cold, stable thermal regime with GST varying from −4.5 to −6 °C from December to March, under a continuous snow cover. The site's location in a concave setting favours wind

  20. Thermokarst Associations with Landscape Characteristics in Arctic Alaska: Implications for Future Permafrost Degradation at Landscape to Regional Scales

    Science.gov (United States)

    Balser, A.; Jones, J. B.; Jorgenson, T.

    2010-12-01

    Permafrost degradation affects Arctic landscapes, and is controlled by myriad landscape characteristics. Thermokarst features can develop by catastrophic failure, gradual subsidence, or continual mass wasting and can be classified into discernible modes based upon mechanism, morphology and substrate characteristics. Relationships among landscape characteristics and several different modes of thermokarst provided strong predictors of regional scale thermokarst distribution. In the Brooks Range foothills of northern Alaska, several distinct modes of thermokarst predominated. Active-layer detachment slides were associated with 4-7° slopes, non-carbonate parent lithologies (particularly micaceous shale), ice-rich upper permafrost with >40 % segregation ice in a 20 cm horizon directly beneath the active layer, and non-tussock vegetation. Glacial thermokarst (including the central kettle lake and surrounding retrogressive thaw slumps), was confined to valley bottoms where glacial recession has deposited stagnate glacial ice typically insulated by ablation till, colluvial blankets, and peat. Thermo-erosional gullies occurred in landscapes that have substantial massive ice (typically wedges, although less commonly abundant segregated ice) and sustained surface water flow. Retrogressive thaw slumps not associated with buried glacial ice formed on 6-12° slopes with ice-rich permafrost containing >35 % visible segregated ice. These slumps occurred either on low hillslope positions along convex bluffs, or as secondary features extending uphill from pre-existing active-layer detachment slides. Observations indicate that thermokarst formation has three essential components: (1) sufficient volume of ground ice of varying morphologies; (2) a set of distinctive landscape conditions (e.g. surficial materials, slopes and gravitational energy, vegetation, and water flow); and (3) a triggering mechanism caused by unusual weather or a disturbance event, although glacial thermokarst

  1. The Global Terrestrial Network for Permafrost Database: metadata statistics and prospective analysis on future permafrost temperature and active layer depth monitoring site distribution

    Science.gov (United States)

    Biskaborn, B. K.; Lanckman, J.-P.; Lantuit, H.; Elger, K.; Streletskiy, D. A.; Cable, W. L.; Romanovsky, V. E.

    2015-03-01

    The Global Terrestrial Network for Permafrost (GTN-P) provides the first dynamic database associated with the Thermal State of Permafrost (TSP) and the Circumpolar Active Layer Monitoring (CALM) programs, which extensively collect permafrost temperature and active layer thickness data from Arctic, Antarctic and Mountain permafrost regions. The purpose of the database is to establish an "early warning system" for the consequences of climate change in permafrost regions and to provide standardized thermal permafrost data to global models. In this paper we perform statistical analysis of the GTN-P metadata aiming to identify the spatial gaps in the GTN-P site distribution in relation to climate-effective environmental parameters. We describe the concept and structure of the Data Management System in regard to user operability, data transfer and data policy. We outline data sources and data processing including quality control strategies. Assessment of the metadata and data quality reveals 63% metadata completeness at active layer sites and 50% metadata completeness for boreholes. Voronoi Tessellation Analysis on the spatial sample distribution of boreholes and active layer measurement sites quantifies the distribution inhomogeneity and provides potential locations of additional permafrost research sites to improve the representativeness of thermal monitoring across areas underlain by permafrost. The depth distribution of the boreholes reveals that 73% are shallower than 25 m and 27% are deeper, reaching a maximum of 1 km depth. Comparison of the GTN-P site distribution with permafrost zones, soil organic carbon contents and vegetation types exhibits different local to regional monitoring situations on maps. Preferential slope orientation at the sites most likely causes a bias in the temperature monitoring and should be taken into account when using the data for global models. The distribution of GTN-P sites within zones of projected temperature change show a high

  2. Ice-Wedge Polygon Formation Impacts Permafrost Carbon Storage and Vulnerability to Top-Down Thaw in Arctic Coastal Plain Soils

    Science.gov (United States)

    Jastrow, J. D.; Matamala, R.; Ping, C. L.; Vugteveen, T. W.; Lederhouse, J. S.; Michaelson, G. J.; Mishra, U.

    2017-12-01

    , permafrost C in areas dominated by this polygon type may be at greater risk for destabilization. Thus, accounting for geospatial distributions of ice-wedge polygon types and associated variations in C stocks and composition could improve observational estimates of regional C stocks and their vulnerability to changing climatic conditions.

  3. Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

    Science.gov (United States)

    Göckede, Mathias; Kittler, Fanny; Kwon, Min Jung; Burjack, Ina; Heimann, Martin; Kolle, Olaf; Zimov, Nikita; Zimov, Sergey

    2017-12-01

    Hydrologic conditions are a key factor in Arctic ecosystems, with strong influences on ecosystem structure and related effects on biogeophysical and biogeochemical processes. With systematic changes in water availability expected for large parts of the northern high-latitude region in the coming centuries, knowledge on shifts in ecosystem functionality triggered by altered water levels is crucial for reducing uncertainties in climate change predictions. Here, we present findings from paired ecosystem observations in northeast Siberia comprising a drained and a control site. At the drainage site, the water table has been artificially lowered by up to 30 cm in summer for more than a decade. This sustained primary disturbance in hydrologic conditions has triggered a suite of secondary shifts in ecosystem properties, including vegetation community structure, snow cover dynamics, and radiation budget, all of which influence the net effects of drainage. Reduced thermal conductivity in dry organic soils was identified as the dominating drainage effect on energy budget and soil thermal regime. Through this effect, reduced heat transfer into deeper soil layers leads to shallower thaw depths, initially leading to a stabilization of organic permafrost soils, while the long-term effects on permafrost temperature trends still need to be assessed. At the same time, more energy is transferred back into the atmosphere as sensible heat in the drained area, which may trigger a warming of the lower atmospheric surface layer.

  4. Permafrost-associated gas hydrate: is it really approximately 1% of the global system?

    Science.gov (United States)

    Ruppel, Carolyn

    2015-01-01

    Permafrost-associated gas hydrates are often assumed to contain ∼1 % of the global gas-in-place in gas hydrates based on a study26 published over three decades ago. As knowledge of permafrost-associated gas hydrates has grown, it has become clear that many permafrost-associated gas hydrates are inextricably linked to an associated conventional petroleum system, and that their formation history (trapping of migrated gas in situ during Pleistocene cooling) is consistent with having been sourced at least partially in nearby thermogenic gas deposits. Using modern data sets that constrain the distribution of continuous permafrost onshore5 and subsea permafrost on circum-Arctic Ocean continental shelves offshore and that estimate undiscovered conventional gas within arctic assessment units,16 the done here reveals where permafrost-associated gas hydrates are most likely to occur, concluding that Arctic Alaska and the West Siberian Basin are the best prospects. A conservative estimate is that 20 Gt C (2.7·1013 kg CH4) may be sequestered in permafrost-associated gas hydrates if methane were the only hydrate-former. This value is slightly more than 1 % of modern estimates (corresponding to 1600 Gt C to 1800 Gt C2,22) for global gas-in-place in methane hydrates and about double the absolute estimate (11.2 Gt C) made in 1981.26

  5. Degradation potentials of dissolved organic carbon (DOC) from thawed permafrost peat

    Science.gov (United States)

    Panneer Selvam, Balathandayuthabani; Lapierre, Jean-François; Guillemette, Francois; Voigt, Carolina; Lamprecht, Richard E.; Biasi, Christina; Christensen, Torben R.; Martikainen, Pertti J.; Berggren, Martin

    2017-04-01

    Global warming can substantially affect the export of dissolved organic carbon (DOC) from peat-permafrost to aquatic systems. The direct degradability of such peat-derived DOC, however, is poorly constrained because previous permafrost thaw studies have mainly addressed mineral soil catchments or DOC pools that have already been processed in surface waters. We incubated peat cores from a palsa mire to compare an active layer and an experimentally thawed permafrost layer with regard to DOC composition and degradation potentials of pore water DOC. Our results show that DOC from the thawed permafrost layer had high initial degradation potentials compared with DOC from the active layer. In fact, the DOC that showed the highest bio- and photo-degradability, respectively, originated in the thawed permafrost layer. Our study sheds new light on the DOC composition of peat-permafrost directly upon thaw and suggests that past estimates of carbon-dioxide emissions from thawed peat permafrost may be biased as they have overlooked the initial mineralization potential of the exported DOC.

  6. The use of capacitive resistivity imaging (CRI) for monitoring laboratory experiments simulating permafrost growth, persistence and thaw in bedrock

    Science.gov (United States)

    Kuras, O.; Uhlemann, S.; Krautblatter, M.; Murton, J.; Haslam, E.; Wilkinson, P.; Meldrum, P.

    2012-12-01

    Understanding the impact on bedrock properties of permafrost degradation as a result of climate change is of major interest in a number of areas, including the assessment of rising instability of high-altitude mountain rock walls. The remote sensing of rock walls with the primary aim of monitoring the spatial and temporal behaviour of rock temperature (and thus permafrost distribution) is an emerging field of research for geohazard mitigation where geophysical tomography has the potential to make a significant and lasting contribution. Recent work has shown that temperature-calibrated Electrical Resistivity Tomography (ERT) using galvanic sensors is capable of imaging recession and re-advance of rock permafrost in response to the ambient temperature regime, yet the use of galvanic sensors can impose practical limitations on field measurements. In this study, we evaluate the use of Capacitive Resistivity Imaging (CRI), a technique based upon low-frequency, capacitively-coupled measurements across permanently installed multi-sensor arrays, in order to emulate well-established ERT methodology, but without the need for galvanic contact on frozen soils or rocks. Numerical simulation of multi-sensor CRI measurements on the rock samples under a quasi-static electromagnetic regime allowed us initially to validate our measurement concept and prototype CRI instrumentation. We have subsequently applied CRI as well as conventional ERT to controlled long-term experiments in the Permafrost Laboratory at the University of Sussex, simulating permafrost growth, persistence and thaw in bedrock. Water-saturated samples of limestone and chalk (450 mm high, 300 mm × 300 mm wide) of varying porosity are being monitored. The lower half of each sample is maintained at temperatures below 0°C (simulating permafrost) and the upper half is cycled above and below 0°C (simulating seasonal thawing and freezing of the overlying active layer). Samples are instrumented with both capacitive and

  7. Permafrost and Active Layer Monitoring in the Maritime Antarctic: A Contribution to TSP and ANTPAS projects

    Science.gov (United States)

    Vieira, G.; Ramos, M.; Batista, V.; Caselli, A.; Correia, A.; Fragoso, M.; Gruber, S.; Hauck, C.; Kenderova, R.; Lopez-Martinez, J.; Melo, R.; Mendes-Victor, L. A.; Miranda, P.; Mora, C.; Neves, M.; Pimpirev, C.; Rocha, M.; Santos, F.; Blanco, J. J.; Serrano, E.; Trigo, I.; Tome, D.; Trindade, A.

    2008-12-01

    Permafrost and active layer monitoring in the Maritime Antarctic (PERMANTAR) is a Portuguese funded International Project that, in cooperation with the Spanish project PERMAMODEL, will assure the installation and the maintenance of a network of boreholes and active layer monitoring sites, in order to characterize the spatial distribution of the physical and thermal properties of permafrost, as well as the periglacial processes in Livingston and Deception Islands (South Shetlands). The project is part of the International Permafrost Association IPY projects Thermal State of Permafrost (TSP) and Antarctic and Sub-Antarctic Permafrost, Soils and Periglacial Environments (ANTPAS). It contributes to GTN-P and CALM-S networks. The PERMANTAR-PERMAMODEL permafrost and active layer monitoring network includes several boreholes: Reina Sofia hill (since 2000, 1.1m), Incinerador (2000, 2.3m), Ohridski 1 (2008, 5m), Ohridski 2 (2008, 6m), Gulbenkian-Permamodel 1 (2008, 25m) and Gulbenkian- Permamodel 2 (2008, 15m). For active layer monitoring, several CALM-S sites have been installed: Crater Lake (2006), Collado Ramos (2007), Reina Sofia (2007) and Ohridski (2007). The monitoring activities are accompanied by detailed geomorphological mapping in order to identify and map the geomorphic processes related to permafrost or active layer dynamics. Sites will be installed in early 2009 for monitoring rates of geomorphological activity in relation to climate change (e.g. solifluction, rockglaciers, thermokarst). In order to analyse the spatial distribution of permafrost and its ice content, electrical resistivity tomography (ERT), and seismic refraction surveys have been performed and, in early 2009, continuous ERT surveying instrumentation will be installed for monitoring active layer evolution. The paper presents a synthesis of the activities, as well as the results obtained up to the present, mainly relating to ground temperature monitoring and from permafrost characteristics and

  8. Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

    Science.gov (United States)

    Jorgenson, M. Torre; Harden, Jennifer; Kanevskiy, Mikhail; O'Donnell, Jonathan; Wickland, Kim; Ewing, Stephanie; Manies, Kristen; Zhuang, Qianlai; Shur, Yuri; Striegl, Robert G.; Koch, Josh

    2013-01-01

    The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to

  9. Interactive effects of wildfire and permafrost on microbial communities and soil processes in an Alaskan black spruce forest

    Science.gov (United States)

    Waldrop, M.P.; Harden, J.W.

    2008-01-01

    Boreal forests contain significant quantities of soil carbon that may be oxidized to CO2 given future increases in climate warming and wildfire behavior. At the ecosystem scale, decomposition and heterotrophic respiration are strongly controlled by temperature and moisture, but we questioned whether changes in microbial biomass, activity, or community structure induced by fire might also affect these processes. We particularly wanted to understand whether postfire reductions in microbial biomass could affect rates of decomposition. Additionally, we compared the short-term effects of wildfire to the long-term effects of climate warming and permafrost decline. We compared soil microbial communities between control and recently burned soils that were located in areas with and without permafrost near Delta Junction, AK. In addition to soil physical variables, we quantified changes in microbial biomass, fungal biomass, fungal community composition, and C cycling processes (phenol oxidase enzyme activity, lignin decomposition, and microbial respiration). Five years following fire, organic surface horizons had lower microbial biomass, fungal biomass, and dissolved organic carbon (DOC) concentrations compared with control soils. Reductions in soil fungi were associated with reductions in phenol oxidase activity and lignin decomposition. Effects of wildfire on microbial biomass and activity in the mineral soil were minor. Microbial community composition was affected by wildfire, but the effect was greater in nonpermafrost soils. Although the presence of permafrost increased soil moisture contents, effects on microbial biomass and activity were limited to mineral soils that showed lower fungal biomass but higher activity compared with soils without permafrost. Fungal abundance and moisture were strong predictors of phenol oxidase enzyme activity in soil. Phenol oxidase enzyme activity, in turn, was linearly related to both 13C lignin decomposition and microbial respiration

  10. Electron acceptor-based regulation of microbial greenhouse gas production from thawing permafrost

    DEFF Research Database (Denmark)

    Bak, Ebbe Norskov; Jones, Eleanor; Yde, Jacob Clement

    Permafrost contains about 35% of the global soil organic carbon (0-3 m depth). As a consequence of global warming, the active layer thickness is steadily increasing and its organic carbon is becoming available for degradation, causing a concomitant release of CO2 and CH4. The climate forcing...... of sulfate and iron and the microbial community structure regulate the production of CO2 and CH4 in thawing permafrost, and to elucidate how the rate of the organic carbon degradation changes with depth in permafrost-affected soils. This study improves our understanding of climate feedback mechanisms...

  11. Using dynamical downscaling to close the gap between global change scenarios and local permafrost dynamics

    DEFF Research Database (Denmark)

    Stendel, Martin; Romanovsky, Vladimir E.; Christensen, Jens H.

    2007-01-01

    that prevents a realistic description of soil characteristics, vegetation, and topography within a model grid box is the major limitation for use in permafrost modelling. We propose to narrow the gap between typical GCMs on one hand and local permafrost models on the other by introducing as an intermediate step......, in particular in mountainous regions. By using global climate change scenarios as driving fields, one can obtain permafrost dynamics in high temporal resolution on the order of years. For the 21st century under the IPCC SRES scenarios A2 and B2, we find an increase of mean annual ground temperature by up to 6 K...

  12. Role of transitory carbon reserves during adjustment to climate variability and source-sink imbalances in oil palm (Elaeis guineensis).

    Science.gov (United States)

    Legros, S; Mialet-Serra, I; Clement-Vidal, A; Caliman, J-P; Siregar, F A; Fabre, D; Dingkuhn, M

    2009-10-01

    Oil palm (Elaeis guineensis Jacq.) is a perennial, tropical, monocotyledonous plant characterized by simple architecture and low phenotypic plasticity, but marked by long development cycles of individual phytomers (a pair of one leaf and one inflorescence at its axil). Environmental effects on vegetative or reproductive sinks occur with various time lags depending on the process affected, causing source-sink imbalances. This study investigated how the two instantaneous sources of carbon assimilates, CO(2) assimilation and mobilization of transitory non-structural carbohydrate (NSC) reserves, may buffer such imbalances. An experiment was conducted in Indonesia during a 22-month period (from July 2006 to May 2008) at two contrasting locations (Kandista and Batu Mulia) using two treatments (control and complete fruit pruning treatment) in Kandista. Measurements included leaf gas exchange, dynamics of NSC reserves and dynamics of structural aboveground vegetative growth (SVG) and reproductive growth. Drought was estimated from a simulated fraction of transpirable soil water. The main sources of variation in source-sink relationships were (i) short-term reductions in light-saturated leaf CO(2) assimilation rate (A(max)) during seasonal drought periods, particularly in Batu Mulia; (ii) rapid responses of SVG rate to drought; and (iii) marked lag periods between 16 and 29 months of environmental effects on the development of reproductive sinks. The resulting source-sink imbalances were buffered by fluctuations in NSC reserves in the stem, which mainly consisted of glucose and starch. Starch was the main buffer for sink variations, whereas glucose dynamics remained unexplained. Even under strong sink limitation, no negative feedback on A(max) was observed. In conclusion, the different lag periods for environmental effects on assimilate sources and sinks in oil palm are mainly buffered by NSC accumulation in the stem, which can attain 50% (dw:dw) in stem tops. The resulting

  13. Water balance and hydrology research in a mountainous permafrost watershed in upland streams of the Kolyma River, Russia: a database from the Kolyma Water-Balance Station, 1948-1997

    Science.gov (United States)

    Makarieva, Olga; Nesterova, Nataliia; Lebedeva, Lyudmila; Sushansky, Sergey

    2018-04-01

    In 2018, 70 years have passed since the beginning of observations at the Kolyma Water-Balance Station (KWBS), a unique scientific research hydrological and permafrost catchment. The volume and duration (50 continuous years) of hydrometeorological standard and experimental data, characterizing the natural conditions and processes occurring in mountainous permafrost conditions, significantly exceed any counterparts elsewhere in the world. The data are representative of mountainous territory of the North-East of Russia. In 1997, the station was terminated, thereby leaving Russia without operating research watersheds in the permafrost zone. This paper describes the dataset containing the series of daily runoff from 10 watersheds with an area from 0.27 to 21.3 km2, precipitation, meteorological observations, evaporation from soil and snow, snow surveys, soil thaw and freeze depths, and soil temperature for the period 1948-1997. It also highlights the main historical stages of the station's existence, its work and scientific significance, and outlines the prospects for its future, where the Kolyma Water-Balance Station could be restored to the status of a scientific research watershed and become a valuable international centre for hydrological research in permafrost. The data are available at https://doi.org/10.1594/PANGAEA.881731" target="_blank">https://doi.org/10.1594/PANGAEA.881731.

  14. Determining the terrain characteristics related to the surface expression of subsurface water pressurization in permafrost landscapes using susceptibility modelling

    Science.gov (United States)

    Holloway, Jean E.; Rudy, Ashley C. A.; Lamoureux, Scott F.; Treitz, Paul M.

    2017-06-01

    Warming of the Arctic in recent years has led to changes in the active layer and uppermost permafrost. In particular, thick active layer formation results in more frequent thaw of the ice-rich transient layer. This addition of moisture, as well as infiltration from late season precipitation, results in high pore-water pressures (PWPs) at the base of the active layer and can potentially result in landscape degradation. To predict areas that have the potential for subsurface pressurization, we use susceptibility maps generated using a generalized additive model (GAM). As model response variables, we used active layer detachments (ALDs) and mud ejections (MEs), both formed by high PWP conditions at the Cape Bounty Arctic Watershed Observatory, Melville Island, Canada. As explanatory variables, we used the terrain characteristics elevation, slope, distance to water, topographic position index (TPI), potential incoming solar radiation (PISR), distance to water, normalized difference vegetation index (NDVI; ME model only), geology, and topographic wetness index (TWI). ALDs and MEs were accurately modelled in terms of susceptibility to disturbance across the study area. The susceptibility models demonstrate that ALDs are most probable on hill slopes with gradual to steep slopes and relatively low PISR, whereas MEs are associated with higher elevation areas, lower slope angles, and areas relatively far from water. Based on these results, this method identifies areas that may be sensitive to high PWPs and helps improve our understanding of geomorphic sensitivity to permafrost degradation.

  15. Determining the terrain characteristics related to the surface expression of subsurface water pressurization in permafrost landscapes using susceptibility modelling

    Directory of Open Access Journals (Sweden)

    J. E. Holloway

    2017-06-01

    Full Text Available Warming of the Arctic in recent years has led to changes in the active layer and uppermost permafrost. In particular, thick active layer formation results in more frequent thaw of the ice-rich transient layer. This addition of moisture, as well as infiltration from late season precipitation, results in high pore-water pressures (PWPs at the base of the active layer and can potentially result in landscape degradation. To predict areas that have the potential for subsurface pressurization, we use susceptibility maps generated using a generalized additive model (GAM. As model response variables, we used active layer detachments (ALDs and mud ejections (MEs, both formed by high PWP conditions at the Cape Bounty Arctic Watershed Observatory, Melville Island, Canada. As explanatory variables, we used the terrain characteristics elevation, slope, distance to water, topographic position index (TPI, potential incoming solar radiation (PISR, distance to water, normalized difference vegetation index (NDVI; ME model only, geology, and topographic wetness index (TWI. ALDs and MEs were accurately modelled in terms of susceptibility to disturbance across the study area. The susceptibility models demonstrate that ALDs are most probable on hill slopes with gradual to steep slopes and relatively low PISR, whereas MEs are associated with higher elevation areas, lower slope angles, and areas relatively far from water. Based on these results, this method identifies areas that may be sensitive to high PWPs and helps improve our understanding of geomorphic sensitivity to permafrost degradation.

  16. Hydrological patterns in warming permafrost: comparing results from a control and drained site on a floodplain tundra near Chersky, Northeast Siberia

    Science.gov (United States)

    Boelck, Sandra; Goeckede, Mathias; Hildebrandt, Anke; Vonk, Jorien; Heimann, Martin

    2017-04-01

    Permafrost areas represent a major reservoir for organic carbon. At the same time, permafrost ecosystems are very susceptible to changing climate conditions. The stability of this reservoir, i.e. changes in lateral and vertical carbon fluxes in permafrost ecosystems, largely depends on groundwater level, temperature and vegetation community. Particularly during summer when the soil thaws and a so-called active layer develops, fluctuations in carbon flux rates are often dominantly driven by water availability. Such dry soil conditions are expected to become more frequent in the future due to deepening active layers as a consequence of climate change. This could result in degradation of polygonal tundra landscape properties with channelled water transport pathways. Therefore, water table depth and the associated groundwater fluxes are crucial to understand transport patterns and to quantify the lateral export of carbon through an aquatic system. Consequently, a fundamental understanding of hydrological patterns on ecosystem structure and function is required to close the carbon balance of permafrost ecosystems. This study focuses on small-scale hydrological patterns and its influencing factors, such as topography and precipitation events. Near Chersky, Northeast Siberia, we monitored (i) a control site of floodplain tundra, and (ii) a drained site, characterised by a drainage ring which was constructed in 2004, to study the effects of water availability on the carbon cycle. This experimental disturbance simulates drainage effects following the degradation of ice-rich permafrost ecosystems under future climate change. Continuous monitoring of water table depth in drained and control areas revealed small-scale water table variations. At several key locations, we collected water samples to determine the isotopic composition (δ18O, δD) of surface water, suprapermafrost groundwater and precipitation. Furthermore, a weir at the drainage ditch was constructed to directly

  17. Phototrophic pigment diversity and picophytoplankton in permafrost thaw lakes

    Science.gov (United States)

    Przytulska, A.; Comte, J.; Crevecoeur, S.; Lovejoy, C.; Laurion, I.; Vincent, W. F.

    2016-01-01

    Permafrost thaw lakes (thermokarst lakes) are widely distributed across the northern landscape, and are known to be biogeochemically active sites that emit large amounts of carbon to the atmosphere as CH4 and CO2. However, the abundance and composition of the photosynthetic communities that fix CO2 have been little explored in this ecosystem type. In order to identify the major groups of phototrophic organisms and their controlling variables, we sampled 12 permafrost thaw lakes along a permafrost degradation gradient in northern Québec, Canada. Additional samples were taken from five rock-basin reference lakes in the region to determine if the thaw lakes differed in limnological properties and phototrophs. Phytoplankton community structure was determined by high-performance liquid chromatography analysis of their photoprotective and photosynthetic pigments, and autotrophic picoplankton concentrations were assessed by flow cytometry. One of the black-colored lakes located in a landscape of rapidly degrading palsas (permafrost mounds) was selected for high-throughput 18S rRNA sequencing to complement conclusions based on the pigment and cytometry analyses. The results showed that the limnological properties of the thaw lakes differed significantly from the reference lakes, and were more highly stratified. However, both waterbody types contained similarly diverse phytoplankton groups, with dominance of the pigment assemblages by fucoxanthin-containing taxa, as well as chlorophytes, cryptophytes and cyanobacteria. Chlorophyll a concentrations (Chl a) were correlated with total phosphorus (TP), and both were significantly higher in the thaw lakes (overall means of 3.3 µg Chl a L-1 and 34 µg TP L-1) relative to the reference lakes (2.0 µg Chl a L-1 and 8.2 µg TP L-1). Stepwise multiple regression of Chl a against the other algal pigments showed that it was largely a function of alloxanthin, fucoxanthin and Chl b (R2 = 0.85). The bottom waters of two of the thaw

  18. Suggested best practice for geotechnical characterisation of permafrost in the Nordic countries

    DEFF Research Database (Denmark)

    Agergaard, Frederik Ancker; Ingeman-Nielsen, Thomas; Foged, Niels Nielsen

    2012-01-01

    Even though permafrost is a specialty within Nordic geotechnical engineering, engineers and researcher will be faced with managing the consequences of projected climatic influences to construction design in permafrost areas. This requires the determination of the frozen soil engineering propertie...... properties should be preferred, while soil residual salinity should always be determined. The procedure for determination of strength and deformation properties should be subject to projected soil temperature at end of construction service lifetime.......Even though permafrost is a specialty within Nordic geotechnical engineering, engineers and researcher will be faced with managing the consequences of projected climatic influences to construction design in permafrost areas. This requires the determination of the frozen soil engineering properties...... largely influenced by the content of ice in the soil. This paper presents and discusses different methodologies for laboratory determination of the soil bulk density, ice content, unfrozen water content, strength and deformation properties as well as thermal properties from frozen soil core samples...

  19. Introduction to the special issue: permafrost and periglacial research from coasts to mountains

    Science.gov (United States)

    Schrott, Lothar; Humlum, Ole

    2017-09-01

    This special issue of Geomorphology includes eleven papers dealing with permafrost and periglacial research from coasts to mountains. The compilation represents a selection from 47 presentations (oral and posters) given at the 4th European Conference on Permafrost - IPA Regional Conference (EUCOP4, June 2014) in the session ;Periglacial Geomorphology;. Geomorphology as a leading journal for our discipline is particularly suitable to publish advances in permafrost and periglacial research with a focus on geomorphic processes. Since 1989 Geomorphology has published 121 special issues and two special issues are explicitly dedicated to permafrost and periglacial research, however, only with a focus on research in Antarctica. In this special issue we present papers from the Canadian Beaufort Sea, Alaska, Spitzbergen, central western Poland, the European Alps, the eastern Sudetes, the southern Carpathians, Nepal, and Antarctica.

  20. Minimum distribution of subsea ice-bearing permafrost on the US Beaufort Sea continental shelf

    Science.gov (United States)

    Brothers, Laura L.; Hart, Patrick E.; Ruppel, Carolyn D.

    2012-01-01

    Starting in Late Pleistocene time (~19 ka), sea level rise inundated coastal zones worldwide. On some parts of the present-day circum-Arctic continental shelf, this led to flooding and thawing of formerly subaerial permafrost and probable dissociation of associated gas hydrates. Relict permafrost has never been systematically mapped along the 700-km-long U.S. Beaufort Sea continental shelf and is often assumed to extend to ~120 m water depth, the approximate amount of sea level rise since the Late Pleistocene. Here, 5,000 km of multichannel seismic (MCS) data acquired between 1977 and 1992 were examined for high-velocity (>2.3 km s−1) refractions consistent with ice-bearing, coarse-grained sediments. Permafrost refractions were identified along sea ice-bearing permafrost, which does not extend seaward of 30 km offshore or beyond the 20 m isobath.

  1. Active Microwave Satellite Data for High Latitude Pan-Boreal/ Arctic Permafrost Monitoring

    Science.gov (United States)

    Bartsch, A.; Naeimi, V.; Park, S.-E.; Sabel, D.

    2009-11-01

    Circumpolar permafrost monitoring is currently largely based on in-situ measurements and modelling. The capabilities of satellite data with respect to operational monitoring need to be assessed. Within the ESA DUE Permafrost project a wide range of EO datasets will be explored and integrated in an information system with extensive involvement of the permafrost research community. This comprises pan-boreal/arctic to local scale products. This paper discusses the potential of active microwave satellite products (scatterometer and SAR) for permafrost modeling and monitoring on pan-boreal/arctic scale. This includes soil moisture and freeze/thaw. Water in the soil impacts the ground thermal regime. The currently available Metop ASCAT (C-band) data also allow the identification of long term surface wetness anomalies based on ERS as well as the detection of frozen ground status. The possibilities of MetOp ASCAT and ENVISAT ASAR Global Monitoring Mode for the latter application are explored in this paper.

  2. Microbial Insights into Shifting Methane Production Potential in Thawing Permafrost

    Science.gov (United States)

    Crossen, K.; Wilson, R.; Raab, N.; Neumann, R.; Chanton, J.; Saleska, S. R.; Rich, V. I.

    2017-12-01

    Permafrost, which stores 50% of global soil carbon, is thawing rapidly due to climate change, and resident microbes are contributing to changing carbon gas emissions. Predictions of the fate of carbon in these regions is poorly constrained; however, improved, careful mapping of microbial community members influencing CO2 and CH4 emissions will help clarify the system response to continued change. In order to more fully understand connections between the microbial communities, major geochemical transformations, and CO2 and CH4 emissions, peat cores were collected from the active layers of three permafrost habitats spanning a thaw gradient (collapsed palsa, bog, and fen) at Stordalen Mire, Abisko, Sweden. Anaerobic incubations of shallow and deep subsamples from these sites were performed, with time-course characterization of the changes in microbial communities, peat geochemistry, and carbon gas production. The latter were profiled with 16S rRNA amplicon sequencing, and targeted metagenomes. The communities within each habitat and depth were statistically distinct, and changed significantly over the course of the incubations. Acidobacteria was consistently the dominant bacterial phylum in all three habitat types. With increased thaw, the relative abundance of Actinobacteria tended to decrease, while Chloroflexi and Bacteroidetes increased with thaw. The relative abundance of methanogens increased with thaw and with depth within each habitat. Over time in the incubations, the richness of the communities tended to decrease. Homoacetogenesis (CO2 + H2 -> CH3COOH) has been documented in other peatlands, and homoacetogens can influence CH4 production by interacting with methanogens, competing with hydrogenotrophs while providing substrate for acetoclasts. Modelling of microbial reaction networks suggests potential for highest homoacetogenesis rates in the collapsed palsa, which also contains the highest relative abundances of lineages taxonomically affiliated with known

  3. Unraveling of permafrost hydrological variabilities on Central Qinghai-Tibet Plateau using stable isotopic technique.

    Science.gov (United States)

    Yang, Yuzhong; Wu, Qingbai; Hou, Yandong; Zhang, Zhongqiong; Zhan, Jing; Gao, Siru; Jin, Huijun

    2017-12-15

    Permafrost degradation on the Qinghai-Tibet Plateau (QTP) will substantially alter the surface runoff discharge and generation, which changes the recharge processes and influences the hydrological cycle on the QTP. Hydrological connections between different water bodies and the influence of thawing permafrost (ground ice) are not well understood on the QTP. This study applied water stable isotopic method to investigate the permafrost hydrological variabilities in Beiluhe Basin (BLB) on Central QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and near-surface ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost region. Results suggested that isotopic seasonalities in precipitation is evident, it is showing more positive values in summer seasons, and negative values in winter seasons. Stable isotopes of river flow are mainly distributed in the range of precipitation which is indicative of important replenishment from precipitation. δ 18 O, δD of thermokarst lakes are more positive than precipitation, indicating of basin-scale evaporation of lake water. Comparison of δ I values in different water bodies shows that hydrology of thermokarst lakes was related to thawing of permafrost (ground ice) and precipitation. Near-surface ground ice in BLB exhibits different isotopic characteristics, and generates a special δD-δ 18 O relationship (freezing line): δD=5.81δ 18 O-23.02, which reflects typical freezing of liquid water. From isotopic analysis, it is inferred that near-surface ground ice was mainly recharged by precipitation and active layer water. Stable isotopic and conceptual model is suggestive of striking hydrological connections between precipitation, river flow, thermokarst lake, and ground ice under degrading permafrost. This research provides fundamental comprehensions into the hydrological processes in permafrost regions on QTP, which should be considered

  4. Investigation of Soil and Vegetation Characteristics in Discontinuous Permafrost Landscapes Near Fairbanks, Alaska

    Science.gov (United States)

    2015-08-01

    J., and D. M. Roosa. 1991. The Vascular Plants of Iowa . Iowa City, IA: University of Iowa Press. Elias, T. E. 1980. The Complete Trees of...Organic Carbon in Sediment (Lloyd Kahn Method). Edison, NJ: U.S. Environmental Protection Agency, Region II, Environmental Services Division. Klute A... groundwater dynamics in discontinuous permafrost near Council, Alaska. Permafrost and Periglacial Processes 14 (2): 151–160. Zhang, T., R. G. Barry, K

  5. Scaling-up permafrost thermal measurements in western Alaska using an ecotype approach

    Directory of Open Access Journals (Sweden)

    W. L. Cable

    2016-10-01

    Full Text Available Permafrost temperatures are increasing in Alaska due to climate change and in some cases permafrost is thawing and degrading. In areas where degradation has already occurred the effects can be dramatic, resulting in changing ecosystems, carbon release, and damage to infrastructure. However, in many areas we lack baseline data, such as subsurface temperatures, needed to assess future changes and potential risk areas. Besides climate, the physical properties of the vegetation cover and subsurface material have a major influence on the thermal state of permafrost. These properties are often directly related to the type of ecosystem overlaying permafrost. In this paper we demonstrate that classifying the landscape into general ecotypes is an effective way to scale up permafrost thermal data collected from field monitoring sites. Additionally, we find that within some ecotypes the absence of a moss layer is indicative of the absence of near-surface permafrost. As a proof of concept, we used the ground temperature data collected from the field sites to recode an ecotype land cover map into a map of mean annual ground temperature ranges at 1 m depth based on analysis and clustering of observed thermal regimes. The map should be useful for decision making with respect to land use and understanding how the landscape might change under future climate scenarios.

  6. Permafrost Boundary Shift in Western Siberia May Not Modify Dissolved Nutrient Concentrations in Rivers

    Directory of Open Access Journals (Sweden)

    Sergey N. Vorobyev

    2017-12-01

    Full Text Available Identifying the landscape and climate factors that control nutrient export by rivers in high latitude regions is one of the main challenges for understanding the Arctic Ocean response to ongoing climate change. This is especially true for Western Siberian rivers, which are responsible for a significant part of freshwater and solutes delivery to the Arctic Ocean and are draining vast permafrost-affected areas most vulnerable to thaw. Forty-nine small- and medium-sized rivers (10–100,000 km2 were sampled along a 1700 km long N–S transect including both permafrost-affected and permafrost-free zones of the Western Siberian Lowland (WSL in June and August 2015. The N, P, dissolved organic and inorganic carbon (DOC and DIC, respectively, particular organic carbon (POC, Si, Ca, K, Fe, and Mn were analyzed to assess the role of environmental parameters, such as temperature, runoff, latitude, permafrost, bogs, lake, and forest coverage on nutrient concentration. The size of the watershed had no influence on nutrient concentrations in the rivers. Bogs and lakes retained nutrients whereas forests supplied P, Si, K, Ca, DIC, and Mn to rivers. The river water temperature was negatively correlated with Si and positively correlated with Fe in permafrost-free rivers. In permafrost-bearing rivers, the decrease in T northward was coupled with significant increases in PO4, Ptot, NH4, pH, DIC, Si, Ca, and Mn. North of the permafrost boundary (61° N, there was no difference in nutrient concentrations among permafrost zones (isolated, sporadic, discontinuous, and continuous. The climate warming in Western Siberia may lead to a permafrost boundary shift northward. Using a substituting space for time scenario, this may decrease or maintain the current levels of N, P, Si, K, Ca, DIC, and DOC concentrations in rivers of continuous permafrost zones compared to the present state. As a result, the export flux of nutrients by the small- and medium-sized rivers of the

  7. Shifts of methanogenic communities in response to permafrost thaw results in rising methane emissions and soil property changes.

    Science.gov (United States)

    Wei, Shiping; Cui, Hongpeng; Zhu, Youhai; Lu, Zhenquan; Pang, Shouji; Zhang, Shuai; Dong, Hailiang; Su, Xin

    2018-05-01

    Permafrost thaw can bring negative consequences in terms of ecosystems, resulting in permafrost collapse, waterlogging, thermokarst lake development, and species composition changes. Little is known about how permafrost thaw influences microbial community shifts and their activities. Here, we show that the dominant archaeal community shifts from Methanomicrobiales to Methanosarcinales in response to the permafrost thaw, and the increase in methane emission is found to be associated with the methanogenic archaea, which rapidly bloom with nearly tenfold increase in total number. The mcrA gene clone libraries analyses indicate that Methanocellales/Rice Cluster I was predominant both in the original permafrost and in the thawed permafrost. However, only species belonging to Methanosarcinales showed higher transcriptional activities in the thawed permafrost, indicating a shift of methanogens from hydrogenotrophic to partly acetoclastic methane-generating metabolic processes. In addition, data also show the soil texture and features change as a result of microbial reproduction and activity induced by this permafrost thaw. Those data indicate that microbial ecology under warming permafrost has potential impacts on ecosystem and methane emissions.

  8. Simulated Historical (1901-2010) Changes in the Permafrost Extent and Active Layer Thickness in the Northern Hemisphere

    Science.gov (United States)

    Guo, Donglin; Wang, Huijun

    2017-11-01

    A growing body of simulation research has considered the dynamics of permafrost, which has an important role in the climate system of a warming world. Previous studies have concentrated on the future degradation of permafrost based on global climate models (GCMs) or data from GCMs. An accurate estimation of historical changes in permafrost is required to understand the relations between changes in permafrost and the Earth's climate and to validate the results from GCMs. Using the Community Land Model 4.5 driven by the Climate Research Unit -National Centers for Environmental Prediction (CRUNCEP) atmospheric data set and observations of changes in soil temperature and active layer thickness and present-day areal extent of permafrost, this study investigated the changes in permafrost in the Northern Hemisphere from 1901 to 2010. The results showed that the model can reproduce the interannual variations in the observed soil temperature and active layer thickness. The simulated area of present-day permafrost fits well with observations, with a bias of 2.02 × 106 km2. The area of permafrost decreased by 0.06 (0.62) × 106 km2 decade-1 from 1901 to 2009 (1979 to 2009). A clear decrease in the area of permafrost was found in response to increases in air temperatures during the period from about the 1930s to the 1940s, indicating that permafrost is sensitive to even a temporary increase in temperature. From a regional perspective, high-elevation permafrost decreases at a faster rate than high-latitude permafrost; permafrost in China shows the fastest rate of decrease, followed by Alaska, Russia, and Canada. Discrepancies in the rate of decrease in the extent of permafrost among different regions were mostly linked to the sensitivity of permafrost in the regions to increases in air temperatures rather than to the amplitude of the increase in air temperatures. An increase in the active layer thickness of 0.009 (0.071) m decade-1 was shown during the period of 1901

  9. Change in Spatial Distribution of Permafrost in the Source Area of the Yellow River: A Numerical Prediction

    Science.gov (United States)

    Ma, S.; Sheng, Y.; Wu, J.; Hu, X.; Li, J.

    2017-12-01

    Permafrost plays an important role in the climate system through its influence on energy exchanges, hydrological processes, natural hazards and carbon budgets. As a response to the global warming, permafrost is degrading with various manifestations, such as increase in permafrost temperature, thickening of active layer, permafrost disappearance. The Source Area of the Yellow River is located in the mosaic transition zones of seasonally frozen ground, and discontinuous and continuous permafrost on the northeastern Qinghai-Tibet Plateau. Based on the prediction results of the climate model in the IPCC Fifth Assessment Report, this article attempts to forecast the change of the typical permafrost types in the SAYR by using the numerical simulation method. And we calculate the spatial distribution of permafrost in the past and predict the change trend of permafrost in the future. The results show that only a small part of the permafrost in this region has degraded in1972 2012 and the degraded area is about 279 km2. The seasonal frozen soil is mainly distributed in the valley of Re Qu, Xiaoyemaling and Tangchama in the south of the two lake basins. There is little area difference on the permafrost degrading into the seasonal frozen soil under the scenarios of RCP2.6, RCP6.0, RCP8.5 in 2050. The degrading area of permafrost is 2224 km2, 2347 km2, 2559 km2. They account for 7.5%, 7.9%, 8.6% of the Source Area, respectively. And the seasonal frozen soil is sporadically distributed in Lena Qu, Duo Qu, Baima Qu. They widely spread on Yeniugou, Yeniutan and four Madio lakes being located in the Yellow River valley of the eastern part of Ngoring Lake. In 2100, the area of permafrost degradation is 5636 km2, 9769 km2, 15548 km2. They accounts for 19%, 32.9% and 52.3% of the source area, respectively. The permafrost mainly degenerate in the area of Xingsuhai, Gamaletan, Duogerong. Permafrost influences hydrology by providing an impermeable barrier to the movement of liquid water

  10. Biomarker and carbon isotope constraints (δ13C, Δ14C) on sources and cycling of particulate organic matter discharged by large Siberian rivers draining permafrost areas

    International Nuclear Information System (INIS)

    Winterfeld, Maria

    2014-08-01

    Circumpolar permafrost soils store about half of the global soil organic carbon pool. These huge amounts of organic matter (OM) could accumulate due to low temperatures and water saturated soil conditions over the course of millennia. Currently most of this OM remains frozen and therefore does not take part in the active carbon cycle, making permafrost soils a globally important carbon sink. Over the last decades mean annual air temperatures in the Arctic increased stronger than the global mean and this trend is projected to continue. As a result the permafrost carbon pool is under climate pressure possibly creating a positive climate feedback due to the thaw-induced release of greenhouse gases to the atmosphere. Arctic warming will lead to increased annual permafrost thaw depths and Arctic river runoff likely resulting in enhanced mobilization and export of old, previously frozen soil-derived OM. Consequently, the great arctic rivers play an important role in global biogeochemical cycles by connecting the large permafrost carbon pool of their hinterlands with the arctic shelf seas and the Arctic Ocean. The first part of this thesis deals with particulate organic matter (POM) from the Lena Delta and adjacent Buor Khaya Bay. The Lena River in central Siberia is one of the major pathways translocating terrestrial OM from its southernmost reaches near Lake Baikal to the coastal zone of the Laptev Sea. The permafrost soils from the Lena catchment area store huge amounts of pre-aged OM, which is expected to be remobilized due to climate warming. To characterize the composition and vegetation sources of OM discharged by the Lena River, the lignin phenol and carbon isotopic composition (δ 13 C and Δ 14 C) in total suspended matter (TSM) from surface waters, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex) were analyzed. The lignin compositions of these samples are

  11. Gas-emission crater in Central Yamal, West Siberia, Russia, a new permafrost feature

    Science.gov (United States)

    Leibman, Marina; Kizyakov, Alexandr; Khomutov, Artem; Dvornikov, Yury; Streletskaya, Irina; Gubarkov, Anatoly

    2016-04-01

    The Yamal crater is a hole funnel-shaped on top and cylinder-shaped down to the bottom, surrounded by a parapet. Field study of the crater included size measurements, photo- video-documentation of the feature and the surrounding environment, and geochemical sampling. The upper part of the geological section within the crater consisted of stratified icy sediments, underlain by almost pure stratified ice of nearly vertical orientation of the layers. The volume of discharged material (volume of the void of the crater) was 6 times larger than the volume of material in the parapet. The difference was due to a significant amount of ice exposed in the walls of the crater, emitted to the surface and melted there. Remote sensing data was processes and validated by field observations to reveal the date of crater formation, previous state of the surface, evolution of the crater and environmental conditions of the surrounding area. Crater formed between 9 October and 1 November 2013. The initial size derived from Digital Elevation Model (DEM) had diameter of the vegetated rim 25-29 m. It turned through a sharp bend into a cylinder with close to vertical sides and diameter 15-16 m. Depth of the hole was impossible to estimate from DEM because of no light reaching walls in the narrow hole. By the time of initial observation in July 2014, water was found at the depth exceeding 50 m below the rim. In November 2014 this depth was 26 m. By September 2015 almost all the crater was flooded, with water surface about 5 m below the rim. The plan dimensions of the crater increased dramatically from initial 25-29 to 47-54 m in 2015. Thus, it took two warm seasons to almost entirely fill in the crater. We suppose that during the next 1-2 years parapet will be entirely destroyed, and as a result the crater will look like an ordinary tundra lake. Excluding impossible and improbable versions of the crater's development, the authors conclude that the origin of this crater can be attributed to

  12. Modelling Holocene peatland and permafrost dynamics with the LPJ-GUESS dynamic vegetation model

    Science.gov (United States)

    Chaudhary, Nitin; Miller, Paul A.; Smith, Benjamin

    2016-04-01

    Dynamic global vegetation models (DGVMs) are an important platform to study past, present and future vegetation patterns together with associated biogeochemical cycles and climate feedbacks (e.g. Sitch et al. 2008, Smith et al. 2001). However, very few attempts have been made to simulate peatlands using DGVMs (Kleinen et al. 2012, Tang et al. 2015, Wania et al. 2009a). In the present study, we have improved the peatland dynamics in the state-of-the-art dynamic vegetation model (LPJ-GUESS) in order to understand the long-term evolution of northern peatland ecosystems and to assess the effect of changing climate on peatland carbon balance. We combined a dynamic multi-layer approach (Frolking et al. 2010, Hilbert et al. 2000) with soil freezing-thawing functionality (Ekici et al. 2015, Wania et al. 2009a) in LPJ-GUESS. The new model is named LPJ-GUESS Peatland (LPJ-GUESS-P) (Chaudhary et al. in prep). The model was calibrated and tested at the sub-arctic mire in Stordalen, Sweden, and the model was able to capture the reported long-term vegetation dynamics and peat accumulation patterns in the mire (Kokfelt et al. 2010). For evaluation, the model was run at 13 grid points across a north to south transect in Europe. The modelled peat accumulation values were found to be consistent with the published data for each grid point (Loisel et al. 2014). Finally, a series of additional experiments were carried out to investigate the vulnerability of high-latitude peatlands to climate change. We find that the Stordalen mire will sequester more carbon in the future due to milder and wetter climate conditions, longer growing seasons, and the carbon fertilization effect. References: - Chaudhary et al. (in prep.). Modelling Holocene peatland and permafrost dynamics with the LPJ-GUESS dynamic vegetation model - Ekici A, et al. 2015. Site-level model intercomparison of high latitude and high altitude soil thermal dynamics in tundra and barren landscapes. The Cryosphere 9: 1343

  13. Evaluating climate variables, indexes and thresholds governing Arctic urban sustainability: case study of Russian permafrost regions

    Science.gov (United States)

    Anisimov, O. A.; Kokorev, V.

    2013-12-01

    Addressing Arctic urban sustainability today forces planners to deal with the complex interplay of multiple factors, including governance and economic development, demography and migration, environmental changes and land use, changes in the ecosystems and their services, and climate change. While the latter can be seen as a factor that exacerbates the existing vulnerabilities to other stressors, changes in temperature, precipitation, snow, river and lake ice, and the hydrological regime also have direct implications for the cities in the North. Climate change leads to reduced demand for heating energy, on one hand, and heightened concerns about the fate of the infrastructure built upon thawing permafrost, on the other. Changes in snowfall are particularly important and have direct implications for the urban economy, as together with heating costs, expenses for snow removal from streets, airport runways, roofs and ventilation corridors underneath buildings erected on pile foundations on permafrost constitute the bulk of the city's maintenance budget. Many cities are located in river valleys and are prone to flooding that leads to enormous economic losses and casualties, including human deaths. The severity of the northern climate has direct implications for demographic changes governed by regional migration and labor flows. Climate could thus be viewed as an inexhaustible public resource that creates opportunities for sustainable urban development. Long-term trends show that climate as a resource is becoming more readily available in the Russian North, notwithstanding the general perception that globally climate change is one of the challenges facing humanity in the 21st century. In this study we explore the sustainability of the Arctic urban environment under changing climatic conditions. We identify key governing variables and indexes and study the thresholds beyond which changes in the governing climatic parameters have significant impact on the economy

  14. Origin Of Methane Gas And Migration Through The Gas Hydrate Stability Zone Beneath The Permafrost Zone

    Science.gov (United States)

    Uchida, T.; Waseda, A.; Namikawa, T.

    2005-12-01

    In 1998 and 2002 Mallik wells were drilled at Mackenzie Delta in the Canadian Arctic that clarified the characteristics of gas hydrate-dominant sandy layers at depths from 890 to 1110 m beneath the permafrost zone. Continuous downhole well log data as well as visible gas hydrates have confirmed pore-space hydrate as intergranular pore filling within sandy layers whose saturations are up to 80% in pore volume, but muddy sediments scarcely contain. Plenty of gas hydrate-bearing sand core samples have been obtained from the Mallik wells. According to grain size distributions pore-space hydrate is dominant in medium- to very fine-grained sandy strata. Methane gas accumulation and original pore space large enough to occur within host sediments may be required for forming highly saturated gas hydrate in pore system. The distribution of a porous and coarser-grained host rock should be one of the important factors to control the occurrence of gas hydrate, as well as physicochemical conditions. Subsequent analyses in sedimentology and geochemistry performed on gas hydrate-bearing sandy core samples also revealed important geologic and sedimentological controls on the formation and concentration of natural gas hydrate. This appears to be a similar mode for conventional oil and gas accumulations. It is necessary for investigating subsurface fluid flow behaviors to evaluate both porosity and permeability of gas hydrate-bearing sandy sediments, and the measurements of water permeability for them indicate that highly saturated sands may have permeability of a few millidarcies. The isotopic data of methane show that hydrocarbon gas contained in gas hydrate is generated by thermogenic decomposition of kerogen in deep mature sediments. Based on geochemical and geological data, methane is inferred to migrate upward closely associated with pore water hundreds of meters into and through the hydrate stability zone partly up to the permafrost zone and the surface along faults and

  15. Spatial variability and its main controlling factors of the permafrost soil-moisture on the northern-slope of Bayan Har Mountains in Qinghai-Tibet Plateau

    Science.gov (United States)

    Cao, W.; Sheng, Y.

    2017-12-01

    The soil moisture movement is an important carrier of material cycle and energy flow among the various geo-spheres in the cold regions. It is very critical to protect the alpine ecology and hydrologic cycle in Qinghai-Tibet Plateau. Especially, it becomes one of the key problems to reveal the spatial-temporal variability of soil moisture movement and its main influence factors in earth system science. Thus, this research takes the north slope of Bayan Har Mountains in Qinghai-Tibet Plateau as a case study. The present study firstly investigates the change of permafrost moisture in different slope positions and depths. Based on this investigation, this article attempts to investigate the spatial variability of permafrost moisture and identifies the key influence factors in different terrain conditions. The method of classification and regression tree (CART) is adopted to identify the main controlling factors influencing the soil moisture movement. And the relationships between soil moisture and environmental factors are revealed by the use of the method of canonical correspondence analysis (CCA). The results show that: 1) the change of the soil moisture on the permafrost slope is divided into 4 stages, including the freezing stability phase, the rapid thawing phase, the thawing stability phase and the fast freezing phase; 2) this greatly enhances the horizontal flow in the freezing period due to the terrain slope and the freezing-thawing process. Vertical migration is the mainly form of the soil moisture movement. It leads to that the soil-moisture content in the up-slope is higher than that in the down-slope. On the contrary, the soil-moisture content in the up-slope is lower than that in the down-slope during the melting period; 3) the main environmental factors which affect the slope-permafrost soil-moisture are elevation, soil texture, soil temperature and vegetation coverage. But there are differences in the impact factors of the soil moisture in different

  16. Recent Progress in Mountain Permafrost Modelling using BTS in North America

    Science.gov (United States)

    Bonnaventure, P. P.; Lewkowicz, A. G.

    2009-04-01

    This presentation reports on progress in mapping and modelling mountain permafrost in North America over the past 5 years using the Basal Temperature of Snow (BTS) technique. It describes the methodology and some of the challenges in our current study aimed at modelling permafrost at a resolution of 30 x 30 m, for the entire southern half of the Yukon Territory, an area of 250 x 103 km2. This mountainous region differs from those in Europe and Asia by having a sparse population, very limited base-line information (such as climate data) and relatively low levels of infrastructure. However, major infrastructure projects, such as pipelines, roads, railways and mines are being proposed and climate change is expected to affect permafrost distribution and characteristics, including potentially triggering landslides and other natural hazards. The research involves developing BTS-based models validated using late-summer ground-truthing. Models have been created for three areas and work is currently underway in five other locations in the Yukon with possible future sites in northern British Columbia. Work to date has examined the suitability of the method in differing climatic zones, the interchangeability of models between areas, and the potential effects of climatic change. Current data collection is focused on the potential impact of atmospheric temperature inversions on permafrost distribution: each of the study areas has been equipped with a network of air, ground surface and permafrost surface temperature sensors as well as snow-depth monitoring devices, located within different topographic situations. Another challenge is the interpolation of permafrost probabilities between distant study areas: information developed from a data-base of more than 1500 rock glaciers is expected to help in this regard. The project, which is scheduled for completion within the next 12 months, will provide essential information relating to the spatial attributes and sensitivities of

  17. Dissolved organic matter composition of Arctic rivers: Linking permafrost and parent material to riverine carbon

    Science.gov (United States)

    O’Donnell, Jonathan A.; Aiken, George R.; Swanson, David K.; Santosh, Panda; Butler, Kenna; Baltensperger, Andrew P.

    2016-01-01

    Recent climate change in the Arctic is driving permafrost thaw, which has important implications for regional hydrology and global carbon dynamics. Permafrost is an important control on groundwater dynamics and the amount and chemical composition of dissolved organic matter (DOM) transported by high-latitude rivers. The consequences of permafrost thaw for riverine DOM dynamics will likely vary across space and time, due in part to spatial variation in ecosystem properties in Arctic watersheds. Here we examined watershed controls on DOM composition in 69 streams and rivers draining heterogeneous landscapes across a broad region of Arctic Alaska. We characterized DOM using bulk dissolved organic carbon (DOC) concentration, optical properties, and chemical fractionation and classified watersheds based on permafrost characteristics (mapping of parent material and ground ice content, modeling of thermal state) and ecotypes. Parent material and ground ice content significantly affected the amount and composition of DOM. DOC concentrations were higher in watersheds underlain by fine-grained loess compared to watersheds underlain by coarse-grained sand or shallow bedrock. DOC concentration was also higher in rivers draining ice-rich landscapes compared to rivers draining ice-poor landscapes. Similarly, specific ultraviolet absorbance (SUVA254, an index of DOM aromaticity) values were highest in watersheds underlain by fine-grained deposits or ice-rich permafrost. We also observed differences in hydrophobic organic acids, hydrophilic compounds, and DOM fluorescence across watersheds. Both DOC concentration and SUVA254 were negatively correlated with watershed active layer thickness, as determined by high-resolution permafrost modeling. Together, these findings highlight how spatial variations in permafrost physical and thermal properties can influence riverine DOM.

  18. Assessing and Projecting Greenhouse Gas Release due to Abrupt Permafrost Degradation

    Science.gov (United States)

    Saito, K.; Ohno, H.; Yokohata, T.; Iwahana, G.; Machiya, H.

    2017-12-01

    Permafrost is a large reservoir of frozen soil organic carbon (SOC; about half of all the terrestrial storage). Therefore, its degradation (i.e., thawing) under global warming may lead to a substantial amount of additional greenhouse gas (GHG) release. However, understanding of the processes, geographical distribution of such hazards, and implementation of the relevant processes in the advanced climate models are insufficient yet so that variations in permafrost remains one of the large source of uncertainty in climatic and biogeochemical assessment and projections. Thermokarst, induced by melting of ground ice in ice-rich permafrost, leads to dynamic surface subsidence up to 60 m, which further affects local and regional societies and eco-systems in the Arctic. It can also accelerate a large-scale warming process through a positive feedback between released GHGs (especially methane), atmospheric warming and permafrost degradation. This three-year research project (2-1605, Environment Research and Technology Development Fund of the Ministry of the Environment, Japan) aims to assess and project the impacts of GHG release through dynamic permafrost degradation through in-situ and remote (e.g., satellite and airborn) observations, lab analysis of sampled ice and soil cores, and numerical modeling, by demonstrating the vulnerability distribution and relative impacts between large-scale degradation and such dynamic degradation. Our preliminary laboratory analysis of ice and soil cores sampled in 2016 at the Alaskan and Siberian sites largely underlain by ice-rich permafrost, shows that, although gas volumes trapped in unit mass are more or less homogenous among sites both for ice and soil cores, large variations are found in the methane concentration in the trapped gases, ranging from a few ppm (similar to that of the atmosphere) to hundreds of thousands ppm We will also present our numerical approach to evaluate relative impacts of GHGs released through dynamic

  19. The Effects of Perchlorates on the Permafrost Methanogens: Implication for Autotrophic Life on Mars.

    Science.gov (United States)

    Shcherbakova, Viktoria; Oshurkova, Viktoria; Yoshimura, Yoshitaka

    2015-09-09

    The terrestrial permafrost represents a range of possible cryogenic extraterrestrial ecosystems on Earth-like planets without obvious surface ice, such as Mars. The autotrophic and chemolithotrophic psychrotolerant methanogens are more likely than aerobes to function as a model for life forms that may exist in frozen subsurface environments on Mars, which has no free oxygen, inaccessible organic matter, and extremely low amounts of unfrozen water. Our research on the genesis of methane, its content and distribution in permafrost horizons of different ages and origin demonstrated the presence of methane in permanently frozen fine-grained sediments. Earlier, we isolated and described four strains of methanogenic archaea of Methanobacterium and Methanosarcina genera from samples of Pliocene and Holocene permafrost from Eastern Siberia. In this paper we study the effect of sodium and magnesium perchlorates on growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. In this paper we study the effect of sodium and magnesium perchlorates on the growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. Furthermore, as shown in the studies strain M2(T) M. arcticum, probably can use perchlorate anion as an electron acceptor in anaerobic methane oxidation. Earth's subzero subsurface environments are the best approximation of environments on Mars, which is most likely to harbor methanogens; thus, a biochemical understanding of these pathways is expected to provide a basis for designing experiments to detect autotrophic methane-producing life forms on Mars.

  20. The Effects of Perchlorates on the Permafrost Methanogens: Implication for Autotrophic Life on Mars

    Directory of Open Access Journals (Sweden)

    Viktoria Shcherbakova

    2015-09-01

    Full Text Available The terrestrial permafrost represents a range of possible cryogenic extraterrestrial ecosystems on Earth-like planets without obvious surface ice, such as Mars. The autotrophic and chemolithotrophic psychrotolerant methanogens are more likely than aerobes to function as a model for life forms that may exist in frozen subsurface environments on Mars, which has no free oxygen, inaccessible organic matter, and extremely low amounts of unfrozen water. Our research on the genesis of methane, its content and distribution in permafrost horizons of different ages and origin demonstrated the presence of methane in permanently frozen fine-grained sediments. Earlier, we isolated and described four strains of methanogenic archaea of Methanobacterium and Methanosarcina genera from samples of Pliocene and Holocene permafrost from Eastern Siberia. In this paper we study the effect of sodium and magnesium perchlorates on growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. In this paper we study the effect of sodium and magnesium perchlorates on the growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. Furthermore, as shown in the studies strain M2T M. arcticum, probably can use perchlorate anion as an electron acceptor in anaerobic methane oxidation. Earth’s subzero subsurface environments are the best approximation of environments on Mars, which is most likely to harbor methanogens; thus, a biochemical understanding of these pathways is expected to provide a basis for designing experiments to detect autotrophic methane-producing life forms on Mars.

  1. Permafrost degradation and associated ground settlement estimation under 2 °C global warming

    Science.gov (United States)

    Guo, Donglin; Wang, Huijun

    2017-10-01

    Global warming of 2 °C above preindustrial levels has been considered to be the threshold that should not be exceeded by the global mean temperature to avoid dangerous interference with the climate system. However, this global mean target has different implications for different regions owing to the globally nonuniform climate change characteristics. Permafrost is sensitive to climate change; moreover, it is widely distributed in high-latitude and high-altitude regions where the greatest warming is predicted. Permafrost is expected to be severely affected by even the 2 °C global warming, which, in turn, affects other systems such as water resources, ecosystems, and infrastructures. Using air and soil temperature data from ten coupled model intercomparison project phase five models combined with observations of frozen ground, we investigated the permafrost thaw and associated ground settlement under 2 °C global warming. Results show that the climate models produced an ensemble mean permafrost area of 14.01 × 106 km2, which compares reasonably with the area of 13.89 × 106 km2 (north of 45°N) in the observations. The models predict that the soil temperature at 6 m depth will increase by 2.34-2.67 °C on area average relative to 1990-2000, and the increase intensifies with increasing latitude. The active layer thickness will also increase by 0.42-0.45 m, but dissimilar to soil temperature, the increase weakens with increasing latitude due to the distinctly cooler permafrost at higher latitudes. The permafrost extent will obviously retreat north and decrease by 24-26% and the ground settlement owing to permafrost thaw is estimated at 3.8-15 cm on area average. Possible uncertainties in this study may be mostly attributed to the less accurate ground ice content data and coarse horizontal resolution of the models.

  2. Soil organic carbon pools and stocks in permafrost-affected soils on the tibetan plateau.

    Science.gov (United States)

    Dörfer, Corina; Kühn, Peter; Baumann, Frank; He, Jin-Sheng; Scholten, Thomas

    2013-01-01

    The Tibetan Plateau reacts particularly sensitively to possible effects of climate change. Approximately two thirds of the total area is affected by permafrost. To get a better understanding of the role of permafrost on soil organic carbon pools and stocks, investigations were carried out including both discontinuous (site Huashixia, HUA) and continuous permafrost (site Wudaoliang, WUD). Three organic carbon fractions were isolated using density separation combined with ultrasonic dispersion: the light fractions (1.6 g cm(-3)) of mineral associated organic matter (MOM). The fractions were analyzed for C, N, and their portion of organic C. FPOM contained an average SOC content of 252 g kg(-1). Higher SOC contents (320 g kg(-1)) were found in OPOM while MOM had the lowest SOC contents (29 g kg(-1)). Due to their lower density the easily decomposable fractions FPOM and OPOM contribute 27% (HUA) and 22% (WUD) to the total SOC stocks. In HUA mean SOC stocks (0-30 cm depth) account for 10.4 kg m(-2), compared to 3.4 kg m(-2) in WUD. 53% of the SOC is stored in the upper 10 cm in WUD, in HUA only 39%. Highest POM values of 36% occurred in profiles with high soil moisture content. SOC stocks, soil moisture and active layer thickness correlated strongly in discontinuous permafrost while no correlation between SOC stocks and active layer thickness and only a weak relation between soil moisture and SOC stocks could be found in continuous permafrost. Consequently, permafrost-affected soils in discontinuous permafrost environments are susceptible to soil moisture changes due to alterations in quantity and seasonal distribution of precipitation, increasing temperature and therefore evaporation.

  3. Soil organic carbon pools and stocks in permafrost-affected soils on the tibetan plateau.

    Directory of Open Access Journals (Sweden)

    Corina Dörfer

    Full Text Available The Tibetan Plateau reacts particularly sensitively to possible effects of climate change. Approximately two thirds of the total area is affected by permafrost. To get a better understanding of the role of permafrost on soil organic carbon pools and stocks, investigations were carried out including both discontinuous (site Huashixia, HUA and continuous permafrost (site Wudaoliang, WUD. Three organic carbon fractions were isolated using density separation combined with ultrasonic dispersion: the light fractions (1.6 g cm(-3 of mineral associated organic matter (MOM. The fractions were analyzed for C, N, and their portion of organic C. FPOM contained an average SOC content of 252 g kg(-1. Higher SOC contents (320 g kg(-1 were found in OPOM while MOM had the lowest SOC contents (29 g kg(-1. Due to their lower density the easily decomposable fractions FPOM and OPOM contribute 27% (HUA and 22% (WUD to the total SOC stocks. In HUA mean SOC stocks (0-30 cm depth account for 10.4 kg m(-2, compared to 3.4 kg m(-2 in WUD. 53% of the SOC is stored in the upper 10 cm in WUD, in HUA only 39%. Highest POM values of 36% occurred in profiles with high soil moisture content. SOC stocks, soil moisture and active layer thickness correlated strongly in discontinuous permafrost while no correlation between SOC stocks and active layer thickness and only a weak relation between soil moisture and SOC stocks could be found in continuous permafrost. Consequently, permafrost-affected soils in discontinuous permafrost environments are susceptible to soil moisture changes due to alterations in quantity and seasonal distribution of precipitation, increasing temperature and therefore evaporation.

  4. Soil organic matter decomposition and temperature sensitivity after forest fire in permafrost regions in Canada

    Science.gov (United States)

    Aaltonen, Heidi; Palviainen, Marjo; Köster, Kajar; Berninger, Frank; Pumpanen, Jukka

    2017-04-01

    On the Northern Hemisphere, 24% of soils are underlain by permafrost. These soils contain 50% of the global soil carbon pool. The Northern Hemisphere is also the region which is predicted to be most affected by climate warming and this causes uncertainties over the future of the permafrost. It has been estimated that 25% of permafrost might thaw by 2100, exposing previously frozen carbon pools to decomposition. In addition, global warming is expected to cause increase in the frequency of wild fires, which further increase permafrost melting by removing the insulating organic surface layer. The amount of released soil carbon from permafrost soils after forest fire is affected by degradability and temperature sensitivity of the soil organic matter, as well as soil depth and the stage of succession. Yet the common effect of these factors remains unclear. We studied how soil respiration and its temperature sensitivity (Q10) vary in different depths and within time by taking soil samples from different fire chronosequence areas (burned 3, 25, 46 and 100 years ago) from permafrost region in Northern Canada (Yukon and Northwest Territories, along Dempster Highway). The samples from three different depths (5, 10 and 30 cm) were incubated in four different temperatures (1, 7, 13 and 19°C) over 24h. Our results showed that the CO2 fluxes followed the stages of succession, with recently burned sites having lowest rates. The organic matter at 5 cm depth proved to be more labile and temperature sensitive than in deeper depths. The Q10 values, however, did not differ between sites, excluding 30 cm at the most recently burned site that had a significantly higher Q10 value than the other sites. The results implicate that heterotrophic soil respiration decreases on permafrost regions during the first stages after forest fire. At the same time the temperature sensitivity in deeper soil layers may increase.

  5. Peculiarities of CO2 sequestration in the Permafrost area

    Science.gov (United States)

    Guryeva, Olga; Chuvilin, Evgeny; Moudrakovski, Igor; Lu, Hailong; Ripmeester, John; Istomin, Vladimir

    2010-05-01

    Natural gas and gas-condensate accumulations in North of Western Siberia contain an admixture of CO2 (about 0.5-1.0 mol.%). Recently, the development and transportation of natural gas in the Yamal peninsula has become of interest to Russian scientists. They suggest liquifaction of natural gas followed by delivery to consumers using icebreaking tankers. The technique of gas liquefaction requires CO2 to be absent from natural gas, and therefore the liquefaction technology includes the amine treatment of gas. This then leads to a problem with utilization of recovered CO2. It is important to note, that gas reservoirs in the northern part of Russia are situated within the Permafrost zone. The thickness of frozen sediment reaches 500 meters. That is why one of the promising places for CO2 storage can be gas-permeable collectors in under-permafrost horizons. The favorable factors for preserving CO2 in these places are as follows: low permeability of overlying frozen sediments, low temperatures, the existence of a CO2 hydrate stability zone, and the possibility of sequestration at shallow depths (less then 800-1000 meters). When CO2 (in liquid or gas phase) is pumped into the under-permafrost collectors it is possible that some CO2 migrates towards the hydrate stability zone and hydrate-saturated horizons can be formed. This can result on the one hand in the increase of effective capacity of the collector, and on the other hand, in the increase of isolating properties of cap rock. Therefore, CO2 injection sometimes can be performed without a good cap rock. In connection with the abovementioned, to elaborate an effective technology for CO2 injection it is necessary to perform a comprehensive experimental investigation with computer simulation of different utilization schemes, including the process of CO2 hydrate formation in porous media. There are two possible schemes of hydrate formation in pore medium of sediments: from liquid CO2 or the gas. The pore water in the

  6. Field information links permafrost carbon to physical vulnerabilities of thawing

    Science.gov (United States)

    Harden, Jennifer W.; Koven, Charles; Ping, Chien-Lu; Hugelius, Gustaf; McGuire, A. David; Camill, P.; Jorgenson, Torre; Kuhry, Peter; Michaelson, Gary; O'Donnell, Jonathan A.; Schuur, Edward A.G.; Tamocai, Charles; Johnson, K.; Grosse, G.

    2012-01-01

    Deep soil profiles containing permafrost (Gelisols) were characterized for organic carbon (C) and total nitrogen (N) stocks to 3m depths. Using the Community Climate System Model (CCSM4) we calculate cumulative probability functions (PDFs) for active layer depths under current and future climates. The difference in PDFs over time was multiplied by C and N contents of soil horizons in Gelisol suborders to calculate newly thawed C and N, Thawing ranged from 147 PgC with 10 PgN by 2050 (representative concentration pathway RCP scenario 4.5) to 436 PgC with 29 PgN by 2100 (RCP 8.5). Organic horizons that thaw are vulnerable to combustion, and all horizon types are vulnerable to shifts in hydrology and decomposition. The rates and extent of such losses are unknown and can be further constrained by linking field and modelling approaches. These changes have the potential for strong additional loading to our atmosphere, water resources, and ecosystems.

  7. Metagenomics Reveals Microbial Community Composition And Function With Depth In Arctic Permafrost Cores

    Science.gov (United States)

    Jansson, J.; Tas, N.; Wu, Y.; Ulrich, C.; Kneafsey, T. J.; Torn, M. S.; Hubbard, S. S.; Chakraborty, R.; Graham, D. E.; Wullschleger, S. D.

    2013-12-01

    The Arctic is one of the most climatically sensitive regions on Earth and current surveys show that permafrost degradation is widespread in arctic soils. Biogeochemical feedbacks of permafrost thaw are expected to be dominated by the release of currently stored carbon back into the atmosphere as CO2 and CH4. Understanding the dynamics of C release from permafrost requires assessment of microbial functions from different soil compartments. To this end, as part of the Next Generation Ecosystem Experiment in the Arctic, we collected two replicate permafrost cores (1m and 3m deep) from a transitional polygon near Barrow, AK. At this location, permafrost starts from 0.5m in depth and is characterized by variable ice content and higher pH than surface soils. Prior to sectioning, the cores were CT-scanned to determine the physical heterogeneity throughout the cores. In addition to detailed geochemical characterization, we used Illumina MiSeq technology to sequence 16SrRNA genes throughout the depths of the cores at 1 cm intervals. Selected depths were also chosen for metagenome sequencing of total DNA (including phylogenetic and functional genes) using the Illumina HiSeq platform. The 16S rRNA gene sequence data revealed that the microbial community composition and diversity changed dramatically with depth. The microbial diversity decreased sharply below the first few centimeters of the permafrost and then gradually increased in deeper layers. Based on the metagenome sequence data, the permafrost microbial communities were found to contain members with a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. The surface active layers had more representatives of Verrucomicrobia (potential methane oxidizers) whereas the deep permafrost layers were dominated by several different species of Actinobacteria. The latter are known to have a diverse metabolic capability and are able to adapt to stress by entering a dormant yet

  8. Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

    International Nuclear Information System (INIS)

    Torre Jorgenson, M; Harden, Jennifer; Manies, Kristen; Kanevskiy, Mikhail; Shur, Yuri; O’Donnell, Jonathan; Wickland, Kim; Striegl, Robert; Ewing, Stephanie; Zhuang Qianlai; Koch, Josh

    2013-01-01

    The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to

  9. Hydrochemistry and controlling mechanism of lakes in permafrost regions along the Qinghai-Tibet Engineering Corridor, China

    Science.gov (United States)

    Gao, Zeyong; Lin, Zhanju; Niu, Fujun; Luo, Jing; Liu, Minghao; Yin, Guoan

    2017-11-01

    Lakes are the main water resource for migrating animals and herdsmen in permafrost regions along the Qinghai-Tibet Engineering Corridor (QTEC) and play a crucial role in regulating the balance between regional surface water and groundwater. Hydrochemical properties also affect the soil environment, ecological conditions, and hydrological cycle. In this study, 127 water samples were collected from lakes to analyze hydrochemistry characteristics. The results are discussed in the context of relationships between water chemistry and local conditions including climate, topography, and geology. The results showed that 43.3% of lakes are fresh, 19.7% are brackish, 18.9% are saline, 17.3% are brine, and only 0.8% are bitter. The dominant cation is Na+, followed by Mg2 +, Ca2 +, and K+. The dominant anion is Cl-, followed by SO42 - and HCO3- in the northern section of study region; whereas Ca2 +, Na+, and HCO3- are the dominant ions in the lakes of the southern section. The higher concentrations of carbonate in the southern lakes reflect contributions from groundwater discharge. In contrast, the higher concentrations of sodium, chloride, and sulfate in the northern section indicate that they are dominated by the interaction of evaporates. Additionally, cation exchange, precipitation, and dissolution have also modified the distribution of hydrochemical compositions. Thermokarst processes, in particular, have induced changes in the hydrochemistry of lake waters in the permafrost regions of the QTEC, in that the ion concentrations are closely related to ground ice content. In the context of persistent climatic warming and steadily increasing anthropogenic activities, the salinity of lakes along the QTEC is likely to increase in the future.

  10. THCM Coupled Model for Hydrate-Bearing Sediments: Data Analysis and Design of New Field Experiments (Marine and Permafrost Settings)

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Marcelo J. [Texas A & M Univ., College Station, TX (United States); Santamarina, J. Carlos [King Abdullah Univ. of Science and Technology (Saudi Arabia)

    2017-02-14

    Gas hydrates are solid compounds made of water molecules clustered around low molecular weight gas molecules such as methane, hydrogen, and carbon dioxide. Methane hydrates form under pressure (P) and temperature (T) conditions that are common in sub-permafrost layers and in deep marine sediments. Stability conditions constrain the occurrence of gas hydrates to submarine sediments and permafrost regions. The amount of technically recoverable methane trapped in gas hydrate may exceed 104tcf. Gas hydrates are a potential energy resource, can contribute to climate change, and can cause large-scale seafloor instabilities. In addition, hydrate formation can be used for CO2 sequestration (also through CO2-CH4 replacement), and efficient geological storage seals. The experimental study of hydrate bearing sediments has been hindered by the very low solubility of methane in water (lab testing), and inherent sampling difficulties associated with depressurization and thermal changes during core extraction. This situation has prompted more decisive developments in numerical modeling in order to advance the current understanding of hydrate bearing sediments, and to investigate/optimize production strategies and implications. The goals of this research has been to addresses the complex thermo-hydro-chemo-mechanical THCM coupled phenomena in hydrate-bearing sediments, using a truly coupled numerical model that incorporates sound and proven constitutive relations, satisfies fundamental conservation principles. Analytical solutions aimed at verifying the proposed code have been proposed as well. These tools will allow to better analyze available data and to further enhance the current understanding of hydrate bearing sediments in view of future field experiments and the development of production technology.

  11. Thermal stability analysis under embankment with asphalt pavement and cement pavement in permafrost regions.

    Science.gov (United States)

    Junwei, Zhang; Jinping, Li; Xiaojuan, Quan

    2013-01-01

    The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8 m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results.

  12. Thermal Stability Analysis under Embankment with Asphalt Pavement and Cement Pavement in Permafrost Regions

    Directory of Open Access Journals (Sweden)

    Zhang Junwei

    2013-01-01

    Full Text Available The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8 m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results.

  13. Groundwater storage changes in arctic permafrost watersheds from GRACE and in situ measurements

    International Nuclear Information System (INIS)

    Muskett, Reginald R; Romanovsky, Vladimir E

    2009-01-01

    The Arctic permafrost regions make up the largest area component of the cryosphere. Observations from the Gravity Recovery and Climate Experiment (GRACE) mission offer to provide a greater understanding of changes in water mass within permafrost regions. We investigate a GRACE monthly time series, snow water equivalent from the special scanning microwave imager (SSM/I), vegetation water content and soil moisture from the advanced microwave scanning radiometer for the Earth observation system (AMSR-E) and in situ discharge of the Lena, Yenisei, Ob', and Mackenzie watersheds. The GRACE water equivalent mass change responded to mass loading by snow accumulation in winter and mass unloading by runoff in spring-summer. Comparison of secular trends from GRACE to runoff suggests groundwater storage increased in the Lena and Yenisei watersheds, decreased in the Mackenzie watershed, and was unchanged in the Ob' watershed. We hypothesize that the groundwater storage changes are linked to the development of closed- and open-talik in the continuous permafrost zone and the decrease of permafrost lateral extent in the discontinuous permafrost zone of the watersheds.

  14. Surface geophysical methods for characterising frozen ground in transitional permafrost landscapes

    Science.gov (United States)

    Briggs, Martin A.; Campbell, Seth; Nolan, Jay; Walvoord, Michelle Ann; Ntarlagiannis, Dimitrios; Day-Lewis, Frederick D.; Lane, John W.

    2017-01-01

    The distribution of shallow frozen ground is paramount to research in cold regions, and is subject to temporal and spatial changes influenced by climate, landscape disturbance and ecosystem succession. Remote sensing from airborne and satellite platforms is increasing our understanding of landscape-scale permafrost distribution, but typically lacks the resolution to characterise finer-scale processes and phenomena, which are better captured by integrated surface geophysical methods. Here, we demonstrate the use of electrical resistivity imaging (ERI), electromagnetic induction (EMI), ground penetrating radar (GPR) and infrared imaging over multiple summer field seasons around the highly dynamic Twelvemile Lake, Yukon Flats, central Alaska, USA. Twelvemile Lake has generally receded in the past 30 yr, allowing permafrost aggradation in the receded margins, resulting in a mosaic of transient frozen ground adjacent to thick, older permafrost outside the original lakebed. ERI and EMI best evaluated the thickness of shallow, thin permafrost aggradation, which was not clear from frost probing or GPR surveys. GPR most precisely estimated the depth of the active layer, which forward electrical resistivity modelling indicated to be a difficult target for electrical methods, but could be more tractable in time-lapse mode. Infrared imaging of freshly dug soil pit walls captured active-layer thermal gradients at unprecedented resolution, which may be useful in calibrating emerging numerical models. GPR and EMI were able to cover landscape scales (several kilometres) efficiently, and new analysis software showcased here yields calibrated EMI data that reveal the complicated distribution of shallow permafrost in a transitional landscape.

  15. Carbon loss and chemical changes from permafrost collapse in the northern Tibetan Plateau

    Science.gov (United States)

    Mu, Cuicui; Zhang, Tingjun; Zhang, Xiankai; Li, Lili; Guo, Hong; Zhao, Qian; Cao, Lin; Wu, Qingbai; Cheng, Guodong

    2016-07-01

    Permafrost collapse, known as thermokarst, can alter soil properties and carbon emissions. However, little is known regarding the effects of permafrost collapse in upland landscapes on the biogeochemical processes that affect carbon balance. In this study, we measured soil carbon and physiochemical properties at a large thermokarst feature on a hillslope in the northeastern Tibetan Plateau. We categorized surfaces into three different microrelief patches based on type and extent of collapse (control, drape, and exposed areas). Permafrost collapse resulted in substantial decreases of surface soil carbon and nitrogen stocks, with losses of 29.6 ± 4.2% and 28.9 ± 3.1% for carbon and nitrogen, respectively, in the 0-10 cm soil layer. Laboratory incubation experiments indicated that control soil had significantly higher CO2 production rates than that of drapes. The results from Fourier transform infrared spectroscopy analysis showed that exposed soils accumulated some organic matter due to their low position within the feature, which was accompanied by substantial changes in the chemical structure and characteristics of the soil carbon. Exposed soils had higher hydrocarbon and lignin/phenol backbone content than in control and drape soils in the 0-10 cm layer. This study demonstrates that permafrost collapse can cause abundant carbon and nitrogen loss, potentially from mineralization, leaching, photodegradation, and lateral displacement. These results demonstrate that permafrost collapse redistributes the soil organic matter, changes its chemical characteristics, and leads to losses of organic carbon due to the greenhouse gas emission.

  16. Strong geologic methane emissions from discontinuous terrestrial permafrost in the Mackenzie Delta, Canada.

    Science.gov (United States)

    Kohnert, Katrin; Serafimovich, Andrei; Metzger, Stefan; Hartmann, Jörg; Sachs, Torsten

    2017-07-19

    Arctic permafrost caps vast amounts of old, geologic methane (CH 4 ) in subsurface reservoirs. Thawing permafrost opens pathways for this CH 4 to migrate to the surface. However, the occurrence of geologic emissions and their contribution to the CH 4 budget in addition to recent, biogenic CH 4 is uncertain. Here we present a high-resolution (100 m × 100 m) regional (10,000 km²) CH 4 flux map of the Mackenzie Delta, Canada, based on airborne CH 4 flux data from July 2012 and 2013. We identify strong, likely geologic emissions solely where the permafrost is discontinuous. These peaks are 13 times larger than typical biogenic emissions. Whereas microbial CH 4 production largely depends on recent air and soil temperature, geologic CH 4 was produced over millions of years and can be released year-round provided open pathways exist. Therefore, even though they only occur on about 1% of the area, geologic hotspots contribute 17% to the annual CH 4 emission estimate of our study area. We suggest that this share may increase if ongoing permafrost thaw opens new pathways. We conclude that, due to permafrost thaw, hydrocarbon-rich areas, prevalent in the Arctic, may see increased emission of geologic CH 4 in the future, in addition to enhanced microbial CH 4 production.

  17. Distribution of late Pleistocene ice-rich syngenetic permafrost of the Yedoma Suite in east and central Siberia, Russia

    Science.gov (United States)

    Grosse, Guido; Robinson, Joel E.; Bryant, Robin; Taylor, Maxwell D.; Harper, William; DeMasi, Amy; Kyker-Snowman, Emily; Veremeeva, Alexandra; Schirrmeister, Lutz; Harden, Jennifer

    2013-01-01

    This digital database is the product of collaboration between the U.S. Geological Survey, the Geophysical Institute at the University of Alaska, Fairbanks; the Los Altos Hills Foothill College GeoSpatial Technology Certificate Program; the Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany; and the Institute of Physical Chemical and Biological Problems in Soil Science of the Russian Academy of Sciences. The primary goal for creating this digital database is to enhance current estimates of soil organic carbon stored in deep permafrost, in particular the late Pleistocene syngenetic ice-rich permafrost deposits of the Yedoma Suite. Previous studies estimated that Yedoma deposits cover about 1 million square kilometers of a large region in central and eastern Siberia, but these estimates generally are based on maps with scales smaller than 1:10,000,000. Taking into account this large area, it was estimated that Yedoma may store as much as 500 petagrams of soil organic carbon, a large part of which is vulnerable to thaw and mobilization from thermokarst and erosion. To refine assessments of the spatial distribution of Yedoma deposits, we digitized 11 Russian Quaternary geologic maps. Our study focused on extracting geologic units interpreted by us as late Pleistocene ice-rich syngenetic Yedoma deposits based on lithology, ground ice conditions, stratigraphy, and geomorphological and spatial association. These Yedoma units then were merged into a single data layer across map tiles. The spatial database provides a useful update of the spatial distribution of this deposit for an approximately 2.32 million square kilometers land area in Siberia that will (1) serve as a core database for future refinements of Yedoma distribution in additional regions, and (2) provide a starting point to revise the size of deep but thaw-vulnerable permafrost carbon pools in the Arctic based on surface geology and the distribution of cryolithofacies types at high spatial

  18. Circumpolar assessment of permafrost C quality and its vulnerability over time using long-term incubation data

    DEFF Research Database (Denmark)

    Schädel, Christina; Schuur, Edward A.G.; Bracho, Rosvel

    2014-01-01

    High-latitude ecosystems store approximately 1700 Pg of soil carbon (C), which is twice as much C as is currently contained in the atmosphere. Permafrost thaw and subsequent microbial decomposition of permafrost organic matter could add large amounts of C to the atmosphere, thereby influencing th...

  19. Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems

    NARCIS (Netherlands)

    Hicks Pries, C.E.; van Logtestijn, R.S.P; Schuur, E.A.G.; Natali, S.M.; Cornelissen, J.H.C.; Aerts, R.; Dorrepaal, E.

    2015-01-01

    Soil carbon in permafrost ecosystems has the potential to become a major positive feedback to climate change if permafrost thaw increases heterotrophic decomposition. However, warming can also stimulate autotrophic production leading to increased ecosystem carbon storage-a negative climate change

  20. Simulation of permafrost changes due to technogenic influences of different ingeneering constructions used in nothern oil and gas fields

    Science.gov (United States)

    Filimonov, M. Yu; Vaganova, N. A.

    2016-10-01

    Significant amount of oil and gas is producted in Russian Federation on the territories with permafrost soils. Ice-saturated rocks thawing due to global warming or effects of various human activity will be accompanied by termocarst and others dangerous geological processes in permafrost. Design and construction of well pads in permafrost zones have some special features. The main objective is to minimize the influence of different heat sources (engineering objects) inserted into permafrost and accounting long-term forecast of development of permafrost degradation due to different factors in particular generated by human activity. In this work on the basis a mathematical model and numerical algorithms approved on 11 northern oil and gas fields some effects obtained by carrying out numerical simulations for various engineering systems are discussed.

  1. Future active layer dynamics and carbon dioxide production from thawing permafrost layers in Northeast Greenland

    DEFF Research Database (Denmark)

    Hollesen, Jørgen; Elberling, Bo; Jansson, P.E.

    2011-01-01

    from a moist permafrost soil in High-Arctic Greenland with observed heat production and carbon dioxide (CO2) release rates from decomposition of previously frozen organic matter. Observations show that the maximum thickness of the active layer at the end of the summer has increased 1 cm yr-1 since 1996......Thawing permafrost and the resulting mineralization of previously frozen organic carbon (C) is considered an important future feedback from terrestrial ecosystems to the atmosphere. Here, we use a dynamic process oriented permafrost model, the CoupModel, to link surface and subsurface temperatures......–105 cm as a result of a 2–6 °C warming. An additional increase in the maximum active layer thickness of a few centimetres may be expected due to heat production from decomposition of organic matter. Simulated future soil temperatures and water contents are subsequently used with measured basal soil...

  2. COLD HARDINESS AND RANGE OF THE MYRIAPOD Angarozonium amurense (POLYZONIIDAE, DIPLOPODA, ARTHROPODA) IN PERMAFROST ENVIRONMENTS.

    Science.gov (United States)

    Berman, D I; Meshcheryakova, E N; Mikhaljova, E V

    2015-01-01

    Angarozonium amurense (Gerstfeldt, 1859) is the only one out of more than a hundred diplopod species described in Siberia and the Far East that inhabits regions with solid permafrost. To evaluate the cold hardiness of A. amurense that allows this species to inhabit permafrost regions. The survival temperature thresholds and supercooling points (SCP) were measured. The temperature thresholds for adult animal survival are -8.5 C in summer and -27 C in winter. Average SCP decreases from -7.7 in summer to -16.9 in winter. Water content decreases from 55.7% in summer to 49.4% in winter. The cold hardiness of A. amurense sets the record in this class of animals. It allows it to overwinter in the upper 15 centimeters layer of soil in most biotopes of the coldest permafrost regions in North Asia.

  3. Coupling of snow and permafrost processes using the Basic Modeling Interface (BMI)

    Science.gov (United States)

    Wang, K.; Overeem, I.; Jafarov, E. E.; Piper, M.; Stewart, S.; Clow, G. D.; Schaefer, K. M.

    2017-12-01

    We developed a permafrost modeling tool based by implementing the Kudryavtsev empirical permafrost active layer depth model (the so-called "Ku" component). The model is specifically set up to have a basic model interface (BMI), which enhances the potential coupling to other earth surface processes model components. This model is accessible through the Web Modeling Tool in Community Surface Dynamics Modeling System (CSDMS). The Kudryavtsev model has been applied for entire Alaska to model permafrost distribution at high spatial resolution and model predictions have been verified by Circumpolar Active Layer Monitoring (CALM) in-situ observations. The Ku component uses monthly meteorological forcing, including air temperature, snow depth, and snow density, and predicts active layer thickness (ALT) and temperature on the top of permafrost (TTOP), which are important factors in snow-hydrological processes. BMI provides an easy approach to couple the models with each other. Here, we provide a case of coupling the Ku component to snow process components, including the Snow-Degree-Day (SDD) method and Snow-Energy-Balance (SEB) method, which are existing components in the hydrological model TOPOFLOW. The work flow is (1) get variables from meteorology component, set the values to snow process component, and advance the snow process component, (2) get variables from meteorology and snow component, provide these to the Ku component and advance, (3) get variables from snow process component, set the values to meteorology component, and advance the meteorology component. The next phase is to couple the permafrost component with fully BMI-compliant TOPOFLOW hydrological model, which could provide a useful tool to investigate the permafrost hydrological effect.

  4. Metagenomic analysis of a permafrost microbial community reveals a rapid response to thaw

    Science.gov (United States)

    MacKelprang, R.; Waldrop, M.P.; Deangelis, K.M.; David, M.M.; Chavarria, K.L.; Blazewicz, S.J.; Rubin, E.M.; Jansson, J.K.

    2011-01-01

    Permafrost contains an estimated 1672????????Pg carbon (C), an amount roughly equivalent to the total currently contained within land plants and the atmosphere. This reservoir of C is vulnerable to decomposition as rising global temperatures cause the permafrost to thaw. During thaw, trapped organic matter may become more accessible for microbial degradation and result in greenhouse gas emissions. Despite recent advances in the use of molecular tools to study permafrost microbial communities, their response to thaw remains unclear. Here we use deep metagenomic sequencing to determine the impact of thaw on microbial phylogenetic and functional genes, and relate these data to measurements of methane emissions. Metagenomics, the direct sequencing of DNA from the environment, allows the examination of whole biochemical pathways and associated processes, as opposed to individual pieces of the metabolic puzzle. Our metagenome analyses reveal that during transition from a frozen to a thawed state there are rapid shifts in many microbial, phylogenetic and functional gene abundances and pathways. After one week of incubation at 5 ??C, permafrost metagenomes converge to be more similar to each other than while they are frozen. We find that multiple genes involved in cycling of C and nitrogen shift rapidly during thaw. We also construct the first draft genome from a complex soil metagenome, which corresponds to a novel methanogen. Methane previously accumulated in permafrost is released during thaw and subsequently consumed by methanotrophic bacteria. Together these data point towards the importance of rapid cycling of methane and nitrogen in thawing permafrost. ?? 2011 Macmillan Publishers Limited. All rights reserved.

  5. Modelling Active Layer Changes in Permafrost Peatlands with a Topographic Wetness Index

    Science.gov (United States)

    Persson, A.; Hasan, A.; Harder, S.

    2013-12-01

    The release of methane (CH4) and other greenhouse gases from thawing permafrost has been documented in several studies. The processes behind the formation of e.g. CH4 are closely related to ground temperature and hydrology both in the thawed parts and in the permafrost zone of northern wetlands. In permafrost peatlands the thawing and freezing of the ground add to the emissions of the thawed period. The active layer thickness (ALT) and the site specific wetness are therefore important for any attempt to quantify the emissions from these peatlands. A pilot study with a modified Kudryavtsev's approach model where the ALT changes were based on a topographic wetness index (TWI) resulted in an ALT-map which show the spatial patterns of the ALT changes. In this study, a more extensive test of the model has been conducted, including active layer measurements and water level measurements over three seasons. The TWI is calculated in a high resolution, LIDAR derived, digital elevation model (DEM) for a 1.6 km2 permafrost mire complex in northern Sweden. The SSW measurements are spatially distributed around all the wetland types in the mire from surrounding fen, collapsed palsa to permafrost underlain palsa mire. Water levels are recorded bi-hourly in 40 wells. The ALT is measured from May to October at the well sites and at an additional 105 sites. The average ALT change for the palsa mire is estimated to +46 cm with a predicted change of the mean annual air temperature of +1 C. From the model and field data of ALT we can conclude that the permafrost in this mire is going to thaw out rapidly with the predicted temperature changes at high latitudes. The model sensitivity tests against field data show that the model and the use of topographic data of the mire is a tool that creates a valuable tool for the temporal ALT pattern changes.

  6. Nitrogen availability drives priming effect by altering microbial carbon-use efficiency after permafrost thaw

    Science.gov (United States)

    Chen, L.; Liu, L.; Zhang, Q.; Mao, C.; Liu, F.; Yang, Y.

    2017-12-01

    Enhanced vegetation growth can potentially aggravate soil C loss by accelerating the decomposition of soil organic matter (SOM) ("priming effect"), thereby reinforcing the positive C-climate feedback in permafrost ecosystems. However, the degree to which priming effect alters permafrost C dynamics is expected to be modified by nitrogen (N) availability after permafrost thaw. Despite this recognition, experimental evidence for the linkage between priming effect and post-thaw N availability is still lacking. Particularly, the microbial mechanisms involved remain unknown. Here, using a thermokarst-induced natural N gradient combined with an isotope-labeled glucose and N addition experiment, we presented a strong linkage between soil N availability and priming effect in Tibetan permafrost. We observed that the magnitude of priming effect along the thaw gradient was negatively associated with soil total dissolved nitrogen (TDN) concentration. This negative effect of post-thaw N availability was further proved by a sharply reduced priming effect following mineral N supply. These two lines of evidence jointly illustrated that the priming effect along the thaw chronosequence was controlled by N availability, supporting the `N mining theory'. In contrast to the prevailing assumption, this N-regulated priming effect was independent from changes in C- or N-acquiring enzyme activities, but positively associated with the change in metabolic quotients (△SOM-qCO2), highlighting that decreased microbial metabolism efficiency rather than increased enzyme activities account for greater priming effect under reduced N availability. Taken together, these findings demonstrate that C dynamics in melting permafrost largely depends on post-thaw N availability due to its effect of retarding SOM mineralization. This C-N interaction and the relevant microbial metabolic efficiency should be considered in Earth System Models for a better understanding of soil C dynamics after permafrost thaw.

  7. The subcatchment- and catchment-scale hydrology of a boreal headwater peatland complex with sporadic permafrost.

    Science.gov (United States)

    Sonnentag, O.; Helbig, M.; Connon, R.; Hould Gosselin, G.; Ryu, Y.; Karoline, W.; Hanisch, J.; Moore, T. R.; Quinton, W. L.

    2017-12-01

    The permafrost region of the Northern Hemisphere has been experiencing twice the rate of climate warming compared to the rest of the Earth, resulting in the degradation of the cryosphere. A large portion of the high-latitude boreal forests of northwestern Canada grows on low-lying organic-rich lands with relative warm and thin isolated, sporadic and discontinuous permafrost. Along this southern limit of permafrost, increasingly warmer temperatures have caused widespread permafrost thaw leading to land cover changes at unprecedented rates. A prominent change includes wetland expansion at the expense of Picea mariana (black spruce)-dominated forest due to ground surface subsidence caused by the thawing of ice-rich permafrost leading to collapsing peat plateaus. Recent conceptual advances have provided important new insights into high-latitude boreal forest hydrology. However, refined quantitative understanding of the mechanisms behind water storage and movement at subcatchment and catchment scales is needed from a water resources management perspective. Here we combine multi-year daily runoff measurements with spatially explicit estimates of evapotranspiration, modelled with the Breathing Earth System Simulator, to characterize the monthly growing season catchment scale ( 150 km2) hydrological response of a boreal headwater peatland complex with sporadic permafrost in the southern Northwest Territories. The corresponding water budget components at subcatchment scale ( 0.1 km2) were obtained from concurrent cutthroat flume runoff and eddy covariance evapotranspiration measurements. The highly significant linear relationships for runoff (r2=0.64) and evapotranspiration (r2=0.75) between subcatchment and catchment scales suggest that the mineral upland-dominated downstream portion of the catchment acts hydrologically similar to the headwater portion dominated by boreal peatland complexes. Breakpoint analysis in combination with moving window statistics on multi

  8. International student Arctic Field School on Permafrost and urban areas study

    Science.gov (United States)

    Suter, L.; Tolmanov, V. A.; Grebenets, V. I.; Streletskiy, D. A.; Shiklomanov, N. I.

    2017-12-01

    Arctic regions are experiencing drastic climatic and environmental changes. These changes are exacerbated in the Russian Arctic, where active resource development resulted in further land cover transformations, especially near large settlements. There is a growing need in multidisciplinary studies of climate and human- induced changes in the Arctic cities. In order to fill this gap, International Arctic Field Course on Permafrostand Northern Studies was organized in July 2017 to the Russian Arctic. The course was organized under the umbrella of the Arctic PIRE project in cooperation between the George Washington University, Moscow State University, and the Russian Center for Arctic Development. The course attracted twenty undergraduate and graduate students from Russia, USA, and EU countries and involved instructors specializing in Arctic system science, geocryology, permafrost engineering, and urban sustainability. The field course was focused on studying typical natural Arctic landscapes of tundra and forest tundra; transformations of natural landscapes in urban and industrial areas around Vorkuta and Salekhard; construction and planning on permafrost and field methods and techniques, including permafrost and soil temperature monitoring, active layer thickness (ALT) measurements, studying of cryogenic processes, stratigraphic and soil investigations, vegetation and microclimate studies. The students were also engaged in a discussion of climatic change and historical development of urban areas on permafrost,and were exposed to examples of both active and passive construction principles while conducting a field survey of permafrost related building deformations. During the course, students collected more than 800 ALT and soil temperature measurements in typical landscapes around Vorkuta and Salekhard to determine effects of soil and vegetation factors on ground thermal regime; surveyed several hundreds of buildings to determine locations with most deformation

  9. A nonlinear dynamical 2D coupled mathematical model for phase transitions in methane gas hydrates within permafrost under climate change

    Science.gov (United States)

    Duxbury, N. S.; Romanovsky, V. E.; Romanovskii, N. N.; Garagulya, L. S.; Brouchkov, A. V.; Komarov, I. A.; Roman, L. T.; Tipenko, G. S.; Buldovich, S. N.; Maximova, L. N.

    2012-12-01

    We have developed coupled permafrost - carbon physical and numerical models, where carbon is in the form of methane clathrate hydrate ( CH4*6H2O ) in a porous subsurface environment. The driving force for the subsurface temperature field dynamics is climate variations on the Earth's surface. This is an upper boundary condition for the nonlinear evolutionary system of partial differential equations (PDEs) describing subsurface heat transfer (parabolic PDEs) in a generalized Stefan formulation. The developed numerical model is a valuable computational tool to quantitatively study nonlinear dynamical thermal processes with phase transitions in terrestrial and Martian subsurfaces. Our model is multifrontal and therefore allows one to perform computations for a problem with any number of emerging/vanishing phase transition interfaces (both in methane gas hydrate deposits and in permafrost), since the model treats these fronts implicitly in an enthalpy formulation and in corresponding finite-difference scheme. This model takes into account the pressure (and therefore the depth) dependence of the phase transition temperature for methane clathrate hydrate. We have performed model computations using the thermophysical characteristics (heat capacity, density/porosity, thermal conductivity) for the Siberian subsurface. It can be used as a terrestrial analog for the Martian subsurface (e.g., Duxbury et al., 2001). Also, thermophysical coefficients from laboratory experiments for methane clathrate hydrate were used in our model. In addition, our model takes into account the dependence of subsurface thermophysical characteristics on temperature and spatial coordinates. The results of our computations and their interpretation will be presented. References. N. S. Duxbury, I. A. Zotikov, K. H. Nealson, V. E. Romanovsky, F. D. Carsey (2001). A numerical model for an alternative origin of Lake Vostok and its exobiological implications for Mars, Journal of Geophysical Research

  10. Long-Term Drainage Reduces CO2 Uptake and CH4 Emissions in a Siberian Permafrost Ecosystem

    Science.gov (United States)

    Kittler, Fanny; Heimann, Martin; Kolle, Olaf; Zimov, Nikita; Zimov, Sergei; Göckede, Mathias

    2017-12-01

    Permafrost landscapes in northern high latitudes with their massive organic carbon stocks are an important, poorly known, component of the global carbon cycle. However, in light of future Arctic warming, the sustainability of these carbon pools is uncertain. To a large part, this is due to a limited understanding of the carbon cycle processes because of sparse observations in Arctic permafrost ecosystems. Here we present an eddy covariance data set covering more than 3 years of continuous CO2 and CH4 flux observations within a moist tussock tundra ecosystem near Chersky in north-eastern Siberia. Through parallel observations of a disturbed (drained) area and a control area nearby, we aim to evaluate the long-term effects of a persistently lowered water table on the net vertical carbon exchange budgets and the dominating biogeochemical mechanisms. Persistently drier soils trigger systematic shifts in the tundra ecosystem carbon cycle patterns. Both, uptake rates of CO2 and emissions of CH4 decreased. Year-round measurements emphasize the importance of the non-growing season—in particular the "zero-curtain" period in the fall—to the annual budget. Approximately 60% of the CO2 uptake in the growing season is lost during the cold seasons, while CH4 emissions during the non-growing season account for 30% of the annual budget. Year-to-year variability in temperature conditions during the late growing season was identified as the primary control of the interannual variability observed in the CO2 and CH4 fluxes.

  11. Dissolved organic carbon and nitrogen release from Holocene permafrost and seasonally frozen soils

    Science.gov (United States)

    Wickland, K.; Waldrop, M. P.; Koch, J. C.; Jorgenson, T.; Striegl, R. G.

    2017-12-01

    Permafrost (perennially frozen) soils store vast amounts of carbon (C) and nitrogen (N) that are vulnerable to mobilization to the atmosphere as greenhouse gases and to terrestrial and aquatic ecosystems as dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) upon thaw. Such releases will affect the biogeochemistry of arctic and boreal regions, yet little is known about active layer (seasonally frozen) and permafrost source variability that determines DOC and TDN mobilization. We quantified DOC and TDN leachate yields from a range of active layer and permafrost soils in Alaska varying in age and C and N content to determine potential release upon thaw. Soil cores from the upper 1 meter were collected in late winter, when soils were frozen, from three locations representing a range in geographic position, landscape setting, permafrost depth, and soil types across interior Alaska. Two 15 cm-thick segments were extracted from each core: a deep active-layer horizon and a shallow permafrost horizon. Soils were thawed and leached for DOC and TDN yields, dissolved organic matter optical properties, and DOC biodegradability; soils were analyzed for C and N content, and radiocarbon content. Soils had wide-ranging C and N content (<1-44% C, <0.1-2.3% N), and varied in radiocarbon age from 450-9200 years before present - thus capturing typical ranges of boreal and arctic soils. Soil DOC and TDN yields increased linearly with soil C and N content, and decreased with increasing radiocarbon age. However, across all sites DOC and TDN yields were significantly greater from permafrost soils (0.387 ± 0.324 mg DOC g-1 soil; 0.271 ± 0.0271 mg N g-1 soil) than from active layer soils (0.210 ± 0.192 mg DOC g-1 soil; 0.00716 ± 0.00569 mg N g-1 soil). DOC biodegradability increased with increasing radiocarbon age, and was statistically similar for active layer and permafrost soils. Our findings suggest that the continuously frozen state of permafrost soils has preserved

  12. Microbial communities of the deep unfrozen: Do microbes in taliks increase permafrost carbon vulnerability? (Invited)

    Science.gov (United States)

    Waldrop, M. P.; Blazewicz, S.; Jones, M.; Mcfarland, J. W.; Harden, J. W.; Euskirchen, E. S.; Turetsky, M.; Hultman, J.; Jansson, J.

    2013-12-01

    The vast frozen terrain of northern latitude ecosystems is typically thought of as being nearly biologically inert for the winter period. Yet deep within the frozen ground of northern latitude soils reside microbial communities that can remain active during the winter months. As we have shown previously, microbial communities may remain active in permafrost soils just below the freezing point of water. Though perhaps more importantly, microbial communities persist in unfrozen areas of water, soil, and sediment beneath water bodies the entire year. Microbial activity in taliks may have significant impacts on biogeochemical cycling in northern latitude ecosystems because their activity is not limited by the winter months. Here we present compositional and functional data, including long term incubation data, for microbial communities within permafrost landscapes, in permafrost and taliks, and the implications of these activities on permafrost carbon decomposition and the flux of CO2 and CH4. Our experiment was conducted at the Alaska Peatland Experiment (APEX) within the Bonanza Creek LTER in interior Alaska. Our site consists of a black spruce forest on permafrost that has degraded into thermokarst bogs at various times over the last five hundred years. We assume the parent substrate of the deep (1-1.5m) thermokarst peat was similar to the nearby forest soil and permafrost C before thaw. At this site, flux tower and autochamber data show that the thermokarst bog is a sink of CO2 , but a significant source of CH4. Yet this does not tell the whole story as these data do not fully capture microbial activity within the deep unfrozen talik layer. There is published evidence that within thermokarst bogs, relatively rapid decomposition of old forest floor material may be occurring. There are several possible mechanisms for this pattern; one possible mechanism for accelerated decomposition is the overwintering activities of microbial communities in taliks of thermokarst

  13. Organic carbon biolabilty increases with depth in a yedoma permafrost profile in Interior Alaska

    Science.gov (United States)

    Heslop, J. K.; Walter Anthony, K. M.; Spencer, R.; Winkel, M.; Zhang, M.; Liebner, S.; Podgorski, D. C.; Zito, P.; Kholodov, A. L.

    2017-12-01

    Permafrost organic carbon (OC) biolability is known to be controlled by both the OC molecular composition and redox state and the microbial community structure and its response to permafrost thaw. However, due to their complexity, both these mechanisms remain poorly understood. A substantial portion ( 16%) of global permafrost OC is stored in particularly deep, ice-rich permafrost deposits known as yedoma. We anaerobically incubated sediment from four depths in a 12-m yedoma profile in Interior Alaska with three treatments: control without amendment, inoculated with sediment from an adjacent thermokarst lake, and inoculated with sterilized lake sediment. We quantified CO2 and CH4 as end products of C mineralization, used qPCR to characterize the initial methanogenic communities, and used FT-ICR-MS to characterize the molecular composition of water-extractable organic matter at the beginning and end of the 154-d incubation. Proportions of aliphatics and peptides increased with depth in the permafrost profile, which would be consistent with long-term accumulation of anaerobic fermentation end products in yedoma-type permafrost. Moreover, these compounds positively correlated with anaerobic CO2 and CH4 production and their degradation rates corresponded to high proportions (53.3 ±41.9%) of OC mineralization, suggesting increasing proportions of these compounds with depth correspond to increasing OC quality and increased C mineralization per unit OC. Methanogenic communities were below detection limits in all controls. Following exposure to modern lake sediment microbial communities with detectable methanogens, we observed increases in anaerobic CO2 (65.1% ±75.2%) and CH4 (1,197% ±914%) production. The treatments with sterilized lake sediment did not contain detectable methanogens, and had increased anaerobic CO2 (52.6% ±69.2%) production but decreased CH4 (-74.1% ±33.8%) production. These preliminary results suggest anaerobic CH4 production is limited by ancient

  14. Influences of Climate Warming and Facility Management on Continuous Permafrost at Matterhorn Glacier Paradise, Zermatt, Swiss Alps.

    Science.gov (United States)

    King, Lorenz; Duishonakunov, Murataly; Imbery, Stephan

    2014-05-01

    In many parts of the Alps, hazardous bedrock instabilities occur more often during the past 30 years. In many cases, permafrost degradation played a central role for instability (e.g. in 1987 the Val Pola rockslide, Italy). At other events, the role of permafrost degradation is more complex or unpredictable (e.g. in 1991 the Randa rockfall, Wallis, Swiss Alps). However, instabilities in perennially frozen bedrock may also be provoked by human influence. This is exemplarily shown at touristic facilities in the Alps. Human impact on permafrost is often underestimated, or even carelessly taken into account. The tourist resort Zermatt with more than 1.8 million overnight stays per year is located at 1600 m a.s.l. and is surrounded by high mountain ranges that often reach above 4000 m. The dry and sunny climate results in a high glacier equilibrium line thus leaving space for vast non-glaciated permafrost terrain. Numerous tourist facilities provide excellent logistics and easy access to permafrost sites, and the region is thus especially suitable for permafrost research. The infrastructure erected on permafrost consists of hotels, restaurants and mountain huts, station buildings of railways, funiculars, ski lifts and installations for artificial snowing the ski-runs. Some problems at these constructions due to permafrost degradation are shown. At the Matterhorn Glacier Paradise station at an altitude of 3820 meters, todays MAAT ranges between -6 °C and -8°C. During the construction of a tunnel in 1981 bedrock temperatures were at -12°C. Over the past 30 years, these bedrock temperatures have risen to -3 to -2°C, due to the heat brought into the tunnel by facilities and more than 490,000 visitors per year. In an elevator shaft, the temperature temporarily even rose above freezing point. Several new construction sites in continuous permafrost are described and new research data is presented. Another interesting site for permafrost and ice studies at Matterhorn

  15. The GTN-P Data Management System: A central database for permafrost monitoring parameters of the Global Terrestrial Network for Permafrost (GTN-P) and beyond

    Science.gov (United States)

    Lanckman, Jean-Pierre; Elger, Kirsten; Karlsson, Ævar Karl; Johannsson, Halldór; Lantuit, Hugues

    2013-04-01

    Permafrost is a direct indicator of climate change and has been identified as Essential Climate Variable (ECV) by the global observing community. The monitoring of permafrost temperatures, active-layer thicknesses and other parameters has been performed for several decades already, but it was brought together within the Global Terrestrial Network for Permafrost (GTN-P) in the 1990's only, including the development of measurement protocols to provide standardized data. GTN-P is the primary international observing network for permafrost sponsored by the Global Climate Observing System (GCOS) and the Global Terrestrial Observing System (GTOS), and managed by the International Permafrost Association (IPA). All GTN-P data was outfitted with an "open data policy" with free data access via the World Wide Web. The existing data, however, is far from being homogeneous: it is not yet optimized for databases, there is no framework for data reporting or archival and data documentation is incomplete. As a result, and despite the utmost relevance of permafrost in the Earth's climate system, the data has not been used by as many researchers as intended by the initiators of the programs. While the monitoring of many other ECVs has been tackled by organized international networks (e.g. FLUXNET), there is still no central database for all permafrost-related parameters. The European Union project PAGE21 created opportunities to develop this central database for permafrost monitoring parameters of GTN-P during the duration of the project and beyond. The database aims to be the one location where the researcher can find data, metadata, and information of all relevant parameters for a specific site. Each component of the Data Management System (DMS), including parameters, data levels and metadata formats were developed in cooperation with the GTN-P and the IPA. The general framework of the GTN-P DMS is based on an object oriented model (OOM), open for as many parameters as possible, and

  16. Mercury's Crater-Hosted Hollows: Chalcogenide Pryo-Thermokarst, and Permafrost Analogs on Earth, Mars, and Titan

    Science.gov (United States)

    Kargel, Jeffrey

    2013-04-01

    MESSENGER has acquired stunning images of pitted, light-toned and variegated light/dark terrains located primarily on the floors—probably impact-melt sheets—of many of Mercury's large craters. Termed "hollows", the pitted terrains are geomorphologically similar to some on Mars formed by sublimation of ice-rich permafrost and to lowland thermokarst on Earth formed by permafrost thaw; to "swiss cheese" terrain forming by sublimation of frozen CO2 at the Martian South Pole; and to suspected hydrocarbon thermokarst at Titan's poles. I shall briefly review some analogs on these other worlds. The most plausible explanation for Mercury's hollows is terrain degradation involving melting or sublimation of heterogeneous chalcogenide and sulfosalt mineral assemblages. I refer to these Mercurian features as pyrothermokarst; the etymological redundancy distinguishes the conditions and mineral agents from the ice-related features on Earth and Mars, though some of the physical processes may be similar. Whereas ice and sulfur have long been suspected and ice recently was discovered in permanently shadowed craters of Mercury's polar regions, the hollows occur down to the equator, where neither ice nor sulfur is plausible. The responsible volatiles must be only slightly volatile on the surface and/or in the upper crust of Mercury's low to middle latitudes at 400-800 K, but they must be capable of either melting or sublimating on geologically long time scales. Under prevailing upper crustal and surface temperatures, chalcophile-rich "permafrost" can undergo either desulfidation or melting reactions that could cause migration or volume changes of the permafrost, and hence lead to collapse and pitting. I propose the initial emplacement of crater-hosted chalcogenides, sulfosalts and related chalcophile materials such as pnictides, in impact-melt pools (involving solid-liquid and silicate-sulfide fractionation) and further differentiation by associated dry or humid fumaroles (solid

  17. ISR mining of uranium in the permafrost zone, Khiagda Mine (Russian Federation)

    International Nuclear Information System (INIS)

    Solodov, I.

    2014-01-01

    The “Khiagda” mine in the Republic of Buryatia is the only ISR mine in the world where ore mining is performed in a permafrost region. Its raw material source is deposits of the Khiagdinsky ore field having geological reserves of uranium to 48 thousand tonnes. The ore field is a part of the Vitimsky Uranium ore district with reserves of 100 thousand tonnes. This is the most promising region in Russia where the deposits may be extracted by the ISR technique. Throughout a year, the air temperatures varies from +35 to –50°C. Permafrost is developed everywhere to a depth of 90 m. The Khiagdinsky ore field includes 8 deposits. The ore-bearing paleovalleys down-cut the slopes of the granite rise. The ore accumulations are localised in alluvial sandy water-saturated Miocene deposits overlaying the crust formations of the granite basement. They are overlapped by the cover of basalts and volcanogenic sedimentary deposits. The ore accumulations occurrence under the cover of frozen basalts at the depths 90 to 280 m. Uranium in ores is presented by ningyoite; it is significantly reduced, comprising up to 90-100% U(IV). Mining of such ores by the acidic ISR without an oxidant is of low effectiveness. The orebearing sands are quartz-feldspar and practically noncalcareous. The acid consumption caused by chlorites and montmorillonites is at the medium level, 90 kg/tonne. The ore-bearing deposits, according to the filtration tests, have the filtration coefficient (hydraulic conductivity) of 2.1 (1.4–3.7) m/day and water transmissivity of 50 (24–105) m 2 /day. The accumulations are inundated irregularly. In the lower reaches of the paleovalleys, the output of the pumping-out wells varies from 5 to 9 m 3 /hour, and in the upper reaches it ranges from 2 to 5 m 3 /hour. The temperature of the formation waters is 1 to 4°C. The rigorous climatic conditions, high degree of uranium reduction in ores, complicated hydrogeological conditions and high viscosity of the very cold

  18. Baseline characteristics of climate, permafrost and land cover from a new permafrost observatory in the Lena River Delta, Siberia (1998–2011

    Directory of Open Access Journals (Sweden)

    J. Boike

    2013-03-01

    Full Text Available Samoylov Island is centrally located within the Lena River Delta at 72° N, 126° E and lies within the Siberian zone of continuous permafrost. The landscape on Samoylov Island consists mainly of late Holocene river terraces with polygonal tundra, ponds and lakes, and an active floodplain. The island has been the focus of numerous multidisciplinary studies since 1993, which have focused on climate, land cover, ecology, hydrology, permafrost and limnology. This paper aims to provide a framework for future studies by describing the characteristics of the island's meteorological parameters (temperature, radiation and snow cover, soil temperature, and soil moisture. The land surface characteristics have been described using high resolution aerial images in combination with data from ground-based observations. Of note is that deeper permafrost temperatures have increased between 0.3 to 1.3 °C over the last five years. However, no clear warming of air and active layer temperatures is detected since 1998, though winter air temperatures during recent years have not been as cold as in earlier years. Data related to this article are archived under: http://doi. pangaea.de/10.1594/PANGAEA.806233 .

  19. Capturing temporal and spatial variability in the chemistry of shallow permafrost ponds

    Science.gov (United States)

    Morison, Matthew Q.; Macrae, Merrin L.; Petrone, Richard M.; Fishback, LeeAnn

    2017-12-01

    Across the circumpolar north, the fate of small freshwater ponds and lakes (exchange carbon and energy with the atmosphere, and their potential to inform researchers about past climates through sediment records. A changing climate has implications for the capacity of ponds and lakes to support organisms and store carbon, which in turn has important feedbacks to climate change. Thus, an improved understanding of pond biogeochemistry is needed. To characterize spatial and temporal patterns in water column chemistry, a suite of tundra ponds were examined to answer the following research questions: (1) does temporal variability exceed spatial variability? (2) If temporal variability exists, do all ponds (or groups of ponds) behave in a similar temporal pattern, linked to seasonal hydrologic drivers or precipitation events? Six shallow ponds located in the Hudson Bay Lowlands region were monitored between May and October 2015 (inclusive, spanning the entire open-water period). The ponds span a range of biophysical conditions including pond area, perimeter, depth, and shoreline development. Water samples were collected regularly, both bimonthly over the ice-free season and intensively during and following a large summer storm event. Samples were analysed for nitrogen speciation (NO3-, NH4+, dissolved organic nitrogen) and major ions (Cl-, SO42-, K+, Ca2+, Mg2+, Na+). Across all ponds, temporal variability (across the season and within a single rain event) exceeded spatial variability (variation among ponds) in concentrations of several major species (Cl-, SO42-, K+, Ca2+, Na+). Evapoconcentration and dilution of pond water with precipitation and runoff inputs were the dominant processes influencing a set of chemical species which are hydrologically driven (Cl-, Na+, K+, Mg2+, dissolved organic nitrogen), whereas the dissolved inorganic nitrogen species were likely mediated by processes within ponds. This work demonstrates the importance of understanding hydrologically

  20. Use of Airborne Electromagnetic Geophysical Survey to Map Discontinuous Permafrost in Goldstream Valley, Interior Alaska

    Science.gov (United States)

    Daanen, R. P.; Emond, A.; Liljedahl, A. K.; Walter Anthony, K. M.; Barnes, D. L.; Romanovsky, V. E.; Graham, G.

    2016-12-01

    An airborne electromagnetic (AEM) survey was conducted in Goldstream Valley, Alaska, to map the electrical resistivity of the ground by sending a magnetic field down from a transmitter flying 30m above the ground into the subsurface. The recorded electromagnetic data are a function of the resistivity structure in the ground. The RESOLVE system used in the survey records data for six frequencies, resulting in a depth of investigation from 1-3 meters and up to 150 meters, depending on resistivity of the ground. Recording six frequencies enables the use of inversion methods to find a solution for a discretized resistivity model providing resistivity as a function of depth below ground surface. Using the airborne RESOLVE system in a populated study area involved challenges related to signal noise, access, and public opinion. Noise issues were mainly the consequence of power lines, which produce varying levels and frequencies of noise. We were not permitted to fly directly over homes, cars, animals, or people because of safety concerns, which resulted in gaps in our dataset. Public outreach well in advance of the survey informed residents about the methods used, their benefits to understanding the environment, and their potential impacts on the environment. Inversion of the data provided resistivity models that were interpreted for frozen and thawed ground conditions; these interpretation were constrained by alternate data sources such as well logs, borehole data, ground-based geophysics, and temperature measurements. The resulting permafrost map will be used to interpret groundwater movement into the valley and methane release from thermokarst lakes.

  1. ‘Bacillus massiliglaciei’, a new bacterial species isolated from Siberian permafrost

    Directory of Open Access Journals (Sweden)

    P. Afouda

    2017-01-01

    Full Text Available We describe here the main characteristics of a new species isolated from Siberian permafrost dated around 10 million years. This species was named ‘Bacillus massiliglaciei’ strain Marseille-P2600T (= CSUR P2600=DSM 102861.

  2. A study of unstable slopes in permafrost areas : Alaskan case studies used as a training tool.

    Science.gov (United States)

    2011-12-01

    This report is the companion to the PowerPoint presentation for the project A Study of Unstable Slopes in Permafrost: Alaskan Case Studies Used as a Training Tool. The objectives of this study are 1) to provide a comprehensive review of literat...

  3. Prokaryotic communities and operating metabolisms in the surface and the permafrost of Deception Island (Antarctica)

    NARCIS (Netherlands)

    Blanco, Yolanda; Prieto-Ballesteros, Olga; Gómez, Manuel J.; Moreno-Paz, Mercedes; García-Villadangos, Miriam; Rodríguez-Manfredi, José Antonio; Cruz-Gil, Patricia; Sánchez-Román, Mónica; Rivas, Luis A.; Parro, Victor

    In this study we examined the microbial community composition and operating metabolisms on the surface and in the permafrost of Deception Island, (Antarctica) with an on site antibody microarray biosensor. Samples (down to a depth of 4.2m) were analysed with LDChip300 (Life Detector Chip), an

  4. Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge thaw

    Science.gov (United States)

    Vonk, J. E.; Mann, P. J.; Dowdy, K. L.; Davydova, A.; Davydov, S. P.; Zimov, N.; Spencer, R. G. M.; Bulygina, E. B.; Eglinton, T. I.; Holmes, R. M.

    2013-09-01

    Pleistocene Yedoma permafrost contains nearly a third of all organic matter (OM) stored in circum-arctic permafrost and is characterized by the presence of massive ice wedges. Due to its rapid formation by sediment accumulation and subsequent frozen storage, Yedoma OM is relatively well preserved and highly biologically available (biolabile) upon thaw. A better understanding of the processes regulating Yedoma degradation is important to improve estimates of the response and magnitude of permafrost carbon feedbacks to climate warming. In this study, we examine the composition of ice wedges and the influence of ice wedge thaw on the biolability of Yedoma OM. Incubation assays were used to assess OM biolability, fluorescence spectroscopy to characterize the OM composition, and potential enzyme activity rates to examine the controls and regulation of OM degradation. We show that increasing amounts of ice wedge melt water in Yedoma-leached incubations enhanced the loss of dissolved OM over time. This may be attributed to the presence of low-molecular weight compounds and low initial phenolic content in the OM of ice wedges, providing a readily available substrate that promotes the degradation of Yedoma OC. The physical vulnerability of ice wedges upon thaw (causing irreversible collapse), combined with the composition of ice wedge-engrained OM (co-metabolizing old OM), underlines the particularly strong potential of Yedoma to generate a positive feedback to climate warming relative to other forms of non-ice wedge permafrost.

  5. Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

    Science.gov (United States)

    Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben; Crump, Alex R.; Chen, Xingyuan; Hess, Nancy

    2017-09-01

    Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but only in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Combining such an approach with broader knowledge of thresholding behavior - here related to active layer depth - would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.

  6. Isolation of nucleic acids and cultures from fossil ice and permafrost

    DEFF Research Database (Denmark)

    Willerslev, E.; Hansen, Anders J.; Poinar, H. N.

    2004-01-01

    Owing to their constant low temperatures, glacial ice and permafrost might contain the oldest nucleic acids and microbial cells on Earth, which could prove key to reconstructing past ecosystems and for the planning of missions to other planets. However, recent claims concerning viable cells and m...

  7. Mapping of permafrost surface using ground-penetrating radar at Kangerlussuaq Airport, western Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Andreasen, Frank

    2007-01-01

    Kangerlussuaq Airport is located at 67°N and 51°W in the zone of continuous permafrost in western Greenland. Its proximity to the Greenlandic ice sheet results in a dry sub-arctic climate with a mean annual temperature of −5.7 °C. The airport is built on a river terrace mostly consisting of fluvial...

  8. Interaction of thermal and mechanical processes in steep permafrost rock walls: A conceptual approach

    Science.gov (United States)

    Draebing, D.; Krautblatter, M.; Dikau, R.

    2014-12-01

    Degradation of permafrost rock wall decreases stability and can initiate rock slope instability of all magnitudes. Rock instability is controlled by the balance of shear forces and shear resistances. The sensitivity of slope stability to warming results from a complex interplay of shear forces and resistances. Conductive, convective and advective heat transport processes act to warm, degrade and thaw permafrost in rock walls. On a seasonal scale, snow cover changes are a poorly understood key control of the timing and extent of thawing and permafrost degradation. We identified two potential critical time windows where shear forces might exceed shear resistances of the rock. In early summer combined hydrostatic and cryostatic pressure can cause a peak in shear force exceeding high frozen shear resistance and in autumn fast increasing shear forces can exceed slower increasing shear resistance. On a multiannual system scale, shear resistances change from predominantly rock-mechanically to ice-mechanically controlled. Progressive rock bridge failure results in an increase of sensitivity to warming. Climate change alters snow cover and duration and, hereby, thermal and mechanical processes in the rock wall. Amplified thawing of permafrost will result in higher rock slope instability and rock fall activity. We present a holistic conceptual approach connecting thermal and mechanical processes, validate parts of the model with geophysical and kinematic data and develop future scenarios to enhance understanding on system scale.

  9. Numerical modelling of permafrost in bedrock in northern Fennoscandia during the Holocene

    Czech Academy of Sciences Publication Activity Database

    Kukkonen, I. T.; Šafanda, Jan

    2001-01-01

    Roč. 29, 3/4 (2001), s. 259-273 ISSN 0921-8181 Institutional research plan: CEZ:AV0Z3012916 Keywords : permafrost * Holocene * climate change * freezing * thawing * Fennoscandia Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.381, year: 2001

  10. Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

    Directory of Open Access Journals (Sweden)

    B. Mewes

    2017-12-01

    Full Text Available Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity. Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

  11. Increased plant productivity in Alaskan tundra as a result of experimental warming of soil and permafrost

    Science.gov (United States)

    S.M. Natali; E.A.G. Schuur; R.L. Rubin

    2012-01-01

    The response of northern tundra plant communities to warming temperatures is of critical concern because permafrost ecosystems play a key role in global carbon (C) storage, and climate-induced ecological shifts in the plant community will affect the transfer of carbon-dioxide between biological and atmospheric pools. This study, which focuses on the response of tundra...

  12. Utilization of ancient permafrost carbon in headwaters of Arctic fluvial networks

    NARCIS (Netherlands)

    Mann, Paul J.; Eglinton, Timothy I.; McIntyre, Cameron P.; Zimov, Nikita; Davydova, Anna; Vonk, Jorien E.; Holmes, Robert M.; Spencer, Robert G M

    2015-01-01

    Northern high-latitude rivers are major conduits of carbon from land to coastal seas and the Arctic Ocean. Arctic warming is promoting terrestrial permafrost thaw and shifting hydrologic flowpaths, leading to fluvial mobilization of ancient carbon stores. Here we describe 14 C and 13 C

  13. Multi-omics of permafrost, active layer and thermokarst bog soil microbiomes

    DEFF Research Database (Denmark)

    Hultman, Jenni; Waldrop, Mark P.; Mackelprang, Rachel

    2015-01-01

    Over 20% of Earth's terrestrial surface is underlain by permafrost with vast stores of carbon that, once thawed, may represent the largest future transfer of carbon from the biosphere to the atmosphere(1). This process is largely dependent on microbial responses, but we know little about microbia...

  14. Thermal state of permafrost in North America: a contribution to the international polar year

    Science.gov (United States)

    S.L. Smith; V.E. Romanovsky; A.G. Lewkowicz; C.R. Burn; M. Allard; G.D. Clow; K. Yoshikawa; J. Throop

    2010-01-01

    A snapshot of the thermal state of permafrost in northern North America during the International Polar Year (IPY) was developed using ground temperature data collected from 350 boreholes. More than half these were established during IPY to enhance the network in sparsely monitored regions. The measurement sites span a diverse range of ecoclimatic and geological...

  15. Effects of experimental warming of air, soil and permafrost on carbon balance in Alaskan tundra

    Science.gov (United States)

    S.M. Natali; E.A.G. Schuur; C. Trucco; C.E. Hicks Pries; K.G. Crummer; A.F. Baron Lopez

    2011-01-01

    The carbon (C) storage capacity of northern latitude ecosystems may diminish as warming air temperatures increase permafrost thaw and stimulate decomposition of previously frozen soil organic C. However, warming may also enhance plant growth so that photosynthetic carbon dioxide (C02) uptake may, in part, offset respiratory losses. To determine...

  16. Alaskan permafrost groundwater storage changes derived from GRACE and ground measurements

    Science.gov (United States)

    Reginald R. Muskett; Vladimir E. Romanovsky

    2011-01-01

    The Arctic is in transition from climate-driven thawing of permafrost. We investigate satellite-derived water equivalent mass changes, snow water equivalent with in situ measurements of runoff and ground-survey derived geoid models from 1999 through 2009. The Alaskan Arctic coastal plain groundwater storage (including wetland bog, thaw pond and lake) is increasing by 1...

  17. Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate

    Science.gov (United States)

    Arp, Christopher D.; Jones, Benjamin M.; Grosse, Guido; Bondurant, Allen C.; Romanovksy, Vladimir E.; Hinkel, Kenneth M.; Parsekian, Andrew D.

    2016-01-01

    Interactions and feedbacks between abundant surface waters and permafrost fundamentally shape lowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceeds lake depth and mean annual bed temperatures (MABTs) remain below freezing. However, declining MIT since the 1970s is likely causing talik development below shallow lakes. Here we show high-temperature sensitivity to winter ice growth at the water-sediment interface of shallow lakes based on year-round lake sensor data. Empirical model experiments suggest that shallow (1 m depth) lakes have warmed substantially over the last 30 years (2.4°C), with MABT above freezing 5 of the last 7 years. This is in comparison to slower rates of warming in deeper (3 m) lakes (0.9°C), with already well-developed taliks. Our findings indicate that permafrost below shallow lakes has already begun crossing a critical thawing threshold approximately 70 years prior to predicted terrestrial permafrost thaw in northern Alaska.

  18. Developing a mechanistically consistent picture of permafrost influence on hydrologic response (Invited)

    Science.gov (United States)

    Lyon, S. W.

    2013-12-01

    In regions experiencing permafrost thaw, catchment structure is a dynamic factor mediating hydrologic response. Predicting how this mediation will manifest is difficult since there are myriad potential hydrologic consequences from thawing permafrost such as changes to the connectivity of the aquifer system and the amount of water available for groundwater storage. For example, despite similar climate evolution and permafrost degradation over the past century, contrasting trends can be seen in the magnitude and timing of flood peaks and the mean summer discharge regionally across northern Sweden. Complementing hydrological change information with observations and detailed modeling provides a more mechanistically consistent picture of the hydrologic response impacts due to thawing permafrost. This is particularly relevant with regards to the timing of water flows that control the cycling of Carbon and other biogeochemicals within subarctic environments. As such, there is a clear added value in considering coupled process-functional changes in complement to the absolute hydrologic changes that integrate and, thus, may mask subsystem shifts in hydrologic responses (amount and timing).

  19. Models of talik, permafrost and gas hydrate histories - Beaufort Mackenzie Basin, Canada

    Czech Academy of Sciences Publication Activity Database

    Majorowicz, J.; Osadetz, K.; Šafanda, Jan

    2015-01-01

    Roč. 8, č. 7 (2015), s. 6738-6764 ISSN 1996-1073 Institutional support: RVO:67985530 Keywords : gas hydrates * permafrost * Beaufort-Mackenzie Basin * taliks Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.077, year: 2015

  20. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire

    DEFF Research Database (Denmark)

    Abbott, Benjamin W.; Jones, Jeremy B.; Schuur, Edward A. G.

    2016-01-01

    As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust esti...

  1. Permafrost collapse after shrub removal shifts tundra ecosystem into methane source

    NARCIS (Netherlands)

    Nauta, A.L.; Heijmans, M.M.P.D.; Blok, D.; Limpens, J.; Elberling, B.; Gallagher, A.; Li, B.; Petrov, R.E.; Maximov, T.C.; van Huissteden, J.; Berendse, F.

    2015-01-01

    Arctic tundra ecosystems are warming almost twice as fast as the global average. Permafrost thaw and the resulting release of greenhouse gases from decomposing soil organic carbon have the potential to accelerate climate warming. In recent decades, Arctic tundra ecosystems have changed rapidly,

  2. Permafrost collapse after shrub removal shifts tundra ecosystem to a methane source

    NARCIS (Netherlands)

    Nauta, A.L.; Heijmans, M.M.P.D.; Blok, D.; Limpens, J.; Elberling, B.; Gallagher, A.; Li, B.; Petrov, R.E.; Maximov, T.C.; Huissteden, van J.; Berendse, F.

    2015-01-01

    Arctic tundra ecosystems are warming almost twice as fast as the global average1. Permafrost thaw and the resulting release of greenhouse gases from decomposing soil organic carbon have the potential to accelerate climate warming2, 3. In recent decades, Arctic tundra ecosystems have changed

  3. Uranium isotopes and dissolved organic carbon in loess permafrost: Modeling the age of ancient ice

    Science.gov (United States)

    Ewing, Stephanie A.; Paces, James B.; O'Donnell, J.A.; Jorgenson, M.T.; Kanevskiy, M.Z.; Aiken, George R.; Shur, Y.; Harden, Jennifer W.; Striegl, Robert G.

    2015-01-01

    The residence time of ice in permafrost is an indicator of past climate history, and of the resilience and vulnerability of high-latitude ecosystems to global change. Development of geochemical indicators of ground-ice residence times in permafrost will advance understanding of the circumstances and evidence of permafrost formation, preservation, and thaw in response to climate warming and other disturbance. We used uranium isotopes to evaluate the residence time of segregated ground ice from ice-rich loess permafrost cores in central Alaska. Activity ratios of 234U vs. 238U (234U/238U) in water from thawed core sections ranged between 1.163 and 1.904 due to contact of ice and associated liquid water with mineral surfaces over time. Measured (234U/238U) values in ground ice showed an overall increase with depth in a series of five neighboring cores up to 21 m deep. This is consistent with increasing residence time of ice with depth as a result of accumulation of loess over time, as well as characteristic ice morphologies, high segregated ice content, and wedge ice, all of which support an interpretation of syngenetic permafrost formation associated with loess deposition. At the same time, stratigraphic evidence indicates some past sediment redistribution and possibly shallow thaw among cores, with local mixing of aged thaw waters. Using measures of surface area and a leaching experiment to determine U distribution, a geometric model of (234U/238U) evolution suggests mean ages of up to ∼200 ky BP in the deepest core, with estimated uncertainties of up to an order of magnitude. Evidence of secondary coatings on loess grains with elevated (234U/238U) values and U concentrations suggests that refinement of the geometric model to account for weathering processes is needed to reduce uncertainty. We suggest that in this area of deep ice-rich loess permafrost, ice bodies have been preserved from the last glacial period (10–100 ky BP), despite subsequent

  4. Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

    Science.gov (United States)

    Vonk, J. E.; Tank, S. E.; Bowden, W. B.; Laurion, I.; Vincent, W. F.; Alekseychik, P.; Amyot, M.; Billet, M. F.; Canário, J.; Cory, R. M.; Deshpande, B. N.; Helbig, M.; Jammet, M.; Karlsson, J.; Larouche, J.; MacMillan, G.; Rautio, M.; Anthony, K. M. Walter; Wickland, K. P.

    2015-12-01

    The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new freshwater ecosystems, while at the same time modifying the existing lakes, streams, and rivers that are impacted by thaw. Here, we describe the current state of knowledge regarding how permafrost thaw affects lentic (still) and lotic (moving) systems, exploring the effects of both thermokarst (thawing and collapse of ice-rich permafrost) and deepening of the active layer (the surface soil layer that thaws and refreezes each year). Within thermokarst, we further differentiate between the effects of thermokarst in lowland areas vs. that on hillslopes. For almost all of the processes that we explore, the effects of thaw vary regionally, and between lake and stream systems. Much of this regional variation is caused by differences in ground ice content, topography, soil type, and permafrost coverage. Together, these modifying factors determine (i) the degree to which permafrost thaw manifests as thermokarst, (ii) whether thermokarst leads to slumping or the formation of thermokarst lakes, and (iii) the manner in which constituent delivery to freshwater systems is altered by thaw. Differences in thaw-enabled constituent delivery can be considerable, with these modifying factors determining, for example, the balance between delivery of particulate vs. dissolved constituents, and inorganic vs. organic materials. Changes in the composition of thaw-impacted waters, coupled with changes in lake morphology, can strongly affect the physical and optical properties of thermokarst lakes. The ecology of thaw-impacted lakes and streams is also likely to change; these systems have unique microbiological communities, and show differences in respiration, primary production, and food web structure that are largely driven by differences in sediment, dissolved organic matter, and nutrient delivery. The degree to which thaw enables the delivery

  5. Arctic ecosystem reaction on permafrost melting as a result of 40 years anthropogenic impact

    Science.gov (United States)

    Petrzhik, Nataliya; Matyshak, George; Myshonkov, Alexander; Petrov, Dmitry

    2017-04-01

    Arctic ecosystems are sensitive indicators of environmental change. The increasing of anthropogenic impact perturb the natural ecosystems balance, first of all significant changes happen in soil and vegetation. It is necessary to study the permafrost ecosystem response, as the permafrost covers the quarter of the world and more than a half of Russia. Since 1960 the oil and gas industry grows in Russia. The hydrocarbons can be transferred by pipelines only in the heated state. The main effect of construction and operation of pipeline is the heating of soil and permafrost degradation. The goal of this study was to estimate the response of landscapes and permafrost ecosystem of north of West Siberia to the cumulative action of pipelines. The main objective was to investigate the warming impact on the properties and function of the soil along the pipelines in permafrost zone. The studied object was vegetation and soil cover of the north of Western Siberia ecosystems after the action of pipelines. The areas with maximum effect of heat lines were selected by remote sensing. Ten transects of 50 meters in length with sampling points every 5 meters from pipeline to undisturbed background area were selected in three different natural zones. The soil and vegetation cover was described, sampled, active layer of soil and the power of organic horizon were measured, the hydrothermal regime of soils in a layer of 0-10 cm was measured, the emission of greenhouse gas was studied. In the laboratory, the content of labile carbon, microbial biomass carbon, basal and substrate-induced respiration were measured. The main effect of the pipelines impact is the active degradation of permafrost and changes in hydrothermal settings. From background to broken areas the following settings changing: the depth of thawing increase in 10 times; the soil temperature changes from 4 to 10,5 ° C in taiga, from 4.5 to 13,5 ° C in tundra, from 5.5 to 12 ° C in forest-tundra; the soil moisture reduces

  6. Biodegradability of dissolved organic carbon in permafrost soils and aquatic systems: a meta-analysis

    Science.gov (United States)

    Jorien E. Vonk,; Tank, Suzanne E.; Paul J. Mann,; Robert G.M. Spencer,; Treat, Claire C.; Striegl, Robert G.; Benjamin W. Abbott,; Wickland, Kimberly P.

    2015-01-01

    As Arctic regions warm and frozen soils thaw, the large organic carbon pool stored in permafrost becomes increasingly vulnerable to decomposition or transport. The transfer of newly mobilized carbon to the atmosphere and its potential influence upon climate change will largely depend on the degradability of carbon delivered to aquatic ecosystems. Dissolved organic carbon (DOC) is a key regulator of aquatic metabolism, yet knowledge of the mechanistic controls on DOC biodegradability is currently poor due to a scarcity of long-term data sets, limited spatial coverage of available data, and methodological diversity. Here, we performed parallel biodegradable DOC (BDOC) experiments at six Arctic sites (16 experiments) using a standardized incubation protocol to examine the effect of methodological differences commonly used in the literature. We also synthesized results from 14 aquatic and soil leachate BDOC studies from across the circum-arctic permafrost region to examine pan-arctic trends in BDOC.An increasing extent of permafrost across the landscape resulted in higher DOC losses in both soil and aquatic systems. We hypothesize that the unique composition of (yedoma) permafrost-derived DOC combined with limited prior microbial processing due to low soil temperature and relatively short flow path lengths and transport times, contributed to a higher overall terrestrial and freshwater DOC loss. Additionally, we found that the fraction of BDOC decreased moving down the fluvial network in continuous permafrost regions, i.e. from streams to large rivers, suggesting that highly biodegradable DOC is lost in headwater streams. We also observed a seasonal (January–December) decrease in BDOC in large streams and rivers, but saw no apparent change in smaller streams or soil leachates. We attribute this seasonal change to a combination of factors including shifts in carbon source, changing DOC residence time related to increasing thaw-depth, increasing water temperatures later

  7. Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

    Science.gov (United States)

    Vonk, J.E.; Tank, S.E.; Bowden, W.B.; Laurion, I.; Vincent, W.F.; Alekseychik, P.; Amyot, Y.; Billet, M.F.; Canario, J.; Cory, R.M.; Deshpande, B.N.; Helbig, M.; Jammet, M.; Karlsson, J.; Larouche, J.; MacMillan, G.; Rautio, Milla; Walter Anthony, K.M.; Wickland, Kimberly P.

    2015-01-01

    The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new freshwater ecosystems, while at the same time modifying the existing lakes, streams, and rivers that are impacted by thaw. Here, we describe the current state of knowledge regarding how permafrost thaw affects lentic (still) and lotic (moving) systems, exploring the effects of both thermokarst (thawing and collapse of ice-rich permafrost) and deepening of the active layer (the surface soil layer that thaws and refreezes each year). Within thermokarst, we further differentiate between the effects of thermokarst in lowland areas vs. that on hillslopes. For almost all of the processes that we explore, the effects of thaw vary regionally, and between lake and stream systems. Much of this regional variation is caused by differences in ground ice content, topography, soil type, and permafrost coverage. Together, these modifying factors determine (i) the degree to which permafrost thaw manifests as thermokarst, (ii) whether thermokarst leads to slumping or the formation of thermokarst lakes, and (iii) the manner in which constituent delivery to freshwater systems is altered by thaw. Differences in thaw-enabled constituent delivery can be considerable, with these modifying factors determining, for example, the balance between delivery of particulate vs. dissolved constituents, and inorganic vs. organic materials. Changes in the composition of thaw-impacted waters, coupled with changes in lake morphology, can strongly affect the physical and optical properties of thermokarst lakes. The ecology of thaw-impacted lakes and streams is also likely to change; these systems have unique microbiological communities, and show differences in respiration, primary production, and food web structure that are largely driven by differences in sediment, dissolved organic matter, and nutrient delivery. The degree to which thaw enables the delivery

  8. Might short term rockglacier surface morphological changes be attributed to permafrost degradation ?

    Science.gov (United States)

    Perrier, Romain; Cossart, Etienne; Fort, Monique

    2015-04-01

    In high mountain environments, permafrost is increasingly affected by climate change. Rockglaciers represent the expression of creeping permafrost: they are generally considered as good geo-indicators of cryosphere distribution and evolution. Research dealing with the effect of climate change on rockglacier degradation is mostly based on photogrammetric studies as well as geophysics. Major results on rockglaciers behavior in relation to increasing mean annual air temperature are summarized as follows. Firstly, photogrammetry analysis shows that rockglacier surface velocities are higher when the permafrost temperature and/or water content increase within the rockglacier system; this can sometimes lead to the destabilization/collapse of rockglaciers. Secondly, geophysical studies demonstrate a decrease in resistivities within the rockglacier body in relation to a decrease in ice content hence suggesting a degradation of permafrost. Although these methods are appropriate for studying the effects of climate change on mountain permafrost and rockglacier evolution, their application is fairly costly and time-consuming, and are usually restricted to one or two study cases. Our investigations over a wider area up to regional scale require completing our approach by using surface morphological changes, a method that can identify potential degradation in a warming context. In this context, this work intends to characterize short terms (multi-decades) surface morphological changes at rockglacier scale and to determine if these changes may be attributed to potential permafrost degradation. Our investigations have been carried out in both Clarée and Ubaye valleys, in the French Southern Alps. Here we present our results obtained from the Lac Rouge rockglacier (45°02'49''N, 6°30'16''E; 2600-2825m a.s.l, Clarée valley, French Southern Alps). Analysis of multi-temporal aerial photographs, geomorphological field mapping, electrical resistivity tomographies and surface

  9. Permafrost detection in the headwalls of receding glaciers at the Dachstein Massif, Northern Calcareous Alps, Austria

    Science.gov (United States)

    Rode, Matthias; Gitschthaler, Christoph; Schnepfleitner, Harald; Kellerer-Pirklbauer, Andreas; Sass, Oliver

    2014-05-01

    The Northern Calcareous Alps cover a large area of the Austrian Alps forming a boundary zone between the Alpine Foreland to the north and the crystalline Central Alps to the south. Generally, climate in this area is more maritime compared to the mountain ranges further south. Few small glaciers are to be found mostly on north-facing slopes. The Northern Calcareous Alps reach maximum elevations of about 3000 m asl. Some of highest summits are to be found are located in the Dachstein Massif reaching 2995 m asl (47° 28' 32″ N, 13° 36' 23″ E). Occurrence, thickness and thermal regime of permafrost at this mountain massif are widely unknown and knowledge is based on simulations only. In contrast, the glaciation changes at this mountain massif (e.g. Schladminger and Hallstätter glaciers) have been well documented for decades. Within the framework of the research project ROCKING ALPS - dealing with frost weathering and rockfall in alpine regions - knowledge of permafrost distribution in the headwalls surrounding the receding glaciers is substantial to understand rock decay. For this reason, several techniques have been applied in order to detect bedrock permafrost. During the winter of 2012 22 i-buttons (temperature sensors) were attached to rock walls with different orientations but at similar elevations (2600-2700 m asl). Most of these sites were later covered by an insulating winter snow cover therefore allowing the calculation of the base temperature of the winter snow cover (BTS). These BTS data have been used as a first indicator of permafrost presence. In selected rock walls of several mountains in the massif - Koppenkarstein (2863 m asl), Dirndln (2829 m asl) and Gjaidstein (2794 m asl) - additional 2D-geoelectric surveys (five ERT profiles with a length of 100 m and 2 m electrode spacing) were measured in summer 2013. The high resistivities (> 50.000 ohm.m) at about 1.5 m depth and deeper strongly suggest permafrost existence inside the bedrock at all

  10. Application of a simple first-order, non-linear rainfall-runoff model in watersheds of varying permafrost coverage

    Science.gov (United States)

    Bolton, W. Robert; Hinzman, Larry

    2010-05-01

    The arctic and sub-arctic environments can be characterized as being in the zones continuous and discontinuous permafrost. Although the distribution of permafrost in these regions is site specific, it is the major control on many of the hydrologic processes including stream flow, soil moisture dynamics, and water storage processes. In areas underlain by permafrost, ice-rich soils a the permafrost table inhibit surface water percolation to the deep subsurface soils, resulting in an increased runoff generation during precipitation events (including snow melt), decreased baseflow between precipitation events, and relatively wetter soils compared to permafrost-free areas. Over the course of a summer season, the thawing of the active layer (the thin soil layer above the permafrost that seasonally freezes and thaws) increases the potential water holding capacity of the soil, resulting in a decreasing surface water contribution during precipitation events and a steadily increasing baseflow between precipitation events. The major challenge to hydrologic modeling in permafrost affected environments is accounting for the rapid spatial and temporal changes in the soil storage component with the thawing and freezing of the active layer and distribution of permafrost. Simulation of the storage storage component is further complicated as many of the variables that control the development of the active layer (and permafrost distribution) are not easily measurable beyond the point scale. Examples of these variables include soil material, soil moisture content, soil ice content, snow cover and depth, and surface temperature. Kirchner (2009) describes a method in which the total storage of a watershed can be derived directly from discharge measurements - the only hydrologic process that is easily measured at the watershed scale. Following the general procedure outlined by Kirchner, a simple rainfall-runoff model was developed and applied to basins of various scales and permafrost

  11. Landscape controls and vertical variability of soil organic carbon storage in permafr