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  • 1. Christiansen, Hanne H.
    Report from the International Permafrost Association: High level of permafrost interdisciplinary research activity2013In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 24, no 4, p. 347-349Article in journal (Refereed)
  • 2. Galka, Mariusz
    et al.
    Szal, Marta
    Watson, Elizabeth J.
    Gallego-Sala, Angela
    Amesbury, Matthew J.
    Charman, Dan J.
    Roland, Thomas P.
    Turner, T. Edward
    Swindles, Graeme T.
    Vegetation Succession, Carbon Accumulation and Hydrological Change in Subarctic Peatlands, Abisko, Northern Sweden2017In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 28, no 4, p. 589-604Article in journal (Refereed)
    Abstract [en]

    High-resolution analyses of plant macrofossils, testate amoebae, pollen, mineral content, bulk density, and carbon and nitrogen were undertaken to examine the late Holocene dynamics of two permafrost peatlands in Abisko, Subarctic Sweden. The peat records were dated using tephrochronology, C-14 and Pb-210. Local plant succession and hydrological changes in peatlands were synchronous with climatic shifts, although autogenous plant succession towards ombrotrophic status during peatland development was also apparent. The Marooned peatland experienced a shift ca. 2250cal yr BP from rich to poor fen, as indicated by the appearance of Sphagnum fuscum. At Stordalen, a major shift to wetter conditions occurred between 500 and 250cal yr BP, probably associated with climate change during the Little Ice Age. During the last few decades, the testate amoeba data suggest a deepening of the water table and an increase in shrub pollen, coinciding with recent climate warming and the associated expansion of shrub communities across the Arctic. Rates of carbon accumulation vary greatly between the sites, illustrating the importance of local vegetation communities, hydrology and permafrost dynamics. Multiproxy data elucidate the palaeoecology of S. lindbergii and show that it indicates wet conditions in peatlands. Copyright (c) 2017 John Wiley & Sons, Ltd.

  • 3. Gisnås, Kjersti
    et al.
    Etzelmüller, Bernd
    Lussana, Cristian
    Hjort, Jan
    Sannel, A. Britta K.
    Isaksen, Ketil
    Westermann, Sebastian
    Kuhry, Peter
    Christiansen, Hanne H.
    Frampton, Andrew
    Åkerman, Jonas
    Permafrost Map for Norway, Sweden and Finland2017In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 28, no 2, p. 359-378Article in journal (Refereed)
    Abstract [en]

    A research-based understanding of permafrost distribution at a sufficient spatial resolution is important to meet the demands of science, education and society. We present a new permafrost map for Norway, Sweden and Finland that provides a more detailed and updated description of permafrost distribution in this area than previously available. We implemented the CryoGRID1 model at 1 km2 resolution, forced by a new operationally gridded data-set of daily air temperature and snow cover for Finland, Norway and Sweden. Hundred model realisations were run for each grid cell, based on statistical snow distributions, allowing for the representation of sub-grid variability of ground temperature. The new map indicates a total permafrost area (excluding palsas) of 23 400 km2 in equilibrium with the average 1981–2010 climate, corresponding to 2.2 per cent of the total land area. About 56 per cent of the area is in Norway, 35 per cent in Sweden and 9 per cent in Finland. The model results are thoroughly evaluated, both quantitatively and qualitatively, as a collaboration project including permafrost experts in the three countries. Observed ground temperatures from 25 boreholes are within ± 2 °C of the average modelled grid cell ground temperature, and all are within the range of the modelled ground temperature for the corresponding grid cell. Qualitative model evaluation by field investigators within the three countries shows that the map reproduces the observed lower altitudinal limits of mountain permafrost and the distribution of lowland permafrost. Copyright © 2016 John Wiley & Sons, Ltd.

  • 4. Gonçalo Vieira1, *
    Thermal state of permafrost and active-layer monitoring in the antarctic: Advances during the international polar year 2007–20092010In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 21, no 2, p. 182-197Article in journal (Refereed)
    Abstract [en]

    Results obtained during the International Polar Year (IPY) on the thermal state of permafrost and the active layer in the Antarctic are presented, forming part of ANTPAS (‘Antarctic Permafrost and Soils’), which was one of the key projects developed by the International Permafrost Association and the Scientific Committee for Antarctic Research for the IPY. The number of boreholes for permafrost and active-layer monitoring was increased from 21 to 73 during the IPY, while CALM-S sites to monitor the active layer were increased from 18 to 28. Permafrost temperatures during the IPY were slightly below 0°C in the South Shetlands near sea-level, showing that this area is near the climatic boundary of permafrost and has the highest sensitivity to climate change in the region. Permafrost temperatures were much lower in continental Antarctica: from the coast to the interior and with increasing elevation they ranged between −13.3°C and −18.6°C in Northern Victoria Land, from −17.4°C to −22.5°C in the McMurdo Dry Valleys, and down to −23.6°C at high elevation on Mount Fleming (Ross Island). Other monitored regions in continental Antarctica also showed cold permafrost: Queen Maud Land exhibited values down to −17.8°C on nunataks, while in Novolazarevskaya (Schirmacher Oasis) at 80 m a.s.l. the permafrost temperature was −8.3°C. The coastal stations of Molodeznaya at Enderby Land showed permafrost temperatures of −9.8°C, Larsemann Hills – Progress Station in the Vestfold Hills region – recorded −8.5°C, and Russkaya in Marie Byrd Land, −10.4°C. This snapshot obtained during the IPY shows that the range of ground temperatures in the Antarctic is greater than in the Arctic. Copyright © 2010 John Wiley & Sons, Ltd.

  • 5. Jelinski, Nicolas A.
    et al.
    Yoo, Kyungsoo
    Klaminder, Jonatan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Utilising a suite of isotopic and elemental tracers to constrain cryoturbation rates and patterns in a non-sorted circle2017In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 28, no 4, p. 634-648Article in journal (Refereed)
    Abstract [en]

    The empirical quantification of rates of material movement in cryoturbated soils has lagged behind the physical and chemical characterisation of these materials. We applied a novel suite of elemental (C, Hg), stable isotope (C-13) and radioisotope (Cs-137, Pb-210, C-14, Be-10) tracers in conjunction with analytical and numerical models to constrain the rates and patterns of soil movement due to cryoturbation in a non-sorted circle (NSC) near Abisko, Sweden. We present the first observations of the variability of Be-10 across a patterned-ground feature, which facilitate the interpretation of subsurface peaks in soil organic carbon, Hg and C-13 and provide constraints on the surficial histories of cryoturbated materials. Apparent rates of surficial lateral movement across the NSC estimated from Cs-137 and Pb-210 (0-2.55cm year(-1)) decreased with distance from its centre and were an order of magnitude greater than rates of subduction and subsurface movement estimated from C-14 (0.04-0.27cm year(-1)). Novel estimates of the original surficial residence times of cryoturbated parcels based on excess Be-10 and Hg inventories ranged from 238 to 3940years. Our results demonstrate the utility of the spatially explicit application of elemental and radioisotopic tracer suites to constrain cryoturbation rates in Arctic patterned ground.

  • 6. Klaminder, J.
    et al.
    Yoo, K.
    Olid, C.
    Ramebäck, H.
    Vesterlund, A.
    Using Short-lived Radionuclides to Estimate Rates of Soil Motion in Frost Boils2014In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 25, no 3, p. 184-193Article in journal (Refereed)
    Abstract [en]

    Cryoturbation in high-latitude soils is crucial for the long-term cycling of elements, but the rates of soil motion are poorly constrained. Here, we test whether the rate of frost creep, soil erosion and vertical soil mixing in frost boils can be estimated using short-lived radionuclides (137Cs and 210Pb). We find a small-scale variation in 137Cs and 210Pb inventories in the lower levels of the eroding regions of frost boils in comparison to the expected depositional sites; hence, the distribution of the radionuclides appears to reflect a lateral transport of atmospheric fallout from the centre of the boil (inner domain) towards the surrounding soil (outer domain). 14C dating of the soil indicates that fallout of 137Cs was mobile in the soil and that 210Pb moved with the soil matrix. A soil creep model and a surface soil erosion model are derived and applied to the lateral and vertical distributions of 210Pb in the frost boil. Both models predict the expected trajectories of soil motion and provide rates of creep, erosion and mixing at a mm yr−1 to cm yr−1 scale. The distribution of 210Pb provides new insights about the processes and rates of soil mass movement in frost boils, if sound mass-balance models are applied. Copyright © 2014 John Wiley & Sons, Ltd.

  • 7. Klaus, Marcus
    et al.
    Becher, Marina
    Klaminder, Jonatan
    Cryogenic Soil Activity along Bioclimatic Gradients in Northern Sweden: Insights from Eight Different Proxies2013In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 24, no 3, p. 210-223Article in journal (Refereed)
    Abstract [en]

    Cryogenic soil activity caused by differential soil movements during freeze-thaw cycles is of fundamental importance for Arctic ecosystem functioning, but its response to climate warming is uncertain. Eight proxies of cryogenic soil activity (including measurements of soil surface motion, vegetation and grey values of aerial photographs) were examined at eight study sites where non-sorted patterned ground spans an elevation gradient (400–1150 m asl) and a precipitation gradient (300–1000 mm yr-1) near Abisko, northern Sweden. Six proxies were significantly correlated with each other (mean |r| = 0.5). Soil surface motion increased by three to five times along the precipitation gradient and was two to four times greater at intermediate elevations than at low and high elevations, a pattern reflected by vegetation assemblages. The results suggest that inferences about how cryogenic soil activity changes with climate are independent of the choice of the proxy, although some proxies should be applied carefully. Four preferred proxies indicate that cryogenic soil activity may respond differently to climate warming along the elevation gradient and could be greatly modified by precipitation. This underlines the strong but spatially complex response of cryogenic processes to climate change in the Arctic. Copyright © 2013 John Wiley & Sons, Ltd.

  • 8. Kruger, Jan Paul
    et al.
    Conen, Franz
    Leifeld, Jens
    Alewell, Christine
    Palsa Uplift Identified by Stable Isotope Depth Profiles and Relation of N-15 to C/N Ratio2017In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 28, no 2, p. 485-492Article in journal (Refereed)
    Abstract [en]

    Palsas develop as permafrost aggradation uplifts peat out of the zone influenced by groundwater. Here we relate N-15 values to C/N ratios along depth profiles through palsas in two peatlands near Abisko, northern Sweden, to identify perturbation of the peat. The perturbation by uplift as well as the potential nutrient input from the adjacent hollows can be detected in soil N-15 values when related to the C/N ratio at the same depth. Nine out of ten profiles show a perturbation at the depth where peat was uplifted by permafrost. Palsa uplift could be detected by the N-15 depth pattern, with the highest N-15 values at the so-called turning point. The N-15 values increase above and decrease below the turning point, when permafrost initiated uplift. Onset of permafrost aggradation calculated from peat accumulation rates was between 80 and 545years ago, with a mean of 242 ( +/- 66) years for Stordalen and 365 ( +/- 53) years for Storflaket peatland. The mean ages of permafrost aggradation are within the Little Ice Age. Depth profiles of N-15, when related to C/N ratio, seem to be a suitable tool to detect perturbation and uplift of palsas. Copyright (c) 2016 John Wiley & Sons, Ltd.

  • 9. Lupascu, M.
    et al.
    Wadham, J. L.
    Hornibrook, E. R. C.
    Pancost, R. D.
    Methanogen Biomarkers in the Discontinuous Permafrost Zone of Stordalen, Sweden2014In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 25, no 4, p. 221-232Article in journal (Refereed)
    Abstract [en]

    Permafrost peatlands are both an important source of atmospheric CH4 and a substantial sink for atmospheric CO2. Climate change can affect this balance, with higher temperatures resulting in the conversion of permafrost soils to wetlands and associated accelerated mineralisation and increased CH4 emission. To better understand the impact of such processes on methanogen populations, we investigated the anaerobic decay of soil carbon in a low Arctic, discontinuous permafrost peatland. Cores were collected monthly from sedge and Sphagnum mires in north Sweden during the summer of 2006. We determined CH4 concentrations and production potentials, together with variations in the size of the methanogenic community as indicated by concentrations of archaeal lipid biomarkers (phosphorylated archaeol, archaeol and hydroxyarchaeol). Concentrations of methanogen biomarkers generally were higher at the sedge site, increased with depth for all sites and months, and were usually below the detection limits in shallow (<10cm) Sphagnum peat. The distribution of biomarkers reflects the strong influence of water table depth on anaerobic conditions and methanogen populations, while differences in biomarker concentrations can be explained by differences in vegetation cover and pH. However, methanogen populations inferred from biomarker data show a decoupling from in-situ CH4 production over the season and from CH4 production potential, suggesting that other factors such as the availability of labile organic substrates can influence methanogen abundance. Archaeal lipid biomarkers appear to offer a potential new means to investigate permafrost biogeochemical processes but the interpretation of signals remains complex. Copyright (c) 2014 John Wiley & Sons, Ltd.

  • 10.
    Ridefelt, Hanna
    et al.
    Uppsala universitet, Miljö- och landskapsdynamik.
    Boelhouwers, Jan
    Uppsala universitet, Miljö- och landskapsdynamik.
    Observations on Regional Variation in Solifluction Landform Morphology and Environment in the Abisko, northern Sweden2006In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 17, no 3, p. 253-266Article in journal (Refereed)
    Abstract [en]

    Turf-banked lobes and terraces on the valley slopes and stone-banked or non-sorted lobes at summits show a distinct regional trend of decreasing size from west to east in the Abisko region, northern Sweden. Significant correlations with environmental parameters exist between morphometry and elevation, soil moisture and soil texture. At a regional scale, high soil moisture environments can be associated with larger dimensions. The turf-banked forms in the valleys are associated with deep seasonal snow cover and therefore saturated conditions are believed to enhance gelifluction at these locations. The smaller forms on the vegetation- and snow-free summit sites are believed to be dominated by frost creep.

  • 11. Sanchez-Garcia, L.
    et al.
    Vonk, J. E.
    Charkin, A. N.
    Kosmach, D.
    Dudarev, O. V.
    Semiletov, I. P.
    Gustafsson, Ö.
    Characterisation of Three Regimes of Collapsing Arctic Ice Complex Deposits on the SE Laptev Sea Coast using Biomarkers and Dual Carbon Isotopes2014In: Permafrost and Periglacial Processes, ISSN 1045-6740, E-ISSN 1099-1530, Vol. 25Article in journal (Refereed)
    Abstract [en]

    Arctic amplification of climate warming is intensifying the thaw and coastal erosion of the widespread and carbon-rich Siberian Ice Complex Deposits (ICD). Despite the potential for altering long-term carbon dynamics in the Arctic, the susceptibility of organic carbon (OC) to degradation as the ICD thaw is poorly characterised. This study identifies signs of OC degradation in three Siberian ICD regimes of coastal erosion through elemental, isotopic and molecular analyses. The degree of erosion appears to determine the extent of degradation. The moisture-limited and beach-protected ICD bluff near Buor-Khaya Cape, characterised by thermokarst mounds (baydzherakhs), represents a dormant regime with limited ongoing degradation. Conversely, the more exposed ICD scarps on eroding riverbanks (Olenek Channel, Lena Delta) and coastal slopes (Muostakh Island) showed more pronounced signs of ongoing OC decay. Different parameters suggest that degradation can partially explain the shift of the OC signature with C-14 age in the thawing ICD. Exposure time, degree of erosion, slope gradient and moisture conditions appear to be key factors determining the degradation propensity of OC in exposed ICD. These field results document the lability of OC in ICD upon thaw and illustrate the potential for transferring old OC into the rapidly cycling atmosphere-biosphere carbon pools. Copyright (C) 2014 John Wiley & Sons, Ltd.

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