Change search
Refine search result
1 - 17 of 17
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1. Berteaux, Dominique
    et al.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Erlandsson, Rasmus
    Stockholm University, Faculty of Science, Department of Zoology.
    Norén, Karin
    Stockholm University, Faculty of Science, Department of Zoology.
    White, Paula A.
    Harmonizing circumpolar monitoring of Arctic fox: benefits, opportunities, challenges and recommendations2017In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 36, no suppl. 1, article id 2Article in journal (Refereed)
    Abstract [en]

    The biodiversity working group of the Arctic Council has developed pan-Arctic biodiversity monitoring plans to improve our ability to detect, understand and report on long-term change in Arctic biodiversity. The Arctic fox (Vulpes lagopus) was identified as a target of future monitoring because of its circumpolar distribution, ecological importance and reliance on Arctic ecosystems. We provide the first exhaustive survey of contemporary Arctic fox monitoring programmes, describing 34 projects located in eight countries. Monitored populations covered equally the four climate zones of the species’ distribution, and there were large differences between populations in long-term trends, multi-annual fluctuations, diet composition, degree of competition with red fox and human interferences. Den density, number of active dens, number of breeding dens and litter size were assessed in almost all populations, while projects varied greatly with respect to monitoring of other variables indicative of population status, ecosystem state or ecosystem function. We review the benefits, opportunities and challenges to increased integration of monitoring projects. We argue that better harmonizing protocols of data collection and data management would allow new questions to be addressed while adding tremendous value to individual projects. However, despite many opportunities, challenges remain. We offer six recommendations that represent decisive progress toward a better integration of Arctic fox monitoring projects. Further, our work serves as a template that can be used to integrate monitoring efforts of other species, thereby providing a key step for future assessments of global biodiversity.

  • 2. Berteaux, Dominique
    et al.
    Casajus, Nicolas
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Fuglei, Eva
    Foreword to Supplement 1: research on a polar species-the Arctic fox2017In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 36, article id 1Article in journal (Refereed)
    Abstract [en]

    The Arctic fox has a circumpolar distribution and is intensively studied because it is adapted to extreme environments and influences the ecology of many other species. We introduce here a collection of 12 articles on Arctic fox biology and management. After summarizing the main biological features of the species, we explore the peer-reviewed literature dealing with the Arctic fox through a bibliometric network analysis which identifies clusters of papers sharing a high similarity of cited literature. We visualize with a word cloud analysis 10 clusters comprising 97% of 755 articles published by 1742 authors from 1996-2015. Behavioural and ecological questions, including conservation science, dominate this recent literature. The collection of papers published in the supplement offers an excellent representation of current research dealing with Arctic fox biology and management.

  • 3.
    Bring, Arvid
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Hydrological and hydrochemical observation status in the pan-Arctic drainage basin2009In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 28, p. 327-338Article in journal (Refereed)
    Abstract [en]

    In order to identify and understand the ongoing changes in the Arctic hydrological cycle, and the impacts on the Arctic Ocean, timely and open access to water and water-chemistry data is essential. By synthesizing and analysing all openly accessible water-discharge and water-quality data, we present an updated, quantitative picture of the status of observational data on hydrological and hydrochemical fluxes from the pan-Arctic drainage basin (PADB) to the ocean. We identify and compare the characteristics of monitored and unmonitored areas, and the differences between them, across the continents in the PADB. Results indicate significant gaps in monitoring data for water chemistry, in particular for high-latitude near-coastal areas. The differences in characteristics between monitored and unmonitored areas may bias assessments of hydrological and hydrochemical fluxes to the Arctic Ocean. The reliable identification and understanding of important biogeochemical processes in the PADB require extended monitoring, particularly in high-latitude permafrost ground, and more ready access to harmonized and integrated hydrochemical data.

  • 4.
    Dalerum, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kunkel, K.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Shults, B. S.
    Diet of wolverines (Gulo gulo) in the western Brooks Range, Alaska2009In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 28, no 2, p. 246-253Article in journal (Refereed)
    Abstract [en]

    Migratory caribou herds are an important component of the North American tundra. We investigated the wolverine (Gulo gulo) diet in the migratory range of the Western Arctic Caribou Herd in north-western Alaska. Within this area, caribou are absent or occur at low densities for large parts of the year, and thus show a strong seasonality in abundance. Analyses of stomach and colon contents suggested that wolverines primarily consumed caribou during the winter, and that the dietary dependence was related more to caribou mortality than to caribou abundance in the area. We also found indications that wolverines may switch between moose and caribou during periods of low caribou abundance, but that such a switch did not affect wolverine body condition. Our results thus support previous observations that wolverines primarily consume ungulates. However, a better knowledge of how alternative food sources are utilized will be necessary to predict the dietary and demographic responses of wolverines to variations in caribou abundance. We also suggest that further efforts should be made to investigate the effects of other ungulate-dependent predators on wolverine feeding ecology, because such predators may function both as competitors and as suppliers of carrion for scavenging.

  • 5.
    Elmhagen, Bodil
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Berteaux, Dominique
    Burgess, Robert M.
    Ehrich, Dorothee
    Gallant, Daniel
    Henttonen, Heikki
    Ims, Rolf A.
    Killengreen, Siw T.
    Niemimaa, Jukka
    Norén, Karin
    Stockholm University, Faculty of Science, Department of Zoology.
    Ollila, Tuomo
    Rodnikova, Anna
    Sokolov, Alexandrs A.
    Sokolova, Natasha A.
    Stickney, Alica A.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Homage to Hersteinsson and Macdonald: climate warming and resource subsidies cause red fox range expansion and Arctic fox decline2017In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 36, no suppl. 1, article id 3Article, review/survey (Refereed)
    Abstract [en]

    Climate change can have a marked effect on the distribution and abundance of some species, as well as their interspecific interactions. In 1992, before ecological effects of anthropogenic climate change had developed into a topical research field, Hersteinsson and Macdonald published a seminal paper hypothesizing that the northern distribution limit of the red fox (Vulpes vulpes) is determined by food availability and ultimately climate, while the southern distribution limit of the Arctic fox (Vulpes lagopus) is determined by interspecific competition with the larger red fox. This hypothesis has inspired extensive research in several parts of the circumpolar distribution range of the Arctic fox. Over the past 25 years, it was shown that red foxes can exclude Arctic foxes from dens, space and food resources, and that red foxes kill and sometimes consume Arctic foxes. When the red fox increases to ecologically effective densities, it can cause Arctic fox decline, extirpation and range contraction, while conservation actions involving red fox culling can lead to Arctic fox recovery. Red fox advance in productive tundra, concurrent with Arctic fox retreat from this habitat, support the original hypothesis that climate warming will alter the geographical ranges of the species. However, recent studies show that anthropogenic subsidies also drive red fox advance, allowing red fox establishment north of its climate-imposed distribution limit. We conclude that synergies between anthropogenic subsidies and climate warming will speed up Arctic ecosystem change, allowing mobile species to establish and thrive in human-provided refugia, with potential spill-over effects in surrounding ecosystems.

  • 6.
    Hanslik, Daniela
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Loewemark, Ludvig
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Biogenic and detrital rich intervals in central arctic ocean cores identified using x ray fluorescence scanning2013In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 32, p. 18386-Article in journal (Refereed)
    Abstract [en]

    X-ray fluorescence (XRF) scanning of sediment cores from the Lomonosov Ridge and the Morris Jesup Rise reveals a distinct pattern of Ca intensity peaks through Marine Isotope Stages (MIS) 1 to 7. Downcore of MIS 7, the Ca signal is more irregular and near the detection limit. Virtually all major peaks in Ca coincide with a high abundance of calcareous microfossils; this is particularly conspicuous in the cores from the central Arctic Ocean. However, the recorded Ca signal is generally caused by a combination of biogenic and detrital carbonate, and in areas influenced by input from the Canadian Arctic, detrital carbonates may effectively mask the foraminiferal carbonates. Despite this, there is a strong correlation between XRF-detected Ca content and foraminiferal abundance. We propose that in the Arctic Ocean north of Greenland a common palaeoceanographic mechanism is controlling Ca-rich ice-rafted debris (IRD) and foraminiferal abundance. Previous studies have shown that glacial periods are characterized by foraminfer-barren sediments. This implies that the Ca-rich IRD intervals with abundant foraminifera were most likely deposited during interglacial periods when glaciers left in the Canadian Arctic Archipelago were still active and delivered a large amount of icebergs. At the same time, conditions were favourable for planktic foraminifera, resulting in a strong covariance between these proxies. Therefore, we suggest that the XRF scanner's capability to efficiently map Ca concentrations in sediment cores makes it possible to systematically examine large numbers of cores from different regions to investigate the palaeoceanographic reasons for the calcareous microfossils' spatial and temporal variability.

  • 7. Jonsell, Ulf
    et al.
    Hock, Regine
    Duguay, Martial
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Recent air and ground temperature increases at Tarfala Research Station, Sweden2013In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 32, no UNSP 19807Article in journal (Refereed)
    Abstract [en]

    Long-term data records are essential to detect and understand environmental change, in particular in generally data-sparse high-latitude and high-altitude regions. Here, we analyse a 47-year air temperature record (1965 2011) at Tarfala Research Station (67 degrees 54.7'N, 18 degrees 36.7'E, 1135 m a.s.l.) in northern Sweden, and a nearby 11-year record of 100-m-deep ground temperature (2001-11; 1540 m a.s.l.). The air temperature record shows a mean annual air temperature of -3.5 +/- 0.9 degrees C (+/- 1 standard deviation sigma) and a linear warming trend of +/- 0.042 degrees C yr(-1). The warming trend shows large month-to-month variations with the largest trend in January followed by October. Also, the number of days with positive mean daily temperatures and positive degree-day sums has increased during the last two decades compared to the previous period. Temperature lapse rates derived from the mean daily Tarfala record and an air temperature record at the borehole site average 4.5 degrees C km(-1) and tend to be higher in summer than in winter. Mean summer air temperatures at Tarfala explain 76% of the variance of the summer glacier mass balance of nearby Storglaciaren. Consistent with the observed increase in Tarfala's air temperature, the ground temperature record shows significant permafrost warming with the largest trend (0.047 degrees C yr(-1)) found at 20 m depth.

  • 8. Kuhnel, Rafael
    et al.
    Björkman, Mats P.
    Vega, Carmen P.
    Hodson, Andy
    Isaksson, Elisabeth
    Ström, Johan
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Reactive nitrogen and sulphate wet deposition at Zeppelin Station, Ny-Alesund, Svalbard2013In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 32Article in journal (Refereed)
    Abstract [en]

    As a potent fertilizer, reactive nitrogen plays an important role in Arctic ecosystems. Since the Arctic is a nutrient-limited environment, changes in nitrogen deposition can have severe impacts on local ecosystems. To quantify the amount of nitrogen deposited through snow and rain events, precipitation sampling was performed at Zeppelin Station, Svalbard, from November 2009 until May 2011. The samples were analysed for NO3-; nss-SO42- and NH4+ concentrations, and the deposition of single precipitation events was calculated using precipitation measurements taken at nearby Ny-Alesund. The majority of observed events showed concentrations ranging from 0.01 to 0.1 mg L-1 N for NO3- and NH4+ and from 0.02 to 0.3 mg L-1 S for nss-SO42-. The majority of calculated depositions ranged from 0.01 to 0.1 mg m(-2) N for NO3- and NH4+ and from 0.02 to 0.3 mg m(-2) S for nss-SO42-. The budget was controlled by strong deposition events, caused by long-lasting precipitation episodes that lasted for several days and which had raised concentrations of nitrogen and sulphur. Three future scenarios of increasing precipitation in the Arctic were considered. The results showed that deposition is mainly controlled by the amount of precipitation, which leads to the conclusion that increased precipitation might cause increases in deposition of the same magnitude.

  • 9.
    Kylin, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Linköping University, Sweden; Norwegian Institute for Air Research, Fram Centre, Norway.
    Hammar, Johan
    Mowrer, Jacques
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bouwman, Henk
    Edelstam, Carl
    Olsson, Mats
    Jensen, Sören
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Persistent organic pollutants in biota samples collected during the Ymer-80 expedition to the Arctic2015In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 34, article id 21129Article in journal (Refereed)
    Abstract [en]

    During the 1980 expedition to the Arctic with the icebreaker Ymer, a number of vertebrate species were sampled for determination of persistent organic pollutants. Samples of Arctic char (Salvelinus alpinus, n = 34), glaucous gull (Larus hyperboreus, n = 8), common eider (Somateria mollissima, n = 10), Brunnich's guillemot (Uria lomvia, n = 9), ringed seal (Pusa hispida, n = 2) and polar bear (Ursus maritimus, n = 2) were collected. With the exception of Brunnich's guillemot, there was a marked contamination difference of birds from western as compared to eastern/northern Svalbard. Samples in the west contained a larger number of polychlorinated biphenyl (PCB) congeners and also polychlorinated terphenyls, indicating local sources. Brunnich's guillemots had similar pollutant concentrations in the west and east/north; possibly younger birds were sampled in the west. In Arctic char, pollutant profiles from lake Linnevatn (n = 5), the lake closest to the main economic activities in Svalbard, were similar to profiles in Arctic char from the Shetland Islands (n = 5), but differed from lakes to the north and east in Svalbard (n = 30). Arctic char samples had higher concentrations of hexachlorocyclohexanes (HCHs) than the marine species of birds and mammals, possibly due to accumulation via snowmelt. Compared to the Baltic Sea, comparable species collected in Svalbard had lower concentrations of PCB and dichlorodiphenyltrichloroethane (DDT), but similar concentrations indicating long-range transport of hexachlorobenzene, HCHs and cyclodiene pesticides. In samples collected in Svalbard in 1971, the concentrations of PCB and DDT in Brunnich's guillemot (n = 7), glaucous gull (n = 2) and polar bear (n = 2) were similar to the concentrations found in 1980.

  • 10.
    Löwemark, Ludvig
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Mörth, Magnus
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Backman, Jan
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Arctic Ocean manganese contents and sediment colour cycles2008In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 27, no 2, p. 105-113Article in journal (Refereed)
    Abstract [en]

    Cyclical variations in colour and Mn content in sediments from the central Arctic Ocean have been interpreted to represent climatically controlled changes in the input of Mn from the Siberian hinterland and/or variations in the intermediate and deep water ventilation of the Arctic basins, although a diagenetic origin has not been excluded. A reinvestigation of core 96/12-1pc using an Itrax XRF core scanner confirms that these colour cycles are indeed controlled by variations in Mn content, although changes in the source region of the sediment may override the Mn-colour signal in certain intervals. The prominent Mn cycles show no correspondence to any of the other measured elements. This decoupling of the Mn and the bulk chemistry of the sediment is taken to indicate that the cycles observed are caused by variations in water column ventilation and riverine input rather than variations in sediment source or diagenesis. We therefore conclude that the Mn cycles do represent warm phases with increased ventilation and/or riverine input, and that they therefore could be used for chronostratigraphic correlation between cores from the central Arctic Ocean where traditional isotope stratigraphy is difficult or impossible to establish due to the lack of calcareous microfossils.

  • 11.
    Norén, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Dalén, Love
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Flagstad, Øystein
    Berteaux, Dominique
    Wallén, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Evolution, ecology and conservation—revisiting three decades of Arctic fox population genetic research2017In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 36, no suppl. 1, article id 4Article in journal (Refereed)
    Abstract [en]

    Three decades have passed since the Arctic fox (Vulpes lagopus) was first put into a population genetic perspective. With the aim of addressing how microevolution operates on different biological levels, we here review genetic processes in the Arctic fox at the level of species, populations and individuals. Historical and present dispersal patterns, especially in the presence of sea ice, are the most powerful factors that create a highly homogeneous genetic structure across the circumpolar distribution, with low detectable divergence between the coastal and lemming ecotypes. With dispersal less pronounced or absent, other processes emerge; populations that are currently isolated, for example, because of the lack of sea ice, are genetically divergent. Moreover, small populations generally display signatures of genetic drift, inbreeding, inbreeding depression and, under specific situations, hybridization with domestic fox breeds. Mating system and social organization in the Arctic fox appear to be determined by the ecological context, with complex mating patterns and social groups being more common under resource-rich conditions. In isolated populations, complex social groups and inbreeding avoidance have been documented. We emphasize the value of genetic data to decipher many previously unknown aspects of Arctic fox biology, while these data also raise numerous questions that remain unanswered. Pronounced intra-specific ecological variation makes the Arctic fox an ideal study organism for population genetic processes and the emergence of functional genomics will generate an even deeper understanding of evolution, ecology and conservation issues for several species.

  • 12.
    O'Regan, Matthew
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Sellén, Emma
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Middle to late Quaternary grain size variations and sea-ice rafting on the Lomonosov Ridge2014In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 33, p. 23672-Article in journal (Refereed)
    Abstract [en]

    Sea ice and icebergs are the dominant transport agents for sand-sized material to the central Arctic Ocean. However, few studies have investigated concurrent changes in the silt-sized fraction of Arctic sediments. Here we present an analysis of the coarse fraction content and silt grain size composition from middle and late Quaternary sediments recovered from the Lomonosov Ridge, in the central Arctic Ocean. A significant shift in the grain size record occurs at the marine isotope stage (MIS) 6/7 boundary, where larger amplitude variability in the sand fraction is seen in glacial and stadial periods. Below the MIS6/7 boundary, variations in the coarse fraction content are less pronounced, but prominent changes in the silt size fraction appear to define glacial and interglacial periods. Throughout the record, the percent weight of sortable silt in the fine fraction (SS % wt(fines)), sortable silt mean size, and coarse silt content all increase as the >63 mu m % wt content increases. This is consistent with observations of grain size spectra obtained from modern sea-ice samples, and indicates a strong overprint from sea ice on the silt distribution. The mechanism by which this sea-ice signal is preserved in the sediments across glacial and interglacial periods remains unclear. We suggest that the coarsening of silt-sized material during glacial periods could be attributed to either the entrainment of larger size fractions during suspension/anchor ice formation when sea levels are lowered, or diminished input and advection of fine fraction material during glacial periods.

  • 13.
    Pannetier, Romain
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Frampton, Andrew
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Air warming trends linked to permafrost warming in the sub-Arctic catchment of Tarfala, Sweden2016In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 35, article id 28978Article in journal (Refereed)
    Abstract [en]

    Recent ground temperature records from the 100-m-deep borehole near the Tarfala Research Station in northern Sweden reveal that permafrost is warming at a pace consistent with the rate of measured air temperature increase at the site. Here we investigate whether air temperature increase is the main driver of the observed change in the permafrost thermal regime using a non-isothermal hydrogeological numerical model for partially frozen ground. The local site is investigated with different ground surface temperature scenarios representing different integrated effects of surficial heat attenuation processes. Results indicate that despite a short-term sensitivity to heat attenuation processes including snow conditions, the main driver of change in the permafrost thermal regime during the past decade is warming air temperatures. Additionally, the approach used here is shown to be particularly pertinent for modelling warming trends, despite limited prior knowledge of site-specific conditions and geological properties. Understanding the main driving mechanisms of changing permafrost is useful for assessing the suitability of borehole temperature records as proxies for past environmental conditions as well as for modelling possible future climatic impacts.

  • 14.
    Schneider, Andrea
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. University of Tromsø, Norway.
    Wetterich, Sebastian
    Schirrmeister, Lutz
    Herzschuh, Ulrike
    Meyer, Hanno
    Pestryakova, Lyudmila A.
    Freshwater ostracods (Crustacea) and environmental variability of polygon ponds in the tundra of the Indigirka Lowland, north-east Siberia2016In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 35, article id 25225Article in journal (Refereed)
    Abstract [en]

    Freshwater ostracods (Crustacea, Ostracoda) are valuable biological indicators. In Arctic environments, their habitat conditions are barely known and the abundance and diversity of ostracods is documented only in scattered records with incomplete ecological characterization. To determine the taxonomic range of ostracod assemblages and their habitat conditions in polygon ponds in the Indigirka Lowland, north-east Siberia, we collected more than 100 living ostracod individuals per site with a plankton net (mesh size 65 mm) and an exhaustor system from 27 water bodies and studied them in the context of substrate and hydrochemical data. During the summer of 2011, a single pond site and its ostracod population was selected for special study. This first record of the ostracod fauna in the Indigirka Lowland comprises eight species and three additional taxa. Fabaeformiscandona krochini and F. groenlandica were documented for the first time in continental Siberia. Repeated sampling of a low-centre polygon pond yielded insights into the population dynamics of F. pedata. We identified air temperature and precipitation as the main external drivers of water temperatures, water levels, ion concentrations and water stable isotope composition on diurnal and seasonal scales.

  • 15.
    Thompson, Bijoy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Nilsson, Johan
    Stockholm University, Faculty of Science, Department of Meteorology .
    Nycander, Jonas
    Stockholm University, Faculty of Science, Department of Meteorology .
    Doos, Kristofer
    Stockholm University, Faculty of Science, Department of Meteorology .
    A model study of the first ventilated regime of the Arctic Ocean during the early Miocene2012In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 31, p. 10859-Article in journal (Refereed)
    Abstract [en]

    The tectonic opening of Fram Strait during the Neogene was a significant geological event that transferred the Arctic Ocean from a poorly ventilated enclosed basin, with weak exchange with the North Atlantic, to a fully ventilated ocean stage''. Previous tectonic and physical oceanographic analyses suggest that the early Miocene Fram Strait was likely several times narrower and less than half as deep as the present-day 400 km wide and 2550 m deep strait. Here we use an ocean general circulation model with a passive age tracer included to further address the effect of the Fram Strait opening on the early Miocene Arctic Ocean circulation. The model tracer age exhibits strong spatial gradient between the two major Arctic Ocean deep basins: the Eurasian and Amerasian basins. There is a two-layer stratification and the exchange flow through Fram Strait shows a bi-layer structure with a low salinity outflow from the Arctic confined to a relatively thin upper layer and a saline inflow from the North Atlantic below. Our study suggests that although Fram Strait was significantly narrower and shallower during early Miocene, and the ventilation mechanism quite different in our model, the estimated ventilation rates are comparable to the chemical tracer estimates in the present-day Arctic Ocean. Since we achieved ventilation of the Arctic Ocean with a prescribed Fram Strait width of 100 km and sill depth of 1000 m, ventilation may have preceded the timing of a full ocean depth connection between the Arctic Ocean and North Atlantic established through seafloor spreading and the development of the Lena Trough.

  • 16. Wegner, Carolyn
    et al.
    Bennett, Katrina E.
    de Vernal, Anne
    Forwick, Matthias
    Fritz, Michael
    Heikkila, Maija
    Lacka, Magdalena
    Lantuit, Hugues
    Laska, Michal
    Moskalik, Mateusz
    O'Regan, Matt
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Pawlowska, Joanna
    Prominska, Agnieszka
    Rachold, Volker
    Vonk, Jorien E.
    Werner, Kirstin
    Variability in transport of terrigenous material on the shelves and the deep Arctic Ocean during the Holocene2015In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 34, article id 24964Article in journal (Refereed)
    Abstract [en]

    Arctic coastal zones serve as a sensitive filter for terrigenous matter input onto the shelves via river discharge and coastal erosion. This material is further distributed across the Arctic by ocean currents and sea ice. The coastal regions are particularly vulnerable to changes related to recent climate change. We compiled a pan-Arctic review that looks into the changing Holocene sources, transport processes and sinks of terrigenous sediment in the Arctic Ocean. Existing palaeoceanographic studies demonstrate how climate warming and the disappearance of ice sheets during the early Holocene initiated eustatic sea-level rise that greatly modified the physiography of the Arctic Ocean. Sedimentation rates over the shelves and slopes were much greater during periods of rapid sea-level rise in the early and middle Holocene, as a result of the relative distance to the terrestrial sediment sources. However, estimates of suspended sediment delivery through major Arctic rivers do not indicate enhanced delivery during this time, which suggests enhanced rates of coastal erosion. The increased supply of terrigenous material to the outer shelves and deep Arctic Ocean in the early and middle Holocene might serve as analogous to forecast changes in the future Arctic.

  • 17.
    Weiss, Niels
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Faucherre, Samuel
    Lampiris, Nikos
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Wojcik, Robin
    Stockholm University, Faculty of Science, Department of Physical Geography. German Research Centre for Geoscience, Germany.
    Elevation-based upscaling of organic carbon stocks in High-Arctic permafrost terrain: a storage and distribution assessment for Spitsbergen, Svalbard2017In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 36, article id 1400363Article in journal (Refereed)
    Abstract [en]

    Accurate quantity and distribution estimates of permafrost soil organic carbon (SOC) stocks are needed to project potential feedbacks to climate, following warming. Still, upscaling from local field observations to regional estimates to circumarctic assessments remains a challenge. Here we explore elevation-based upscaling techniques for High-Arctic permafrost SOC stocks. We combine two detailed, high-resolution SOC inventories on Spitsbergen (Svalbard) with regional validation data. We find a clear relationship between elevation and SOC content, and use this observed exponential correlation, as well as discrete elevation classes, as upscaling models for Spitsbergen. We estimate the total amount of permafrost SOC currently present in soils on Spitsbergen to be 105.36 Tg (0.11 Pg), with a mean SOC content of 2.84 +/- 0.74 kg C m(-2) (mean +/- 95% confidence interval). Excluding glaciers and permanent snowfields, exposed land is currently estimated to contain 6.26 +/- 1.47 kg C m(-2).

1 - 17 of 17
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf