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  • 1
    Digitale Medien
    Digitale Medien
    The marine ecosystem of Kongsfjorden, Svalbard (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 21 (2002), S. 0 
    Details
    ISSN: 1751-8369
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geographie , Geologie und Paläontologie
    Notizen: Kongsfjorden is a glacial fjord in the Arctic (Svalbard) that is influenced by both Atlantic and Arctic water masses and harbours a mixture of boreal and Arctic flora and fauna. Inputs from large tidal glaciers create steep environmental gradients in sedimentation and salinity along the length of this fjord. The glacial inputs cause reduced biomass and diversity in the benthic community in the inner fjord. Zooplankton suffers direct mortality from the glacial outflow and primary production is reduced because of limited light levels in the turbid, mixed inner waters. The magnitude of the glacial effects diminishes towards the outer fjord. Kongsfjorden is an important feeding ground for marine mammals and seabirds. Even though the fjord contains some boreal fauna, the prey consumed by upper trophic levels is mainly Arctic organisms. Marine mammals constitute the largest top-predator biomass, but seabirds have the largest energy intake and also export nutrients and energy out of the marine environment. Kongsfjorden has received a lot of research attention in the recent past. The current interest in the fjord is primarily based on the fact that Kongsfjorden is particularly suitable as a site for exploring the impacts of possible climate changes, with Atlantic water influx and melting of tidal glaciers both being linked to climate variability. The pelagic ecosystem is likely to be most sensitive to the Atlantic versus Arctic influence, whereas the benthic ecosystem is more affected by long-term changes in hydrography as well as changes in glacial runoff and sedimentation. Kongsfjorden will be an important Arctic monitoring site over the coming decades and a review of the current knowledge, and a gap analysis, are therefore warranted. Important knowledge gaps include a lack of quantitative data on production, abundance of key prey species, and the role of advection on the biological communities in the fjord.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1751-8369.2002.tb00073.x
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  • 2
    Digitale Medien
    Digitale Medien
    Polar bivalves are characterized by high antioxidant defences (2005)
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 24 (2005), S. 0 
    Details
    ISSN: 1751-8369
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geographie , Geologie und Paläontologie
    Notizen: Inevitably, aerobic life leads to the formation of deleterious reactive oxygen species (ROS) which participate in biomolecule oxidation, hence augmenting biomolecule turnover. Organisms have adapted to counteract the noxious effects of ROS by developing a battery of antioxidant defences (AOX) which comprise enzymes and low-molecular weight scavengers. Past studies have reported elevated AOX levels in polar pectinid bivalves compared with temperate congeners. This finding is controversial as mitochondrial ROS generation is low in polar versus temperate species, and, to date, there is no generally accepted explanation of the causes of increased basal AOX levels in polar waters. We suggest that the low food availability in those ecosystems may result in polar marine ectotherms diverting some energy into the maintenance of high AOX. We tested this hypothesis by comparing the total oxyradical scavenging capacity (peroxyl, hydroxyl and peroxynitrite) of three clam species: Laternula elliptica (Antarctic), Mya truncata (Arctic) and Mya arenaria (temperate). The data confirmed that polar bivalves are characterized by higher AOX. Herein, we propose that high AOX is required in environments characterized by low food availability as AOX efficiently protects biomolecules, notably the RNA expressed at high levels by cold-water ectotherms. Also, high AOX may explain the relatively long lifespan of most polar ectotherms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1751-8369.2005.tb00144.x
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  • 3
    Digitale Medien
    Digitale Medien
    Fatty acid composition of the blubber in white whales (Delphinapterus leucas) (2000)
    Springer
    Polar biology 23 (2000), S. 401-409 
    Details
    ISSN: 1432-2056
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Fatty acid (FA) composition of the blubber in free-ranging white whales (Delphinapterus leucas) from Svalbard's waters was determined and compared with the fatty acid composition of potential prey species in an attempt to assess diet. This methodology is based on the common assumption that unique arrays of FAs found within groups of organisms are transferred, largely unaltered, up marine food chains and thus may be useful for assessment of diet composition. Complete-column blubber biopsies were sampled from white whales (n=7) during the summers of 1996 and 1997. All captured animals were adult males. FAs were extracted from 2–4 replicates taken from an area about 10 cm in front of the mid-dorsal ridge. FA data from a total of 12 potential prey species from the Svalbard area were compared to the white-whale blubber samples. Twenty-two FAs were consistently found in relative amounts 〉0.5% of the total FA composition in white whales. These FAs accounted for 94–96% of the total FAs present. The blubber was composed almost entirely of triacylglycerols. The major saturated FAs were 14:0 and 16:0; 16:1(n-7), 18:1(n-9) and 20:1(n-9) were the major monounsaturated FAs and 20:5(n-3) and 22:6(n-3) were the major polyunsaturated FAs. Sixteen of the 22 FAs consistently found in the white-whale blubber were also found in considerable amounts (〉0.5% of total FAs) in most of the potential species. Principal Component Analysis run on these 16 FAs suggests that polar cod (Boreogadus saida) had the most similar FA composition to the white-whale blubber, followed by capelin (Mallotus villosus), the copepod Calanus hyperboreus and the shrimp Pandalus borealis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003000050461
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  • 4
    Digitale Medien
    Digitale Medien
    Ecology of sea ice biota (1992)
    Springer
    Polar biology 12 (1992), S. 417-427 
    Details
    ISSN: 1432-2056
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Polar regions are covered by extensive sea ice that is inhabited by a variety of plants and animals. The environments where the organisms live vary depending on the structure and age of the ice. Many terms have been used to describe the habitats and the organisms. We here characterize the habitats and communities and suggest some standard terms for them. We also suggest routine sampling methods and reporting units for measurements of biological and chemical variables.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00243113
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  • 5
    Digitale Medien
    Digitale Medien
    Ecology of sea ice biota (1992)
    Springer
    Polar biology 12 (1992), S. 429-444 
    Details
    ISSN: 1432-2056
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The sea ice does not only determine the ecology of ice biota, but it also influences the pelagic systems under the ice cover and at ice edges. In this paper, new estimates of Arctic and Antarctic production of biogenic carbon are derived, and differences as well as similarities between the two oceans are examined. In ice-covered seas, high algal concentrations (blooms) occur in association with several types of conditions. Blooms often lead to high sedimentation of intact cells and faecal pellets. In addition to ice-related blooms, there is progressive accumulation of organic matter in Arctic multi-year ice, whose fate may potentially be similar to that of blooms. A fraction of the carbon fixed by microalgae that grow in sea ice or in relation to it is exported out of the production zone. This includes particulate material sinking out of the euphotic zone, and also material passed on to the food web. Pathways through which ice algal production does reach various components of the pelagic and benthic food webs, and through them such top predators as marine mammals and birds, are discussed. Concerning global climate change and biogeochemical fluxes of carbon, not all export pathways from the euphotic zone result in the sequestration of carbon for periods of hundreds of years or more. This is because various processes, that take place in both the ice and the water column, contribute to mineralize organic carbon into CO2 before it becomes sequestered. Processes that favour the production and accumulation of biogenic carbon as well as its export to deep waters and sequestration are discussed, together with those that influence mineralization in the upper ice-covered ocean.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00243114
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  • 6
    Digitale Medien
    Digitale Medien
    Environmental influences on benthic fauna associations of the Kara Sea (Arctic Russia) (1999)
    Springer
    Polar biology 22 (1999), S. 395-416 
    Details
    ISSN: 1432-2056
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Macrobenthic faunal associations, hydrography and sediment structure were examined at 14 stations in the Kara Sea. The stations were located in an area influenced by huge runoff from the Ob and Yenisei Rivers and in areas influenced by Barents Sea water. Sampling depths varied from 17 to 43 m, with one station at 195 m. The sediments were predominantly muddy but some stations were sandy. Three hundred and eighty-seven taxa were identified and Polychaeta, Crustacea and Mollusca were the most conspicuous. Species number, abundance and biomass varied widely among stations, and were generally higher in the more marine waters. Boreal-arctic species predominated, but an increase of arctic species from marine to the estuarine areas was evident. Five faunal associations were delineated by cluster analysis and suggested quite heterogeneous sampling areas. The most conspicuous species of each faunal association were Spiochaetopterus typicus, Tridonta borealis, Serripes groenlandicus, Portlandia arctica, and Marenzelleria arctia, respectively. The sedimentation rate, as well as depth, sediment structure and salinity, apparently influenced the main differences in the fauna.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003000050435
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  • 7
    Digitale Medien
    Digitale Medien
    Structure, biomass distribution, and energetics of the pelagic ecosystem in the Barents Sea: A synopsis (1994)
    Springer
    Polar biology 14 (1994), S. 405-411 
    Details
    ISSN: 1432-2056
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Biomass distribution and energetics of trophic levels in the pelagic ecosystem of the Barents Sea are presented as averages over several years for the whole Barents Sea using data from the research programme Pro Mare in 1984–1989 and mathematical ecosystem models. Average biomasses range from more than 3 tonnes carbon km−2 (zooplankton) to 0.1 kg C km−2 (polar bears) and P/B ratios from 300 (bacteria) to 0.035 (minke whales). However, the Barents Sea ecosystem is in a far from steady state with, for instance, capelin stocks ranging from 30–700 kg C km−2 between years and cod stocks from 150–700 kg C km−2. As a general rule, the various fish stocks grow adequately, albeit at different rates, in “warm” years characterized by large influxes of Atlantic water and high zooplankton productivity. The skewed populations distribution which arises in “warm” years may lead to grave imbalances in “cold” years and even to the “collapses” of stocks, such as of capelin in the eighties. The food requirements of average-sized stocks of cod, seabirds and marine mammals correspond to more than twice the average productivity of capelin. Thus other species of pelagic fish (herring, polar cod) and zooplankton obviously play major roles as prey for these animals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00240261
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  • 8
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    Unbekannt
    (Table 1) Zooplankton counts and volumes from Tucker trawl samples at Rijpfjorden
    PANGAEA
    Details
    Publikationsdatum: 2023-05-12
    Schlagwort(e): DEPTH, water; Limacina helicina; MULT; Multiple investigations; Nordaustlandet fjords, Svalbard; Rijpfjorden; Themisto libellula; Time of day; Volume
    Materialart: Dataset
    Format: text/tab-separated-values, 40 data points
    Standort Signatur Einschränkungen Verfügbarkeit
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    DATA PANGAEA
  • 9
    facet.materialart.
    Unbekannt
    (Table 3) Stomach contents of Boreogadus saida specimens obtained during trawling at Rijpfjorden
    PANGAEA
    Details
    Publikationsdatum: 2023-05-12
    Schlagwort(e): Boreogadus saida; Boreogadus saida, length; Boreogadus saida, stomach content; DEPTH, water; Length, standard deviation; MULT; Multiple investigations; Nordaustlandet fjords, Svalbard; Rijpfjorden; Time of day
    Materialart: Dataset
    Format: text/tab-separated-values, 44 data points
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    DATA PANGAEA
  • 10
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    Unbekannt
    (Table 5) Abundance of mesozooplankton in the upper 1200 m at ice stations 1 and 2, Arctic Ocean (2008)
    PANGAEA
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    Publikationsdatum: 2023-07-10
    Schlagwort(e): Appendicularia; Arctic Ocean; Calanus finmarchicus; Calanus glacialis; Calanus hyperboreus; Calanus spp.; Chaetognatha; Depth, bottom/max; Depth, top/min; DEPTH, water; Event label; Ice-St_04-1; Ice-St_04-2; Metridia longa; MULT; Multiple investigations; Station label; Time of day
    Materialart: Dataset
    Format: text/tab-separated-values, 210 data points
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    DATA PANGAEA
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