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1.
Abundance, biomass and small-scale distribution of cryopelagic amphipods in the Franz Josef Land area (Arctic) 总被引:3,自引:3,他引:0
M. Poltermann 《Polar Biology》1998,20(2):134-138
Arctic sea ice is inhabited by several amphipod species. Abundance, biomass and small-scale distribution of these cryopelagic
(=ice associated) amphipods were investigated near Franz Josef Land in summer 1994. The mean abundance of all species was
420 ind./m2; the mean biomass was 10.61 g ww/m2. Gammarus wilkitzkii was the dominant species, whereas Apherusa glacialis, Onisimus nanseni and O. glacialis were only scarcely found. Amphipods were concentrated at the edges of ice floes and were less frequent in areas further away
under the ice. The relationship between the distribution and ecological/physiological requirements of cryopelagic amphipods,
as well as the small-scale morphology of Arctic sea ice, are discussed.
Received: 14 January 1998 / Accepted 14 April 1998 相似文献
2.
Zooplankton composition and distribution were investigated on the Laptev Sea shelf, over the continental slope and in the
adjacent deep Nansen Basin during the joint German-Russian expedition “Arctic 93” with RV Polarstern and Ivan Kireyev in August/September 1993. In the shelf area biomass decreased from west to east with the lowest values in the area influenced
by the Lena river runoff. A gradual increase of biomass from the shallow to the deep area correlated with water depth. Total
biomass ranged between 0.1 and 1.5 g m−2 on the shelf and 4.7 and 7.9 g m−2 in the adjacent Nansen Basin. On the shelf Calanus glacialis/finmarchicus dominated overall. The contribution of brackish-water taxa was low in the west, where high salinity and southward currents
from the Arctic Basin supported a marine neritic community, but on the southern and eastern Laptev shelf, in the areas of
freshwater influence, brackish-water taxa contributed up to 27% of the total biomass. On the slope and in deep areas a few
large Arctic copepod species, Calanus glacialis, C. hyperboreus and Metridia longa, composed the bulk of biomass and determined the pattern of its vertical distribution. The export of Calanus species from the Nansen Basin onto the Laptev shelf appears to be of great importance for the shelf communities. In turn,
the eastern outer shelf and slope area of the Laptev Sea are thought to have a pronounced effect on the deep basin, modifying
the populations entering the central Arctic.
Received: 25 March 1997 / Accepted: 18 July 1997 相似文献
3.
M. Poltermann 《Polar Biology》2001,24(2):89-96
The amphipod species Gammarus wilkitzkii, Apherusa glacialis, Onisimus nanseni and O. glacialis live permanently associated with the Arctic sea ice. Qualitative and semi-quantitative investigations of gut contents and
faeces showed that all four species use detritus as the main food source. Detrital lumps from the underside of sea ice had
the same item composition as amphipod gut contents and faeces. Crustacean remains and ice algae were additional food items,
but overall they were quantitatively less important. All species are omnivorous; however, differences in gut contents, behavioural
observations and functional–morphological studies of the mandibles suggest a differentiation within this feeding strategy.
G. wilkitzkii is a detritivorous-carnivorous-necrophagous-suspension-feeding species and shows the most complex feeding strategy. O. nanseni and O. glacialis are predominantly detritivorous-necrophagous, whereas A. glacialis is characterised as a more herbivorous-detritivorous species. By using a variety of the available food sources under Arctic
sea ice, the amphipods are well adapted to the under-ice habitat and are less influenced by temporal and spatial variations.
Furthermore, the wide food spectrum of all four species reduces the intra- and interspecific competition in a habitat where
certain food sources are limited or only seasonally available.
Accepted: 30 June 2000 相似文献
4.
Currently, the impact of declining seasonal sea ice extent in the Arctic on polar food webs remains uncertain. Previously,
a range of proxy techniques has been employed to determine links between sea ice or phytoplankton primary production and the
Arctic marine food web, although it is accepted that such approaches have their limitations. Here, we propose a novel approach
to tracing sea ice primary production through Arctic food webs using the sea ice diatom biomarker, IP25. Various benthic macrofaunal specimens were collected between March and May 2008 from Franklin Bay in the Amundsen Gulf,
Arctic Canada, as part of the International Polar Year–Circumpolar Flaw Lead system study. Each specimen was analysed for
the presence of the sea ice diatom biomarker IP25 in order to provide evidence for feeding by benthic organisms on sea ice algae. IP25 was found in nineteen out of the twenty-one specimens analysed, often as the most abundant of the highly branched isoprenoid
biomarkers detected. The stable isotope composition of IP25 (δ13C = −17.1 ± 0.5‰) in the sea urchin (Strongylocentrotus sp.) specimens was similar to that reported previously for this biomarker in Arctic sea ice, sedimenting particles and sediments.
It is concluded that detection of IP25 in Arctic benthic macrofauna represents a novel approach to providing convincing evidence for feeding on sea ice algae. It
is also proposed that analysis of IP25 may be used to trace trophic transfer of sea ice algal-derived organic matter through Arctic food webs in the future. 相似文献
5.
Lemmings are involved in several important functions in the Arctic ecosystem. The Arctic fox (Vulpes lagopus) can be divided into two discrete ecotypes: “lemming foxes” and “coastal foxes”. Crashes in lemming abundance can result
in pulses of “lemming fox” movement across the Arctic sea ice and immigration into coastal habitats in search for food. These
pulses can influence the genetic structure of the receiving population. We have tested the impact of immigration on the genetic
structure of the “coastal fox” population in Svalbard by recording microsatellite variation in seven loci for 162 Arctic foxes
sampled during the summer and winter over a 5-year period. Genetic heterogeneity and temporal genetic shifts, as inferred
by STRUCTURE simulations and deviations from Hardy–Weinberg proportions, respectively, were recorded. Maximum likelihood estimates
of movement as well as STRUCTURE simulations suggested that both immigration and genetic mixture are higher in Svalbard than
in the neighbouring “lemming fox” populations. The STRUCTURE simulations and AMOVA revealed there are differences in genetic
composition of the population between summer and winter seasons, indicating that immigrants are not present in the reproductive
portion of the Svalbard population. Based on these results, we conclude that Arctic fox population structure varies with time
and is influenced by immigration from neighbouring populations. The lemming cycle is likely an important factor shaping Arctic
fox movement across sea ice and the subsequent population genetic structure, but is also likely to influence local adaptation
to the coastal habitat and the prevalence of diseases. 相似文献
6.
Microscale photographs were taken of the ice bottom to examine linkages of algal chlorophyll a (chl a) biomass distribution with bottom ice features in thick Arctic first-year sea ice during a spring field program which took
place from May 5 to 21, 2003. The photographic technique developed in this paper has resulted in the first in situ observations
of microscale variability in bottom ice algae distribution in Arctic first-year sea ice in relation to ice morphology. Observations
of brine channel diameter (1.65–2.68 mm) and number density (5.33–10.35 per 100 cm2) showed that the number of these channels at the bottom of thick first-year sea ice may be greater than previously measured
on extracted ice samples. A variogram analysis showed that over areas of low chl a biomass (≤20.7 mg chl a m−2), patchiness in bottom ice chl a biomass was at the scale of brine layer spacing and small brine channels (∼1–3 mm). Over areas of high chl a biomass (≥34.6 mg chl a m−2), patchiness in biomass was related to the spacing of larger brine channels on the ice bottom (∼10–26 mm). Brine layers and
channels are thought to provide microscale maxima of light, nutrient replenishment and space availability which would explain
the small scale patchiness over areas of low algal biomass. However, ice melt and erosion near brine channels may play a more
important role in areas with high algal biomass and low snow cover. 相似文献
7.
Little research has been conducted on effects of iteroparous anadromous fishes on Arctic lakes. We investigated trophic ecology,
fish growth, and food web structure in six lakes located in Nunavut, Canada; three lakes contained anadromous Arctic charr
(Salvelinus alpinus) whereas three lakes did not contain Arctic charr. All lakes contained forage fishes and lake trout (Salvelinus namaycush; top predator). Isotope ratios (δ13C, δ15N) of fishes and invertebrates did not differ between lakes with and without anadromous Arctic charr; if anadromous Arctic
charr deliver marine-derived nutrients and/or organic matter to freshwater lakes, these inputs could not be detected with
δ13C and/or δ15N. Lake trout carbon (C):nitrogen (N) and condition were significantly higher in lakes with Arctic charr (C:N = 3.42, K = 1.1) than in lakes without Arctic charr (C:N = 3.17, K = 0.99), however, and ninespine stickleback (Pungitius pungitius) condition was significantly lower in lakes with Arctic charr (K = 0.58) than in lakes without Arctic charr (K = 0.64). Isotope data indicated that pre-smolt and resident Arctic charr may be prey for lake trout and compete with ninespine
stickleback. Linear distance metrics applied to isotope data showed that food webs were more compact and isotopically redundant
in lakes where Arctic charr were present. Despite this, lake trout populations in lakes with Arctic charr occupied a larger
isotope space and showed greater inter-individual isotope differences. Anadromous Arctic charr appear to affect ecology and
feeding of sympatric freshwater species, but effects are more subtle than those seen for semelparous anadromous species. 相似文献
8.
F. Riget E. Jeppesen F. Landkildehus T. L. Lauridsen P. Geertz-Hansen K. Christoffersen H. Sparholt 《Polar Biology》2000,23(8):550-558
Landlocked Arctic charr (Salvelinus alpinus) populations in sub-Arctic and Arctic Greenland lakes were sampled with multi-mesh-sized survey gillnets. The study covered
a range of small shallow lakes (0.01 km2, maximum depth <3.3 m) to large deep lakes (43 km2, maximum depth >200 m). Arctic charr were found in one to three different forms in lakes with maximum depths >3 m. A dwarf
form occurred in all lakes inhabited by Arctic charr and was the only form in lakes with maximum depths <8 m. In deeper lakes
with maximum depths >20 m and a surface area <0.5 km2, larger charr were found, although in low numbers, the length-frequency distribution being unimodal with a tail towards large
sizes. In lakes with a maximum depth >20 m, large-sized charr were more abundant, and the length-frequency distribution of
the population was bimodal, with a first mode around 10–12 cm and a second mode around 26–37 cm. In a single large and deep
lake, a distinct medium-sized pelagic zooplankton-eating charr form occurred. Maximum size of individual charr was significantly
positively correlated with lake maximum depth and volume, and the mean size of large-sized charr was significantly positively
correlated with lake volume. Our study indicates that the charr population structure became more complex with increasing lake
size. Moreover, the population structure seemed to be influenced by lake-water transparency and the presence or absence of
three-spined stickleback (Gasterosteus aculeatus).
Accepted: 31 January 2000 相似文献
9.
Integrated abundance and biomass of sympagic meiofauna in Arctic and Antarctic pack ice 总被引:3,自引:0,他引:3
R. Gradinger 《Polar Biology》1999,22(3):169-177
The abundance and biomass of sympagic meiofauna were studied during three cruises to the Antarctic and one summer expedition
to the central Arctic Ocean. Ice samples were collected by ice coring and algal pigment concentrations and meiofauna abundances
were determined for entire cores. Median meiofauna abundances for the expeditions ranged from 4.4 to 139.5 × 103 organisms m−2 in Antarctic sea ice and accounted for 40.6 × 103 organisms m−2 in Arctic multi-year sea ice. While most taxa (ciliates, foraminifers, turbellarians, crustaceans) were common in both Arctic
and Antarctic sea ice, nematodes and rotifers occurred only in the Arctic. Based on the calculated biomass, the potential
meiofauna ingestion rates were determined by applying an allometric model. For both hemispheres, daily and yearly potential
ingestion rates were below the production values of the ice algal communities, pointing towards non-limited feeding conditions
for ice meiofauna year-round.
Accepted: 29 March 1999 相似文献
10.
Colleen T. E. Kellogg Shelly D. Carpenter Alisha A. Renfro Am��lie Sallon Christine Michel J. Kirk Cochran Jody W. Deming 《Polar Biology》2011,34(12):2007-2023
Export of autochthonously produced particulate organic carbon (POC) is a globally important mechanism for sequestering carbon
in the deep sea. The role of microbial hydrolytic activity in attenuating POC flux is generally understudied, and particularly
complex on Arctic continental shelves influenced by other sources of POC. To evaluate this role, we used fluorogenic substrate
analogs to measure extracellular enzyme activity (EEA) associated with particle size fractions considered suspended (1–70 μm)
and sinking (>70 μm). Samples were collected by in situ filtration at depths of 25–100 m at ten stations (156–1,142 m deep)
in the Amundsen Gulf and Beaufort Sea in June–July, 2008, during the Circumpolar Flaw Lead project. Significant positive correlations
observed between EEA and both chlorophyll a and δ13CPOC suggest that EEA is elevated in waters dominated by marine-derived POC. No difference in bulk EEA was observed between size
fractions, but POC- and cell-specific EEA was significantly elevated on sinking aggregates. Calculations show that 2–44% of
carbon retention in surface waters could be attributed to mobilization by enzymes associated with sinking aggregates, and
up to 57% if enzymes associated with suspended particles are included. Model results suggest that microbial attenuation of
POC below the euphotic zone is a quantitatively important mechanism for carbon loss, especially when particles are sinking
slowly. The role of microbes in attenuating POC flux on Arctic shelves appears to have been underestimated previously and
may become increasingly important if climate warming brings increased marine productivity. 相似文献
11.
A collection of fossils sampled during the 1898–1902 expedition of theFram to the Canadian Arctic Islands includes abundant bryozoans from the Lower Permian (Artinskian) Great Bear Cape Formation
of Ellesmere Island. From this material a new genus with one new species —Nansenopora peculiaris n. gen., n. sp. — as well as three new species —Streblotrypella arctica n. sp.,Phragmophera patricki n. sp. andKallodictyon spinatum n. sp. — are described. Furthermore, the speciesUlrichotrypa ramulosa
Bassler, 1929 is reported for the first time from the Lower Permian of the Arctic region. 相似文献
12.
The conduction properties of peripheral nerves from the Arctic fish species Arctic eelpouts (Lycodes sp.), snake blenny (Lumpenus lampretaeformis) and polar cod (Boreogadus saida), permanently adapted to low temperatures, were studied. Nerves of these fishes have two types of fibres, characterised by
extracellular compound action potentials with fast (7 m/s) and slow (4 m/s) conduction velocities, as measured at 12 °C. The
temperature dependence of the conduction velocity was bimodal, changing its slope at about 16 °C. The Q
10 above 16 °C was 1.12–1.49, while below 16 °C it was 1.82–2.16. Irreversible deterioration of the nerve was observed at temperatures
around 19–27 °C. A comparison with data previously obtained from Mediterranean fishes indicates that Arctic fishes have similar
temperature sensitivity of nerve conduction and a slight vertical displacement on the conduction velocity-temperature curves,
which is insufficient to compensate the decrease of the conduction velocity at their physiological temperature, the conduction
velocity of Arctic fishes being about one-half of that of temperate fishes. This suggests that this neurophysiological function
is not fully cold-adapted in these Arctic fish species.
Accepted: 3 June 2000 相似文献
13.
Jürgen Weissenberger 《Polar Biology》1998,19(3):151-159
A mesocosm experiment (enclosure volume 220 l) was designed such that sea ice inhabited by Arctic Sea ice organisms was formed
and maintained under natural conditions at 66°N in Rovaniemi, Finland. The experiment was run from natural freezing in December
1994 to melting in April 1995. The ice was inhabited by diatoms, chlorophyceae, heterotrophic flagellates, ciliates, nematodes
and turbellarians. Biomass in the ice, expressed as Chlorophyll a concentration, was 20–110 μg l−1; total cell densities varied from 5 × 106 to 35 × 106 cells l−1. Amongst phototrophic organisms, a succession from a flagellate-dominated community (Chlamydomonas sp.) to a multi-species diatom-dominated community was observed. Typical Arctic species such as Nitzschia frigida and Melosira arctica were present in the ice. Bacterial concentration varied between 2 × 108 and 7 × 108 cells l−1. At least two trophic levels were present in the ice.
Received: 3 April 1997 / Accepted: 9 September 1997 相似文献
14.
George M. Durner John P. Whiteman Henry J. Harlow Steven C. Amstrup Eric V. Regehr Merav Ben-David 《Polar Biology》2011,34(7):975-984
Polar bears (Ursus maritimus) prefer to live on Arctic sea ice but may swim between ice floes or between sea ice and land. Although anecdotal observations
suggest that polar bears are capable of swimming long distances, no data have been available to describe in detail long distance
swimming events or the physiological and reproductive consequences of such behavior. Between an initial capture in late August
and a recapture in late October 2008, a radio-collared adult female polar bear in the Beaufort Sea made a continuous swim
of 687 km over 9 days and then intermittently swam and walked on the sea ice surface an additional 1,800 km. Measures of movement
rate, hourly activity, and subcutaneous and external temperature revealed distinct profiles of swimming and walking. Between
captures, this polar bear lost 22% of her body mass and her yearling cub. The extraordinary long distance swimming ability
of polar bears, which we confirm here, may help them cope with reduced Arctic sea ice. Our observation, however, indicates
that long distance swimming in Arctic waters, and travel over deep water pack ice, may result in high energetic costs and
compromise reproductive fitness. 相似文献
15.
Breaking the ice: large-scale distribution of mesozooplankton after a decade of Arctic and transpolar cruises 总被引:4,自引:4,他引:0
Mesozooplankton collected during five summer expeditions to the Arctic Ocean between 1987 and 1991 was analysed for regional
patterns in biomass and species distribution, distinguishing between an epipelagic (0–100 m) and a deeper (0–500 m) layer.
A total of 58 stations was sampled mainly in the Nansen, Amundsen and Makarov Basins of the central Arctic Ocean and in areas
of the Greenland Sea, West Spitsbergen Current and Barents Sea. Results from the different expeditions were combined to create
a transect extending from the Fram Strait across the Eurasian Basin into the Makarov Basin. Mesozooplankton dry mass in the
upper 500 m decreased from 8.4 g m−2 in the West Spitsbergen Current to less than 2 g m−2 in the high-Arctic deep-sea basins. In the central Arctic Ocean, biomass was concentrated in the upper 100 m and was dominated
by the large copepods Calanus hyperboreus and C. glacialis. In contrast, the mesozooplankton in the West Spitsbergen Current was more evenly distributed throughout the upper 500 m,
with C. finmarchicus as the prevailing species. The distribution of abundant mesopelagic species reflected the hydrographic regime: the calanoid
copepod Gaetanus tenuispinus and the hyperiid amphipod Themisto abyssorum were most abundant in the Atlantic inflow, while Scaphocalanus magnus was a typical component of the high-Arctic fauna. The relatively high mesozooplankton biomass and the occurrence of boreal-Atlantic
species in the central Arctic Ocean are indicators for the import of organic material from allochthonous sources, especially
from the northern North Atlantic. Hence, in spite of its enclosure by land masses, the Arctic Ocean is characterized by an
exchange of water masses and organisms with the North Atlantic, and advection processes strongly influence the distribution
of plankton species in this high-latitude ecosystem.
Received: 18 December 1997 / Accepted: 11 April 1998 相似文献
16.
The biomass and productivity of sea ice algae was assessed in the northwestern Barents Sea in May 2004. Sea ice algal pigment
content was patchy with a mean of 18.5 ± 8.9 mg Chla m−2. The algal community was dominated by the diatom Nitzschia frigida. Primary production measured by 14C incubations was between 0.37 and 2.8 mg C m−2 h−1, which compared well with oxygen-based methods using the diffusive boundary layer approach (0.071–1.1 mg C m−2 h−1). Given the differences in the irradiances under which these two sets of measurements were made, there was a strong level
of consistency between the two sets of results. Measurements of primary production were consistent with previous Arctic measurements
but high spatial heterogeneity made a regional estimate of production inappropriate. 相似文献
17.
Michaela Aschan Oleg V. Karamushko Ingvar Byrkjedal Rupert Wienerroither Igor V. Borkin Jørgen S. Christiansen 《Polar Biology》2009,32(7):963-970
The Arctogadus glacialis is endemic to the Arctic Ocean and its apparently disjunct circumpolar distribution range from the Siberian coast through
the Chukchi Sea and the Canadian Arctic to the shelf off NE Greenland. Records of A. glacialis are scarce in the European Arctic and here we present all available and reliable records of the species in the area. Altogether,
296 specimens of A. glacialis are reported from 53 positions in the European Arctic during the period 1976–2008. The specimens were registered off Iceland
and the Jan Mayen Island, northwest and northeast of Svalbard, northeast in the Barents Sea, and south and east off Franz
Josef Land. The additional records show that A. glacialis display a circumpolar and more continuous distribution than described before. In the European Arctic, A. glacialis has been caught at 155–741 m depth with the highest abundance at 300–400 m. We therefore suggest that A. glacialis is more associated to the continental shelves surrounding the Arctic Ocean than previously thought. The length–weight relation
of A. glacialis is similar across the European Arctic. 相似文献
18.
Ragnhild Pettersen Geir Johnsen J?rgen Berge Erlend Kjeldsberg Hovland 《Polar Biology》2011,34(5):627-635
Phytoplankton pigment signatures from a cruise in 2005 are herein presented and used as a chemotaxonomic tool for phytoplankton
diversity in the Svalbard marine archipelago. Studies from these waters have until recently reported only a few groups of
phytoplankton, and while this paper is the first to show that the diversity around Svalbard includes all major phytoplankton
pigment groups, the results are seen in relation to other similar studies from the Arctic. We present two potentially important
marker pigments: prasinoxanthin, originating from prasinophytes, and gyroxanthin-diester, possibly originating from the temperate-
and bloom-forming coccolithophore Emiliania huxleyi. Pigment identification by HPLC revealed a significant amount of Chlorophyll b-containing chlorophyceae, euglenophyceae and prasinophyceae. Prasinoxanthin was present at 50% of the examined stations,
typically at Chl a maximum (15–25 m depth), in both Atlantic and Arctic water masses. Gyroxanthin-diester, in contrast to prasinoxanthin, was
found only in Atlantic water masses and at low concentrations. Our data may be important for the identification and verification
of remotely sensed images of different pigment groups of phytoplankton and their corresponding biomass, typically estimated
from Chl a. Remotely sensed presence of coccoliths, indicating E. huxleyi at sea surface, is discussed in relation to water masses and pigment signatures at sea surface and Chl a maximum depths. 相似文献
19.
Bacterial carbon demand, an important component of ecosystem dynamics in polar waters and sea ice, is a function of both bacterial
production (BP) and respiration (BR). BP has been found to be generally higher in sea ice than underlying waters, but rates
of BR and bacterial growth efficiency (BGE) are poorly characterized in sea ice. Using melted ice core incubations, community
respiration (CR), BP, and bacterial abundance (BA) were studied in sea ice and at the ice–water interface (IWI) in the Western
Canadian Arctic during the spring and summer 2008. CR was converted to BR empirically. BP increased over the season and was
on average 22 times higher in sea ice as compared with the IWI. Rates in ice samples were highly variable ranging from 0.2
to 18.3 μg C l−1 d−1. BR was also higher in ice and on average ~10 times higher than BP but was less variable ranging from 2.39 to 22.5 μg C l−1 d−1. Given the high variability in BP and the relatively more stable rates of BR, BP was the main driver of estimated BGE (r
2 = 0.97, P < 0.0001). We conclude that microbial respiration can consume a significant proportion of primary production in sea ice and
may play an important role in biogenic CO2 fluxes between the sea ice and atmosphere. 相似文献
20.
The sea anemone Bathyphellia margaritacea (Danielssen in Actinida. The Norwegian North-Atlantic expedition 1876–1878, Groendahl, Oslo, 1890) was collected by the research
submersible MIR at the North Pole at a depth of 4,262 m and by the North Pole Drifting Station NP-22 in the American sector
of Arctic Ocean covered by permanent ice. These widely separated records significantly increase the known geographic range
of the species. B. margaritacea is highly plastic and has an ability to occupy different types of substrates. It appears to be the only species of sea anemone
that is able to range in the high Arctic up to the North Pole and the only reliably identified species known from this part
of the world. 相似文献