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1.
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
2.
Hans Mose Jensen Lorna Pedersen AnnDorte Burmeister Benni Winding Hansen 《Polar Biology》1999,21(5):269-278
The distribution of phytoplankton biomass and primary production were studied during summer 1993 at 16 stations from 65 to
72°N off West Greenland, ranging more than 900 km. Hydrography, nutrients and chlorophyll a profiles revealed a significant change in structure from south to north. Nitrate was depleted in the euphotic zone at most
stations except close to the ice edge (West Ice) or close to outflow from large glaciers. The vertical distribution of phosphate
followed that of nitrate, but was never depleted. Despite two stations with relatively high surface concentrations, silica
showed the same distribution as the other two nutrients. In the south, chlorophyll a concentration and primary production were lower than north of Disko Bay (69°N), associated with a well-mixed versus a salinity-generated
stratification, respectively. In Vaigat, a high-production station was identified, (st. 910, 69°52′69N–51°30′61W) with a chlorophyll a concentration in the euphotic zone of >13 μg l−1 and an area primary production of 3.2 g C m−2 day−1. This is seldom encountered in arctic waters and was presumably due to nutrient-rich melt-water originating from the Iluliíssat
Glacier. The overall primary production for the studied area was 67–3207 mg C m−2 day−1 (mean ± SD=341± 743 mg C m−2 day−1), which is within the range of the few results published for West Greenland and eastern Canadian Arctic waters.
Accepted: 24 October 1998 相似文献
3.
Epibenthic brittle star assemblages were investigated on the northwestern Barents Sea shelf between 81° and 77°N in July
1991. At 9 drift stations in water depths between 80 and 360 m, series of 35–71 photographs, each depicting about 1 m2 of the seabed, were taken along transects of about 150- to 300-m length to assess abundances and spatial distribution patterns
of adult brittle stars (disc diameter ≥1 mm). Biomass values were derived by combining abundances with size-weight relationships
and size frequencies established using specimens from trawl catches. Six brittle star species were identified on the seabed
images. Ophiocten sericeum was the most abundant species on shallow shelf banks (≤100 m). Up to 2,800 individuals were counted on a single photograph;
median abundances per station ranged from 32 to 524 ind.m-2 and biomass from 0.3 to 5.0 g ash-free dry weight (AFDW) m-2. The spatial distribution along the transects (i.e. on the 100-m scale) was, however, extremely patchy. Disc diameters of
O. sericeum ranged between 1.6 mm and 15.4 mm. In deeper shelf habitats (>150 m), O. sericeum was rare or absent, and Ophiacantha bidentata dominated the brittle star fauna with median densities and biomasses of 2–49 ind.m-2 and 0.07–1.9 g AFDW m-2, respectively. Its disc diameters ranged from 2.9 to 14.4 mm. The other species (Ophiura sarsi, Ophiopholis aculeata, Ophioscolex glacialis, Ophiopleura borealis) occurred in distinctly lower numbers. Our findings provide further evidence that brittle stars dominate epibenthic communities
on Arctic shelves and locally reach very high abundances. Dense beds of Ophiocten sericeum seem to be a general phenomenon on high-Arctic shallow shelf banks.
Received: 30 March 1995/Accepted: 30 June 1995 相似文献
4.
Phytoplankton biomass and productivity were measured during two cruises in the Bransfield Strait in December 1991 (D91) and
January/February 1993 (J93). Strong seasonal variability in productivity values was observed due to differences in the physiological
response of phytoplankton. However, although the photosynthetic capacity of phytoplankton was markedly lower in D91 [P
m
B
=0.61 ± 0.25 mg C (mg Chla)−1 h−1] than in J93 [P
m
B
=2.18 ± 0.91 mg C (mg Chla)−1 h−1], average water column chlorophyll values in different areas of the strait were approximately similar in D91 (49–78 mg Chla
m−2) and J93 (22–76 mg Chla m−2). The spatial distribution of chlorophyll was patchy and generally associated with the influence of the different water masses
that meet together in the Bransfield Strait. No correlation was found between the mixed layer depth and either the integrated
chlorophyll or the productivity. Our results suggest that major phytoplankton blooms in the Bransfield Strait are advected
from the nearby Gerlache Strait or Bellingshausen Sea following the main eastward surface currents.
Accepted: 5 July 1998 相似文献
5.
Mesozooplankton assemblages in the shallow Arctic Laptev Sea in summer 1993 and autumn 1995 总被引:2,自引:0,他引:2
Mesozooplankton distribution and composition in the very shallow part of the Siberian Laptev Sea shelf were studied during
the German-Russian expeditions “Transdrift I” (August/September 1993) and “Transdrift III” (October 1995). Maximum abundances
were found close to the outflow of the Lena River (7,965 ind. m−3) and in the Yana river mouth (38,163 ind. m−3). Lowest abundances occurred in the northeast and west of the Laptev Sea (64–95 ind. m−3). Highest biomass values (104–146 mg DM m−3) were determined in the northern and northeastern part of the shallow Laptev Sea, as well as close to the river outflows,
with a record biomass maximum in the Yana river mouth (270 mg DM m−3). Biomass minima were situated north of the Lena Delta and in the western part of the shallow Laptev Sea (0.3–1.0 mg DM m−3). Copepods dominated in terms of abundance and biomass. Cluster analyses separated four mesozooplankton assemblages: the
assemblage “Lena/Yana” in the southern part, “Eastern-central” in the centre, “Kotelnyy” in the eastern part and “Taimyr”
in the western part of the shallow Laptev Sea. The small-sized neritic and brackish-water copepods Drepanopus bungei, Limnocalanus grimaldii and Pseudocalanus major occurred in enormous numbers and made up the bulk of zooplankton abundance and biomass in the very shallow part of the Laptev
Sea close to the rivers Lena and Yana. In the more northern and northeastern areas, Calanus glacialis, P. minutus and P. major were dominant copepod species, whereas Oithona similis and Acartia sp. became important in the western Laptev Sea. Appendicularians, as well as hydromedusae and the chaetognath Sagitta sp., contributed significantly to abundance and biomass, respectively, but not over the entire area studied. One can identify
taxon-specific distribution patterns (e.g. Sagitta predominated the biomass in a zone between the area heavily influenced by Lena/Yana and the offshore area to the north),
which differ from the patterns revealed by cluster analysis. Hydrographic features, especially the enormous freshwater inflow,
apparently determine the occurrence and formation of zooplankton aggregations. Extremely high numbers of small-sized neritic
and brackish-water copepods occurred locally, which were probably also supported by excellent feeding conditions. 相似文献
6.
During the expedition ARK XI-2 with RV Polarstern in September/October 1995, a transect of samples was taken off East Greenland from the shelf down to about 1800 m depth by
means of an epibenthic sledge and a giant box corer, in order to obtain information on epibenthic and endobenthic macrofauna.
Within the epibenthic sledge catches, the Cumacea were the most numerous taxon with 32,123 (always calculated for 1000 m)
specimens, followed by the Isopoda with 26,914 specimens, and Amphipoda with 20,900; Mysidacea and Tanaidacea were less important.
Amphipoda were the most numerous taxon on the shelf, while with increasing depth Isopoda and especially Cumacea became increasingly
important. Macrofauna analysed from the box-corer samples decreased in abundance with depth. The highest macrofaunal abundance
was found on the shelf, with 8128 ind. m−2 (200 m); below this depth, density decreased from ≈2000 ind. m−2 (at 800 m) to ≈800 ind. m−2 (2000 m). Peracarid crustaceans and polychaetes were, next to bivalves, the most frequent. Polychaetes clearly dominated
the shelf communities; their relative percentage decreased with increasing water depth while the relative percentage of Peracarida
increased simultaneously. Interestingly, the highest number of peracarids in the epibenthic-sledge samples was reported from
deep sea, while box-corer samples showed decreasing macrofaunal abundance with depth. The relative percentage of peracarids
in the box-corer samples increased with depth, while in absolute numbers, peracarids from these samples were also highest
on the shelf at about 200 m depth.
Accepted: 14 February 1999 相似文献
7.
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
8.
Toluene vapour removal in a laboratory-scale biofilter 总被引:4,自引:0,他引:4
A bench-scale biofilter with a 0.5-m high filter bed, inoculated with a toluene-degrading strain of Acinetobacter sp. NCIMB 9689, was used to study toluene removal from a synthetic waste air stream. Different sets of continuous tests were
conducted at influent toluene concentrations ranging over 0.1–4.0 g m−3 and at superficial gas velocities ranging over 17.8–255 m h−1. The maximum volumetric toluene removal rate for the biofilter (242 g m−3 h−1) was obtained at a superficial gas velocity of 127.5 m h−1 (corresponding to a residence time of 28 s) and a toluene inlet concentration of 4.0 g m−3. Under these operating conditions, toluene removal efficiency was only 0.238, which suggested that effective operation required
higher residence times. Removal efficiencies higher than 0.9 were achieved at organic loads less than 113.7 g m−3 h−1. A macro-kinetic study, performed using concentration profiles along the bioreactor, revealed this process was limited by
diffusion at organic loads less than 100 g m−3 h−1 and by biological reaction beyond this threshold.
Received: 10 October 1999 / Received revision: 15 February 2000 / Accepted: 18 February 2000 相似文献
9.
The sympagic (=ice-associated) amphipod Gammarus wilkitzkii usually lives attached to the underside of Arctic sea ice. During an expedition to the Greenland Sea in May/June 1997, high
numbers of this species were found in pelagic Rectangular Midwater Trawl catches (0–500 m water depth) in an ice-free area,
35–42 km away from the ice edge. The amphipods seemed to have maintained position in the water column for at least 4 days.
Mean biomass data (length: 2.9 cm, organic content: 73% dry mass), gut fullness (>50% in 85% of specimens) and sex ratio (females:males
= 1:1.5) of these amphipods were very similar to values for under-ice populations. Due to their relatively high body density
(mean: 1.134 g cm−3), the energy demand for swimming was assumed to be high. Measurements of oxygen consumption of swimming and resting amphipods
(8.8 and 4.0 J g wet mass−1 day−1, respectively) suggested that, from an energetic point of view, G. wilkitzkii would maintain position in an ice-free water column for the time period.
Accepted: 11 January 1999 相似文献
10.
11.
Phytoplankton biomass and primary production in the marginal ice zone of the northwestern Weddell Sea during austral summer 总被引:2,自引:0,他引:2
Myung Gil Park Sung Ryull Yang Sung-Ho Kang Kyung Ho Chung Jae Hyung Shim 《Polar Biology》1999,21(4):251-261
During the austral summer of 1995, distributions of phytoplankton biomass (as chlorophyll a), primary production, and nutrient concentrations along two north-south transects in the marginal ice zone of the northwestern
Weddell Sea were examined as part of the 8th Korean Antarctic Research Program. An extensive phytoplankton bloom, ranging
from 1.6 to 11.2 mg m−3 in surface chlorophyll a concentration, was encountered along the eastern transect and extended ca. 180 km north of the ice edge. The spatial extent
of the bloom was closely related to the density field induced by the input of meltwater from the retreating sea ice. However,
the extent (ca. 200 km) of the phytoplankton bloom along the western transect exceeded the meltwater-influenced zone (ca.
18 km). The extensive bloom along the western transect was more closely related to local hydrography than to the proximity
of the ice edge and the resulting meltwater-induced stability of the upper water column. In addition, the marginal ice zone
on the western transect was characterized by a deep, high phytoplankton biomass (up to 8 mg Chl a m−3) extending to 100-m depth, and the decreased nutrient concentration, which was probably caused by passive sinking from the
upper euphotic zone and in situ growth. Despite the low bloom intensity relative to the marginal ice zone in both of the transects,
mean primary productivity (2.6 g C m−2 day−1) in shelf waters corresponding to the northern side of the western transect was as high as in the marginal ice zone (2.1 g C m−2 day−1), and was 4.8 times greater than that in open waters, suggesting that shelf waters are as highly productive as the marginal
ice zone. A comparison between the historical productivity data and our data also shows that the most productive regions in
the Southern Ocean are shelf waters and the marginal ice zone, with emerging evidence of frontal regions as another major
productive site.
Accepted: 27 September 1998 相似文献
12.
The spring mesozooplankton community at South Georgia: a comparison of shelf and oceanic sites 总被引:3,自引:3,他引:0
Mesozooplankton (predominantly 200–2000 μm) were sampled at a shelf and an oceanic station close to South Georgia, South
Atlantic, during austral spring (October/November) 1997. Onshelf zooplankton biomass was extremely high at 10–16 g dry mass
m−2 (0–150 m), 70% comprising the small neritic clausocalaniid copepod Drepanopus forcipatus. Large calanoid species, principally Calanoides acutus and Rhincalanus gigas, contributed only 8–10%. At the oceanic station, biomass in the sampled water column (0–1000 m) was ∼6.5 g dry mass m−2 and 4–6 g dry mass m−2 in the top 200 m. Here, large calanoids composed 40–50% of the standing stock. Antarctic krill (Euphausia superba) occurred in low abundances at both stations. Vertical profiles obtained with a Longhurst Hardy Plankton Recorder indicated
that populations of C. acutus and R. gigas, which overwinter at depth, had completed their spring ascent and were resident in surface waters. Dry mass, carbon and lipid
values were lower than found in summer but were consistent with overwintered populations. Phytoplankton concentrations were
considerably higher at the oceanic station (2–3 mg chlorophyll a m−3) and increased over the time on station. In response to this, egg production of both large calanoid species and growth rates
of R. gigas approached those measured in summer. Onshelf phytoplankton concentrations were lower (<1 mg m−3), and low egg production rates suggested food limitation. Here phytoplankton rations equivalent to 6% zooplankton body C
would have been sufficient to clear primary production whereas at the oceanic station daily carbon fixation was broadly equivalent
to zooplankton carbon biomass.
Accepted: 25 April 1999 相似文献
13.
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
14.
Distribution of abundance, biomass, production and productivity of macrozoobenthos in the sub-Antarctic Magellan Province (South America) 总被引:3,自引:3,他引:0
Distribution of abundance, biomass, productivity and production of macrozoobenthos was investigated in four study areas in
the Magellan region (South Patagonian Ice-Field, Strait of Magellan, Beagle Channel, Continental Shelf). Using a Reineck box
corer and a multibox corer, a total of 277 quantitative benthos samples were taken at 78 stations in water depths between
8 and 1139 m during the Joint Chilean-German-Italian Magellan “Victor-Hensen Campaign” in 1994, the “Polarstern” expedition
ANT XIII/4 in 1996 and the Chilean expeditions “Cimar Fiordo II + III” in 1996 and 1997, respectively, on board RV “Vidal
Gormaz”. Mean abundance in the South Patagonian Ice-Field was significantly lower than in the Strait of Magellan and the Beagle
Channel. Biomass and abundance decreased clearly with depth (20–300 m to 700–1500 m: 3.9 gC m−2 to 0.6 gC m−2; 2832 ind. m−2 to 569 ind. m−2). Average abundance, biomass and production of the whole Magellan region are lower (2318 ind. m−2, 3.2 gC m−2, 0.62 gC m−2 year−1) than in the high Antarctic Weddell Sea. In the Magellan region, macrozoobenthos composition of abundance is mainly dominated
by polychaetes (56%), followed by arthropods (16%), echinoderms (10%) and molluscs (11%). Comparisons of our present results
with those of high Antarctic areas make it clear that the Magellan region has a transitional character.
Accepted: 21 December 1998 相似文献
15.
Martin Emil Blicher Lars Maltha Rasmussen Mikael Kristian Sejr Flemming Ravn Merkel S?ren Rysgaard 《Polar Biology》2011,34(8):1105-1116
The number of common eiders (Somateria
mollissima borealis) in west Greenland declined dramatically during the twentieth century, supposedly because of human activities. However, their
sensitivity to alternative drivers of variation, such as climate conditions, diseases or food availability, remains unstudied.
In this study, we describe prey availability and assess the trophic coupling between eiders and their macrobenthic prey in
a shallow inlet, Nipisat Sound; a key wintering habitat in the south-west Greenland Open Water Area. Macrobenthic species
abundance and biomass were studied, and annual production was estimated by an empirical model, including environmental characteristics,
fauna composition and individual biomass. In spring 2008, average macrozoobenthic abundance and biomass were 6,912 ind m−2 and 28.4 g ash-free dry mass (AFDM) m−2 (647 kJ m−2), respectively. Annual production was estimated at 13.9 g AFDM m−2 year−1 (317 kJ m−2 year−1). During the winters of 2008–2010, we monitored the number of common eiders (S. mollissima borealis) and king eiders (Somateria spectabilis) and observed a distinct peak in abundance during winter with up to 15.000 birds in Nipisat Sound. Based on physiological
costs of different activities in combination with the observed behavioural pattern, we obtained an estimate of the energy
required for eiders to balance their costs of living, which amounted to 58% of the estimated total annual production of macrobenthos
in Nipisat Sound. This result suggests that eider predation affects macrobenthic species composition and biomass and demonstrates
the potential importance of variations in prey availability for the population dynamics of eiders in Greenland. 相似文献
16.
17.
This study was aimed at determining the optimal depth and photon irradiance for growth of Sargassum fulvellum. Sampling and measurement of underwater irradiance were carried out at farms cultivating S. fulvellum at Wando, southwestern coast of Korea, from May 2004 to April 2005. Growth of thalli, underwater irradiance and photosynthetic
quantum yield were measured over a range of depths for three culture stages. During their nursery cultivation stage (Stage
I), length increase was greatest at 1.5 m depth (2.5 ± 0.2 cm), where the average midday irradiance over 28 days was 488 ± 58
μmol photons m−2 s−1. During the pre-main cultivation stage (Stage II), the greatest length increase occurred at 1 m depth (10.9 ± 0.1 cm) with
an average irradiance of 845 ± 169 μmol photons m−2 s−1. For the main cultivation stage (Stage III) of the alga, thalli showed maximal length growth in March and early April at
depths of 1–2 m and 3 m. These results suggest that growth at each cultivation stage of S. fulvellum could be controlled by depth of cultivation rope.
Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines. 相似文献
18.
Evidence for active microbial nitrogen transformations in sea ice (Gulf of Bothnia, Baltic Sea) in midwinter 总被引:5,自引:3,他引:2
Hermanni Kaartokallio 《Polar Biology》2001,24(1):21-28
Nutrient concentrations, chlorophyll-a, bacterial biomass and relative activity of denitrifying organisms were investigated from ice-core, brine and underlying
water samples in February 1998 in the Gulf of Bothnia, Baltic Sea. Examined sea ice was typical for the Baltic Sea; ice bulk
salinity varied from 0.1 to 1.6 psu, and in underlying water salinity was from 4.2 to 4.7 psu. In 2- to 3-months-old sea ice
(thickness 0.4–0.6 m), sea-ice communities were at the winter stage; chl-a concentrations were generally below 1 mg m−3 and heterotrophic organisms composed 7–20% of organism assemblage. In 1-month-old ice (thickness 0.2–0.25 m), an ice spring
bloom was already developing and chl-a concentrations were up to 5.6 mg m−3. In relation to low salinity, high concentrations of NH+
4, NO−
2, PO3+
4 and SiOH4 were found in the ice column. The results suggest that the upper part of ice accumulates atmospheric nutrient load during
the ice season, and nutrients in the upper 10–20 cm of ice are mainly of atmospheric origin. The most important biological
processes controlling the sea-ice nutrient status are nutrient regeneration, nutrient uptake and nitrogen transformations.
Nutrient regeneration is specially active in the middle parts of the 50- to 60-cm-thick ice and subsequent accumulation of
nutrients probably enhances the ice spring bloom. Nitrite accumulation and denitrifying activity were located in the same
ice layers with nutrient regeneration, which together with the observed significant correlation between the concentrations
of nitrogenous nutrients points to active nitrogen transformations occurring in the interior layers of sea ice in the Baltic
Sea.
Accepted: 12 June 2000 相似文献
19.
Composition and distribution of asteroid and ophiuroid assemblages were investigated by means of Agassiz trawl catches at
34 stations in 220- to 1,200-m depth in the Weddell Sea and at 17 stations in 90- and 830-m depth off Northeast Greenland.
A total of 86 species (48 sea stars, 38 brittle stars) were identified in the Weddell Sea whereas off Northeast Greenland
a total of 26 species (16 sea stars, 10 brittle stars) were recorded. In both study areas, brittle stars were numerically
more important than sea stars, and abundances generally decreased with water depths. Multivariate analyses revealed a conspicuous
depth zonation of sea and brittle stars off Greenland. Very high abundances of Ophiocten sericeum and Ophiura robusta characterized the assemblages on shallow shelf banks whereas in greater depths Ophiopleura borealis, Ophioscolex glacialis and Ophiacantha bidentata became dominant, albeit at significantly lower densities. Mass occurrences of brittle stars, such as those recorded on Greenlandic
shelf banks, have not been discovered in the Weddell Sea, where distinct assemblages were discriminated in deep shelf trenches
as well as on the eastern and southern shelf. Ophioplocus incipiens, Ophiurolepis martensi and Ophiurolepis brevirima were the most prominent species on the eastern shelf. Ophiacantha antarctica, Ophiurolepis gelida and Ophionotus victoriae on the southern shelf, and Ophiosparte gigas as well as the asteriod Hymenaster sp., in the shelf trenches. Overall, the Weddell Sea housed conspicuously more asterozoan species than the waters off Greenland.
Higher species diversity was also evident at both a regional and local scale, especially for the eastern Weddell Sea shelf.
However, because many species from the Weddell Sea are closely related, the Weddell Sea assemblages were not significantly
different from the Greenland ones in terms of taxonomic diversity and distinctness.
Received: 29 April 1996/Accepted: 10 June 1996 相似文献
20.
The community structure of mesozooplankton was investigated in Dolgaya Bay (southern Barents Sea), a subarctic fjord, using
a Juday net (0.168-mm mesh size) in July, 2008. A total of 39 species and higher taxa were found. Average abundance, biomass
and diversity (±standard error) were 153,403 ± 15,855 ind m−2, 570 ± 61 mg dry mass m−2, and 2.25 ± 0.09, respectively. Copepods were the most numerous species. The mesozooplankton communities were dominated by
omnivores (Oithona similis and Acartia spp.). Vertical distribution of the mesozooplankton was characterized by copepod dominance at each sampled layer. There were
no significant correlations among physical variables and biological parameters, except negative correlation for the mean biomass
and mean water temperature. 相似文献