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1.
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
2.
Nitrogen uptake in the infiltration community, an ice algal community in Antarctic pack-ice 总被引:1,自引:0,他引:1
S. Kristiansen T. Farbrot H. Kuosa S. M. Myklestad C. H. von Quillfeldt 《Polar Biology》1998,19(5):307-315
An infiltration community was the dominating ice algal community in pack-ice off Queen Maud Land, Southern Ocean, in January
1993. The community was dominated by autotrophic processes, and the most common species were the prymnesiophyte Phaeocystis antarctica and the diatoms Chaetoceros neglectus and Fragilariopsis cylindrus. The concentration of chlorophyll a was 1.3–47.9 μg l−1, and the inner part of the community was nitrate depleted. Uptake rates of nitrate, nitrite, ammonium, urea and amino acids
were measured using 15N. Nitrate was the major nitrogen source for ice algal growth (67 ± 6% nitrate uptake). It is suggested that % nitrate uptake
in the infiltration community decreases during the growth season, from 92% during spring (literature data) to 67% during summer.
Scalar irradiance in the infiltration community was high and variable. It reached ca. 2000 μmol m−2 s−1 at some locations, and nitrate uptake rate was potentially photoinhibited at irradiances >500 μmol m−2 s−1. Nitrate uptake rate in an average infiltration community (0.6 m of snow cover) was lowered by 13% over a 2-week period due
to photoinhibition.
Received: 16 December 1996 / Accepted: 5 January 1998 相似文献
3.
Overwintering populations of Mesodinium rubrum (Ciliophora: Haptorida) in lakes of the Vestfold Hills, East Antarctica 总被引:1,自引:0,他引:1
J. A. E. Gibson Kerrie M. Swadling Tracey M. Pitman Harry R. Burton 《Polar Biology》1997,17(2):175-179
The autotrophic ciliate Mesodinium rubrum Lohmann was observed during winter and spring in saline lakes ranging in salinity from 2 to 78‰ in the Vestfold Hills, Antarctica.
The ciliate remained active during winter, and contained chlorophyll even though the level of light available for photosynthesis
was minimal. No evidence of encystment as a means of survival during winter was observed. A seasonal study in one of the lakes,
Ace Lake, revealed that M. rubrum was present throughout the year at abundances ranging from 1×104 to 3.5×105 cells l-1. During the winter period, when little light penetrated the lake’s ice cover, cells were most common immediately under the
ice at 2 m, where cell numbers were typically 8×104 cells l-1.
Received: 3 January 1996/Accepted: 21 April 1996 相似文献
4.
Barbara Urban-Malinga Aleksander Drgas Anetta Ameryk Agnieszka Tatarek 《Polar Biology》2009,32(2):243-252
Intertidal meiobenthos of Hornsund—the southernmost fjord of Spitsbergen—was investigated between July and September 2005.
Mean total meiofaunal densities ranged between 4.3 and 328 ind. 10 cm−2. Nematode assemblages were impoverished in terms of the number of genera when compared with those from the western Spitsbergen
coast (11 vs. 25–28 genera in total, respectively). It is suggested that severe environmental conditions in the southern part
of Spitsbergen overcome the adaptation skills of many nematode species and hamper the establishment of a diverse community.
Comparatively high nematode numbers on a beach subject to heavy macroalgal wrack input contrast sharply with numerically poor
communities in sparse-wrack beaches (up to 315 vs. 31 ind. 10 cm−2, respectively). It is suggested that the wrack input to the Arctic beach may substantially influence the richness and composition
of the intertidal meiobenthic community. Nematode assemblages were dominated by extreme colonizers: Geomonhystera disjuncta and rhabditids. Their relatively high densities in beach sediments recorded at the beginning of July indicate their ability
to recover rapidly after the winter period and to effective (re)colonization of the intertidal habitat just after the ice
melt. Average concentration of rhabditids and monhysterids associated with macroalgal wrack deposited on the upper shore was
as high as 52 × 103 individuals per gram of the substrate. It is hypothesized that nematodes can play a substantial role in the wrack decomposition
in the Arctic intertidal. 相似文献
5.
This is the first study to determine vertical distribution patterns of sympagic meiofauna, including metazoans, protozoans
and eggs >20 μm, in the Amundsen Gulf (southeastern Beaufort Sea, Arctic). Full sea-ice cores were sampled from mid of March
to end of May 2008 (Circumpolar Flaw Lead system study). Investigations were performed on first-year ice from three pack-
and three fast-ice stations. Additionally, 5-cm bottom-ice sections were sampled at 13 pack-ice and 5 fast-ice stations. The
metazoan community was composed of nematodes, rotifers, copepods, copepod nauplii, platyhelminthes and a few rare taxa such
as mollusks, cnidarians and nemerteans. High numbers of eggs, between 50 and 2,188 eggs L−1, particularly of nematodes and copepods, were present in the ice. Investigations revealed also eggs of the pelagic species
Calanus hyperboreus and Sagitta spp. within the ice, so that further research is needed to clarify whether more organisms than expected might use this habitat
as a reproduction ground. Many different morphotypes of protozoans were observed in the samples, especially ciliates of the
order Euplotida. The highest abundance was always found in the lowermost 5 cm of the ice cores, nevertheless sympagic meiofauna
was not restricted to that part of the ice. Integrated meiofauna abundance ranged between 41 and 4,738 × 102 Ind. m−2 and was highest in the fast ice in early May. Differences between pack and fast ice in terms of integrated meiofauna communities
and vertical distribution were not significant, while the analysis of the bottom-ice sections indicated both a temporal development
and ice-type-specific differences. 相似文献
6.
Preliminary investigation of Okhotsk Sea ice algae; taxonomic composition and photosynthetic activity 总被引:1,自引:1,他引:0
Okhotsk Sea pack ice from Shiretoko in northern Hokkaido, sampled in March 2007, contained microalgal communities dominated
by the centric diatoms Thalassiosira
nordenskioeldi and T. punctigera. Domination by this genus is very unusual in sea ice. Communities from nearby fast ice at Saroma-ko lagoon were dominated by Detonula conferavea and Odontella aurita. Average microalgal biomass of the Okhotsk Sea pack ice (surface and bottom) was 1.59 ± 1.09 μg chla l−1 and for fast ice (bottom only) at nearby Saroma-ko lagoon, 16.5 ± 3.2 μg l−1 (=31.1 ± 5.0 mg chla m−2). Maximum quantum yield of the Shiretoko pack ice algal communities was 0.618 ± 0.056 with species-specific data ranging
between 0.211 and 0.653. These community values are amongst the highest recorded for sea ice algae. Rapid light curves (RLC) on individual cells indicated maximum relative electron transfer rates (relETR) between 20.8 and
60.6, photosynthetic efficiency values (α) between 0.31 and 0.93 and onset of saturation values (E
k) between 33 and 91 μmol photons m−2 s−1. These data imply that the pack ice algal community at Shiretoko was healthy and actively photosynthesising. Maximum quantum
yield of the Saroma-ko fast ice community was 0.401 ± 0.086, with values for different species between 0.361 and 0.560. RLC
data from individual Saroma-ko fast ice algal cells indicated relETR between 55.3 and 60.6, α values between 0.609 and 0.816
and E
k values between 74 and 91 μmol photons m−2 s−1 which are consistent with measurements in previous years. 相似文献
7.
Vertical distribution of bacteria in Arctic sea ice from the Barents and Laptev Seas 总被引:5,自引:0,他引:5
The vertical distribution of bacterial abundance and biomass was investigated in relation to algal biomass in ice cores taken
from drifting ice floes in two Arctic shelf areas: the Barents Sea and the Laptev Sea. Bacteria were not homogeneously distributed
throughout the cores but occurred in dense layers. Different types of distribution patterns were found: either a single maximum
occurred inside or at the bottom of the ice floe or maxima were found in different parts of the floes. Bacterial concentrations
ranged from 0.4 to 36.7 · 105 cells ml−1. The size spectra of sea-ice bacteria were determined by image analysis. Cell sizes showed considerable variation between
the ice floes. In multi-year sea ice, the largest bacteria were observed in the area of an internal chlorophyll a maximum. No specific vertical distribution patterns were found in first-year ice floes. Bacterial biomass for the ice cores
ranged from 19.2 to 79.2 mg C m−2, and the ratio of bacterial:ice algal biomass ranged from 0.43 to 10.42. A comparison with data collected from fast ice revealed
large differences in terms of cell size, abundance and biomass.
Received: 7 September 1995 / Accepted: 10 September 1996 相似文献
8.
A. McMinn 《Polar Biology》1996,16(4):301-307
Algae released from fast-ice in Ellis Fjord, eastern Antarctica, made little contribution to subsequent phytoplankton growth.
Dominant taxa in the interior ice community included Nitzschia cylindrus (Grun) Hasle, Navicula glaciei V.H. and a dinoflagellate cyst. Diatom mortality within the ice was high. The algal contribution to the phytoplankton from
the fast ice was estimated by calculating the difference between algal biomass in ice cores taken on 14 November with those
taken on 18 December 1992. The biomass of sedimenting phytoplankton was estimated using sediment traps; weekly cell counts
of water were used to monitor net phytoplankton growth. The low contribution from the fast-ice of Ellis Fjord to the phytoplankton
is similar to results from other Antarctic fast-ice communities but is not necessarily reflective of processes occurring within
either Antarctic or Arctic pack ice communities. An algal mat growing on the base of the fast-ice had a carbon standing crop
of between 0.231 gC m-2 and 0.022 gC m-2. Much of this was delivered to the water column as the ice melted while the remainder was exported.
Received: 15 March 1995/Accepted: 4 September 1995 相似文献
9.
Twenty-two stations in the intertidal and shallow sublittoral of Bjornoya (74 °N, 19 °E) were studied in August 1994 revealing
a large and diverse standing crop of macro-algae (16 species) and littoral macrofauna (at least 17 species). In most places
the biomass of littoral macroorganisms exceeded 100 g ww/m2. In the shallow sublittoral, between 2 and 20 m, 45 animal taxa and 23 algae species were collected. Littoral coarse sand
meiofauna was dominated by Turbellaria, while, on algae, Halacaridae and Harpacticoida predominated. Meiofauna densities ranged
from 0 to 169 ind./10 cm2 and biomass from 0 to 0.4 g dw/m2. The abundance of littoral species and their zoogeographic origin resemble that of Spitsbergen more than that of the northern
Scandinavian coast, although both are of equal distance from Bjornoya. The first record of the boreal bivalve Mytilus edulis from the island is presented. Another striking feature was the presence of the arctic amphipod Gammarus setosus and the absence of its boreal sibling species G.oceanicus.
Received: 19 March 1996 / Accepted: 1 December 1996 相似文献
10.
Timothy D. Siferd Harold E. Welch Martin A. Bergmann Martin F. Curtis 《Polar Biology》1997,18(1):16-22
The seasonal distribution of sympagic amphipods was investigated in the Chesterfield Inlet area of northwestern Hudson Bay
(63°30′N). Amphipod abundance was measured by photographic samples and species composition was determined by sweep net samples.
Twelve species of amphipods were collected, the most common being Ischyrocerus anguipes, Pontogeneia inermis, Apherusa megalops and Weyprechtia pinguis. The major environmental variable affecting amphipod distribution was water depth. Amphipod abundance was highest near 20
m and near zero past 50 m. The maximum recorded abundance was 1367 m−2. A minor factor affecting the distribution of amphipods was snow depth, through its modifying effect on light and thereby
the growth of ice algae. Amphipods began to inhabit the sea ice shortly after its formation. From the beginning of March,
the number of amphipods on the ice increased steadily to about the 3rd week of April, after which numbers declined. This pattern
coincided with the seasonal ice algae abundance. Amphipods reduced ice algal biomass over 20-m depth by 63%. No evidence of
diurnal changes in abundance was observed.
Received: 15 May 1996 / Accepted: 4 November 1996 相似文献
11.
The epilithic biomass of an outflow stream at Potter Peninsula (King George Island, Antarctica) was studied from November
1996 to February 1997 by means of chlorophyll a concentration, dry weight and ash-free dry weight. The Autotrophic Index and the Lakatos classification were also used in
order to characterize the epilithic community. Several physical and chemical parameters were analyzed. Snow and ice melt greatly
increased water flow through Tres Hermanos Lake and in the stream. Chlorophyll a concentrations fluctuated between undetectable and 3.5 μg cm−2 with a marked increase, which averaged 3 orders of magnitude, towards the end of the study period. Dry weight ranged between
299.9 and 13,118.7 μg cm−2 and ash-free dry weight between 70.8 and 996.9 μg cm−2. According to the Autotrophic Index and the Lakatos classification, the epilithon of the stream had a low mass with low organic
component and large amount of inorganic sediment. The organic matter comprised a low proportion of chlorophyll a and a major proportion of probably detritus or bacteria, rather than fauna.
Accepted: 3 June 2000 相似文献
12.
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
13.
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
14.
D. A. Wharton N. B. To 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(5):344-349
The freezing and freezing survival of the Antarctic nematode Panagrolaimus davidi after exposure to solutions of different osmotic concentrations has been examined using a thermoelectric cooling stage and
multi-specimen cooling block to see if there is any evidence that freeze-induced desiccation prevents inoculative freezing.
The nematodes froze in all the test solutions used (up to 1138 mosmol ⋅ l-1) and at all cooling rates and nucleation temperatures tested. Freezing survival was at its maximum in 0.1 mol ⋅ l-1 NaCl in artificial tap water after 1 h exposure to the test solution and in artificial tap water after 24 h exposure. Hyperosmotic
and hyposmotic stress adversely affected the nematodes’ ability to survive freezing. In non-frozen controls survival declined
with increasing osmolality of the test solution. Measurements of the osmolality of water extracted from a variety of moss
samples indicate that the nematodes are exposed to an osmotic concentration of about 9 mosmol ⋅ l-1 in their natural habitat. This is close to that of artificial tap water. Our experiments, and measurements of freeze concentration
effects in the literature, indicate that freeze-induced desiccation is unlikely to prevent inoculative freezing and the survival
of nematodes over the winter.
Accepted: 5 May 1996 相似文献
15.
The key to taking the measure of biodiversity lies in a downward adjustment of scale. . .Most of the Earth’s largest species—mammals,
birds, and trees—have been seen and documented. But microwildernesses exist in a handful of soil or aqueous silt collected
almost anywhere in the world. . .Bacteria, protistans, nematodes, mites and other minute creatures swarm all around us, an
animate matrix that binds the Earth’s surface. Edward O Wilson (1994. Naturalist. Island Press, Washington, DC)
Received 11 March 1996/ Accepted in revised form 04 September 1996 相似文献
16.
Annual variations in nutrients, algal biomass, and primary production were investigated in Lake Ohnuma, Japan, in 1996 in
order to compare them with 1977. Chlorophyll a concentrations gradually increased after the ice melted and reached a maximal value of 20.7 μg l−1 in August. Phosphate concentrations in the lake were close to the detection limit throughout the study period, whereas sufficient
nitrate remained even in the productive summer season. In contrast, in the summer of 1977, both nutrients were exhausted,
and primary production was less than 0.2 g C m−2 day−1. Primary production in 1996 ranged from 0.4 to 5.8 g C m−2 day−1, which was 2 to 30 times higher than 20 years ago. These results indicate that the lake has become eutrophic in the last
two decades. A comparison of the nutrients in the inflowing river between 1977 and 1996 indicated that nitrate and ammonium
concentrations were markedly elevated in the rivers, and therefore the nitrogen loading to the lake tripled.
Received: March 1, 1999 / Accepted: October 18, 1999 相似文献
17.
M. B. Cassidy K. W. Shaw H. Lee J. T. Trevors 《Applied microbiology and biotechnology》1997,47(2):108-113
A pentachlorophenol(PCP)-degrading Pseudomonas sp. strain UG30 was encapsulated in κ-carrageenan for use in PCP degradation. Free and encapsulated cells were compared for
their ability to dechlorinate and mineralize 100–800 μg/ml sodium pentachlorophenate in broth. Dechlorination was measured
with a chloride ion electrode, and mineralization was measured by 14CO2 evolution from radiolabelled [U-14C]PCP. Free and encapsulated Pseudomonas sp. UG30 cells mineralized up to 200 μg/ml and 600 μg/ml PCP, respectively, after 21 days. Encapsulation of UG30 cells provided
a protective effect, allowing dechlorination and mineralization of high levels of PCP to occur.
Received: 3 May 1996 / Received revision: 4 September 1996 / Accepted: 13 September 1996 相似文献
18.
During January 1989, phytoplankton biomass and species composition were studied in a north / south transect at the Weddell / Scotia
Confluence (47°W), between 57° and 61°30′S. Results showed a diatom bloom in the Scotia Sea (chlorophyll a 1.9 μg l−1, particulate organic carbon 239 μg l−1), dominated by Fragilariopsis cylindrus, Dactyliosolen antarcticus and Chaetoceros dichaeta. Low chlorophyll a / phaeopigments ratios (about 1.4) and silicate concentrations (15 μmol l−1) suggested that this was an advanced bloom phase, probably linked to high grazing pressure. Minimum chlorophyll a values of 0.1–0.2 μg l−1 and particulate organic carbon 46 μg l−1 were found at the Weddell / Scotia Front and in a subsurface layer of the Weddell Sea Water. In the southern part of the
transect (61°30′S), in the Weddell Sea, a second surface maximum was found (chlorophyll a 0.9 μg l−1, particulate organic carbon 120 μg l−1), but with a different species composition, with Cryptomonas sp. dominant. Our results show a succession within the diatom community in the Weddell / Scotia Confluence Waters when comparing
the three EPOS legs. In the Weddell Sea from spring to summer, nanoflagellates, with only a minor contribution from diatoms,
persist over a long period with little change in the community structure. We suggest that the frontal system, together with
the receding ice edge and the grazing pressure of either krill or protozooplankton, are mainly responsible for the phytoplankton
distribution patterns found.
Received: 3 July 1996 / Accepted: 3 November 1996 相似文献
19.
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
20.
K. Scheibner M. Hofrichter A. Herre J. Michels W. Fritsche 《Applied microbiology and biotechnology》1997,47(4):452-457
Within a screening program, 91 fungal strains belonging to 32 genera of different ecological and taxonomic groups (wood-
and litter-decaying basidiomycetes, saprophytic micromycetes) were tested for their ability to metabolize and mineralize 2,4,6-trinitrotoluene
(TNT). All these strains metabolized TNT rapidly by forming monoaminodinitrotoluenes (AmDNT). Micromycetes produced higher
amounts of AmDNT than did wood- and litter-decaying basidiomycetes. A significant mineralization of [14C]TNT was only observed for certain wood- and litter-decaying basidiomycetes. The most active strains, Clitocybula dusenii TMb12 and Stropharia rugosa-annulata DSM11372 mineralized 42 % and 36 % respectively of the initial added [14C]TNT (100 μM corresponding to 4.75 μCi/l) to 14CO2 within 64 days. Micromycetes (deuteromycetes, ascomycetes, zygomycetes) proved to be unable to mineralize [14C]TNT significantly.
Received: 8 August 1996 / Received revision: 16 December 1996 / Accepted: 20 December 1996 相似文献