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>Plankton dynamics in the marginal ice zone of the central Barents Sea during spring: carbon flow and structure of the grazer food chain
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Plankton dynamics in the marginal ice zone of the central Barents Sea during spring: carbon flow and structure of the grazer food chain
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机译：Plankton dynamics in the marginal ice zone of the central Barents Sea during spring: carbon flow and structure of the grazer food chain
Plankton community structure was analysed during spring at four stations along a transect from the polar ice into open waters of the Barents Sea. The transect mimicks a time span of months in the biological succession during the Arctic summer. The significance of the microbial food web vs the more classical food web was evaluated using carbon budget models. The standing stocks of diatom-dominated phytoplankton and bacteria were generally high especially in connection to ice. The biomass of microzooplankton, dominated by heterotrophic dinoflagellates was significantly high, with specific growth rates following the in situ temperature. The mean ± SE specific growth rate was 0.40±0.12 d−1for ciliates and 0.24 ± 0.05 d−1for heterotrophic dinoflagellates, indicating no food limitation. The estimated total carbon requirement for microzooplankton was, at the ice-covered station, approximately 100 of the daily primary production, decreasing to 25 in the open water. Carbon-specific secondary production of the copepodsCalanus finmarchicus(Gunnerus),C. glacialis(Jaschnov),C. hyperboreus(Krøyer) andMetridia longa(Lubbock) were analysed by egg production.C. finmarchicusandM. longawere productive at all stations, including the ice-covered locations, with a maximum at 0.08 d−1and 0.035 d−1, respectively. The other, more Arctic-related,Calanusspp. were virtually outspawned. The standing stock of copepods was only 10–20 of the total microbial grazer biomass. The community growth and grazing by copepods showed significantly less quantitative importance for the pelagic carbon flow than the microb
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