Microbial community structure in the marginal ice zone of the Bellingshausen Sea
In: Journal of Marine Systems. Elsevier: Tokyo; Oxford; New York; Amsterdam. ISSN 0924-7963; e-ISSN 1879-1573, more
Also appears in:Le Fèvre, J.; Tréguer, P. (Ed.) (1998). Carbon Fluxes and Dynamic Processes in the Southern Ocean: Present and Past. Selected papers from the International JGOFS Symposium, Brest, France, 28-31 August 1995. Journal of Marine Systems, 17(1-4). Elsevier: Amsterdam. 1-619 pp., more
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| Keywords |
Organic matter > Particulates > Particulate organic matter > Organic carbon > Particulate organic carbon
Population characteristics > Biomass
PSW, Bellingshausen Sea
Marine/Coastal |
| Authors | | Top |
- Edwards, E.S.
- Burkill, P.H.
- Sleigh, M.A.
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| Abstract |
Phytoplankton, bacteria and microzooplankton were investigated on a transect in the Bellingshausen Sea during the ice melt period in November–December 1992. The transect along the 85°W meridian comprised seven stations that progressed from solid pack-ice (70°S), through melting ice into open water (67°S). The abundance, biomass and taxonomic composition were determined for each component of the microbial community. The phytoplankton was mostly dominated by diatoms, particularly small (<20 μm) species. Diatom abundance ranged from 66 000 cells l−1 under the ice to 410 000 cells l−1 in open water. Phytoplankton biomass varied from <1 to 167 mg C m−3, with diatoms comprising 89–95% of the total biomass in open water and autotrophic nanoflagellates comprising 57% under the ice. The standing stocks of autotrophs in the mixed layer ranged from 95 mg C m−2 under the pack-ice to 9478 mg C m−2 in open waters. Bacterial abundance in ice-covered and open water stations varied from 1.1 to 5.5×108 cells l−1. Bacterial biomass ranged from 2.4 mg C m−3 under pack-ice to an average of 14 mg C m−3 in open water. The microzooplankton consisted mainly of aloricate oligotrich ciliates and heterotrophic dinoflagellates and these were most abundant in open waters. Their biomass varied between 0.2 and 54 mg C m−3 with a minimum at depth under the ice and maximum in open surface waters. Microheterotrophic standing stocks varied between 396 mg C m−2 under pack-ice and 3677 mg C m−2 in the open waters. The standing stocks of the total microbial community increased consistently from 491 mg C m−2 at the ice station to 13 155 mg C m−2 in open waters, reflecting the productive response of the community to ice-melt. The composition of the microbial community also shifted markedly from one dominated by heterotrophs (82% of microbial stocks) at the ice station to one dominated by autotrophs (73% of microbial stocks) in the open water. Our estimates suggest that the microbial community comprised >100% of the total particulate organic carbon (POC) under the ice and 62–66% of the measured POC in the open waters. |
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