Phytoplankton Biomass near a Receding Ice-Edge in the Ross Sea
Ice-edge zones have been hypothesized to be major sites of primary production and energy transfer within the Southern Ocean, and large biomass accumulations of upper-trophic-level organisms (birds and mammals) occur in these zones. However, few data exist to determine if these ice-edge regions support elevated levels of phytoplankton and enhanced rates of primary production. During 2 cruises on the USCGC Glacier in January-February, 1983, the chlorophyll distribution was measured in different areas of the Ross Sea. Our primary study area was located off the coast of southern Victorialand (76° 30′ S) in a region of receding pack-ice. We occupied 34 stations in a 100 × 300 km area of variable ice concentration. In comparison to control stations and previous data, chlorophyll levels were high, averaging 4.08 ± 1.46 mg chl-a m−3 at the depth of the chlorophyll maximum in the water column, and 128.2 ± 91.7 mg m−2 when integrated from the surface to 150 m. High surface chlorophyll levels appeared to be highly correlated with a stable surface layer at the edge of the receding ice-pack. At stations outside of the ice-edge bloom, stability at the surface was reduced and chlorophyll concentrations were markedly lower. Water column stability appeared to be a major factor in the initiation and maintenance of ice-edge phytoplankton blooms, and the roles of these blooms in the overall estimates of biogenic production and energy flux of the Southern Ocean need to be re-evaluated.
KeywordsBiomass Acetone Chlorophyll Phytoplankton Nitrite
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- Buckley JR, Gammelsrod T, Johannessen JA, Johannessen OM,Roed LP (1979) Upwelling: Oceanic structure at the edge of the arctic ice pack in winter. Science 203: 165–167Google Scholar
- El-Sayed SZ (1970) On the productivity of the Southern Ocean (Atlantic and Pacific sectors). In: Holdgate MW (ed) Antarctic Ecology, Academic, New York, pp 119–135Google Scholar
- El-Sayed SZ, Turner JT (1977) Productivity of the Antarctic and tropical-subtropical regions: a comparative study. In: Dunbar M (ed), Polar Oceans, Proc SCOR/SCAR Polar Oceans Conf. Montreal, pp 463–504Google Scholar
- Everson I (1977) The Living Resources of the Southern Ocean. FAO, RomeGoogle Scholar
- Hart TJ (1934) On the phytoplankton of the south-west Atlantic and Bellingshausen Sea. Discovery Rep 8: 3–268Google Scholar
- Holm-Hansen O, El-Sayed SZ; Franceschini GA, Cuhel RL (1977) Primary production and the factors controlling phytoplankton growth in the Southern Ocean. In: Llano GA (ed) Adaptations within Antarctic Ecosystems, Proceedings of the 3rd SCAR Symposium of Antarctic Biology, Smithsonian Inst, Washington, pp 11–50Google Scholar
- Laws RM (1977) The significance of vertebrates in the Antarctic marine ecosystem. In: Llano GA (ed) Adaptations within Antarctic Ecosystems, Proceedings of the 3rd SCAR Symposium of Antarctic Biology, Smithsonian Inst, Washington, pp 411–438Google Scholar
- Mackintosh NA (1974) Sizes of krill eaten by whales in the Antarctic. Discovery Rep 36: 157–178Google Scholar
- Marr JWS (1962) The natural history and geography of the Antarctic krill (Euphausia superba Dana). Discovery Rep 32: 33–464Google Scholar
- McRoy CP, Goering JJ (1974) The influence of ice on the primary productivity of the Bering Sea. In: Hood DW (ed) Oceangraphy of the Bering Sea pp 403–421Google Scholar
- Neshyba S (1977) Upwelling by icebergs. Nature 267:507–508 Niebauer HJ (1982) Wind and melt driven ocean circulation in a marginal sea ice edge frontal system: a numerical model. Cont Shelf Res 1: 49–98Google Scholar
- Zwalley HJ, Parkinson C, Carsey F, Gloersen P, Campbell WJ, Ramseier RO (1979) Antarctic sea ice variations 1973–1975 NASA Weather Climate Rev Paper 56 Washington, DCGoogle Scholar