Summer-winter differences in copepod distribution around South Georgia
Atkinson, A.; Ward, P. (1988). Summer-winter differences in copepod distribution around South Georgia, in: Boxshall, G.A. et al. Biology of copepods: Proceedings of the third international conference on Copepoda. Developments in Hydrobiology, 47: pp. 325-334. http://dx.doi.org/10.1007/978-94-009-3103-9_33 In: Boxshall, G.A.; Schminke, H.K. (Ed.) (1988). Biology of copepods: Proceedings of the third international conference on Copepoda. Developments in Hydrobiology, 47. Kluwer Academic Publishers: Dordrecht/Boston/London. ISBN 978-94-010-7895-5; e-ISBN 978-94-009-3103-9. XII, 639 pp. https://dx.doi.org/10.1007/978-94-009-3103-9, more In: Dumont, H.J. (Ed.) Developments in Hydrobiology. Kluwer Academic/Springer: The Hague; London; Boston; Dordrecht. ISSN 0167-8418, more |
| Keywords | Aquatic communities > Plankton > Zooplankton
Periodicity > Seasonality
Copepoda [WoRMS]
Antarctica [Marine Regions]; South Georgia
Marine/Coastal | | Author keywords | |
| Abstract | Zooplankton was sampled on a synoptic grid of stations centered on South Georgia during the austral summer of 1981/82 and winter 1983. Within the top 1000 m layer at oceanic stations, copepods averaged 48% of the total biomass in summer and winter, but outnumbered all other taxa combined by a factor of 10. In winter the mean zooplankton biomass within the top 1000 m was 68% of its summer level. Copepod biomass was 77% of its summer level. During both surveys, the large and abundant Calanoides acutus and Rhincalanus gigas dominated the copepod biomass and. with several other species, showed a marked downwards seasonal migration out of the top 250 m layer in winter. Antarctic epipelagic species predominated around the island during summer but tended to be replaced by sub-Antarctic and cosmopolitan species during the winter. Factors likely to influence our estimates of overall copepods abundance and changes in species composition include seasonality of reproduction, net mesh selection and differences in water mass distribution. The observed trends are attributed mainly to variation in the position of the Polar Front which lay north of the island during the summer survey yet lay across the survey area in winter. This resulted in a greater influence of sub-Antarctic water around South Georgia in winter and the displacement of Antarctic species. |
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