South Georgia, Antarctica: a productive, cold water pelagic ecosystem
The South Georgia region is characterised by high biomass and productivity of phytoplankton, zooplankton and vertebrate predators. Important commercial fisheries have been based at the island since the late 1700s, initially exploiting seals and whales, and currently taking krill Euphausia superba an...
Main Authors: | , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Inter-Research
2001
|
Subjects: | |
Online Access: | http://nora.nerc.ac.uk/id/eprint/18364/ http://www.int-res.com/articles/meps/216/m216p279.pdf |
id |
ftnerc:oai:nora.nerc.ac.uk:18364 |
---|---|
record_format |
openpolar |
spelling |
ftnerc:oai:nora.nerc.ac.uk:18364 2023-05-15T13:45:12+02:00 South Georgia, Antarctica: a productive, cold water pelagic ecosystem Atkinson, A. Whitehouse, M.J. Priddle, J. Cripps, G.C. Ward, P. Brandon, M.A. 2001 http://nora.nerc.ac.uk/id/eprint/18364/ http://www.int-res.com/articles/meps/216/m216p279.pdf unknown Inter-Research Atkinson, A.; Whitehouse, M.J.; Priddle, J.; Cripps, G.C.; Ward, P.; Brandon, M.A. 2001 South Georgia, Antarctica: a productive, cold water pelagic ecosystem. Marine Ecology Progress Series, 216. 279-308. Publication - Article PeerReviewed 2001 ftnerc 2023-02-04T19:31:42Z The South Georgia region is characterised by high biomass and productivity of phytoplankton, zooplankton and vertebrate predators. Important commercial fisheries have been based at the island since the late 1700s, initially exploiting seals and whales, and currently taking krill Euphausia superba and finfish. Despite studies dating from the beginning of the last century, the causes of the high productivity remain unclear. The island lies within the Antarctic Zone of the Antarctic Circumpolar Current, to the south of the Polar Front. The offshore waters to its north and east are affected by a northwards deflection of the Southern Antarctic Circumpolar Current Front, together with waters from the Weddell-Scotia Confluence. Despite a retentive circulation over the shelf, the high productivity of phytoplankton and copepods is widespread, occurring far downstream and possibly extending to the Polar Front. High phytoplankton concentrations (>20 mg chlorophyll a m–3) may be linked to enhanced supply of iron or reduced forms of nitrogen (up to ~3 mmol ammonium m–3). Although macronutrients are generally not limiting in the Antarctic Zone, silicate concentrations of <1 mmol m–3 are growth-limiting at South Georgia in some summers. The growth season is long and blooms of >2 mg chl a m–3 occur for 4 to 5 mo. Biomass of krill plus net-caught zooplankton in summer is around 15 to 20 g dry mass m–2, equally dominated by krill and copepods. This greatly exceeds typical values for Antarctica, and is high compared to productive northern shelves. Zooplankton, and in particular krill, appear to have a pivotal role in regulating energy flow in this food web, through selective grazing and possibly also through nutrient regeneration. Abundances of krill and copepods are negatively related across a wide range of scales, suggesting direct interaction through competition or predation. Evidence suggests that when phytoplankton stocks are low, energy flow through krill is maintained by their feeding on the large populations of ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Euphausia superba Copepods Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Weddell |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
The South Georgia region is characterised by high biomass and productivity of phytoplankton, zooplankton and vertebrate predators. Important commercial fisheries have been based at the island since the late 1700s, initially exploiting seals and whales, and currently taking krill Euphausia superba and finfish. Despite studies dating from the beginning of the last century, the causes of the high productivity remain unclear. The island lies within the Antarctic Zone of the Antarctic Circumpolar Current, to the south of the Polar Front. The offshore waters to its north and east are affected by a northwards deflection of the Southern Antarctic Circumpolar Current Front, together with waters from the Weddell-Scotia Confluence. Despite a retentive circulation over the shelf, the high productivity of phytoplankton and copepods is widespread, occurring far downstream and possibly extending to the Polar Front. High phytoplankton concentrations (>20 mg chlorophyll a m–3) may be linked to enhanced supply of iron or reduced forms of nitrogen (up to ~3 mmol ammonium m–3). Although macronutrients are generally not limiting in the Antarctic Zone, silicate concentrations of <1 mmol m–3 are growth-limiting at South Georgia in some summers. The growth season is long and blooms of >2 mg chl a m–3 occur for 4 to 5 mo. Biomass of krill plus net-caught zooplankton in summer is around 15 to 20 g dry mass m–2, equally dominated by krill and copepods. This greatly exceeds typical values for Antarctica, and is high compared to productive northern shelves. Zooplankton, and in particular krill, appear to have a pivotal role in regulating energy flow in this food web, through selective grazing and possibly also through nutrient regeneration. Abundances of krill and copepods are negatively related across a wide range of scales, suggesting direct interaction through competition or predation. Evidence suggests that when phytoplankton stocks are low, energy flow through krill is maintained by their feeding on the large populations of ... |
format |
Article in Journal/Newspaper |
author |
Atkinson, A. Whitehouse, M.J. Priddle, J. Cripps, G.C. Ward, P. Brandon, M.A. |
spellingShingle |
Atkinson, A. Whitehouse, M.J. Priddle, J. Cripps, G.C. Ward, P. Brandon, M.A. South Georgia, Antarctica: a productive, cold water pelagic ecosystem |
author_facet |
Atkinson, A. Whitehouse, M.J. Priddle, J. Cripps, G.C. Ward, P. Brandon, M.A. |
author_sort |
Atkinson, A. |
title |
South Georgia, Antarctica: a productive, cold water pelagic ecosystem |
title_short |
South Georgia, Antarctica: a productive, cold water pelagic ecosystem |
title_full |
South Georgia, Antarctica: a productive, cold water pelagic ecosystem |
title_fullStr |
South Georgia, Antarctica: a productive, cold water pelagic ecosystem |
title_full_unstemmed |
South Georgia, Antarctica: a productive, cold water pelagic ecosystem |
title_sort |
south georgia, antarctica: a productive, cold water pelagic ecosystem |
publisher |
Inter-Research |
publishDate |
2001 |
url |
http://nora.nerc.ac.uk/id/eprint/18364/ http://www.int-res.com/articles/meps/216/m216p279.pdf |
geographic |
Antarctic The Antarctic Weddell |
geographic_facet |
Antarctic The Antarctic Weddell |
genre |
Antarc* Antarctic Antarctica Euphausia superba Copepods |
genre_facet |
Antarc* Antarctic Antarctica Euphausia superba Copepods |
op_relation |
Atkinson, A.; Whitehouse, M.J.; Priddle, J.; Cripps, G.C.; Ward, P.; Brandon, M.A. 2001 South Georgia, Antarctica: a productive, cold water pelagic ecosystem. Marine Ecology Progress Series, 216. 279-308. |
_version_ |
1766216662265102336 |