Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean
Abstract Physico-chemical and biological studies during the austral summer of 1986–87 in the ice-edge and a region offshore of Antarctica indicated significant spatial differences in concentrations of nutrients, dissolved oxygen (DO), Ca, Mg, and chlorophyll a , and in the rates of primary productio...
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Cambridge University Press (CUP)
1992
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Online Access: | http://dx.doi.org/10.1017/s0032247400013425 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0032247400013425 |
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crcambridgeupr:10.1017/s0032247400013425 2024-03-03T08:38:24+00:00 Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean Shirodkar, P. V. Goes, J. I. Alagarsamy, R. Fondekar, S. P. 1992 http://dx.doi.org/10.1017/s0032247400013425 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0032247400013425 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Polar Record volume 28, issue 165, page 127-136 ISSN 0032-2474 1475-3057 General Earth and Planetary Sciences Ecology Geography, Planning and Development journal-article 1992 crcambridgeupr https://doi.org/10.1017/s0032247400013425 2024-02-08T08:32:23Z Abstract Physico-chemical and biological studies during the austral summer of 1986–87 in the ice-edge and a region offshore of Antarctica indicated significant spatial differences in concentrations of nutrients, dissolved oxygen (DO), Ca, Mg, and chlorophyll a , and in the rates of primary production. The waters within the ice-edge region were richer in nutrients and DO and showed a four-fold increase in chlorophyll a (1.98 mg m -3 ) and a 10-fold increase in primary productivity (0.74 mg C m -3 h -1 ) as compared with offshore waters. In the ice-edge region, Mg was high (1319 mg kg -1 ), whereas values of Ca (421.7 mg kg -1 ) were within the normal range. Offshore Ca (423.8 mg kg -1 ) and Mg (1297 mg kg -1 ) were within the expected limits. In the ice-edge region, Ca/Cl varied from 0.0202 to 0.0229, with a mean of 0.0220, and Mg/Cl varied from 0.0637 to 0.0737, with a mean of 0.0687. These figures were slightly higher than those offshore (Ca/Cl: 0.0205 to 0.0224, mean 0.0214; Mg/Cl: 0.0630 to 0.0693, mean 0.0657), indicating the addition of Mg to the waters in the ice-edge region. Nutrients in the ice-edge region showed increasing concentrations at deeper levels irrespective of their relationship with DO, indicating large amounts of preformed nutrients, a characteristic of Antarctic waters attributable to intense upwelling. Chlorophyll a showed a direct relation with primary productivity and an inverse relation with Mg, suggesting the release of Mg from biogenic matter. Offshore, phosphate-phosphorus (PO 4 -P) was significantly correlated with nitrate-nitrogen (NO 3 -N) and inversely correlated with primary productivity and chlorophyll a , indicating the utilization of PO 4 -P during high production. Significantly elevated concentrations of chlorophyll a, primary productivity and Mg, marked by a considerable decrease in nutrients, were observed at a frontal zone between 64° and 62°S. Article in Journal/Newspaper Antarc* Antarctic Antarctica Polar Record Southern Ocean Cambridge University Press Antarctic Southern Ocean Austral Indian Polar Record 28 165 127 136 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
General Earth and Planetary Sciences Ecology Geography, Planning and Development |
spellingShingle |
General Earth and Planetary Sciences Ecology Geography, Planning and Development Shirodkar, P. V. Goes, J. I. Alagarsamy, R. Fondekar, S. P. Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean |
topic_facet |
General Earth and Planetary Sciences Ecology Geography, Planning and Development |
description |
Abstract Physico-chemical and biological studies during the austral summer of 1986–87 in the ice-edge and a region offshore of Antarctica indicated significant spatial differences in concentrations of nutrients, dissolved oxygen (DO), Ca, Mg, and chlorophyll a , and in the rates of primary production. The waters within the ice-edge region were richer in nutrients and DO and showed a four-fold increase in chlorophyll a (1.98 mg m -3 ) and a 10-fold increase in primary productivity (0.74 mg C m -3 h -1 ) as compared with offshore waters. In the ice-edge region, Mg was high (1319 mg kg -1 ), whereas values of Ca (421.7 mg kg -1 ) were within the normal range. Offshore Ca (423.8 mg kg -1 ) and Mg (1297 mg kg -1 ) were within the expected limits. In the ice-edge region, Ca/Cl varied from 0.0202 to 0.0229, with a mean of 0.0220, and Mg/Cl varied from 0.0637 to 0.0737, with a mean of 0.0687. These figures were slightly higher than those offshore (Ca/Cl: 0.0205 to 0.0224, mean 0.0214; Mg/Cl: 0.0630 to 0.0693, mean 0.0657), indicating the addition of Mg to the waters in the ice-edge region. Nutrients in the ice-edge region showed increasing concentrations at deeper levels irrespective of their relationship with DO, indicating large amounts of preformed nutrients, a characteristic of Antarctic waters attributable to intense upwelling. Chlorophyll a showed a direct relation with primary productivity and an inverse relation with Mg, suggesting the release of Mg from biogenic matter. Offshore, phosphate-phosphorus (PO 4 -P) was significantly correlated with nitrate-nitrogen (NO 3 -N) and inversely correlated with primary productivity and chlorophyll a , indicating the utilization of PO 4 -P during high production. Significantly elevated concentrations of chlorophyll a, primary productivity and Mg, marked by a considerable decrease in nutrients, were observed at a frontal zone between 64° and 62°S. |
format |
Article in Journal/Newspaper |
author |
Shirodkar, P. V. Goes, J. I. Alagarsamy, R. Fondekar, S. P. |
author_facet |
Shirodkar, P. V. Goes, J. I. Alagarsamy, R. Fondekar, S. P. |
author_sort |
Shirodkar, P. V. |
title |
Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean |
title_short |
Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean |
title_full |
Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean |
title_fullStr |
Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean |
title_full_unstemmed |
Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean |
title_sort |
major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the indian ocean sector of the southern ocean |
publisher |
Cambridge University Press (CUP) |
publishDate |
1992 |
url |
http://dx.doi.org/10.1017/s0032247400013425 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0032247400013425 |
geographic |
Antarctic Southern Ocean Austral Indian |
geographic_facet |
Antarctic Southern Ocean Austral Indian |
genre |
Antarc* Antarctic Antarctica Polar Record Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Polar Record Southern Ocean |
op_source |
Polar Record volume 28, issue 165, page 127-136 ISSN 0032-2474 1475-3057 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0032247400013425 |
container_title |
Polar Record |
container_volume |
28 |
container_issue |
165 |
container_start_page |
127 |
op_container_end_page |
136 |
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1792506778629439488 |