The role of microzooplankton in carbon cycling in the Southern Ocean
A 3-year study was carried out on the role of microzooplankton in carbon cycling in the south Atlantic and the Atlantic sector of the Southern Ocean. Microzooplankton grazing impact on phytoplankton was estimated during austral summer and winter employing the dilution technique. Carnivory by larger...
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1996
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ftrhodesunivcory:vital:21066 2023-05-15T13:57:15+02:00 The role of microzooplankton in carbon cycling in the Southern Ocean Froneman, Pierre William 1996 183 leaves pdf http://hdl.handle.net/10962/6234 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:21066 English eng Rhodes University Faculty of Science, Zoology and Entomology vital:21066 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:21066 http://hdl.handle.net/10962/6234 Froneman, Pierre William Thesis Doctoral PhD 1996 ftrhodesunivcory 2022-12-26T13:54:10Z A 3-year study was carried out on the role of microzooplankton in carbon cycling in the south Atlantic and the Atlantic sector of the Southern Ocean. Microzooplankton grazing impact on phytoplankton was estimated during austral summer and winter employing the dilution technique. Carnivory by larger zooplankton on microzooplankton during summer was estimated using in vitro incubations. Microzooplankton assemblages were always dominated by protozoans comprising ciliates and dinoflagellates. In the ( 20 um chlorophyll fraction, microzooplankton grazing was sufficient to control the growth of the nano- and picophytoplankton suggesting that, where larger microphytoplankton cells dominate, micro zooplankton maintain the background concentrations of the nano- and picophytoplankton. During winter, when small nano- and picophytoplankton cells dominate total chlorophyll concentrations, the microzooplankton grazing impact on phytoplankton is dramatically increased. Microzooplankton removed on average 37% of the initial phytoplankton stock or 70% of the daily phytoplankton production. These results suggest that in winter, micro zooplankton are the main sink for phytoplankton production. Carnivory experiments conducted with selected meso- (copepods) and macro zooplankton (euphausiids and tunicates) showed that all species examined consumed micro zooplankton in the presence of substantial chlorophyll concentrations. Microzooplankton can, therefore, be regarded as trophic intermediates between bacterioplankton, small phytoplankton cells and larger zooplankton species in the Southern Ocean. The results of this investigation suggest a spatiotemporal shift in efficiency of the biological pump mediated by changes in the size composition of the phytoplankton assemblages. South of the Antarctic Polar Front (APF) large IV microphytoplankton cells dominate the summer chlorophyll biomass, suggesting that larger zooplankton grazers represent the main sink for phytoplankton production. Under these conditions, carbon flux to the interior ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Southern Ocean Copepods Rhodes University Cory: Repository Antarctic Austral Southern Ocean The Antarctic |
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Rhodes University Cory: Repository |
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ftrhodesunivcory |
language |
English |
description |
A 3-year study was carried out on the role of microzooplankton in carbon cycling in the south Atlantic and the Atlantic sector of the Southern Ocean. Microzooplankton grazing impact on phytoplankton was estimated during austral summer and winter employing the dilution technique. Carnivory by larger zooplankton on microzooplankton during summer was estimated using in vitro incubations. Microzooplankton assemblages were always dominated by protozoans comprising ciliates and dinoflagellates. In the ( 20 um chlorophyll fraction, microzooplankton grazing was sufficient to control the growth of the nano- and picophytoplankton suggesting that, where larger microphytoplankton cells dominate, micro zooplankton maintain the background concentrations of the nano- and picophytoplankton. During winter, when small nano- and picophytoplankton cells dominate total chlorophyll concentrations, the microzooplankton grazing impact on phytoplankton is dramatically increased. Microzooplankton removed on average 37% of the initial phytoplankton stock or 70% of the daily phytoplankton production. These results suggest that in winter, micro zooplankton are the main sink for phytoplankton production. Carnivory experiments conducted with selected meso- (copepods) and macro zooplankton (euphausiids and tunicates) showed that all species examined consumed micro zooplankton in the presence of substantial chlorophyll concentrations. Microzooplankton can, therefore, be regarded as trophic intermediates between bacterioplankton, small phytoplankton cells and larger zooplankton species in the Southern Ocean. The results of this investigation suggest a spatiotemporal shift in efficiency of the biological pump mediated by changes in the size composition of the phytoplankton assemblages. South of the Antarctic Polar Front (APF) large IV microphytoplankton cells dominate the summer chlorophyll biomass, suggesting that larger zooplankton grazers represent the main sink for phytoplankton production. Under these conditions, carbon flux to the interior ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Froneman, Pierre William |
spellingShingle |
Froneman, Pierre William The role of microzooplankton in carbon cycling in the Southern Ocean |
author_facet |
Froneman, Pierre William |
author_sort |
Froneman, Pierre William |
title |
The role of microzooplankton in carbon cycling in the Southern Ocean |
title_short |
The role of microzooplankton in carbon cycling in the Southern Ocean |
title_full |
The role of microzooplankton in carbon cycling in the Southern Ocean |
title_fullStr |
The role of microzooplankton in carbon cycling in the Southern Ocean |
title_full_unstemmed |
The role of microzooplankton in carbon cycling in the Southern Ocean |
title_sort |
role of microzooplankton in carbon cycling in the southern ocean |
publisher |
Rhodes University |
publishDate |
1996 |
url |
http://hdl.handle.net/10962/6234 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:21066 |
geographic |
Antarctic Austral Southern Ocean The Antarctic |
geographic_facet |
Antarctic Austral Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean Copepods |
genre_facet |
Antarc* Antarctic Southern Ocean Copepods |
op_relation |
vital:21066 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:21066 http://hdl.handle.net/10962/6234 |
op_rights |
Froneman, Pierre William |
_version_ |
1766264846233370624 |