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Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands
Abstract Several questions pertaining to the marine communities at the Prince Edward Islands are addressed. Firstly, the nature of the 'island-mass effect', and the cause of the frequently recorded diatom blooms in the area are examined. It had been suggested that the cause of the blooms is related...
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2016
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| _version_ | 1867613208095752192 |
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| access_status_str | Open Access |
| author | Attwood, Colin Graham |
| author2 | Branch, George M |
| author_browse | Attwood, Colin Graham Branch, George M |
| author_facet | Branch, George M Attwood, Colin Graham |
| author_sort | Attwood, Colin Graham |
| collection | Thesis |
| description | Abstract Several questions pertaining to the marine communities at the Prince Edward Islands are addressed. Firstly, the nature of the 'island-mass effect', and the cause of the frequently recorded diatom blooms in the area are examined. It had been suggested that the cause of the blooms is related to the presence of a Taylor Column-induced, low density, stationary eddy which stabilises the water column. On a cruise in April/May 1989, temperature, salinity, nutrients, chlorophyll and primary production were measured at 90 stations in a large grid centred on the islands. These, together with data collected on previous cruises, are used to show that the repeated occurrence of diatom blooms was not a result of nutrient enhancement. No evidence for light-limitation of phytoplankton was found. The evidence and theoretical basis which was used to predict the existence of a Taylor Column is questioned. An alternative hypothesis for explaining the blooms is presented. It is argued that these local blooms are simply the result of seeding by a dormant stock of diatom resting spores from the shallow sediments around the islands. This hypothesis hinges on three observations: (1) the blooms occur only over shallow sediments and are not a feature of the open ocean, (2) the species Chaetoceros radicans has been responsible for the bloom each time the cells were identified, and (3) C. radicans forms a rapidly sinking, heavily silicified, resting spore. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/21843 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:29.432Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/21843 Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands Attwood, Colin Graham Branch, George M Lucas, Michael Zoology Marine Biology Abstract Several questions pertaining to the marine communities at the Prince Edward Islands are addressed. Firstly, the nature of the 'island-mass effect', and the cause of the frequently recorded diatom blooms in the area are examined. It had been suggested that the cause of the blooms is related to the presence of a Taylor Column-induced, low density, stationary eddy which stabilises the water column. On a cruise in April/May 1989, temperature, salinity, nutrients, chlorophyll and primary production were measured at 90 stations in a large grid centred on the islands. These, together with data collected on previous cruises, are used to show that the repeated occurrence of diatom blooms was not a result of nutrient enhancement. No evidence for light-limitation of phytoplankton was found. The evidence and theoretical basis which was used to predict the existence of a Taylor Column is questioned. An alternative hypothesis for explaining the blooms is presented. It is argued that these local blooms are simply the result of seeding by a dormant stock of diatom resting spores from the shallow sediments around the islands. This hypothesis hinges on three observations: (1) the blooms occur only over shallow sediments and are not a feature of the open ocean, (2) the species Chaetoceros radicans has been responsible for the bloom each time the cells were identified, and (3) C. radicans forms a rapidly sinking, heavily silicified, resting spore. 2016-09-20T12:34:47Z 2016-09-20T12:34:47Z 1991 Master Thesis Masters MSc http://hdl.handle.net/11427/21843 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Zoology Marine Biology Attwood, Colin Graham Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands |
| thesis_degree_str | Master's |
| title | Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands |
| title_full | Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands |
| title_fullStr | Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands |
| title_full_unstemmed | Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands |
| title_short | Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands |
| title_sort | investigations into the functioning of phytoplankton zooplankton kelp and benthic communities at the prince edward islands |
| topic | Zoology Marine Biology |
| url | http://hdl.handle.net/11427/21843 |
| work_keys_str_mv | AT attwoodcolingraham investigationsintothefunctioningofphytoplanktonzooplanktonkelpandbenthiccommunitiesattheprinceedwardislands |