Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean
The trophodynamics of the numerically dominant mesozooplankton (200-2000 m) in the vicinity of the Subtropical Convergence (STC) in the Indian sector of the Southern Ocean during austral autumn (April / May) 2007 were investigated as part of the Southern Ocean Ecosystem Variability Study. The survey...
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ftrhodesunivcory:vital:5791 2023-05-15T14:00:57+02:00 Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean Daly, Ryan 2009 77 p. pdf http://hdl.handle.net/10962/d1005479 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5791 English eng Rhodes University Faculty of Science, Zoology and Entomology vital:5791 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5791 http://hdl.handle.net/10962/d1005479 Daly, Ryan Zooplankton -- Antarctic Ocean Phytoplankton -- Antarctic Ocean Thesis Masters MSc 2009 ftrhodesunivcory 2022-12-26T12:00:25Z The trophodynamics of the numerically dominant mesozooplankton (200-2000 m) in the vicinity of the Subtropical Convergence (STC) in the Indian sector of the Southern Ocean during austral autumn (April / May) 2007 were investigated as part of the Southern Ocean Ecosystem Variability Study. The survey consisted of six north-south transects each bisecting the STC between 38º to 43ºS and 38º to 41º45’E. In total, 48 stations situated at 30 nautical mile intervals were occupied over a period of ten days. Hydrographic data revealed a well defined surface and sub-surface expression of the STC, which appeared to meander considerably between 41ºS and 41º15’S. Surface chlorophyll-a (chla) concentrations were low, ranging between 0.08 and 0.68 mg chl-a.m-3 and were generally dominated by the picophytoplankton (<2 m) which made up 66.6% (SD±17.6) of the total pigment. Chl-a concentrations integrated over the top 150m of the water column ranged between 11.97 and 40.07 mg chl-a.m-2 and showed no significant spatial patterns (p>0.05). Total integrated mesozooplankton abundance and biomass during the study ranged between 3934.9 and 308521.4 ind.m-2 (mean = 47198.19; SD±62411.4 ind.m-2) and between 239.8 and 4614.3 mg Dwt.m-2 (mean = 1338.58; SD ±1060.5), respectively. Again, there were no significant spatial patterns in the total mesozooplankton abundance or biomass within the region of study (p>0.05). No significant correlations were found between biological (chlorophyll-a concentrations and zooplankton abundance) and physico-chemical variables (temperature and salinity) (p>0.05). The total mesozooplankton community was numerically dominated by copepods of the genera Pleuromamma, Calanus, Oncaea and Oithona. Other important representatives of the mesozooplankton community included the tunicate, Salpa thompsoni, and the pteropod, Limacina retroversa. At the 40% similarity level, numerical analysis identified five distinct mesozooplankton groupings within the survey area. Differences between the groupings were ... Master Thesis Antarc* Antarctic Antarctic Ocean Southern Ocean Copepods Rhodes University Cory: Repository Antarctic Antarctic Ocean Austral Indian Southern Ocean |
institution |
Open Polar |
collection |
Rhodes University Cory: Repository |
op_collection_id |
ftrhodesunivcory |
language |
English |
topic |
Zooplankton -- Antarctic Ocean Phytoplankton -- Antarctic Ocean |
spellingShingle |
Zooplankton -- Antarctic Ocean Phytoplankton -- Antarctic Ocean Daly, Ryan Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean |
topic_facet |
Zooplankton -- Antarctic Ocean Phytoplankton -- Antarctic Ocean |
description |
The trophodynamics of the numerically dominant mesozooplankton (200-2000 m) in the vicinity of the Subtropical Convergence (STC) in the Indian sector of the Southern Ocean during austral autumn (April / May) 2007 were investigated as part of the Southern Ocean Ecosystem Variability Study. The survey consisted of six north-south transects each bisecting the STC between 38º to 43ºS and 38º to 41º45’E. In total, 48 stations situated at 30 nautical mile intervals were occupied over a period of ten days. Hydrographic data revealed a well defined surface and sub-surface expression of the STC, which appeared to meander considerably between 41ºS and 41º15’S. Surface chlorophyll-a (chla) concentrations were low, ranging between 0.08 and 0.68 mg chl-a.m-3 and were generally dominated by the picophytoplankton (<2 m) which made up 66.6% (SD±17.6) of the total pigment. Chl-a concentrations integrated over the top 150m of the water column ranged between 11.97 and 40.07 mg chl-a.m-2 and showed no significant spatial patterns (p>0.05). Total integrated mesozooplankton abundance and biomass during the study ranged between 3934.9 and 308521.4 ind.m-2 (mean = 47198.19; SD±62411.4 ind.m-2) and between 239.8 and 4614.3 mg Dwt.m-2 (mean = 1338.58; SD ±1060.5), respectively. Again, there were no significant spatial patterns in the total mesozooplankton abundance or biomass within the region of study (p>0.05). No significant correlations were found between biological (chlorophyll-a concentrations and zooplankton abundance) and physico-chemical variables (temperature and salinity) (p>0.05). The total mesozooplankton community was numerically dominated by copepods of the genera Pleuromamma, Calanus, Oncaea and Oithona. Other important representatives of the mesozooplankton community included the tunicate, Salpa thompsoni, and the pteropod, Limacina retroversa. At the 40% similarity level, numerical analysis identified five distinct mesozooplankton groupings within the survey area. Differences between the groupings were ... |
format |
Master Thesis |
author |
Daly, Ryan |
author_facet |
Daly, Ryan |
author_sort |
Daly, Ryan |
title |
Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean |
title_short |
Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean |
title_full |
Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean |
title_fullStr |
Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean |
title_full_unstemmed |
Trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the Indian sector of the Southern Ocean |
title_sort |
trophodynamics of mesozooplankton in the the vicinity of the subtropical convergence in the indian sector of the southern ocean |
publisher |
Rhodes University |
publishDate |
2009 |
url |
http://hdl.handle.net/10962/d1005479 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5791 |
geographic |
Antarctic Antarctic Ocean Austral Indian Southern Ocean |
geographic_facet |
Antarctic Antarctic Ocean Austral Indian Southern Ocean |
genre |
Antarc* Antarctic Antarctic Ocean Southern Ocean Copepods |
genre_facet |
Antarc* Antarctic Antarctic Ocean Southern Ocean Copepods |
op_relation |
vital:5791 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5791 http://hdl.handle.net/10962/d1005479 |
op_rights |
Daly, Ryan |
_version_ |
1766270344392343552 |