Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean
Mesozooplankton community structure and grazing impact in the Polar Frontal Zone (PFZ) of the Southern Ocean were investigated during two cruises of the South African National Antarctic Programme (SANAP), the Marion Offshore Ecosystem Variability Study I & II (MOEVS). During the first cruise (MO...
Main Author: | |
---|---|
Format: | Master Thesis |
Language: | English |
Published: |
Rhodes University
2003
|
Subjects: | |
Online Access: | http://hdl.handle.net/10962/d1005417 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5731 |
id |
ftrhodesunivcory:vital:5731 |
---|---|
record_format |
openpolar |
spelling |
ftrhodesunivcory:vital:5731 2023-05-15T14:00:57+02:00 Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean Bernard, Kim Sarah 2003 103 p. pdf http://hdl.handle.net/10962/d1005417 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5731 English eng Rhodes University Faculty of Science, Zoology and Entomology vital:5731 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5731 http://hdl.handle.net/10962/d1005417 Bernard, Kim Sarah Zooplankton -- Antarctic Ocean Copepoda -- Feeding and feeds Thesis Masters MSc 2003 ftrhodesunivcory 2022-12-26T12:06:44Z Mesozooplankton community structure and grazing impact in the Polar Frontal Zone (PFZ) of the Southern Ocean were investigated during two cruises of the South African National Antarctic Programme (SANAP), the Marion Offshore Ecosystem Variability Study I & II (MOEVS). During the first cruise (MOEVS I), a meso-scale oceanographic grid survey was conducted in the upstream region of the Prince Edward Islands (PEI) in austral autumn (April) 2001. Mesozooplankton samples, collected using a Bongo net (fitted with 200 and 300µm mesh nets) at depths between 200 and 300 m, were separated into three size fractions: 200-500 µm; 500-1000 µm; 1000-2000 µm by reverse filtration. Total surface (depth <5 m) chlorophyll-a (chl-a) concentration (measured fluorometrically) during the study ranged between 0.11 and 0.34 µg 1^(-1) and was always dominated by picophytoplankton (<2.0 µm). Total mesozooplankton abundance and biomass during the survey ranged between 49 and 1512 ind. m^(-3) and between 0.7 and 25 mg Dwt. m^(-3), respectively. Throughout the survey, the 200-500 µm class numerically dominated the mesozooplankton community, comprising an average of ~ 69% (SD = ± 12.3%). The dominant species in the 200-500 µm size fraction were the copepods Oithona similis, Calanus simillimus and Metridia lucens and the pteropod, Limacina retroversa. However, in terms of biomass, the 1000-2000 µm group was predominant, with dry weight values constituting an average of ~ 66% (SD = ± 10.2%). Biomass was dominated by carnivorous zooplankton, particularly the euphausiids, Euphausia vallentini and Thysanoessa vicina and the chaetognaths, Sagitta gazellae and Eukrohnia hamata. Three distinct groupings of stations were identified by multivariate analysis. The different station groupings identified reflect changes in the relative contributions of the rather than different species assemblages. During the second cruise (MOEVS II), conducted in April 2002 (austral autumn), mesozooplankton community structure and grazing impact were ... Master Thesis Antarc* Antarctic Antarctic Ocean Mesozooplankton Prince Edward Islands South African National Antarctic Programme Southern Ocean Copepods Rhodes University Cory: Repository Antarctic Antarctic Ocean Austral Southern Ocean |
institution |
Open Polar |
collection |
Rhodes University Cory: Repository |
op_collection_id |
ftrhodesunivcory |
language |
English |
topic |
Zooplankton -- Antarctic Ocean Copepoda -- Feeding and feeds |
spellingShingle |
Zooplankton -- Antarctic Ocean Copepoda -- Feeding and feeds Bernard, Kim Sarah Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean |
topic_facet |
Zooplankton -- Antarctic Ocean Copepoda -- Feeding and feeds |
description |
Mesozooplankton community structure and grazing impact in the Polar Frontal Zone (PFZ) of the Southern Ocean were investigated during two cruises of the South African National Antarctic Programme (SANAP), the Marion Offshore Ecosystem Variability Study I & II (MOEVS). During the first cruise (MOEVS I), a meso-scale oceanographic grid survey was conducted in the upstream region of the Prince Edward Islands (PEI) in austral autumn (April) 2001. Mesozooplankton samples, collected using a Bongo net (fitted with 200 and 300µm mesh nets) at depths between 200 and 300 m, were separated into three size fractions: 200-500 µm; 500-1000 µm; 1000-2000 µm by reverse filtration. Total surface (depth <5 m) chlorophyll-a (chl-a) concentration (measured fluorometrically) during the study ranged between 0.11 and 0.34 µg 1^(-1) and was always dominated by picophytoplankton (<2.0 µm). Total mesozooplankton abundance and biomass during the survey ranged between 49 and 1512 ind. m^(-3) and between 0.7 and 25 mg Dwt. m^(-3), respectively. Throughout the survey, the 200-500 µm class numerically dominated the mesozooplankton community, comprising an average of ~ 69% (SD = ± 12.3%). The dominant species in the 200-500 µm size fraction were the copepods Oithona similis, Calanus simillimus and Metridia lucens and the pteropod, Limacina retroversa. However, in terms of biomass, the 1000-2000 µm group was predominant, with dry weight values constituting an average of ~ 66% (SD = ± 10.2%). Biomass was dominated by carnivorous zooplankton, particularly the euphausiids, Euphausia vallentini and Thysanoessa vicina and the chaetognaths, Sagitta gazellae and Eukrohnia hamata. Three distinct groupings of stations were identified by multivariate analysis. The different station groupings identified reflect changes in the relative contributions of the rather than different species assemblages. During the second cruise (MOEVS II), conducted in April 2002 (austral autumn), mesozooplankton community structure and grazing impact were ... |
format |
Master Thesis |
author |
Bernard, Kim Sarah |
author_facet |
Bernard, Kim Sarah |
author_sort |
Bernard, Kim Sarah |
title |
Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean |
title_short |
Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean |
title_full |
Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean |
title_fullStr |
Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean |
title_full_unstemmed |
Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean |
title_sort |
mesozooplankton community structure and grazing impact in the polar frontal zone of the southern ocean |
publisher |
Rhodes University |
publishDate |
2003 |
url |
http://hdl.handle.net/10962/d1005417 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5731 |
geographic |
Antarctic Antarctic Ocean Austral Southern Ocean |
geographic_facet |
Antarctic Antarctic Ocean Austral Southern Ocean |
genre |
Antarc* Antarctic Antarctic Ocean Mesozooplankton Prince Edward Islands South African National Antarctic Programme Southern Ocean Copepods |
genre_facet |
Antarc* Antarctic Antarctic Ocean Mesozooplankton Prince Edward Islands South African National Antarctic Programme Southern Ocean Copepods |
op_relation |
vital:5731 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5731 http://hdl.handle.net/10962/d1005417 |
op_rights |
Bernard, Kim Sarah |
_version_ |
1766270344720547840 |