On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean
Thesis (PhD)--Stellenbosch University, 2020. ENGLISH ABSTRACT: Bioactive trace metals, including copper (Cu), zinc (Zn), nickel (Ni) and cadmium (Cd), are essential micronutrients to marine phytoplankton and their availability in the surface ocean has been shown to influence phytoplankton community...
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2020
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ftunstellenbosch:oai:scholar.sun.ac.za:10019.1/109418 2023-11-12T04:05:50+01:00 On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean Cloete, Ryan Roychoudhury, Alakendra N. Stellenbosch University. Faculty of Science. Dept. of Earth Sciences. 2020-10-19T14:34:03Z xx, 156 pages : illustrations (some color) application/pdf http://hdl.handle.net/10019.1/109418 en_ZA eng Stellenbosch : Stellenbosch University http://hdl.handle.net/10019.1/109418 Stellenbosch University Biogeochemistry -- Southern Ocean Trace metals -- Antarctic -- Southern Ocean Antarctica -- Southern Ocean -- Environmental conditions Phytoplankton -- Geographical distribution -- Maps Global environmental change Biogeochemical cycles -- Antarctic Ocean UCTD Thesis 2020 ftunstellenbosch 2023-10-22T07:36:54Z Thesis (PhD)--Stellenbosch University, 2020. ENGLISH ABSTRACT: Bioactive trace metals, including copper (Cu), zinc (Zn), nickel (Ni) and cadmium (Cd), are essential micronutrients to marine phytoplankton and their availability in the surface ocean has been shown to influence phytoplankton community composition and abundance. Through photosynthesis, phytoplankton are the primary drivers of the marine carbon cycle therefore constraining trace metal – phytoplankton dynamics, as well as other biogeochemical processes controlling trace metal distributions, is critical to understanding the greater carbon cycle. Owing to logistical constraints, less attention has been directed toward trace metal cycling on a seasonal basis. This is particularly important in the high latitude ocean regions where large seasonal fluctuations in environmental conditions e.g. light, wind and temperature, are likely to impact trace metal distributions directly or indirectly. To this end, this study focuses on the data scarce Southern Ocean and investigates the distribution and biogeochemical cycling of Cu, Zn, Ni and Cd in summer and in winter, two seasons with contrasting environmental conditions for phytoplankton growth. This framework provided a unique opportunity to characterise the Southern Ocean winter reset period and to assess the role of deep winter mixing as a potential in-situ physical trace metal supply mechanism to aid surface productivity. In order to address these questions, research cruises were conducted in summer and winter in the Atlantic sector of the Southern Ocean (0 - 8°E) while a third cruise took place in winter in the Indian Sector of the Southern Ocean (30°E). In the Atlantic sector, first winter measurements of dissolved (0.2 µm filtered seawater) Cu (dCu), Zn (dZn) and Ni (dNi) were compared with corresponding summer measurements from the same locations. Differences in trace metal distributions were most evident in the surface mixed layer where winter concentrations were consistently greater compared to summer. ... Thesis Antarc* Antarctic Antarctic Ocean Antarctica Southern Ocean Stellenbosch University: SUNScholar Research Repository Antarctic Southern Ocean Indian Antarctic Ocean |
institution |
Open Polar |
collection |
Stellenbosch University: SUNScholar Research Repository |
op_collection_id |
ftunstellenbosch |
language |
English |
topic |
Biogeochemistry -- Southern Ocean Trace metals -- Antarctic -- Southern Ocean Antarctica -- Southern Ocean -- Environmental conditions Phytoplankton -- Geographical distribution -- Maps Global environmental change Biogeochemical cycles -- Antarctic Ocean UCTD |
spellingShingle |
Biogeochemistry -- Southern Ocean Trace metals -- Antarctic -- Southern Ocean Antarctica -- Southern Ocean -- Environmental conditions Phytoplankton -- Geographical distribution -- Maps Global environmental change Biogeochemical cycles -- Antarctic Ocean UCTD Cloete, Ryan On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean |
topic_facet |
Biogeochemistry -- Southern Ocean Trace metals -- Antarctic -- Southern Ocean Antarctica -- Southern Ocean -- Environmental conditions Phytoplankton -- Geographical distribution -- Maps Global environmental change Biogeochemical cycles -- Antarctic Ocean UCTD |
description |
Thesis (PhD)--Stellenbosch University, 2020. ENGLISH ABSTRACT: Bioactive trace metals, including copper (Cu), zinc (Zn), nickel (Ni) and cadmium (Cd), are essential micronutrients to marine phytoplankton and their availability in the surface ocean has been shown to influence phytoplankton community composition and abundance. Through photosynthesis, phytoplankton are the primary drivers of the marine carbon cycle therefore constraining trace metal – phytoplankton dynamics, as well as other biogeochemical processes controlling trace metal distributions, is critical to understanding the greater carbon cycle. Owing to logistical constraints, less attention has been directed toward trace metal cycling on a seasonal basis. This is particularly important in the high latitude ocean regions where large seasonal fluctuations in environmental conditions e.g. light, wind and temperature, are likely to impact trace metal distributions directly or indirectly. To this end, this study focuses on the data scarce Southern Ocean and investigates the distribution and biogeochemical cycling of Cu, Zn, Ni and Cd in summer and in winter, two seasons with contrasting environmental conditions for phytoplankton growth. This framework provided a unique opportunity to characterise the Southern Ocean winter reset period and to assess the role of deep winter mixing as a potential in-situ physical trace metal supply mechanism to aid surface productivity. In order to address these questions, research cruises were conducted in summer and winter in the Atlantic sector of the Southern Ocean (0 - 8°E) while a third cruise took place in winter in the Indian Sector of the Southern Ocean (30°E). In the Atlantic sector, first winter measurements of dissolved (0.2 µm filtered seawater) Cu (dCu), Zn (dZn) and Ni (dNi) were compared with corresponding summer measurements from the same locations. Differences in trace metal distributions were most evident in the surface mixed layer where winter concentrations were consistently greater compared to summer. ... |
author2 |
Roychoudhury, Alakendra N. Stellenbosch University. Faculty of Science. Dept. of Earth Sciences. |
format |
Thesis |
author |
Cloete, Ryan |
author_facet |
Cloete, Ryan |
author_sort |
Cloete, Ryan |
title |
On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean |
title_short |
On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean |
title_full |
On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean |
title_fullStr |
On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean |
title_full_unstemmed |
On the distribution and biogeochemical cycling of bioactive trace metals in the Southern Ocean |
title_sort |
on the distribution and biogeochemical cycling of bioactive trace metals in the southern ocean |
publisher |
Stellenbosch : Stellenbosch University |
publishDate |
2020 |
url |
http://hdl.handle.net/10019.1/109418 |
geographic |
Antarctic Southern Ocean Indian Antarctic Ocean |
geographic_facet |
Antarctic Southern Ocean Indian Antarctic Ocean |
genre |
Antarc* Antarctic Antarctic Ocean Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Ocean Antarctica Southern Ocean |
op_relation |
http://hdl.handle.net/10019.1/109418 |
op_rights |
Stellenbosch University |
_version_ |
1782342111806357504 |