Trace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophores

Simple item page
dc.contributor.advisorPoulton, Alexen_ZA
dc.contributor.advisorLucas, Michael Ien_ZA
dc.contributor.advisorMoloney, Coleen Len_ZA
dc.contributor.authorHarington, Amyen_ZA
dc.date.accessioned2018-02-07T06:50:07Z
dc.date.available2018-02-07T06:50:07Z
dc.date.issued2017en_ZA
dc.description.abstractCoccolithophores are a biogeochemically important phytoplankton group, fulfilling an important role in the global carbon cycle through primary production and the formation and export of calcium carbonate. Despite this biogeochemical importance, relatively little is known about their ecophysiology, for example their response to nutrient availability in terms of both macronutrient (nitrate, phosphate) and micronutrient (trace metal) or how this impacts on their competition with other phytoplankton groups (e.g. diatoms, Synechococcus). Hence, this study investigated the response of coccolithophores to trace metal (iron, zinc and cobalt) additions in the high latitude North Atlantic (Iceland and Irminger basins) and the Southern Ocean (Great Calcite Belt, Scotia Sea). The response of coccolithophores to environmental conditions was investigated by examining distribution patterns in situ and in targeted bioassays where natural communities were incubated with elevated levels of trace metal concentration. The wide range of initial conditions for these bioassays (e.g. temperature, macro- and micro-nutrient availability and phytoplankton community composition), provided valuable insights into coccolithophore responses to trace metal addition across a range of different biogeographic regions. These responses were investigated in terms of coccolithophore cell abundances, species composition, calcite production and growth rates, and were contrasted with responses of the total phytoplankton community (chlorophyll α) and abundances of diatoms and other phytoplankton groups (e.g. Synechococcus). The major finding of this thesis is that iron addition positively enhances coccolithophore growth rates and calcite production in both the Northern and Southern subpolar oceans. Another significant finding was that zinc addition also positively enhanced growth rates of coccolithophores (and diatoms) in a number of bioassays across the Great Calcite Belt (Southern Ocean). Thus, the trace metals iron and zinc are important micronutrients to consider in regulating coccolithophore growth and calcite production. As climate change potentially altering the flux of such trace metals to the ocean it is therefore important to further investigate the role of these micronutrients in regulating coccolithophore communities and their biogeochemical impact.en_ZA
dc.identifier.apacitationHarington, A. (2017). <i>Trace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophores</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/27354en_ZA
dc.identifier.chicagocitationHarington, Amy. <i>"Trace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophores."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2017. http://hdl.handle.net/11427/27354en_ZA
dc.identifier.citationHarington, A. 2017. Trace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophores. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Harington, Amy AB - Coccolithophores are a biogeochemically important phytoplankton group, fulfilling an important role in the global carbon cycle through primary production and the formation and export of calcium carbonate. Despite this biogeochemical importance, relatively little is known about their ecophysiology, for example their response to nutrient availability in terms of both macronutrient (nitrate, phosphate) and micronutrient (trace metal) or how this impacts on their competition with other phytoplankton groups (e.g. diatoms, Synechococcus). Hence, this study investigated the response of coccolithophores to trace metal (iron, zinc and cobalt) additions in the high latitude North Atlantic (Iceland and Irminger basins) and the Southern Ocean (Great Calcite Belt, Scotia Sea). The response of coccolithophores to environmental conditions was investigated by examining distribution patterns in situ and in targeted bioassays where natural communities were incubated with elevated levels of trace metal concentration. The wide range of initial conditions for these bioassays (e.g. temperature, macro- and micro-nutrient availability and phytoplankton community composition), provided valuable insights into coccolithophore responses to trace metal addition across a range of different biogeographic regions. These responses were investigated in terms of coccolithophore cell abundances, species composition, calcite production and growth rates, and were contrasted with responses of the total phytoplankton community (chlorophyll α) and abundances of diatoms and other phytoplankton groups (e.g. Synechococcus). The major finding of this thesis is that iron addition positively enhances coccolithophore growth rates and calcite production in both the Northern and Southern subpolar oceans. Another significant finding was that zinc addition also positively enhanced growth rates of coccolithophores (and diatoms) in a number of bioassays across the Great Calcite Belt (Southern Ocean). Thus, the trace metals iron and zinc are important micronutrients to consider in regulating coccolithophore growth and calcite production. As climate change potentially altering the flux of such trace metals to the ocean it is therefore important to further investigate the role of these micronutrients in regulating coccolithophore communities and their biogeochemical impact. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - Trace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophores TI - Trace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophores UR - http://hdl.handle.net/11427/27354 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/27354
dc.identifier.vancouvercitationHarington A. Trace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophores. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/27354en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMarine Studiesen_ZA
dc.subject.otherMarine Biologyen_ZA
dc.titleTrace metal effects on phytoplankton in subpolar seas with special emphasis on coccolithophoresen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_sci_2017_harington_amy.pdf
Size:
11.16 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
PhD / Doctoral