Estimates of Phytoplankton carbon from high resolution optical sensors in the Southern Ocean

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dc.contributor.advisorVichi, Marcelloen_ZA
dc.contributor.advisorThomalla, Sandyen_ZA
dc.contributor.authorOgunkoya, Ayodele Gilberten_ZA
dc.date.accessioned2015-12-09T14:41:56Z
dc.date.available2015-12-09T14:41:56Z
dc.date.issued2015en_ZA
dc.description.abstractPhytoplankton is an important component of the oceanic carbon cycle, and deriving a good estimate of its carbon biomass (Cphyto) at ocean scale is difficult due to the lack of automatic sampling procedures. This is particularly difficult in the Southern Ocean, where winter conditions limit the sampling. This study explored the opportunity of using a high resolution data from the glider tracks in the Sub-Antarctic Zone of the Southern Ocean. The data consisted of particulate backscattering and chlorophyll and four different methods of estimating phytoplankton carbon were used, three of them based on backscattering (named 30%POC, B05 and M13) and one on chlorophyll (S09). The methods are different in their empirical formulations and source of original data. Three methods showed similar results despite the fact that one of them makes use of chlorophyll to derive Cphyto. Method M13 doubles that of the 3 other methods (~80mg C m-³ vs 40-50 mg C m-³). It was observed that discrepancy between M13 and the other 3 methods decreases with depth and when biomass was low (~0.25 mg Chl-a m-³) e.g., at depth 80 m. Investigating the drivers of variability in chl-a:C phyto ratios with depth and MLD shows little response and highlighted the need for more research in this region. Although M13 has a very low chl-a:Cphyto ratios, the range of variability was similar to that of the 30%POC and B05 methods and likely driven by variability in light and Fe limitation and changes in community structure. Despite a similar magnitude, the S09 method show a tight constrain in chl-a:Cphyto ratios that were methodologically driven and thus less sensitive to physiological adjustments in cellular chl-a:Cphyto ratios. The analysis also confirms that each oceanic region has factors that drive their variability and care needs to be taken when applying a method that was derived from one oceanic region to another.en_ZA
dc.identifier.apacitationOgunkoya, A. G. (2015). <i>Estimates of Phytoplankton carbon from high resolution optical sensors in the Southern Ocean</i>. (Thesis). University of Cape Town ,Faculty of Science ,Marine Research (MA-RE) Institute. Retrieved from http://hdl.handle.net/11427/15724en_ZA
dc.identifier.chicagocitationOgunkoya, Ayodele Gilbert. <i>"Estimates of Phytoplankton carbon from high resolution optical sensors in the Southern Ocean."</i> Thesis., University of Cape Town ,Faculty of Science ,Marine Research (MA-RE) Institute, 2015. http://hdl.handle.net/11427/15724en_ZA
dc.identifier.citationOgunkoya, A. 2015. Estimates of Phytoplankton carbon from high resolution optical sensors in the Southern Ocean. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Ogunkoya, Ayodele Gilbert AB - Phytoplankton is an important component of the oceanic carbon cycle, and deriving a good estimate of its carbon biomass (Cphyto) at ocean scale is difficult due to the lack of automatic sampling procedures. This is particularly difficult in the Southern Ocean, where winter conditions limit the sampling. This study explored the opportunity of using a high resolution data from the glider tracks in the Sub-Antarctic Zone of the Southern Ocean. The data consisted of particulate backscattering and chlorophyll and four different methods of estimating phytoplankton carbon were used, three of them based on backscattering (named 30%POC, B05 and M13) and one on chlorophyll (S09). The methods are different in their empirical formulations and source of original data. Three methods showed similar results despite the fact that one of them makes use of chlorophyll to derive Cphyto. Method M13 doubles that of the 3 other methods (~80mg C m-³ vs 40-50 mg C m-³). It was observed that discrepancy between M13 and the other 3 methods decreases with depth and when biomass was low (~0.25 mg Chl-a m-³) e.g., at depth 80 m. Investigating the drivers of variability in chl-a:C phyto ratios with depth and MLD shows little response and highlighted the need for more research in this region. Although M13 has a very low chl-a:Cphyto ratios, the range of variability was similar to that of the 30%POC and B05 methods and likely driven by variability in light and Fe limitation and changes in community structure. Despite a similar magnitude, the S09 method show a tight constrain in chl-a:Cphyto ratios that were methodologically driven and thus less sensitive to physiological adjustments in cellular chl-a:Cphyto ratios. The analysis also confirms that each oceanic region has factors that drive their variability and care needs to be taken when applying a method that was derived from one oceanic region to another. DA - 2015 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - Estimates of Phytoplankton carbon from high resolution optical sensors in the Southern Ocean TI - Estimates of Phytoplankton carbon from high resolution optical sensors in the Southern Ocean UR - http://hdl.handle.net/11427/15724 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/15724
dc.identifier.vancouvercitationOgunkoya AG. Estimates of Phytoplankton carbon from high resolution optical sensors in the Southern Ocean. [Thesis]. University of Cape Town ,Faculty of Science ,Marine Research (MA-RE) Institute, 2015 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/15724en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentMarine Research (MA-RE) Instituteen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherBiological Sciencesen_ZA
dc.subject.otherMarine Researchen_ZA
dc.titleEstimates of Phytoplankton carbon from high resolution optical sensors in the Southern Oceanen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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