Wynn-Edwards_2014_Phytoplankton_Response.pdf (518.33 kB)
Species-specific variations in the nutritional quality of southern ocean phytoplankton in response to elevated pCO2
journal contribution
posted on 2023-05-18, 03:10 authored by Cathryn Wynn-EdwardsCathryn Wynn-Edwards, King, R, Davidson, A, Simon WrightSimon Wright, Peter Nichols, Wotherspoon, SJ, So KawaguchiSo Kawaguchi, Patti VirtuePatti VirtueIncreased seawater pCO2 has the potential to alter phytoplankton biochemistry, which in turn may negatively affect the nutritional quality of phytoplankton as food for grazers. Our aim was to identify how Antarctic phytoplankton, Pyramimonas gelidicola, Phaeocystis antarctica, and Gymnodinium sp., respond to increased pCO2. Cultures were maintained in a continuous culture setup to ensure stable CO2 concentrations. Cells were subjected to a range of pCO2 from ambient to 993 μatm. We measured phytoplankton response in terms of cell size, cellular carbohydrate content, and elemental, pigment and fatty acid composition and content. We observed few changes in phytoplankton biochemistry with increasing CO2 concentration which were species-specific and predominantly included differences in the fatty acid composition. The C:N ratio was unaffected by CO2 concentration in the three species, while carbohydrate content decreased in Pyramimonas gelidicola, but increased in Phaeocystis antarctica. We found a significant reduction in the content of nutritionally important polyunsaturated fatty acids in Pyramimonas gelidicola cultures under high CO2 treatment, while cellular levels of the polyunsaturated fatty acid 20:5ω3, EPA, in Gymnodinium sp. increased. These changes in fatty acid profile could affect the nutritional quality of phytoplankton as food for grazers, however, further research is needed to identify the mechanisms for the observed species-specific changes and to improve our ability to extrapolate laboratory-based experiments on individual species to natural communities. © 2014 by the authors.
History
Publication title
Water (Switzerland)Volume
6Issue
6Pagination
1840-1859ISSN
2073-4441Department/School
Institute for Marine and Antarctic StudiesPublisher
M D P I AGPlace of publication
SwitzerlandRights statement
Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/Repository Status
- Open