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Phytoplankton community dynamics in nutrient-enriched mesocosms in the Baltic Sea: a chemotaxonomical approach
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Biology.
(English)Manuscript (Other (popular science, discussion, etc.))
URN: urn:nbn:se:uu:diva-92154OAI: oai:DiVA.org:uu-92154DiVA: diva2:165130
Available from: 2004-10-01 Created: 2004-10-01 Last updated: 2010-01-14Bibliographically approved
In thesis
1. Pigment and Thiamine Dynamics in Marine Phytoplankton and Copepods
Open this publication in new window or tab >>Pigment and Thiamine Dynamics in Marine Phytoplankton and Copepods
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Based on a field study and several mesocosm experiments, I evaluated the use of pigments as chemotaxonomical biomarkers for phytoplankton community composition in the Baltic Sea and I examined effects of inorganic nutrients on the dynamics of carotenoids and thiamine (vitamin B1) at the phytoplankton–copepod level in marine pelagic food webs.

My results show that HPLC pigment analysis combined with CHEMTAX data processing was an accurate alternative to microscopic analysis of Baltic Sea phytoplankton.

Experimental supply of N, P and Si affected copepod growth and biochemical status via changes in biomass and composition of their phytoplankton diet. Net population growth rates were generally higher when phytoflagellates dominated (low Si:N ratio) and lower when diatoms dominated (high Si:N ratio).

Copepod body concentrations of astaxanthin decreased with fertilization. Correlations with reduced under-water irradiance were consistent with the photo-protective function of this antioxidant. Thiamine concentrations in phytoplankton also decreased with fertilization. In copepods, low Si:N ratios resulted in higher thiamine concentrations than high Si:N ratios. Thiamine concentration and degree of phosphorylation were useful as indicators of thiamine shortage both in phytoplankton and copepods. The concentrations of thiamine and astaxanthin in the copepod communities were positively correlated.

As copepods constitute a major link between pelagic primary producers and higher trophic levels, fertilization effects may be responsible for astaxanthin and thiamine deficiencies in salmon suffering from the M74 syndrome, which appeared concurrently with large-scale eutrophication in the Baltic Sea. As both thiamine and astaxanthin are deficient in M74-affected salmon, there is a need for physiological and molecular investigations of possible interactions between the two compounds in living cells.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2004. 38 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 1016
Biology, phytoplankton composition, pigments, chemotaxonomy, inorganic nutrients, pelagic copepods, grazing, astaxanthin, thiamine, mesocosm experiments, marine food webs, eutrophication, Baltic Sea, Biologi
National Category
Biological Sciences
urn:nbn:se:uu:diva-4560 (URN)91-554-6042-9 (ISBN)
Public defence
2004-10-22, The lecture hall, Dept. of Plant Ecology, Villav. 14, Uppsala, 09:00 (English)
Available from: 2004-10-01 Created: 2004-10-01 Last updated: 2009-03-31Bibliographically approved

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