Marine phytoplankton

Fresh and aged unispecific samples have been analyzed using IP-RPHPLC and PDA in order to reveal the chlorophylls and carotenoids alterations during senescence and death. Aging studies showed that cyanobacterial chlorophyll- a was destroyed faster than carotenoids in room oxic conditions. The reverse was found for the other eukaryotic species. Species with high chlorophyllase activity produced phytol free chlorophyll derivatives during death. The rate of chlorophyll-a destruction was; room oxic > room anoxic > cold anoxic. Pyropheophorbide-a was often the final product of type-I chlorophyll-a degradation. The conversion from fucoxanthin to fucoxanthinol was observed. Chlorophyll-c was found to be destroyed faster than chlorophyll-a. The quantitative relationship of certain "biomarker" pigments (e.g. fucoxanthin, zeaxanthin) to chlorophyll-a was found not to change significantly during the first 1--2 months senescence-death scenarios. This aids the field of chemotaxonomy in that valid estimations may still be made when phytoplankton populations contain senescent individuals.