Phytoplankton pigments have been used extensively to monitor standing stocks and rates of production and loss within algal communities. Chlorophyll-derived pigments that are formed during zooplankton grazing have also been used as tracers for the fate of phytoplankton. Recent advances in chromatography technology have revealed that phytoplankton pigments actually comprise a suite of related pigments and that some of these compounds appear to be uniquely associated with grazing by protozoa. This project with its simple, well-controlled experiments will evaluate pigment transformation and degradation by marine protozoa. It's been hypothesized that kinds and amount of pigments produced are related to grazer species and phytoplankton species, and that post- elimination processes such as detrital ingestion and photo- oxidation are important modifiers of pigments. A critical issue in the use of pigments as biomarkers is the degree to which pigment transformations mirror transformation of organic carbon. The ultimate goal of the project will be to develop a tracer which can be used to address several important ecological questions of upper food web dynamics.
