Phytoplankton growth: perspectives gained by flow cytometry

When applied to whole populations, phytoplankton growth represents composite patterns that may not apply to any individual cell in the population. We advocate an individual particle approach whereby knowledge of growth rates and biomass of individual cells is combined with knowledge of the relative abundance of like individuals (subpopulations) Here we review the conceptual background and report some results of an experimental program involving flow cytometry and mathematical modeling designed to test these concepts. We demonstrate that bulk rate measurements can vary without any change m individual growth rates. We explore inter- and intraspecific cell size relationships, and characterize variables that scale according to cell volume or area We report results of experiments involving novel, automated, single-cell approaches to the study of cell growth, metabolism and cell division