Measurement of Synechococcus in situ growth rates using flow cytometry and rRNA-targeted probes. Final report

摘要

The overall goal of this project was the development of methods for the estimation of in situ Synechococcus growth rates using flow cytometrically-measured cellular properties. As an important picoplanktonic primary producer, Synechococcus can be expected to significantly influence the cycling of carbon in coastal marine environments. Traditional methods for estimating growth rates in natural populations of these and other phytoplankton have relied upon bottle incubations, which take a long time to perform and are subject to a well known suite of artifactual bottle effects. The analytical approach the authors are developing would obviate the need for such incubations, thus avoiding bottle effects and allowing much higher sample through-put. Application of this approach to field populations of Synechococcus would contribute significantly to an understanding of the population dynamics of these organisms, and ultimately to an understanding of carbon cycling in coastal marine environments. The first step toward developing the proposed method for in situ growth rate determination is to establish the relationships between growth rate and cellular properties (e.g., cellular rRNA and DNA content) in Synechococcus strains growing under a variety of conditions. Establishing these relationships has been the focus of this project.