Heidi M. Sosik
Coastal Phytoplankton dynamics revealed by automated submersible flow cytometry
Wednesday — September 11, 2013
Pacific Forum — 3:00 p.m.
Many aspects of how natural plankton communities are regulated remain poorly understood, in large part because traditional organism-level sampling strategies are not amenable to high frequency, long duration application. To overcome aspects of this limitation, we developed the FlowCytobot series of automated submersible flow cytometers capable of rapid, unattended analysis of individual phytoplankton cells for long periods of time. FlowCytobot and Imaging FlowCytobot use a combination of laser-based scattering and fluorescence measurements and video imaging of individual particles to enumerate and characterize cells ranging from picocyanobacteria to large chaining-forming diatoms. When combined with automated image processing and classification, these observations make it possible to characterize taxonomic composition of plankton communities with unprecedented temporal resolution, ranging from hours to years. In this talk I will highlight ways multi-year time series from deployments at coastal observatories are providing new insights into seasonal and interannual bloom dynamics on the New England shelf (Martha's Vineyard Coastal Observatory) and contributing both early warning and ecological context for Harmful Algal Bloom events in Texas waters. High resolution observations at the level of individual cells make it possible, not only to characterize community structure, but also to evaluate bottom up mechanisms through quantification of taxon-specific growth rates.