Bethany Fowler

• 
  One billion cells and counting: in situ observation and population modeling of a coastal phytoplankton community
  Bethany Fowler
  Picophytoplankton are the most abundant primary producers in the ocean. Knowledge of their community dynamics is key to understanding their role in marine food webs and global biogeochemical cycles. I will present on the analysis of an ongoing 16-year time series from the Martha’s Vineyard Coastal Observatory. We use a combination of autonomous flow cytometry and size-structured modeling to estimate taxon-specific vital rates for this picophytoplankton community. The results indicate that the picoeukaryotes reproduce and are lost much more rapidly than cyanobacteria at the same location. The picoeukaryotes appear to be a preferred prey item of the micrograzer community and so contribute more to the region’s primary productivity than would be inferred from their abundance alone. This work improves our understanding of the economically important Northeast US Shelf ecosystem and provides insight into the response of phytoplankton communities to environmental change across a range of timescales.