Reddish-brown water from Prorocentrum minimum bloom

Long-term Studies of Phytoplankton Dynamics in the Rhode River, Maryland

Prorocentrum minimum bloom on the Rhode River 2001

Dating back to 1990, an ongoing time series of phytoplankton photosynthesis-irradiance parameters and ancillary data needed for the calculation of annual primary production has been measured in the Rhode River, Maryland, a shallow eutrophic sub- estuary of Chesapeake Bay.

Primary production has varied from 200 to 730 grams of carbon per meter squared per year. Photosynthesis-irradiance parameters varied nearly as much on interannual time scales as seasonally. Nevertheless, the presence or absence of major spring dinoflagellate blooms tended to be the factor that, to the greatest degree, governed the interannual variability of primary production. Substanial decadal scale variability in the frequency and magnitude of dinoflagellate blooms underscores the benefit of long-term observations in nutrient enriched coastal systems.