James River Balanced Healthy Phytoplankton Study

Interstate Commission on the Potomac River Basin

At the request of Virginia’s Department of Environmental Quality (VADEQ), ICPRB helped to further characterize balanced, healthy phytoplankton populations in Virginia tidal waters, and determine if the James River chlorophyll a criteria are protective of those populations.

ICPRB used a “reference-based” approach, which identifies and scores phytoplankton characteristics (metrics) that most strongly separate communities in high quality and degraded quality conditions. High quality conditions have adequate light for normal plant growth and concentrations of nitrogen and phosphorus low enough to limit algal bloom formation. These are the water quality conditions desired in a restored Chesapeake Bay on a broad level. ICPRB developed a Phytoplankton Taxonomic Index from the scored abundances of 77 individual taxa or taxonomic groups.

A final report was submitted to VADEQ in March 2015, revised in May 2015, and is available for here.