There have been reports of cloudy, muddy, or streaking water at several locations along the Magothy. A scientist from the Maryland Department of the Environment checked out a couple of sites and found significant blooms of the algae Prorocentrum minimum at each location. A sample off Dividing Creek measured 455,916 cells/ml, and one taken from Cockey Creek measured 110,615 cells/ml. MDE defines a “bloom” for this species at 3,000 cells/ml, so it is no surprise that something is up with the water!

This particular microorganism is the source of the “mahogany tides” that we regularly see in the Magothy River. There have been blooms of the same species reported in several other nearby rivers. Fortunately this phytoplankton does not produce toxins, and the life cycle of the organism is about two weeks so the water should clear up shortly although it may recur over the winter.

A picture of the bloom from the Dividing Creek area is shown below. It was taken at a magnification of 400x.