February 9, 2006 Winter algal blooms are widely observed in the upper Chesapeake Bay and tributaries.

Since late December 2005, citizen and scientist reports of reddish to brownish colored water have been investigated by Maryland Department of the Environment and detected at water quality monitoring stations by Maryland Department of Natural Resources (DNR) primarily in the upper Chesapeake Bay and its tributaries. A non-toxic dinoflagellate algae, Heterocapsa rotundata, is among the Bay life that thrives in the cold water and lower light conditions of winter and early spring. Areas confirmed as having been, or are currently, heavily populated by the blooms of Heterocapsa have included Bodkin Creek on the Magothy River (26,880 cells/milliliter - last week of December 2005), the Hanover Street Bridge area of the Patapsco River (9,720 cells/milliliter - last week of December 2005), Swan Point in Kent County (124,917 cells/milliliter, 1/5/2006) and in the Corsica River from Cedar Point near the mouth of Emory Creek upstream to Sycamore Point and beyond (17,272 to 47,625 cells/milliliter, 1/31/2006). Ongoing bloom activity on the Corsica River can be tracked through DNR's Eyes on the Bay website and the Continuous Monitoring data with reference to chlorophyll levels, one indicator of the algal activity in the region.