Patuxent River Water and Habitat Conditions
from March to May, 2000

a map showing maximum daily air temperature and daily rain totals recorded by the National Weather Service at BWI Airport, March - May 2000

Air temperatures at Baltimore Washington International Airport in March and April fluctuated mostly between 50-80 degrees F with frequent rain events. According to the National Weather Service, this was the wettest April since 1983. The maximum daily air temperature then warmed steadily from 51 degrees F (April 27) to 92 degrees F (May 7 and 8) with very little rain.

a graph of mid Bay Surface Water Temperature compared with Prorocentrum density in the lower Patuxent River, March through May 2000.

  • CBOS data is used with permission of Dr. William Boicourt, University of Maryland Center for Environmental Science, Horn Point Laboratory in Cambridge, MD.
  • Prorocentrum minimum data is provided courtesy of Walt Butler, Maryland Department of Natural Resources, Annapolis, MD.

CBOS location mapWater temperatures in the Bay rose gradually in March and in April 2000 according to data collected by the University of Maryland Center for Environmental Science at the Chesapeake Bay Observing System (CBOS) buoy.

Algal samples are collected biweekly by the Maryland Department of Natural Resources field office during this time of year and showed a gradual increase in the density of Prorocentrum minimum from 106 cells/milliliter on March 7 to 3551 cells/milliliter on April 18.  The sunny, warmer weather in late April and early May generated a steep rise in the surface water temperature.  The temperature rise coincided with the significant bloom of Prorocentrum to 57,000 cells/milliliter in the lower Patuxent River on May 4.  Other bloom areas observed in early May were recorded by Richard Lacouture and the Academy of Natural Sciences and included the lower Potomac River and the mid Bay region south of the Bay Bridge (See distribution maps above, published courtesy of the Academy of Natural Sciences, St. Leonard, MD).

For more information, please contact Peter Tango at (410) 260-8651.

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