Date Awarded


Document Type


Degree Name

Master of Science (M.Sc.)


Virginia Institute of Marine Science


Morris Brehmer

Committee Member

Michael E. Bender

Committee Member

George Grant


Acute bioassays were conducted to determine the effects of thermal shock and chlorine exposure on the estuarine copepod Acartia tonsa. Laboratory conditions simulated power plant conditions using 8 C elevated temperatures and slug chlorination. A factorial design having temperatures at two levels and multiple chlorine additions, showed isolated effects of temperature and chlorine and their interaction. Adult Acartia tonsa withstood thermal shocks of 8 C above ambient summer temperatures of 20 to 25 C. No adverse effects were noted after 96 hours following an 8 ⃤ T over 5 seconds, holding at the elevated temperature for 5 minutes, and slowly returning to ambient within 20 minutes of exposure. Chlorine additions produced mass mortalities . At 20 C a chlorine residual of 0.75 ppm proved fatal to 30 percent of the organisms. Increasing the residual to 1.15ppm yielded 100 percent mortalities. At 25 C mortalities increased from 30 percent to 70 percent at the same 0.75 ppm residual levels. Temperature greatly governed copepods susceptibility to chlorination. Much of the equipment and techniques used in these experiments have not been previously described and are therefore explained in detail. This dissertation is from the Joint Program Degree from the College of William & Mary and University of Virginia and awarded by the University of Virginia.



© The Author