ESPINOZA, Johanna*; CATAPANE, Edward J.; CARROLL, Margaret A.; Medgar Evers College; Medgar Evers College; Medgar Evers College: Effects of Copper on O₂ Consumption in Gill of the American Oyster, Crassostrea virginica

The ongoing oyster rehabitation study our lab has been conducting showns that Crassostrea virginica transplanted to Jamaica Bay (JB), NY readily accumulate copper. Copper, a required trace metal in most cell systems, has prooxidant effects when present in excess. Mitochondria are sensitive to increased oxidative stress caused by metal toxicity. We studied effects of copper on 0₂ utilization in C. virginica. Respiratory rates were monitored using a YSI Micro Biological Oxygen Monitor. Using a continuous flow chamber we measured 0₂ consumption in whole gill tissues. Additions of copper to the respiratory chamber had an acute inhibitory effect. In other experiments, using batch chambers, we determined effects of copper on O₂ utilization in gill mitochondria from animals incubated 1-2 days with 0 to 100 PPB copper or grown for three years in JB. In control animals, adding 5 or 50 mg of CuSO₄ decreased respiratory rates by 12 and 32%, respectively. Oysters grown in JB or exposed to copper pretreatments were significantly more sensitive to acute copper additions to the respiratory chamber with 5 mg CuSO₄ additions decreasing O₂ utilization in excess of 34% and with 50 mg additions causing complete inhibition. The results indicate in vitro additions of copper have deleterious effects on mitochondrial O₂ utilization and exposure of oysters to copper in the lab or field heightens this deleterious effect. The toxic effects of copper on oyster gill mitochondrial respiration could be of physiological significance to the growth and long-term health of oysters and other marine animals living in a copper polluted environment. This work was supported by grants 1R25GM62003 of NIGMS, 0516041071 of NYSDOE and 66288-0035 of PSC-CUNY. We thank Frank M. Flower & Sons, Inc., Oyster Bay, NY for supplying oysters.