Abstract

The impact of chronic exposure of Mareb Crude Oilon the rate of oxygen consumption of the clam, Tivela Ponderosa was studied in the laboratory. The bivalve Tivela ponderosa is exposed to (0.5, 1, and 1.5) ml/l of Mareb Crude Oil. The oxygen consumption of bivalves Tivelaponderosa was controlled hourly at 5th and 10th day (every two and six hours). After 5 and 10 days of exposure to crude oil concentrations, the average oxygen consumption in the clam after 5 days of exposure was (0.131, 0.135, 0.141, 0.319ml O2 gm-1 dry tissue h-1 every two hours) and (0.121, 0.124, 0.137, 0.247 ml O2 gm-1 dry tissue h-1 every six hours) and after 10 days it was (0.222, 0.561, 0.946, 1.117 ml O2 gm-1 dry tissue h-1 every two hours) and(0.126, 0.432, 0.573, 0.632 ml O2 gm-1 dry tissue h-1 every six hours). It was observed that the rate of oxygen consumption fluctuated with an increase in the exposure period. The increase in oxygen consumption in the treated clams can be explained by the high metabolic activity of the organisms due to the stress imposed by the pollutant. On the other hand, when increasing the exposure period for pollution substance decrease in oxygen consumption in the clams exposed to toxic substance concentrations. The possible reason for the latter is the insensitivity of the clams especially in high concentration of pollution substances.