THE SUBLETHAL EFFECTS OF NATURAL CHRONIC EXPOSURE TO PETROLEUM ON MARINE INVERTEBRATES

Abstract

ABSTRACT Comparative field studies were conducted in an area of natural chronic exposure to petroleum (Coal Oil Point) and at control sites between 1972 and 1974. Studies of the larger (mesh 2 mm) benthic infaunal invertebrates in shallow water (20-35 m) revealed organisms living in sediments with total CCl4 extractables higher than 10,000 mg/l at Coal Oil Point. These sediments contained petroleum hydrocarbons. The total CCl4 extractables in sediments from control sites which did not contain petroleum hydrocarbons were generally less than 100 mg/l. Petroleum hydrocarbons were recorded in tissues of abalone, mussels, and stalked barnacles from Coal Oil Point, although it is notable that all detected petroleum hydrocarbons were in the viscera and not in the foot of abalone. Data obtained in these studies did not reveal a significant change in reproduction, growth, or distribution that could be related to presence of petroleum in the tissues. However, there was a decrease in reproduction in stalked barnacles due to a “black body” effect of surrounding tar. There was no evidence of malformations in organisms living in the area of natural chronic exposure to petroleum. Petroleum hydrocarbons levels were higher in sediment and mussel tissues from Coal Oil Point than from the area around two producing oil rigs in the Santa Barbara Channel.