MICROORGANISMS AND HYDROCARBONS IN THE NORTH SEA DURING JULY-AUGUST 1975

ABSTRACT The 1975-1976 North Sea Oil Ecology Investigation is designed to determine the dynamics of oil pollution in the North Sea and to serve as a baseline study at the start of the rather extensive oil exploitation of the seabed of the North Sea. In designing the experiment, particular attention has been paid to the 1974-1975 research effort of the Gulf Universities Research Consortium directed towards determining the effect, if any, of offshore oil exploitation in Louisiana on the area's ecology. As a result, both projects address the distribution of hydrocarbons and their possible concentration in the water, sediment, and living organisms, and the determination of the rates of degradation and effect of hydrocarbons on the food web. Preliminary analyses and study of cruise data taken in the North Sea during July-August 1975 indicates that there appears to be a tendency for higher numbers of microorganisms to be associated with the most active oil field, “Ekofisk;” there is also some indication of microbial response to outflow from the Elbe River. The uniform low levels of hydrocarbons in the sediment suggest that microorganisms are active as shown by ratios of higher hydrocarbon bacteria to heterotrophs in the “Ekofisk” area.