Hydrocarbon Biodegradation in Marine Sediments : A Biochemical Approach

Abstract

In an oil pollution sensitivity index ( 1 = low, 10 = high sensitivity) of coast types tidal flats have been ranked in position 9 (2). It is expected that the high-water shoreline will be heavily polluted after a near-coast tanker accident, while large tidal flats will be moderately, but ecologically critically, affected (1). Oil will penetrate into deeper sediment layers, thus enhancing toxicity against benthic organisms and favouring transition into anoxic zones, where biodegradation proceeds slowly, if at all (6). While mechanic oil removement is possible on sandy areas, it is mostly excluded at muddy flats which are frequent at the German coast. In these cases biodegradation is a main mechanism of restoration. To include biodegradation into an oil pollution management it is necessary to know biodegradation rates under the present conditions and support of biodegradation is desirable. This report deals with hydrocarbon biodegradation in tidal sediments and draws conclusions on practical measures of oil biodegradation support. Results have been obtained from in-situ experiments at tidal flats (4), from laboratory experiments using fresh sediments (5), as well as from laboratory experiments using a standardized and inoculated sediment mixture.