This especially affects seabirds. Their feathers are coated with sticky oil, which enables their insulation from the cold water and hampers their hunting. So many birds die of exposure or starvation. Some substances in oil are also toxic, e.g. they increase susceptibility to diseases in fishes and inhibit growth in phytoplankton. Amongst growth, oil also interferes with development, reproduction, and behaviour of most marine organisms.
Oil is broken down or decomposed by bacteria only very slowly.
All pictures by G. Schernewski.