Untersuchungen über den einfluß von ölverschmutzungen auf meeresalgen. I. Die wirkung von rohölfilmen auf den CO2-gaswechsel außerhalb des wassers

Oil pollution in the sea is generally restricted to thin oil films floating on the water surface. Such oil films tend to coat littoral plants or animals during low tide. The effects of coating with crude oil on the CO₂-uptake of various marine algae has been investigated under conditions of emersion. In emersed algae, CO₂-uptake is more or less depressed, depending on the thickness of the oil film (0.1 to 0.0001 mm) and the type of crude oil (Iran, Libya, Venezuela). On the other hand, water loss during exposure is reduced, so that the oil-covered algae are able to photosynthesize over a longer period than algae without oil cover. After retransfer to oil-free sea water, in most cases photosynthesis rates remain depressed throughout the period of observation. There are two effects which probably interfere with gas exchange: (1) lowering of diffusion rates of photosynthetic gases and of water evaporation by the oil films; (2) toxic effects of crude-oil components.