The Use of Experimental Ecosystems for Evaluating the Environmental Impact of Pollutants: A Comparison of an Oil Spill in the Baltic Sea and Two Long-Term, Low-Level Oil Addition Experiments in Mesocosms

Abstract

Scientific work with large experimental marine mesocosms has thus far received funding largely on the grounds that such research will help us to better evaluate the threat that various pollutants pose to the marine environment. Yet an authority in the field recently concluded that “large experimental ecosystems have probably taught us more about the general ecological interactions in such systems than about subtle long-term effects of pollutants” (Steele 1979). Does this mean that mesocosm research will not produce the kind of information needed by environmental protection agencies? One way to try to answer this question is to compare the effect of pollutants in experimental ecosystems with their effects in real ecosystems after intentional or accidental release. We present here such a comparison of two long-term, low-level oil-addition experiments in the mesocosms of the Marine Ecosystems Research Laboratory (MERL), University of Rhode Island, with the Tsesis oil spill study in the Baltic, and discuss how well the effects of an actual spill (Tsesis) could have been predicted on the basis of mesocosm experiments (MERL).