Oil spill studies: A review of ecological effects

We reviewed seven particularly well known and/or studied oil spills that have occurred since the National Academy of Sciences 1975 report, Petroleum in the Marine Environment or that occurred prior to that report but about which significant new information has since been acquired. The spills studied were from the bargeFlorida, and tankersArrow, Argo Merchant, Amoco Cadiz, andTsesis and blowouts from the Bravo and Ixtoc I platforms.These best studies yield only limited insight into effects because they lack controls and have a high degree of natural variability. TheTsesis, Florida, andAmoco Cadiz cases are exceptional since they occurred in areas of ongoing research programs and had nearby areas suitable for controls. Oil spills have produced measurable effects on ecosystems that have not been readily predictable from laboratory studies on isolated organisms. However, ecosystemlevel interactions are poorly understood even without the complications resulting from effects of pollution. These generalizations emerge: oil regularly reaches sediments after a spill; oil in anoxic sediments is persistent; oil regularly contaminates Zooplankton and benthic invertebrates; fish are also contaminated, but to a lesser extent; oil contamination decreases the abundance and diversity of benthic communities.