The objectives of the study are: (a) to describe, for an active oil and gas producing field and an unaltered area, the existing ecosystems and the variability in their major components in time and space; and (b) to compare the concentrations of pollutants in the sediments, water and biota in an active field with those in an unaltered area and identify those changes associated with oil and gas exploration and production. Topic areas covered include: Sedimentology, geochemistry and trace metals; Distribution and abundance of macrobenthic and meiobenthic organisms; Demersal fishes and macro-crustaceans; Recreational fisheries and the distribution of predatory pelagic fishes; Ichthyoplankton; Effects of offshore oil field structures and their biotic environment--benthos and plankton; The effect of structures on migratory and local marine birds; Hydrography of the Buccaneer oil field and adjacent waters; Hydrocarbon levels and pathways in the major components of a marine ecosystem; Total organic carbon and carbon isotopes of sediments.