Gulf of Mexico Offshore Operations Monitoring Experiment: Final Report. Phase 2: Sublethal responses to contaminant exposure

The Gulf of Mexico Offshore Operations Monitoring Experiment (GOOMEX): Phase I was designed to assess the nature and extent of chronic sublethal effects associated with the exposure of marine organisms to contaminants at three sites of long-term offshore oil and gas exploration and development. The findings of this experiment will be used to design further studies that will ultimately provide a scientific basis for developing monitoring techniques and strategies to assess environmental changes associated with the long-term presence of offshore oil and gas platforms. A chronic impact was defined as the cumulative effects of long duration contaminant exposure on the endemic benthos. Long duration sites were defined ass sites where platforms had been continuously present and actively producing for more than ten years. The most common contaminants discharged at platforms are hydrocarbons and trace metals. The underlying sediments were assumed to be the long-term repository for these contaminants. Contaminant surveys described the quantity and spatial and temporal variability of contaminants. Contaminant surveys described the quantity and spatial and temporal variability of contaminants in sediments, biota, and pore waters. Biological studies measured life history, reproductive success, reproductive effort and assemblage composition for a variety of organisms from meiofauna to megafauna. The induction of detoxification enzymes in megafauna were also evaluated (Table 1).