Monitoring Changes in Benthic Communities Adjacent to OCS Oil Production Platforms Off California

The effects of discharges from oil and gas production platforms off southern California are being monitored during a long-term (five-year) study. The monitoring program combines techniques of hypotheses testing with basic research on environmental processes. Parameters that are being measured at both soft bottom and hard bottom sites include currents, sediment characteristics, sediment resuspension and transport, chemistry (of sediments, pore water, animal tissues and drilling discharges), biological community structure, and the reproduction and life history of selected animals. The transport of platform discharged drilling fluids are being measured and modeled. In addition, experiments on trace metal partitioning and sediment resuspension under different sedimentological, redox and biological conditions are being conducted in the laboratory. The overall methodology, which has included extensive pre-impact sampling at control and regional stations, will attempt to provide a definitive evaluation of variability in the benthic environment as related to natural or anthropogenic causes.