In the spring, summer, and winter of 1978-79, 673 samples were taken from around petroleum production platforms and control sites on the southwest Louisiana continental shelf to assess the effects of long-term petroleum exploration, drilling, and production activity on marine organisms. The 64,326 living Foraminifera recovered represent 51 species and 35 genera.
Standing crops are high (up to 3,294 living Foraminifera per 10 cm2), because of the large quantities of available food supplied by the Mississippi River, and because a wet picking method was used that preserved juvenile and delicate tests. Species diversity is generally low; two species, Nonionella basiloba and Buliminella bassendorfensis, account for nearly 76% of the total population. The species composition varies somewhat with season, water depth, and physical conditions.
The statistical analyses show little negative effects of petroleum operations on the benthic Foraminifera of this area. The foraminiferal populations are controlled by the physical parameters of this naturally stressed environment, especially by water depth, temperature and salinity fluctuations, sediment movement, and dissolved oxygen values. Proximity to platforms appears to cause no adverse effects on the organisms.