EFFECTS OF NATURAL PETROLEUM SEEPAGE ON THE DISTRIBUTION OF MACROFAUNAL ORGANISMS (POLYCHAETES) IN THE LA BREA AREA, TRINIDAD
Gobin, J.
Institute of Marine Affairs, Hilltop Lane, Chaguaramas,Trinidad-Tobago
La Brea is the site of the world famous "Asphalt or Pitch" Lake. The Lake represents a huge mass of heavy oil, sediments and sea water mixed by the churning action of gas ascending from the top of a dome of cretaceous shales (Kugler 1965). The La Brea region of Trinidad has one of the highest known oil seepage rates on earth; an estimated 100 barrels per day per 1000 square miles (Johnson 1971, Wilson et al 1974, Agard 1993). Only two other similar mega oil seepage areas have been studied in detail. These are Coal Point and Santa Barbara Channel in Southern California. As part of a larger ecological research project, macrofaunal and meiofaunal communities inhabiting this coastal area were investigated. Ten stations were sampled for macrofauna ( 3 replicates using a 0.4 m² van Veen grab) and meiofauna (3 replicates using 60 cm² cores). All macrofaunal taxa were identified and enumerated, the majority of which were polychaetes. Results will be presented and their implications in terms of a "hydrocarbon tolerant and adapted fauna" will be discussed.