Ecological consequences of environmental perturbations associated with offshore hydrocarbon production: a perspective on long-term exposures in the Gulf of Mexico

Abstract

A synthesis of the literature on benthic responses to marine pollution suggests that macroinfaunal and meiofaunal
communities exhibit repeatable patterns of response to sedimentary contamination generally detectable at high taxonomic
levels (even phylum). These responses appear to be jointly driven by intrinsic physiological and ecological characteristics of
higher taxa, such that crustaceans (especially amphipods and harpacticoids) and echinoderms are sensitive to toxics whereas
polychaetes, oligochaetes, and nematodes (especially non-selective deposit feeders) are enhanced by organic enrichment.
Application of this model to the GOOMEX results implies involvement of both toxicity and organic enrichment. Results of
toxicity tests and comparisons of observed contaminant concentrations to known effects levels imply that metals drive the
toxicity response. We conclude that (1) long-lasting effects of drilling activity exist in the sedimentary environment around gas
production platforms, (2) dual effects of toxicity and organic enrichment probably drive readily detectable responses in benthic
meiofauna and macroinfauna to 100–200 m, and (3) the failure to detect evidence of exposure or sublethal impacts on fishes
and most larger invertebrates is a joint consequence of their mobility over the relevant scales of environmental change and their
negligible exposure to hydrocarbons and other contaminants.