Does historical exposure to hydrocarbon contamination alter the response of benthic communities to diesel contamination?

• Published in: Marine environmental research Vol. 49; no. 3; pp. 255 - 278
• Main Authors: Carman, K.R., Fleeger, J.W., Pomarico, S.M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-04-2000; Elsevier
• Subjects: Algae; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Brackish; Copepoda; Crustacea - drug effects; Diesel; Drug Tolerance; Ecosystem; Ecotoxicology, biological effects of pollution; Eukaryota - drug effects; Foodwebs; Fresh water environment; Fundamental and applied biological sciences. Psychology; Gasoline - toxicity; Geologic Sediments - analysis; Louisiana; Marine; Marine Biology; Meiofauna; Microalgae; Microcosms; Mississippi; Nematoda; Nematoda - drug effects; Ostracoda; Polycyclic Aromatic Hydrocarbons - toxicity; Pseudostenhelia wellsi; Time Factors; Tolerance; USA, Louisiana; USA, Mississippi; Water Pollutants, Chemical - toxicity; Louisiana; Mississippi; United States; North America; America; ASW, USA, Louisiana; ASW, USA, Mississippi; Meiofauna; Tolerance; Microalgae; Diesel; Foodwebs; Microcosms; Freshwater environment; Pollutant; Food web; Sensitivity resistance; Hydrocarbon; Diesel fuel; Preexposure; Marsh; Zoobenthos; Water pollution; Invertebrata
• ISSN: 0141-1136; 1879-0291
• DOI: 10.1016/S0141-1136(99)00072-0

A microcosm experiment was used to compare the influence of diesel contamination on two benthic salt-marsh communities, one chronically exposed to petroleum hydrocarbons for decades (Louisiana [LA]) and the other relatively uncontaminated (Mississippi [MS]). Initial meiofaunal community composition of the two sites was similar. Higher organic content of MS sediments should have reduced bioavailability, and thus the toxicity of hydrocarbons relative to the LA site. Nevertheless, although responses to diesel contamination at the two sites were generally qualitatively similar, a species-specific and several community-response variables were influenced to a much greater degree in the MS community. In particular, the abundance of total nauplii, ostracods, and copepods were negatively impacted to a greater extent in MS than in LA, as was grazing by ostracods on benthic microalgae. Nematode:copepod ratios in contaminated sediments were much higher in MS than in LA sediments.
Pseudostenhelia wellsi (a benthic copepod) nauplii suffered greater adverse effects of diesel in MS than in LA. We conclude that the MS community was more sensitive to diesel contamination than was the LA community. The differential sensitivity is presumably a manifestation of different tolerances to hydrocarbon contaminants, mediated by a higher proportion of more tolerant species and/or increased tolerance among individual species in LA. Although the MS site was more sensitive to diesel contamination, qualitative responses of the LA and MS communities were similar, and comparable to previous studies of diesel contamination. The spatial and temporal consistency of diesel impacts on salt-marsh communities suggests that hydrocarbon contamination results in predictable community responses. Specifically, crustacean (e.g. copepods, ostracods, and nauplii) benthos are most sensitive to hydrocarbons. Reductions in abundance and grazing activity of crustaceans leads to enhanced algal biomass, reduced copepod diversity, and alters competitive interactions among meiofauna.