Oil-contamination effects on a hypersaline microbial mat community (Camargue, France) as studied with microsensors and geochemical analysis

Abstract

Pristine microbial mat samples from a hypersaline pond of a solar saltern (Camargue, France) were transferred into microcosms, contaminated in the laboratory with a viscous sulphur-rich crude oil, and characterized over time with microsensors for O₂, pH and H₂S, respectively. The goal was to gain information on how oil pollution affects the major autotrophic and heterotrophic processes involved in carbon cycling in coastal mats. Further, GC-MS analysis of mat samples taken directly after microsensor measurements was performed to investigate how the composition and the amount of oil changed over time in the oil contaminated mats. Pronounced biogeochemical changes in the microbial mat samples were observed during the experiment. The obtained results indicate that oil contamination stimulated organotrophic aerobic respiration and that C21-C28 alkanes of the crude oil were degraded/oxidized over time within the contaminated mats.