The effects of crude oil on marine microbial communities in sediments from the Persian Gulf and the Caspian Sea: A microcosm experiment

Changes in the microbial community in response to catastrophic oil spills in marine and fresh water environments have been well documented. Molecular methods provide tools for analyzing the entire bacterial community, covering also those bacteria that have not been cultured in the laboratory. In thisstudy, four different microcosms were set up containing sediments collected from the Persian Gulf and the Caspian Sea. One from each location was experimentally contaminated with crude oil and the other left for control. PCR-DGGE analyses were used for understanding the effect of crude oil on marinemicrobial community in the sediments. The results of this research show that after oil pollutionbiodiversity decrease in contaminated ecosystems in compare to uncontaminated ecosystems as H index was 3.56 in uncontaminated sediments but it was decrease to 2.7 after contamination. Also differentecosystems have resembled in microbial community after contamination. These results confirmed that crude oil induce major shifts in the composition and biodiversity of marine microbial community in the sediments.