The Role of Microorganisms in the Degradation of Marine Oil Spills - Term Paper Example

The role of microorganisms in the degradation of marine oil spills is being constantly investigated as the fate of petroleum compounds in the marine environment depends on their transformation or degradation by microbes. This time lag is effectively being reduced through processes such as bioremediation through which the available bacterial population is altered or increased by the addition of exogenous microbes and stimulation of indigenous population (Bioremediation methods for Oil Spills, n.d). Processes such as eutrophication have to lead to increased production of organic matter which in turn results in anaerobic conditions due to oxygen uptake by heterotrophic organisms.

Under such conditions mineralization of organic matter by processes such as sulfate reduction by marine-sulfate reducing bacteria can play a vital role. These anaerobic bacteria utilize sulfate as the final electron acceptor during their respiration which releases hydrogen sulfide into the environment. A number of enzymes are involved in this process and the large amounts of hydrogen sulfide released are vital from an ecological and economic viewpoint. Studies have also revealed a direct relationship between the number of sulfate-reducing bacteria and the amount of hydrogen sulfide released (Mudryk, Podgórska & Bolalek, 2000).

The identification of microbes which degrade crude oil has been done by serial dilution of seawater samples and plating them on mineral media followed by spraying a layer of crude oil on the agar plate. The bacterial isolates which appear after an incubation period are then screened by using overlay techniques (Sakalle & Rajkumar, 2009). In another techniques beach simulation tanks, oil-polluted cobble stones collected from a contaminated beach were put into tanks which were filled with seawater.

The gravel was then inoculated into enrichment cultures followed by broth and agar culture (Cerniglia & Perry, 2007). The DNA was then isolated from pure cultures and nucleotide sequencing of 16S rDNA was carried out which was then used for PCR amplification of the DNA. The PCR products were subjected to denaturing gradient gel electrophoresis by which the genus and species of bacteria were identified. (Sutiknowati, 2007).