Abstract

Crude oil has become a part of the marine ecosystem through natural seeps and oil spills. Microbial communities have adopted various response mechanisms to adjust to oil spills that contaminate the marine environment and help restore the ecosystem to its original state. These response mechanisms ranges from change in indigenous microbial community composition, change in microbial diversity to gene diversity and modification. An instance for review was the deep-water horizon (DWH) oil spill in the Gulf of Mexico. The DWH oil spill was distinctive from other spills in terms of profundity, extent as well as its scale hence fears and enquiries about the state and outcome of the hydrocarbons at large is required. The main inquiry was about the metabolism ability of microbial communities; the ways, and to what degree the hydrocarbons can be metabolized. Various researches after the spill revealed that change in the successional patterns from the water column, shallow water and bottomless sea sediments to the coastline sediments saw the dominance of Roseobacter cluster within the Alphaproteobacteria on the surface, the Deltaproteobacteria closest to the wellhead, Cycloclasticus in shallow oil slicks, Colwellia and Alteromonas in the deep-sea hydrocarbon plume and sediment. These microbial communities help in bioremediation of oil during oil spills through their response mechanism. Factors such as nutrient limitation, hydrocarbon availability, ocean mixing and circulation among others also limit the rate at which microbial communities degrade hydrocarbons. This review outlines the response mechanism of microorganisms and how they help in hydrocarbon degradation.

Key words: Oil spills, microbial communities, microbial response, microbial degradation, hydrocarbons, deepwater horizon, Gulf of Mexico.