GeoChip 4.0 was used to compare microbial communities in oil-contaminated water to those from uncontaminated water in order to understand the effects of the 2010 Gulf of Mexico oil spill Lu et al., 2012a) . Results indicated that after only 40 days the presence of the hydrocarbon plume Frontiers in Microbiology | Microbiotechnology, Ecotoxicology and Bioremediation (1100 m depth) caused a significant shift in the microbial community functional structure and composition and that indigenous microorganisms, similar to known petroleum degraders, were stimulated by the hydrocarbon plume. Many genes associated with hydrocarbon degradation were significantly enriched in plume samples Lu et al., 2012a) . Genes that were enriched in plume samples included those for naphthalene 1,2-dioxygenase, β-oxidation of benzylsuccinate, cyclohexanone 1,2-monooxygenase, and alkene monooxygenase (Lu et al., 2012a) . These findings suggest that the microbial communities in the Gulf of Mexico were capable of intrinsic bioremediation and that the presence of the oil stimulated the oil-degrading community members and were important in determining the fate of the deep-sea oil spill.