A new joint colloquium report from the American Academy of Microbiology (AAM), the American Geophysical Union (AGU), and the Gulf of Mexico Research Initiative (GoMRI) titled “Microbial Genomics of the Global Ocean System reports on science findings in the 10 years since the Deepwater Horizon (DWH) oil spill, which dumped 4.9 million barrels of oil and 250,000 metric tons of natural gas into the Gulf of Mexico over 86 days. The spill contaminated the open ocean, deep sea and more than 1,300 miles of Gulf shoreline.  A massive, interdisciplinary and collaborative research initiative was launched a decade ago to understand the effects of the oil spill – it supported the development and use of new genomic tools that have contributed greatly to our understanding of how to mitigate the effects of oil released into our oceans. 

Although hydrocarbon-degrading microbes seem exotic, they are found around the world in low abundance, even when crude oil is not present. In fact, GoMRI researchers discovered that many well-known types of microbes (ex: Bacteroidetes) have the potential to degrade hydrocarbons. During an oil spill, these low-abundance microbes sense hydrocarbons and move toward the source. There they flourish and reproduce. The bloom consumes hydrocarbons, sometimes transforming them into byproducts that are harder to break down. After depleting available nutrients, the bloom species die off and other organisms that degrade these byproducts dominate.

The microbial ecosystem in the Gulf of Mexico may have been primed for oil bioremediation before DWH because of persistent oil seepage in the waters from drilling. For example, genes for hydrocarbon degradation (ex: alkB) are found in uncontaminated samples from the Gulf of Mexico more commonly than in other regions around the world. After the DWH spill, hydrocarbon-degrading microbes dominated the microbial ecosystem in contaminated water, accounting for as much as 90% of the microbial community. 

Source: https://asm.org/Articles/2020/April/How-Microbes-Clean-up-Oil-Lessons-From-the-Deepwat