Hope for Re-establishing Microbial Populations in the Gulf of Mexico

2010 oil spill reduced diversity, but some species were unaffected.

Image courtesy of Green Fire Productions under a Creative Commons license.

The Science

To examine the impact of the Deepwater Horizon oil spill on microbial communities in the Gulf of Mexico, researchers have focused on the metatranscriptome—the expressed genetic information of the community as a whole. Metatranscriptomic analyses were used to compare microbial populations before and after the 2010 spill.

The Impact

Though the oil spill reduced microbial community diversity, some populations remain unchanged, suggesting that they may be important in the re-establishment of the original microbial community.

Summary

One of the first studies published in the aftermath of the Deepwater Horizon oil spill involved researchers from the Department of Energy (DOE) Joint Genome Institute (JGI), who confirmed that microbial communities played a role in dispersing hydrocarbons from the waters. A second 2012 study tracked populations of several microbial species in the Gulf of Mexico as they dominated the waters at various times to remove different fractions of the oil.

In this third study, researchers associated with DOE JGI used metatranscriptomics to examine species in the bathypelagic zone at depths of 1,000 to 4,000 m where no sunlight penetrates. Their analysis of roughly 66 million transcripts attributed 40% of the reads to just six genomes from Gammaproteobacteria known to be capable of breaking down methane and petroleum. The findings confirm that the diversity of microbes and their functional roles in the waters have decreased since the oil spill. However, the team also found that some microbial populations do not appear to be affected by the spill because their numbers are similar both before and after 2010. The researchers concluded that, “Despite the enormous bloom of hydrocarbon-degrading Gammaproteobacteria that increased bacterial cell counts by two orders of magnitude, members of the natural microbial community persisted at their pre-bloom activity levels and may be important in the re-establishment of the original microbial community.”

Contact

M. A. Moran
Department of Marine Sciences, University of Georgia, Athens 30602-3636
mmoran@uga.edu

Funding

This work was supported by the Gordon and Betty Moore Foundation, U.S. National Science Foundation grant OCE-1043225, and resources and technical expertise from the University of Georgia’s Georgia Advanced Computing Resource Center. The work conducted by the U.S. Department of Energy (DOE) Joint Genome Institute is supported by the Office of Biological and Environmental Research within DOE’s Office of Science under contract number DE-AC02-05CH11231.

Publications

Rivers, A. R., et al. “Transcriptional response of bathypelagic marine bacterioplankton to the Deepwater Horizon oil spill,” ISME J. 7, 2315–2329 (2013). [DOI: 10.1038/ismej.2013.129].