Hope for Reestablishing Microbial Populations in the Gulf of Mexico
Researchers used metatranscriptomic analyses to compare the microbial populations in the Gulf of Mexico before and after the Deepwater Horizon oil spill to learn more about the impact of petroleum being spilled into the waters. Though the oil spill reduced the diversity of the microbial communities in the Gulf of Mexico, some microbial populations remain unchanged suggesting that they may be important in reestablishing the original microbial community.
One of the first studies published in the aftermath of the Deepwater Horizon oil spill involved the Department of Energy’s Joint Genome Institute (DOE JGI) researchers and confirmed that microbial communities did play a role in dispersing the hydrocarbons from the waters. A second study released in 2012 tracked the populations of several microbial species in the Gulf of Mexico as they dominated in the waters at various time points to remove different fractions of the oil.
DOE JGI associated researchers recently carried out a new study of the microbial populations in the Gulf of Mexico, this time focusing on the expressed genetic information of an ecosystem, its metatranscriptomes. They examined species in the bathypelagic zone at depths of 1,000 to 4,000 meters underwater where no sunlight penetrates. The analysis of roughly 66 million transcripts sequenced for the study attributes 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 did not appear to be affected by the events that took place three years ago, as their numbers remain similar both before and after 2010.
“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 reestablishing the original microbial community,” the researchers concluded.
Rivers A.R., et al. 2013. “Transcriptional Response of Bathypelagic Marine Bacterioplankton to the Deepwater Horizon Oil Spill,” The ISME Journal 7, 2315-29. DOI:10.1038/ismej.2013.129.