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Atlanta, GA | Posted: April 20, 2016
A. Maureen Rouhi (maureen.rouhi@cos.gatech.edu)
Director of Communications
College of Sciences
Summary Sentence:
In the aftermath of the Deepwater Horizon blowout, the findings of basic research will help better address future disasters.
Full Summary:
No summary paragraph submitted.
C-IMAGE Team at SeaOn April 20, 2010, an explosion on the Deepwater Horizon (DWH) oil rig released a torrent of oil at the seafloor of the Gulf of Mexico, discharging close to 5 million barrels of oil in 87 days. It was the largest accidental oil spill in U.S. history.
Six years hence, the visible signs of the DWH disaster are fading, and the public may be lulled into assuming that all is fixed and well. In fact, many questions remain, and scientists continue to work tirelessly to address them. They include the team of Joel E. Kostka, a professor of biology in Georgia Tech’s College of Sciences. The hope is to develop effective spill mitigation and remediation technologies by understanding the effects of oil spills on marine environments. Kostka’s work on microbial oil degradation seeks to harness natural processes and native microorganisms to address disastrous oil spills.
Kostka’s research is part of the Gulf of Mexico Research Initiative (GoMRI), a 10-year, $500 million independent research program to study the impacts of the DWH oil spill and gain fundamental understanding of the dynamics of such events. Within GoMRI, the Kostka lab is funded under the Center for Integrated Modeling and Analysis of Gulf Ecosystems (C-IMAGE), a research consortium of 19 U.S. and international partners, led by the University of South Florida. Their goal is to advance the understanding of the processes, mechanisms, and environmental consequences of marine oil blowouts.
“We incorporate laboratory experimentation, field-oriented assessments, and modeling to predict the long-term fate and degradation of oil on Gulf ecosystems, especially at the seafloor.” Kostka says. "An especially exciting component of C-IMAGE is that we are comparing the effects of the DWH spill, in the northern Gulf of Mexico, to those of the Ixtoc spill, which occurred in 1979 near Campeche Bay, in the southern Gulf of Mexico." The Ixtoc spill was nearly as large as the DWH spill.
To understand the dynamics and impact of oil spills, the Kostka lab studies the microorganisms that break down oil. “We hypothesize that, similar to the breakdown of natural organic matter, biodegradation mediated by microbes is the ultimate fate of most of the spilled oil that enters the marine environment.” Thus, the Kostka lab studies how fast is, and what controls, the microbial degradation of oil in order to direct the management and cleanup of contaminated ecosystems.
During the DWH discharge in 2010, emergency responders used oil plume models to predict where the oil would go. However, microbial degradation of the oil was not included in most of the models, Kostka observes, “even though we know that a lot of the oil will be eaten by microbes.”
The Kostka lab now has measured how fast the oil was degraded in the deep waters and sediments in the northern Gulf of Mexico. “If there was an oil spill today, we could better predict where oil would go,” Kostka says, “because the model could include our measurements of biodegradation speeds under different oceanographic conditions.”
Working with scientists at Florida State University, Kostka and his team have studied the fate of the DWH oil that landed on Florida beaches and the microbes that degraded the oil. “Since beaches are exposed on shore, we could more easily follow the fate of the deposited oil,” Kostka says. “For the first time, we used state-of-the-art metagenomic techniques to track the oil-eating microbes for a period of more than one year after the oil it was deposited at Pensacola Beach in June 2010.”
Metagenomes are made up of all the genes from all the organisms present in the environment. The genetic sequences in the metagenome reveal the functions of microbes in the sample.
“Specific microbial groups were clearly related to how fast and which oil compounds were degraded,” Kostka says. “If there was an oil spill today, we would be able to tell responders how fast the oil would likely be degraded by microbes.”
On the Florida beaches impacted by the DWH discharge, the Kostka lab has also identified microbial groups that could be used as sentinels, or bioindicators, to tell responders whether important ecosystem services – such as organic matter decomposition and nutrient regeneration – are affected by oil exposure on the beach. “Now that we have established a baseline for the microbes present in beaches by using metagenomics, we could also advise environmental managers as to when the ecosystems are restored to close to the original condition.”
One interesting question that the research has raised is whether the Gulf is really a unique environment for microbes that eat oil.
Scientists had believed that because of the abundance of natural oil seeps in the Gulf, microbes there have adapted to oil and are therefore able to degrade oil quickly, Kostka says. However, comparing the rates at which microbes in the Gulf eat oil with those in other oceans such as the Beaufort Sea in the Arctic Ocean indicates that microbes in different waters degrade oil at similar rates under similar environmental conditions, Kostka’s research has found.
“The finding suggests that oil-eating microbes are present nearly everywhere and are capable of responding to oil spills under the right conditions,” Kostka says. This new hypothesis is supported by recent results showing that the plants of the sea – single-celled marine phytoplankton – naturally produce oil-like chemical compounds, which are eaten by other microbes. Thus, chemicals present in crude oil are naturally produced and consumed all the time nearly everywhere in the world’s oceans.
“The microbial potential for oil cleanup or mitigation appears to be naturally present in the world’s oceans,” Kostka says. “We just need to better understand the controls of that potential to be able to enhance cleanup and predict the fate of spilled oil.”
