The 2010 Deepwater Horizon blowout discharged roughly five million gallons of oil and up to 500,000 tons of natural gas into Gulf of Mexico offshore waters over a period of 84 days.
In the face of a seemingly insurmountable cleanup effort, many were relieved by reports following the disaster that naturally-occurring microbes had consumed much of the gas and oil.
Samantha Joye, a professor of marine sciences in the UGA Franklin College of Arts and Sciences, studies the oil plumes generated by the Deepwater Horizon blowout.
Credit: Todd Dickey, UGA
Now, a team of researchers led by University of Georgia marine scientists have published a paper in the journal Nature Geoscience that questions this conclusion and provides evidence that microbes may not be capable of removing contaminants as quickly and easily as once thought.
"Most of the gas injected into the Gulf was methane, a potent greenhouse gas that contributes to global climate change, so we were naturally concerned that this potent greenhouse gas could escape into the atmosphere," said Samantha Joye, senior author of the paper, director of the study and professor of marine science in UGA's Franklin College of Arts and Sciences. "Many assumed that methane-oxidizing microbes would simply consume the methane efficiently, but our data suggests that this isn't what happened."
Joye and colleagues from other universities and government organizations measured methane concentrations and the activity of methane-consuming bacteria for ten months, starting before the blowout with collection of an invaluable set of pre-discharge samples taken in March 2010.
The abundance of methane in the water allowed the bacteria that feed on the gas to flourish in the first two months immediately following the blowout, but their activity levels dropped abruptly despite the fact that methane was still being released from the wellhead.
This new data suggests the sudden drop in bacterial activity was not due to an absence of methane, but a host of environmental, physiological, and physical constraints that made it difficult or impossible for bacteria to consume methane effectively.
"For these bacteria to work efficiently, they need unlimited access to nutrients like inorganic nitrogen and trace metals, but they also need elevated methane levels to persist long enough to support high rates of consumption," Joye said. "The bacteria in the Gulf were probably able to consume about half of the methane released, but we hypothesize that an absence of essential nutrients and the dispersal of gas throughout the water column prevented complete consumption of the discharged methane."
Joye insists that while her group's conclusions differ from those presented in previous studies, there is no serious conflict between their analyses.
"The issue here was short-term sampling versus long-term time series sampling," she said. "I hope our paper clearly relays the message that long-term sampling is the only way to capture the evolution of a natural system as it responds to large perturbations like oil well blowouts or any other abrupt methane release."
Ultimately, scientists need to better understand the behavior of these microbes so that they may better gauge the environmental impacts of future accidents and methane releases due to climate change, she said.
"It's only a matter of time before we face another serious incident like Deepwater Horizon," Joye said. "The key is understanding the things that regulate how fast bacteria can consume methane, and that will give us insight into the ultimate fate of this potent greenhouse gas in our oceans."
Other authors on the paper include M. Crespo Medina, C.D. Meile, K.S. Hunter and J.J. Battles, University of Georgia; A-R. Diercks, V. L. Asper, A.M. Shiller and D-J. Joung, University of Southern Mississippi; V. J. Orphan and P. L. Tavormina, California Institute of Technology; L. M. Nigro, University of North Carolina, Chapel Hill; J.P. Chanton, Florida State University; R.M.W. Amon, Texas A&M University; A. Bracco and J.P. Montoya, Georgia Institute of Technology; T.A. Villareal, The University of Texas, Austin; A.M. Wood, NOAA Atlantic Oceanographic and Meteorological Laboratory.
Support for this study includes funding from the National Oceanic and Atmospheric Administration, the U.S. Department of Energy, the National Science Foundation and the Gulf of Mexico Research Initiative.
The full article is available online at http://dx.doi.org/10.1038/ngeo2156.
Samantha Joye | Eurek Alert!
Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
23.10.2017 | Event News
17.10.2017 | Event News
10.10.2017 | Event News
23.10.2017 | Life Sciences
23.10.2017 | Physics and Astronomy
23.10.2017 | Health and Medicine