Scientists are arguing against a widely publicized study which concluded that bacteria consumed the methane released from the Deepwater Horizon well in the Gulf of Mexico. This argument was sparked by a comment published in the May 27 issue of the journal Science.
Samantha Joye, marine scientists, lead author, University of Georgia Athletic Association Professor in Arts and Sciences and professor in the UGA Franklin College of Arts and Sciences, co-wrote the paper with researchers from 12 other institutions. They make the case that uncertainties in the hydrocarbon discharge from the blowout, oxygen depletion fuel by process other than methane consumption, a poor interpretation of genetic data and inadequacies of the model used by the authors of the previous study challenge the role of bacteria in the spill.
The previous study was published in the January 11 edition of Science. It was based on methane and oxygen distributions measured at 207 locations in the Gulf and concluded that “nearly all” of the methane released from the well was consumed within 120 days of the spill.
Joye explains that, “Our goal is to understand what happened to the methane released from the Macondo discharge and in the larger framework, to better understand the factors that regulate microbial methane consumption following large-scale gas releases.”
“I believe there is still a lot to learn about the environmental factors that regulate methane consumption in the Gulf’s waters and elsewhere,” she said. She explains that the January study neglected important factors that affect methane levels in the water.
Understanding what happened to the methane is important to the entire globe because methane is a potent greenhouse gas and global warming is predicted to accelerate the release of methane that is (temporarily) trapped in hydrates on the seafloor. The conclusions of the January study imply that the release of methane hydrates may not increase global warming and Joyce’s paper aims to fix that misconception; she and her colleagues note that many studies have found that methane released from natural deep-sea vents is not consumed by microbes.
“A range of data exists that shows a significant release of methane seeping out at the seafloor to the atmosphere, indicating that the microbial biofilter is not as effective,” Joye said. “Importantly for the future of the planet, there is even less evidence for a strong biofilter of methane hydrate destabilized in the shallow Arctic settings.”
Copyright © 2011 by Marine Science Today, a publication of OceanLines LLC