Friday, August 20, 2010

GSU researchers to investigate oil-degrading microbes in the wake of Gulf oil spill

Georgia State University researchers will head to Louisiana this fall to see if clay minerals can be used to aid microbes to better break down oil in the wake of the Deepwater Horizon oil spill.

The research in the salt marshes is sponsored by a one-year, $61,537 Rapid Research Response (RAPID) grant from the National Science Foundation.

The research team includes Daniel Deocampo, W. Crawford Elliott, Larry Kiage, Eirik Krogstad and Seth Rose of the Department of Geosciences; Kuki Chin of the Department of Biology; and Gary Hastings of the Department of Physics and Astronomy.

"Anytime we can shave off the timeline for ecological restoration of the Gulf coast will have tangible economic and ecological impacts," said Daniel Deocampo, assistant professor of geosciences.

Georgia State researchers will select three experimental plots in the marshes. They will then spray the clay minerals, which occur there naturally, over the plots. Chunks of sediment and seawater will be taken back to the GSU lab in Atlanta for further analysis.

Deocampo said that the team will hopefully have preliminary data by spring 2011 - a quick turnaround for research.

The microbes that exist in the marshes have evolved over time to be able to ingest oil, as oil naturally seeps out of sediments in the Gulf of Mexico - albeit in significantly smaller amounts than the recent oil spill, said Kuki Chin, assistant professor of microbiology.

"So in this case, when the oil comes, it can be used as a food source," Chin said. "Some microbes can degrade sulfate as well as petroleum hydrocarbon."

There are thousands of species of microbes which can eat up oil, some existing on the surface of the water that are aerobic, meaning they rely on oxygen to live. Others existing in deeper sediment layers on the marshes are anaerobic and can live without oxygen.

What scientists don't know is the exact mechanism that encourages microbes to consume petroleum hydrocarbons, Deocampo said. In the lab, the application of clay minerals, particularly one called calcium montmorillonite, seems to encourage aerobic bacteria to consume more hydrocarbons.

"Clay minerals are really unique among minerals because they have a really high, natural electrical charge," he explained. "That charge has to be balanced somehow, and has to be balanced by magnesium or calcium in sea water."

But this can change, where particles called cations that carry the charge can go back and forth, depending on chemical reactions.

"The hypothesis is that when you have this charged surface with these cations on it, and put that right next to a cell wall of one of these microbes, the charged surfaces help the microbe to gain nutrients," Deocampo said.

Researchers will also test to see if the process functions in anaerobic bacteria in the same way as aerobic bacteria.

Chin said that environmental conditions could play a factor in how the microbes react in the Deepwater Horizon spill, causing a different reaction that the one which occurred during the Exxon Valdez spill in 1989.

"Environmental conditions, such as the temperature, can make a difference. We hope that in the marshes, the reactions could be quicker," she said.

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