2 AgCenter scientists study new material to help preserve marine life after oil spills

Bruce Schultz, Nyman, John A., Green, Christopher  |  4/22/2015 12:18:44 AM

Chris Green, an LSU AgCenter fish physiologist, studies the effects of a dispersant on baitfish. Photo by Paula Ouder/Louisiana Sea Grant

A net holds small baitfish that are the subject of study to determine the effects of a chemical dispersant to be used in oil spill cleanups. Photo by Paula Ouder/Louisiana Sea Grant

News Release Distributed 04/21/15

BATON ROUGE, La. – Two LSU AgCenter scientists have been using small baitfish to study a new material that could help with oil spill cleanup. Their work began as the result of research started after the BP oil spill in the Gulf of Mexico five years ago.

Andy Nyman, LSU AgCenter coastal ecologist, and Chris Green, an LSU AgCenter fish physiologist, are testing a chemical produced by bacteria that could be used to help clean up oil spills. They are studying its effects on a small baitfish known as killifish, cocahoe minnow or larsh.

“These small things give us a chance to figure out what happened,” Nyman said.

To disperse the oil, a chemical known as a surfactant was used in Corexit, the dispersant used for the BP spill. Soap is a surfactant. So is the material used to make sure herbicides remain on the waxy surfaces of some leaves that ordinarily repel liquid.

Iowa State University, using a grant from the U.S. Environmental Protection Agency, developed a method of inducing bacteria to produce a substance that can be used as a surfactant by feeding agriculture wastes to the microbes. Columbia University has been studying the product’s effectiveness.

The two universities approached the LSU AgCenter about testing the product to determine its potential toxicity to marine life.

The EPA is looking for an alternative to the surfactant Corexit, used for the BP spill, because of concerns that it can have adverse effects on fish and other sea creatures.

Green said the two universities have developed two methods of making bacteria produce surfactants. One is to insert a gene into the microbes that induces them to make the substance. The other technique involves feeding the bacteria large amounts of rice hulls and sugarcane bagasse, which prompts the bacteria to produce a surfactant.

“What I’m doing is testing the toxicity of this material on fish, using cocahoe minnows,” Green said.

The baitfish was chosen because it can tolerate a wide range of salinity, Green said. That’s important because testing also involved determining if the surfactant’s effectiveness and toxicity is affected by salinity levels, he said.

Green said studies had shown that these newly produced surfactants were less toxic than the major components in Corexit.

“We found in our lab that the toxicity is greatly affected by the salinity,” Green said, adding that in some situations the bacteria surfactant is slightly less toxic than the surfactant material in Corexit.

Green said a Massachusetts company is interested in producing surfactants from bacteria that have potential as a cleaning agent. “There’s a huge need for this as an industrial compound.”

Green also conducted a study to determine the effects of crude oil on cocahoe minnows. Preliminary work shows that low doses of oil resulted in smaller amounts of egg yolk and reduced sperm movement in the minnows, he said.

Nyman said studies have shown that the surfactant in Corexit, when combined with crude oil, is more toxic than either crude oil or Corexit.

“You put the two together and something happens,” Nyman said.

Nyman recently took a coastal ecology class to an area at the mouth of the Mississippi River that had been contaminated with oil. He said the marsh had eroded into beach by about 100 yards, but no oil could be seen.

This is the final year of the three-year project, Green said. The last phase involves an educational outreach component. Green and Nyman are conducting meetings across Louisiana to explain the basics of toxic chemicals and their environmental effects.

“We get a dialogue with the audience,” Green said. “The more questions we get from the public, the better able we are to discuss things.”

They will make a presentation on May 20, 6:30 p.m. to 8:30 p.m., at a meeting of the Acadiana Chapter of the Sierra Club at the First United Methodist Church, 703 Lee Ave., Lafayette, 70501.

Bruce Schultz

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