Researchers study oil-spill effects on marsh birds

Richard Bogren, Stouffer, Philip C., Taylor, Sabrina S

News Release Distributed 05/16/13

BATON ROUGE, La. – LSU AgCenter researchers are studying a bird species that lives only in coastal marshes to try to determine how it may be affected the by the Deepwater Horizon oil spill in 2010.

Sabrina Taylor and Philip Stouffer in the LSU AgCenter School of Renewable Resources are collecting and analyzing feathers and tissue from seaside sparrows to see how they are surviving the presence of spilled oil.

They’re in the second year of a three-year study and are now collecting data. The challenge, the researchers said, is that the birds produce only one generation a year, and this year’s newborns are only emerging.

The evidence, however, suggests fewer birds in oiled areas. “They seem to be less successful in nesting in the contaminated marsh,” Stouffer said.

The researchers are looking at a gene that generates a protein involved in metabolizing polycyclic aromatic hydrocarbons, which are a toxic compound in crude oil, Taylor said.

Gene expression is a measure of active exposure to the toxin, she said. Greater expression indicates a greater level of exposure.

The gene Cytochrome P415 is involved in detoxification and appears across a whole range of organisms, from fish to mammals and birds, Stouffer said.

One factor that makes the seaside sparrow valuable in this study is that it lives only in the band of salt marshes along the Gulf Coast, Stouffer said. “They’re absolutely restricted to salt marsh, and they remain in Louisiana all their lives.”

The researchers tagged some birds last year so they could determine their movements during the breeding season. “It looks like they stay pretty close to where they started,” Stouffer said.

Because they aren’t aquatic birds and don’t swim or dive in water, seaside sparrows’ exposure to oil would have come from incidental contact on the shore or from eating oil or insects and other creatures that have oil in their systems, Taylor said.

Recent tropical storms and hurricanes apparently stirred up and moved oil, Stouffer said. “So rather than finding birds that were not exposed, we’re they’re looking at birds that were lightly exposed versus birds that were heavily subjected to oil.”

Stouffer and Taylor are part of a larger group of AgCenter researchers participating in a three-year, $12.2 million grant through the Louisiana Universities Marine Consortium (LUMCON) to evaluate the effects of the 2010 oil spill on coastal ecosystems in the Gulf of Mexico.

The AgCenter’s share of nearly $2 million is funding researchers looking at coastal insects and oysters as well as the seaside sparrow. The funds are from a 10-year, $500 million academic research fund established by BP as a result of the spill.

Rick Bogren

Photos by Phil Stouffer of field research can be found here.

5/16/2013 8:44:47 PM
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