News Release Distributed 05/27/13
BATON ROUGE, La. – While it has been three years since the Deepwater Horizon oil spill, scientists are still researching to determine its impact on the plants and animals that inhabit the ecosystems of the Gulf of Mexico.
Jerome La Peyre, a scientist who specializes in oyster diseases in the LSU AgCenter School of Animal Sciences, is studying the effect of oil by evaluating biomarkers that are used to assess oyster health.
His research, part of a multi-national consortium studying the impact of the oil spill, is being funded by research money set aside by BP and administered independently through the Gulf of Mexico Research Initiative. La Peyre’s three-year research project is receiving approximately $183,000 in funding.
A variety of confounding variables complicate the evaluation of impacts of oil on oysters in our estuaries, La Peyre said.
“Fluctuating temperatures, changes in water salinity and diseases can have an effect on oyster populations,” he said. “All of these make it difficult to unravel the effects of oil.”
La Peyre’s research has two components.
One examines the effects of the oil and evaluates biomarkers in caged oysters kept at oiled and non-oiled sites. These biomarkers include looking at the whole oyster performance down to its cells, proteins and genes.
The second component exposes oysters to oil-contaminated sediment under controlled laboratory conditions and measures the effect it has on the oysters.
For the lab component, La Peyre uses different combinations of water salinities and oil concentrations to be able to decipher the effects of oil independently from the effects of salinity as well as their combined effects.
One problem La Peyre encountered is the lack of significant previous research examining the biomarkers on oysters in subtropical estuaries found along the Gulf Coast.
“In many ways we are creating a database for the Gulf region that will be useful in future events such as another major oil spill,” La Peyre said.
Because of oil and gas activity in the Barataria Bay basin, some data was available prior to the Deepwater Horizon incident examining the presence of hydrocarbons in oysters, La Peyre said. He noted that six months after the accident, the levels had returned to the levels seen before the accident.
“Oil was found but only at background level,” he said.
La Peyre said the level of oyster reproduction and survival has been low since the oil spill, but other events typically associated with this occurrence also have occurred, making it difficult to discern exactly how responsible the oil is for the low numbers.
In 2010, freshwater diversions along the Mississippi River were operated at high levels to keep oil from reaching the coastline. An influx of large amounts of freshwater can have a negative effect on oysters by lowering the salinity levels that oysters prefer for reproduction, La Peyre said.
“Interpreting our oyster field data is sometimes challenging, but this research needs to be conducted to give us a better understanding of how oysters respond to specific events,” La Peyre said.
Craig Gautreaux