Oyster contaminated with oil spill. (Photo Credit: NOAA)
Effects of BP oil spill studied on oysters
Tuesday, June 25, 2013, 05:40 (GMT + 9)
Scientists are still researching the effects of the 2010 Deepwater Horizon oil spill to determine its impact on fauna and flora throughout the Gulf of Mexico.
Jerome La Peyre, who specializes in oyster diseases in the Louisiana State University (LSU) AgCenter School of Animal Sciences, is examining the effect of the oil by looking at biomarkers used to gauge oyster health.
His three-year research project is part of a multi-national consortium studying the impact of the BP oil spill and is being funded by BP for USD 183,000, with the money being administered independently through the Gulf of Mexico Research Initiative.
La Peyre noted that a host of variables are complicating the evaluation of the impacts of oil on oysters in estuaries.
“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.”
One of the two components of his research examines the effects of the oil and evaluates biomarkers in caged oysters kept at both oiled and non-oiled sites. This includes analysing oyster performance down to cells, proteins and genes.
The second component exposes oysters to oil-contaminated sediment in a laboratory and measures how the oysters react. La Peyre uses different combinations of water salinities and oil concentrations in order to assess the effects of oil independently from the effects of salinity but also their combined effects.
La Peyre has found a 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.
There had been oil and gas activity in the Barataria Bay basin, and some data was available prior to the Deepwater Horizon accident examining the presence of hydrocarbons in oysters, La Peyre said. Six months after the accident, the levels had recovered.
“Oil was found but only at background level,” he said.
La Peyre pointed out that the level of oyster reproduction and survival has been low since the oil spill, but because there have been other events typically associated with low reproduction and survival, it is difficult to discern how much of it was caused by the oil.
For example, in 2010, freshwater diversions along the Mississippi River were used at high levels to push oil away from the coastline -- and an influx of large amounts of freshwater can harm oysters by lowering the salinity levels they 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.
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