Think of an oil spill, and images of fouled beaches and oil-soaked seabirds come to mind. But there are less visible effects as well. For instance, even low levels of oil pollution can damage the developing hearts of fish embryos and larvae, reducing the likelihood that those fish will survive. Scientists have known of this effect for some time, but the underlying mechanism has remained elusive.
Recently, researchers from NOAA Fisheries partnered with a team from Stanford University to discover how oil-derived chemicals disrupt the normal functioning of the heart muscle cells of fish. In an article in the February 14 issue of Science, they describe how polycyclic aromatic hydrocarbons, or PAHsa class of compounds prevalent in oilcan disrupt cardiac function in young bluefin and yellowfin tuna by blocking ion channels in their heart muscle cells.
The new findings are part of the Natural Resource Damage Assessment conducted by NOAA and other federal and state trustee agencies following the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. That spill occurred across a large region where the Western stock of Atlantic bluefin tuna spawn, raising the possibility that the eggs and larvae of this valuable species were exposed to crude oil. Natural Resource Damage Assessments are used to determine liabilities after a spill and to help develop restoration plans.
"We've known that oil causes problems with the hearts of developing fish based on research following the Exxon Valdez oil spill," said Nat Scholz, one of the authors of the paper and the leader of the Ecotoxicology Program at NOAA's Northwest Fisheries Science Center in Seattle. "Now that we better understand the precise mechanism, we can develop more subtle and sensitive indicators of cardiac stress in fish embryos and larvae and more accurately assess the impact of pollution on our natural resources," Scholz said.
Oil Compounds Block Ion Channels in Cardiac Muscle Cells
|Contact: Rich Press|
NOAA National Marine Fisheries Service