Amy Wold / The Advocate
NEW ORLEANS, La. -- Tuna and amberjack embryos developed abnormal hearts after being exposed to oil from the blown-out Deepwater Horizon well, even at weaker concentrations than what was found in the water after the 2010 BP disaster.
“The developing fish heart is very susceptible to chemicals found in crude oil,” said Nat Scholz, director of the ecotoxicology program with the NOAA Northwest Fisheries Science Center and co-author of the report.
The study, published in the Proceedings of the National Academy of Sciences, builds on more than 20 years of oil toxicity on fish that followed the 1989 Exxon Valdez oil spill.
Scientists exposed Atlantic bluefin tuna, yellowfin tuna and amberjack embryos to Deepwater Horizon oil collected from the surface and oil that was taken from the riser pipe under the water. When scientists monitored the heart development and function using digital microscopy, they found that the oil exposure led to a slowing of the heartbeat or an uncoordinated rhythm of a heart beat.
“The Deepwater Horizon oil disturbed the heart rate and rhythm of every species we tested,” said John Incardona, research toxicologist with NOAA’s Northwest Fisheries Science Center and lead author of the report.
The severity of the deformities and reduced function of the heart got worse as the concentrations of the oil increased, he said.
At high concentrations, the oil exposure can cause heart problems which leads to other deformities in the developing embryo. Those deformities would mean the fish would die soon after hatching. At low concentrations, the fish would survive after hatching, but the heart defects mean the long-term health of the fish would be compromised, Incardona said. The fish showed similar reactions to what was seen in the herring population in Alaska in the wake of the Exxon Valdez accident, he said.
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