Published: Sunday, June 17, 2012, 9:31 AM
By Stan Freeman
NORTHAMPTON – Oil residue from the 2010 BP oil spill in the Gulf of Mexico could be causing potentially lethal defects in fish, according to a Smith College biologist.
“This oil is not gone yet. This disaster is not over. There are embryos right now that are still getting exposed to that oil,” said Michael J.F. Barresi, who, along with students at Smith College and the University of Massachusetts, conducted a study of the effects of oil residue of the type and in the concentrations that existed in the Gulf after the spill.
An article about the study and their findings appeared in a recent issue of BMC Biology, an online journal. Barresi was the lead investigator.
In April 2010, following an explosion aboard the Deepwater Horizon, an oil drilling rig, more than 200 million gallons of oil was released into the Gulf of Mexico. The largest oil spill in U.S. history, it contaminated nearly 650 miles of coastline.
Barresi and a team of students, including post-doctoral fellows, replicated conditions in the gulf in a controlled lab setting to test young fish for the effects of high concentrations of oil in the water.
They exposed zebrafish, a common freshwater fish often found in aquariums, to concentrations of oil in seawater that existed during the first year after the spill. Zebrafish are considered a good model for looking at the effect on embryonic development at the cellular and molecular level in fish.
Barresi said the researchers found that virtually all the fish embryos and larvae that were exposed were affected as they grew, most often dying or losing the critical reflexes that allowed them to escape predators, thus making them easy prey.
“I suspect that there will be an effect and that there has been an effect. In terms of the gravity of the effect, the only way that we will know is through long-term studies that will last over the next 20 years, of surveys (of aquatic populations),” he said. Barresi said his team’s study may be the first to assess specifically the impact of the oil contamination in the Gulf of Mexico on fish populations there.
Already, those studying general effects in the Gulf have observed an unusual spike in dolphin deaths, including stillborn dolphins in that region, he said. “Those stillborn dolphins are closest thing that we have (to embryos). I’d be very interested in knowing if any of those dolphins have any of those defects” that his study observed, Barresi said.
Special thanks to Richard Charter