Deepwater Horizon Oil Spill Still Impacting Gulf Corals

The Deepwater Horizon oil spill of 2010 is still impacting corals in the Gulf of Mexico, proving that the effects of this calamity are deeper and broader than predicted, according to a new study.

"This study very clearly shows that multiple coral communities, up to 22 kilometers [14 miles] from the spill site and at depths over 1,800 meters [5,900 feet], were impacted by the spill," lead study author Charles Fisher, professor of biology at Penn State University, said in a statement.

Oil from the Deepwater spill - an accident that poured 4.9 million barrels of oil into the Gulf and killed 11 people, Nature World News reported - has largely dissipated, so scientists have to search for other clues as to how the oil is affecting marine life.

Fisher's team used the current conditions at a coral community known to have been impacted by the 2010 spill as a model "fingerprint" for gauging Deepwater's impact in newly discovered coral communities.

Corals, unlike other species, form a mineralized skeleton that can last for years after the organism has died, a marker in which researchers can find traces of the spill.

"One of the keys to coral's usefulness as an indicator species is that the coral skeleton retains evidence of the damage long after the oil that caused the damage is gone," Fisher explained.

Using 3D seismic data from the Bureau of Ocean Energy Management, the study team identified 488 potential coral habitats around the spill site, and then chose 29 sites they believed were most impacted by the spill. In addition, they the scientists used a remote-operated vehicle (ROV) to collect high-resolution images of corals at the sites.

The scientists compared the newly discovered coral communities with one they had discovered and studied around the time of the Deepwater catastrophe, and were able to identify damage caused by the oil spill.

"With the cameras on board the ROV we were able to collect beautiful, high-resolution images of the corals," said Fisher. "When we compared these images with our example of known oil damage, all the signs were present providing clear evidence in two of the newly discovered coral communities of the impact of the Deepwater Horizon oil spill."

Their findings were published in the journal Proceedings of the National Academy of Sciences.