(AP) -- Federal scientists say they have dated coral living near the site of the busted BP oil well in the Gulf of Mexico at 2,000 years old.
The U.S. Geological Survey said Wednesday it had determined the age of the black coral in the Gulf for the first time. Scientists had been studying the ancient slow-growing corals before BP's well blew out on April 20, 2010. The corals were found about 21 miles northeast of the BP well living 1,000 feet below the surface of the Gulf.
"They're extremely old and extremely slow-growing," said Nancy Prouty, a USGS scientist. "And there are big questions about their vulnerability and their ability for recovery."
Black corals feed on organic matter sinking to the sea floor and it could take decades, or even centuries, to recover from "a disturbance to these ecosystems," Prouty said.
She said scientists were looking at whether the ancient coral had been damaged by the BP oil spill, but the damage assessment had not been completed.
The location of the black coral is important because computer models and research cruises have mapped much of the deepwater oil moving to the southwest of the BP well, away from the black coral colony. Scientists have found dead coral southwest of the well.
However, Prouty said the surface oil slick was over the black coral colony during the spill.
BP's well leaked more than 200 million gallons of oil after the Deepwater Horizon drilling rig exploded April 20, killing 11 workers.
Black corals, which resemble deep-sea bushes or trees, are found throughout the world and are an important marine habitat for fish and other forms of marine life. They grow very slowly - a human fingernail grows 200 times faster than black coral, USGS said.
Most of the Gulf's bottom is muddy and the coral colonies that pop up every once in a while are vital oases for marine life in the chilly ocean depths.
The USGS study was part of a larger federal survey of fragile reef ecosystems.
Explore further: Anxious monitoring near Florida coral reefs for oil spill