Coral 'impacted' by Gulf oil spill
Deep sea corals have been seriously harmed by the Deepwater Horizon oil spill, scientists have said.
A survey of one site near the well in the Gulf of Mexico uncovered "compelling evidence" of pollution damage.
Coral communities more than 4,000ft below the surface of the ocean appeared stressed and discoloured.
Tests showed that oil from the site bore Deepwater Horizon's chemical "fingerprint".
Determining the impact of oil spills at the bottom of the ocean can be difficult because oil seeps naturally from cracks in sea floor.
The explosion and blow-out in April 2010 poured an estimated 160 million gallons of oil into the Gulf, causing a major environmental disaster.
Scientists looked at 11 deep water coral sites three to four months after the well head was capped.
Healthy coral was found at all locations more than 20 kilometres from the Macondo oil prospecting site where the blow-out occurred.
But at one site 11 kilometres south-west of the well, coral colonies presented "widespread signs of stress" including bleaching and tissue loss. Almost half of the 43 corals observed at that site showed evidence of impact on more than half the colony.
The findings are published in the journal Proceedings of the National Academy of Sciences.