This oily haze could prove highly toxic to coral reefs. Both oil and dispersants, which chemically resemble dishwashing detergent, hamper the ability of corals to colonize and reproduce. And these effects are amplified when the two are mixed.

Image A deepwater coral reef in the Gulf of Mexico provides a home to many species. At least three such reefs lie beneath the oil slick. Credit... National Oceanic and Atmospheric Administration

Studies on the effects of oil and chemicals on coral are limited to the shallow-water variety, however. Essentially no research has been conducted on their slow-growing deepwater cousins. So BP’s spill has prompted scientists to embark on a sudden crash course on the interaction of deep-sea biology with these toxins.

“Everybody’s scrambling,” said Steve W. Ross, a marine biologist at the University of North Carolina, Wilmington, and an expert on deepwater corals. “There’s a lot of evaluation that has to be done.”

But some believe that studies on the impact of oil and dispersants should have been done long ago, given the proliferation of drilling rigs in the Gulf of Mexico.

“Some of these studies were proposed years ago, and the agencies decided not to fund them,” Dr. Ross said. “We’re paying the price for it now.”

The BP spill coincides nonetheless with a fertile period of deep-ocean exploration in the Gulf of Mexico. Over the past decade, the Minerals Management Service  the federal agency criticized by lawmakers for its oversight of the offshore drilling industry  has financed extensive research into mapping the life of the deep ocean.

On numerous voyages, researchers have scanned the sea floor for anomalies and deployed submersible robots to search for life in the icy depths. The result has been a string of discoveries across the northern gulf, among them prolific deepwater reefs the size of football fields or larger. The identification of new species has become commonplace.