Quotes of the Day

In the days after the April 20 explosion of the Deepwater Horizon oil rig, there was no way for the public to know how much oil could be leaking from the broken well 5,000 feet below the surface of the Gulf of Mexico. Weeks later, BP would release a tiny snippet of video of the surging leak, which the company estimated was discharging roughly 5,000 barrels, or 210,000 gallons, of oil a day. But independent scientists studying the video and measuring the growing slick at the surface suggested it could be five to 16 times that rate, or even greater if one took into account the enormous, hidden plumes of oil recently discovered under the sea — one such plume measured 10 miles long. Nonetheless, BP CEO Tony Hayward told Britain's Sky News on Tuesday morning that he didn't think the spill would seriously hurt the Gulf ecosystem. "Everything we can see at the moment suggests that the overall environmental impact will be very, very modest," he said.

Later the same day, however, BP finally released extended video of the underwater spill — and the picture got murkier. The images, posted on Florida Senator Bill Nelson's Web page, show thick funnels of oil still billowing into the water — this even after BP managed to hook up a hose that is siphoning off some of the leak.

At the same time, some scientists have intensified warnings that part of the oil slick could enter the Gulf's loop current, which curls around Florida, and put some sections of the coastline and the Florida Keys at risk. Federal officials have also raised alarms about the damage that has already been done to turtles, seabirds and marine mammals. And in response to concerns about the impact on undersea species, the National Oceanic and Atmospheric Administration (NOAA) on Tuesday expanded the no-fishing zone; nearly one-fifth of the Gulf, more than 47,000 square miles, is now off-limits for fishing. Far from having a "very, very modest" effect, the Gulf oil spill will linger for a very long time. "Make no mistake," said Rowan Gould, the acting director of the U.S. Fish and Wildlife Service. "This spill is sufficient to affect wildlife in the Gulf and across the region for years and perhaps decades."

Adding to the list of potential casualties of the oil is tourism to the Sunshine State, which depends heavily on vacationers' dollars. Already, a number of tar balls have washed up on the shores of Key West in Florida — though the Coast Guard is still working to find out whether that oil had come from the BP spill. (Some oil leaks naturally from the seafloor in the Gulf of Mexico.) And satellite maps of the oil spill show a long tail of oil being dragged east by a powerful eddy within the loop current, away from the site of the sunken Horizon rig — about 50 miles south of the Louisiana coastline — and toward the west coast of Florida.

The loop current carries water in a clockwise motion from southeastern Mexico to the northern Gulf, and then south to the Florida Keys before it winds around Florida and travels up the Atlantic coast. So far, federal officials say the oil has not been captured by the loop current, but some independent scientists believe it's only a matter of time. If a large amount of the oil were to fall into the current — and if the spill itself continued for months, which is possible — that would put much of Florida, southern coral reefs and parts of the Atlantic coastline at risk. "My worst nightmare is becoming a reality," said Senator Nelson on Tuesday at a hearing on the spill.

Jane Lubchenco, the head of NOAA, says that even if the crude did get swept up by the current, any oil that survived would likely be severely degraded. "The natural process of evaporation would reduce the oil volume and change its nature," she said in a teleconference Tuesday. "The remaining oil could be emulsified into long strips and mostly tar balls."

For now, the oil already appears to have impacted the sensitive species of the Gulf of Mexico. Federal officials said Tuesday that nearly 200 sea turtles, birds, dolphins and other animals have been found dead since the accident began. That's an unusually high number, though experts cautioned that until full necropsies have been carried out — a process that is still ongoing — it's impossible to confirm that the oil caused their deaths. But there's no doubt that the mutating oil slick poses a major threat to marine species in the area, especially to air-breathing animals like turtles, which need to break through the water surface to respire. "This spill is unprecedented," said Gould. "We may never know the full extent of the oil spill on birds and marine mammals."

That's doubly true for undersea species, which are far less likely to wash up on shore should they be killed. There is also ongoing debate over the use of chemical dispersants on the oil leak under the water — they seem to be breaking up the oil, but they also have unclear toxic effects on fish in the area. "In the use of dispersants we are faced with environmental trade-offs," acknowledged Environmental Protection Agency head Lisa Jackson at a Senate hearing Tuesday. She noted, "I'm amazed by how little science there is on [these chemicals]."

Jackson and Lubchenco appeared before members of Congress on a busy day of hearings, as did BP America head Lamar McKay, who has become the walking definition of beleaguered. Also taking part in the hearings was Interior Secretary Ken Salazar — in his first appearance before Congress since the spill — who unexpectedly admitted under questioning that lax regulation at his department may have contributed to the Horizon catastrophe. "We need to clean house," he told the Senate Energy and Natural Resources Committee. "We can make sure it never happens again."

• Bryan Walsh
• As the oil slick threatens to enter the loop current that curls around Florida and up the East Coast of the U.S., some scientists and federal officials predict increasing harm