Oil giant BP has succeeded in connecting a mile-long pipe to capture the oil flowing into the Gulf of Mexico, a company spokesman said today.
"We are restarting the operation now'' to siphon oil to a above-water ship, said BP spokesman David Nicholas. He said the company had succeeded in connecting the tube late Saturday night, but ran into a glitch and had to stop the process, which it restarted Sunday.
The effort to connect two pieces of equipment a mile below the water's surface had also previously failed on Saturday.
It is unclear if the effort will totally cap the massive spill.
Word of huge submerged oil plumes, meanwhile, raised the specter of more damage to the ecologically rich Gulf. It also adds to questions about when large amounts of crude might hit shore. So far, tar balls have been sporadically washing up on beaches in several states, but oil hasn't come ashore in big quantities.
Researchers from the National Institute for Undersea Science and Technology said they had detected the underwater oil plumes at depths between just beneath the surface to more than 4,000 feet.
Three or four large plumes have been found, at least one that is 10 miles long and a mile wide, said Samantha Joye, a marine science professor at the University of Georgia.
The Environmental Protection Agency gave BP the go-ahead on Saturday to use dispersants, chemicals that break the oil into small droplets and keep it from rising to the surface.
"It appears that the application of the sub-sea dispersant is actually working,'' BP Chief Operating Officer Doug Suttles said. "The oil in the vicinity of the well is diminished from previous observations.''
But researchers Vernon Asper and Arne Dierks of the National Institute for Undersea Science and Technology at the University of Southern Mississippi said in Web posts that the large plumes were "perhaps due to the deep injection of dispersants.''
The researchers were also testing the effects of large amounts of subsea oil on oxygen levels in the water. The oil can deplete oxygen in the water, harming plankton and other tiny creatures that serve as food for a wide variety of sea creatures.
Oxygen levels in some areas have dropped 30 percent, and should continue to drop, Joye said.
At least 210,000 gallons of oil have been gushing into the Gulf each day since the Deepwater Horizon exploded on April 20, and some independent scientists think the leak may be 10 times that bad.
So far, winds and currents have kept the oil away from the Florida coast -- a trend that was likely to last through the weekend, according to the state Department of Environmental Protection.
Still, state officials continued preparations to safeguard the shoreline.
Technicians tried to stop the leak Saturday by guiding a six-inch-wide tube with a rubber stopper into the broken undersea pipe. But they had trouble connecting the tube to an oil tanker on the surface, and had to return the contraption to the surface.
"The challenge here is working with 5,000 feet of water,'' Suttles said.
BP hasn't given up on the tube strategy yet. Suttles said workers were trying it again Sunday morning. Officials are also tossing around another potential solution called a "junk shot.'' That entails shooting golf balls, shredded tires, knotted pieces of rope and other types of debris into the blowout preventer to clog the leak.
Environmentalists -- and some leaders in the fishing and oil-spill cleanup industries -- have raised concerns about using chemical dispersants.
"Cosmetically, it makes it seem that the oil has gone away,'' said Tom Manton, the retired president and CEO of the International Oil Spill Control Corporation. ``But the oil doesn't go away. It ends up in small drops, either on the beach or on the seabed...In many cases, the dispersants are more polluting to the water than the actual oil is.''
The EPA and Coast Guard, however, say that the dispersants are "generally less harmful'' than oil and will biodegrade in a shorter time span.
The Associated Press contributed to this report.