The spewing crude was eluding BP's latest containment effort, which captured a small amount of the gushing pollutants before equipment became dislodged Sunday.
Researchers have found more underwater plumes of oil than they can count from the blown-out well, said Samantha Joye, a professor of marine sciences at the University of Georgia. She said careful measurements taken of one plume showed it stretching for 10 miles, with a 3-mile width.
The hazardous effects of the plume are two-fold. Joye said the oil itself can prove toxic to fish swimming in the sea, while vast amounts of oxygen are also being sucked from the water by microbes that eat oil. Dispersants used to fight the oil are also food for the microbes, speeding up the oxygen depletion.
"So, first you have oily water that may be toxic to certain organisms and also the oxygen issue, so there are two problems here," said Joye, who is working with a group of scientists who discovered the underwater plumes in a recent boat expedition to the Gulf. "This can interrupt the food chain at the lowest level, and will trickle up and certainly impact organisms higher. Whales, dolphins and tuna all depend on lower depths to survive."
She said it could take years or even decades for the ecosystem to recover.
Oil has been spewing since the rig Deepwater Horizon exploded April 20, killing 11 people and sinking two days later. The government shortly afterward estimated the spill at 210,000 gallons -- or 5,000 barrels -- a day, a figure that has since been questioned by some scientists who fear it could be far more. BP executives have stood by the estimate while acknowledging there's no way to know for sure.
BP said Sunday it had a glimmer of success in its latest effort to stem the leak. The company said engineers used a mile-long tube to funnel some oil to the surface from the gushing well before it became dislodged.
In a news release, the company said it halted the process early Sunday after the setback, but a tanker at the surface managed to capture some oil and gas brought up by the tube. Engineers were trying Sunday to get the tube to work again deep beneath the ocean.
The company has been casting about for ways to contain the leak since it was discovered several days after the blast. First robot submarines were unable to get valves to work on machinery at the well head called the blowout preventer. Then the company failed to capture the oil with a 100-ton box after icelike crystals formed in it.
BP has also been burning small amounts of floating oil and spraying chemical dispersants above and below the surface.
A relief well, considered the permanent solution the leak, is still being drilled and is months away from completion.