Underwater Oil in Gulf Poses Threats

Underwater Oil in Gulf Poses Threats
Officials recently declared the Gulf oil spill no longer poses a risk to the East Coast. But marine scientists are worried about the oil we can't see.

THE GIST
--Government officials recently said the Gulf oil spill no longer poses a risk to the East Coast.
--Marine scientists say even if oil isn't visible on the water's surface, there may be plumes of it underwater.
--Some argue dispersants may actually inhibit microbes from eating up the oil since it may mix with sediment.


People enjoy a day on Florida's Pensacola Beach. NOAA recently declared the Gulf oil spill no longer posed a risk to Florida's coasts. Click to enlarge this

Marine scientists are disputing claims by government officials that the Gulf oil spill is diminishing and does not pose a risk to Florida and the rest of the East Coast. They believe the oil may have been pushed underwater -- and still poses a serious and lurking threat to fish and other marine life.

"Just because you don't see it on the surface or on the coast, it doesn't mean there isn't a problem," said Felicia Coleman, director of the coastal marine laboratory at Florida State University.

"I want to know what's happening with dispersants and dispersed oil. If there are large plumes of oil underwater we might not be able to see for some time."

On July 27, NOAA administrator Jane Lubchenco released a statement that "the coast remains clear" for southern Florida, the Florida Keys and the Eastern Seaboard.

"With the flow stopped and the loop current a considerable distance away, the light sheen remaining on the Gulf's surface will continue to biodegrade and disperse, but will not travel far," Lubchenco said.

State officials have re-opened some coastal fishing grounds, and BP has also started redeploying some of its boom along the Gulf coast, raising fears among some local officials that it is abandoning the clean-up effort.

But other ocean scientists say it's too early to declare victory.

They point to new estimates that the BP well actually spewed out 206 million gallons of oil since April 20, making it larger than the previous biggest spill, the Ixtoc I blowout in 1979 that resulted in 135 million gallons.

In fact, Larry McKinney knows from experience that oil can resurface when you least expect it. That's what happened when he was a young scientist working on the Ixtoc spill.

"There are so many parallels," said McKinney, now director of the Harte Institute for Gulf of Mexico Studies at Texas A&M, Corpus Christi.

McKinney said that similar dispersants were used to break up the Ixtoc oil, which later washed ashore onto Texas beaches. Now, McKinney says he worries that the BP oil could bind with sediment particles and sink to the sea floor. That will make it tougher for microbes to decompose the oil.

"It's a race," McKinney said. "Can the microbial activity eat up the oil before it mixes with sediments and sinks?" McKinney is concerned that there could be a significant amount of oil coating the continental shelf.

McKinney said he believes that as a result, the oil spill may have increased the size of the so-called "dead zone" of oxygen-starved water off the coast of Louisiana and Texas. Much of the dead zone -- which is toxic to all marine life -- is caused by agricultural runoff from Midwest farms flowing out the Mississippi River.

Researchers at the Louisiana Marine Consortium announced Monday that the annual zone now is the size of the state of Massachusetts and is the largest in 25 years. Consortium researchers were hesitant to blame the BP spill, but McKinney and others say the oil increased microbial activity, and robbed the ocean of oxygen.

"BP used a lot of dispersant and the oil went someplace," McKinney said. "If you have that going on, there's no way that you cannot reduce oxygen levels as the result of that activity."

Paul Anastas, assistant administrator of the U.S. Environmental Protection Agency, defended BP's use of dispersants. While there may be negative effects underwater, the goal was to protect coastal wetlands.

"Once it makes it to shore," Anastas said Monday, "there's more of an impact on sensitive ecosystems that is extremely difficult to clean up."