NEW ORLEANS (AP) - In the nearly two weeks since a temporary cap

stopped BP's gusher at the bottom of the Gulf of Mexico, not much

oil has been showing up on the surface of the water.

Scientists caution that doesn't mean the crude is gone. There's

still a lot of it in the Gulf, though no one is sure quite how much

or exactly where it is.

"You know it didn't just disappear," said Ernst Peebles, a

biological oceanographer at the University of South Florida. "We

expect that is has been dispersed pretty far by now."

Jane Lubchenco, the head of the National Oceanic and Atmospheric

Administration, said government and independent scientists have

been working hard to figure out where the oil might be, but don't

yet have numbers. Some is still washing up on beaches and in

coastal wetlands, but not in the quantities it was a few weeks ago.

Scientists do know that more than 600 miles of coastline has

been oiled in the nearly 100 days since the April 20 explosion of

the offshore oil rig Deepwater Horizon.

They estimate that between 107 million gallons and 184 million

gallons spewed into the Gulf before the cap stopped the flow July

15. The permanent solution, using a relief well to shoot in mud and

cement, is still several weeks away.

So far, officials say they have recovered 34.6 million gallons

of oily water using skimmer boats and burned about 11.1 million

gallons off the sea surface.

So where's the rest?

Scientists are worried that much of it has been trapped below

the surface after more than 770,000 gallons of chemical dispersant

were used to break up the oil a mile deep. They have found evidence

of massive clouds of oil suspended in the water.

"What is down there is a smaller particle," said chemical

oceanographer John Kessler from Texas A&M University. "You can't

think of it as thick, nasty crude."

Kessler sampled the waters around the broken well and found high

natural gas levels more than 3,000 feet below the surface and

miles-long underwater oil plumes.

Scientists want to know how fast the oil is being eaten by

microbes, how fast it is being diluted, whether it is sinking to

the bottom and where it is being carried off to. Scientists say

large amounts of oil trapped in the subsurface could contaminate

the food chain and deplete oxygen.

Lubchenco, a marine scientist, said the oil was not sinking to

the bottom.

"As far as we can determine it is primarily in the water column

itself, not sitting on the seafloor," Lubchenco said.

She also said the oil beneath the surface appears to be

biodegrading very quickly, which she called a good sign.

Thomas Bianchi, a geochemist and oceanographer at Texas A&M

University, said that because the dispersants have pushed oil

underwater, scientists may be past the point where they can track

it from the air.

"Now it's time to look at the molecular and microbial food

web," he said. "We may be beyond people in white suits and

booms."

He added: "There's no way to clean up water at that level in a

large basin like the Gulf or these estuaries. You have to live with

nature's ability to clean it up."