Published: May 17, 2010 11:56 AM EDT

      NEW ORLEANS (AP) - The oil spill in the Gulf of Mexico has
already spewed plumes over ecologically sensitive reefs, part of a
stalled marine sanctuary proposal that would have restrict drilling
in a large swath of the northern part of the vital waterway.
      Marine scientists fear that two powerful Gulf currents will
carry the oil to other reefs. The eastward flowing loop current
could spread it about 450 miles to the Florida Keys, while the
Louisiana coastal current could move the oil as far west as central
      The depth of the gushing leaks and the use of more than 560,000
gallons of chemicals to disperse the oil, including unprecedented
injections deep in the sea, have helped keep the crude beneath the
sea surface. Marine scientists say diffusing and sinking the oil
helps protect the surface species and the Gulf Coast shoreline but
increases the chance of harming deep-sea reefs, which are seen as
bellwethers for sea health.
      "At first we had a lot of concern about surface animals like
turtles, whales and dolphins," said Paul Montagna, a marine
biologist at Texas A&M University Corpus Christi who studies Gulf
reefs. "Now we're concerned about everything."
      On Sunday, researchers said computer models show oil has already
entered the loop current that could carry the toxic goo toward the
Keys, the third-longest barrier reef in the world.
      The oil is now over the western edge of a roughly 61-mile
expanse of 300-to-500-foot-deep reef south of Louisiana known as
the Pinnacles, about 25 miles north of where the Deepwater Horizon
exploded April 20, killing 11 people and starting the spill that
grows by the hour.
      The Pinnacles is one of nine coral banks and hard-bottom areas
stretching from Texas to Florida that the National Oceanic and
Atmospheric Administration tried in 2008 to get designated a marine
sanctuary called Islands in the Stream.
      This sanctuary would have restricted fishing and oil drilling
around the identified reef "islands." But the plan was put on
hold after vehement objections from Republican lawmakers, fishermen
and the oil industry.
      Scientists have found undersea plumes of oil at the spill as
much as 10 miles long, which are an unprecedented danger to the
deep sea environment, said Samantha Joye, a professor of marine
sciences at the University of Georgia.
      These plumes are being eaten by microbes thousands of feet deep,
which removes oxygen from the water.
      "Deepwater coral are abundant on the sea floor in this part of
the Gulf, and they need oxygen," said Joye, who was involved in
the plume discovery. "Without it, they can't survive."
      Experts say the well's depth and Friday's decision by the U.S.
Environmental Protection Agency to allow BP to shoot massive
amounts of dispersing chemicals deep underwater may help protect
vital marshes and wetlands on the Gulf Coast. But the tradeoff may
result in significant effects on more sea life.
      Oil mixed with the chemical agent can disperse into the water
more easily, rather than it staying on the surface, where it could
bypass deeper banks like Pinnacles, said Edward Van Vleet, a
chemical oceanography professor at the University of South Florida.
      The downside is that it causes oil to sink, coating corals and
other reef organisms and smothering them, he said.
      When the dispersed oil is broken into smaller globules, he said
they are more easily eaten by smaller reef organisms and can kill
them or cause tumors or something else harmful.
      Federal officials who oversee marine sanctuaries and fisheries
say it's too early to tell how reefs and other important habitats
may be damaged, said Dr. Jane Lubchenco, NOAA's undersecretary of
commerce for oceans.
      NOAA, which manages marine sanctuaries, is also responsible for
estimating financial costs of the spill on the sea environment and
fisheries. The Pinnacles is a significant habitat for sea life
vital to commercial fisheries such as red snapper, crab and shrimp.
      The creation of a sanctuary across hundreds of miles of the Gulf
would not have blocked oil and gas exploration where the Deepwater
Horizon exploded, said Montagna. However, he said it could have
resulted in stricter environmental regulation for reefs closest to
the spill site, and likely less drilling.
      "So you can imagine these animals that make a living on rocks,
filtering food out of the water, and the dispersants come along and
sink the oil; it's a big concern," Montagna said.
      The area also is breeding ground for sperm whales and bluefin
tuna, species not doing well, he said.
      Studies published in a 2005 National Academy of Sciences report
show that oil mixed with dispersants damaged certain corals'
reproduction and deformed their larvae. The study concluded the
federal government needed to study more before using massive
amounts of dispersants.
      Reefs are made up of living creatures that excrete a hard
calcium carbonate exoskeleton.
      Depending on the oil exposure, they can be smothered by the
pollutants or become more susceptible to bleaching, which hinders
reproduction and growth. While the warm temperatures of Florida
could speed the recovery of damaged reefs there, some problems
could be seen for a decade or more. In the deeper reefs in colder
water closer to the spill, the damage could last even longer.
      As the spill increases, the oil oozes toward other reefs that
stretch from the blowout site eastward to the Florida Keys National
Marine Sanctuary.
      The Keys exist in relatively shallow water, so the potential
exposure to the oil is higher than for deeper reefs, though BP PLC
officials say the oil would be more diffused after having broken
down during its travel over hundreds of miles.
      This week, researchers from USF and the Florida Department of
Environmental Protection are heading to the loop current to get a
"chemical fingerprint" of any oil they find to confirm it is from
the leaking well.
      "We don't expect the loop current to carry oil onto beaches,"
William Hogarth, dean of the University of South Florida's College
of Marine Science, said. "But we do have a great concern for the
      If oil reaches the Keys, it could threaten one of the country's
greatest underwater natural resources as well as its tourism
      Locals throughout the ribbon of islands not only relish their
ties to the water but rely on it to help bring in 2 million
visitors each year.
      "They're not going to come if our beaches are tarred and our
mangroves have died and it's a polluted dump," said Millard
McCleary, program director of the Key West-based Reef Relief.
"They'll go to the Bahamas or the Caymans or they'll go to
      Sedensky reported from Key West, Fla. Associated Press writer
Janet McConnaughey in New Orleans contributed to this report.
      (Copyright 2010 by The Associated Press.  All Rights Reserved.)