NEW ORLEANS (CN) - Marine scientists have found another giant plume deep beneath the Gulf's surface believed to be oil and stretching 22 miles northeast from BP's gushing wellhead. The thick mass is headed toward an underwater canyon whose currents feed marine life in the waters off Florida. Scientists fear these oil clouds will create giant dead zones in the Gulf by suffocating large marine life and poisoning tiny creatures at the bottom of the food chain.
The discovery was made Thursday by researchers on the University of South Florida College of Marine Science's Weatherbird II vessel. It is the second significant plume found since the April 20 explosion of the Deepwater Horizon that killed 11 and injured 17 others.
The thick plume is more than 6 miles wide, according to David Hollander, associate professor of chemical oceanography at the Florida school. It was detected by its dense concentration of hydrocarbons just beneath the water's surface down to about 3,300 feet.
Hollander's team said the thickest amount of hydrocarbons was detected at about 1,300 feet in the same spot on two separate days this week. Discovery of the plume was important, Hollander said, because it confirmed that the substance in the water was not naturally occurring and that the plume was at its highest concentration in deeper waters.
The researchers will use further testing to determine whether the hydrocarbons they found are the result of dispersants or a natural coagulation of the oil as it traveled away from the well.
Many scientists worry these plumes are the result of unprecedented use of chemical dispersants to break up the oil a mile undersea at the site of the leak.
Oil companies such as BP use chemical dispersants to break up oil, but dispersant use has never been as significant as the more than 600,000 gallons of chemicals BP has far dumped on the millions of gallons of crude oil that have leaked into the Gulf of Mexico.
Hollander told the San Francisco Chronicle that there are two elements to the plume. "The plume reaching waters on the continental shelf could have toxic effects on fish larvae, and we may also see a long term response as it cascades up the food web," he said.
The first plume found by researchers May 16 was traveling from the well southwest into the open sea. It launched concerns that deepwater marine life would suffocate, but this new mass is headed into shallower waters inland, where many fish and other species reproduce.
Hollander said the oil they detected has dissolved into the water and is no longer visible, causing fears among researchers that the toxicity from the oil and dispersants could pose a monumental threat to fish larvae and creatures that filter the water for food.
The mass was nearing a large underwater canyon whose currents are crucial to the food chain in Gulf waters off Florida, and could harm the tiny plants and animals that feed larger organisms by inundating them with the toxic chemicals, another researcher said.
The DeSoto Canyon off the Florida Panhandle sends nutrient-rich water from the deep sea up to shallower waters, said Larry McKinney, executive director of the Harte Research Institute for Gulf of Mexico Studies at Texas A&M University-Corpus Christi.
In the best-case scenario, McKinney said, oil on the current would rise close enough to the surface to be broken down by sunlight. But if the plume does not break down, the mass could continue on as a toxic cloud along the west coast of Florida toward the Keys.
The plumes could poison and suffocate all kinds of sea life for up to a decade, Samantha Joye, a professor of marine sciences at the University of Georgia, told The Associated Press last week. The combination of oily water and oxygen depletion in the lower depths can "interrupt the food chain at the lowest level, and will trickle" up the chain, she said. Whales, dolphins and tuna could all be affected.
Richard Charter, government relations consultant for Defenders of Wildlife Action Fund, told Mother Jones last week that oil companies use dispersants to sink the oil in part because they "want to make the visible part of the oil spill disappear -- for political reasons, limiting the liability to the spillers." But, Charter says, "if we were looking at food chain impacts and biomagnifications in the marine ecosystem, we probably never would have invented" them.
Federal scientists estimate that between 18 million and 28 million gallons of oil have already spilled into the Gulf of Mexico, eclipsing the 11 million gallons spilled by the Exxon Valdez off the coast of Alaska in 1989.
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