Twice an Exxon Valdez spill worth of oil seeps into the Gulf of Mexico every year, according to a new study that will be presented January 27 at the Ocean Sciences Meeting in San Antonio, Texas.
But the oil isn't destroying habitats or wiping out ocean life. The ooze is a natural phenomena that's been going on for many thousands of years, according to Roger Mitc , Vice President of Program Development at the Earth Satellite Corporation (EarthSat) in Rockville Md. "The wildlife have adapted and evolved and have no problem dealing with the oil," he said.
Oil that finds its way to the surface from natural seeps gets broken down by bacteria and ends up as carbon dioxide, a greenhouse gas. So knowing the amount of fossil fuel that turns to carbon dioxide naturally is important for understanding how much humans may be changing the climate by burning oil and gas.
Using a technique they developed in the early 1990s to help explore for oil in the deep ocean, Earth Satellite Corporation scientists found that there are over 600 different areas where oil oozes from rocks underlying the Gulf of Mexico. The oil bubbles up from a cracks in ocean bottom sediments and spreads out with the wind to an to an area covering about 4 square miles.
"On water, oil has this wonderful property of spreading out really thin," said Mitc . "A gallon of oil can spread over a square mile very quickly." So what ends up on the surface is an incredibly thin slick, impossible to see with the human eye and harmless to marine animals.