The oil had seeped from reservoirs below the seafloor, leaked through cracks in the crust about 150 feet (45 meters) under water. Lighter than seawater, the escaped oil floated to the ocean surface.
account for about 50 percent of oil that ends up in the coastal environment. That’s five times as much oil as is delivered by accidental spills.
Oil and methane bubble to the ocean's surface from natural seeps off Coal Oil Point, near Santa Barbara, Ca
he Santa Barbara seeps, for example emit 5,280 to 6,600 gallons (nearly 20 to 25 tons) of oil per day, and natural seeps have been active for hundreds to thousands of years. Local Native Americans used the oil to waterproof their boats
on the oil’s journey up to the seafloor, approximately 1,000 compounds in the oil were devoured by microbes living in the rocks beneath the sea floor. Some ate the oil and created intermediate byproducts.
eaten by other microbes that likely converted the oil into natural gas.
clipped from: www.whoi.edu 
