Obvious oil spills, like the 168,000 gallons (635,000 liters) of oil that leaked into Galveston Bay on Saturday, usually make national news, accompanied by pictures of oil-blackened wildlife.
But such publicized events account for only a small part of the total amount of oil pollution in the oceans—and many of the other sources, such as automobile oil, go largely unnoticed, scientists say.
In fact, of the tens of millions of gallons of oil that enter North American oceans each year due to human activities, only 8 percent comes from tanker or oil pipeline spills, according to the 2003 book Oil in the Sea III by the U.S. National Research Council of the National Academy of Sciences, which is still considered the authority on oil-spill data.
Most oil pollution is “different than the pictures you see of beaches covered with tar and ducks getting stuck in it,” said David Valentine, a biogeochemist at the University of California, Santa Barbara. (Read more about how pollution harms the oceans.)
Here are three little-reported sources of oil that contribute to oil pollution in North American oceans.
1. Natural Seeps
Natural seeps of oil underneath the Earth’s surface account for 60 percent of the estimated total load in North American waters and 40 percent worldwide, according to the National Academy of Sciences.
These leakages occur when oil—which is lighter than water—escapes into the water column from highly pressurized seafloor rock. (Read about Gulf of Mexico seeps.)
Off Santa Barbara, California, some 20 to 25 tons of oil flows from seafloor cracks daily—making it one of the world’s largest seeps.
Read the full story here.
A barge that spilled 168,000 gallons (635,000 liters) of oil Saturday into Galveston Bay is threatening a refuge that’s crucial habitat for thousands of birds, experts say.
The spill occurred when the barge collided with a ship in the Houston Ship Channel near Texas City, on the western coast of Galveston Bay.
The area is about 8 miles (13 kilometers) from the Bolivar Peninsula, which is home to the Bolivar Flats Shorebird Sanctuary, a preserved area of marshy mudflats that’s home to a variety of geese, ducks, herons, and other waterbirds.
The government’s cleanup efforts began immediately, with 24 response vessels working to skim the oil and to stop the leak from the damaged barge, which was carrying more than 900,000 gallons (3.4 million liters) of oil.
About 69,000 feet (21,000 meters) of oil-absorbing boom have been placed around the site of the spill and along sensitive shorelines, according to the Coast Guard.
At least 50 oiled birds have been discovered so far, though the number will likely be much higher as rescuers expand their search, said Richard Gibbons, conservation director of Houston Audubon.
Read the full story here.