The Texas spill is obvious, but automobile oil is a bigger contributor. An iridescent sheen spreads from a drop of crude oil on top of the water in the Gulf of Mexico. 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 […]