by Hannah Hoag
Oil spills haven't been in the news much lately, but that doesn't mean they are not happening. They're just occurring in quieter but possibly more insidious ways, says George Hunt, an ocean ecologist at the University of California at Irvine. According to a recent National Research Council study, which Hunt helped produce, 76 million gallons of petroleum foul the North American coast each year. More than half of that amount seeps naturally from Earth's crust. Transportation-related spills, including tanker accidents, account for less than 3 million gallons. The overwhelming majority of human-generated spills result from recreational boating and urban runoff (such as motor oil washed off pavement), which send 25 million gallons of oil into the environment each year. Because pleasure boats are used mostly near the shore during the spring and summer months, when marine creatures are growing and maturing, the damage they cause may be especially acute. "Like real estate, oil spills are about location, location, location, and timing," Hunt says.
Graphic by Matt Zang