About 380 million gallons of oil enter the world's oceans and coastal waterways each year from natural and human sources. This illustration shows the approximate worldwide percentages arriving from each source. The relative inputs of oil can vary significantly in different parts of the world. The percentages for transportation include oil lost specifically in oil/petroleum commerce (tankers, pipelines, etc.), as well as the normal operation of all other sea-going vessels.
Satellite radar images show the extent of the 2002 Prestige oil spill along a 30-mile stretch of the northwest coast of Spain. The slick (black areas) is visible because the oil smooths the ocean surface. The surface of clean water appears bright because it scatters and reflects light back towards the satellite. Oil can have wildly different impacts depending on where it is spilled and what the weather is doing in the hours and days afterward. (Courtesy: RADARSAT / Canadian Space Agency.)
Researchers from the WHOI Marine Chemistry and Geochemistry Department collect samples of oil deposited on the shores of Falmouth, Massachusetts, following an April 2003 spill. Three generations of WHOI scientists have studied the effects of oil in the marine environment through firsthand observations of four nearby spills and smaller, chronic inputs from development and commerce in the industrialized Northeast. (Tom Kleindinst, WHOI Graphic Services.)
The everyday "normal" activities of modern industrialized societydriving, shipping, heating our buildings, operating industrial machineryput far more oil and its byproducts into the oceans than all the major spills combined. The significance of the input of oil from petroleum-fueled vehicles might even be understated, since the chronic drip of oil from millions of cars and trucks is extremely hard to measure. (Digital Vision Ltd.)