Half the oil that enters the sea comes form natural sources. It is consumed by organisms able to metabolize hydrocarbons. Source: http://www.whoi.edu/oilinocea

Half the oil that enters the sea comes form natural sources. It is consumed by organisms able to metabolize hydrocarbons. Source: http://www.whoi.edu/oilinocean/page.do?pid=51880 http://www.whoi.edu/oilinocean/page.do?pid=51880 Thus, I don't think anyone would expect the world to be covered in oil.