Particularly in coastal areas this oil would persist were it not for the bacteria that eat it. Other microorganisms metabolize oil too, as do higher organisms. These microorganisms require both the existence of oxygen and certain minerals to metabolize oil. They are able to attack the oil best when it is mixed with water. Even highway blacktop gets eaten in time, but its dryness, the lack of minerals such as nitrogen and the large size of the asphaltene molecules in blacktop make it tough chewing for the bugs.
Many hydrocarbons dissolve only slowly in water.
Others such as the aromatic compounds like benzene are more soluble, and these are toxic to living cells. The aromatic hydrocarbons can attack the fat-like membranes surrounding cells and adversely affect their normal functioning. But, fortunately, bacteria and other microorganisms composing the marine flora are able to feed upon the wide variety of compounds found in petroleum. The ocean water itself aids the process by helping to transport oxygen and minerals to the microorganisms. However, even without such assistance, the oceans have a high capacity to biodegrade petroleum.