• Oil spills often have devastating effects on ocean wildlife.Ocean wonder image by doniphane dupriez from Fotolia.com
  
  Oil spills account for only 8 percent of all oil dispersed into the ocean, but they have an array of negative effects. Oil disrupts the ocean's ecosystem and poisons wildlife, sometimes eradicating entire populations. Oil spills often occur during offshore drilling and well repair. Long-term effects on the ocean depend on the type of oil spilled, as certain types behave differently than others.
  
  

Behavior of Oil

• Oil spilled into the ocean spreads quickly, remaining a cohesive mass in calm waters and breaking up if waves are choppy. The spread of oil is affected by the current, wind and waves, sometimes spreading throughout very large areas. It is also affected by the type of oil spilled; for example, oil that contains volatile organic compounds loses 20-40 percent of its mass through evaporation, becoming more viscous and dense. Some parts of oil sink, some form tar balls and some dissolve enough to become invisible. In deep water, oil forms "plumes," which look like long feathers.
  
  

Effects on Ecosystem

• Oil has a very negative effect on the ocean's ecosystem. If plants and animals are not immediately killed, their survival is compromised by the poisoning of the ocean's organic substrate by oil. When the ocean's food chain is thus interrupted, populations of wildlife in a given area are often decimated, sometimes entirely. Some oils produce degrading microbes, which, though they decrease the presence of oil, also deplete the water's supply of oxygen. If oxygen levels dip low enough many organisms suffocate.
  
  

Effects on Wildlife

• Oil spills often result in immediate, large-scale death in fish and other ocean wildlife such as amphibians and birds. Those that do not die are often contaminated or injured. Some animals are smothered by oil, which often forms a sort of "mousse." Some ingest it and others are simply exposed to too much of it through direct contact. This negatively impacts animals' behavior and reproductive systems, as well as the ocean's food chain. People often are able to rescue ocean animals and nurse them back to health, but this is doable only on a small scale.
  
  

Recovery

• It is possible to mitigate the negative effects of oil on the ocean by immediately taking action to clean up the spill. Oil may often be contained or dispersed by the introduction of microorganisms that act to dissolve it. If neither of these options is successful, time, weather and bio-degradation will eventually cause the oil to disappear without human intervention. This takes time and happens much more slowly in deep water than in shallower, coastal regions.