Oil spills from tankers account for only 7.7 percent of oil that ends up in the ocean, but the oil itself and the cleanup efforts designed to eliminate it can be devastating to the environment (see References 1). Oil damages wildlife through smothering, as well as by absorption, inhalation and ingestion (see References 2).
Physical Effects on Plants and Wildlife
Spilled oil initially spreads into a thin, wide layer floating on top of the water (see References 3). When sea birds and otters contact the oil slick, they become physically covered with oil (see References 2). The oil on the surface breaks down over time, and heavier elements sink to the bottom (see References 3, page 6), where they can smother aquatic plants and invertebrates, killing them outright or interfering with their reproduction and growth (see References 2).
The most toxic compounds in spilled oil tend to evaporate into the air (see References 1). Animals may inhale these toxic vapors, damaging their nervous system and organs. The oil that remains behind is far from harmless, as well — animals that ingest oil from spills may die immediately or suffer damage to their digestive tracts. (See References 3, page 8) Unfortunately, some detergents used to clean up after oil spills are themselves toxic to marine plants and animals (see References 1).
Animals that are not directly killed by an oil spill may still suffer indirectly due to habitat damage. Delicate habitats, such as coral reefs, are susceptible to poisoning or smothering by oil. Healthy coral reefs act as a nursery for other aquatic life, so their death affects several other species. Oil that enters tidal flats, marshes or mangrove forests can destroy plant life important to many other species in the area, taking years or decades to recover. (See References 3, page 7)
The Food Chain
Because eating contaminated food can cause an organism to become contaminated itself, an oil spill can affect several links in the food chain. If a fish eats oil-contaminated plankton and a human eats the fish, the oil spill affects the human indirectly (see References 2). Some animals, such as oysters, filter food from the water, which can concentrate toxins in their bodies. These toxins may disperse when water conditions improve but make them inedible for a time. (See References 1)
Based in central Missouri, Rachel Steffan has been writing since 2005. She has contributed to several online publications, specializing in sustainable agriculture, food, health and nutrition. Steffan holds a Bachelor of Science in agriculture from Truman State University.
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