the effects of oil spill in the marine ecosystem

These components affect living organisms in many ways. Some of the soluble components and emulsions are poisonous, particularly to small organisms that do not have protective coverings or shells- Fish larvae, single celled algae and many kinds of plankton are vulnerable and these are the basic foundation of the marine food chain. In shallow water these toxic substances may directly kill algae, coral and sea grasses. These components may also be passed in the food chain or directly ingested or absorbed through the gills of fish and other larger marine organisms. The effect may be to kill the animal or contaminate its tissues. A thick film of oil on the sea surface may reduce sunlight penetration and reduce photosynthesis.
Small particles and emulsions may be ingested or block the feeding mechanisms of invertebrates such as oysters, starfish, sponges and corals. These particles also may have toxic components, so the effects can be physical, chemical or both.
The most dramatic impact of oil spills is the coating of larger animals with oil. Animals that breathe at the surface like dolphins, sea turtles and manatees may inhale oil and toxic vapors. Sticky oil may also coat their bodies. Coating with oil is particularly devastating to birds. Even a thin coat of oil compromises the waterproof quality of feathers, causing the bird to become water logged and loose heat. Animals, like some sea turtles, that feed at or near the surface may ingest tar balls and particles that then physically blocks their intestines and may be toxic as well.
At the shoreline, shallow waters and coastal estuaries and marshes, the impact of the layer of oil, floating and suspended emulsion and particles can be devastating, coating plants and benthic animals like corals, crabs and shell fish, preventing photosynthesis and breathing and blocking filter feeding mechanisms. These materials become mixed into shoreline sediments and remain in the system for years.
‘Dispersants’ are detergent