Biological And Environmental Effects Of Oil Spills Biology Essay

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An oil spill is usually defined as an unintentional or purposeful discarding of oil or petroleum products into the ocean and its coastal waters, bays, and harbors, or onto land, or into rivers or lakes (Holum). The oil is unconfined, mostly, in small yet consistent doses from tankers, industry, or on shore waste disposal (Boesh, Hersher).

Oil spills will eventually break up naturally and unsurprisingly if left unaccompanied. The natural frightful circumstances is influenced by temperature, wind, wave action, the thickness of the oil, the amount of dispersal, and the oil's tendency to form emulsions with water (Smith 1968).

Impact on biomes, ecosystem and food chain:

The impact of oil on a marine ecosystem is not similar on different organisms. Organisms living at or near the surface are impacted more than others in the area. These organisms include those in intertidal areas seabirds, and bottom dwellers. The type of oil spilled controls the extent of damage that is done to the organism. There are three classes of hydrocarbons: alkanes, alkenes, and aromatics. Alkanes, in low concentrations, cause anesthesia and narcosis, and in high concentrations, cell damage and death, in marine invertebrates. Alkenes, which are not typically found in crude oil but in refined products such as gasoline, are more toxic than alkanes, but less toxic than aromatics. Aromatics are not common in nature but they can kill ocean organisms, not only at full strength, but in diluted concentrations as well.

The harm of an oil-spill goes deeper than any sea, higher than any sky. The oil doesn't stay in one place, but moves along with the flow of the waters. The dangers of petroleum to wildlife are well established. Seabirds can become too heavily coated with oil to fly and when they try to clean the oil from their feathers with their beaks, it destroys them. Sea otters and seals contaminated with oil may suffer from injuries in the major organs and these conditions are often fatal. Animals such as eagles, bears, wolves and foxes that eat the oil-soaked carcasses washed up on the shore get themselves contaminated with the crude oil. Of course, fish can be spoiled unswervingly by the oil, or also ultimately by its consequence on the plants and organisms that make up their food chain. The effects of oil on organisms can be broken down into two subdivisions, chemical and physical. Chemical effects are caused directly by the involved components and usually take place immediately. Physical effects such as oil coating and reduction of the photosynthetic rate from oil films are indirect and can take longer to occur (Duffus 1980). In the intertidal area, physical effects of oil include smothering, abrasion, and removal and alteration of the substrate. Organisms with mucus, such as macroalgae and anemones are often unaffected by the physical effects of oil. Direct toxicity is rare in the intertidal area. Most organisms are harmed by the non-toxic results of the oil being in the environment. Oil spills also damage our fresh water supply, which humans depend on for drinking, bathing and irrigating crops. The list is endless. It's everlasting. As much damage the oil is doing to Mother Nature, we must try to get the oil out of the seas as fast as possible. This is done in a variety of methods. There are generally three basic approaches in attack oil that has spilled into the waters. The first approach is to contain the oil and remove it from the water. The first few hours after an oil-spill has occurred are the most crucial. During this time, if booms, which are long plastic or rubber barriers, are placed around the

edges of the drifting oil, the oil can be stopped from doing further damage. Then, they skim the oil, which means to remove the oil from the water's surface. From the previous disaster of the, they did try to get the oil out of the water. It's just that they missed the part about having it done as soon as possible. Seabirds can also swallow the oil, which inflames the digestive track. After the digestive track becomes tender, the bird is not hungry so it does not eat and eventually dies from undernourishment and hunger. Possibly less than twenty percent of birds that are affected by oil have survived. Birds are the only victims that are known for certain to be affected by regular premeditated oil emancipation by tankers. Due to this, several populations in the northeast Atlantic face local extinction and one species of penguin is endangered with global extinction (Boesch, Hershner). Mammals and fish are not as affected as birds by oil spills. Mammals, such as pinnipeds and cetaceans are suffocated by the oil and lose their insulation when it attaches to their fur. They can also be poisoned when the oil is ingested (Boesch, Hershner). Milk is used to clean the heads of marine mammals because it does not sting their eyes (Dorfman ). Fish may be more resistant to the oil because their surfaces and gills have mucus that repels oil. It is also believed that fish whirls away from oil slick. Fish are usually affected by feeding on contaminated benthic invertebrates (Boesch, Hershne). Almost any marine community is affected by ecosystem contamination. Chronic pollution can keep a community in an immature stage with a low diversity rate. High concentrations can be found even outside of oil spill areas. Although some petroleum is released naturally through seeps, the rate of petroleum released by man is higher than the natural release rate. Once hydrocarbons have tainted an ecosystem they become further determined in the food web by biomagnifications. This interrupts photosynthesis, respiration, and other metabolic functions; has carcinogenic and mutagenic potentials; and can demolish normal behavior patterns associated with survival, feeding, schooling, reproduction and development in the entire ecosystem food web (Boesch, Hershner).These problems will continue until oil spills can be prevented.

There are eight major processes in the usual degradation. The primary step is spreading and motion. This step can also be defined into three smaller steps and they are gravity, viscous forces, and surface tension. Gravity originally extends the oil into a smooth layer across the surface. Viscous forces later creates even more spreading. At last, the oil gets spread into a monomolecular slick by the exterior pressure of the water. The evaporation amount is superior when the slick is spread out to a greater degree. Through evaporation approximately 50% of hydrocarbons are removed from the oil within 10 days (Beer 1983). With crude oil, twenty-five percent of its volume can be evaporated during the first few days. Evaporation continues at a diminishing rate for several weeks (Smith 1968) .The sixth part of this process is called photochemical oxidation and it takes place when the daylight persuades chemical changes in the oil and it begins to solidify and the next step in the natural degradation of oil is sedimentation. As the density continues to increase, the oil and its other components become heavier than water, so they eventually sink to the bottom of the ocean (Beer 1983). The final step in the process is bacterial degradation. The remaining sediments on the ocean bottom are broken up by bacteria. If an oil spill stays at sea for longer than three months, only fifteen percent of the original amount should theoretically remain.

Responses to Environmental Disasters and Recovery Process:

Oil contamination is usually triggered from the cleanup of ships. This chaos could have been avoided if firmed guidelines were followed and appropriate initiatives were taken. It's not unlikely that every year majority of the oil is usually spilled through the North Sea. Unfortunately workers have been usually dumping the products both on land and in the sea. Sewers and river also make it worse by discharging a lot of oil in the sea. Government needs to take appropriate schemes to prevent from further contamination by reprocessing rather than just dispensing it down to exhaust or concealing the products in the enclosure.

There are a variety of cleanup methods we can use for oil spills. These contain repression by barriers and removing the floating oil physically, soaking up the concentrated oil, chemical dispersal, and vapor cleaning. Containment and deletion is the most desirable method to avoid biological damage, because no foreign substances are added to the water. A downside is that booms and skimmers to remove the oil can only be used in calm water. This procedure must take place immediately after the accident to stop sedimentation. North America uses absorbents most of the time. The recuperation process for this oil spill will also take the longest period of time. Recovery time could be centuries or not at all per researchers.

Work Citations

1)Boesch D., Hershner C., Milgram J. 1974. Oil Spills and the Marine Environment. Cambridge, MA: Ballinger Publication Comp.

2) Boilema A, Cairns J. 1984. "Restoration of Habitats Impacted By Oil Spills". Boston: Butterworth Publishers.

3) Dorfman A. 2001. "A Sticky Situation". Time for Kids

4) Duffus J. 1980. "Environmental Toxicology". New York: Halsted Press.

5) Holum J. 1977. "Topics and Terms in Environmental Problems". New York: John Wiley and Sons.

6) Smith J.E. 1968. "Torrey Canyon Pollution and Marine Life". Cambridge, Great Britain: University Printing House