Oil Spills
An oil spill can be defined as an accidental or deliberate dumping of oil or petroleum products into the ocean and its coastal waters, bays, and harbors, or onto land, or into rivers or lakes (Holum 1977). Between one and ten million metric tons (one metric ton is 1000 kilograms) of oil are put into the oceans every year. The oil is released, most often, in small yet consistent doses from tankers, industry, or on shore waste disposal (Boesh, Hersher, et al. 1974). Tanker spills cost the United States more than one hundred million dollars every year. Spill frequency increases proportionally with tonnage carried, in a linear manner. Non-tanker spills also increase linearly and account for thirty percent of all spills. The Atlantic area near Europe averages eight spills a year, the American area seven, and the Pacific two. Spills of more than ten thousand metric tons account for about two and a half percent of total spills, and spills above fifty thousand metric tons occur on average once a year. The average spill size is around seven thousand metric tons (Smets 1982). If left alone, oil spills will eventually break up naturally. The natural degradation is influenced by temperature, wind, wave action, the thickness of the
Emulsification is the fourth step in the natural degradation process. It is believed that this accounts for roughly five to fifteen percent of the actual bird mortalities from oil spills. Viscous forces then take over and account for even more spreading. Burning is biologically innocuous. The best prevention mechanism to help stop large spills usually associated with tankers, is by careful boat navigation (Beer 1983). The primary effect of oil on birds is the fouling of feathers, which disrupts insulation and buoyancy. Aromatics are the most immediately toxic component found in oil (Boesch, Hershmer, et. At times, when a dominant species has been removed, others can gain an advantage through atypical survival of their young, and rearrange the order of the ecosystem. The third step in natural degradation occurs when the wind and the waves cause the hydrocarbons to enter into a solution with the ocean water. The amount of time needed for total recovery depends on the structural complexity of the system and the degree of damage that was done. Bird death tolls from oil spills are recorded for the animals that reach the shore. Marine communities have a more rapid rate of succession than land communities such as forests, but it still takes several years. The next step is direct sea to air exchange. This method must be applied immediately after the accident to prevent sedimentation. Much of the ocean is contaminated to at least some degree with petroleum.
Common topics in this essay:
Pacific Spills,
Boesch Hershner,
Boikema Cairns,
Boesch Hershmer,
America Straw,
Alvaro Fernandez,
,
Boesh Hersher,
oil spills,
al 1974,
et al,
et al 1974,
hershner et al,
hershner et,
boesch hershner,
boesch hershner et,
natural degradation,
beer 1983,
crude oil,
step natural degradation,
chronic pollution,
metric tons,
thousand metric tons,
|
Acceptance Essays
