Marine Contamination and Pollution
According to the United Nations Joint Group of Experts on
the Scientific Aspects of Marine Pollution (GESAMP) of 1972,
marine pollution is ?the introduction by man directly or indirectly,
of substances or energy to the marine environment resulting in deleterious effects such as harm to living resources, hazards to human health; hindrance of marine activities including fishing, impairing the quality for use of sea water, and reduction of amenities?(Clark 3). Since the beginning of modern civilization, man has continuously polluted the oceans. As more and more pollution entered the Earth?s oceans and problems became evident, man has been given the obligation to prevent further damage. Sewage, marine debris, toxic chemicals, heavy metals, oil, and radioactive materials constitute six major categories of marine pollutants that mankind needs to prevent from entering the worlds oceans.
Sewage has a short lifespan, it decomposes due to microscopic organisms like bacteria and fungi. However, in the respiration process microorganisms consume oxygen, creating ?biological oxygen demand?(Johnston 56). If there is too little oxygen in the water to support the biological oxygen demand for these biodegraders, they die and so do all the plants and animals that depend on them for food. When raw sewage is dumped into an area without strong currents to disperse it, the oxygen is likely to be used up. When this happens, the only form of decomposition that can take place is anaerobic which takes a very long time. This process is called eutrophication (Clark 5). When nutrient rich sewage enters the ocean, an extreme overgrowth of toxic phytoplankton. This process causes what is known as red-tides that kill many forms of marine life.
Marine debris is another form of pollution that is a major threat to the earth?s oceans. Marine debris consists of discarded plastic, glass, and metal that does not easily decompose. Some debris such as abandoned ships and old cars that sink attract fish because they form artificial reefs. Some artificial reefs have been purposely made by humans out of sinking marine debris for the sole purpose of providing sea life with an ecosystem. The pollution problem is more centered around floating marine debris such as plastic. Because plastic floats it constitutes a threat to sea birds and mammals who either eat it or become entangled in it. Each year 30,000 northern fur seals as well as hundreds of thousands of other marine animals die due to being entangled in discarded plastic(Johnston 63). These plastics when eaten can lodge in the intestines and stomach to block the digestive tract to cause malnutrition and death. Not only does marine debris effect sea life, but humans as well. Marine debris interferes with ship navigation and litters beaches along coastal water.
Toxic chemicals are extremely hazardous to the oceans. Three of the most deadly chemicals are...