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 constantly running off land into water. These chemicals; DDT, PCBs, and dioxins belong to a family of industrial and agricultural chemicals that do not brake down easily in our environment. When these chemicals enter the ocean they are first absorbed by phytoplankton and zooplankton. These planktons are an important part of a fish?s diet, therefore; fish eat them and the toxic chemicals are stored in the fish?s fatty tissue. Because fish are low on the food chain, each time the toxic chemicals are passed on from predator to predator the concentration gets higher. High concentrations of these chemicals cause premature birth , birth defects, nerve damage, learning disabilities, and remain in the fatty tissue of marine animals. Another major pollutant found in our oceans is heavy metals. Heavy metals are dense elements such as lead, mercury, and cadmium. Each of these elements has a different and harmful effect on sea life. Lead can make...
