The source of marine pollution is plentiful, about eighty percent of them come from land-based activities. Some enter the ocean directly, some pollute ocean indirectly. The first pollutant that enters the ocean directly is Sewage. The used water and polluting substances that are produced by human, flow through river and directly entered the ocean. For example, about 80% of untreated …show more content…
Frist, the spill oil not only drown marine animals to dead, but also make them difficult to move and feed their children. Oil spill also floats and stay on the top of water and prevents sunlight enter the ocean, which affect their process of photosynthesis. When Marine animal stay in the oil polluted areas for a long time, their skin and eye irritation, lung and liver problems, and their reproductive system will be affected; it also cause cancer and their behavioral changes. Second, the debris in the ocean does not decompose and they stay in the ocean for years. They consume oxygen and cause the oxygen level goes down. As a result, marine animals such as whales, turtles, sharks cannot survive. The wasted and chemicals used in industries and agriculture also have an effect on the food chain. Small animals will swallow the chemicals debris, which do not dissolve and sink at the bottom of the ocean, and later on are eaten by larger animals. After that, those larger animals will be captured and eaten by human, which will cause some illness such as cancer to human