Corals arent only a food source. There is also a clear connection between tsunamis(海啸)and storm events having a much greater impact on eroding coastlines than healthy ones. Healthy reefs protect coastlines from the damage of massive waves. During the recent tsunami in Indonesia, for example, coastlines protected by reefs and mangrove forests remained intact and experienced much less impact than coasts that did not have reefs.
Pollution is a major threat to the ocean. Pollution comes in many forms and shapes, but most have one thing in common: Almost all ocean pollutants stem from land based human activity. Waste produced on land eventually finds its way to the ocean. It is not uncommon to find beaches littered with plastic bags and bottles that finally came to rest on shores. Rivers carry dirt, oils, sewage and chemicals out to sea. Garbage also finds its way to ocean. Seeing plastic bags floating around the water instead of fish is not a pretty sight. Washed up garbage on the sand will definitely ruin a nice beach vacation. With many third-world countries relying on tourism for income, it is important to maintain the ocean and beaches in as pristine a condition as possible.
Chemicals are constantly absorbed by the ocean. Chemicals have a drastic effect on fish populations and the fishing industry. Chemicals absorbed by animals at sea will also harm the human population that consumes them. Mercury is a chemical now commonly found in larger predatory fish such as tuna and shark. It occurs naturally in the environment and also can be released into the air through industrial pollution. Mercury falls from the air and can accumulate in streams and oceans. Bacteria in the water cause chemical changes that transform the mercury into methylmercury. It is this type of mercury(水银, 汞) that can be harmful to unborn babies and young children. Fish absorb the methylmercury as they feed in these waters. Methylmercury builds up in the tissue of some types of fish and shellfish more than others depending on what the fish eat.
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