High levels of mercury can poison the human body, have adverse effects on the nervous system and prevent a baby from developing normally in the womb. This is just one of the harmful chemicals that are actively absorbed by the ocean. Those of us who enjoy the occasional tuna salad sandwich or swordfish steak have been absorbing natural and industrial chemicals from the meat for a few years now suffer a lot.
Another chemical pollutant is carbonic acid. Atmospheric CO2 is absorbed by the ocean and reacts with the seawater to form carbonic acid-this makes the ocean more acidic and intolerable to a variety of species. The shells of living mollusks have even been known to dissolve in very acidic areas of the ocean. Sea creatures such as corals, shell fish, sea urchins and star fish are likely to suffer the most because higher levels of acidity makes it difficult for them to form and maintain their hard calcium carbonate skeletons and shells. For example, even under the low predictions for future carbon dioxide emissions into the atmosphere, the combined effects of climate change and ocean acidification mean that corals could be rare on tropical and subtropical reefs, such as the Great Barrier Reef, by 2050.
Some poisons are intentionally released into the water. Cyanide(氰化物)or pesticides are released in designated areas known to harbor fish and the stunned fish are scooped up in nets and sorted. Even though the poisons dont always kill the fish, they destroy smaller organisms including the coral reef building animals. Weve already lost 20-30% of all coral reefs. If we continue to impact the ocean like we are, another 50% of coral will die off within the next decade.
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