When boaters come too close to shore where coral reef systems exist, the propeller can strike the corals and break through them. Snorkelers and scuba divers swim along reef systems and they often interact with the corals, unaware that the slightest touch can kill the corals by introducing foreign bacteria. Some divers also dive with the goal of returning home with corals as a souvenir. Some divers make money from the sale of coral. .
Another reason why coral reefs are dying is due to coral bleaching. Coral bleaching occurs when water conditions become favorable for the algae that live in coral polyps to thrive and eventually leave the polyps because it no longer needs them to survive. When algae leaves the coral, the polyps become vulnerable to disease and corals starve because their algae food source is no longer available. .
The reason water conditions become more favorable for algae is because ocean temperatures are rising due to global warming. According to an article in TIME Magazine regarding the ecological impacts on coral reefs, water temperatures must remain between 68 °F to 82 °F in order for corals to survive (Walsh). Most of the sun's heat is held by the world's oceans, but because of air pollution, the heat is unevenly distributed, with more heat impacting the earth's surface. This is causing ocean temperatures to rise to levels that eventually destroys coral reefs.
Another reason why coral reefs are quickly disappearing is pollution and toxic chemicals that are making their way to rivers and oceans. Toxic waste are poisonous materials that are being dumped by industries (and individuals) into sources of water that flow to the ocean. Toxic waste is the most harmful form of pollution and is destroying many forms of ocean life. When toxic waste harms an organism, it can quickly be passed up the food chain and eventually end up on our dinner tables! .
In the food chain, one toxic organism is eaten by another.
