Probably the single non-human threat caused to the coral reef is the algae. Researchers are constantly surveying the coral reefs for algae or other threats all around the world. Some surveys done around the US Pacific islands show that the coral reef is threatened by algae population consisting of turf algae, coralline algae and macroalgae. The most harmful human activities that affect the coral reef are probably the most unchecked as well. Pollution and over-fishing is the main concern of scientists and biologists around the world. Another problem that can cause the physical destruction of the coral reef is boat and shipping traffic.
Also poisoning is another factor for the coral reef. It has been discovered that the live fish trade companies have been implicated as a driver of decline in the coral reef due to the use of poisons like cyanide or other chemicals in the capture of small fishes. According to the Nature Conservancy organization, the predictions look pretty grim as it is predicted that 70 percent of the world's coral reef to have disappeared in 50 years. There are a lot of other factors affecting the coral reef. There are some pretty serious methods of fishing that can cause harm and death to a coral reef. Some of these methods include net fishing, cyanide fishing, dynamite fishing or bleaching. Bleaching is the newest threat to the coral reef. During the 1998 - 2004 weather phenomena known as El Nino, the sea surface temperature rose much above normal temperature. Caused by global warming, bleaching killed a lot of coral reefs and marine life. Also another critical factor for coral reef death is the ocean acidification. The pH of the ocean water and the decrease of it is a long term concern that has shown to affect the coral reef.
