Threats to Coral reefs in the tropical ocean

A reef is a coral community consisting of several thousand organisms living together. Although it looks like a dormant underwater bush, the reef is very much alive. Reefs grow very slowly over time. In fact, an inch of coral reef takes nearly 100 years to grow! Some fishermen stun fish by squirting cyanide, a very toxic poison, into reef areas where fish seek refuge. The poison does not kill, but disorients the fish in the coral where they hide. The fisherman then rip apart the reefs with crowbars to capture the fish. In addition, cyanide kills coral polyps and the symbiotic algae and other small organisms necessary for healthy reefs. Cyanide fishing is common in the South Pacific and Southeast Asia. Untreated or improperly treated sewage promotes the growth of algae, which harms coral reefs. Touching Reefs, even slightly, can harm them. Boats and dropped anchors can cause severe damage to these fragile ecosystems. Frequent human contact kills the reefs over time. Touching Reefs, even slightly, can harm them. Boats and dropped anchors can cause severe damage to these fragile ecosystems. Frequent human contact kills the reefs over time. Silt from eroded soil in runoff water can block sunlight. Without sunlight, photosynthesis does not occur and reefs gradually die. Shock waves from blast fishing can destroy coral reefs.