BEAUTY OF UNDERWATER

"Coral” is actually the skeletal remains secreted by small marine polyps. Coral is actually a tiny animal that looks like an upside-down jellyfish; It is in the same family as a jellyfish, classified as a benthic cnidarian. There are hundreds of species of corals, divided into two general categories, soft corals and hard corals. Soft Corals are treelike and flexible. Hard corals are the reef building corals we are most familiar with. Unless otherwise specified, “coral” will refer to “hard corals”.

Zooxanthellae:
Zooxanthellae is an algae essential to the survival of coral reefs. They live inside coral and share a symbiotic relationship with them. Zooxanthellae provide oxygen and other nutrients to the coral polyps and the polyps give the algae the carbon dioxide they need to survive. Zooxanthellae also give coral its beautiful color. Without Zooxanthellae, Coral have clear bodies and white skeletons.

The Formation of the Reef:
Coral Reefs require specific conditions to thrive. They form in shallow (depths of less than 27 meters) clear water where the sunlight can easily reach them. This is important because the zooxanthellae need sunlight to perform photosynthesis. They require a fairly narrow range of temperatures (between about 20 and 30 degrees Celsius) which is why they form in warm geographic regions. They require a salinity between 34 and 37 parts per 1000, so they don’t do well near freshwater runoffs or in conditions where the water conditions change a lot. Almost all reefs grow in shallow waters bordering land, making them very vulnerable to anthropogenic fluxes.

The Necessity of Coral to the Coral Reef:
Though coral reefs are not composed solely of coral, the survival of the organisms in the reef habitat is dependent above all on the survival of the coral formations. When the health of the coral is threatened, the existence of every other species is threatened, too. The destruction of coral is leading to the endangerment and extinction of thousands of other species.

The Destruction of Coral Reefs
Coral reefs are being destroyed by anthropogenic fluxes in their environment. These fluxes are caused both directly by people who have physical contact with the reefs and by all other people who contribute to earth’s pollution.

Direct Contact: Fishing
Humans destroy coral reefs directly through unfriendly fishing habits. Many coral reefs are overfished, destroying their sustainability. In other areas, practices like cyanide fishing and blast fishing destroy reefs. Cyanide fishing is a method in which divers squirt cyanide into reef crevices and onto fish, stunning them and making them easy to catch. Small organisms, especially coral polyps, are killed by the cyanide in this process. Blast fishing, in which explosives or gun shots are sent into the reefs, can completely destroy the reef structure.

Pollution: Increased CO2
Increases in the amounts of carbon dioxide found in water have had an adverse effect on coral. The Carbon Dioxide seems to be dissolving the coral skeletons and making them much weaker. The process has been compared to osteoporosis in humans, and is leaving the fragile coral structures weak and even more vulnerable to anthropogenic fluxes.

Here are some pictures of coral reef structures