What do Coral Reefs need to Survive?

Coral reefs need four main basic needs to survive;water quality, food , light and water movement. However corals can be ''choosy''. Species within any given genus can have widely varied light, current, water quality, or other special needs.

Water quality-

• Minimum level of calcium is 400ppm and the ideal level is 450ppm. Strontium, Iodine and magnesium is also needed.
• Ammonia,which can be a toxic to fishes and other aquatic life, should be at near zero.
• Nitrite, an intermediate oxidized ion of nitrogen, should be at zero. Nitrate , an oxidized ion of nitrogen is able to survive below 10 ppm, but zero would be best.
• Phosphate, a sald composed of the most highly oxidized acid of phosphorus , and forms an important and extensive series of compounds should be below 0.3ppm.
• Alkalinity, the capacity of water for neutralizing an acid solution.It is due to the presence of hydroxides, bicarbonates, carbonates and most of the time borates , sillicates and phosphates. It is expressed in units of milligrams per liter as mg/l. It should be 3.2 to 4.5 meq.
• The temperature should be 80 to 84°F.
• Salinity the relative concentration of dissolved salts, usually sodium chloride, in a given water 1.025 to 1.027 is considered optimal.

Food-

• Most corals are carnivorous, feeding mostly on small animals. Zooplankton which is suspended in the water column of the ocean, copepods, polychrates, chaetognaths and larvae are the more commonly consumed zooplankton items in a coral's diet. Up to 85% of this food emerges from within the reef in the evening and at night.
• Most soft corals, zooanthids and gorgonians depend almost exclusively on phytoplankton, (small water-borne plants or algae) for their nutritional needs as well as floating plankton, detritus and slow moving invertebrate larvae, rather than zooplankton, which can actively propel itself.
• Another important source of food for corals is bacterioplankton, which consists of free-living bacteria as well as the bacteria associated with various materials in the water (mucas, dead plant material, and other particulate matter) which are commonly called detritus or reef snow. Most corals feed on bacterioplankton. Materials which includes detritus, floating eggs and other materials are also known as pseudoplankton. Another category of food utilized by corals is Dissolved Organic Material, which is absorbed across cell membranes directly into the coral.
• Many of the corals with larger polyps like Cynarina and Catalaphyllia are capable of capturing and eating larger food items, including the occasional small fish. many corals may select their food based more on the size of the plankton, than its composition.

Light-

• Light is required by many coral species.
• Soft coral require less light but hard corals need more lights.
• For stone corals, without light, coral bleaching can result.

Water Movement-

• Water movement is required by many coral species.
• Some corals require a water surge to flush debris from their surface.