Coral reef symbiosis is a unique example of how a community works. In this case the community is the coral reef community. The coral reef community is alive with symbiotic relationships from the coral itself to its surroundings.
Coral cannot live without its symbiotic relationships. Its main symbiotic relationship is with algae – a one-celled algae called zooxanthellae. Zooxanthelllae live in the polyps of the coral and through photosynthesis with the sun supply oxygen to the coral so that coral can live. This is a mutualistic symbiotic relationship in that the coral also supplies carbon dioxide to the algae which algae needs for its growth.
The sun is also involved in this symbiotic relationship since without sunshine there would be no photosynthesis and the coral would die and the algae would die. Therefore most coral reefs grow near the surface of oceans where there is the possibility of photosynthesis.
The entire coral reef community is made up of sea creatures who also form symbiotic relationships with each other. Although there are less than 0.2 percent of coral covering the ocean floor, coral reefs support 25 percent of all marine species with 5000 species of fish.
Since there is a “lack of nutrients” in coral reef communities or ecosystems, symbiosis between organisms is essential for the life of the community. Light energy in the form of photosynthesis is converted to chemical energy and supports phytoplankton,algae, and other sea plants.
The energy supplied is by photosynthesis is in the form of glycerol and glucose; and up to 95 percent of the energy of the coral is through photosynthesis. Energy is needed to build their – “cup-shaped skeleton” that supports the coral and the coral colony, which with many corals forms a reef.
However, coral also receive some of their nutrients from prey (zooplankton) they catch at night with their tentacles. This type of symbiotic relationship provides nitrogen to the coral and the algae.
Many other symbiotic relationships take place within the coral community.
Giant clams also utilize zooanthellae – zooanthellae live in the mantles of the giant clam and are responsible for the colors of the mantles. Due to the concentration of zooanthellae in their mantles, they are able to help in the production of zooanthellae which is also beneficial to the coral.
There is also a shrimp in the waters around reefs – “cleaner shrimp.” These shrimp do an inviting dance that lets other sea creatures know they are available for their cleaning service. When dangerous fish such as grouper and moray eels see the dance they become docile and allow the shrimp to clean them. The “cleaner shrimp” comb their bodies, enter their mouths and “excavate dead tissue,” and remove ectoparasites from their gills.
There are many other such symbiotic mutualistic relationships around coral reefs and even cleaning stations. Cleaner fish are usually the brighter colored species such as butterfly fish and gobies.
The symbiotic relationships in coral communities are made up of a whole variety of sea creatures that depend on each other for their survival and protection.