Zooxanthellae Symbiosis

Zooxanthellae Symbiosis Begins

 

Zooxanthellae symbiosis begins by microscopic algae (zooxanthellae) entering the coral through the coral’s water column. Technically, the coral ingests the algae, where the next step in typical ingestion is usually digestion. The latter does not occur in zooxanthellae symbiosis, and instead the algae get to work.

 

Zooxanthellae Symbiosis Benefits to Corals

 

Once inside the coral, the algae sets up shop under the skin, lodged under the tissue of the coral where it is in the direct path of sunlight that comes in at the top of each polyp. Zooxanthellae symbiosis includes the process of photosynthesis, which the algae are responsible for generating. The produced nutrients and energy are passed on to the host organism during zooxanthellae symbiosis, which uses the nutrients for its own survival and in energy in building its carbon skeleton. Over time, zooxanthellae symbiosis is directly related to the creation of entire reef systems.

Zooxanthellae Symbiosis Benefits to Algae

But zooxanthellae symbiosis doesn’t stop there. Part of the zooxanthellae symbiosis process includes the waste byproducts that are given off from the coral’s metabolism. These products are absorbed by the algae themselves, which are used in zooxanthellae symbiosis to fuel its own energy needs. In essence, the waste products are just being recycles back into the original process of zooxanthellae symbiosis, and literally everything is put to use in the end.

Limits to Zooxanthellae Symbiosis

Of course, there has to be a system of balances in zooxanthellae symbiosis. The algae cannot continue to multiply endlessly and produce excess amounts of energy. To make sure the algae’s growth is kept in check, part of zooxanthellae symbiosis includes giving the coral some control over the algae population. One way that the corals ensure this occurs is by limiting the amount of waste that the algae can use for its own purposes. Another way is by only allowing a percentage of available light to the algae for photosynthesis. All of these systems are extremely important to maintaining equilibrium of zooxanthellae symbiosis.

Threats to Zooxanthellae Symbiosis

Unplanned disturbances do come up from time to time, making zooxanthellae symbiosis off balance and at risk for death. For example, when a coral becomes stressed from excessive temperature changes or a bacterial infection, the algae are programmed to immediately flee its host. While the algae themselves will continue to exist outside of the coral and will eventually be ingested by another animal, the coral is not so lucky. Without another form of zooxanthellae symbiosis, the coral will most likely die.