Coral Bleaching

Corals are tiny animals that live in colonies, forming what we know as coral reefs. Coral reefs also include many other biological communities, creating a diverse ecosystem. Corals depend on a symbiotic relationship with a type of algae capable of performing photosynthesis, known as zooxanthellae.

It is also responsible for giving corals their color. Zooxanthellae performs photosynthesis and produces food, which it shares with the coral. The coral, in turn provides the algae with protection and access to sunlight. Zooxanthellae are accountable for 90% of a coral’s nourishment.

However, under stressful conditions, corals may actually expel their algae. This is known as coral bleaching. Without their algae, the white coral skeleton is exposed and the organism slowly starves and eventually dies.

Coral bleaching has several causes. Among the most common are increases in water temperature and ocean acidification. Coral reefs can only tolerate a very narrow range of water conditions. This means that they cannot withstand extreme temperature changes. Increased acidity in the ocean water also acts as a stress factor. Corals that are able to survive the stressful period, usually take years to recover and without the algae they suffer a loss of nourishment, which affects all reef-dwellers.

Coral reefs are important to preserve because they are home to many other organisms such as oysters, clams, crabs, shrimp, sea urchin, sea stars, jellyfish, anemones, and many fish species. The death of one of these reefs means the loss of one nature’s most diverse and productive ecosystems.

Ada Bersoza