Coral Bleaching
Coral is a organism that lives as a colonie with other colonies. Corals are often described as a sort of opside down jellyfish. It is a very simple organisms however Corals are very important for the ecosystem of the sea. On and in the coral lives algae that is called zooxanthellae. Zooanthalae produce energy in the form of glucose by using Photosynthesis and the coral uses this energy. The algae is also what gives the color to coral.
The process of a bleaching event
When a cause of bleaching event happens, the alagae on the coral produces harmufl chemicals for the coral instead of useful chemicals and energy. As response the coral expels the algae from its tissue. Without the algae in the tissue the coral looks white, hence te name bleaching event because it looks like the coral has been bleached. Bleached coral is not that but bleached corals are at more risk of starvation and diseases which will result in dead corals.
What are causes of bleaching events
- When the temperature is too hot
- When the temperature is too cold
- When coral gets exposed to fresh water
- When coral gets exposed to nutrients or pollution
- When coral gets exposed to increased sun exposure
Mass bleaching events
Bleaching events is naturally occurring process and does not do much harm to coral reefs as long as the coral gets enough time to recover. However the bleaching events are occurring more often and intenserer and the coral gets less time to recover. When a bleaching event happens to a large amount of coral reef at the same time it is called a mass bleaching event. Mass bleaching events are a threat to coral reefs because it takes more time to recover and it has chances are higher for corals to die. Mass bleaching event almos always occur due to temperature stress. Even a temperature rise of one degrees Celsius for only a few weeks can trigger bleaching. Climate change is a huge cause of mass bleaching events and is threatening coral reefs from all over the world.
