Coral Bleaching
Coral is an organism that lives as a colony with other colonies. Corals are often described as a sort of upside-down jellyfish. It is a very simple organism however Corals are very important for the ecosystem of the sea. On and in the coral lives algae that are called zooxanthellae. Zooanthalae produces energy in the form of glucose by using Photosynthesis and the coral uses this energy. The algae are also what give the colour to coral.
The process of a bleaching event
When a cause of bleaching event happens, the algae on the coral produces harmful chemicals for the coral instead of useful chemicals and energy. In response, the coral expels the algae from its tissue. Without the algae in the tissue, the coral looks white, hence the 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 the causes of bleaching events
- When the temperature is too hot
- When the temperature is too cold
- When coral gets exposed to freshwater
- When coral gets exposed to nutrients or pollution
- When coral gets exposed to increased sun exposure
Mass bleaching events
Bleaching events are a naturally occurring process and do 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 intensely and the coral gets less time to recover. When a bleaching event happens to a large number of coral reefs 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 events almost always occur due to temperature stress. Even a temperature rise of one degree 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.
Solutions
The rising temperature and heat waves are the cause of mass bleaching events. However, with the use of Solar geoenginering sunlight can be reflected resulting in less intense heatwaves and temperature rises. For example, the use of sea salt sprays to thicken the existing clouds even more, resulting in the whiter clouds and thus more sunlight reflection.
