Coral Bleaching

If you’ve heard of coral bleaching, you might wonder what happens when corals turn white or are “bleached”.

In the event of a change in their environment, such as changes in seawater temperatures or salinity or even nutrient content, the zoox that live in corals began to get “stressed”. This would then lead to them being expelled from corals, leaving them to appear white, or in other terms, “bleached”.

Zooxanthella, otherwise known as zoox, have a symbiotic relationship with corals: they provide corals with the food they need as well as give colours their bright, attractive colours. In return, corals provide zoox with shelter.

What Causes Coral Bleaching?

Increased ocean temperature caused by climate change is the leading cause of coral bleaching. Stormwater can rapidly dilute the ocean water and runoff can carry pollutants - these can bleach near-shore corals.

Overexposure to sunlight can contribute to bleaching of shallow-water corals. Exposure to the air during extreme low tides can cause bleaching of shallow-water corals.

Are Bleached Corals Dead?

Bleached corals are not dead - they simply do not have their zoox. They are able to recover from bleaching and regain their zoox once again. However, in the event of a prolonged bleaching period, the corals may eventually die.

How Can I Help When Corals Are Bleaching?

When corals are bleaching, there isn’t much we can do on a local level. However, there are certain things we can do to support our vulnerable reefs such as:

• Practice responsible snorkelling and diving to minimize damage to coral reefs

• Keep our environment clean by diposing of trash responsibly so they don’t end up in the ocean

• Corals are fragile animals. Don’t cause further stress to the corals by touching or breaking them

• Do not collect shells or corals, whether dead or alive