Coral bleaching resources

Coral bleaching infographic

Corals are able to cope in a limited temperature range and when the temperature exceeds this limit, they experience heat stress.

Most corals have microscopic marine algae (called zooxanthellae) living inside their tissue — these give corals much of their colour and food.

When corals are under stress, this symbiotic relationship breaks down, and corals expel the zooxanthellae. 

Without zooxanthellae, the coral’s tissue becomes transparent and the coral’s bright white skeleton is revealed. 

If the stress is prolonged, bleached corals begin to starve without zooxanthellae and eventually die. 

The remaining coral skeletons are then colonised by algae, restricting the ability of baby corals (carried by currents) to establish themselves on these sites.

Coral bleaching health info graphic - healthy, bleached, dead coral covered in algae