Australia’s Great Barrier Reef is experiencing an unprecedented second straight year of mass coral bleaching.

The 2,300-km reef suffered its most severe bleaching on record last year due to warming sea temperatures. This is the first time Great Barrier Reef bleached two years in sequence. We’ve seen heat stress build since December.

The back-to-back occurrence of widespread bleaching also meant there was insufficient time for corals to fully recover.

What is Coral bleaching?
Coral bleaching is the loss of endo-symbiotic algae from the coral, either through expulsion or loss of algal pigmentation turning them white.

Reasons for Coral bleaching
Bleaching occurs when abnormal environmental conditions, such as warmer sea temperatures, cause corals to expel tiny photosynthetic algae, draining them of their color.

How can Corals recover?
Corals can recover if the water temperature drops and the algae are able to recolonise them. But researchers said that coral reefs which survive rapid bleaching fuelled by global warming would remain deeply damaged with little prospect of full recovery.