[Lewis Thomson (OP)]

Donald wants to know the answer to this question

"If the bleaching of parts of the great barrier reef was due to acidification and warming of the oceans, why did it recover so quickly and dramatically? Or was the diagnosis wrong, and another cause was overlooked? Or is bleaching not completely understood!"

Discuss in the comments below...

[evan_au]

Australia is badly affected in El Niño years, with higher-than average ocean temperatures.
- La Nina years are better, but there has been some bleaching even in recent La Niña years.

There is a project in Hawaii that tries to identify species of coral which are more heat-tolerant.
- They then multiply them rapidly by:
- Breaking them into little pieces (they grow faster when they are small)
- Planting them in an ocean farm (dangling on lines) until they are a decent size
- Then plant them out in the reef

Australia is also looking at options, but since the Great Barrier Reef extends for thousands of miles (or kilometers) in a north-south orientation, there is an additional option: sample corals living closer to the equator (which are presumably better heat-adapted), and plant them farther from the equator.