Being a hobby aquarist and growing coral, I've been paying a lot of attention of the last 4-5 years to this.
First, life, uh, finds a way. Many corals reproduce / migrate by coming "unglued" from their skeletons and floating off to new homes, leaving "bleached" areas. They forgot to tell the world that for the last 5 years, coral was growing all around the reef in places it had never grown before- albeit in smaller quantity.
There's a big correlation between coral bleaching / death and Vibrio bacteria. These bacterial blooms come and go in cycles, but normally the coral fights off the infection and the bacteria dies out for lack of food. Most likely the infection took off because the coals were stressed- not necessarily from rising sea temperatures, but changes in salinity due to the typhoons.
Corals are quite resilient to temp change but are very intolerant to anything outside of 1.024-1.027 SG. It's estimated the typhoons may have dipped salinity to 1.019 in isolated patches for a few days at a time.
Mean sea temp on the GBR hasn't materially changed in 20 years. No correlation. Now that the chemistry is back to normal, the corals have reproduced and are back to their original locations... and we have our correlation. Salinity.
The typhoon salinity theory is pretty easy to accept. I've lost enough corals to say definitely: they don't like really salty water for long lol. Too low salt is also a huge concern. Temperatures
This is earth, where the climate changes. It ebbs and it flows. If we could just refrain from dumping tons of trash and chemicals into the oceans and soil, that would be good too. But even that the earth can handle.
Being a hobby aquarist and growing coral, I've been paying a lot of attention of the last 4-5 years to this.
First, life, uh, finds a way. Many corals reproduce / migrate by coming "unglued" from their skeletons and floating off to new homes, leaving "bleached" areas. They forgot to tell the world that for the last 5 years, coral was growing all around the reef in places it had never grown before- albeit in smaller quantity.
There's a big correlation between coral bleaching / death and Vibrio bacteria. These bacterial blooms come and go in cycles, but normally the coral fights off the infection and the bacteria dies out for lack of food. Most likely the infection took off because the coals were stressed- not necessarily from rising sea temperatures, but changes in salinity due to the typhoons.
Corals are quite resilient to temp change but are very intolerant to anything outside of 1.024-1.027 SG. It's estimated the typhoons may have dipped salinity to 1.019 in isolated patches for a few days at a time.
Mean sea temp on the GBR hasn't materially changed in 20 years. No correlation. Now that the chemistry is back to normal, the corals have reproduced and are back to their original locations... and we have our correlation. Salinity.
The typhoon salinity theory is pretty easy to accept. I've lost enough corals to say definitely: they don't like really salty water for long lol. Too low salt is also a huge concern. Temperatures
This is earth, where the climate changes. It ebbs and it flows. If we could just refrain from dumping tons of trash and chemicals into the oceans and soil, that would be good too. But even that the earth can handle.
https://www.gbrmpa.gov.au/news-room/latest-news/latest-news/corporate/2021/statement-long-term-monitoring-program-annual-summary-report