https://e360.yale.edu/digest/great-barrier-reef-coral-cover-2022-record
In the northern and central stretches of the Great Barrier Reef, scientists have recorded the most extensive coral cover seen in 36 years of study, according to a new report from the Australian Institute of Marine Science (AIMS).
Researchers tracked hard coral across 87 reefs along the coast of Queensland from August 2021 to May 2022, finding that coral cover reached 36 percent in the northern third of the reef and 33 percent in the central third, up from 27 percent and 26 percent, respectively, the prior year…
In contrast to the upper stretches of the Great Barrier Reef, the southern third saw coral cover drop from 38 percent to 34 percent year on year. Scientists blamed the decline on an outbreak of crown-of-thorns starfish, which prey on corals.
Drawing on decades of field observations, the scientists modelled many possible future coral bleaching trajectories for Palauan reefs, each with a different simulated rate of thermal tolerance enhancement. They found that if coral thermal tolerance continues to rise throughout the 21st century at the most-likely historic rate, significant reductions in bleaching impacts are possible.
Corals create their own buffered environment which helps them survive over the millions of years.
Hankins studied two pieces of coral skeleton, one nearly 200 years old and one 115 years old, from the Great Barrier Reef and the Coral Sea located off the northeastern coast of Australia. Using Raman spectroscopy, she found that both corals were able to regulate their internal fluid chemistry to maintain growth of their skeleton, despite an ongoing increase in ocean acidity due to ocean acidification. The corals appeared to be able to sustain the production of calcium carbonate even as the chemistry of the surrounding seawater grew less hospitable.