SYDNEY, Dec. 2 (Xinhua) -- Coral reefs have played a vital role in conducting the rhythm of Earth's carbon and climate cycles for more than 250 million years, a new study revealed.
Coral reefs have long been celebrated as biodiversity hotspots, but new research showed they have also played a much deeper role, said a media release of Australia's University of Sydney.
The study revealed that the rise and fall of shallow-water reef habitats have governed how quickly the planet recovered from major carbon dioxide shocks, it said.
Scientists from the University of Sydney and Universite Grenoble Alpes in France combined plate-tectonic reconstructions, global surface processes and climate simulations, with ecological modelling to reconstruct shallow-water carbonate production back to the Triassic Period.
They found that the Earth system flips between two distinct modes that determine the pace of climate recovery.
"Reefs didn't just respond to climate change -- they helped set the tempo of recovery," said study lead author Tristan Salles, associate professor from the University of Sydney's School of Geosciences.
When tropical shelves are extensive and reefs thrive, carbonate accumulates in shallow seas, reducing chemical exchange with the deep ocean and slowing the planet's recovery from carbon shocks, researchers said.
In contrast, when reef space collapses due to tectonic or sea-level change, calcium and alkalinity build up in the ocean, stimulating nannoplankton productivity and accelerating climate recovery, they said.
The findings recast reefs and other shallow-water carbonate systems as active modulators of Earth's buffering capacity rather than passive recorders of environmental change, said the study.
Salles said that the Earth system will eventually recover from the current massive carbon disruption, but this recovery will take thousands to hundreds of thousands of years, far beyond human timescales. Enditem
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