Study: Coral Reefs Will Not Be Able To Rebuild Themselves In Face Of Warming, Acidification
A team of researchers led by Associate Professor Sophie Dove from the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland (Coral CoE at UQ) investigated the ability of coral reef ecosystems to retain deposits of calcium carbonate under current projections of warming and ocean acidification. Calcium carbonate is what skeletons are made of -- and it dissolves under hot, acidic conditions. Marine animals that need calcium carbonate for their skeletons or shells are called 'calcifiers'. Hard corals have skeletons, which is what gives reefs much of their three-dimensional (3D) structure. It's this structure that helps protect coasts -- and those living on the coasts -- from the brunt of waves, floods and storms. Without coral reefs the coasts 'drown'.
A/Prof Dove says the amount of calcium carbonate within a coral reef ecosystem depends on the biomass of hard corals. But it also depends on the combined impact of warming and acidification on previously deposited calcium carbonate frameworks. She says the results of the study indicate the rate of erosion will overtake the rate of accretion on the majority of present-day reefs.
"Today's Great Barrier Reef has a 30% calcifier cover," A/Prof Dove said. "If CO2 emissions aren't curbed, by the end-of-century a 50% calcifier cover is required to counter the physical erosion they face from storms and wave impacts," she said. "In addition, more than 110% calcifier cover is needed to keep up with the minimal levels of sea-level rise."
However, A/Prof Dove says both of these scenarios are unlikely because high amounts of hard corals perish with intense underwater heatwaves. Previous studies show marine heatwaves will become chronic in the warmer months of an average year under unmitigated CO2 emissions.
EDIT
https://www.sciencedaily.com/releases/2020/12/201203113226.htm
