Ocean Acidification and Warming will Lower Coral Reef Resilience

In this study, the authors quantitatively analyzed how different combinations of CO2 and fishing pressure on herbivores will affect the ecological resilience of a benthic reef community consisting of three common groups: branching corals, fleshy macroalgae and turfs (free space for coral and algal colonization). Resilience was defined by the community’s capacity to maintain and recover to coral-dominated states. They developed a dynamic community model that was run for changes in sea surface temperature and water chemistry predicted by the rise in atmospheric CO2 projected from the IPCC’s fossil-fuel intensive scenario during this century. The findings demonstrate, using on the dynamics of a species pair of corals (Acropora) and fleshy macroalgae (Lobophora), that the effects of ocean acidification and warming on coral growth and mortality will have important impacts on coral reef resilience under increasing CO2. Specifically, by reducing coral growth (due to acidification) and survivorship (due to warming), increasing CO2 will lower the threshold value at which local and regional processes like herbivore overfishing and nutrification drive the study community from predominantly coral-dominated to predominantly algal-dominated states. Therefore, warming, acidification, overfishing and nutrification all drive the dynamics of the system in the same direction, suggesting that reduced coral resilience in a high-CO2 world is likely to be a consequence of both global threats and local-scale disturbances

Author: Anthony, K.R.N., J.A. Maynard, G. Diaz-Pulido, P.J. Mumby, P.A. Marshall, L. Cao, and O. Hoegh-Guldberg
Year: 2011
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Global Change Biology 17(5): 1798-1808. doi:10.1111/j.1365-2486.2010.02364.x

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