Ocean acidification impacts coral reef carbonate budgets through algae interactions

Recent research highlights the complex biological and chemical interactions affecting coral reefs under ocean acidification. One study indicates that rising CO2 levels favor the proliferation of low-profile turf algae. This competition can lead to the passive dissolution of coral skeletons, as the biological activity under the algae creates a local pH microenvironment that promotes chemical dissolution.

Conversely, another study focused on the southern Great Barrier Reef suggests that crustose coralline algae may provide a buffering effect. While these algae are vulnerable to acidification due to their high-magnesium calcite skeletons, their nighttime respiration promotes dissolution that increases alkalinity. This process helps maintain seawater supersaturation with respect to aragonite, potentially buffering shallow reef environments against extreme pH declines.