I have learned that: * coral reefs are made up mostly of calcium carbonate * coral reefs are mainly distributed in the tropical zone* The calcium carbonate will be decomposed in the reaction as follows: $$CaCO_3 + H_2CO_3 -> Ca^{2+} + 2HCO_3^-$$ Thus this reaction will be promoted in the environment with low pH. The ocean in the tropic zone should have lower acidity (higher pH) for the coral reef to exist.But in my opinion, the pH in the ocean is determined by the dissolution of CO2, and this process might be promoted in higher temperature?How to explain this issue?
The acidity of marine water is affected by the amount of dissolved carbon dioxide, which is absorbed from the air. Higher concentrations of carbon dioxide increase the acidity of the water.
