OLIVINE WEATHERING REACTION
Weathering is the breakdown of rocks from contact with CO2, water, and organisms. When olivine interacts with ocean water and the CO2 dissolved in it, it undergoes a reaction that binds the carbon dioxide in bicarbonate, which is then used by animals, including corals, in their shells.
Those shells go on to settle in the sediment and eventually turn into limestone rock. Small and safe amounts of magnesium and silicate are left over from the reaction. The silicate is desperately needed by a crucial species of plankton known as diatoms, which themselves, further sink carbon.