Feasibility of increasing marine carbon storage through olivine addition

As a result of the increasing consumption of fossil fuels all over the world, the ongoing global warming caused by rising atmospheric carbon dioxide (CO2) concentrations has attracted extensive attention. One of the theoreti-cally feasible and promising methods of reducing CO2 in the atmosphere is to sequester it by forming thermo-dynamically stable carbonates. Olivine, (Mg, Fe)(2)SiO4, is an abundant mineral that can react with CO2 to form carbonates when deliberately introduced into seawater. However, in addition to increasing the additional uptake of atmospheric CO2, it is inevitably accompanied by the release of other elements (e.g. Si, Ca, Mg, Fe and Ni) which could have adverse effects on marine organisms when those elements are at high levels. In this article, the reaction kinetics and mechanisms of olivine dissolution in seawater were introduced, the influencing factors on the olivine dissolution rate under ex situ conditions were highlighted, the possible impacts of the released products on marine organisms (mainly primary producers) and biogeochemical processes controlled by marine organisms were analyzed, and the potential applications to increase marine carbon storage were discussed. Furthermore, the current challenges of olivine application in seawater, such as dissolution reactivity, ecological effects, cost consumption, and future development directions (i.e. life cycle assessment technique and energy recycling approaches) have been highlighted to promote the practical applications of olivine dissolution in enhancing ocean alkalinity and increasing marine carbon sequestration.