Proposing a potential strategy concerning Mineral-enhanced Biological Pump (MeBP) for improving Ocean Iron Fertilization (OIF)

Abstract

Ocean iron fertilization (OIF) is a geoengineering strategy aimed at mitigating global warming by reducing the amount of atmospheric CO2. However, the efficacy by which OIF vertically exports organic carbon of bloomed phytoplankton (mostly, diatoms) to the deep sea is low because of the remineralization of organic carbon during the sinking of diatomaceous silica (BSi). To address the low efficiency of the vertical C export of OIF, a potential strategy for enhancing oceanic biological pump using clay minerals, so-called mineral-enhanced biological pump (MeBP), is proposed herein. Under ideal operation of MeBP, the purposefully added clay minerals are supposed to agglomerate with BSi, facilitating an increase in the quantity of BSi settling and a decrease of organic carbon loss. Meanwhile, the structural Al of clay minerals would be assimilated by diatoms due to the biological dissolution of the clays, inhibiting the dissolution of BSi during its sinking. The abovementioned effects would significantly improve the efficiency of the vertical C export of OIF. The preliminary evidence and arguments in support of MeBP are presented.