Biogeochemical Pathways of Carbon Biomineralization in Arboreal and Edaphic Systems

ABSTRACT Biomineralization processes in terrestrial ecosystems facilitate durable carbon dioxide removal (CDR) by transforming atmospheric CO 2 into stable inorganic phases through interconnected biogeochemical pathways. This review elucidates the oxalate–carbonate pathway (OCP), in which oxalogenic angiosperms biosynthesize calcium oxalate (CaC 2 O 4 ) crystals that are metabolized by rhizospheric oxalotrophs via oxalyl‐CoA decarboxylase ( oxc / frc )–mediated reactions, generating alkalinity and bicarbonate that support pedogenic CaCO 3 precipitation. Complementary mechanisms include microbially induced carbonate precipitation (MICP) via ureolysis ( ureC ), denitrification, sulfate reduction, and cyanobacterial photosynthetic CO 2 drawdown, which nucleate calcite polymorphs with extracellular carbonic anhydrase catalysis; phytolith‐occluded organic carbon (PhytOC) encapsulation within amorphous SiO 2 matrices exhibiting millennial‐scale recalcitrance; and enhanced rock weathering (ERW), which accelerates silicate (e.g., basalt) dissolution to release Ca 2+ and Mg 2+ for secondary carbonate formation. Empirical δ 13 C, radiocarbon, and clumped isotope (∆ 47 ) analyses from iroko and basaltic fig systems quantify sequestration rates of up to ~0.5–5 t CO 2 ha −1 year. −1 under specific field conditions, with estimated permanence potentially spanning 10 3 –10 6 years depending on mineral stability and environmental context. These estimates are derived from limited field and isotopic studies and should be interpreted as context‐dependent rather than broadly generalizable. Proposed monitoring, reporting, and verification (MRV) frameworks integrate mineralogical speciation, functional metagenomics, and biomarker analyses to assess additionality and mitigate risks. Translational strategies, including agroforestry, microbial augmentation, and ERW integration, provide co‐benefits for soil fertility and biodiversity, positioning biomineralization as a mechanistic link between biogenic carbon cycling and long‐term geological storage.