Montmorillonite as an “accelerator” for the microbial carbonpumpduring artificial biocrust construction

Abstract Background and Aims Artificial biocrusts play a crucial role as a carbon pool in reversing desertification. However, current research has focused predominantly on the microbes, neglecting the effect of clay minerals on the biocrust carbon pump. Methods This study constructed clay-based artificial biocrusts and investigated the effect of clay minerals on the dynamics of soil organic carbon (SOC) accumulation. The co-inoculation of montmorillonite (MMT) and Microcoleus vaginatus was carried out, and parameters related to SOC accumulation were determined, including microbial biomass carbon, the content of SOC, and chlorophyll a (Chl-a). Results The experimental results demonstrated that the SOC contents in the MMT-algae (≥ 1.4 g dm− 2) inoculation groups were over 3.45 times higher than those in the algae group on day 84, with 1.4 g dm− 2 as the optimal amount of MMT added. Furthermore, MMT played a crucial role in microbial growth and SOC stability, with microbial proliferation being the primary driver of SOC accumulation. Moreover, MMT favored microorganisms with strong photosynthetic capabilities. Conclusion MMT can serve as an accelerator for the microbial carbon pump during the construction of artificial biocrusts. This study provided a feasible solution and a reliable theoretical foundation for the accelerated restoration of desertification areas.