Microbial carbon dynamics in tropical forests: linking soil processes to atmospheric impacts under climate stress

Abstract

Tropical forests are key regulators of the global carbon cycle, yet their stability under climate change remains uncertain due to limited understanding of soil microbial contributions to carbon sequestration and greenhouse gas (GHG) emissions. Microbial communities drive organic matter decomposition, carbon stabilization, and GHG fluxes, making them central to carbon cycling in this ecosystem. This review synthesizes current knowledge on microbial carbon dynamics in tropical forest soils, focusing on how climate-induced stressors such as elevated CO₂, warming, and altered precipitation reshape microbial community composition, enzyme activity, and functional capacity. It examines feedbacks between microbial processes and atmospheric carbon, highlighting the dual role of microbes in both carbon sequestration and release. This review also addresses the quantification of microbial carbon pathways using isotopic tracing, soil organic matter fractionation, and molecular techniques to elucidate microbial assimilation, stabilization, and decomposition. Additionally, it explores innovative microbial strategies for carbon stabilization, including microbial engineering, biochar application, microbial-electrochemical systems, and mycorrhizal optimization, which enhance soil organic carbon retention and reduce CO₂ emissions. However, significant knowledge gaps remain, particularly in underrepresented tropical regions and in integrating microbial traits into Earth system models. To bridge these gaps, we propose a research agenda that necessitates long-term field studies, cross-ecosystem comparisons, and advanced molecular and biogeochemical tools to uncover microbial metabolic functions, necromass dynamics, and redox-mediated stabilization mechanisms under shifting tropical forest soil environments.