Abstract:

Wetlands, as a critical component of terrestrial ecosystems, play an indispensable role in maintaining global carbon balance and mitigating climate change. However, with the intensification of climate change and anthropogenic disturbances, wetland ecosystems are increasingly subject to degradation. In particular, vegetation loss leads to a substantial reduction in plant-derived carbon inputs, the carbon cycling pathways dominated by plant–heterotrophic microorganisms are disrupted, and the soil carbon sink capacity is significantly weakened. This review focuses on microbial metabolic responses and regulatory strategies under conditions of wetland degradation. We synthesize the ecological functions and carbon sequestration mechanisms of heterotrophic and autotrophic microorganisms, and highlight the metabolic plasticity—the capacity of microbes to flexibly adjust carbon utilization strategies and switch metabolic pathways which is a key adaptive strategy for sustaining carbon fixation under resource-limited conditions. We further explore the potential role of microbial metabolic plasticity in the early stages of wetland ecological restoration, particularly in facilitating the rapid accumulation of soil organic matter, re-establishing food web structures, and supporting ecosystem functional recovery. This work aims to advance our understanding of microbial regulation of soil carbon cycling in degraded wetlands and to provide a scientific basis for the restoration and functional reconstruction of these ecosystems.

Key words: degraded wetland, soil carbon cycle, microbial carbon fixation, metabolic plasticity, ecological restoration