Abstract:
Soil microorganisms serve as the core driving force of the carbon (C) cycle in terrestrial ecosystems, and the necromass formed after their death constitutes a key component of the organic C pool in terrestrial ecosystems. A series of current climate change factors, such as frequent droughts and warming, may affect the transformation of microbial necromass C and its contribution to soil C pools. Based on this, this study systematically reviewed the response mechanisms and research progress of soil microbial necromass C accumulation to four key climate factors: temperature rise, drought, extreme precipitation, and low temperature. The results showed that climate change factors regulated the accumulation and decomposition processes of microbial necromass C mainly by affecting microbial metabolic activity, plant C source substrate supply, and microbial predator predation efficiency. Although the accumulation of microbial necromass C showed an increasing trend under high-temperature and low-temperature stresses, the comprehensive impact of these four stress factors on necromass C accumulation was still dominated by the adverse stress effect. By disturbing the composition and metabolic activities of the microbial community, the generation and transformation of necromass C were inhibited, ultimately leading to a reduction in its contribution to the soil organic C pool. This discussion on the response of soil microbial necromass C accumulation to climate change factors helps to deepen readers' understanding of the C cycle process mediated by soil microorganisms and the accumulation mechanism of their necromass C, and also to provide a relevant theoretical basis for predicting the dynamic evolution of the global C cycle in the future.