Arctic Soil C and N Cycling Are Linked With Microbial Adaptations During Drought

作者：Theis Thomsen, Morten Dencker Schostag, Anders Priemé, Jonathan Donhauser · 发表于：Global Change Biology · 年份：2025 · DOI：10.1111/gcb.70502 · 被引用次数：3 · 研究领域：Microbial Community Ecology and Physiology、Soil Carbon and Nitrogen Dynamics、Polar Research and Ecology

ABSTRACT Climate change increases the frequency and intensity of drought events, yet the mechanisms of microbe‐mediated soil carbon (C) and nitrogen (N) cycling under drought are poorly understood. We conducted a microcosm experiment with a Greenlandic soil subjected to five levels of drought, reducing water content from 180% to 15% over the course of 3 weeks followed by rewetting, mimicking a natural drought event. We linked changes in microbial gene expression related to stress response as well as C and N cycling with greenhouse gas (GHG) emissions, extracellular enzyme activities, and soil C and N status. Maximum changes in gene expression occurred at intermediate levels of drought (80% water content), characterized by acclimation of microbial physiology to drought conditions, including production of osmolytes as well as cell wall and membrane modifications. This peak in gene expression changes marked a tipping point associated with a pronounced decline in microbial respiration as well as extracellular enzyme activities under more intense drought conditions. Interestingly, C‐cycling gene expression correlated with soil dissolved organic nitrogen (DON), NH 4 + , NO 3 − and PO 4 3− contents. Moreover, N‐cycling gene expression correlated with PO 4 3− contents and with the activity of laccases. These findings highlight linkages between microbial C, N, and P cycling because of stoichiometric constraints under drought. 24 h after rewetting, we found a shift in microbial express...