Soil ammonia-oxidizing archaea in alpine grasslands exhibit the highest temperature sensitivity in northern Chinese grasslands
摘要
MAT is the key factor influencing AOA communities in northern Chinese grasslands. MAT impacts AOA communities mainly through direct effects. AOA in alpine grassland soil exhibits the highest temperature sensitivity. AOA richness responds negatively to temperature exclusively in alpine grasslands.
Ammonia-oxidizing archaea (AOA) are key drivers of soil nitrification, but how they respond to climate warming across northern China’s diverse grassland types remains unclear. To address this, we analyzed 88 soil samples from 22 sites across three northern China grassland biomes based on metagenomic data, quantifying AOA temperature sensitivity as the regression slope of diversity indicators against mean annual temperature (MAT). Our results revealed MAT as the key factor influencing the relative abundance, richness, and composition of the potential AOA community. In alpine grassland, AOA communities exhibited the highest temperature sensitivity, with the steepest slopes of community composition and relative abundance, and a unique decrease in richness. This high sensitivity may reduce the AOA community diversity and destabilize nitrogen cycling in alpine grasslands. Structural equation modeling indicated that MAT impacted AOA communities via a direct route rather than indirect routes. These findings provide a scientific basis for assessing the potential risks of climate warming on grassland nitrogen cycling and informing early-warning and management strategies.