沉积(地质)
土壤呼吸
环境化学
生态系统
环境科学
氮气
土壤水分
陆地生态系统
自养
异养
土壤碳
化学
农学
大气科学
生态学
土壤科学
生物
地质学
有机化学
沉积物
古生物学
遗传学
细菌
作者
Chen Chen,Han Y. H. Chen
标识
DOI:10.1016/j.scitotenv.2023.161986
摘要
Soil respiration (Rs) is a key indicator of belowground biological activities of terrestrial ecosystems. Despite ongoing atmospheric nitrogen (N) deposition due to anthropogenic activities, it remains uncertain how Rs responds to globally varied atmospheric N deposition. Based on a meta-analysis of 340 simulated experimental nitrogen addition studies, we aimed to identify the key factors altering the responses of Rs to N deposition and extrapolate these results to the global mapping of Rs changes under N deposition. We found the overall experimental N addition effect on Rs was insignificant, but the responses of Rs significantly shifted from positive to negative with increasing accumulated N addition amount and lower soil pH, and the negative responses to increasing N amounts were significantly intensified in acid soils. Also, the response of heterotrophic respiration to N addition significantly increased with a lower N amount, and both responses of heterotrophic and autotrophic respiration were significantly more negative in soils with lower pH. Our mapping efforts showed that global Rs overall increased by 2.8 % in response to the accumulated N deposition from 2000 to 2020. Regions with combined characteristics of high accumulated N deposition amounts and low soil pH, including Eastern U.S., Europe, and Eastern Asia, were hotspots of Rs declines under current and future atmospheric N deposition. Our findings challenge the long-held notion that N deposition has universal negative impacts on Rs, and suggest the spatial heterogeneity in the impacts of N deposition on belowground activities and carbon release across the globe.
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