Department of Land, Air and Water Resources, University of California, Davis, CA, USA.
Terra Analytics, Helena, MT, USA.
Science. 2018 Apr 6;360(6384):58-62. doi: 10.1126/science.aan4399.
Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth's land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet's nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth's nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink.
氮素供应是控制陆地碳固存和全球气候变化的关键因素。历史和现代观点都认为氮是从大气进入地球陆地生态系统的。在这里，我们证明了基岩是一种氮源，其与全球陆地环境主要领域的大气氮输入相媲美。从地球氮平衡、地球化学示踪剂和我们的空间风化模型中得出的证据表明，每年有 19 到 31 太克的氮从近地表岩石中释放出来。其中约 11 到 18 太克的氮在原地被化学风化，从而使未管理的（工业化前）陆地氮平衡增加了 8 到 26%。这些发现为协调地球氮预算提供了一个全球视角，对养分驱动的陆地碳汇控制具有重要意义。
