Freed from a rocky embrace Nitrogen availability is a central controller of terrestrial plant growth and, thereby, of the carbon cycle and global climate change. It has been widely assumed that the atmosphere is the main source of terrestrial nitrogen input. Surprisingly, Houlton et al. now show that bedrock is just as large a nitrogen source across major sectors of the global terrestrial environment. They used three diverse and largely independent assessments of the nitrogen mobility and reactivity of rocks in the surface environment. These approaches yielded convergent estimates pointing to the equal importance of the atmosphere and bedrock as nitrogen sources. Science, this issue p. 58 Bedrock is as large a source of terrestrial nitrogen as the atmosphere. 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.

中文翻译：

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地球表面环境中广泛存在的岩石氮源的收敛证据

从岩石的怀抱中解放出来 氮的可用性是陆地植物生长的中央控制器，因此也是碳循环和全球气候变化的中央控制器。人们普遍认为大气是陆地氮输入的主要来源。令人惊讶的是，霍尔顿等人。现在表明，在全球陆地环境的主要部门中，基岩是同样重要的氮源。他们对地表环境中岩石的氮迁移率和反应性进行了三种不同且基本独立的评估。这些方法产生了趋同估计，指出大气和基岩与氮源同等重要。科学，这个问题 p。58 基岩是与大气一样大的陆地氮源。氮的可用性是控制陆地碳固存和全球气候变化的关键。历史和当代观点假设氮从大气进入地球的地表生态系统。在这里，我们证明了基岩是一种氮源，可与全球陆地环境主要部门的大气氮输入相媲美。从地球的氮平衡、地球化学代理和我们的空间风化模型中得出的证据表明，每年从近地表岩石中移动约 19 至 31 太克的氮。大约 11 至 18 太克的这种氮在原位进行化学风化，从而将未管理的（工业化前）陆地氮平衡从 8% 增加到 26%。这些发现提供了协调地球氮收支的全球视角，