Collaborative Research: Bedrock nitrogen and the Earth system: From geobiolgical mechanisms to climate change forecasts

该项目涉及对一系列陆地生态系统和条件下基岩氮（N）风化速率控制的基础研究？从分子技术到全球范围的建模。这项研究的动机是需要了解地球化学循环如何塑造综合地球系统，并在化石燃料二氧化碳排放量上升的情况下对气候变化的速度和幅度产生关键影响。基岩岩性容纳了99%的所有反应性N化合物（即，除N2气体外的所有N形式）;然而，这一巨大的N储层的地球化学重要性却被忽视了。教科书的范例认为，新的N进入生态系统完全从大气中通过生化固定或作为N的沉积。然而，这些N输入途径是无法解释的高速率的N积累观察到的许多陆地生态系统，构成一个主要的未知数在全球N的预算。作为一种替代方案，主要研究人员认为，地圈起着重要的作用，在陆地氮地球化学？对陆地碳（C）循环和气候变化产生重大影响。他们建议进行研究来检验这一假设，即沉积岩是陆地生物圈中广泛重要的氮源。研究团队包括地质学家、生物学家、土壤学家、地球化学家和地球系统科学家。他们将在分子，土壤pedon，流域，区域和全球尺度上研究基岩N风化。所提出的最先进的工具，涉及实验室，现场和建模组件的组合，是新颖的。分子尺度的研究集中在地球生物学上，它强调？吃石头的真菌 利用受控实验室实验和NanoSIMS（纳米级二次离子质谱），在整个现场研究了对N风化反应的影响。土壤、流域和区域分析将评估氮在一系列岩性、构造条件和气候条件下的物理和化学风化作用。 风化率和陆地氮循环之间的联系将通过天然氮稳定同位素以及碳、氮和磷化学的测量进行区域性的实证研究。全球分析将强调一个新的建模方案，将全球地球化学模型与风化模型相结合，以确定可用于储存全球陆地碳的岩石来源氮的数量。

This project involves basic research of controls on nitrogen (N) weathering rates from bedrock across an array of terrestrial ecosystems and conditions ? spanning molecular techniques to global scale modeling. This study is motivated by the need to understand how biogeochemical cycles shape integrated Earth systems and has key implications for the pace and magnitude of climate change in the face of rising fossil fuel CO2 emissions. Bedrock lithologies house 99% of all reactive N compounds (i.e., all N forms other than N2 gas) on the planet; yet, the biogeochemical importance of this vast N reservoir has been overlooked. Textbook paradigms hold that new N enters ecosystems solely from the atmosphere via biochemical fixation or as N in deposition. However, these N input pathways are incapable of explaining the high rates of N accumulation observed for many terrestrial ecosystems, constituting a major unknown in the global N budget.As an alternative, the principal investigators suggest that the geosphere plays a major role in terrestrial N biogeochemistry ? imparting large effects on terrestrial carbon (C) cycling and climate change. They propose research to test the hypothesis that rocks of sedimentary origin represent a broadly significant source of N to the terrestrial biosphere. The research team includes geologists, biologists, pedologists, biogeochemists, and Earth system scientists. They will examine bedrock N weathering at molecular-, soil pedon-, watershed-, regional-, and global-scales. The proposed combination of state-of-the-art tools, involving lab, field, and modeling components, is novel. The molecular-scale research is focused on geobiology; it emphasizes ?rock-eating-fungi? effects on N weathering reactions, using controlled laboratory experiments and NanoSIMS (Nanometer-scale Secondary Ion Mass Spectrometry) across field sites. The soil pedon, watershed and regional analyses will estimate physical and chemical weathering of nitrogen across an array of lithologies, tectonic conditions, and climates. Linkages between weathering rates and the terrestrial nitrogen cycle will be empirically investigated regionally through measures of natural nitrogen stable isotopes, and carbon, nitrogen, and phosphorus chemistry. The global analyses will emphasize a new modeling scheme that couples a global biogeochemical model with a weathering model to scale the amount of rock-derived nitrogen that is available to store terrestrial carbon worldwide.