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

合作研究：基岩氮和地球系统：从地球生物学机制到气候变化预测

• 批准号: 1411309
• 负责人: Bodo Bookhagen
• 金额: $ 40.61万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1411309&HistoricalAwards=false
• 关键词: Collaborative; Research; Bedrock; nitrogen; Earth

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.

该项目涉及控制基岩氮(N)风化速率的基础研究，涉及一系列陆地生态系统和条件。跨越分子技术到全球尺度建模。这项研究的动机是需要了解生物地球化学循环如何塑造整体地球系统，并且在面对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具有关键意义。基岩岩性包含地球上99%的活性N化合物（即除N2气体外的所有N形式）；然而，这个巨大的氮库的生物地球化学重要性被忽视了。教科书范式认为，新的氮仅通过生物化学固定或作为氮沉积从大气进入生态系统。然而，这些N输入途径无法解释在许多陆地生态系统中观测到的高N积累率，这是全球N收支中的一个主要未知因素。作为一种替代方案，主要研究人员认为，地圈在陆地氮生物地球化学中起着主要作用。对陆地碳(C)循环和气候变化产生重大影响。他们提出了一项研究来验证这样一种假设，即沉积岩是陆地生物圈氮的重要来源。研究团队包括地质学家、生物学家、土壤学家、生物地球化学家和地球系统科学家。他们将在分子、土壤土壤、流域、区域和全球尺度上研究基岩N的风化。建议的最先进的工具组合，包括实验室、现场和建模组件，是新颖的。分子尺度的研究主要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纳米二次离子质谱法（NanoSIMS，纳米级二次离子质谱法），对N风化反应的影响。土壤土盆、流域和区域分析将在一系列岩性、构造条件和气候中估计氮的物理和化学风化。风化速率与陆地氮循环之间的联系将通过测量天然氮稳定同位素和碳、氮、磷化学进行区域性实证研究。全球分析将强调一种新的建模方案，该方案将全球生物地球化学模型与风化模型相结合，以确定全球可用于储存陆地碳的岩石衍生氮的数量。