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: 1411942
• 负责人: Kathleen Treseder
• 金额: $ 39.82万
• 依托单位: University of California-Irvine
• 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 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1411942&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？跨越分子技术到全球规模建模。这项研究的动机是了解生物地球化学循环如何塑造综合地球系统，并在面对化石燃料二氧化碳排放量不断增加的情况下对气候变化的速度和程度产生关键影响。基岩岩性蕴藏着地球上 99% 的活性氮化合物（即除氮气以外的所有氮形式）；然而，这个巨大的氮库的生物地球化学重要性却被忽视了。教科书范式认为，新的氮仅通过生化固定或以沉积的形式从大气进入生态系统。然而，这些氮输入途径无法解释在许多陆地生态系统中观察到的高氮积累率，这构成了全球氮预算中的一个主要未知数。作为替代方案，主要研究人员认为，地质圈在陆地氮生物地球化学中发挥着重要作用？对陆地碳（C）循环和气候变化产生重大影响。他们提出研究来检验沉积岩是陆地生物圈广泛重要的氮源这一假设。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、流域、区域和全球尺度上研究基岩氮风化。所提出的最先进工具的组合（涉及实验室、现场和建模组件）是新颖的。分子尺度的研究重点是地球生物学； 它强调“食岩真菌”？ 使用受控实验室实验和跨现场的 NanoSIMS（纳米级二次离子质谱）来研究对氮风化反应的影响。土壤土壤、流域和区域分析将估计氮在一系列岩性、构造条件和气候中的物理和化学风化作用。 将通过测量天然氮稳定同位素以及碳、氮和磷化学，对风化速率与陆地氮循环之间的联系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，以衡量可用于储存全球陆地碳的岩石衍生氮的数量。