Determining Mechanisms and Rates of Geologic Respiration at Watershed Scales

确定流域尺度地质呼吸的机制和速率

基本信息

批准号：
1655506
负责人：
Julie Pett-Ridge
金额：
$ 37万
依托单位：
Oregon State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1655506&HistoricalAwards=false
关键词：
Determining Mechanisms Rates Geologic Respiration

项目摘要

A vast pool of diffuse organic carbon is stored in rocks, constituting 30,000 times the amount of carbon stored in all organisms. During the breakdown of rocks and formation of soil, organic carbon stored in rocks is released as carbon dioxide into the atmosphere. Understanding the controls on this release of carbon is important for understanding the history of Earth's climate, and is also essential for evaluating how human impacts may be affecting this large reservoir of carbon. This proposed research project specifically investigates how mountain building and erosion control the release of organic carbon from rocks. The project will provide research experience and training for graduate and undergraduate students, including highly specialized techniques in organic and trace metal geochemistry. A new partnership will be developed between the US and international scientific communities studying the Earth's "critical zone" where rock, soil, water, air, and living organisms interact. The PIs will partner with two local programs to engage underrepresented groups at the middle and high school level through curriculum development for summer camp programs. These educational and outreach efforts will support and deepen existing relationships to promote increased participation of underrepresented groups in STEM fields. Ultimately this research will contribute to more accurate modeling of the global carbon and oxygen cycles, improving understanding of how the Earth has maintained habitability over geologic timescales and better constrain predictions of future change in atmospheric carbon dioxide.Mineralization of organic carbon in rocks, a process known as geologic respiration, is a major CO2 source to the atmosphere and thus a major control on Earth's climate over geologic timescales. The goal of this research project is to resolve a current paradox surrounding the relationship between erosion and geologic respiration. The relationship between geologic respiration and physical erosion rates will be characterized by studying watersheds with contrasting tectonic uplift, erosion, and sediment yields. Dissolved rhenium (Re) will be tested as a tracer of geologic respiration. Current understanding is that rhenium is released during bedrock weathering and conservatively delivered to surface water at a rate comparable to that of CO2 release. The utility of dissolved riverine Re as a quantitative tracer will be evaluated, and the importance of riverine particulate Re for accurate estimation of geologic respiration rates will also be verified. The proposed research includes a multi-scale analysis of geologic respiration from the weathering profile scale up through the watershed scale in well-constrained small mountainous river basins along the West Coast of the US. Laboratory analyses will include both soil and rock samples from weathering profiles and dissolved and particulate fractions of river samples collected across a wide range of flow conditions. Measurements of Re, 14C, biomarker analyses of organic carbon, and other geochemical tracers will be combined and analyzed in order to characterize the sources, flowpaths, and processes that deliver Re and rock-derived organic carbon from upland landscapes to rivers. While quantifying the rates and evaluating the key controls on geologic respiration in the target river basins, this research will also develop the understanding to make such determinations worldwide.

大量弥漫性有机碳存储在岩石中，构成了所有生物体中存储的碳量的30,000倍。在岩石崩溃和土壤形成过程中，岩石中存储的有机碳被释放为二氧化碳进入大气中。了解碳释放的控制对于理解地球气候的历史很重要，并且对于评估人类影响可能如何影响这种大型碳储层也是至关重要的。该提出的研究项目专门研究了山区建筑和侵蚀如何控制岩石中有机碳的释放。该项目将为研究生和本科生提供研究经验和培训，包括有机和痕量金属地球化学方面的高度专业技术。在研究地球“关键区”的美国和国际科学社区之间将建立新的伙伴关系，其中岩石，土壤，水，空气和生物体相互作用。 PIS将与两个本地计划合作，通过为夏季训练营计划开发课程开发在中学和高中阶段的代表性不足的团体。这些教育和推广工作将支持和加深现有的关系，以促进代表性不足群体在STEM领域的参与。最终，这项研究将有助于对全球碳和氧气循环进行更准确的建模，从而提高对地球如何保持地质时间尺度上的可居住性的理解，并更好地限制对二氧化二氧化碳二氧化碳未来变化的预测。岩石中有机碳的矿化过程，岩石中的有机碳，这是一个被称为地球口相关的岩石，因此是一个大事，因此是一个层次的氛围，因此是一个大气层的氛围。该研究项目的目的是解决围绕侵蚀与地质呼吸之间关系的当前悖论。地质呼吸与物理侵蚀率之间的关系将以对比构造隆起，侵蚀和沉积物产量进行对比的流域来表征。溶解的rhenium（RE）将作为地质呼吸的示踪剂进行测试。当前的理解是，在基岩风化期间释放rhenium，并以与CO2释放相当的速度保守地传递到地表水。将评估溶解的河流RE作为定量示踪剂的效用，并且还将验证河流颗粒物对准确估算地质呼吸率的重要性。拟议的研究包括对美国西海岸沿着良好约束的小山区河流盆地的流域量表的地质呼吸进行多尺度分析。实验室分析将包括来自风化曲线的土壤和岩石样品，以及在各种流动条件下收集的河流样品的溶解和颗粒分数。将对RE，14C，有机碳和其他地球化学示踪剂的生物标志物分析进行测量和分析，以表征从高地景观到河流提供RE和岩石衍生的有机碳的来源，流动路径和过程。在量化速率并评估目标河流地质呼吸的关键控制的同时，这项研究还将在全球范围内制定理解。