Determining Mechanisms and Rates of Geologic Respiration at Watershed Scales

GSTDTAP

项目编号	1655506
	Determining Mechanisms and Rates of Geologic Respiration at Watershed Scales
	Julie Pett-Ridge
主持机构	Oregon State University
项目开始年	2017
	2017-09-01
项目结束日期	2019-08-31
资助机构	US-NSF
项目类别	Continuing grant
项目经费	136672(USD)
国家	美国
语种	英语
英文摘要	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.
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文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/71708
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Julie Pett-Ridge.Determining Mechanisms and Rates of Geologic Respiration at Watershed Scales.2017.