Combined fate of rock-bound carbon in watersheds
Abstract
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.
In this study we examine the relationship between geologic respiration and physical erosion rates by studying watersheds with contrasting tectonic uplift, erosion, and sediment yields. Dissolved rhenium (Re) is tested as a tracer of geologic respiration. Rhenium is released during bedrock weathering and is thought to be conservatively delivered to surface water at the same rate as the release of CO2. This 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 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, organic carbon, and other geochemical tracers are 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. Together these analyses allow us to evaluate the role of uplift and erosion in controlling the fate of rock-bound organic carbon.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMEP51B..31G
- Keywords:
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- 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGEDE: 1625 Geomorphology and weathering;
- GLOBAL CHANGEDE: 1631 Land/atmosphere interactions;
- GLOBAL CHANGE