U.S. Department of EnergyOffice of Scientific and Technical Information
Bedrock weathering rates, reactive nitrogen influxes and effluxes, and nitrous oxide emissions rates from the Pumphouse Hillslope, East River Watershed, Colorado
Abstract
Atmospheric nitrous oxide contributes directly to global warming, yet models of the nitrogen cycle do not account for bedrock, the largest pool of terrestrial nitrogen, as a source of nitrous oxide. Although it is known that release rates of nitrogen from bedrock are large, there is an incomplete understanding of the connection between bedrock-hosted nitrogen and atmospheric nitrous oxide. Here, we quantify nitrogen fluxes and mass balances at a hillslope underlain by marine shale. We found that at this site bedrock weathering contributes 78% of the subsurface reactive nitrogen, while atmospheric sources (commonly regarded as the sole sources of reactive nitrogen in pristine environments) account for only the remaining 22%. About 56% of the total subsurface reactive nitrogen denitrifies, including 14% emitted as nitrous oxide. The remaining reactive nitrogen discharges in porewaters to a floodplain where additional denitrification likely occurs. We also found that the release of bedrock nitrogen occurs primarily within the zone of the seasonally fluctuating water table and suggest that the accumulation of nitrate in the vadoes zone, often attributed to fertilization and soil leaching, may also include contributions from weathered nitrogen-rich bedrock. Our hillslope study suggests that under oxygenated and moisture-rich conditions, weathering of deep, nitrogen-richmore »
- Contributors:
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- Lawrence Berkeley National Laboratory
- Rocky Mountain Biological Laboratory
- Publication Date:
- Other Number(s):
- paf_674
- Research Org.:
- Environmental System Science Data Infrastructure for a Virtual Ecosystem (ESS-DIVE) (United States); Watershed Function SFA
- Sponsoring Org.:
- U.S. DOE > Office of Science > Biological and Environmental Research (BER)
- Subject:
- 54 ENVIRONMENTAL SCIENCES
- Keywords:
- bedrock weathering; rock nitrogen; subsurface reactive nitrogen; nitrous oxide emissions; shale bedrock; watershed hillslope; Anion; Cation; Dissolved Ammonia; Mineralogy; Dissolved Inorganic Carbon; Dissolved Organic Carbon; Total Dissolved Nitrogen; Total Nitrogen; Total Organic Carbon; Groundwater Flux; Groundwater Level; Tensiometer Head; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > GROUND WATER > GROUNDWATER CHEMISTRY; EARTH SCIENCE > LAND SURFACE > SOILS > HYDRAULIC CONDUCTIVITY
- Geolocation:
- 39.034,-106.88|38.88,-106.88|38.88,-107.05|39.034,-107.05|39.034,-106.88
- OSTI Identifier:
- 1766328
- DOI:
- https://doi.org/10.15485/1766328
- Project Location:
-
Citation Formats
Wan, Jiamin, Tokunaga, Tetsu, Williams, Kenneth H., Brown, Wendy, Newman, Alexander M., Dong, Wenming, Bill, Markus, Beutler, Curtis A., Henderson, Amanda N., and Harvey-Costello, Nydra. Bedrock weathering rates, reactive nitrogen influxes and effluxes, and nitrous oxide emissions rates from the Pumphouse Hillslope, East River Watershed, Colorado. United States: N. p., 2021.
Web. doi:10.15485/1766328.
Wan, Jiamin, Tokunaga, Tetsu, Williams, Kenneth H., Brown, Wendy, Newman, Alexander M., Dong, Wenming, Bill, Markus, Beutler, Curtis A., Henderson, Amanda N., & Harvey-Costello, Nydra. Bedrock weathering rates, reactive nitrogen influxes and effluxes, and nitrous oxide emissions rates from the Pumphouse Hillslope, East River Watershed, Colorado. United States. doi:https://doi.org/10.15485/1766328
Wan, Jiamin, Tokunaga, Tetsu, Williams, Kenneth H., Brown, Wendy, Newman, Alexander M., Dong, Wenming, Bill, Markus, Beutler, Curtis A., Henderson, Amanda N., and Harvey-Costello, Nydra. 2021.
"Bedrock weathering rates, reactive nitrogen influxes and effluxes, and nitrous oxide emissions rates from the Pumphouse Hillslope, East River Watershed, Colorado". United States. doi:https://doi.org/10.15485/1766328. https://www.osti.gov/servlets/purl/1766328. Pub date:Fri Jan 01 00:00:00 EST 2021
@article{osti_1766328,
title = {Bedrock weathering rates, reactive nitrogen influxes and effluxes, and nitrous oxide emissions rates from the Pumphouse Hillslope, East River Watershed, Colorado},
author = {Wan, Jiamin and Tokunaga, Tetsu and Williams, Kenneth H. and Brown, Wendy and Newman, Alexander M. and Dong, Wenming and Bill, Markus and Beutler, Curtis A. and Henderson, Amanda N. and Harvey-Costello, Nydra},
abstractNote = {Atmospheric nitrous oxide contributes directly to global warming, yet models of the nitrogen cycle do not account for bedrock, the largest pool of terrestrial nitrogen, as a source of nitrous oxide. Although it is known that release rates of nitrogen from bedrock are large, there is an incomplete understanding of the connection between bedrock-hosted nitrogen and atmospheric nitrous oxide. Here, we quantify nitrogen fluxes and mass balances at a hillslope underlain by marine shale. We found that at this site bedrock weathering contributes 78% of the subsurface reactive nitrogen, while atmospheric sources (commonly regarded as the sole sources of reactive nitrogen in pristine environments) account for only the remaining 22%. About 56% of the total subsurface reactive nitrogen denitrifies, including 14% emitted as nitrous oxide. The remaining reactive nitrogen discharges in porewaters to a floodplain where additional denitrification likely occurs. We also found that the release of bedrock nitrogen occurs primarily within the zone of the seasonally fluctuating water table and suggest that the accumulation of nitrate in the vadoes zone, often attributed to fertilization and soil leaching, may also include contributions from weathered nitrogen-rich bedrock. Our hillslope study suggests that under oxygenated and moisture-rich conditions, weathering of deep, nitrogen-rich bedrock makes an important contribution to the nitrogen cycle. The data files are in Excel, which can be accessed using Microsoft Office, and consist of many data sets from the Pumphouse Hillslope PLM (Pumphouse Lower Montane) 1, 2, 3, and 4. They include soil to rock (0-10 meters) solid phase minerals and elements compositions; time- and depth-resolved pore-water chemistry and pore-gas compositions; time- and depth-resolved water table depths and water fluxes; subsurface weathering rates; nitrogen influxes and effluxes and mass balance. The attached paper is in a Word document, which can be accessed using Microsoft Office, and in pdf format.},
doi = {10.15485/1766328},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2021},
month = {Fri Jan 01 00:00:00 EST 2021}
}