Project Overview
Nitrogen is a vital plant nutrient, and its availability often limits tree growth. Denitrification is an anaerobic (no oxygen) microbial process that converts plant available nitrogen to nitrogen gases, including nitrous oxide, a potent greenhouse gas. Measurements of this process are complicated by both analytical challenges and tremendous spatiotemporal variation. As a result, estimates of denitrification are poorly constrained and Earth System Models often fail to capture the magnitude or global distribution of these nitrogen gas losses.
A series of grants from the National Science Foundation have funded research at Hubbard Brook to improve understanding of the environmental regulation of denitrification. The work has included long-term monitoring of nitrous oxide fluxes from soil to the atmosphere, field and laboratory measurements, and simulation modeling. The current grant addresses the effects of changes in temperature and precipitation on denitrification and is developing algorithms for use in an important global Earth System Model, the Community Land Model. The project is examining several factors hypothesized to regulate denitrification, including soil oxygen levels, soil depth, rainfall variability, soil warming, and soil acidification. New measurement approaches have been deployed, including soil core-based fluxes of nitrogen gases, continuous soil oxygen sensors, chamber-based gas fluxes, and stable isotopes. Together these measurements will provide a comprehensive assessment of denitrification and its environmental drivers, and will improve representation of denitrification in the Community Land Model. This work has important implications for policies regulating nitrogen as an air and water pollutant. Improvements to the Community Land Model support international science and policy programs for predicting future climate.
Principal Investigators
- Christine Goodale* (Cornell University)
- Peter Groffman (City University of New York)
- Jennifer Morse (Portland State University)
- Linda Pardo (USDA Forest Service)
- Cindy Nevison (University of Colorado)
* project contact
Graduate Students and Staff
- Anthony Stewart (Cornell University)
- Elizabeth Kreitinger (Cornell University)
- Catalina Mejia (Cornell University)
- Angelina Uribe (Portland State University)
- Whitney Denison (REU; Cornell University)
Nevison, CD, CL Goodale, PG Hess, WR Wieder, J Vira, PM Groffman. 2022a. Nitrification and denitrification in the Community Land Model compared to observations at Hubbard Brook Forest. Ecological Applications https://doi.org/10.1002/eap.2530
Nevison, CD, PG Hess, CL Goodale, Q Zhu. 2022b. Nitrification, denitrification, and competition for soil N: Evaluation of two earth system models against observations Ecological Applications https://doi.org/10.1002/eap.2528
Publications from earlier denitrification work at Hubbard Brook
Groffman, P. M., C. T. Discoll, J. Duran, J. L. Campbell, L. M. Christenson, T. J. Fahey, M. C. Fisk, C. Fuss, G. E. Likens, G. M. Lovett, L. Rustad, and P. Templer. 2018. Nitrogen oligotrophication in northern hardwood forests. Biogeochemistry 141:123-129.
Groffman, P. M., J. P. Hardy, M. C. Fisk, J. T. Fahey, and C. T. Driscoll. 2009. Climate variation and soil carbon and nitrogen cycling processes in a northern hardwood forest. Ecosystems 12:927-943.
Kanter, D. R., C. Wagner-Riddle, P. M. Groffman, E. A. Davidson, J. N. Galloway, J. D. Gourevitch, H. J. M. van Grinsven, B. Z. Houlton, B. L. Keeler, S. M. Ogle, H. Pearen, K. J. Rennert, M. Saifuddin, D. J. Sobota, and G. Wagner. 2021. Improving the social cost of nitrous oxide. Nature Climate Change 11:1008-1010.
Kulkarni, M., A. Burgin, P. M. Groffman, and J. Yavitt. 2014. Direct flux and 15N tracer methods for measuring denitrification in forest soils. Biogeochemistry 117:359-373.
Kulkarni, M. V., P. M. Groffman, and J. B. Yavitt. 2008. Solving the global nitrogen problem: it's a gas! Frontiers in Ecology and the Environment 6:199-206.
Kulkarni, M. V., P. M. Groffman, J. B. Yavitt, and C. L. Goodale. 2015. Complex controls of denitrification at ecosystem, landscape and regional scales in northern hardwood forests. Ecological Modelling 298:39-52.
Kulkarni, M. V., J. B. Yavitt, and P. M. Groffman. 2017. Rapid conversion of added nitrate to nitrous oxide and dinitrogen in northern forest soil. Geomicrobiology Journal 34:670-676.
Morse, J. L., J. Durán, F. Beall, E. Enanga, I. F. Creed, I. J. Fernandez, and P. M. Groffman. 2015a. Soil denitrification fluxes from three northeastern North American forests across a range of nitrogen depositon. Oecologia 177:17-27.
Morse, J. L., J. Durán, and P. M. Groffman. 2015b. Denitrification and greenhouse gas fluxes in a northern hardwood forest: the importance of snowmelt and implications for ecosystem N budgets Ecosystems 18:520-532.
Morse, J. L., S. F. Werner, C. P. Gillin, C. L. Goodale, S. W. Bailey, K. J. McGuire, and P. M. Groffman. 2014. Searching for biogeochemical hot spots in three dimensions: Soil C and N cycling in hydropedologic settings in a northern hardwood forest. Journal of Geophysical Research: Biogeosciences 119:1596-1607.
Weitzman, J. N., P. M. Groffman, J. L. Campbell, C. T. Driscoll, R. T. Fahey, T. J. Fahey, P. G. Schaberg, and L. E. Rustad. 2020. Ecosystem nitrogen response to a simulated ice storm in a northern hardwood forest. Ecosystems 23:1186-1205.
Werner, S. F., C. T. Driscoll, P. M. Groffman, and J. B. Yavitt. 2011. Landscape patterns of soil oxygen and atmospheric greenhouse gases in a northern hardwood forest landscape. Biogeosciences Discussions 8:10859-10893.
Wexler, S., C. L. Goodale, K. J. McGuire, S. W. Bailey, and P. M. Groffman. 2014. Isotopic signals of summer denitrification in a northern hardwood forested catchment. Proceedings of the National Academy of Sciences. 111:16413-16418.