Spatiotemporal Variability and Uncertainty of Soil Respiration in the Conterminous United States
Elizabeth M Smith, University of Delaware, smithem@udel.edu (Presenter)
Rodrigo Vargas, University of Delaware, rvargas@udel.edu
Ben Bond-Lamberty, Pacific NW National Lab, bondlamberty@pnnl.gov
Ashley Ballantyne, University of Montana, ashley.ballantyne@umontana.edu
Kevin Arthur Endsley, University of Montana, arthur.endsley@ntsg.umt.edu
Zhi hua Liu, University of Montana, liuzh833@126.com
Kiazad Patel, Pacific NW National Lab, kaizad.patel@pnnl.gov
Bo Zhao, Institute of Geographic Sciences and Natural Resources Research, zhaobo@igsnrr.ac.cn
Soil respiration (Rs), the exchange of CO2 from the soils to the atmosphere, is driven by complex biogeochemical factors, such as soil biological activity, temperature, and soil moisture. Approximately 75-100 PgC yr-1 are released by soils, representing ~10% of total atmospheric carbon cycling through the soil. This 25 PgC range represents our lack of understanding Rs dynamics. Therefore, accurately upscaling Rs estimates at regional and global scales is a critical challenge that must be addressed. In this study we used digital soil mapping and machine learning techniques to estimate the spatiotemporal variability of Rs across the Conterminous United States (CONUS) from 2000-2020. The Soil Respiration Database was used to train a cubist regression tree model and Shapley values, a concept derived in game theory, were used to determine the contribution of each covariate. Finally, we found positive correlations between Rs and soil texture (sand, silt, clay) and soil organic carbon across National Ecological Network (NEON) regions. Our bottom-up approach estimates the annual Rs as 8.95±4.56 PgC yr-1, which is consistent with other bottom-up estimates of Rs for this region. The overall trend of Rs was not statistically significant across CONUS. These results support current estimates, further our understanding of spatiotemporal trends of Rs and highlights the knowledge gap in our understanding of the regional and global carbon budget.
Associated Project(s):
Poster Location ID: 3-26
Presentation Type: Poster
Session: Poster Session 3
Session Date: Thu (May 11) 3:00-5:00 PM
CCE Program: TE