Spatial and Temporal Correlates of Greenhouse Gas Diffusion from a Hydropower Reservoir in the Southern United States

Water

Jennifer J. Mosher²  Allison M. Fortner²  Jana R. Phillips²  Mark S. Bevelhimer²  Arthur J. Stewart¹  Matthew J. Troia² 

[1] Xcel Engineering Inc., 1066 Commerce Park Drive, Oak Ridge, TN 37830-0117, USA; E-Mail:;Oak Ridge National Laboratory Environmental Sciences Division, P.O. Box 2008, Oak Ridge, TN 37831-6351, USA; E-Mails:

关键词: climate change;    CH₄;    CO₂;    hydropower;    random forests model;    reservoir;   

DOI  :  10.3390/w7115910

来源: mdpi

【 摘 要 】

Emissions of CO₂ and CH₄ from freshwater reservoirs constitute a globally significant source of atmospheric greenhouse gases (GHGs), but knowledge gaps remain with regard to spatiotemporal drivers of emissions. We document the spatial and seasonal variation in surface diffusion of CO₂ and CH₄ from Douglas Lake, a hydropower reservoir in Tennessee, USA. Monthly estimates across 13 reservoir sites from January to November 2010 indicated that surface diffusions ranged from 236 to 18,806 mg·m⁻²·day⁻¹ for CO₂ and 0 to 0.95 mg·m⁻²·day⁻¹ for CH₄. Next, we developed statistical models using spatial and physicochemical variables to predict surface diffusions of CO₂ and CH₄. Models explained 22.7% and 20.9% of the variation in CO₂ and CH₄ diffusions respectively, and identified pH, temperature, dissolved oxygen, and Julian day as the most informative predictors. These findings provide baseline estimates of GHG emissions from a reservoir in eastern temperate North America, a region for which estimates of reservoir GHGs emissions are limited. Our statistical models effectively characterized non-linear and threshold relationships between physicochemical predictors and GHG emissions. Further refinement of such modeling approaches will aid in predicting current GHG emissions from unsampled reservoirs and forecasting future GHG emissions.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.