Methane process rates in lakes and reservoirs: a global analysis
Abstract
Collectively, lakes are an important source of the greenhouse gas methane (CH4). Previous efforts to synthesize CH4 measurements from lakes on a global scale have focused on CH4 emission measurements. However, to our knowledge, there have been no efforts to-date to synthesize global rates and controls of the two microbial processes that primarily control CH4 emission from lakes: (1) CH4 production and (2) CH4 oxidation. In this study, we use a meta-analysis approach to compare incubation-based measurements of CH4 production and oxidation rates from over 200 lakes around the world. In addition to rate measurements, we have also compiled information on methods, sampling design, and lake characteristics. We uncover a strong positive correlation between CH4 processing and trophic status, with higher rates of production and oxidation in eutrophic systems. Although gross rates of production and oxidation were positively correlated in systems where both were reported, oxidation efficiency decreased at high rates of gross production. Surprisingly, we did not find clear correlations between lake temperature, lake latitude, and CH4 processing rates. Taken together, our results suggest that the ongoing global trend of eutrophication in inland waters may be an important driver of higher CH4 emissions from lakes and reservoirs in the future.
About the Presenter
Sofia D'Ambrosio
Sofia D’Ambrosio is a Ph.D. candidate in the Environmental and Natural Resource Sciences program. As a member of the Global Change and Watershed Biogeochemistry research group, Sofia studies what factors influence the emission of methane, a potent greenhouse gas, from lakes & reservoirs. She combines fieldwork sampling from lakes in SW Washington with literature synthesis of methane data from hundreds of lakes globally to better understand freshwater greenhouse gas emissions. Her work helps improve quantification of methane emissions from lakes and reservoirs globally, as well as offer insight into how shifting climate and watershed management may influence future methane emissions.