Large sediment methane production potential in reservoirs compared to lakes and rivers

Abstract Inland waters emit a globally significant amount of methane (CH 4 ) into the atmosphere. Measurements of potential CH 4 production rates in the sediment can help constrain the magnitude of CH 4 sources and time‐averaged emission rates. We explored the magnitude, variability, and drivers of potential CH 4 production rates in the sediment, based on compiled measurements (238 sediment cores from 72 aquatic systems) following a standardized laboratory incubation procedure. The data reveal > 4‐fold higher potential CH 4 production rates in reservoir sediments than lakes and > 14‐fold higher than rivers after being standardized for temperature. Sediment organic carbon content and depth below the sediment–water interface are universal drivers for potential CH 4 production rates across freshwater ecosystems. The disproportional high CH 4 production rate in sediments from human‐made water bodies calls for more comprehensive monitoring of their CH 4 emissions to inform carbon footprint and inventory efforts. This first meta‐analysis of potential CH 4 production rates in sediments from different types of freshwater aquatic systems may help with process‐based modeling of CH 4 emissions from individual water bodies in larger‐scale assessments.