Low Diffusive Methane Emissions From the Main Channel of a Large Amazonian Run-of-the-River Reservoir Attributed to High Methane Oxidation

The global development of hydropower dams has rapidly expanded over the last several decades and spread to historically non-impounded systems such as Amazon River’s main low land tributaries in Brazil. Despite recognized significance reservoirs methane (CH 4 ) emission, processes controlling this emission remain poorly understood, especially Tropical reservoirs. Here we evaluate CH dynamics channel downstream Santo Antônio hydroelectric reservoir, a large tropical run-of-the-river (ROR) reservoir Amazonia. This study is intended give snapshot during falling water season at initial stage after start operations. Our results show substantial higher production reservoirs’ littoral sediment than naturally flooded areas dam. or areas, high oxidation keep concentration fluxes low. Similar concentrations close dam suggest negligible degassing dam, but stable isotopic evidence indicates presence less oxidized pool ROR are designed disturb natural river flow traditional If enough mixing oxygenation throughout reservoir’s column, rates can also limit diffusive emissions from channel. Nevertheless, it important highlight that our focused on deep oxygenated High emissions, mainly through ebullition, may occur vast shallow represented by bays tributaries. However, detailed assessments still required understand impacts annual .