A global database of greenhouse gas fluxes from tropical inland waters

Strong consensus exists that inland waters emit globally significant quantities of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Tropical inland waters are often considered major contributors to these greenhouse gas fluxes, yet consistent and reliable estimates of aquatic greenhouse gas fluxes are lacking for the tropics. One of the limitations to obtaining a more accurate quantification of these fluxes is the lack of a curated and openly accessible data repository of greenhouse gas observations from across the tropics. To address this issue, we are developing the first comprehensive database of greenhouse gas concentrations and fluxes for tropical and subtropical inland waters (streams, rivers, lakes, reservoirs, wetlands). Our database includes over 15,000 records of gas concentration and flux measurements that were extracted from a total of 290 publications between 1975 and 2023. In this presentation we provide an overview of the database, summarise basic patterns of gas concentrations and fluxes across the region, and derive priority research areas for tropical inland water greenhouse gas research. We show that improved greenhouse gas emission estimates will require (1) addressing the observational gap in the mountainous and seasonal tropics, (2) developing approaches that cross boundaries between ecosystem types and scales, and (3) sharing and publishing data more systematically.