Beaulieu, DelSontro & Downing - files for SI -Eutrophication drives the atmospheric impact of lakes and impoundments [CONFIDENTIAL - FOR REVIEW PURPOSES ONLY]

Data sets for article with the following abstract: Lakes and impoundments are important in the global carbon cycle, transporting, storing, processing and emitting significant amounts of carbon. Recent research shows that, from an atmospheric and climate change perspective, methane (CH₄) is the most important carbon emission from lakes and impoundments, constituting >70% of the climate impact. Further, a recent analysis shows aquatic productivity (i.e., eutrophication) is the most important driver of CH₄ emissions from lentic waters. Considering that aquatic productivity will greatly increase over the next century due to warming, increased runoff of production-limiting nutrients, and excess nutrients from augmented agricultural production and human sewage release, a concomitant increase in aquatic CH₄ emissions may occur. Here we analyze the future impacts of enhanced productivity on CH₄ emissions and show that, conservatively, inland water's productivity will increase by 50-300%, which in turn will drive up CH₄ emissions by 30-100 Tg of CH₄-C y^-1 (30-90%). This increased emission has a potential atmospheric CO₂ impact of 1.8-2.6 Pg C-CO₂eq yr^-1, which is equivalent to19-33% of the current effect of annual CO₂ emissions from burning fossil fuels. The net change in CH₄ emission over current conditions will have an effect equal to current estimates of CO₂ emissions resulting from land use change (e.g., conversion of forest into agricultural land) or 14-53% of oceanic carbon sequestration. Thus, it is not only important to limit eutrophication to preserve fragile water supplies, but also to avoid acceleration of climate change.