AGRIO

Most of the organic matter that enters the world’s freshwater systems is eventually mineralized into the greenhouse gases carbon dioxide (CO₂) or methane (CH₄) and subsequently released into the atmosphere. The rate of mineralization, the ratio between CO₂ and CH₄, as well as the production and emission of the potent greenhouse gas nitrous oxide (N₂O), all depend on environmental conditions. The ratio in which these gases are produced is crucial, as they differ significantly in their global warming potential; for CH₄ and N₂O they are 27 and almost 300 times higher, respectively, than CO₂.

Along the river-sea transition, the ecological conditions for the production and emission of GHGs vary greatly. In this project, we aim to study, measure, and model these conditions and their changes.

Understanding these impacts and the underlying mechanisms is essential for sustainable river management and the conservation of associated ecosystems. Balancing the needs of human development with environmental conservation is a complex challenge that requires careful consideration of ecological impacts and long-term sustainability. The overarching question of this proposal is how much net greenhouse gases are emitted along the river-ocean continuum, how the ratio of different greenhouse gases shifts along this gradient, and how water management strategies (such as continuous dredging, dams, groynes, the availability of natural floodplains, and nutrient emission reduction) impact this balance. With AGRIO, we aim to create the first comprehensive model for the entire Elbe-North Sea system, including sources and sinks for GHG emissions. This model will allow us to develop “what-if” scenarios to mitigate GHG emissions and to establish a robust approach to balancing anthropogenic demands on the river-sea continuum with the resulting greenhouse gas emissions.