SALTY-N · Salinity's secret climate impact: Does freshwater salinization enhance N2O greenhouse gas emissions?

The SALTY-N project aims to uncover how rising salinity levels in freshwater ecosystems influence nitrous oxide (N2O) emissions, a potent greenhouse gas contributing to global climate change. Freshwater salinization, driven by urbanization, agricultural runoff, and climate change, is expected to disrupt nitrogen cycling processes, specifically nitrification and denitrification, which are key sources of N2O. Current lake models do not adequately account represent N2O production and emissions and lack the potential to predict the impact of salinization on N2O production. SALTY-N will address this gap by developing an enhanced N reaction network module and integrating it into the widely used, open-source, CE-QUAL-W2 model. This model will be tested in two lakes, with distinguished sources of salinization—Lake Wilcox in Canada where increasing salinity is related to urbanization and use of the winter road salt, and Lake Lannenec in France that is subject to sea water intrusion—through field campaigns, laboratory experiments, and advanced biogeochemical simulations. The project will assess how salinity alters microbial N transformations and their contributions to N2O production, producing a transferable and opensource tool for researchers and water managers to predict the effects of freshwater salinization on N2O production. The findings will help inform future climate policies and environmental management strategies aimed at reducing greenhouse gas emissions from freshwater systems, directly addressing the priorities of the policy makers on climate change mitigation and ecosystem preservation.