Diverging riverine dissolved C:N:P ratios under global environmental change

Dissolved organic carbon, total dissolved nitrogen, and total dissolved phosphorus (hereafter DOC, TDN, and TDP) are fundamental building blocks of aquatic life known to regulate key biogeochemical processes in riverine ecosystems 1 , 2 . This is because their ratios influence whether nutrients are immobilized in biomass or released and transported downstream, with important consequences for river ecosystem functioning 1 , 3 . For instance, shifts in riverine DOC:nutrient ratios can contribute to adverse downstream environmental effects, including eutrophication, deoxygenation, and increased greenhouse gas emissions from rivers 4 , 5 , 6 , 7 . Despite this importance, long-term global trends in riverine DOC:nutrient ratios remain poorly constrained due to a lack of empirical datasets that examine them simultaneously.