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

The ratios of dissolved carbon, nitrogen, and phosphorus in rivers constrain downstream carbon and nutrient cycling, yet their long-term trends remain unclear. Using a 20-year ML-modeled dataset spanning 5084 catchments, we show that 27% exhibited coupled C-N-P trends with increasing or decreasing patterns, while 73% exhibited divergent trends. These divergent trends resulted in global declines in DOC-to-nutrient ratios, possibly linked to river warming, anthropogenic land-use expansion, and forest cover declines.