River metabolism in the contiguous United States: Random forest model code, inputs and outputs

River metabolism is among the most uncertain fluxes in the global carbon cycle. We present estimates for gross primary productivity (GPP) and ecosystem respiration (ER) for over 175,000 rivers across the contiguous United States (CONUS), including metabolic responses to extreme hydrological conditions. Our model predicts annual GPP in CONUS rivers of 10.1 Tg-C yr -1 and ER of 18.7 Tg-C yr -1, implying that net ecosystem productivity (NEP = GPP – ER) is a small contributor to river CO2 emissions. More than 70% of river metabolism occurs in the west, where regions of both extreme heterotrophy and autotrophy exist. Autotrophy is prominent across the west and is sensitive to drought, particularly in understudied biomes like arid desert shrublands, which may indicate that global riverine uptake of CO2 is higher than hypothesized.