The Pulse of the Amazon: Fluxes of Dissolved Organic Carbon, Nutrients, and Ions From the World's Largest River

The Amazon River drains a diverse tropical landscape greater than 6 million km2, culminating in the world's largest export of freshwater and dissolved constituents to ocean. Here, we present organic carbon (DOC), inorganic nitrogen (DON, DIN), orthophosphate (PO43?), major trace ion concentrations fluxes from using 26 samples collected over three annual hydrographs. Concentrations were predominantly controlled by wet season flood pulse. Average DOC, DON, DIN, PO43? (±1 s.d.) 25.5 (±1.0), 1.14 (±0.05), 0.82 (±0.03), 0.063 (±0.003) Tg yr?1, respectively. Chromophoric matter absorption (at 350 nm) was strongly correlated with DOC concentrations, resulting flux 74.8 × 106 m?2 yr?1. DON positively discharge while nitrate + nitrite negatively correlated, suggesting mobilization dilution responses, Ammonium, PO43?, silica displayed chemostatic responses discharge. Major clockwise hysteresis (except for chloride, sodium, rubidium) exhibited either or responses. sources weathered cations also seasonality, highest proportion carbonate- silicate-derived occurring during peak baseflow, Finally, our seasonally resolved weathering model resulted an average CO2 consumption yield (3.55 ± 0.11) 105 mol km?2 These results represent updated temporally refined quantification that highlight strong seasonality river set robust baseline against which gauge future change.