Terrigenous dissolved organic matter (DOM) is continuously discharged by rivers into the
ocean, yet its distribution and reactivity within ocean basins remain poorly defined. With high
concentrations of terrestrial DOM in arctic rivers and a disproportionate share of global
riverine discharge on a volume basis to the Arctic Ocean, the influence of terrigenous DOM
on marine carbon budgets and the global carbon cycle can be significant. In this paper, we
report the detection of terrestrial DOM using optical properties of surface waters in the …