Effects of total suspended solids on photomineralization of dissolved organic matter in the Peace-Athabasca Delta, Canada

Northern deltas receive chromophoric dissolved organic matter (CDOM) from their watersheds, which can be oxidized to carbon dioxide upon absorption of sunlight (i.e., photomineralized). These deltas also receive total suspended solids (TSS), which may shade sunlight absorption by CDOM, thus limiting photomineralization. To quantify this interaction for the first time, we measured photomineralization rates at 11sites in the Peace‐Athabasca Delta (PAD), Canada. We sampled waters during a July 2022 field campaign for TSS concentration, CDOM concentration (_^αCDOM,λ), total downwelling sunlight attenuation coefficients (K_d,_tot,_λ), and light attenuation coefficients due to CDOM (K_d,_CDOM,λ). TSS ranged from