Anthropogenic and Climate-Exacerbated Landscape Disturbances Converge to Alter Phosphorus Bioavailability in an Oligotrophic River

Cumulative effects of landscape disturbance in forested source water regions can alter the storage fine sediment and associated phosphorus riverbeds, shift nutrient dynamics degrade quality. Here, we examine longitudinal changes major element chemistry particulate (PP) fractions riverbed an oligotrophic river during environmentally sensitive low flow conditions. Study sites along 50 km Crowsnest River were located below tributary inflows from sub-watersheds represent a gradient increasing cumulative pressures across range land types (harvesting, wildfire, municipal wastewater discharges). Major elements (Si2O, Al2O3, Fe2O3, MnO, CaO, MgO, Na2O, K2O, Ti2O, V2O5, P2O5), loss on ignition (LOI), PP (NH4CI-RP, BD-RP, NaOH-RP, HCI-RP NaOH(85)-RP), absolute particle size evaluated for sediments collected 2016 2017. While total concentrations similar all sites, bioavailable (BD-RP, NaOH-RP) increased downstream with Al2O3 MnO levels disturbance. This study highlights quality impacts shows how convergence climate (wildfire) anthropogenic (sewage effluent, harvesting, agriculture) drivers produce legacy nutrients.