Water chemistry and periphyton biomass in the Rideau River: Have conditions changed after 24 years?

Over the past three decades, Rideau River (Ontario, Canada) watershed has experienced a land-use change from rural and agricultural land towards urban land, introduction expansion of invasive species. This study examined spatial temporal patterns periphyton biomass (chlorophyll-a ash-free dry mass) collected riffle zones in 1995 2019 along 66-km stretch River. also long-term changes water nutrient chloride concentrations through Provincial Water Quality Monitoring Network between 2000 2018. Declines total nitrogen 2018 occurred areas that have not urbanization since 2000s. In contrast, declines phosphorus increases at midstream downstream sites undergone during same time period. Conductivity showed an increase with distance similarly both 2019. Average Kjeldahl were lower compared to but did as seen many river systems, including River, earlier years. Periphyton length 2019, despite concentrations. These findings highlight persistence riverine multi-use experiencing ongoing anthropogenic changes.