Ryan, M. CathrynHe, JianxinTaube, Nadine Margot2019-09-302019-09-302019-09-27Taube, N. M. (2019). Understanding and linking anthropogenic and natural riverine disturbances to in-stream nutrient dynamics in an urbanized river reach (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/111099Substantial resources are spent annually to reduce phosphorus (P) and nitrogen (N) in entering rivers and to mitigate eutrophication. To achieve a more detailed understanding of the nutrient dynamics in a river reach, the nutrient interactions between different river compartments were examined. A focus of this study was the relationship between the aquatic biomass (macrophytes and epilithic algae) compartment and river flow (including extreme events) and wastewater treatment plant (WWTP) effluent loading. Aquatic biomass growth was strongly affected by both, river flow and WWTP effluent. The mixing process between the effluent and the river influenced the spatial distribution of biomass growth. Biomass recovery after disturbances proceeded relatively quickly but depended on the magnitude of the disturbance. WWTP effluent is a more continuous disturbance than flooding and the relationship is not as straightforward as with flow. Nutrient limitation differed for the different aquatic communities and varied in space and on seasonal and inter-annual time scales. A time lag between effluent loading reductions and macrophyte biomass decline suggested the occurrence of “legacy” sediment stores in the river reach. The other part of the thesis involved quantification of nutrient stores and export in the different river compartments to further examine their interactions. Surficial sediment stored more than 98% of nutrients over an m2 of river bed but surface water was the major driver in nutrient export out of the reach. WWTP effluent mass fluxes showed an impact on both N and P storage, so both nutrients should be considered for effluent quality management of aquatic biomass within the reach studied. Co-limitation of aquatic biomass and differing inter-compartment exchange reactions of the two nutrients further support the statement of considering both N and P in management decisions. Correlation analysis indicated that rivers compartments are intrinsically connected with respect to nutrient fluxes, suggesting that multiple nutrient compartments should be considered when establishing nutrient loading criteria and drawing conclusions about the nutrient limitation of biomass.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.nutrients, wastewater, CalgaryEcologyBiogeochemistryGeochemistryHydrologyEnvironmental Sciencesdoctoral thesis10.11575/PRISM/37160