Open Collections

Lye, Sadie L. R.

University of British Columbia

Urbanization has disrupted the movement of freshwater and the materials it transports, altering the primary biogeochemical link between land and sea. Coastal ecosystems are subsidized by terrestrial organic matter and nutrient inputs; however, inputs have increased or been altered due to land-use change. Urbanization has increased impervious surfaces, changed vegetation abundance and composition, and introduced novel inputs via wastewater and stormwater. To investigate freshwater and stormwater organic matter and macronutrients (silicate, phosphate, and nitrate), I compared these constituents in Metro Vancouver river water and stormwater to literature values. I estimated the flux of these biogeochemical parameters transported to Burrard Inlet via stormwater annually and identified tracers of stormwater using stable isotopes (carbon and nitrogen) and fatty acids. The concentrations of these biogeochemical parameters were high and generally significantly different between river and stormwater samples. There were higher concentrations of nitrate and silicate in river samples and higher concentrations of phosphate, dissolved organic carbon, particulate organic carbon, and particulate nitrogen in stormwater samples. To investigate the composition of particulate organic matter (POM) in the surface water of Burrard Inlet, I used a Bayesian mixing model approach (MixSIAR) to quantify the relative contributions of phytoplankton, macrophyte, freshwater, and wastewater across 5 basins and 3 seasons. POM is a basal resource for marine food webs and a key component of zooplankton diet, which transfers energy to higher trophic level organisms. Thus, understanding how urbanization changes the composition of POM is important for understanding the productivity and functioning of marine ecosystems. Across all basins and seasons, phytoplankton contributed the most (average = 80 %), followed by macrophytes (average = 7.9 %), wastewater (average = 6.1 %), and freshwater (average = 5.8 %). There were seasonal and spatial differences in POM composition. As cities expand, so will their impact on coastal marine environments, and therefore, there is a need to understand how urbanization changes freshwater and the materials it transports, disrupting marine productivity and ecosystem functioning.

Text

2025-04-28

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/90873

Oceans and Fisheries

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/