1:00 pm - 2:00 pm
150 South Academic Building (SAB), University of Alberta, Edmonton AB
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Julia Orlova. This seminar is open to the general public to attend.
MSc with Dr. David Olefeldt.
Thesis Topic: Fifty Shades of Brown: Variability of Dissolved Organic Matter in Forested Streams across Spatial and Temporal Scales
Dissolved organic carbon (DOC) in stream water is critical for aquatic ecosystem functioning, but can be affected by climate change and land disturbance. To further our understanding of variations in and controls on stream DOC across spatial and temporal scales, I studied DOC concentration and composition over 2019-2021 using a combination of analytical techniques. At the regional scale, I assessed stream DOC across six forested ecozones in Canada, and discovered three dimensions of variation in DOC composition (aromaticity, oxygenation, biopolymer content) related to climatic and catchment parameters. At the regional scale, I focused on the Boreal Plains ecozone in Alberta, and observed seasonal and event patterns in DOC. Using laboratory incubations, I found that photodegradation was more important than biodegradation in shaping DOC composition. My results reveal variability in stream DOC at different scales and highlight the importance of temperature, lakes and wetlands as controls on DOC. The differences in DOC sources and in-stream processing have implications for carbon cycling and drinking water treatability.