Date of Award
2024
Document Type
Open Access Dissertation
Degree Name
Doctor of Philosophy in Biological Sciences (PhD)
Administrative Home Department
Department of Biological Sciences
Advisor 1
Amy Marcarelli
Committee Member 1
Laura Brown
Committee Member 2
Jason Taylor
Committee Member 3
Trista Vick-Majors
Abstract
This dissertation applied novel modeling, experimental and statistical approaches to overcome the challenges of measuring and analyzing energy and nutrient cycling in streams through 3 studies: (1) determining the predictors of respiration and denitrification in streams across the United States, (2) simultaneous estimation of denitrification and nitrogen (N) fixation rates, and (3) the impact of C lability metrics on the interpretation of C degradation in DOM incubation experiments. In the first study, I used predictive modeling approaches to show that respiration and denitrification were positively correlated across the landscape but were predicted by factors at different spatial scales. Denitrification rates were best predicted by the characteristics of the stream, such as phosphorus and nitrogen concentrations and streambed cover type. In contrast, respiration was best predicted by characteristics of the landscape, such as watershed land cover and slope. In the second study, we applied a whole-stream modeling method to estimate denitrification and N fixation in streams, and then compared model estimates to denitrification and N fixation rates in natural streams. I also improved upon standard methods of air-water exchange rate estimation by using the natural abundance of argon as a tracer gas. In the final study, I determined that our understanding of bioavailability from dissolved organic matter incubation experiments may be impacted by the choice of C degradation calculation metric.
Creative Commons License
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Recommended Citation
Kelly, Michelle Catherine, "NOVEL ANALYTICAL APPROACHES FOR THE STUDY OF ENERGY AND NUTRIENT FLOW IN STREAMS", Open Access Dissertation, Michigan Technological University, 2024.