Abstract

Internal sediment phosphorus (P) cycling may regulate harmful algal blooms (HABs) in shallow eutrophic lakes. Utah Lake frequently experiences HABs despite its high alkalinity and P-rich sediment. Phosphorus cycling between the lakebed and the water column is dependent upon stable P-sorption with organic matter (OM) and mineral species, which can vary with substrate availability, P-concentrations, temperature, redox, pH, and microbial activity. A full biogeochemical analysis of the water and sediment across seven sites shows Utah Lake to be spatially well-mixed in terms of composition and sorption, with few exceptions. Sediment P-concentrations (avg. 677 mg-P kg-1) primarily correlate with redox-sensitive iron (avg. 9403 mg-Fe kg-1) and manganese (avg. 295 mg-Mn kg-1) compounds (avg. 13.9%-Total P) and carbonate minerals (avg. 62.6%-Total P). Sorption experiments conducted with sediment from across Utah Lake reveal that as pH increases the favorability of P-sorption also increases, while the maximum number of available P-binding sites decreases. Kinetics experiments highlight nonlinear retention of P and demonstrate how sediments depleted of P generate faster retention rates and initiate early sorption during low aqueous P-concentrations. Ultimately, Utah Lake is a natural system existing in dynamic equilibrium; change one factor, and the lake will respond to maintain its state. Nevertheless, anthropogenic activities can still negatively impact the lake if left unchecked, as we have seen in the past.

Degree

MS

College and Department

Computational, Mathematical, and Physical Sciences; Geological Sciences

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2023-08-18

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd13337

Keywords

Utah Lake, Phosphorus, Cycling, Retention, Release, Binding, Sorption, Kinetics, Batch, Stirred-flow, Eutrophic, Linear, Freundlich, Langmuir, Sequential extraction, Sediment, Partitioning, HABs, Mineralogy, Carbonate, Redox, pH, Geochemistry, Sediment geochemistry

Language

english

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