Abstract
The sources of phosphorus (P) in Utah Lake can be diverse, including natural and anthropogenic point and non-point sources, such as atmospheric deposition, soil erosion, and industrial and urban wastewater effluents. This study collected interface sediments, column water, porewater, and sediment cores across this vast water body. These samples were then analyzed for their mineralogic, organic, and elemental composition to characterize the geochemical nature of water and sediment at the water-sediment interface within Utah Lake. The average concentrations of P and other elements found in the column water of an individual site do not significantly differ across depth suggesting Utah Lake to be well mixed vertically. Furthermore, most sites share similar water column P concentrations, excluding Provo Bay. Water column and pore water sampled with high spatial resolution reveal the redox potential shifts rapidly from oxidizing (+200mV) in the bottom water column to reducing (-100mV) in the porewater within 10 cm below the sediment surface. The influence of reducing conditions on oxidation state within the sediment is an important finding related to phosphate retention in the sediment of Utah Lake. The abundance of reducing conditions in the sediment, even at the shallow depths, suggests that redox sensitive minerals and metals (particularly Fe) are not a stable sink for phosphorus in the sediments. Averaging across all sites within the lake, excluding PB, the porewater conductivity decreased with increasing depth, with a defined shift at the water column-sediment porewater interface. The porewater pH was consistently less (6.5) than the lake water near the top of the water column (8.5). These findings will improve our fundamental understanding of geochemical cycling in shallow eutrophic lakes and be used to enhance the quality of water models that will be used to manage Utah Lake better.
Degree
MS
College and Department
Computational, Mathematical, and Physical Sciences; Geological Sciences
Rights
https://lib.byu.edu/about/copyright/
BYU ScholarsArchive Citation
Aremu, Abidemi Sherif, "Investigating the Geochemical Trends at the Sediment-Water Interface of the Shallow and Eutrophic Utah Lake" (2023). Theses and Dissertations. 10641.
https://scholarsarchive.byu.edu/etd/10641
Date Submitted
2023-12-18
Document Type
Thesis
Handle
http://hdl.lib.byu.edu/1877/etd13478
Keywords
phosphorous, Utah Lake, water quality, redox chemistry, porewater, sediment geochemistry
Language
english
