Abstract

Atmospheric deposition (AD) is a significant source of nutrient loading to waterbodies around the world. However, the sources and loading rates are poorly understood for major waterbodies and even less understood for local waterbodies. Utah Lake is a eutrophic lake located in central Utah, USA, and has high nutrient levels. Recent research has identified AD as significant sources for nutrient loading to the lake to better understand the dust AD sources, we sampled suspected source locations and collected deposition samples around the lake. We analyzed these samples using Inductively Coupled Plasma (ICP) for 25 metals to characterize their elemental fingerprints. We then compared the lake samples to the source samples to determine likely source locations. We computed spectral angle, coefficient of determination, multi-dimensional scaling, and radar-plots to characterize the similarity of the samples. We found that lake deposition samples were more similar to local sources than to distant sources. This suggests that the major source of atmospheric deposition onto Utah Lake is the local empty fields south and west of the lake and not the farther playa sources as previously suggested. Preliminary data suggest that dust AD is associated with dry, windy conditions and is episodic in nature. We show that AD from dust deposition is likely a small portion of the overall AD nutrient loading on Utah Lake, with the dry and precipitation source contributing the majority of the load.

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