Fig 1.
Map shows interpolated 2015–2016 total phosphorus (TP) concentrations in Utah Lake sediments, the Wasatch Front urban area, wastewater treatment plants (WWTPs), tributaries, and the Jordan River outlet. Sample locations identified with circles and number label were sampled for surface water, pore water, and sediment (black circle = west and white circle = east) while sample locations identified with a cross were sampled for sediment only by Abu-Hmeidan et al. [21]. The urban area is defined according to the 2010 US census.
Fig 2.
P2O5 abundance versus LOI 550°C, CaO, and SiO2.
LOI 550°C is a measure of organic matter concentration. West samples (n = 13) were collected from sites 2–3, 5–10, and 14 and east samples (n = 13) were collected from sites 1, 4, 11–13, and 15.
Fig 3.
Backscattered SEM image of Utah Lake sediment.
The sample is overlain with energy dispersive spectroscopy dot maps of Ca (blue), Fe (green), and P (yellow). Image was taken for sediment sample 1-A collected from the middle of Provo Bay in October 2015.
Fig 4.
Sediment sequential extraction results.
Extraction results for 10 sediment samples collected during May—June 2016. Results are expressed as % total phosphorus NH4Cl = P in pore water and adsorbed loosely to surfaces, BD = redox-sensitive P mainly bound to oxidized Fe and Mn compounds, NaOH = P exchangeable against OH- ions or bound in organic matter, HCl = calcium phosphate minerals, and the residual is refractory organic P and nonextractable mineral P.
Fig 5.
Total dissolved phosphorus (TDP) concentrations in surface water (top) and pore water (bottom).
West samples (n = 13) were collected from sites 2–3, 5–10, and 14. East samples (n = 13) were collected from sites 1, 4, 11–13, and 15. For each sample type, TDP concentrations were averaged from the four sampling periods.
Fig 6.
The abundance of total cyanobacteria in Utah Lake during summer 2016 and 2017.
(A, E), Aphanizomenon flos-aquae (B, F), Dolichospermum flosaquae species (C, G), and Microcystis aeruginosa (D, H) cell counts for the summer of 2016 (n = 46) and 2017 (n = 52) across Utah Lake. Red circles and blue circles represent cell counts via semi-automated imaging flow cytometry from individual samples from the east and west side of the lake. Site labels correspond to locations shown in S2 Fig.