Under Gause's principle two species cannot indefinitely occupy the same niche. The north and south arms of Great Salt Lake are separated by a rail causeway, resulting in salinity differences and color variation between the arms. Farmington Bay is also separated from the south arm by a vehicular causeway to Antelope Island. These causeways allow examination of competitive exclusion of cyanobacteria in the hypersaline environment of the Great Salt Lake. Cyanobacterial distributions partially map salinity, with Aphanothece halophytica proliferating in the north arm, and Nodularia spumigena in the south arm. I hypothesized that cyanobacterial species abundant north of the railway causeway are competitively excluded from the south by other species, and that cyanobacterial species that thrive and bloom south of the Antelope Island causeway cannot grow in the high salinity of the north. To test these hypotheses, 129 flasks of autoclaved water from the north and south sides of each causeway were inoculated with Great Salt Lake water samples from the north and south sides of the causeways. Four genera of cyanobacteria, Aphanothece, Oscillatoria, Phormidium, and Nodularia were identified and counted from the culture flasks using comparative differential interference contrast, fluorescence, and scanning electron microscopy. Counts of the cyanobacteria found in each flask were totaled and two way Analysis of Variance tests as well as exact tests were performed. Rankings of median abundances were also calculated. These data support the first hypothesis because Aphanothece halophytica was found in all inocula, but appears to be suppressed by the presence of Nodularia spumigena, which periodically blooms. The second hypothesis is also supported by the data because N. spumigena was found only in inocula from the less saline waters south of Antelope Island causeway, and apparently cannot survive the high saline waters north of the railway causeway.

Ooids of Great Salt Lake, Utah (GSL) have been studied periodically by geologists since the 1960's. These studies have documented the locations of ooid deposits, bulk composition, mineralogy, and internal structural variations of GSL ooids. Ooids have also been identified in sediment cores from lakes predating the Great Salt Lake, but similar descriptions have not been made for these ooids. Samples of ooids from cores in Pilot Valley, UT/NV and Knolls, UT have been obtained, along with samples from the Great Salt Lake at Bridger Bay and Rozel Point. The cortical fabrics and crystal morphologies of these ooids were studied in thin section and under scanning electron microscopy. Examples of cortex morphologies previously documented in GSL ooids were observed, to some degree, in ooids from Pilot Valley and Knolls. Knolls ooids had unique cortical layers that were resistive to acid and appeared to be dominantly comprised of clays. Bulk dissolution ages were obtained for ooids from each location. Ooids form both Pilot Valley and Knolls had average ages that pre-date Lake Bonneville, whereas GSL ooids from Bridger Bay had an average age of roughly 3,500 years before present (yr BP) and Rozel Point ooids had an average age of 500 yr BP. Along with a bulk age, ooids from Bridger Bay at the Great Salt Lake were subjected to serial dissolutions during which a split of gas was taken from each stage and an age was obtained. Ages spanned 7,000 years with the final dissolution stage delivering an average age of 9,000 yr BP. Based on this data it is likely that GSL ooids at Bridger Bay have been forming since the cessation of Lake Bonneville and that many of the nuclei in Bridger Bay ooids are remnant peloids from the Gilbert level of Lake Bonneville.

Non-native invasive plant species can often have negative effects on native ecosystems, such as altered nutrient cycling, decreased habitat for wildlife, and outcompeting native plants. Around the Great Salt Lake (GSL), Utah, the invasive wetland grass Phragmites australis has become abundant in wetlands around the lake. Phragmites is replacing many native wetland plants provide important waterfowl habitat around the GSL. For successful management of Phragmites in GSL wetlands, it is important to know the current distribution of Phragmites, as well as areas that might be vulnerable to future invasion by Phragmites. To do this, we used multispectral aerial imagery to map the current distribution of Phragmites. We then created a model that statistically related the Phragmites distribution data to a suite of environmental predictor variables such as salinity, proximity to nutrient sources, or proximity to roads. Results from our model suggest that Phragmites is more likely to be found in wetland areas close to point sources of pollution, with lower elevations with prolonged inundation, and with moderate salinities. We used these results to identify areas around GSL that might be vulnerable to future invasion. Results from our study will assist wetlands managers in prioritizing areas for Phragmites monitoring and control by closely monitoring areas of prime Phragmites habitat.

This study was conducted to determine basic data on the incidence of lead shot in ducks us ing the Great Salt Le.lee Basin. The study has been divided into two parts; (1) incidence of ducks carrying lead shot in their tissues and (2) incidenoe of ducks carrying ingested lead shot.

Drawing from literature on place, this dissertation studies place dynamics in relationships between people and a mixed amenity place. Using Great Salt Lake (GSL), Utah, as a case study, I use a social constructionist approach to examine the sense of place held by those who live nearest to the lake. I analyze qualitative interview and focus group data as well as quantitative survey data to discern the meanings the lake holds for these nearest neighbors and to examine distinctions between people who see the lake differently. This study is relatively unique in its examination of relationships with a mixed amenity place, as prior place research has focused on high amenity places such as resort locations. A number of distinctions were found. Place attachment to GSL was less widespread than seen with high amenity places, and there were some residents for whom the lake held negative meanings. The lake held multiple meanings for many research participants, including combinations that appeared incongruous in mixing both positive and negative lake images. Some participants appeared to have no sense of the lake. Additionally, there was evidence of social stigma related to living near the lake. This study can help natural resource managers, community leaders and policy makers to better understand the relationships between local residents and GSL, which prior place research has shown to be a useful indicator of environmental concern, commitment to the place, and support for resource management. There were many things residents did not appear to know about the lake, including, for example, the natural workings of the lake ecosystem, the effect built features have had on this ecosystem, and the economic contributions to local communities, counties and the state from lake-related enterprises. Also of interest, these nearest neighbors talked about how changes related to the lake have affected them. This study provides justification for further work on people-place dynamics with mixed amenity places, as it revealed dynamics not be seen in research on higher amenity settings. The study also demonstrates the need for continued social science research on GSL, to provide further understanding of people's relationships with this important place.

I studied nutrient reserves, digestive organs, molt intensity, diets , and seasonal changes in food resources available to postbreeding adult male Northern Pintails (Anas acuta) and Cinnamon Teal (Anas cyanoptera) in marshes near Great Salt Lake, Utah. Total lipid and protein reserves of Northern Pintails were lower during the flightless period than before or after. For Cinnamon Teal, total protein was lowest during the flightless period, and total lipid showed a similar trend. Total mineral did not differ among plumage classes in either species. Use of nutrient reserves in these species may be an endogenous rhythm in response to increased predation risk or unpredictable food resources while flightless. Digestive organ metrics of Northern Pintails generally were lower while flightless than before or after, apparently due to decreased dietary consumption. Cinnamon Teal digestive organ metrics changed little from preflightless to flightless stages, but generally increased while postflightless. Changes in Cinnamon Teal digestive organs may be related to increased dietary intake or increased dietary fiber consumption. Total molt intensity in these species was generally high before and during wing molt, and decreased during the postflightless period. Mathematically weighting total molt scores produced results similar to those obtained without weighting, but selection of body/feather regions is critical to obtaining unbiased estimates. Changes in relative availability of plant and animal foods during July and August were marked . Animal foods made up 96% of total foods measured in the study area during early July, but plant foods comprised 95% of available foods by late August. Changes in abundances of food resources are probably an important determinant of diet selection in postbreeding adult ducks and ducklings in marshes near Great Salt Lake. Diets of postbreeding adult male Northern Pintails and Cinnamon Teal did not differ between species, but did among flight classes. Changes in use of food items and in use of animal and plant foods were consistent with changes in relative abundances of food resources. Postbreeding adult males of these species apparently foraged opportunistically.

Windblown dust events can be defined as windblown dust emitted from the Earth's surface to the atmosphere. These events have significant impact on local air quality. Predicting the location and magnitude of these events is vital for Utah air quality assessment and planning. Previous modeling studies have focused only on past dust events. This work utilized a state-of-the-science software framework based on the Community Multiscale Air Quality (CMAQ) v5.3.1 modeling system to predict dust events in Utah. The framework was verified using previous studies for dust events in April 2017 and March 2010. Once verified, the framework was used to predict the impact of future land use properties on dust events. Two scenarios were studied – shrinking of the Great Salt Lake and the addition of large-scale solar farms west of the Wasatch Front. Both showed increases in dust concentrations overpopulated areas using the meteorological conditions from the April 2017 dust event. Such information from future impact studies can assess potential impacts from climate change and can guide government water and land use policies to mitigate dust event impacts.

The fluid circulation patterns, temperature distributions, and density gradients of the South Arm of the Great Salt Lake were modeled using the Estuary, Lake, and Coastal Ocean Model (ELCOM) from the Centre for Water Research at the University of Western Australia. The effort is part of a research study in conjunction with the United States Geological Survey (USGS) and the Utah Water Research Lab located at Utah State University. The model was simulated for several different cases of salinity gradients over different time periods, using temperature and wind data from 2006. The model is then used to identify factors which may provide a transport mechanism of heavy metals such as selenium and mercury from the sediment layers to the upper brine layers where it is introduced into the food chain.

The purpose of this paper is to report findings concerning the effects of cadmium , copper, and mercury on the brine shrimp Artemia Salina, of the Great Salt Lake. Metal toxicity was observed in relation to acute susceptibility, growth, reproduction, and hatching of the brine shrimp. Heavy metal concentrations such as cadmium, copper, and mercury are known to be considerably higher in the Great Salt Lake than those in both freshwater and seawater. No published study has been concerned with heavy metal effects on organisms in salinities greater than seawater (35 grams per liter total dissolved solids). The experiments reported in this paper were carried out in salinities approximating the Great Salt Lake (150-320 grams per liter total dissolved solids). Results of this study indicate that cadmium, copper, and mercury toxicities to the brine shrimp may not be comparable at varying salinities. Findings of acute toxicity experiments were compared to other heavy metal studies on marine organisms. The brine shrimp was found to be very resistant to cadmium and copper poisoning and moderately resistant to mercury. Neither cadmium nor copper inhibited hatching of the brine shrimp eggs although mercury caused severe inhibition at concentrations of 0.3 milligrams per liter. Only cadmium at concentrations between 1.0 and 33 milligrams per liter significantly suppressed growth rate and reproduction. Mercury and copper were not found to affect growth and reproduction below concentrations causing acute poisoning. Mercury was found to be the most lethal to the adult brine shrimp with a range of times to 50 percent mortality from 126 to 8.5 hours at mercury concentrations of 0.01 to 100 milligrams per liter respectively. Copper caused mortalities at concentrations of 1 to 67 milligrams per liter with respective times to 50 percent mortality of 124 and 12 hours. Copper was shown to precipitate out at concentrations near 12 milligrams per liter, Cadmium was found to be the least lethal with a range of times to 50 percent mortality from 94 to 320 hours with respective cadmium concentrations of 100 and 3.3 milligrams per liter.

Thirteen bacterial cultures were isolated from the North arm of Great Salt Lake during the months of January and February of 1973. Eleven isolates were gram-negative pleomorphic rods which lysed in hypotonic solution. The remaining two were gram-positive cocci. All isolates and one known strain of Halobacterium salinarium were subjected to examination of morphological, cultural, physiological, and biochemical characteristics. A numerical taxonomic analysis was applied to the compiled characters to compute a coefficient of similarity for each individual isolate as compared to all other isolates. A comparative analysis was included in the similarity computation using characters assembled from those reported in the literature for six taxonomically accepted species of halophilic bacteria. The lake isolates proved to be extreme halophiles with relative high levels of similarity between each other and the known bacteria included in the numerical analysis.