Thesis (M.A. 1936)--Dept. of Bacteriology, University of Utah. / Bibliography: l. 98-101.

Dormancy is a plausible strategy for bacteria to overcome the effects of temporal fluctuations in resources or stresses and await more “optimal” conditions to resume metabolic activity and growth. Seasonal changes in environmental conditions force microbes to adjust their metabolic activity accordingly, and community composition drastically shifts. In extreme environments, however, the overriding effects of a constant stress may constrain the need or benefit of bacteria entering dormancy. In hypersaline lakes, high metabolic activity is required to maintain adaptations that permit survival. Sampling from six lakes on a salinity gradient (0.05% – 30.3%), we measured seasonal fluctuations in bacterial dormancy patterns in summer, fall, winter, and spring of 2013-14. Dormancy was calculated based on ratios of OTU recovery between 16S rRNA-based communities (only the active bacteria) and 16S rRNA gene-based communities (all bacteria present in the community) from lake water. Dormancy was linked to lake chemistry shifts through time. We found that salinity was strongly related to relative bacterial dormancy. There was a negative linear relationship (R2 = .89 P <0.01) between total dormancy and salinity. Total phosphorus (R2 = .63, P < .001) and relative community contribution by rare taxa (R2 = .89, P < .001) were also important in structuring dormancy. Our findings suggest that temporal nutrient flux is highly influential on bacterial community composition and activity, but that the presence of an extreme variable decreases change in both through time.

The study of organisms from extreme environments is an emerging field of research with applications to multiple scientific areas. One of these extreme environments is Great Salt Lake (GSL), whose microbiology has yet to be extensively studied. This dynamic and unique environment offers an excellent opportunity to increase understanding of hypersaline ecology. Cultivation of microorganisms remains an important part of ecology research, as it is essential for understanding microbial physiology. We report here the culturing and characterization of isolates from Rozel Point, located on the northeastern shore of Great Salt Lake. This site was chosen because of the presence of petroleum seeps at Rozel Point and the extreme salinity of the North Arm of GSL. We hypothesize that culturing at GSL will reveal a diverse prokaryotic population, with both commonly isolated and novel organisms. We would predict that prokaryotes at GSL will share many features in common with other hypersaline microbial communities, but that given the distinctive properties of the site, there will be unique characteristics as well. Samples were taken from Rozel Point and cultured using direct plating, enrichment cultures, and dilution cultures with a variety of minimal and complex halophilic media. Fluorescence in situ hybridization (FISH) was used to examine abundance of cultured organisms in the environment. Culturing and characterization has revealed both isolates novel and previously uncultured, with many unique characteristics. FISH demonstrated that, unlike most environments, in GSL the dominant species are culturable. These results show the value of culturing in discovering new organisms and demonstrating diversity at the microbial level. Culturing of these organisms will allow for further research to be done on microbial processes that occur in this system and the unique properties of halophilic microbes.

No description available.

xiii, 248 p. : ill. A print copy of this title is available through the UO Libraries under the call number: KNIGHT E98.P8 D43 1992 / The current interpretation of post-Archaic culture history in the northeastern Great Basin is that the Great Salt Lake regional variant of the Fremont culture arose from an Archaic base and is distinguished by two types of unpainted pottery, Great Salt Lake Gray and Promontory Gray. Seen as ethnically unrelated to the Fremont, the subsequent Shoshoni culture is marked by one type of unpainted pottery, Shoshoni Ware. These types are said to be characterized by distinct combinations of attributes, but close examination reveals that what these combinations are, and how they distinguish each type, has not been clearly described in the archeological literature. In this study, I re-analyze fragments of undecorated pottery previously classified as Great Salt Lake Gray, Promontory Gray, and Shoshoni Ware. Through rigorous and replicable methods, five major attributes found in every sherd are examined: wall thickness, exterior surface color, temper material, temper size, and technique of vessel shaping. This analysis showed that previous identifications of pottery attributes were partially or entirely erroneous. Every attribute measured demonstrated the same essential pattern: Great Salt Lake Gray had a wide range of variation, and Promontory Gray and Shoshoni Ware fell within this range. Further, except for one form of temper material, Promontory Gray and Shoshoni Ware shared the same attributes with one another. Ethnographic evidence is also presented that links late prehistoric pottery to that of the historic Shoshoni, confirming a single unbroken pottery tradition in the Great Salt Lake region. I conclude that the evidence of this study does not support the concept of two unrelated pottery traditions (Fremont and Shoshoni) in the Great Salt Lake region. Based on this work, much of the traditionally conceived post-Archaic culture history of this region must be reevaluated.

The development of a model capable of predicting the long term (seasonal) distribution of water quality constituents within Great Salt Lake was undertaken as a portion of the ongoing Great Salt Lake project at Utah State University. The overall goal of the project is the development of a modeling framework to assist the relevant decision making bodies in the comprehensive management of the Great Salt Lake system. Phase I of the project provided the overall structural framework for management of the Great Salt Lake system, identified data needs, and established priorities for the development of submodels for incorporation into the overall framework. Phase II of the project involves the process of developing submodels, and Phase III will be concerned with application of the framework of models to specific management problems. This study provides, as part of the second phase of the Great Salt Lake project, a model capable of predicting the long term distribution of quality constituents within the lake. This capability is a necessary component of the modeling framework since it will allow the investigation of the effects which alternative water quality management plans will have on the distribution of water quality constituents within the lake. The water quality model of the lake is based on the application of the advection-diffusion equation to the three-dimensional transport of a quality constituent. The modeling technique is formulated by discretizing the system as a network of nodes interconnected by channels in both the horizontal and vertical directions. This representation of the system allowed the horizontal transport to be treated mathematically as one-dimensional. The resulting modeling technique is applicable to any lake, estuary, or bay in which the concentration gradients must be described in all three coordinate directions. In applying the model to Great Salt Lake a two-layered vertical network was employed due t o the physical characteristics of the system. The model was further simplified by describing vertical transport by diffusion alone. Using observed total dissolved solids concentrations, a method was developed during the study for establishing the vertical diffusion coefficient as a function of depth. A unique feature of this water quality modeling technique is that it allows the seasonal distribution of a quality constituent to be studied without the necessity of developing a hydrodynamic model of the system . The advective transport is designed to be input to the model based on observed long term circulation patterns . In the case of Great Salt Lake, circulation patterns are not yet well known. However, approximate patterns h a ,, e been established from some observations to date , and those were used to provide preliminary tests of the validity and response characteristics of the model. These tests have demonstrated that the model will be a practical and useful tool for monitoring the distribution of quality constituents within the lake.

I designed a suite of studies in coordination with Utah Division of Wildlife Resources (UDWR) to evaluate waterfowl use of the GSL in winter and ecological aspects associated with GSL use. These studies provided insight into key information gaps previously identified by UDWR regarding management of GSL resources. Population surveys indicated total duck abundance was low when GSL surface elevations were low and wetland resources diminished because of persistent drought in the system. Also, ducks appear to use hypersaline parts of GSL more when freshwater habitats are limited from either drought or ice conditions. Common goldeneye, northern shoveler, and green-winged teal exhibited the most use of hypersaline areas. Dietary evaluations indicated all three species feed on hypersaline invertebrates from GSL to meet energetic and nutritional needs in winter. Brine shrimp cysts were important foods for northern shoveler and green-winged teal. Fat levels of ducks are important determinants of survival and fitness. Fat reserves of goldeneye were generally lower in the winter when both GSL and wetland habitat resources were lower. Results suggest brine fly larvae productivity, freshwater habitat availability, and temperature and wind speed likely play a more prominent role in goldeneye fat reserves than osmoregulation. Also, common goldeneye and northern shoveler using the GSL apparently accumulated biologically concerning amounts of mercury and selenium during winter. However, further research is needed to evaluate the effect of these elements on GSL ducks.

A two-dimensional, finite-element, porous-media flow model is developed to simulate stratified bi-directional flow of brine through the earth embankment carrying the Southern Pacific Railroad across Great Salt Lake. The model is part of a two-year research program whose objective is to develop a computer model of circulation in Great Salt Lake. This overall model is to be used as a predictive device for salinity distributions and circulation patterns in the lake. The porous media flow model is designed to establish flow rates through the Southern Pacific Railroad causeway embankment which traverses the north central part of he lake and divides it into two bodies of water. The study first develops the mathematical equations which describe two-dimensional stratified bi-directional flow of a fluid through porous media. Next , the problem is numerically posed as a boundary value problem in terms of pressure. This formulation is then solved by an iterative finite element scheme which employs quadratic, isoparametric, quadrilateral elements. The study also investigates two possible means of performing an analysis of stratified bi-directional flow with a pressure formulation by either posing the problem as a single boundary value problem with two densities of fluid within, or as two single-density boundary value problems coupled at the density interface. The single boundary formulation did not converge with the techniques attempted due to numerical instability at the density interface. The numerical model developed enables one to calculate fluid flow rates as well as the locations of the free surface and density-interface. The model simulation investigates many lake variables which affect brine flows through the embankment. Realistic model parameters are used which cover the range of actual values observed on the lake for the years 1968 through 1972. The numerical results presented in the study are given in terms of generalized dimensionless variables. The numerical results appeared to be in agreement with previously performed stratified bi-directional Hele-Shaw model studies. The major lake parameters affecting flow rates through the causeway were the free surface head difference, the southside lake surface elevation and the difference in fluid densities between the upper and lower layers of the embankment . The southward density flow was found to be completely cut off for certain combinations of lake parameters. Lack of adequate field data collected on the embankment has left both the geometry and the coefficient of permeability of the fill in question, preventing a rigorous verification of the model' s ability to predict actual flows. More field data are also necessary to establish whether there is stratification on the north side of the embankment which can greatly affect flow calculations. A high Reynold's number was found for flow through the embankment, raising a question as to the validity of the Darcian flow assumption used in the analysis. However, the establishment of the true Reynold's number can only be verified through the collection of more empirical data.

To meet the surging water demand due to rapid population growth and changing climatic conditions around the world, and to reduce the impact of floods and droughts, comprehensive water management and planning is necessary. Climatic variability, hydrologic uncertainty and variability of hydrologic quantities in time and space are inherent to hydrological modeling. Hydrologic modeling using a physically-based model can be very complex and typically requires detailed knowledge of physical processes. The availability of data is an important issue to justify the use of these models. Data-driven models are an alternative choice. This is a relatively new and efficient approach to modeling. Data-drive models bridge the gap between the classical regression and physically-based models. By using a data-driven model that relies on the machine learning approach, it is possible to produce reasonable predictions from a limited data set and limited knowledge of underlying physical processes of the system by just relating input and output. This dissertation uses the Multivariate Relevance Vector Machine (MVRVM) and Support Vector Machine (SVM) for predicting a variety of hydrological quantities. These models are used in this dissertation for identifying influential climate indicators, and are used for long-term streamflow prediction for multiple lead times at different locations in Utah. They are also used for prediction of Great Salt Lake (GSL) elevation series. They provide reasonable predictions of hydrological quantities from the available data. The predictions from these models are robust and parsimonious. This research presents the first attempt to identify influential climate indicators and predict long lead-time streamflow in Utah, and to predict lake elevation using machine learning models. The approach presented herein has potential value for water resources planning and management especially for irrigation and flood management.

The Great Salt Lake (GSL) wetlands account for ~75% of all Utah wetlands and provide not only critical habitat for millions of migratory birds, but also provide valuable ecosystem functions and services as well as economic benefits to Utahns. However, these wetlands are facing an aggressive invader, Phragmites australis, that has spreading across the GSL wetlands and replacing native wetland habitats. Wetland managers have spent countless resources and time trying to control the spread of P. australis and restore GSL wetlands. However, we do not fully understand how these wetlands functions and services are being altered with this habitat homogenization because functional data for our wetland species have not been well documented. This lack of knowledge may hinder wetland restoration efforts. To create baseline functional data for the GSL wetland species and better understand how the spread of P. australis might be affecting the overall health of the system, I measured eight individual ecosystem functions for seven dominant habitat types found across the GSL wetlands. I compared these individual functions across habitat types as well as created two different multifunctionality indices using an averaging and a thresholds approach. With these comparisons, I was able to determine the distinct functional strengths of different wetland habitat types and their overall functional abilities. I found that functional abilities varied greatly by habitat type and that not one single habitat could support every function even at the lowest threshold measured. I found that Typha latifolia, Schoenoplectus acutus, and P. australis, had the highest multifunctional values. However, I also found that some habitats offered unique functions, such as Salicornia rubra and playa, and that these functions were lacking in other habitats, including the most multifunctional habitats. These findings suggest that maintaining habitat heterogeneity will be critical in ensuring a fully functioning wetland system that can provide a multitude of ecosystems services that benefit both humans and wildlife. The findings of this study will supply wetland managers with a better understanding of the functional strengths of different wetland habitats. This data will aid in ongoing restoration efforts by enabling managers to target certain functions and create more efficient and effective management plans.