Environmental & Conservation Sciences Masters Theses

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Environmental and Conservation Sciences Program, College of Graduate and Interdisciplinary Studies
(North Dakota State University, 2011) Jenkins, Samuel George
This study offers an insight on pertinent parameters that may be considered to address potential emerald ash borer {EAB), Agrilus p/anipennis, infestation. The study utilizes a geospatial model, calibrated using empirical data from Ohio, to model risk of EAB introduction to North Dakota. A spectral library of native trees was also developed to aid in rapid identification of ash tree locations. In light of this imminent threat to North Dakota, a concerted effort to inventory and provide deterministic or stochastic models is critical for providing likelihood scenarios to a consortium of affiliated forest health partners. The premier goal is to mobilize first-responders to alleviate, mitigate or quarantine an affected area and develop plans to minimize the economic impact of an EAB infestation. A cohort study of an existing EAB infestation in Ohio was used to calculate relative risks for proximity to three categories of human infrastructure and ash trees themselves. The relative risks were then used to identify areas in North Dakota that would most be at risk. The results of the risk model show large areas in the eastern part of North Dakota and large swaths of land that have native forest cover, for example, Turtle and Killdeer Mountains, would be most prone to EAB.
The Formation and Evolution of the Stockton Island Tombolo, Refined by OSL Geochronology
(North Dakota State University, 2022) Schnucker, Sara Gibbs
Past research conducted on strandplain sequences has shown strandplains can record Holocene lake level changes. The Stockton Island tombolo, of the Apostle Islands National Lakeshore, holds such a record within its eastern and western strandplains; however, its data is at risk of being erased due to its position in a region of subsiding glacial isostatic adjustment. The objectives of this study were to provide geologic dates to evaluate the formation and evolution of the tombolo, as well as assess an apparent truncation of the western strandplain by the eastern. 19 samples were collected along transects from ridges within each strandplain. Samples were dated using Optically Stimulated Luminescence (OSL) techniques. These age results will provide useful geochronological context for future ecological and archaeological research on the tombolo; they will also provide a more robust understanding of past lake level variations which may enhance public education on water resources and climate change.
In situ Quantification of Hydrogel Entrapped Microbial Cells
(North Dakota State University, 2010) Wadhawan, Tanush
Entrapped bacteria are used in several applications including food and beverage production, antibiotic production, and wastewater treatment. To date in order to determine the viability of entrapped bacteria, they have to be de-entrapped from the matrix first. However, cell de-entrapment procedures, such as matrix dissolution by acid or heating at high temperatures, may affect the viability of the cells. In this study, three viability assays were assessed for in situ estimation of the number of entrapped cells. Also, a new method was developed to determine the effect of entrapment procedures on bacterial cell viability using one of the three assays, LIVE/DEAD® BacLight™ Bacterial Viability Kit. The other two quantitative assays used in this study were the bioreducible tetrazolium salt (XTT) assay and the adenosine triphosphate (ATP) based assay. The applications of the assays and the new method were performed on two cell entrapment techniques widely used in environmental applications, phosphorylated-polyvinyl alcohol (PPV A) and calcium alginate (CA). The data from the XTT and ATP assays showed linearity and strong correlations between the viability signals and number of beads in which each bead contained a similar number of live cells. An application of the XTT assay on the PPV A entrapped bacterial beads was an exception to these results. Effects of the acid and heat dissolution deentrapment procedures on cell viability were also evaluated by using both assays and a traditional plate count method. The heating process showed the greatest reduction in bacterial viability when compared to the other de-entrapment procedures. The ATP assay is a more sensitive and less time consuming approach for viability estimation when compared to the XTT assay and traditional plate count method. Both XTT and ATP assays have potential for use in quantifying the viability of entrapped bacteria. The new method developed for determining the effect of entrapment procedures on bacterial cell viability involved entrapping bacteria directly onto glass slides. This new method was compared with traditional approaches which require dissolution of the entrapment matrix using chelating agents and heat. Both the developed and traditional methods require labeling with fluorescent dyes from the LIVE/DEAD® assay and observing and quantifying live and dead cells under fluorescence illumination. The viability of entrapped cells was compared to the viability of free cells prior to the entrapment. The developed method was applicable to both PPV A and CA entrapped cells. Both methods indicated that the entrapment procedures resulted in reductions in cell viability, but the new method showed less viability reduction than the previously used method. This suggests that the matrix dissolution prescribed in the traditional method negatively affected cell viability and the new method is therefore more reliable. The percent of live bacterial cells before the entrapment ranged from 54 to 74%, while the percent of live cells following the entrapment based on the new method was 39 to 62%. The approach used in the method could potentially be adopted for other cell entrapment techniques.
Interactions of Iron Nanoparticles with Microorganisms
(North Dakota State University, 2010) Shabnam, Rabiya
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Intra- and Inter-Specific Variation in Plant Responses to Climate Change
(North Dakota State University, 2022) Chandler, Emma
Plants are sensitive to changing climates and are vulnerable to environmental conditions. In many regions, climate change is shifting temperatures and precipitation patterns, both of which affect various traits in living organisms, including those linked to survival and reproduction. Understanding how plants respond to climate change is increasingly important for conservation efforts. We addressed sources of trait variation and the responses utilized to cope with changing conditions within and among plant species in three different studies. We found evidence of local adaptation in temperature tolerance presumably due to divergent selection across geographic distance in Solanum carolinense. In the same species, we found phenotypic plasticity in reproductive traits when exposed to heat. Lastly, we determined that flowering phenology is driven by temperature in tallgrass prairie herbs rather than winter precipitation. These studies provide examples of how plant species are vulnerable to changing temperatures but have the capacity to adapt or acclimate.
Late Pleistocene Mountain Glacier Equilibrium Line Altitudes and Paleoclimate Reconstruction in the Great Basin
(North Dakota State University, 2022) Walter, Larkin
This thesis presents new reconstructions of paleoglacier surfaces and Equilibrium Line Altitudes in nine mountain ranges in the northeastern Great Basin during the Last Glacial Maximum. Improved methods for paleoglacier and ELA reconstructions were applied in this thesis, using a computationally derived toolset presented by Pellitero et al. (2015, 2016). Additionally, the first computationally derived volume estimates for alpine paleoglaciers in Lake Bonneville are presented. These reconstructions, in addition to 10Be cosmogenic exposure ages taken from the ICE-D website, were used together to further limit the magnitude and climate of the Last Glacial Maximum. Equilibrium Line Altitudes provide a vital link between the mass balance of a glacier and its relationship with climate. Reconstructing these relationships in the Great Basin showed the regional maxima did not coincide with the Lake Bonneville highs stand and the melting of glaciers following the LGM was not the driving factor in the Lake overflow.
Mycorrhizas and the Context Dependency of Mutualism: Effects of Soil Phosphorus Availability and Community Composition of Arbuscular Mycorrhizal Fungi on Plant Performance and Symbiosis With the Grassland Forb Gaillardia aristata Across Its Northern Range
(North Dakota State University, 2021) Long, Alison
Arbuscular mycorrhizal fungi (AMF) colonize roots and provide phosphorus as well as other benefits to hosts in exchange for photosynthate. I explored how the symbiosis between AMF and the native prairie forb Gaillardia aristata differed regionally among sites that varied in soil phosphorus availability (SPA). In the field, plant biomass and shoot phosphorus concentration were correlated with SPA and hyphal length. AMF community composition in roots correlated with distance between sites, SPA, temperature, and precipitation. To test the hypothesis that AMF from sites varying in SPA would differ in effectiveness at provisioning phosphorus to their host, I grew G. aristata in the greenhouse with soil inoculum from sites low and high in SPA and fertilized with or without phosphorus. Gaillardia aristata benefited equally from both inocula and phosphorus fertilization, while root AMF communities differed between inocula but not with fertilization. AMF from varying SPA appear to be equally effective mutualists.
Pupfishes as a System to Test the Predator Naiveté Hypothesis
(North Dakota State University, 2022) Anderson, Cody Marie
Pupfishes are an ideal system to test this the predator naiveté hypothesis because they often occur in isolated springs across a gradient of predation pressure. A convenient tool for assaying antipredator competence are behavioral responses to chemical alarm cues released when the epidermis is damaged during a predation event. Behavioral responses of three pupfish species, Red River Pupfish (Cyprinodon rubrofluviatilis), Amargosa River Pupfish (C. nevadensis amargosae), and Shoshone Pupfish (C. n. shoshone), which occur across a gradient of community complexity and predation pressure, were evaluated to test the effect of community composition, including predator variety and density, on antipredator behaviors. All three species responded to alarm cues by either reducing activity and/or lowering position in the water column, regardless of respective isolation or predation risks. I found no support for the predator naiveté hypothesis in these populations, which suggests that pupfish can be managed in multi-species habitats.
Soil Warming and Drying and the Consquence to Crop Yields among Conservation Tillage Practices in Frigid Corn-Soybean Fields
(North Dakota State University, 2017) Alghamdi, Rashad Saeed
Concerns over delayed soil warming and drying have hindered adoption of conservation tillage practices in frigid environments. Our objectives were to evaluate the effects of chisel plow (CP), vertical tillage (VT), strip tillage with coulters (STC), and strip tillage with shanks (STS) on soil warming and drying and their potential consequences to crop yields. A two-year study was conduct at three full-scale, producer-managed, corn-soybean fields in the Red River Valley of eastern North Dakota and western Minnesota. Tillage treatments were assessed to measure crop residue cover, soil temperatures, soil volumetric water contents, crop yields, and other metrics. Our study indicated significant differences for many soil physical and chemical parameters, but little to none for soil warming and crop yields. Yield differences were attributed to varying fertilizer management practices, timing, and application method. These findings emphasize the importance of field management practices that compliment conservation tillage for obtaining competitive crop yields.
Souris River Dissolved Oxygen Study in Support of Total Maximum Daily Load Development
(North Dakota State University, 2010) Super, Joseph James
The Souris River, a slow moving praire river, originates in the Canadian province of Saskatchewan. The Souris River enters into the United States near Sherwood, North Dakota. The upper portion of the Souris River, from the border with Saskatchewan, Canada to Lake Darling, a total of 43 .4 miles, has been on the North Dakota Section 303(d) Environmental Protection Agency (EPA) list of impaired waters since 1998 (NDDoH, 2008). Low dissolved oxygen (DO) concentration in the river has been problematic, resulting in fish kills on the upper reach of the Souris River. The primary goal of the project is to determine source(s) of contaminations that cause seasonal variation in dissolved oxygen concentration. Objectives ofthis research include: 1) studying the nature and extent of the impairment using existing data, 2) executing a comprehensive year long sampling plan, and 3) analyzing sample data to identify the major sources of DO impairment. Results from this study will be used by North Dakota State Department of Health (DoH) for development of a Total Maximum Daily Load (TMDL) report to the EPA. The reach was expanded into Canada, totalling 52 river miles, between Glen Ewen, Saskatchewan, CA and Mouse River Park, ND. This reach was sampled 29 times during the period of this study. During winter months, DO under the ice was constantly below 1 mg/L. During the summer diurnal swings of DO caused the stream to fall below the designated 5 mg/L standard in the early morning hours. Sediment oxygen demand was determined to be the main stressor. Two contaminant sources that contribute to DO variation on the Souris River were identified, livestock ranching practices and the physical alteration of the river. Ranching is the leading cause of impairment. Livestock in the riparian area contribute organic inputs and stream bank erosion. Physical alterations lead to DO variation in two ways. Upstream impoundments eliminate scouring flows allowing sediment to build up. Downstream impoundments back up water into study reach contributing to sedimentation. Low head dams create hydrologic flow issues which lead to dissolved oxygen depletion.
Trace Element Distribution in Soils of The Pembina Escarpment, North Dakota
(North Dakota State University, 2010) Jyoti, Vijaya
Association of element concentrations for soils of northeastern North Dakota formed from different sources of parent materials were determined based on geochemical data. These soils overlie the Cretaceous Pierre Formation and parent materials consist of shale rich glacial till, residual shale, and colluvial materials. Surface and core sampling locations included a cropped field, Conservation Reserve Program land, and grassland fields in a North Dakota State Wildlife Management Area. Samples were analyzed for cadmium and other trace elements using a nitric acid digestion followed by optical emission spectroscopy. Results of a preliminary study in cropped and CRP fields showed elevated concentrations of cadmium. Later comprehensive field work in a Wildlife Management Area was carried out to examine the landscape scale variation for a suite of elements. Morphologic and laboratory analysis of soil cores indicate high clay content with mixed clay mineralogy, indicative of the influence of shale residuum on the parent materials of the escarpment soils. Chemical properties of the escarpment soils revealed high levels of organic matter (2.62-13.30 %), ultra acidic to slightly alkaline pH range, and low electrical conductivity for the soils. Average cadmium concentration of 0.28 mg/kg was reported for the samples from eight cores while 16.4 mg/kg cadmium was found in the CRP field sample. Correlations of different analytes with cadmium showed significance with shale and argillic horizons. Principal Component Analysis revealed that elevated trace element concentrations for the soils in northeastern North Dakota are linked to a variety of factors including organic matter content, clay mineralogy, pH, elevation, and electrical conductivity. Results of this study suggest that lateral as well as vertical water movement of water could be an important factor leading to transport and elevated trace metal zones in these soils.
Using Seed Source Diversity and Species Distribution Modeling for Evaluating Grassland Restoration Success and Suitability
(North Dakota State University, 2022) Lindstrom, Jess
Seed sourcing for restoration often uses local populations presumed adapted to local environments. This may not be effective under changing climates. Thus, different seed sourcing strategies need testing including multi-source regional collections and their ability to persist in response to change. We compared first-year emergence for single and multi-source seed mixes on plant community diversity following restoration at two locations. There was no discernable effect of seed mix treatment on community establishment. However, land-use history likely has influenced early diversity. Following this, we evaluated which climate variables influence distributions across 26 grassland species’ ranges. We produced contemporary species distribution models and evaluated how predicted habitat suitability changed in response to predicted carbon emission scenarios. The climate variables that influenced habitat suitability varied by species with predicted species- and functional-group specific responses to predicted change. These results may aid seed sourcing decisions and identifying regions to implement restorations in the future.

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