Environmental & Conservation Sciences

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Research from the Department of Environmental & Conservation Sciences. The department website may be found at https://www.ndsu.edu/ecs

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Paleoclimatic Interpretation of the Moorhead Low Water Phase of Glacial Lake Agassiz in the Southern Basin based on Fossil Coleoptera Assemblages
(North Dakota State University, 2009) Rock, Jessie Lee
See submission document for full abstract.
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.
Interactions of Iron Nanoparticles with Microorganisms
(North Dakota State University, 2010) Shabnam, Rabiya
Nanoparticles (
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.
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.
Body Shape Divergence Among Wild and Experimental Populations of White Sands Pupfish (Cyprinodon Tularosa)
(North Dakota State University, 2011) Kowalski, Brandon Michael
Reports of contemporary evolution have become ubiquitous, but replicated studies of phenotypic divergence for wild populations are exceptionally rare. In 2001, a series of experimental populations were established to replicate a historic translocation event that led to a case of contemporary body shape evolution in the White Sands pupfish. Using landmark-based geometric morphometric techniques I examined phenotypic variation for seven of these populations, and two wild populations over a 5 year period (5-10 generations) in the field. Significant body shape divergence was observed, but divergence patterns were not parallel, suggesting that the ponds were ecologically dissimilar. Considerable body shape variation found among populations suggests that the observed divergence maybe governed by temporal environmental variance. In this study, body shape variation was correlated with population density. These data suggest that habitat intrinsic factors or unmeasured habitat features may have strong affects on body shape, warranting continuous monitoring of recently translocated fishes.
Sedimentology and Stratigraphy of Miocene-Age Glacial Deposits, Friis Hills, Antarctica
(North Dakota State University, 2011) Smith, Alexander Ryan
The Friis Hills is an isolated plateau standing as much as 600 m above surrounding topography in the McMurdo Dry Valleys region or Antarctica.Preserved on the plateau surface is a sequence of early to middle Miocene-aged dritis. At the eastern edge of the plateau, these drifts fill a shallow paleovalley to a depth of at least 35 m. The drills are exposed in a natural cross-section where modern topography crosscuts the paleovalley. Establishing an age and an environmental interpretation for these deposits is important because Antarctic paleoclimate records are lacking from the Mid-Miocene Climate Optimum. Two drifts fill the ancient paleovalley in the eastern Friis Hills. The upper drift is here named Cavendish drift: the lower is here named Friis drift. Cavendish can be subdivided into three units, whereas Friis drift can be subdivided into two units. Each of these units is a horizontal bed that laps on paleovalley sidewalls. The lowest, Friis II, is a compact diamicton that is overlain by a nearly in-situ bedded volvanic ash. Based on [20]Ar/[39]Ar dating, the ash is 19.76 [plus/minus] 0.07 Ma old. A second diamicton, Friis I, conformably blankets Friis II and was discovered to hold fossileferous interbeds. Both Friis I and II contain erratic clasts and both are lodgemont tills deposited from small, locally derived, alpine glaciers. Bedrock striations show ice flow to the northeast at azimuths between 025° to 032°, parallel to the trend of the paleovalley axis. Above these, Cavendish I. II. and III were deposited when thick ice covered the Friis Hills. Where the Cavendish drift laps onto paleovalley sidewalls, bedrock striations show ice flow from 077° to 150°. Cavendish drift was deposited sometime alter 19.8 Ma but before 14 Ma. when the Dry Valleys glacial records show that regional glaciers became cold-based. Downcutting eventually isolated the Friis Hills plateau, resulting in the preservation of the drift sequence. This event was most likely associated with growth or the East Antarctic Ice Sheet 14 Ma ago. This age constraint means that the tills preserved in the Friis Hills date from a time just before the East Antarctic Ice Sheet expanded and became a permanent feature. Based on the age-dated stratigraphy presented in this thesis, future work focusing on fossiliferious interbeds could provide unique and important constraints on Miocene climate change.
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.
Multi-Element Composition of Triglochin Maritima L. from Contrasting Habitats including Hot Springs and Metal Enriched Areas
(North Dakota State University, 2011) Sunwar, Sharmila
The aim of this PhD research was to study multi-element composition in wetland plants from contrasting habitats, including hot springs, temporary wetlands, and metal-rich areas. Triglochin maritima L. (seaside arrowgrass) was chosen for the study because this species is common in alkaline/saline soils and is adapted to diverse habitats. Eleocharis rostellata, Juncus balticus, Salix exigua, S. boothii, and S. wolfii were also included in the study. Field studies and greenhouse experiments were conducted to study the multi-element composition in plants. In the greenhouse experiment the effects of temperature and soil biota on multielement uptake in T. maritima were studied. Root-zone soils and plant samples were analyzed for 32 - 50 elements using inductively coupled plasma OES/MS spectrometry. The expected outcomes from this research were: 1) the development of multi-element fingerprints for T. maritima and other plant species from contrasting habitats, and 2) a better understanding of the effects of temperature and soil biota on multi-element uptake in T. maritima. Habitat specific element concentration patterns in T. maritima were observed; concentrations of Mn, Li, and B were high in plants from hot spring influenced wetlands, whereas Ca, P, Mg, Fe, Sr, Ba, Ti, and Cu were higher in the plants of temporary wetlands. J. balticus and Salix species from mine impacted and uncontaminated sites revealed distinct differences in multi-element fingerprints. J. balticus showed high concentrations of S, K, Mn, Fe, Cu, Al, As, and Cd at contaminated sites compared to un-contaminated sites. Multi-element fingerprints of Salix species showed that S. boothii had higher concentrations of Mn, Fe, Al, and Ti compared to S. exigua and S. wolfii. To our knowledge for the first time the association of mycorrhizal fungus in T. maritima was confirmed, and significant effects of temperature on element concentrations, contents, and their translocation in plants were observed. Generally, the distribution of the total contents of P, Na, Mn, B, Cu, Mo, Li, Sr, Ti, and Cs in both roots and leaves were lower at 40 °C compared to 20 and 30 °C, but their distribution and translocation from root to leaves were higher at 40°C. Even though the biological and physiological functions of Li, Sr, Ba, Rb, and Ti in plants are not fully understood, these elements were substantially taken up by T. maritima, and significant positive correlations of these elements were found with elements that have known biological functions. Overall, concentrations of Ca, P, Mg, Mn, B, Sr, and Ba in T. maritima showed variation due to differences in habitats, temperature, and experimental growing conditions (greenhouse and field condition). Concentration patterns of Na, K, and Zn were species specific and affected by temperature. Li concentrations varied due to habitat differences, growth conditions, and species differences. Future research directions could include: 1) identification of the fungal species associated with T. maritima and studies to elucidate their possible role in survival of T. maritima in the elevated temperature of hot springs, 2) the effects of soil factors, such as salinity and 3) seasonal variation in uptake and translocation, particularly for the less studied elements with yet unrecognized but potential biological functions in plants.
Multi-Element Fingerprinting of River Sediments to Identify Diffuse Pollution Sources
(North Dakota State University, 2011) Wijeyaratne, Dimuthu Nilmini
This study was carried out in the Souris and Turtle Rivers in North Dakota. The aim of this study was to develop multi-element fingerprints of the Souris River and Turtle River sediments and to evaluate the suitability of these fingerprints to assess the geographic origin of potential pollutants of the two rivers. Preliminary analysis of Souris River sediment samples confirmed that the multi-element fingerprinting can be used to assess the sediment and contaminant loading patterns. Laboratory experiments were performed to assess the validity of linear mixing assumption in multi-element fingerprinting studies. The results of these experiments verified the assumptions and showed that there is a statistically significant spatial and temporal variation in the element concentrations depending on their mobility and re-deposition. Field studies were conducted in the Souris River and Turtle River to assess the variation of element concentrations in the top riverbed samples along the main rivers and their tributaries. The sediment contribution from the tributaries and the phosphorus concentrations in the main channel were used to calculate the phosphorus contributions from the tributary sediments to the Souris River. The differences in phosphorus contributions from tributaries were related to land use, underlying geology, and the size of the watersheds of the tributaries in the Souris River watershed. Similar analysis was used in the Turtle River to calculate Arsenic, Cadmium and Selenium contribution from the tributaries to the Turtle River. The differences in the contribution of these elements were related to the underlying geology and the size of the watersheds. This study provides a detailed analysis of element concentrations and relative sediments and element loading rates from the tributaries to the main rivers along the Souris and Turtle Rivers in North Dakota. The multi-element fingerprinting technique can be successfully used as a tool to identify the relative contribution of sediments and assessing and tracing pollution sources in rivers. Multi-element fingerprinting provides a relatively low cost, rapid tool for sediment tracking, without the need for addition of exotic chemicals such radio-tracers or dyes to natural ecosystems.
Effects of Nanoscale Zero-valent iron (nZVI) on Bacterial Viability: Roles of Growth Phases and Oxidative Stress
(North Dakota State University, 2011) Krittanut, Chaithawiwat
The effect of nanoscale zero-valent iron (nZVI) particles on bacteria from different growth phases was studied. Four bacterial strains including Escherichia coli strains JMI09 and BW25 l l 3, and Pseudomonas putida strains KT2440 and Fl were experimented. The growth characteristics of these strains were detennined. Their cells were harvested based on predetermined time points corresponding to different growth phases and exposed to nZVL The cell viability was determined by a plate count method. The cells in lag and stationary phases showed higher resistance to nZVI for all four bacterial strains, whereas the cells in exponential and decline phases were less resistant and were rapidly inactivated when exposed to nZVI. Bacterial inactivation increased with the concentration of nZVI. Furthermore, less than 14% reduction in viability was observed when the cells were exposed to the leachate of nZVI suspension suggesting that the physical interaction between nZVI and the cells is critical for bacterial inactivation. To understand the physiology that underlines these phenotypes, the responses from various oxidative stress gene knockout strains of E. coli BW25 l l 3 to nZVI were examined. For each of these mutant strains, cells from different growth phases were collected and exposed to nZVI. The viability of the cells was determined by a plate count method. All of the mutant strains exhibited higher susceptibility to nZVI when compared to the wild type strain. The results also indicated that different knockout strains exhibited different levels of susceptibility to nZVI. Strain lacking RpoS, a global stress regulator, showed the highest susceptibility. Among different defensive enzyme mutants, sodA and sodB mutants exhibited the highest vulnerability whereas sodC mutant revealed much less susceptibility, suggesting that nZVI may induce oxidative stress inside the cells via superoxide generation. The inducibility of catalase (hydroperoxidase I) was also investigated by exposing the cells to nZVI and measuring a related gene expression using quantitative polymerase chain reaction. Results suggested that nZVI repressed the expression of this enzyme.
Ecological and Sociological Considerations of Wind Energy: A Multidisciplinary Study
(North Dakota State University, 2012) Bicknell, Lucas J.
Wind energy is quickly becoming a critical technology for providing Americans with renewable energy, and rapid construction of wind facilities may have impacts on both wildlife and human communities. Understanding both the social and ecological issues related to wind energy development could provide a framework for effectively meeting human energy needs while conserving species biodiversity. In this research I looked at two aspects of wind energy development: public attitudes toward wind energy development and wind facility impacts on local bat populations. These papers present aspects of wind energy development that have been the subject of increasing study. This preliminary research is intended to demonstrate the responsibility we have to making well-informed decisions as we continue to expand wind energy development. Additionally, I hope to generate interest in interdisciplinary study as a means to broaden the scope of research by making use of the diverse tools available within different disciplines.
Attenuation of Nitrate from Simulated Agricultural Wastewater Using an Immobilized Anaerobic Biofilm
(North Dakota State University, 2012) Anar, Mohammad Jahidul
A number of methods are currently in use for attenuating nitrates from wastewater with varying degrees of efficiency. Bioremediation using bacteria may be an efficient and cost effective method. In an anaerobic bioremediation system, nitrate can replace carbon dioxide as an electron acceptor and aids in nitrate attenuation by assimilatory reduction. The purpose of this study was to investigate nitrate attenuation in a hyperfiltration system using a pure culture of strictly anaerobic, facultative Methanobrevibacter ruminantium bacteria. Filtration experiments were conducted using amalgamated Na- montmorillonite clay-glass beads compacted at 500 psi differential hydraulic pressure with or without a biofilm. A simulated agricultural wastewater of 3.105×10-4 moles/L of NO3- was bioremediated. The use of bacteria in attenuating nitrates offers promising results on a bench-scale.
Population Genetics of the Western Prairie Fringed Orchid
(North Dakota State University, 2012) Ross, Andrew August
The Western Prairie Fringed Orchid (WPFO) Platanthera praeclara is listed as a federally threatened species in the United States. The habitat of the WPFO is highly fragmented, causing the possibility of genetic isolation among populations. I assessed microsatellite polymorphism in eight WPFO populations using six polymorphic microsatellite markers. High levels of within population genetic diversity were found: 12.5 alleles per locus and mean expected heterozygosity (HE) of 0.622. The genetic structure among the populations was weak; the overall FST value was 0.0692. A mantel test showed no correlation between genetic and geographic distance r = 0.2793 (P = 0.31). The genetic diversity and genetic structure is comparable to other plant species. Significant inbreeding many be occurring as indicated by a FIS value of 0.1903. More studies with the developed markers are necessary over a larger part of the geographic range of WPFOs to determine if other populations are genetically isolated.
Developmental Changes in Fat Metabolism of Tobacco Hornworm, Manduca Sexta
(North Dakota State University, 2012) Thapa, Gita
Insects fed high carbohydrate diets have increased fat storage, and excess fat storage in insects may have fitness costs. M. sexta larvae reared on 5.6% fat diet had lower body mass and growth rate compared to those on 3.4% fat or 0.4% fat diets. Fifth instar caterpillars fed high-fat diet ate less food but had higher approximate digestibility than the low-fat diet fed caterpillars. Analysis of fat body and fecal pellet lipid content showed high-fat diet fed caterpillars stored and excreted more lipids than low-fat diet fed caterpillars. To test the hypothesis that increased dietary fat alters lipid transport, we measured mRNA expression of apolipoproteins I and II, proteins for transporting lipids. Expression of apolipoproteins I and II did not differ with dietary fat. Negative feedback from fat intake could inhibit feeding via endocrine pathways. This research will increase our understanding of the regulation of feeding in caterpillars.
Micro-Pore Parametrics for Optimal Hyperfiltration of Conservative Contaminants
(North Dakota State University, 2012) Wamono, Anthony Walekhwa
In compacted Na-montmorillonite membranes, the pore-size, and surface charge will influence filtration processes of solutes. A dead-end hyperfiltration setup was utilized to: (a) study the intrinsic retention, membrane filtration coefficient, and solution flux of different membrane configurations and (b) model nitrate break-through effluent concentrations through the membrane. Scanning electron microscopy and solute analytical techniques were employed to assess what critical components of micro-pore parametrics would prevail in a non-bio stimulated remediation of simulated agricultural wastewater. Although high content bentonite membrane configurations (5 g clay at 2500 psi) offered better solute rejections with a 30 percent increase in the cell concentration, the compaction of the membrane had the most deterministic influence on the solution flux. The results reveal hyperfiltration of nitrate ions is a function of the compaction pressure and composition of bentonite in the mixed soils. High content bentonite membranes compacted at the optimal pressures offer promising solutions to nitrate contaminant remediation.
Biogeochemistry of Wet Ecosystems from Root Zone to Landscape
(North Dakota State University, 2012) Kissoon, La Toya Tricia
The biogeochemistry of wetland ecosystems varies, causing them to act as sources, sinks, filters or transformers of nutrients and pollutants. Wetland plants play important roles in the cycling of elements in wet ecosystems. The structural and physiological adaptations that allow these plants to colonize wetland habitats as emergent or submerged species contribute to biogeochemical processes in wetland substrates. Rhizosphere (root zone) oxidation, iron and manganese oxide precipitation, acidification of the rhizosphere, root exudation, and microbial activity influence the mobility of elements in wetland substrates. Both emergent and submerged wetland plants can alter conditions in the rhizosphere that influence the mobility of elements. These plants are also capable of removing elements such as Cd, Cu, Fe, Mn, N, P and Zn from solution and accumulating them in their tissues. Root zone studies were carried out in the greenhouse using the wetland plants Typha angustifolia (cattail) and Rumex crispus (curly dock) and in the field using Triglochin maritima (seaside arrowgrass) to determine differences in element concentrations in the root and bulk zone under different soil moisture conditions. Studies involving shallow lakes of Minnesota were carried out to determine relationships among (1) landscape variables (e.g. lake watershed size, percent agriculture, percent woodland), water and sediment characteristics (turbidity, chlorophyll-a, organic content, particle size), (3) element concentrations in waters and sediments, and (3) plant abundance and community composition. The studies reported here showed that different factors influenced the distribution of multiple elements in the root zone of emergent wetland plants and in waters and sediments of shallow lakes. First, the root zone studies indicated that pH, redox and moisture content of wetland soils influenced the distribution of elements in the rhizosphere and subsequent uptake of these elements by wetland plants. Second, the shallow lake study showed that land cover uses (agriculture and woodland), lake watershed size, and sediment physical characteristics (organic content and particle size) influenced the distribution of elements in waters and sediments of shallow lakes. Concentrations of these elements, land cover uses, open water area, turbidity, chlorophyll-a concentrations and sediment physical characteristics influenced abundance and distribution of submerged and floating plants.
Phosphate Removal and Recovery Using Iron Nanoparticles and Iron Cross-Linked Biopolymer
(North Dakota State University, 2012) Almeelbi, Talal Bakheet
Nanoscale zero-valent iron (NZVI) particles and iron cross-linked alginate (FCA) beads were successfully used for the first time for phosphate removal and recovery. NZVI was successfully used for phosphate removal and recovery. Batch studies indicated a removal of ~96 to 100% phosphate in 30 min (1, 5, and 10 mg PO43--P/L with 400 mg NZVI/L). Phosphate removal efficiency by NZVI was 13.9 times higher compared to Microscale ZVI (MZVI) particles. The successful rapid removal of phosphate by NZVI from aqueous solution is expected to have great ramification for cleaning up nutrient rich waters. The presence of sulfate, nitrate, and humic substances and the change in ionic strength in the water marginally affected phosphate removal by NZVI. A maximum phosphate recovery of ~78% was achieved in 30 min at pH 12. Novel iron cross-linked alginate (FCA) beads were synthesized, characterized and used for phosphate removal. The beads removed up to 37-100% phosphate from aqueous solution in 24 h. Freundlich isotherm was found to most closely fit with experimental data and the maximum adsorption capacity was found to be 14.77 mg/g of dry beads. The presence of chloride, bicarbonate, sulfate, nitrate, and natural organic matters in aqueous solution did not interfere in phosphate removal by FCA beads. The phosphate removal efficacy FCA beads was not affected due to change in pH (4-9). Nanosacle zero-valent iron (NZVI) and iron cross-linked alginate beads were also tested for phosphate removal using actual wastewater treatment plant effluent and animal feedlot runoff. The FCA beads could remove ~63% and ~77% phosphate from wastewater and feedlot runoff in 15 min, respectively. Bioavailability of phosphate was examined using algae and higher plants. Phosphate and iron bioavailability of the NZVI sorbed phosphate was examined by supplying spent particles (NZVI with sorbed phosphate) to Tyee Spinach (Spinacia oleracea) and algae (Selenastrum capricornutum). Results revealed that the phosphate was bioavailable for both the algae and spinach. Also, presence of the nanoparticles enhanced the algae growth and plant growth and increases in biomass and plant length were observed. Iron (from spent NZVI) was found to be bioavailable for spinach.
Identification and Characterization of Fibrous Zeolites in Western North Dakota
(North Dakota State University, 2012) Triplett, Jason
The fibrous zeolite mineral erionite is a concern due to its potential for causing lung disease in humans. Studies have shown that exposure to altered volcanic bedrock containing erionite may be the explanation for a high lung disease rate throughout regions of the world (Metintas et al., 1999). Erionite was reported by Forsman (1986) as occurring in tuffaceous rock units of the Arikaree Formation in the Killdeer Mountains of western North Dakota. Rock and soil samples were collected where zeolite minerals are known or suspected to be present including North and South Killdeer Mountains in Dunn County and West and East Rainy Buttes and White Butte in Slope County. Analysis and identification was carried out using XRD, SEM, and EMPA. Zeolitic material was confirmed in units for both North and South Killdeer Mountains. The chemical compositions of the fibers resulted in a majority being classified as offretite rather than erionite.
Ecological Complexity of Non-Native Species Impacts in Desert Aquatic Systems
(North Dakota State University, 2012) Henkanaththegedara, Sujan Maduranga
Without an adequate understanding of complex interactions between native and non-native species, management of invasive species can result in unforeseen detrimental impacts. I used both field and laboratory experiments to study reciprocal species interactions between the endangered Mohave tui chub (Siphateles bicolor mohavensis) and invasive western mosquitofish (Gambusia affinis). I also examined the impacts of both fish species on the aquatic invertebrate communities in desert springs. I demonstrate a case of intraguild predation (IGP) as a mechanism facilitating co-persistence of the endangered Mohave tui chub with invasive mosquitofish using field mesocosm experiments. In this case of IGP, adult tui chub prey on adult and juvenile mosquitofish, while adult mosquitofish prey on tui chub eggs and/or larvae. I conducted laboratory predation trials to assess if IGP was size-structured due to predator gape-limitation. I explored sex specific differences in gape-size limitation in mosquitofish, because mosquitofish are sexually dimorphic. Larval tui chubs had lower survival in the presence of female mosquitofish than in the presence of males. Reciprocally, male mosquitofish had lower survival than the females in the presence of Mohave tui chub. These results combined with vulnerability modeling supported that IGP in this system is size structured based on gape-size limitation. These results collectively suggest size-structured IGP may facilitate the co-persistence of these two fish species. My findings also suggest that mosquitofish may not be a limiting factor for the persistence of the endangered Mohave tui chub. Further, habitats currently harboring mosquitofish were considered as future refuge habitats for Mohave tui chub, a management option previously un-available. In addition to such reciprocal interactions between fish species, recently established fish populations may impact unique invertebrate communities. Mesocosm experiments with sympatric and allopatric populations of tui chub and mosquitofish showed negative impacts of both fish species on changes of invertebrate community structure. Specifically, fish caused population declines and, in some cases, extirpations of various invertebrate taxa. These results suggest important conservation implications of invasive fish as well as protected fish transplants into fishless desert springs. Overall my research emphasizes the complexity of ecological interactions between native and non-native fish species in desert aquatic systems.

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