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Description
Volcanic devolatilization is one of the major processes in the global nitrogen cycle. Past studies have often estimated the magnitude of this flux using volcanic emission measurements, which are limited to currently active systems and sensitive to atmospheric contamination. A different methodological approach requires appropriate analytical parameters for nitrogen analysis

Volcanic devolatilization is one of the major processes in the global nitrogen cycle. Past studies have often estimated the magnitude of this flux using volcanic emission measurements, which are limited to currently active systems and sensitive to atmospheric contamination. A different methodological approach requires appropriate analytical parameters for nitrogen analysis in silicate glasses by secondary ion mass spectrometry (SIMS), which have not yet been established. To this end, we analyze various ion implanted basaltic and rhyolitic glasses by SIMS. We demonstrate that water content significantly affects the ion yields of 14N+ and 14N16O−, as well as the background intensity of 14N+ and 12C+. Application of implant-derived calibrations to natural samples provide the first reported concentrations of nitrogen in melt inclusions. These measurements are from samples from the Bishop Tuff in California, the Huckleberry Ridge Tuff of the Yellowstone Volcanic Center, and material from the Okaia and Oruanui eruptions in the Taupo Volcanic Center. In all studied material, we find maximum nitrogen contents of less than 45 ppm and that nitrogen concentration varies positively with CO2 concentration, which is interpreted to reflect partial degassing trend. Using the maximum measured nitrogen contents for each eruption, we find that the Bishop released >3.6 x 1013 g of nitrogen, the Huckleberry Ridge released >1.3 x 1014 g, the Okaia released >1.1 x 1011 g of nitrogen, the Oruanui released >4.7 x 1013 g of nitrogen. Simple calculations suggest that with concentrations such as these, rhyolitic eruptions may ephemerally increase the nitrogen flux to the atmosphere, but are insignificant compared to the 4 x 1021 g of nitrogen stored in the atmosphere.
ContributorsRegier, Margo Elaine (Author) / Hervig, Richard L (Thesis advisor) / Roggensack, Kurt (Committee member) / Till, Christy B. (Committee member) / Arizona State University (Publisher)
Created2016
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Description
Nutrient rich agricultural runoff is a major source of phosphorus (P) and nitrogen (N) loading to surface waters, resulting in eutrophication and harmful algal blooms. The most effective nutrient removal technologies often have cost, land, or operational requirements that limits use in the decentralized areas that need it most. This

Nutrient rich agricultural runoff is a major source of phosphorus (P) and nitrogen (N) loading to surface waters, resulting in eutrophication and harmful algal blooms. The most effective nutrient removal technologies often have cost, land, or operational requirements that limits use in the decentralized areas that need it most. This dissertation investigated combined physical-chemical and microbiological technologies for combined P and N removal from nonpoint sources. Chapter 2 investigated the combination of basic oxygen furnace (BOF) steel slag and woody mulch for P removal by mineral precipitation and N removal by microbial denitrification. When combined with mulch in column experiments, slag with high fines content achieved complete P removal under unsaturated conditions. Batch experiments showed that microbial denitrification occurred under the highly alkaline conditions created by steel slag, but the timescale differential between P and N removal was a critical barrier to combining these treatment technologies. Chapter 3 evaluated a field-scale slag filter to treat agricultural tile drainage and lab-scale column experiments to provide insight on field conditions that impacted P removal. Increases in alkalinity had negative influences on P removal through inhibition of P mineral precipitation by BOF slag, while blast furnace (BF) steel slag was less impacted by alkalinity due to primarily adsorptive P removal. Regeneration strategies were identified based on water quality and slag type.Chapters 4 and 5 explored biological ion exchange (BIEX) as an option for addressing the timescale offset identified in Chapter 1. In Chapter 4 columns fed with dissolved organic matter (DOM) were not regenerated and over 50% DOM removal was observed, with the primary mechanism of removal identified as secondary ion exchange (SIEX) between sulfate and DOM fractions with high affinities for ion exchange. Chapter 5 aimed to expand BIEX to N treatment through batch denitrification and adsorption experiments, which revealed a positive relationship between molecular weight of organic molecules and their ability to displace nitrate. This work shows that by having an improved understanding of impacted water characteristics, the information presented in this work can be used to select and implement effective treatment technologies for decentralized areas.
ContributorsEdgar, Michael Garrett (Author) / Boyer, Treavor H (Thesis advisor) / Hamdan, Nasser (Committee member) / Delgado, Anca (Committee member) / Arizona State University (Publisher)
Created2022
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Description
A novel technique for measuring heavy trace elements in geologic materials with secondary ion mass spectrometry (SIMS) is presented. This technique combines moderate levels of mass resolving power (MRP) with energy filtering in order to remove molecular ion interferences while maintaining enough sensitivity to measure trace elements. The technique was

A novel technique for measuring heavy trace elements in geologic materials with secondary ion mass spectrometry (SIMS) is presented. This technique combines moderate levels of mass resolving power (MRP) with energy filtering in order to remove molecular ion interferences while maintaining enough sensitivity to measure trace elements. The technique was evaluated by measuring a set of heavy chalcophilic elements in two sets of doped glasses similar in composition to rhyolites and basalts, respectively. The normalized count rates of Cu, As, Se, Br, and Te were plotted against concentrations to test that the signal increased linearly with concentration. The signal from any residual molecular ion interferences (e.g. ²⁹Si³⁰Si¹⁶O on ⁷⁵As) represented apparent concentrations ≤ 1 μg/g for most of the chalcophiles in rhyolitic matrices and between 1 and 10 μg/g in basaltic compositions. This technique was then applied to two suites of melt inclusions from the Bandelier Tuff: Ti-rich, primitive and Ti-poor, evolved rhyolitic compositions. The results showed that Ti-rich inclusions contained ~30 μg/g Cu and ~3 μg/g As while the Ti-poor inclusions contained near background Cu and ~6 μg/g As. Additionally, two of the Ti-rich inclusions contained > 5 μg/g of Sb and Te, well above background. Other elements were at or near background. This suggests certain chalcophilic elements may be helpful in unraveling processes relating to diversity of magma sources in large eruptions. Additionally, an unrelated experiment is presented demonstrating changes in the matrix effect on SIMS counts when normalizing against ³⁰Si⁺ versus ²⁸Si²⁺. If one uses doubly charged silicon as a reference, (common when using large-geometry SIMS instruments to study the light elements Li - C) it is important that the standards closely match the major element chemistry of the unknown.
ContributorsCarlson, Eric Norton (Author) / Hervig, Richard L (Thesis advisor) / Roggensack, Kurt (Committee member) / Burt, Donald M (Committee member) / Arizona State University (Publisher)
Created2021