Matching Items (4)
Description
Utilizing both 16S and 18S rRNA sequencing alongside energetic calculations from geochemical measurements offers a bridged perspective of prokaryotic and eukaryotic community diversities and their relationships to geochemical diversity. Yellowstone National Park hot spring outflows from varied geochemical compositions, ranging in pH from < 2 to > 9 and in temperature from < 30°C to > 90°C, were sampled across the photosynthetic fringe, a transition in these outflows from exclusively chemosynthetic microbial communities to those that include photosynthesis. Illumina sequencing was performed to document the diversity of both prokaryotes and eukaryotes above, at, and below the photosynthetic fringe of twelve hot spring systems. Additionally, field measurements of dissolved oxygen, ferrous iron, and total sulfide were combined with laboratory analyses of sulfate, nitrate, total ammonium, dissolved inorganic carbon, dissolved methane, dissolved hydrogen, and dissolved carbon monoxide were used to calculate the available energy from 58 potential metabolisms. Results were ranked to identify those that yield the most energy according to the geochemical conditions of each system. Of the 46 samples taken across twelve systems, all showed the greatest energy yields using oxygen as the main electron acceptor, followed by nitrate. On the other hand, ammonium or ammonia, depending on pH, showed the greatest energy yields as an electron donor, followed by H2S or HS-. While some sequenced taxa reflect potential biotic participants in the sulfur cycle of these hot spring systems, many sample locations that yield the most energy from ammonium/ammonia oxidation have low relative abundances of known ammonium/ammonia oxidizers, indicating potentially untapped sources of chemotrophic energy or perhaps poorly understood metabolic capabilities of cultured chemotrophs.
ContributorsRomero, Joseph Thomas (Author) / Shock, Everett L (Thesis advisor) / Cadillo-Quiroz, Hinsby (Committee member) / Till, Christy B. (Committee member) / Arizona State University (Publisher)
Created2018
Description
There is a need in the ecology literature to have a discussion about the fundamental theories from which population dynamics arises. Ad hoc model development is not uncommon in the field often as a result of a need to publish rapidly and frequently. Ecologists and statisticians like Robert J. Steidl and Kenneth P Burnham have called for a more deliberative approach they call "hard thinking". For example, the phenomena of population growth can be captured by almost any sigmoid function. The question of which sigmoid function best explains a data set cannot be answered meaningfully by statistical regression since that can only speak to the validity of the shape. There is a need to revisit enzyme kinetics and ecological stoichiometry to properly justify basal model selection in ecology. This dissertation derives several common population growth models from a generalized equation. The mechanistic validity of these models in different contexts is explored through a kinetic lens. The behavioral kinetic framework is then put to the test by examining a set of biologically plausible growth models against the 1968-1995 elk population count data for northern Yellowstone. Using only this count data, the novel Monod-Holling growth model was able to accurately predict minimum viable population and life expectancy despite both being exogenous to the model and data set. Lastly, the elk/wolf data from Yellowstone was used to compare the validity of the Rosenzweig-MacArthur and Arditi-Ginzburg models. They both were derived from a more general model which included both predator and prey mediated steps. The Arditi-Ginzburg model was able to fit the training data better, but only the Rosenzweig-MacArthur model matched the validation data. Accounting for animal sexual behavior allowed for the creation of the Monod-Holling model which is just as simple as the logistic differential equation but provides greater insights for conservation purposes. Explicitly acknowledging the ethology of wolf predation helps explain the differences in predictive performances by the best fit Rosenzweig-MacArthur and Arditi-Ginzburg models. The behavioral kinetic framework has proven to be a useful tool, and it has the ability to provide even further insights going forward.
ContributorsPringle, Jack Andrew McCracken (Author) / Anderies, John M (Thesis advisor) / Kuang, Yang (Committee member) / Milner, Fabio (Committee member) / Arizona State University (Publisher)
Created2022
Description
I present for the first time a broad-scale assessment of dissolved organic matter in the continental hot springs of Yellowstone National Park. The concentration of dissolved organic carbon in hot springs is highly variable, but demonstrates distinct trends with the geochemical composition of springs. The dissolved organic carbon concentrations are lowest in the hottest, most deeply sourced hot springs. Mixing of hydrothermal fluids with surface waters or reaction with buried sedimentary organic matter is typically indicated by increased dissolved organic carbon concentrations. I assessed the bulk composition of organic matter through fluorescence analysis that demonstrated different fluorescent components associated with terrestrial organic matter, microbial organic matter, and several novel fluorescent signatures unique to hot springs. One novel fluorescence signature is observed exclusively in acidic hot springs, and it is likely an end product of thermally-altered sedimentary organic matter. This acid-spring component precipitates out of solution under neutral or alkaline conditions and characterization of the precipitate revealed evidence for a highly condensed aromatic structure. This acid-spring component serves as a reliable tracer of acidic, hot water that has cycled through the subsurface. Overall, dissolved organic carbon concentrations and fluorescent features correlate with the inorganic indicators traditionally used to infer spring fluid mixing in the subsurface. Further, the fluorescence information reveals subtle differences in mixing between fluid phases that are not distinguishable through classic inorganic indicator species. My work assessing dissolved organic carbon in the Yellowstone National Park hot springs reveals that the organic matter in hydrothermal systems is different from that found in surface waters, and that the concentration and composition of hot spring dissolved organic matter reflects the subsurface geochemical and hydrological environment.
ContributorsNye, Joshua (Author) / Hartnett, Hilairy E (Thesis advisor) / Shock, Everett L (Committee member) / Jones, Anne K (Committee member) / Arizona State University (Publisher)
Created2020
Description
In “The Trouble of Wilderness,” William Cronon (1995) states the concept of wilderness, historically, is based on the romanticized ideal of the “untamed” frontier that influenced the American expansion ideals in the late 1800s and early 1900s, including the initial conservation movement. This idea of wilderness is defined by “empty” lands that needed to be utilized by the civilized Anglo-Americans, or lands that needed to be preserved from human alterations. Wilderness was separate from humans and, therefore, was also thought to be land that had been unaltered by human touch. The disappearing frontier was being turned into farmlands and civilization, so the Anglo-Americans, the ones who culturally viewed undeveloped land as a place for recreation, wished to save the ‘wilderness’ that was not yet being used. But as will be discussed it was in fact being used just not by the Anglo-Americans. This wilderness that they were trying to preserve became the national parks, such as Yellowstone and Yosemite. Under this rationale, Indigenous peoples were forced off the land to create the illusion of these places fitting this romanticized idea of wilderness. This essay examines the national parks in context of this concept of wilderness being free from humans and how national parks rationalized the removal of Indigenous people from these “wild” lands by using this concept of wilderness. Specifically, it uses the history of Yellowstone and Yosemite parks, which are some of the first parks to enter the National Park System, as sites of understanding how the idea wilderness was conceptualized by the American government during the late 1800s as places that are separate from humans. This essay argues that these ideals are based on racist and xenophobic approaches that the early United States government used in regards to relationships with Indigenous people. To discuss these ideas, this paper will examine the language used in early government documents regarding the policies of the national parks along with art and writings from this time period to show how the public and government viewed these national parks and the Indigenous people in the surrounding areas. Particularly, this paper will consider the original documents that established the national parks and the language that was used in these documents. It will then compare these policies from the origins of the national parks to the policies in place now regarding Indigenous people, such as the reparations that are trying to be made in these areas.
ContributorsSease, Emma Lynne (Author) / Richter, Jennifer (Thesis director) / Minteer, Ben (Committee member) / School of Life Sciences (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05