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Community composition and nitrogen retention in an aridland wastewater treatment wetland

Description
City managers and policy makers are increasing looking to environmental systems to provide beneficial services for urban systems. Constructed wetland systems (CWS), highly managed and designed wetland ecosystems, are being utilized to remove pollution, particularly excess nitrogen (N), from treated wastewater. Various wetland process remove N from effluent, such as…

City managers and policy makers are increasing looking to environmental systems to provide beneficial services for urban systems. Constructed wetland systems (CWS), highly managed and designed wetland ecosystems, are being utilized to remove pollution, particularly excess nitrogen (N), from treated wastewater. Various wetland process remove N from effluent, such as denitrification, direct plant uptake, and soil accumulation. Emergent macrophytes provide direct uptake of N and improve conditions for microbially-mediated N processing. The role of different macrophytes species, however, is less understood and has primarily been examined in mesocosm and microcosm experiments and in mesic environments. I examined the effects of community composition on N removal and processing at the whole ecosystem scale in an aridland, constructed wetland (42 ha) through: 1) quantifying above- and belowground biomass and community composition from July 2011 \u2014 November 2012 using a non-destructive allometric technique, and; 2) quantifying macrophyte N content and direct macrophyte N uptake over the 2012 growing season. Average peak biomass in July 2011 & 2012 was 2,930 g dw/m2 and 2,340 g dw/m2, respectively. Typha spp. (Typha domingensis and Typha latifolia) comprised the majority (approximately 2/3) of live aboveground biomass throughout the sampling period. No statistically significant differences were observed in macrophyte N content among the six species present, with an overall average of 1.68% N in aboveground tissues and 1.29% N in belowground tissues. Per unit area of wetland, Typha spp. retained the most N (22 g/m2); total N retained by all species was 34 g/m2. System-wide direct plant N uptake was markedly lower than N input to the system and thus represented a small portion of system N processing. Soil accumulation of N also played a minor role, leaving denitrification as the likely process responsible for the majority of system N processing. Based on a literature review, macrophyte species composition likely influences denitrification through oxygen diffusion into soils and through the quality and quantity of carbon in leaf litter. While this study and the literature indicates Typha spp. may be the best species to promote wetland N processing, other considerations (e.g., bird habitat) and conditions (e.g., type of wastewater being treated) likely make mixed stands of macrophytes preferable in many applications. Additionally, this study demonstrated the importance of urban wetlands as scientific laboratories for scientists of all ages and as excellent stepping-off points for experiments of science-policy discourse.
ContributorsWeller, Nicholas Anton (Author) / Daniel L., Childers (Thesis director) / Grimm, Nancy (Committee member) / Turnbull, Laura (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / School of Public Affairs (Contributor) / Graduate College (Contributor)
Created2013-05
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The Campus Carry Controversy at University of Texas Austin: an American Debate

Description

An in depth look at the rhetoric behind the campus carry debate at the University of Texas at Austin. This thesis researched and examined primary sources from The Daily Texan and The Austin-American Statesman attempting to analyze what was at stake for both sides of the argument and what the…

An in depth look at the rhetoric behind the campus carry debate at the University of Texas at Austin. This thesis researched and examined primary sources from The Daily Texan and The Austin-American Statesman attempting to analyze what was at stake for both sides of the argument and what the most effective rhetorical tool was.
ContributorsBlumstein, Cory Joshua (Author) / Young, Alexander (Thesis director) / O'Flaherty, Katherine (Committee member) / School of Criminology and Criminal Justice (Contributor) / School of Public Affairs (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Documenting enhanced nitrogen removal in an aridland Constructed Treatment Wetland

Description

The rise in urban populations is encouraging cities to pursue sustainable water treatment services implementing constructed treatment wetlands (CTW). This is especially important in arid climates where water resources are scarce; however, research regarding aridland CTWs is limited. The Tres Rios CTW in Phoenix, Arizona, USA, presents the tradeoff between…

The rise in urban populations is encouraging cities to pursue sustainable water treatment services implementing constructed treatment wetlands (CTW). This is especially important in arid climates where water resources are scarce; however, research regarding aridland CTWs is limited. The Tres Rios CTW in Phoenix, Arizona, USA, presents the tradeoff between greater water loss and enhanced nitrogen (N) removal. Previous research has suggested that water loss due to transpiration is replaced by a phenomenon termed the Biological Tide. This trend has been documented since 2011 by combining transpiration values with a nitrogen budget. Calculations were made at both the marsh and whole-system scale. The purpose of this paper is to demonstrate how the Biological Tide enhances N uptake throughout the CTW. Results indicate that about half of the nitrogen taken up by the vegetated marsh is associated with new water entering the marsh via the Biological Tide with even higher values during warmer months. Furthermore, it is this phenomenon that enhances N uptake throughout the year, on average, by 25.9% for nitrite, 9.54% for nitrate, and 4.84% for ammonium at the whole-system scale and 95.5%, 147%, and 118% within the marsh. This paper demonstrates the Biological Tide’s significant impact on enhanced N removal in an aridland CTW.
ContributorsTreese, Sawyer Matthew (Author) / Childers, Daniel L. (Thesis director) / Grimm, Nancy (Committee member) / School of Geographical Sciences and Urban Planning (Contributor) / School of Sustainability (Contributor) / School of Public Affairs (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05

A God-Given Right: Exploring the Connection Between the “No Compromise” Gun Rights Movement and White Christian Nationalism

Description
The "no compromise" gun rights movement, which advocates against any form of gun control and the absolute right to keep and bear arms, and white Christian nationalism, a cultural framework built on the belief that Christianity should serve as the foundation of the American government, have both recently come to…

The "no compromise" gun rights movement, which advocates against any form of gun control and the absolute right to keep and bear arms, and white Christian nationalism, a cultural framework built on the belief that Christianity should serve as the foundation of the American government, have both recently come to the national political forefront. The connection between these two movements runs deep: white Christian nationalism informs the religious rhetoric of the "no compromise" movement. To understand why this is, the existing scholarship argues that white Christian nationalists advocate against gun control because they believe the Second Amendment is divinely inspired and that gun control does not address what they perceive to be a moral decline in the United States. However, these explanations are insufficient to fully grasp the inherent importance of guns and gun rights to white Christian nationalists. Therefore, I examine the specific roles that guns play in their worldview.
ContributorsMyers, Patrick (Author) / Young, Alexander (Thesis director) / Livingston, Lindsay (Committee member) / Barrett, The Honors College (Contributor) / School of Accountancy (Contributor)
Created2023-12