Matching Items (5)
Filtering by
- All Subjects: Environmental science
- Creators: Penton, Christopher
- Creators: Sabo, John L
- Status: Published
Description
Sexually transmitted diseases like gonorrhea and chlamydia, standardly treated with antibiotics, produce over 1.2 million cases annually in the emergency department (Jenkins et al., 2013). To determine a need for antibiotics, hospital labs utilize bacterial cultures to isolate and identify possible pathogens. Unfortunately, this technique can take up to 72 hours, leading to several physicians presumptively treating patients based solely on history and physical presentation. With vague standards for diagnosis and a high percentage of asymptomatic carriers, several patients undergo two scenarios; over- or under-treatment. These two scenarios can lead to consequences like unnecessary exposure to antibiotics and development of secondary conditions (for example: pelvic inflammatory disease, infertility, etc.). This presents a need for a laboratory technique that can provide reliable results in an efficient matter. The viability of DNA-based chip targeted for C. trachomatis, N. gonorrhoeae, and other pathogens of interest were evaluated. The DNA-based chip presented several advantages as it can be easily integrated as a routine test given the process is already well-known, is customizable and able to target multiple pathogens within a single test and has the potential to return results within a few hours as opposed to days. As such, implementation of a DNA-based chip as a diagnostic tool is a timely and potentially impactful investigation.
ContributorsCharoenmins, Patherica (Author) / Penton, Christopher (Thesis director) / Moore, Marianne (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Precision agriculture (PA) integrating information technology arouses broad interests and has been extensively studied to increase crop production and quality. Sensor probe technology, as one of the PA technologies, provides people with accurate real-time data, which has become an essential part of precision agriculture. Herein a novel microbial sensor probe (MiProbE) is applied to monitor and study the growth of tomatoes (Solanum lycopersicum L.) in real-time at germination and seedling stages. The result showed the raw Miprobe signals present day/night cycles. Alginate-coated probes effectively avoided signal response failure and were more sensitive to the treatments than uncoated probes. The probe signals from successfully germinated tomato seeds and non-germinated seeds were different, and the signal curve of the probe was closely related to the growth conditions of tomato seedlings. Specifically, the rising period of the probe signals coincided with the normal growth period of tomato seedlings. All probes exhibited sudden increases in signal strength after nutrient treatments; however, subsequent probe signals behaved differently: algae extract-treated probe signals maintained a high strength after the treatments; chemical fertilizer-treated probe signals decreased earlier after the treatments; chemical fertilizers and algae extract-treated probe signals also maintained a higher strength after the treatments. Moreover, the relationship between ash-free dry weight and the signal curve indicated that the signal strength positively correlates with the dry weight, although other biological activities can affect the probe signal at the same time. Further study is still needed to investigate the relationship between plant biomass and Miprobe signal.
ContributorsQi, Deyang (Author) / Weiss, Taylor (Thesis advisor) / Penton, Christopher (Committee member) / Park, Yujin (Committee member) / Arizona State University (Publisher)
Created2021
Description
Stressors to marine environments are predicted to increase and affect the well-being of marine ecosystems and coastal communities. Marine protected areas (MPAs) are one most widely implemented interventions for marine stressors. Despite the implementation of thousands of protected areas worldwide, people are still striving to understand their dynamics as they vary in their efficacy and many MPAs have not met their objectives. Additionally, those that have often fail to protect the ecosystem services and cultural values necessary for human community health. Thus, research has expanded to include analyses of the human and social dimensions that may limit their effectiveness. This dissertation explores the role of community engagement in marine protected areas and perceptions of environmental changes in coastal communities. Currently, existing research on the roles of community engagement in marine conservation interventions is limited, particularly in the island-states of the Caribbean region. This dissertation contains a review of the literature to understand the nuances of community engagement in relation to MPAs. Through the review, it was determined that primary forms of engagement are interviews and surveys, and respondents primarily included businesses, community members, fishers, and resource users. To better understand the perceptions and practices on-the-ground, key informants were interviewed across the Caribbean. There are strong desires to conduct community engagement for innumerable benefits, but there are barriers that some participants have overcome. Sharing information between MPA sites offers an opportunity to effectively engage community members. For the local case study, Charlotteville, Trinidad and Tobago, a small, coastal fishing town in the northeast region of Tobago was selected to understand the role of perceptions of environmental changes. There were strong ties of environmental and social changes, with an emphasis on the impacts of environmental stressors to human health. The heterogeneity and diversity of responses in this chapter highlight the need to consider who is engaged in community engagement activities.
ContributorsBernard, Miranda Lynn (Author) / Gerber, Leah (Thesis advisor) / Buzinde, Christine (Committee member) / Schoon, Michael (Committee member) / Kittinger, Jack (Committee member) / Cheng, Samantha (Committee member) / Arizona State University (Publisher)
Created2021
Assessing the Response of Macroinvertebrate Communities to River Flow Dynamics in the Sonoran Desert
Description
Climate change is causing hydrologic intensification globally by increasing both the frequency and magnitude of floods and droughts. While environmental variation is a key regulator at all levels of ecological organization, such changes to the hydrological cycle that are beyond the normal range of variability can have strong impacts on stream and riparian ecosystems within sensitive landscapes, such as the American Southwest. The main objective of this study was to investigate how anomalous hydrologic variability influences macroinvertebrate communities in desert streams. I studied seasonal changes in aquatic macroinvertebrate abundances in eleven streams that encompass a hydrologic gradient across Arizona’s Sonoran Desert. This analysis was coupled with the quantification and assessment of stochastic hydrology to determine influences of flow regimes and discrete events on invertebrate community composition. I found high community variability within sites, illustrated by seasonal measures of beta diversity and nonmetric multidimensional scaling (NMDS) plots. I observed notable patterns of NMDS data points when invertebrate abundances were summarized by summer versus winter surveys. These results suggest that there is a difference within the communities between summer and winter seasons, irrespective of differences in site hydroclimate. Estimates of beta diversity were the best metric for summarizing and comparing diversity among sites, compared to richness difference and replacement. Seasonal measures of beta diversity either increased, decreased, or stayed constant across the study period, further demonstrating the high variation within and among study sites. Regime shifts, summarized by regime shift frequency (RSF) and mean net annual anomaly (NAA), and anomalous events, summarized by the power of blue noise (Maximum Blue Noise), were the best predictors of macroinvertebrate diversity, and thus should be more widely applied to ecological data. These results suggest that future studies of community composition in freshwater systems should focus on understanding the cause of variation in biodiversity gradients. This study highlights the importance of considering both flow regimes and discrete anomalous events when studying spatial and temporal variation in stream communities.
ContributorsSainz, Ruby (Author) / Sabo, John L (Thesis advisor) / Grimm, Nancy (Committee member) / Stampoulis, Dimitrios (Committee member) / Arizona State University (Publisher)
Created2021
Description
Primary producers, from algae to trees, play a pivotal role in community structure and ecosystem function. Primary producers vary broadly in their functional traits (i.e., morphological, physiological, biochemical, and behavioral characteristics), which determine how they respond to stimuli and affect ecosystem properties. Functional traits provide a mechanistic link between environmental conditions, community structure, and ecosystem function. With climate change altering environmental conditions, understanding this mechanistic link is essential for predicting future community structure and ecosystem function. Competitive interactions and trait values in primary producers are often context dependent, whereby changes in environmental conditions and resources alter relationships between species and ecosystem processes. Well-established paradigms concerning how species in a community respond to each other and to environmental conditions may need to be re-evaluated in light of these environmental changes, particularly in highly variable systems. In this dissertation, I examine the role of primary producer functional traits on community structure and ecosystem function. Specifically, I test a conceptual framework that incorporates response traits, effect traits, and their interaction, in affecting primary producer communities and ecosystem function across different aquatic systems. First, I identified species-specific responses to intensifying hydrologic stressors important in controlling wetland plant community composition over time in an aridland stream. Second, I found that effect traits of submerged and emergent vegetation explained differences in ecosystem metabolism and carbon dynamics among permafrost mire thaw ponds. Next, I examined response-effect trait interactions by comparing two dominant wetland plant species over a water-stress gradient, finding that responses to changes in hydrology (i.e., altered tissue chemistry) in turn affect ecosystem processes (i.e., subsurface CO2 concentration). Finally, I demonstrate how indirect effects of diatom functional traits on water chemistry and ecosystem metabolism help explain disconnects between resource availability and productivity in the Colorado River. By expanding my understanding of how metabolic processes and carbon cycling in aquatic ecosystems vary across gradients in hydrology, vegetation, and organic matter, I contributed to my understanding of how communities influence ecosystem processes. A response-effect trait approach to understanding communities and ecosystems undergoing change may aid in predicting and mitigating the repercussions of future climate change.
ContributorsLauck, Marina Diane (Author) / Grimm, Nancy B (Thesis advisor) / Appling, Alison P (Committee member) / Childers, Dan E (Committee member) / Sabo, John L (Committee member) / Arizona State University (Publisher)
Created2022