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- Creators: Barrett, The Honors College
Description
Microalgae represent a potential sustainable alternative for the enhancement and protection of agricultural crops. The dry biomass and cellular extracts of Scenedesmus dimorphus were applied as a biofertilizer, a foliar spray, and a seed primer to evaluate seed germination, plant growth, and crop yield of Roma tomato plants. The dry biomass was applied as a biofertilizer at 50 g and 100 g per plant, to evaluate its effects on plant development and crop yield. Biofertilizer treatments enhanced plant growth and led to greater crop (fruit) production. Timing of biofertilizer application proved to be of importance - earlier 50 g biofertilizer application resulted in greater plant growth. Scenedesmus dimorphus culture, growth medium, and different concentrations (1%, 5%, 10%, 25%, 50%, 75%, 100%) of aqueous cell extracts were used as seed primers to determine effects on germination. Seeds treated with Scenedesmus dimorphus culture and with extract concentrations higher than 50 % (0.75 g ml-1) triggered faster germination - 2 days earlier than the control group. Extract foliar sprays of 50 ml and 100 ml, were obtained and applied to tomato plants at various extract concentrations (10%, 25%, 50%, 75% and 100%). Plant height, flower development and number of branches were significantly enhanced with 50 % (7.5 g ml-1) extracts. Higher concentration sprays led to a decrease in growth. The extracts were further screened to assess potential antimicrobial activity against the bacterium Escherichia coli ATCC 25922, the fungi Candida albicans ATCC 90028 and Aspergillus brasiliensis ATCC 16404. No antimicrobial activity was observed from the microalga extracts on the selected microorganisms.
ContributorsGarcia-Gonzalez, Jesus (Author) / Sommerfeld, Milton (Thesis advisor) / Steele, Kelly (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2014
Description
For the past 30 years wildlife biologists have debated the need of pronghorn antelope (Antilocapra americana) to drink freestanding water (free water). Some have suggested that pronghorn may feed at night to increase preformed water (plant moisture) intake, thus decreasing their dependence on free water. Pronghorn diet composition and nutrient intake is integral to understanding water available to pronghorn through preformed and metabolic sources. The dual purpose of this study was to determine plant composition of pronghorn diets, and to examine whether night feeding provides a water allocation advantage by testing for differences between day and night and modeling free water requirements during biologically critical seasons and years of different precipitation. I determined species composition, selected nutrients, and moisture content of American pronghorn diets on Perry Mesa, Arizona in March, May, June and August of 2008 and 2009. I used microhistological analysis of fecal samples to determine percent plant composition of pronghorn diets. I used forage samples to evaluate the nutrient composition of those diets for moisture, crude protein and structural carbohydrates, and to calculate metabolic water. I used calculations proposed by Fox et al. (2000) to model free water requirements and modified the equations to reflect increased requirements for lactation. Diet analysis revealed that pronghorn used between 67% and 99% forbs and suggested fair range conditions. Preformed water was not significantly different between night and day. Night feeding appeared to be of marginal advantage, providing an average potential 9% preformed water increase in 2008, and 3% in 2009. The model indicated that neither male nor female pronghorn could meet their water requirements from preformed and metabolic water during any time period, season or year. The average free water requirements for females ranged from 0.67 L/animal/day (SE 0.06) in March, 2008 to 3.12 L/animal/day (SE 0.02) in June, 2009. The model showed that American pronghorn on Perry Mesa require access to free water during biological stress periods.
ContributorsTluczek, Melanie (Author) / Miller, William H. (Thesis advisor) / Brown, David E. (Committee member) / Steele, Kelly (Committee member) / Arizona State University (Publisher)
Created2012
Description
This paper explores the relationship between wildfire management and the consideration of ecological and environmental concerns in Arizona. To get a proper perspective on the current state of wildfire management in Arizona, information on two wildfire management programs, the Four Forests Restoration Initiative and FireScape, was researched and analyzed, as well as contemporary fire policy, a history of wildfire in Arizona, and two recent fires in Sedona, AZ. The two fires in Sedona, the Brins Fire of 2006 and the Slide Fire of 2014, act as a focal point for this ecological management transition, as even within an 8-year period, we can see the different ways the two fires were managed and the transition to a greater ecological importance in management strategies. These all came together to give a full spectrum for the factors that have led to more ecologically-prominent wildfire management strategies in Arizona.
ContributorsGeorge-Sills, Dylan (Author) / Pyne, Stephen (Thesis director) / Hirt, Paul (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Sustainability (Contributor)
Created2015-05
Description
Water is the main driver of net primary productivity (NPP) in arid ecosystems, followed by nitrogen and phosphorous. Precipitation is the primary factor in determining water availability to plants, but other factors such as surface rocks could also have an impact. Surface rocks may positively affect water availability by preventing evaporation from soil, but at higher densities, surface rocks may also have a negative impact on water availability by limiting water infiltration or light availability. However, the direct relationship between rock cover and aboveground net primary productivity (ANPP), a proxy for NPP, is not well understood. In this research we explore the relationship between rock cover, ANPP, and soil nutrient availability. We conducted a rock cover survey on long-term fertilized plots at fifteen sites in the Sonoran Desert and used 4 years of data from annual plant biomass surveys to determine the relationship between peak plant biomass and surface rock cover. We performed factorial ANCOVA to assess the relationship among annual plant biomass, surface rocks, precipitation, and fertilization treatment. Overall we found that precipitation, nutrients, and rock cover influence growth of Sonoran Desert annual plants. Rock cover had an overall negative relationship with annual plant biomass, but did not show a consistent pattern of significance over four years of study and with varying average winter precipitation.
ContributorsShaw, Julea Anne (Author) / Hall, Sharon (Thesis director) / Sala, Osvaldo (Committee member) / Cook, Elizabeth (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Is it possible to treat the mouth as a natural environment, and determine new methods to keep the microbiome in check? The need for biodiversity in health may suggest that every species carries out a specific function that is required to maintain equilibrium and homeostasis within the oral cavity. Furthermore, the relationship between the microbiome and its host is mutually beneficial because the host is providing microbes with an environment in which they can flourish and, in turn, keep their host healthy. Reviewing examples of larger scale environmental shifts could provide a window by which scientists can make hypotheses. Certain medications and healthcare treatments have been proven to cause xerostomia. This disorder is characterized by a dry mouth, and known to be associated with a change in the composition, and reduction, of saliva. Two case studies performed by Bardow et al, and Leal et al, tested and studied the relationships of certain medications and confirmed their side effects on the salivary glands [2,3]. Their results confirmed a relationship between specific medicines, and the correlating complaints of xerostomia. In addition, Vissink et al conducted case studies that helped to further identify how radiotherapy causes hyposalivation of the salivary glands [4]. Specifically patients that have been diagnosed with oral cancer, and are treated by radiotherapy, have been diagnosed with xerostomia. As stated prior, studies have shown that patients having an ecologically balanced and diverse microbiome tend to have healthier mouths. The oral cavity is like any biome, consisting of commensalism within itself and mutualism with its host. Due to the decreased salivary output, caused by xerostomia, increased parasitic bacteria build up within the oral cavity thus causing dental disease. Every human body contains a personalized microbiome that is essential to maintaining health but capable of eliciting disease. The Human Oral Microbiomics Database (HOMD) is a set of reference 16S rRNA gene sequences. These are then used to define individual human oral taxa. By conducting metagenomic experiments at the molecular and cellular level, scientists can identify and label micro species that inhabit the mouth during parasitic outbreaks or a shifting of the microbiome. Because the HOMD is incomplete, so is our ability to cure, or prevent, oral disease. The purpose of the thesis is to research what is known about xerostomia and its effects on the complex microbiome of the oral cavity. It is important that researchers determine whether this particular perspective is worth considering. In addition, the goal is to create novel experiments for treatment and prevention of dental diseases.
ContributorsHalcomb, Michael Jordan (Author) / Chen, Qiang (Thesis director) / Steele, Kelly (Committee member) / Barrett, The Honors College (Contributor) / College of Letters and Sciences (Contributor)
Created2015-05
Description
Defines the concept of the arcology as conceived by architect Paolo Soleri. Arcology combines "architecture" and "ecology" and explores a visionary notion of a self-contained urban community that has agricultural, commercial, and residential facilities under one roof. Two real-world examples of these projects are explored: Arcosanti, AZ and Masdar City, Abu Dhabi, UAE. Key aspects of the arcology that could be applied to an existing urban fabric are identified, such as urban design fostering social interaction, reduction of automobile dependency, and a development pattern that combats sprawl. Through interviews with local representatives, a holistic approach to applying arcology concepts to the Phoenix Metro Area is devised.
ContributorsSpencer, Sarah Anne (Author) / Manuel-Navarrete, David (Thesis director) / Salon, Deborah (Committee member) / Barrett, The Honors College (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / School of Sustainability (Contributor)
Created2015-05
Description
In today's world, critical thinking and using a systems approach to problem solving are skills that are far too rare. In the age of information, the truth has become muddled by "fake news" and a constant barrage of exaggerations or blatant falsehoods. Without critical thinking skills, "many members of our society do not command the scientific literacy necessary to address important societal issues and concerns" (NCES 2012, p.11). Additionally, far too many people are incapable of thinking long term and understanding how their actions affect others. Because of this shortsightedness our world is facing one of its biggest ecological crises \u2014 global warming confounded by overpopulation and overconsumption. Now, more than ever, it is critical "for our young people to have a basic understanding of the relevant scientific ideas, technologies and ethical issues and powers of reasoning, to be prepared to face these issues" (Harlen et al., 2015). I believe that investigating innovative ways to teach ecology could be an important step to accomplishing this. Learning to think like a scientist forces people to rely on facts, follow similar protocols to deduce these facts, and be able to think critically about misleading events. More specifically, ecology education will allow people to develop those skills while also learning about team work, open-mindedness, and their environment. Ecology is defined as "the branch of biology that deals with the relations of organisms to one another and to their physical surroundings" (Dictionary.com, 2018). It is clear that this subcategory of science could act as a powerful introduction to the scientific world and how we relate to it. Its introduction at a young age has the potential to create a generation of conscientious and curious lifelong learners. In an attempt to support effective ways to teach ecology, I developed an educational unit and applied it in different educational contexts. My target audience was elementary aged students and I tested this unit with children in Phoenix Metropolitan Area afterschool programs. I taught core concepts of ecology \u2014 the water cycle, the sun's energy, plants and photosynthesis, and food webs \u2014in a sequence of lesson plans that build upon each other. Finally, I determined the appropriate age group and setting for these lesson plans through research and in-class observations. In this document, I explain the process I went through in developing my lesson plans, why I felt compelled to make them, and my experiences in implementing them.
ContributorsVotaw, Alexandra Lindsay (Author) / Larson, Kelli (Thesis director) / Herrmann, Lisa (Committee member) / York, Abigail (Committee member) / School of Art (Contributor) / The Design School (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
As threats to Earth's biodiversity continue to evolve, an effective methodology to predict such threats is crucial to ensure the survival of living species. Organizations like the International Union for Conservation of Nature (IUCN) monitor the Earth's environmental networks to preserve the sanctity of terrestrial and marine life. The IUCN Red List of Threatened Species informs the conservation activities of governments as a world standard of species' risks of extinction. However, the IUCN's current methodology is, in some ways, inefficient given the immense volume of Earth's species and the laboriousness of its species' risk classification process. IUCN assessors can take years to classify a species' extinction risk, even as that species continues to decline. Therefore, to supplement the IUCN's classification process and thus bolster conservationist efforts for threatened species, a Random Forest model was constructed, trained on a group of fish species previously classified by the IUCN Red List. This Random Forest model both validates the IUCN Red List's classification method and offers a highly efficient, supplemental classification method for species' extinction risk. In addition, this Random Forest model is applicable to species with deficient data, which the IUCN Red List is otherwise unable to classify, thus engendering conservationist efforts for previously obscure species. Although this Random Forest model is built specifically for the trained fish species (Sparidae), the methodology can and should be extended to additional species.
ContributorsWoodyard, Megan (Author) / Broatch, Jennifer (Thesis director) / Polidoro, Beth (Committee member) / Mancenido, Michelle (Committee member) / School of Humanities, Arts, and Cultural Studies (Contributor) / School of Mathematical and Natural Sciences (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Peatlands are a type of wetlands where the rate of accumulation of organic matter exceed the rate of decomposition and have accumulated more than 30 cm of peat (Joosten and Clark, 2002). Peatlands store approximately 30% of all terrestrial carbon as recalcitrant peat, partially decomposed plant and microbial biomass, while simultaneously producing almost 40% of the globally emitted methane (Schmidt et al., 2016), making peatlands an important component of the carbon budgets. Published research indicates that the efficiency of carbon usage among microbial communities can determine the soil-carbon response to rising temperatures (Allison et al. 2010). By determining carbon consumption in peatland soils, total community respiration response, and community structure change with additions, models of carbon use efficiency in permafrost peatlands will be well-informed and have a better understanding of how the peatlands will respond to, and utilize, increased availability of carbon compounds due to the melting permafrost. To do this, we will sequence Lutose deep core samples to observe baseline microbial community structure at different depths and different age-gradients, construct substrate incubations of glucose and propionate and observe community respiration response via a gas chromatography flame ionization detector, track the glucose and propionate additions with high-performance liquid chromatography (HPLC), and sequence the samples once more to determine if there was a deviation from the initial community structure obtained prior to the incubations. We found that our initial sequencing data was supported by previous work (Lin et al., 2014), however we were unable to sequence samples post-incubation due to time constraints. In this sequencing analysis we found that the strongest variable that made samples biologically similar was the age-gradient site in which they were extracted. We found that the group with glucose additions produced the most carbon dioxide compared with the other treatments, but was not the treatment that dominated the production of methane. Finally, in the HPLC samples that were analyzed, we found that glucose is likely forming the most by-product accumulation from mass balance calculations, while propionate is likely forming the least. Future experimentation should focus on the shortcomings of this experiment. Further analysis of 16S rRNA sequencing data from after the incubations should be analyzed to determine the change in microbial community structure throughout the experiment. Furthermore, HPLC analysis for the several samples need to be done and followed up with mass balance to determine where the added glucose and propionate are being allocated within the soil. Once these pieces of the puzzle are put into place, our original question of how the microbial community structure changes at different depths and age-gradients within permafrost peatlands will be conclusively answered.
ContributorsFrese, Alexander Nicholas (Author) / Cadillo-Quiroz, Hinsby (Thesis director) / van Paassen, Leon (Committee member) / Sarno, Analissa (Committee member) / School of Life Sciences (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Ephemeral and intermittent streams are valuable sources of surface water support in the arid ecosystems of the Southwestern United States. These streams account for over 80% of the streams in the American Southwest and their importance has been indicated in many studies. Ephemeral and intermittent streams support a wide range of plant and animal species in both continuous and episodic fashions. This study aimed to gain a better understanding of the relationship between streamflow permanence and patterns of biomass and secondary production of the riparian fauna these ecosystems support. This was accomplished through a yearlong survey in the Huachuca Mountains of Southeastern, Arizona where macroinvertebrates were collected at various sites along a gradient of streamflow permanence before, during, and after the three month monsoon season that supplies most of the annual rainfall in this region. The results of my surveys indicate that 1) Sites characterized by low streamflow permanence were more responsive to changes in precipitation than sites characterized by relatively high streamflow permanence 2) In ephemeral streams, there is a significant peak in terrestrial macroinvertebrate production and biomass both during and after the monsoon season 3) streamflow permanence may convey consistent but not exceptional secondary production whereas seasonality in rainfall may convey exceptional but episodic secondary production—more so in sites where streamflow is not consistent.
ContributorsMcCartin, Michael Patrick (Author) / Sabo, John (Thesis director) / Stromberg, Juliet (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05