Ecology and Evolutionary Biology Commons^™

Monitoring Photosynthetic Activity Using In Vivo Chlorophyll A Fluorescence In Microalgae And Cyanobacteria Biofilms In The Nerja Cave (Malaga, Spain), Yolanda Del Rosal, Juan Muñoz-Fernández, Paula S.M. Celis-Plá, Mariona Hernández-Mariné, Félix Álvarez-Gómez, Salvador Merino, Félix L. Figueroa

International Journal of Speleology

The characterization of the most common photosynthetic biofilms in the Nerja Cave by the continuous monitoring of the in vivo chlorophyll a (Chl a) fluorescence and the incorporation of the irradiance as a new environmental variable related to previous studies in the cave, have allowed us to improve our knowledge about the photosynthetic pattern of the biofilms of the cave. Effective quantum yield (ΔF/F_m′) and relative electron transport rate (rETR) were determined during periods of the light, whereas the maximal quantum yield (F_v /F_m) was determined during dark periods. Increases in …

Retroviral Infection Dynamics In Maine's Wild Turkeys, Stephanie A. Shea

Electronic Theses and Dissertations

Widespread wild turkey reintroductions in the late 1900s have led to increases in population density and geographic distribution across North America. This rapid population expansion has put them into proximity with closely-related wild and domestic avian species, increasing the risks of pathogen transmission. Lymphoproliferative disease virus (LPDV) is an avian oncogenic retrovirus detected in wild turkeys in 2009, and previously known to infect domestic turkeys. Following its initial detection, surveys reported variable LPDV prevalence across eastern North America with most wild turkeys being asymptomatic, however diagnostic cases revealed 10% mortality of LPDV-infected individuals. Given its recent detection, little is known …

Soil Microbial Community Dynamics In Response To Prescribed Extreme Fires Following Juniperus Virginiana Invasion In The Loess Canyons Of Nebraska, Julie A. Fowler

School of Natural Resources: Dissertations, Theses, and Student Research

In Nebraska and other regions of the Great Plains, the conifer Juniperus virginiana (eastern redcedar) is converting grasslands to dense woodlands. This is driven by the interacting drivers of fire suppression, altered grazing regimes, climate change and other anthropogenic factors, impacting the provisioning of ecosystem services. This vegetation state transition modifies water resource regulation and biogeochemical cycles leading to altered edaphic properties including soil microbial community composition. To restore these grasslands and control J. virginiana spread, prescribed extreme burns are implemented as a management tool through local prescribed burn associations. We hypothesized that the alternative state transition to dense J. …

Microbial Community Dynamics Of A Microcystis Bloom, Helena Pound

Doctoral Dissertations

Harmful algal bloom events are notoriously associated with massive economic and environmental consequences, causing wildlife and human health risks. As these blooms increase in occurrence, duration, and severity around the world, it is essential to understand conditions leading to bloom formation and why they persist. Abiotic factors such as nutrients are commonly considered in bloom dynamics, but biotic interactions with co-occurring microbial species and viruses must also be taken into account. Harmful algal blooms dominated by the cyanobacterial genus Microcystis occur in bodies of water around the world and provide an ideal system in which to study top-down controls on …

From Microbes To Management: Spatial And Temporal Variations In Available Vegetation Affect The Gut Microbiota In A Population Of Free-Ranging Generalist Herbivores, Olivia K. Rodríguez

Boise State University Theses and Dissertations

The effects of extrinsic environmental factors that shape ecological systems are not only seen at the macroscopic level, but additionally influence and govern the host-associated microbial communities of their mammalian hosts. These microbial communities are susceptible to the fluctuation of abiotic and biotic factors which affect their host organisms. The surge in the research of microbiota–communities of archaea, bacteria, fungi, and viruses residing in various environmental systems–has shown that these communities can profoundly influence animal health. As such, monitoring microbiota has allowed for a new approach to study animal health and physiology. This is of particular benefit in the conservation …

The Effect Of Disturbance And Invasion On Fungal And Plant Communities Over An Elevational Gradient, Adam N. Trautwig

Doctoral Dissertations

High-elevation ecosystems are at risk of disruption from the future effects of climate change. Sub-alpine meadows are a source of unique plant populations, intraspecific variation of elevationally extreme populations, and vital sources of fresh water resources. We evaluated the whole fungal communities, arbuscular mycorrhizal fungal (AMF) communities, plant communities, and edaphic variables of sub-alpine meadows in undisturbed, disturbed, and disturbed with a non-native member of the Brassicaceae (Thlaspi arvense) plots. In conjunction with measuring the effects of disturbance on native communities we conducted potting experiments on a dominant grass of sub-alpine meadows (Festuca thurberi). We also …

A Novel Approach For Characterizing The Ultra-Micro Size-Fraction Community, Abdullah Ahmed Salim, Priscilla Nicole Pineda, Isabella Alamilla, Andrew Dean Putt

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

A Novel Approach for Characterizing the Ultra-Micro Size-Fraction Community

Students: Abdullah Salim, Priscilla Pineda, Isabella Alamilla

Mentors/Supervisors: Andrew Putt, Terry C. Hazen

ABSTRACT

The ultra-micro size-fraction (UMSF) are bacteria that can pass through the 0.2 µm pore membrane filters employed in environmental surveys. Despite being ubiquitous and having high metabolic activity, UMSF remain elusive and largely uncultured. Investigations of UMSF are skewed by difficulties in culturing and a lack of techniques for measuring UMSF biogeochemical signatures. This study measures surface stream UMSF community diversity, and community response to the addition of the synthetic pharmaceutical and cosmetic carbon product cyclodextrin which …

Factors Influencing Primate Hair Microbiome Diversity, Catherine Kitrinos

Masters Theses

Primate hair is both a substrate upon which essential social interactions occur and an important host-pathogen interface. As commensal microbes provide important immune functions for their hosts, understanding the microbial diversity in primate hair could provide insight into primate immunity and disease transmission. While studies of human hair and skin microbiomes show differences in microbial communities across body regions, little is known about the nonhuman primate hair microbiome. In this study, we collected hair samples (n=159) from 8 body regions across 12 nonhuman primate species housed at 3 US institutions to examine 1) the diversity and composition of the primate …

Soil Bacteria: Metabolic Diversity In A Wildlife Management Area, Nicholas Green

Symposium of Student Scholars

This research is part of a larger study linking the soil microbiome and processes to the aboveground plant community.

Soil samples were collected from six plots under closed canopy in the Sheffield Wildlife management area in the Piedmont ecoregion of Georgia in Paulding County. Two of the plots were located in the longleaf pine savanna where restoration of longleaf pine has been in place since 2010. Samples were collected in sterile plastic tubes at the center of each plot and 10 meters above and below the center. For each sample, soil pH and the concentration of nitrogen (N), phosphorus (P), …

Community Level Physiological Profiling Of The Longleaf Pine Savannah Microbiome, Gavin Treadaway

Symposium of Student Scholars

Soil microorganisms secrete chemicals into their surroundings, which the root system will uptake and in return release root exudates, which usually consist of low-molecular-weight organic compounds. These root exudates behave as signaling molecules and substrates for microorganisms to recruit beneficial soil bacteria to the plant root system, which will provide the plants with immunity to foliar diseases and pathogen infection. Studies have shown that bacteria on the root surface can protect aerial sections of the plant by promoting induced systemic resistance, a mechanism of increasing physical or chemical barriers of the plant.

The longleaf pine is an endangered species of …

Microbes On The Mountain: Plant-Microbe Associations And Interactions On Mount St. Helens, Emily Rose Wolfe

Dissertations and Theses

Plant-microbe associations and interactions provide critical context to studies in both community and ecosystem ecology, especially in systems that are relatively new and still undergoing early successional processes. Microbes can colonize the surfaces and interiors of all plant tissues, and these assemblages vary in composition both spatially and temporally, even within the same plant. Endophytes are bacteria or fungi that spend most of their lifecycles living within plant tissues asymptomatically--typically, "endophyte" refers specifically to aboveground tissues such as leaves and stems, and therefore may have direct influences on defenses against herbivory, pathogen or pest tolerance, and even afterlife effects on …

Analysis Of Symptom Expressions And Transmission Rates Caused By The Plant Pathogen Phytophthora Ramorum On Native Chaparral Plants From The Genus Arctostaphylos, Bharati Gaonker

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Phytophthora ramorum is the causal agent of Sudden Oak death (SOD), ramorum dieback and ramorum leaf blight which affect both forest environments and nurseries. This oomycete pathogen has had a huge economic impact on the nursery and lumber industry. Forests in California have experienced substantial mortality of oaks affecting the forest dynamics and diversity. Our research investigates four native species and two ornamental cultivars of plants, which belong to the genus Arctostaphylos (manzanita) and are considered to be new hosts for P. ramorum in the chaparral ecosystem of California. Symptom expression and transmission rates were analyzed on Arctostaphylos glauca, …

Identification And Comparison Of Arbuscular Mycorrhizal Fungi And Soil Microbiomes Between American Chestnuts And Surrounding Hardwoods, Sarah Andrews, Geoffrey Eger, Isabella Vahle

Symposium of Student Scholars

Background/Questions/Methods

The introduction of the Chinese chestnut blight in 1904 decimated native American chestnut (Castanea dentata (Marshall) Borkh.) populations. In this study we aim to: 1) document the location of individual chestnuts in our vicinity; 2) document healthy versus blight infected individuals; 3) characterize putative differences in the soil microbiome between infected and non-infected individuals, as well as between chestnuts and hardwood neighbors. With this information we hope to provide new insights into mechanisms that may enhance blight and fungal resistance in American chestnuts through the understanding of the interactions between the trees and their surrounding soil microbiome.

Soil …

Characterizing The Dormancy And Repair Of A Circumneutral Passive Remediation System Receiving Iron And Sulfate-Rich Amd, Garrett Struble

Electronic Theses and Dissertations

The Wingfield Pines remediation system is a ~20-acre circumneutral, gravity-fed system constructed in 2009 to passively remediate Fe from an ~2000 gallon/minute effluent. In 2017, a fracture to the system’s underground cavern caused the AMD effluent to bypass the system, flowing directly into Chartiers Creek and leaving the system decommissioned between 2017-2019. Soil slurry and water samples were collected in the weeks prior to the system’s reinstalment in September 2019 through January 2020 in order to determine the effect of the repair on remediation efficiency and microbial community composition. This study acted as the first to describe the temporary decommissioning …

Using Bacterial And Fungal Inoculation Strategies To Aid In The Wetland Restoration Of Native Plants In Southern California, Amy Alverson, Karina K. Johnston

Honors Thesis

Planting of native species is a key part of ecological restoration, although the encroachment of invasive species and obstacles to seed germination can limit the success of revegetation efforts. The use of indigenous Plant Growth Promoting Rhizobacteria (PGPR) and Arbuscular Mycorrhizal Fungi (AMF) have been shown to increase the long-term height and diameter of native plants and increase soil fertility in certain studies. Inoculation of seeds with native PGPR have also been shown to increase seed germination. In this study, the effect of different inoculation treatments on different plants native to southern California was studied at two sites in the …

Applications Of Comparative Genomics And Data Science To Agricultural And Clinical Research, Katrina A. Schlum

Doctoral Dissertations

The advent of inexpensive, high-throughput whole genome sequencing (WGS) technologies has led to the generation of thousands of related genomes, even from a single study. Large-scale genome analysis has resulted in hypothesis-generating approaches in the fields of clinical, human and agriculture genomics. Additionally, population-level genomic sampling has resulted in a decrease in false positives in genotype-phenotype associations and an increase in understanding of the basis of disease, antibiotic and pesticide resistance. Deeper understanding of migration, genetic divergence and evolution has also been made possible due to WGS. This research applies comparative genomics, population genomics and data science approaches to whole …

Contaminated Mycoscapes: Designing With Living Organisms, Maria Gutierrez, Elise Zilius

Architecture Senior Theses

The Anthropocene has stripped the planet of its resources, leaving behind an abundance of contamination. The built environment no longer meets the standards set by our turbulent planet. Humankind has lost the privilege of agency in design and construction. Construction methods have failed to evolve concurrently to the intense accumulation of waste; remaining firmly rooted in the materiality of the past, they have upheld architectural notions of stagnancy, cleanliness, and hygiene and ignore the rapidly changing conditions of the environment. This investigation uses contamination to fuel mycelial growth and construct emergent forms whilst executing remediation strategies for polluted sites of …

Mysteries And Uncertainties In Tracing Cryptic Viral Infections, Melaina Jacoby

Undergraduate Honors Theses

Viruses are the most abundant biological entities on Earth. Viral impacts are evident from the level of individual cells and population all the way up to ecosystems and global elemental cycles. Since bacteriophages (viruses that infect bacteria) were first identified in the early twentieth century, the study of these fascinating entities has shown how viral dynamics within ecosystems can influence microbially-mediated processes at a large scale. Viral infections can impact hosts and host-mediated processes in in multiple ways, one of which is through cryptic infections. This state, in which a bacterium may harbor a cryptic phage infection, is known as …

Vignette 14: Eelgrass Wasting Disease, Olivia Graham, Morgan Eisenlord, Drew Harvell

Institute Publications

Rising seawater temperatures can increase the risk of disease outbreaks in many taxa. Pathogens are potentially the ultimate keystone species in that their small biomass can have massive impacts that ripple through ecosystems. Disease outbreaks can be particularly damaging when they affect ecosystem engineers, such as seagrasses. Outbreaks of wasting disease in seagrasses are one of a myriad of stressors associated with declining temperate and tropical seagrass meadows around the globe. Levels of eelgrass wasting disease are high in the San Juan Islands and Puget Sound. These increasing levels of disease are a threat to sustainability of eelgrass meadows, our …

Resistance Of The Freshwater Microbiome To A Combination Of Pesticides, Gabriel Hooper

Senior Honors Theses

Pesticides are used prevalently throughout the United States and can negatively affect non-target organisms. Rain run-off can move multiple pesticides into freshwater ecosystems and bring them in contact with non-target organisms that have variable tolerances to pollution. This study seeks to improve our understanding of how an acute exposure to a combination of pesticides may restructure microbial communities by examining the microbiome before and after a 48-hour exposure to 2000 ppb of herbicides (glyphosate, atrazine, and 2,4-D). Pesticide exposure did not significantly alter the alpha or beta diversity of the sample types, which demonstrates the ability of freshwater microbiomes to …

Microplastics: Nacogdoches County’S Hidden Threat, Jordan Stanford, Sydney Matlock, Courtney Sims, Samantha Montes

Undergraduate Research Conference

Microplastics and their threat to marine environments are well known, but studies in freshwater environments are few and far between. Microplastics can be created by the breaking down of plastics or in the process of making plastics. They affect biological lifeforms in a multitude of ways, water temperature, permeability of the sediment. Pollution in Texas waterways have motivated groups like the Environmental Protection Agency, Trash Free Texas, and Environment Texas to get involved. The objectives of this study are two analyze Bonita and La Nana Bayou for microplastic presence and to educate and create awareness for Nacogdoches County on microplastics. …

Growth Of Diatom Fistulifera Alcalina In Bacterial Co-Culture And Comparative Mitogenomics Of Fistulifera Species, Erwin David Berthold

FIU Electronic Theses and Dissertations

Diatoms are excellent biological models of growth and intracellular oil generation. The productivity and compounds of diatoms, especially oils, support aquatic food chains and human medical and industrial needs. The qualities that made diatoms prolific producers, specifically diatom physiological features such as growth rates with intracellular lipid storage in alkaline environments, are however poorly understood. Another physiological aspect that remains unexplored is the effects of bacteria on the growth and lipid production of alkaliphilic diatoms. More studies, especially co-cultures, are needed for advances in diatom biology and strain performance for the algal biotechnological field. Besides physiology, diatom genetics using next-generation …

Monitoring Lake Sinclair, Margaret Blackledge

Graduate Research Showcase

Algae, a polyphyletic group of aquatic primary producers, play a great part in earth’s biosphere. They produce half of the world’s oxygen and are major contributors to aquatic biodiversity. When conditions are favorable to a species, algae will bloom. Some algal species will produce algal toxins during a bloom as a potential mechanism to concentrate carbon. Due to the integral part they play in aquatic food webs, nutrient cycling and the potential for harmful algal blooms, algal communities are monitored to determine the health and safety of aquatic environments. Lake Sinclair in middle Georgia is a good model where in …

Impact Of Arbuscular Mycorrhizal Fungi On Conyza Canadensis Drought Responses And Possible Mechanisms, Kian G.M. Speck, Ylva Lekberg, Anna Sala

Undergraduate Theses, Professional Papers, and Capstone Artifacts

• Arbuscular mycorrhizal fungi (AMF) are important plant mutualists that can facilitate plant responses to various environmental stressors, such as drought. A plant that may benefit from AMF-induced drought tolerance is Conyza canadensis due to its ability to thrive in dry conditions and its high colonization rate. However, no studies have researched C. canadensis in this context and the exact mechanisms of AMF-induced drought tolerance are still unknown.
• To better understand if and how AMF facilitate drought response in C. canadensis, we conducted a greenhouse experiment comparing the response of mycorrhizal and non-mycorrhizal plants to three watering levels. We measured …

Sarracenia Purpurea As A Model System For Aquatic Ecosystem State Changes And Their Impact On Bacterial Communities, Amanda Claire Northrop

Graduate College Dissertations and Theses

Aquatic ecosystems can undergo abrupt and long-lasting transitions from one state to another, often with negative ecological and economic consequences. With anthropogenic enrichment, aquatic ecosystems such as lakes and ponds may shift rapidly from an oligotrophic, clear water state to a eutrophic, turbid state. These shifts, or state changes, generally occur due to a phenomenon called hysteresis in which the relationship between a driving variable and ecosystem variable depend on the current state of the ecosystem. Such dynamics often make recovery difficult or impossible. Though state changes in aquatic ecosystems have been studied extensively since the 1970s, there have been …

Tree Species Influence On Microbial Functional Gene Abundance And N Cycling In Riparian Soil, Elizabeth Matejczyk

Graduate Theses, Dissertations, and Problem Reports

Little is known about how above-ground vegetation may differentially influence the below-ground microbial community structure, abundance, and function. Abundance of soil microbial N cycling genes responsible for nitrification (amoA), denitrification (nirK and nirS), and nitrous oxide reduction (nosZ) may vary with tree species and increasing N availability, and these variables may be used to predict production of NO₃^- and N₂O from soil. Variability of nitrification and denitrification rates have also been linked to tree mycorrhizal associations, with soil beneath tree species associated with arbuscular mycorrhizal (AM) exhibiting greater denitrification rates …

Initial And Advanced Stages Of Microbiota Establishment Within The Tsetse Fly, Miguel Eduardo Medina Munoz

Graduate Theses, Dissertations, and Problem Reports

Symbiosis is a long-term physical association between two or more species, although little is known regarding its evolutionary origins, particularly at the genetic level. Tsetse flies are the vector of African trypanosomes, causative agents of Human and Animal African Trypanosomiases. Tsetse provide an ideal model for studying initial and advanced stages of symbiosis. Tsetse have a simple digestive tract microbiota primarily consisting of two bacteria; the ancient mutualist Wigglesworthia glossinidia and the recently acquired Sodalis glossinidius. This work presents a chronological study in evolutionary terms of the history of a microbial-insect association. First, I present concepts on symbiosis and …