Life Sciences Commons^™

Effects Of Large Wood Additions On Basal Resources, Macroinvertebrates, And Ecosystem Processes In The Narraguagus River, Maine, Val Watson

Electronic Theses and Dissertations

Ecological restoration is an increasingly common practice across ecosystems, and current practices aim to restore the biological and physical processes underlying ecosystem function, often for the sake of endangered higher-level consumers. Studies of restoration outcomes often report few or inconsistent ecological changes, and monitoring of restoration projects rarely measures ecological processes. Monitoring also usually measures outcomes at a single scale, despite the prevalence of scale- dependent phenomena across ecosystems. My thesis uses measurements of ecological processes to assess restoration response and evaluates responses across multiple scales. I focus here on a long-term large wood addition project on the Narraguagus River …

Muscle Defects Lead To Skeletal Deformities In A Zebrafish Model Of Distal Arthrogryposis, Emily A. Tomak

Electronic Theses and Dissertations

Distal Arthrogryposis Type 1 (DA1) involves mild muscle weakness and limb skeletal abnormalities thought to be caused by paralysis in utero. Why the limbs are particularly affected in DA1 and the degree of paralysis that leads to these skeletal deformities in utero remains unclear. Several muscle genes are known to cause DA1, including MYLPF (myosin light chain phosphorylatable), which encodes a myosin light chain protein that binds close to the force-generating head of myosin heavy chains. The zebrafish mylpfa^-/- mutant displays a phenotype consistent with DA1, including impaired myosin activity, reduced muscle force overall, and complete fin paralysis. I …

The Relationship Between Intuitive Eating And Body Mass Index And Diet Quality In College Students, Ashley A. Reynolds

Electronic Theses and Dissertations

Objective

The objective of this research was to explore the influence of intuitive eating (IE) on body mass index (BMI) and diet quality (DQ) among college students.

Methods

A cross-sectional convenience sample of college students completed an online survey consisting of the short-Healthy Eating Index (SHEI) and the Intuitive Eating Scale-2 (23 items). Body mass index was calculated using self-reported height and weight. Descriptive statistics were used to assess group characteristics. A linear regression was used to test if IE scores significantly predicted BMI. An independent t-test was used to compare BMIs of students with IE scores above and below …

Conceptualization And Perceptions Of Student Preparedness In Quantitative Reasoning Among Introductory Biology Faculty, Ann Cleveland

Electronic Theses and Dissertations

Quantitative reasoning (QR) is a crucial competency as undergraduate biology students complete their academic program and enter a workforce increasingly reliant on analyses of vast and complex data sets. The need to prepare biology majors for the 21^st century workforce was cited in Vision and Change: a Call to Action (American Association for the Advancement of Science [AAAS], 2011). The Vision and Change document also advocated for curriculum reform to incorporate QR instruction in undergraduate biology programs. Biology education researchers answered this call with a wealth of research examining undergraduate QR competencies, barriers and challenges to QR learning in …

Comparative Energetics Of Mammalian Thermoregulatory Physiology, Ana M. Breit

Electronic Theses and Dissertations

Endothermy allows species to decouple body temperature from environmental
temperatures but does not equate to endothermic species maintaining those constant temperatures. Instead, heterothermy fluctuating body temperatures, both in and outside of torpor is common and allows endotherms to expand the limits of thermoneutrality. Thermolability is likely to be more common in the tropics and subtropics, where species live within or above their thermoneutral zone. My dissertation research focused on the heterothermic-homeothermic continuum, specifically quantifying where on the continuum different species fall at certain times and why those species have evolved to be at those points. I quantified the thermal profile …

Genetic Characterization Of Centromere-Mediated Uniparental Genome Elimination In Arabidopsis, Diana Spencer

Electronic Theses and Dissertations

The production of haploids through crossing was first discovered from instances of interspecies crosses in Nicotiana spp. in 1924. Since then, haploid induction crosses has been used to improve plant breeding programs and commercially utilized in a number of crop industries. The generation of doubled haploid instantaneously creates a pure homozygous line, therefore eliminating the need for several generations of inbreeding. There are several pathways to induce haploids in plants: of these methods, centromere-mediated genome elimination pathway engenders the highest haploid induction rate (HIR) with up to 45% in Arabidopsis compared to 15% through phospholipase-mediated haploid induction in maize. Centromere-mediated …

Quantifying Spatial Heterogeneity Of Wild Blueberries And Crop Water Stress Monitoring Using Remote Sensing Technologies, Kallol Barai

Electronic Theses and Dissertations

The wild blueberry is one of the major crops of Maine, with significant economic value and potential health benefits. Due to global climate change, drought impacts have been increasing significantly in recent years in the northeast region of the USA, causing significant economic losses in the agricultural sectors. It has been predicted to increase further in the future. Changing patterns of the elevated atmospheric temperatures, increased rainfall variabilities, and more frequent drought events have made the wild blueberry industry of Maine vulnerable, suggesting the adoption of novel approaches to mitigate the negative impacts of global climate changes. Also, wild blueberry …

Age, Growth, Foraging, And Trophic Ecology Of Bigeye (Thunnus Obesus) And Yellowfin (Thunnus Albacares) Tuna In Continental Shelf And Slope Regions Of The Northeast U.S., Riley S. Austin

Electronic Theses and Dissertations

Traditional stock assessments require, in part, accurate knowledge of growth relationships to estimate a variety of aspects involved in population conservation management of exploited species. In addition, the local distribution and condition of top pelagic predators is driven by detection of abundant forage aggregations and along with traditional stock assessments, should be considered for effective management of marine populations. Empirical analyses of these data are severely lacking for bigeye (Thunnus obesus) and yellowfin (Thunnus albacares) tuna in the Atlantic Ocean, especially for the former. Given historical studies’ observations of these two top predators use as biological samplers due to their …

The Role Of Foxd1 In Clear Cell Renal Cell Carcinoma, Kyle H. Bond

Electronic Theses and Dissertations

Renal cell carcinoma (RCC) is the 8^th most common cancer in the United States, with the clear cell variant (ccRCC) being the most prevalent. Over 14,000 people die every year to RCC, with rates continuing to increase with an aging general population. Patients suffering from metastatic RCC (mRCC) have extremely poor prognoses, with a 5-year survival of only 11.2%. Current treatment options include resection of primary lesions, tyrosine kinase inhibition (Sunitinib, Pazopanib), mTOR inhibition (Temsirolimus, Everolimus), and immune checkpoint inhibition (Nivolumab, Atezolizumab). Recent attention has been drawn to inhibition of transcription factors like HIF2α (Belzutifan). There is a need …

Illuminating Corneal Nerve Injury: Analysis Of Neuronal Phenotypes Following Acute And Chronic Corneal Nerve Injury, Cara Sullivan

Electronic Theses and Dissertations

The cornea is uniquely avascular, transparent, and densely innervated with a highly complex and rapidly adapting sensory system. Combined with the tear film coating its surface, it is the first line of protection for the visual system. Clear vision provides tremendous survival advantage and thus uses long evolved and highly conserved mechanisms within the corneal protective barrier to preserve its function. Corneal nerves have a critical role in maintaining corneal homeostasis, initiating blinking, and tearing circuits to block potentially damaging environmental insults, and for engaging rapid-response regeneration programs. Many of these critical molecular mechanisms have been broadly characterized over the …

Lexicographic Sensitivity Functions For Nonsmooth Models In Mathematical Biology, Matthew D. Ackley

Electronic Theses and Dissertations

Systems of ordinary differential equations (ODEs) may be used to model a wide variety of real-world phenomena in biology and engineering. Classical sensitivity theory is well-established and concerns itself with quantifying the responsiveness of such models to changes in parameter values. By performing a sensitivity analysis, a variety of insights can be gained into a model (and hence, the real-world system that it represents); in particular, the information gained can uncover a system's most important aspects, for use in design, control or optimization of the system. However, while the results of such analysis are desirable, the approach that classical theory …

Marine Aquaculture In Maine: Understanding Diverse Perspectives And Interactions At Multiple Scales, Melissa L. Britsch

Electronic Theses and Dissertations

Coastal oceans are changing and experiencing increased use. The social and ecological benefits of healthy coastal oceans are well documented and include habitats for marine species, storm protection, and recreational opportunities (MEA, 2005). As the impacts of human activities are recognized, questions about how ocean spaces should be used are becoming more common. These questions are complex and involve many tradeoffs. Understanding the values people hold about uses, and how activities and ecosystems overlap, is critical for weighing tradeoffs and improving future management. I use the northeastern U.S. state of Maine to study human interactions with coastal oceans. Maine is …

Biophysical And Stable Isotopic Profiles Of The Salmon Louse Lepeophtheirus Salmonis (Krøyer, 1837), Emma Taccardi

Electronic Theses and Dissertations

The salmon louse Lepeophtheirus salmonis is a parasitic copepod that infects wild and farmed salmonids throughout the northern hemisphere. L. salmonis represents the largest economic hurdle of the Atlantic salmon (Salmo salar) industry, with an estimated annual cost of nearly $1 billion globally due to production losses and anti-parasitic control measures. Salmon farming in Maine has existed for decades and is a critical economic driver, yet the region is underrepresented in global sea lice research. The aim of this work was to examine parasites in the context of animal trophic transfer and characterize physiological condition by quantifying the …

Distributions And Abundances Of The Red Tide Dinoflagellate Alexandrium Catenella In The Eastern Gulf Of Maine And Bay Of Fundy In Relation To Diatoms In June, July And August Of 2019, Kimberly Lina D'Adamo

Electronic Theses and Dissertations

A series of three oceanographic survey cruises were conducted in June, July, and August of 2019 in the northeastern Gulf of Maine and Bay of Fundy. Surface water samples were collected and analyzed for enumerations of cell densities of the dinoflagellate Alexandrium catenella in relation to cell densities of diatoms. Hydrographic profiles of temperature, salinity, and nutrients (silicate and nitrate) were also made at each station. Data were analyzed to determine if there was any statistically significant evidence of allelopathic interference imparted by diatoms that impede A. catenella. A. catenella cells were most abundant in June, reaching 6,195 cells per …

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos

Electronic Theses and Dissertations

Commercial production of lowbush blueberry (Vaccinium angustifolium Aiton) in Maine relies primarily on managed honeybee hives; however, naturally occurring wild bees are more efficient pollinators of the crop. Wild bees have short foraging distances and must nest near crop fields to provide pollination services. After crop bloom, the surrounding landscape must provide sufficient forage to maintain wild bee populations for the remainder of the growing season. Lowbush blueberries in Maine are produced in a mixed-use landscape with two distinct landscape contexts. Here, we document bee communities and habitat resources (nesting and floral) in power line rights-of-way and eight land …

Lead Poisoning In Maine's Common Loons: Examining Biological And Social Dimensions, Brooke S. Macdonald

Electronic Theses and Dissertations

Lead poisoning from ingested fishing tackle is a well-documented conservation concern for adult common loons in the Northeastern United States. To mitigate this issue, the state of Maine began implementing restrictions on lead tackle use in 2002, with new legislation added in 2016 and 2017. In addition to legislative action there have been various non-regulatory strategies employed in Maine to help raise awareness, such as the Fish Lead Free campaign. Human behavior is the root cause of lead fishing tackle in aquatic environments, and also can determine the success of legislative and educational efforts. Measuring underlying factors that influence behaviors, …

The Effect Of Wild Blueberry Bioactives On Endothelial Cell Migration And Angiogenesis: An In Vitro Mechanistic, Genomic And Proteomic Approach, Panagiotis Tsakiroglou

Electronic Theses and Dissertations

The goal of this study is to investigate the effects of wild blueberry fractions (Anthocyanins and Phenolic acids) on vascular function and physiology. More specifically the potential effects of the above fractions and their combination in physiological concentrations on endothelial cell migration, angiogenesis, gene expression and proteins synthesis of markers related to the above processes. The objectives are to study whether anthocyanins, phenolic acids and their combinations (ACNs:PAs) affect: a) cell proliferation, b) speed of endothelial cell migration, c) angiogenesis, d) gene expression of genes critical for cell migration and angiogenesis such as RAC1, RHOA, AKT1, eNOS and VEGF and …

Flower Visitation In Relation To Pollen And Nectar Nutrition: Implications For Pollinator Habitat And Conservation, Megan E. Leach

Electronic Theses and Dissertations

Pollination of both wild and crop plants is at a crossroads; honey bee populations are experiencing losses at a higher rate than ever before, and some native bee species are declining in abundance to the point of being listed as endangered species. A few examples of these threats include pesticide exposure, habitat loss, and climate change. In response to bee population declines, conservation efforts have been initiated to increase habitat quality for bees by planting pollinator reservoirs or gardens. Plants provide nutrition to bees in the form of pollen and nectar. Several studies have shown links between higher nutritional quality …

Detrital Protein Contributes To Oyster Nutrition And Growth In The Damariscotta Estuary, Maine, Usa, Cheyenne M. Adams

Electronic Theses and Dissertations

Oyster aquaculture is an expanding industry that relies on identifying and utilizing natural estuarine conditions for the economically viable production of a filter-feeding crop. The eastern oyster, Crassostrea virginica, is the principal species currently cultured in Maine. In addition to preferentially consumed phytoplankton, various detrital complexes (non-algal and/or non-living organic matter) may provide some nutrition to C. virginica between times of phytoplankton abundance. Here I investigated the importance of detrital proteins in supporting the growth of oysters cultured in the upper Damariscotta Estuary. Oyster aquaculture in this area is highly successful and previous reports indicate that labile detrital protein …

Wildlife Use Of Vernal Pools In An Urbanizing Landscape With A Focus On Population Vitality Of Vernal Pool-Breeding Amphibians, Carly Eakin

Electronic Theses and Dissertations

Vernal pools in the northeastern United States provide essential habitat for pool-breeding amphibians and provide resources for other forest-dwelling wildlife. These pools and pool-breeding amphibians in particular are threatened by land conversion associated with urbanization and urban-associated factors. The responses of these amphibians and of birds and mammals using vernal pools to intermediate levels of urban development are largely unknown. I used field observations and lab experiments to study the amphibians, birds, and mammals associated with vernal pools along an urban development gradient in greater Bangor, Maine.

In Chapter 1, I examined bird and mammal use and assemblage composition at …

Divergent Responses Of Larval And Juvenile Blue Mussels To Low Salinity Exposure, Melissa A. May

Electronic Theses and Dissertations

In this study, we compared the osmotic stress response of larval and juvenile blue mussels (Mytilus edulis) at the transcriptomic, metabolomic, and whole organism levels. Blue mussels inhabit coastal areas, where they face climate-induced reductions in nearshore salinity. Despite their ecological and economic importance, scientists do not fully understand the underlying transcriptomic and cellular mechanisms of the osmotic stress response in blue mussels or how the ability to respond to stress changes throughout development. Blue mussels spend the first weeks of life developing through several larval stages in the plankton. These early life history stages are more vulnerable …

Measuring Fertilization In Populations Of Sea Scallop (Placopecten Magellanicus): Developing And Testing Methods In The Laboratory And Field, Skylar Bayer

Electronic Theses and Dissertations

Most marine organisms are broadcast spawners, releasing their sperm and eggs into the water column. Methods of measuring in situ fertilization have proven successful with a few model species, which are reviewed in my introductory chapter. However, many commercially exploited species, such as the sea scallop Placopecten magellanicus, have been neglected. Sea scallop populations have greatly increased from fishing closures, but the mechanism behind this response is uncertain, particularly in regard to fertilization. In this dissertation I developed a methodology of measuring fertilization success and spawning events of P. magellanicus, tested it in laboratory and field settings, and …

Age Structure Response Of Principal Groundfish To Marine Protected Areas In New England, Julian Chawarski

Electronic Theses and Dissertations

Atlantic cod (Gadus morhua), yellowtail flounder (Limanda ferruginea), and haddock (Melanogrammus aeglefinnus) were once dominant species in the New England fisheries economy, together accounting for over half of the landings value of groundfish. Over the last several decades, all three species have experienced dramatic shifts in spawning stock biomass (SSB) with current estimates for cod stocks at 3% and 7% of target biomass (Gulf of Maine and Georges Bank stocks, respectively), a strong contrast to haddock stocks that are nearly fully recovered (NEFSC 2014, 2017). As principally demersal species, they are easily targeted by …

Development Of An Active-Learning Lesson That Targets Student Understanding Of Population Growth In Ecology, Elizabeth Trenckmann

Electronic Theses and Dissertations

Integrating quantitative literacy skills into the undergraduate biology curriculum has been advocated as a way to better reflect the tools and practices used by scientists. One area where students often need and can develop quantitative skills is population ecology, and previous studies have shown that students often have conceptual difficulties in this area. The focus of this thesis project was to explore student thinking about population ecology and develop an in-class active-learning lesson that incorporates quantitative skills for use in large-enrollment undergraduate biology courses. The development of this lesson was guided by in depth reviews of literature, textbooks, and online …

Roles Of Siphon Flows In Suspension Feeding, Kevin Du Clos

Electronic Theses and Dissertations

Benthic marine suspension feeders provide an important link between benthic and pelagic ecosystems. The strength of this link is determined by suspension-feeding rates. Many studies have measured suspension-feeding rates using indirect clearance-rate methods, which are based on the depletion of suspended particles. Direct methods that measure the flow of water itself are less common, but they can be more broadly applied because clearance-rate measurements are affected by properties of the cleared particles. We present pumping rates for three species of suspension feeders, the clams Mya arenaria and Mercenaria mercenaria and the tunicate Ciona intestinalis, calculated using a direct method …

Shortnose Sturgeon (Acipenser Brevirostrum) Spawning Potential In The Penobscot River, Maine: Considering Dam Removals And Emerging Threats, Catherine Johnston

Electronic Theses and Dissertations

Dam removals from the Penobscot River in Maine restored access to freshwater habitat critical for the life cycle of endangered shortnose sturgeon. Prior to the dam removals, shortnose sturgeon spawning activity had not been documented. Instead, evidence suggested that individuals emigrated from the Penobscot River to spawn in the Kennebec complex, 140 km away. A central question of this thesis was whether spawning activity would commence in the first two years following dam removal. Consistent with pre-dam removal movement patterns determined using acoustic telemetry, the majority (78%) of tagged individuals emigrated from the Penobscot River at some point over the …

Sources Of Ecologically Important Trait Variation In Mosquitofish (Gambusia Affinis And Gambusia Holbrooki), Heather Ann Arnett

Electronic Theses and Dissertations

The study of contemporary evolution and eco-evolutionary dynamics is classically defined in terms of genetic evolution, but the actual suite of processes driving contemporary trait change is likely much more complex than often credited. This dissertation considers additional mechanisms of trait change that might be important to an emerging model system for study of contemporary evolution and eco-evolutionary dynamics. Specifically, the research focuses on phenotypically plastic and demographic trait variation in Eastern and Western Mosquitofish (Gambusia affinis and G. holbrooki) facing the major ecological gradient of predation risk. Plasticity experiments employed a common-garden rearing design to manipulate fish …

Effects Of Melatonin On Heartbeat And Possible Identification Of A Melatonin Receptor In Drosophila Melanogaster, Tricia L. Vankirk

Electronic Theses and Dissertations

Chapter 1 of this manuscript is a literature review that serves as an introduction to the entire dissertation. Chapter 2 examines the effects of the melatonin injection on heart rate and rhythmicity in Drosophila melanogaster Canton-S (wild-type) pupae and pupae bearing a variety of heart mutations. Chapter 3 investigates further the possible mechanisms of melatonin’s ability to increase heart rhythmicity without significantly affecting heart rate. A melatonin antagonist, luzindole; a high-affinity melatonin agonist, 2-iodomelatonin and RNAi techniques are used to identify a possible melatonin receptor in Drosophila melanogaster.

An appendix contains a previously published manuscript detailing experiments performed at the …

Explaining Migratory Behaviors Using Optimal Migration Theory, Jennifer D. Mccabe

Electronic Theses and Dissertations

Bird migration is the regular seasonal movements between breeding and nonbreeding grounds. In general, birds that breed in the Northern Hemisphere tend to migrate northward in the spring to take advantage of increasing insect populations and lower predation pressures and fly south when food availability and weather conditions decline. Embarking on a journey that can stretch a thousand miles round trip is a dangerous and arduous undertaking. While en route migrants must stop and feed to replenish their depleted energy reserves, often in unfamiliar locations with unknown predation pressures. They also must react to weather conditions during flight and while …