Life Sciences Commons^™

Macroinvertebrate Community Composition, Food Web Structure, And Emergence Rate In Neotropical Cloud-Forest Streams In Mindo, Ecuador, Anna M. Harris

Masters Theses

Tropical cloud forest streams are one of the most threatened and understudied ecosystems in the world. Understanding how these ecosystems function is essential for effective conservation. In this study, macroinvertebrate community composition, functional feeding group analysis, ecosystem attributes, and physicochemical parameters were used to evaluate biophysical stream conditions of 3 low-order Neotropical cloud forest streams at Reserva Las Gralarias in Mindo, Ecuador. Additionally, food web structure was analyzed via stable isotope analysis and aquatic insect emergence rate was also examined. As stream size increased from 1st to 3rd order, the macroinvertebrate communities shifted from being collector-gatherer dominated (65.2 to 29.8%, …

Physiology And Genetics Shape The Microbiome Of A Seabird Species (Oceanodroma Leucorhoa) More Than Environmental And Social Factors, Douglas Steven Pearce

Masters Theses

The microbiome provides multiple benefits to animal hosts that can profoundly impact health and behavior. Microbiomes are well-characterized in humans and animals in controlled settings, yet assessments of wild bird microbial communities remain vastly understudied. This study examines the multiple factors that affect the microbiome of a burrow-nesting Procellariiform bird species, Leach’s storm-petrel. 16S rRNA-based Illumina Mi-Seq analyses are used to assess the composition and structure of bird and burrow-associated bacterial communities. Results indicate that sex and skin site contribute to bird-associated bacterial community variation, and MHC heterozygosity impacts these bacterial assemblages in a sex and site-specific manner, potentially having …

The Role Of Micrornas In Regulating The Translatability And Stability Of Target Messenger Rnas During The Atrophy And Programmed Cell Death Of The Intersegmental Muscles Of The Tobacco Hawkmoth Manduca Sexta., Elizabeth Chan

Masters Theses

A variety of diseases lead to the atrophy and/or death of skeletal muscle. To better understand the molecular mechanisms that mediate these processes, I have taken advantage of the intersegmental muscles (ISMs) of the tobacco hawkmoth Manduca sexta, which undergo sequential programs of atrophy and programmed cell death at the end of metamorphosis. ISM death is mediated by changes in gene expression and numerous cell-death associated transcripts have been identified. MicroRNAs (miRs) are small (~22 nucleotide) non-coding RNAs that bind to sequences in messenger RNAs (mRNAs) and either cause translational arrest or mRNA degradation. To test the hypothesis that …

Green And Choking: Exploring The Dynamics Of Seasonal Productivity And Hypoxia In A Great Lakes Area Of Concern And Habitat Blueprint Estuary Using Time-Series Measurements, Anthony D. Weinke

Masters Theses

Although hypoxia (dissolved oxygen <4 mg L-1) in the bottom waters of lakes, reservoirs, and estuaries may be a natural product of stratification in eutrophic or mesotrophic systems, there is increasing concern because the occurrence of hypoxia is spreading in many areas where hypoxia did not previously exist. Part of this new knowledge can be attributed to time-series data from buoy observatories that monitor systems in good weather and in bad, and allowing insight into the inner workings of a lake where sampling only a few times per year would not. This study made use of a five-year time-series of meteorological and water quality data in order to examine the effect of episodic wind-events on stratification and hypoxia within Muskegon Lake, Michigan, as well as performing bi-weekly lake-wide monitoring to evaluate the effects of stratification, hypoxia, and wind-events on the lake. In the wind-event portion of the study, we found that events where wind speeds were above average for an extended period of time occurred fairly frequently on the lake, but that thermal stratification allowed only the strongest events to significantly mix the water column at the buoy location a few times per year. This provided infrequent relief of hypoxia in the bottom waters. The second portion of the study found extensive effects on the water quality and biology in the bottom of the lake due to hypoxia such as increased phosphorus concentrations, enhanced phycocyanin following a strong windevent, and decreased fish abundance, richness, and size. We also found that hypoxia occurred lake-wide at all four sample locations, but was most stable at the deepest point in the lake that was least influenced by wind-events. It is possible that the combination of hypoxia and strong episodic wind-events leads to entrainment of phosphorus-rich waters to the surface initiating or continuing an algal bloom. Hypoxia and wind-event mediated internal loading of phosphorus could be a positive feedback loop for cyanobacterial blooms and hypoxia in Muskegon Lake.

Examining The Effect Of Climate Change On The Upper Mesophotic Coral Montastrea Cavernosa (Linnaeus 1767), John Skutnik

Masters Theses

Coral reefs are under increasing pressure from global climate change. In particular, ocean warming is having a deleterious effect on many of the world’s shallow reefs. Some authors suggest that acute exposure is more detrimental than chronic, versus others who indicate the opposite. However, little knowledge exists regarding heat induced stress on deeper mesophotic reefs. Here, I examined the effect of acute (72 hrs.) and chronic (480 hrs.) heat stress using laboratory experiments on coral Montastraea cavernosa (Linnaeus 1767) collected from an upper mesophotic (~30 m) reef off Islamorada Florida. I examined a variety of putative immune and stress genes …

Evaluating Foraging Habits, And Estimating Prey Consumption, And Growth Of Brook Trout In A Coolwater Michigan Stream, Graeme R. Zaparzynski

Masters Theses

Brook trout (Salvelinus fontinalis) are a cold water ectotherm whose native distribution includes most of eastern Canada, the upper Midwestern United States, and the eastern and mid- Atlantic United States as far south as Georgia. The native range of brook trout in the United States has been reduced as a result of interspecific interactions with introduced species, and anthropogenic land use changes that drive water temperature changes in many of their native watersheds. Anthropogenic land-use changes tend to increase thermal regimes of aquatic systems, affecting brook trout physiology and limiting them to colder, headwater reaches. The threat of …

Trophic Transfer Of A Naturally Occurring Algal Toxin From A Freshwater Lake To Little Brown Bats, Devin Jones

Masters Theses

Microcystis aeruginosa is a species of cyanobacteria capable of producing a hepatotoxin called microcystin. As toxic M. aeruginosa overwinters in the sediments of lakes, it is ingested by some mayfly larvae, such as those of Hexagenia spp., and thus

microcystin bioaccumulates in these insects. When Hexagenia emerge from lakes to

reproduce, they provide an abundant, albeit temporary, food source for many terrestrial

organisms such as bats. Little brown bats, Myotis lucifugus, likely feed opportunistically

on aquatic insects. To test if microcystin moves from aquatic to terrestrial ecosystems via trophic transfer, we 1) tested bat feces for the presence of …

From Land To Lake: Contrasting Microbial Processes Across A Great Lakes Gradient Of Organic Carbon And Inorganic Nutrient Inventories, Deborah K. Dila

Masters Theses

Freshwater ecosystems have strong linkages to the terrestrial landscapes that surround them, and contributions of carbon and inorganic nutrients from soil, vegetation and anthropogenic sources subsidize autochthonous water body productivity to varying degrees. Abundant freshwater phytoplankton and bacterioplankton are key to linking the planet's geosphere and atmosphere to the food webs in the hydrosphere through their growth and respiration. Rich resources that move through land margin waterways make them active sites for cycling organic carbon and thus important, but understudied, contributors to global climate. During 2010-2011, we examined seasonal changes in carbon and nutrient inventories, plankton community composition and metabolism …

Evaluation Of Total Mercury And Methylmercury Concentrations Of Terrestrial Invertebrates Along Lower East Fork Poplar Creek In Oak Ridge, Tennessee, Chelsea Lynden Standish

Masters Theses

Mercury (Hg) and methylmercury (MeHg) are environmental concerns due to their abilities to cause neurological, reproductive, and other physical damage to wildlife. Lower East Fork Poplar Creek (LEFPC), stemming from the Y-12 National Security Complex, located in Oak Ridge, TN, has elevated concentrations of inorganic mercury, a majority of which was released between 1950 and 1963. This inorganic mercury has been, and is currently, converted to methylmercury. An ecological assessment in 2011 revealed high concentrations of methylmercury in riparian spiders along LEFPC. These results suggested the transfer of mercury from aquatic to terrestrial systems may be higher than previously expected …

Curcumin And Its Oxidative Degradation Products: Their Comparative Effects On Inflammation, Julia Zhu

Masters Theses

The anti-inflammatory agent curcumin degrades rapidly, leading to speculations that curcumin’s reported effects stem from its degradation products. Curcumin can degrade via hydrolysis, and more recently it was discovered that curcumin can degrade via oxidation at physiological pH. Additionally, bicyclopentadione is the major degradation product from this oxidation reaction. Evidence from the literature suggests that curcumin degrades primarily through oxidation. However, the biology of the oxidation products is not well characterized, and there is debate on whether oxidation intermediates or curcumin itself is more biologically active. To further elucidate the biology of the oxidation products, their effects on inflammation were …

Evaluating A Novel Photochemical Tool For Labeling And Tracking Live, Endogenous Calcium-Permeable Ampars, Rosamund Elizabeth Combs-Bachmann

Masters Theses

The purpose of this research is to advance development of a photochemical tool designed to probe the role of ionotropic glutamate receptor signaling in neurodegenerative processes, and to delve more deeply into the biological processes underlying the role of these receptors in signaling and memory formation. This ligand-targeted nanoprobe was designed and developed in our lab to label endogenous calcium-permeable AMPARs (CP-AMPARs) in live cells with minimal disruption to native receptor activity. Nanoprobe is designed to use naphthyl acetyl spermine (NASPM) as a photocleavable ligand to target and covalently label native CP-AMPARs with a non-perturbing, fluorescent marker that then allows …

Heterochrony Of Cranial Bones In Amniota And The Phylogenetic Placement Of Testudines, Kathleen Sagarin

Masters Theses

The study of developmental systems may help to resolve the disagreement between morphological data and molecular data when it comes to the placement of Testudines among Amniota. Among other unique morphological adaptations, turtles possess an anapsid (unfenestrated) condition of the temporal region of the skull. If turtles are descended from diapsids, as molecular data suggests, this implies a rapid transformation of the temporal region from the diapsid condition to the anapsid condition. This study specifically addressed temporal bone heterochony among amniotes using the methods of Continuous Analysis (Germain and Laurin 2009) and Parsimov-based Genetic Inference (Harrison and Larsson 2008) to …

Sequestered Alkaloid Defenses In The Dendrobatid Poison Frog Oophaga Pumilio Provide Variable Protection From Microbial Pathogens, Kyle Hovey

Masters Theses

Amphibians produce the majority of their defensive chemicals, however alkaloid defenses in poison frogs are sequestered from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. However, alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in poison frog alkaloid defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect frogs. …

Variation In Alkaloid Defenses Of The Dendrobatid Poison Frog Oophaga Pumilio Lead To Differences In Avaoidance By Arhtropods, Sarah Bolton

Masters Theses

Conspicuously colored dendrobatid frogs sequester alkaloid-based defenses from dietary arthropods, resulting in considerable alkaloid variation among populations. Although alkaloids act as a defense against predation, relatively little is known about how alkaloid variation is perceived and functions as a defense against predators. Throughout its geographic range, previous studies have found the dendrobatid frog Oophaga pumilio to have particularly variable alkaloids, and that differences in these alkaloids are associated with differences in toxicity to laboratory mice. Although toxicity is one measure of alkaloid variation, predator avoidance of dendrobatids might simply be due to the bitter or unpalatable nature of alkaloid defenses. …

Population Genetics And Genomics Within The Genus Pityopsis, Elizabeth Anne Hatmaker

Masters Theses

Pityopsis (Asteraceae) includes seven species; one species, P. ruthii, is federally endangered. The genus exhibits a range of ploidy levels, widespread hybridization among species with overlapping ranges, and interesting adaptive traits such as fire-stimulated flowering. However, taxonomy of Pityopsis has remained unresolved. Resolving interspecific relationships can lead to a deeper understanding of the inheritance and hybridization patterns, as well as the evolution of adaptable traits. Our first objective was to examine population structure and gene flow within Pityopsis ruthii. Polymorphic microsatellite markers (7 chloroplast and 12 nuclear) were developed and used to examine genetic diversity of 814 P. …

Diet Of And Prey Availability For Reintroduced Juvenile Lake Sturgeon (Acipenser Fulvescens) In Ft. Loudoun Reservoir, Tennessee, Todd Michael Amacker

Masters Theses

After fifteen years of reintroducing juvenile Lake Sturgeon (Acipenser fulvescens) in the Upper Tennessee River Basin, fisheries biologists are researching basic ecological traits of subsistent organisms. I set out to seasonally assess whether Lake Sturgeon forage opportunistically or selectively in Ft. Loudoun Reservoir. After anesthetizing individual juvenile Lake Sturgeon caught on trotlines in a 13-km reach of the reservoir, I used colonic flush and gastric lavage techniques to describe diets quantitatively. I also used two methods to assess available prey items in the study area by 1) taking systematic benthic grabs along several transects across the width of …

Estimating Avian Populations With Passive Acoustic Technology And Song Behavior, Stephanie C. Prevost

Masters Theses

The need for improvements in avian wildlife monitoring efficiency, accuracy, and scope has led to use of new technologies such as autonomous recording units (ARUs). As a monitoring tool, passive acoustic recording has numerous benefits, but it is still limited to use in human-accessible areas. There is also need for monitoring technologies in areas that are inaccessible. Military installations, which host a disproportionately large number of threatened, endangered, and at-risk species compared to other federal lands, pose the accessibility problem with sizeable impact areas that are too hazardous for humans to access. This thesis introduces the Balloon Aerial Recording System …

Detection And Attribution Of Long-Term Vegetation Changes In Northern Alaska, Robert Barrett

Masters Theses

Climate change is impacting terrestrial ecosystems world-wide and the Arctic is particularly vulnerable as it is warming faster and with greater magnitude than other regions. Understanding the responses of arctic plants species to abiotic factors is crucial to predicting the impact climate change will have on the Arctic because plants play critical roles in carbon exchange, energy balance, and trophic interactions. Using data from long-term research sites in Barrow and Atqasuk, Alaska, the purpose of this thesis was to investigate how arctic plants respond to 17-19 years of experimental warming, establish the relative strengths of various abiotic factors in predicting …

The Effect Of Seasonal Fish Migration On Energy Budgets In Two Coastal Michigan Streams, Emily M. Dean

Masters Theses

Migratory fish are known to seasonally enter coastal stream systems but the magnitude of the effects these migrations have on stream energy budgets is not fully understood. The Laurentian Great Lakes have several introduced and native adfluvial fish, where only a few studies have investigated the impacts of their migration on energy budgets in Michigan coastal streams. We quantified the contribution of energy from Chinook salmon (Oncorhynchus tshawytscha) muscle and eggs, steelhead (Oncorhynchus mykiss) eggs, and larval white suckers (Catostomus commersonii) to coastal stream energy budgets. Energy densities and energy delivered to streams were estimated using bomb calorimetry and annual …

Does Phosphorus From Agricultural Tile Drains Fuel Algal Blooms?, Delilah R. Clement

Masters Theses

Phosphorus (P) is often implicated as a contributing factor to algal blooms. Attention has been focused on P in surface runoff, but agricultural tile drains also can be a source. Lake Macatawa is a hypereutrophic lake located in west Michigan, and the watershed is dominated by row crop agriculture. Further research is needed to understand the influence of bioavailable P originating from tile drains on water quality in Lake Macatawa. The objectives of this study were to 1) conduct a tile drain effluent sampling survey to assess their importance as a source of P in the Macatawa Watershed; 2) investigate …

Spatiotemporal Analysis Of Gene Flow Patterns Among Woodland Salamander Populations Inhabitating Contrasting Landscapes, Alexander C. Cameron

Masters Theses

Dispersal is a fundamental evolutionary process that serves as a mechanism by which local populations remain connected through space. Habitat loss and fragmentation remain widespread threats to biodiversity globally, and therefore it is imperative to understand how dispersal patterns are affected by anthropogenic modifications of the environment. Using a panel of 10 novel microsatellite loci, I estimated gene flow patterns over historical and contemporary timescales among populations of Eastern Red-backed Salamanders (Plethodon cinereus) in a previously unstudied portion of the species range. Four focal populations reside within a highly fragmented urban center whereas the remaining four focal populations persist in …

Revision Of The Synechococcales (Cyanobacteria) Through Recognition Of Four Families Including Oculatellaceae Fam. Nov. And Trichocoleaceae Fam Nov. And Seven New Genera Containing 14 Species, Truc Mai

Masters Theses

A total of 48 strains of thin, filamentous cyanobacteria in the Synechococcales were studed by sequencing 16S rRNA, rpoC1, and rbcLX gene fragments. A subset of these were carefully characterized morphologically. Bayesian analysis of the 16S rRNA gene data in a large alignment of Synechococcales (345 OTU's) was in agreement with the phylogeny based on the rpoC1 gene for 59 OTU's. Both indicated that the large family-level grouping formerly classified as the Leptolyngbyaceae could be further divided into four family-level clades. Two of these family-level clades have been recognized previously as Leptolyngbyaceae and Prochlorotrichaceae. The Oculatellaceae fam. prov. and Trichocoleaceae …

Phytoforensics Tools: The Degradation And Detection Of Chlorinated Solvents In Integrated Systems, Tommy J. Goodwin Jr.

Masters Theses

"Due to decades of mismanaged pollutants entering groundwater, subsurface pollution of various compounds has become a widespread challenge. Chlorinated solvents are the most common groundwater contaminants that persist in aquifers, and remediation of these wide-spread plumes is difficult. Bioremediation, permeable reactive barriers, and phytoremediation are remedial technologies that have been developed and applied to chlorinated solvents in groundwater systems. This study integrates these technologies in different combinations to demonstrate the remediation potential of this approach. Zerovalent iron (ZVI) and bioaugmentation with a Dehalococcoides sp. (DHC) culture were applied separately and in combination for degradation of perchloroethene (PCE). Salix pentandra were …

Cyanomargarita Gen. Nov. (Nostocales, Cyanobacteria): Convergent Evolution Resulting In A Cryptic Genus, Sergey Shalygin

Masters Theses

Two populations of Rivularia-like cyanobacteria were isolated from ecologically diverse and biogeographically distant sites. One population was from an unpolluted stream in the Kola Peninsula of Russia, whereas the other was from a wet wall in the Grand Staircase-Escalante National Monument, a desert park-land in Utah. Though both were virtually indistinguishable from Rivularia in field and cultured material, they were both phylogenetically distant from Rivularia and the Rivulariaceae based on both 16S rRNA and rbcLX phylogenies. The new putative cryptic genus Cyanomargarita, with proposed type species C. melechinii sp. nov., and additional putative species C. calcarea are described herein. A …

Correlation Between Sleep And Lifespan In Drosophila Melanogaster, Courtney H. Fiebelman

Masters Theses

”Sleep has previously been associated with lifespan. Monitoring sleep in any given fly over their lifetime facilitates the ability to predict the lifespan of that given fly. Using this estimate, lifespan can potentially correlate with biological age to identify when health parameters have declined.

To confirm that the prediction algorithm could identify short and long-lived flies, glutathione levels in heads and bodies were compared between two groups. The results showed this to be consistent in the bodies of wild-type Canton S male flies, and showed that glutathione was decreased in the predicted biologically older flies. These data show that glutathione …