Biology Commons^™

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 …

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 …

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. …

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. …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Expression Of Insulin Responsive Genes In Insulin Resistant Conditions, And The Effect Of Selenium On Gene Expression, David L. Ruff

Masters Theses

Chronically high blood glucose levels lead to many problems, such as insulin resistance, the hallmark of Type II diabetes. Increased flux through the hexosamine biosynthesis pathway is one mechanism by which high glucose as well as glucosamine has been shown to induce insulin resistance. This study tests the effects of glucosamine induced insulin resistance on insulin regulation of the metabolic genes glucose-6-phosphate dehydrogenase (G6PDH) and fatty acid synthase (FAS) as well as insulin responsive proteins tribbles homolog (TRIB3) and sterol regulatory element binding protein (SERBP-1c) 1c.

Selenium, a micronutrient has been shown to be an effective insulin mimetic in Type …

Evaluating Accuracy And Bias In Genetic Monitoring Under Scenarios Of Population Decline, Susan K. Munster

Masters Theses

Accurate and unbiased estimates of current effective population size are of primary importance in making informed decisions for conservation purposes. One species of concern, the eastern red bat (Lasiurus borealis), is experiencing ongoing population losses due to wind turbine collisions. The proportion of the population being affected is currently unknown, although recent estimates of total fatalities at wind turbines over the time from 2000-2011 are in the hundreds of thousands for this species alone. The roosting habits of eastern red bats make it difficult to monitor their census population size (Nc); thus, genetic estimates of effective population size (Ne) may …

Microcystin Accumulation In Fish Muscle Tissue: Exploring The Safety Of Fish Consumption In Several Michigan Water Bodies, Heather Snyder

Masters Theses

A variety of anthropogenic factors, including global climate change and eutrophication, are causing increases in cyanobacterial abundance. Increased prevalence of cyanobacteria can be detrimental, as some genera of cyanobacteria have the ability to produce toxic secondary metabolites known as cyanotoxins. The cyanotoxin microcystin- a hepatotoxin, is the most ubiquitous and toxic cyanotoxin in freshwater ecosystems, and has been quantified in a number of aquatic organisms. Microcystin was quantified in 8 fish species from St. Mary’s River in June, Saginaw Bay in September, and from Stony Creek Lake in October in 2014 by the Michigan Department of Environmental Quality and the …

Toxin Production And Population Dynamics Of Gloeotrichia Echinulata With Considerations Of Global Climate Change, Sarah Stamann

Masters Theses

Global climate change has been identified as a driver for increasing cyanobacteria blooms world-wide. Blooms of the cyanobacterium, Gloeotrichia echinulata, (hereafter, G. echinulata) have been observed in Silver Lake (Oceana County, MI), often forming dense surface scums. This organism is known to produce the hepatotoxin, microcystin- LR, and its growth is linked to phosphorus accumulation from sediment and temperature.

A series of experiments at ambient and elevated temperatures (+2° and +6°above ambient) with sediment from four locations in Silver Lake with varying phosphorus concentrations were conducted to examine the effect of these variables on G. echinulata growth. These …

Great Lake Island Biogeography Of Plethodon Cinereus: Effect Of Island Elevation On Color Polymorphism, Cameron N. Eddy

Masters Theses

Islands have long fascinated ecologists and evolutionary biologists because they provide replicated systems with which to test hypotheses regarding evolutionary and ecological theory. Because islands are relatively simple systems, they enable researchers to isolate specific factors responsible for observed phenomena. Many current questions in ecology and evolutionary biology have been addressed in island systems. For example, factors involved in the genetic divergence of populations are easier to discern in island populations because confounding effects of gene flow from adjacent populations are limited. This study focuses on isolated island populations of the color polymorphic Eastern Red-backed Salamander (Plethodon cinereus) …

Invasive Asian Earthworms Negatively Impact Woodland Salamanders: Competitive Exclusion, Foraging Interference, And Habitat Degradation Reduce Salamander Density, Julie L. Ziemba

Masters Theses

Asian earthworms (Amynthas spp.) are invading North American forests and consuming the vital detrital layer that forest floor biota (including the Eastern Red-backed Salamander, Plethodon cinereus) rely on for protection, food, and habitat. Salamander population decline has been associated with European earthworm-mediated leaf litter loss, but there have been few studies on the interactions between Amynthas spp. and P. cinereus. Since the large, active Amynthas spp. earthworms spatially overlap with salamanders beneath natural cover objects and in detritus, they may compound the negative consequences of resource degradation by physically disturbing important salamander activities (foraging, mating, and egg brooding). I predicted …

One Fish, Two Fish, Red Fish, Blue Fish: The Analysis Of The Specter Cell Cycle Mutant In Zebrafish, Tetiana Petrachkova

Masters Theses

Cell division is controlled by genes that regulate the cell cycle. Here we show that the zebrafish specter (spr) mutant is mutation in the cyclin B1 gene, a gene necessary for the G2 to M transition of the cell cycle.

The spr mutation mapped to the cyclin B1 gene. Sequencing showed a transition (C139→T) that caused a nonsense mutation in exon 2 of the cyclin B1 gene. In situ hybridization of cyclin B1 revealed that the mRNA is absent in the mutant embryo by gastrulation. We found that the earliest visible mutant phenotype was a darkening of the head caused …

Microbial Community Analysis From Petroleum-Contaminated Sediments With High Magnetic Susceptibility, Anja E. Williams

Masters Theses

Microbial biodegradation is an increasingly incorporated method of hydrocarbon mineralization during oil spill cleanup. To monitor biodegradation, magnetic susceptibility (MS) is a geophysical tool that detects changes in sediments’ magnetism, possibly caused by microbial activity, for example by anaerobic iron reduction that can induce magnetite formation. Furthermore, the high input of carbon from an oil spill makes other required nutrients, like nitrogen, limiting. The first study goal was to characterize the microbial communities present at high levels of MS with 16S rRNA gene clone libraries at the petroleum-contaminated site in Bemidji, Minnesota. Sequences with high similarity to known iron-reducers were …

Progressive Decline Of Testicular Function In Leptinreceptor Deficient Obese Mice, Jennifer Long

Masters Theses

The incidence of obesity and metabolic syndrome among the human population is increasing, but the effects on male fertility are unresolved. Leptin insensitivity appears to show a consistent relationship between obesity and fertility problems in men. Genetically modified mice lacking the leptin hormone (ob/ob) or leptin receptor (db/db) are reported to be subfertile and/or infertile but there is only minimal information about testicular function (sperm and hormone production) and the progression of infertility. Therefore, this study was designed to investigate testicular function using a leptin-receptor-deficient obese mouse model (the POUND mouse; Charles River). Testicular sperm production is reduced in POUND …

A Gravity Investigation Of The Tobacco Root Batholith Southwest Montana, Stephen Charles Tatum

Masters Theses

The objective of this research was to delineate and profile the Late Cretaceous Tobacco Root batholith in southwestern Montana through the application of the gravitational method. This survey was accomplished by obtaining 232 gravity measurements in four profiles across the batholith. After correcting for known variations in the gravity field, a Bouguer anomaly map of the batholith and surrounding host rocks was created. Four residual gravity profiles and map, created by subtracting the regional gravity from the Bouguer anomaly, reveal a maximum negative gravity anomaly in the center portion of the batholith which is parallel to the trend of the …

Exploring The Oncolytic Potentail Of A Double Knock-Out Tanapoxvirus Containing Flic Transgene, Esaw W. Kurban

Masters Theses

Since the emergence of oncolytic viruses (OVs), OVs have seen success in clinical trials and are a vital alternative treatment for cancer. Colorectal cancers are diseases which cause substantial health issues in the developed world, but current invasive treatment methods do not perform well in patients with advanced disease. We have explored the potential of tanapoxvirus (TPV) for its oncolytic virothrapy in two manners; specific gene deletion and non-targeted gene deletion. The non-targeted mutation of TPV’s genome was attempted using N-methyl-N-nitro-N-nitrosoguanidine (NTG) and N-ethyl-N-nitrosourea (ENU) as alkylating chemical. Specific gene deletion involved knocking-out a thymidine kinase gene (TPV-66R) and a …

The Effects Of Nitrogen Availability And Competition On First Year Perrennial Bunchgrass Growth And Allocation, Jeffrey T. Walker

Masters Theses

Improving seedling survival of perennial bunchgrasses is a key goal of restoration programs in the Intermountain West. Two perennial bunchgrass species commonly used in restoration programs (Agropyron desertorum and Pseudoroegneria spicata) were exposed to two levels of N and competition treatments in a randomized complete block study in a pot study in eastern Oregon. I documented uptake, allocation and resorption of N in plants during the first year of growth. Agropyron desertorum had significantly higher rates of N uptake than P. spicata, but A. desertorum maintained lower tissue N concentrations, suggesting that P. spicata was more likely to …

Female Mate Choice In A Mainland Population Of The Strawberry Poison Frog, Oophaga Pumilio, Meaghan Gade

Masters Theses

Sexual selection and female mate choice are driving forces in the evolution and maintenance of biological diversity, and may function in the evolution of many secondary sexual characteristics throughout multiple taxa. Female mate selection has been experimentally shown to drive the evolution of color between the polytypic populations of the dendrobatid frog, Oophaga pumilio, in the Bocas del Toro archipelago in Panama. However, limited studies exist examining biologically relevant female mate choices within a single population. Using analogous experimental arenas from previous studies, females were presented with two males exhibiting phenotypic extremes from within the same population at La Selva …

Computational Modeling Of Β5-Β6 Carbapenemase Loop In Wild Type And Selected Mutants Of Oxa-24 Class D Β-Lactamase, James Roland Lafleur

Masters Theses

Bacterial resistance to antibiotic therapies, especially to β-lactams, is an increasing problem. β-lactamases are the main source of clinical resistance to these antibiotics, and the class D β-lactamases are one of the most rapidly expanding classes of these enzymes. The emergence of class D enzymes with the ability to hydrolyze the newest family of β-lactams - the carbapenems - is a serious concern for the healthcare system as carbapenems are last resort antibiotics: ideal for severe infections after other therapies have failed. Class D β-lactamases are very diverse in terms of sequence and substrate profile, and it remains unclear what …

Evolution Of Invasive Species In Response To Management: Potential For Herbicide Resistance In Watermilfoil, Lindsey-Ann Louise Schulte

Masters Theses

Herbicides are commonly used to control invasive plants. While agricultural weed scientists have focused on herbicide resistance, little is known about its importance in nonagricultural settings. Hybrid Eurasian watermilfoil (Myriophyllum spicatum x M. sibiricum) is an invasive aquatic plant that is frequently managed with herbicides throughout the United States. In this thesis, I consider the potential for natural populations of this taxon evolving resistance to 2,4-dichlorophenoxyacetic acid (2,4-D), the most commonly used systemic herbicide. Evolutionary change in a trait between generations as a result of selection requires both genetically based variation of the trait within a generation (heritable …