Biology Commons^™

Evaluation Of Brook Trout (Salvelinus Fontinalis) Introductions And Re-Introductions Into Four Virginia Blue Ridge Mountain Streams, Michael Isel Iii

Theses and Dissertations

Approximately 100 brook trout were transplanted into each of four Virginia streams in September 2008. Garth Run and Kinsey Run were re-introductions, and Wildcat Hollow and Sweet Run were new introductions. Single pass electrofishing (EF) surveys were conducted with a backpack electrofisher five times during the study. Selected trout > 70 mm but < 100 mm and all trout > 100 mm received a Biomark® 134.2 kHz passive integrated transponder (PIT) tag to identify individual fish upon recapture. Trout were present in all streams almost three years post introductions. Catches decreased across the first four surveys. Young of year catch rates severely decreased from June 2009 (n = …

Factors Controlling Dissolved Organic Carbon Lability And Ecological Fate In The East Branch Swift River, Massachusettes, Hall Eric

Theses and Dissertations

Fluvial systems have been estimated to transform, transport, or store 2.75 petagrams (Pg) of Organic Carbon (OC) per year. Although approximately 1Pg per year of terrestrial carbon is fluxed to the atmosphere through inland waters, little is known about the factors regulating its eventual ecological fate. 28 day lability incubations were conducted concurrent with the measurement of several environmental parameters including discharge, nutrient concentration, DO13C, and DOC:DON at several sites along Bigelow Brook and the East Branch of the Swift River, Massachusetts. Temporal and spatial variation of DOC, DOC:DON and DO13C were explored. Two distinct DOC consumption rates, short and …

Shrubs As Sentinels Of Ordnance Contamination: Using Plant Physiology And Remote Sensing To Detect Tnt In Soils, Kathryn Rubis

Theses and Dissertations

Methods for rapid, safe and effective detection of unmapped buried ordnance are vital to the protection of humans and environmental quality throughout the world. This study aimed to investigate the use of phytosensing and to understand the physiological response of woody plants to 2,4,6-trinitrotoluene (TNT) contamination. Baccharis halimifolia were potted in soils containing various concentrations of TNT and physiological responses were observed over a 9-week experimental period. Measurements included the collection of remotely sensed data, such as hyperspectral reflectance and chlorophyll fluorescence, and traditional plant-level physiological data. In accordance with the hypothesis, low levels of TNT improved physiological response in …

Composition Of Suspended And Benthic Particulate Matter In The Tidal Freshwater James River, Anne Schlegel

Theses and Dissertations

Investigating linkages between the compositions of suspended (seston) and benthic particulate matter is important to the understanding of organic matter (OM) cycling and nutrient retention in aquatic systems. We compared the quantity and quality of the truly suspended (TS) and settleable (SB) fractions of seston as well as benthic particulate matter in the tidal freshwater James River, Virginia. The mass of seston and OM was consistently higher in the TS fraction compared to the SB fraction. OM was preferentially retained in the TS fraction relative to seston. The proportional contribution of OM constituents (chlorophyll a, particulate organic carbon and nitrogen) …

The Abundance And Infection Status Of Anopheles Spp. Mosquitoes At Three Sites In Loudoun County, Northern Virginia, Priya Krishnan

Theses and Dissertations

Malaria is a re-emerging infectious disease with approximately half of the world's population at risk. In the US, since the 1950’s the Center for Disease Control (CDC) has been reporting between 1,000 and 1,500 cases of malaria every year. A majority of these cases were among US travellers and were attributed to Plasmodium falciparum. In August 2002, two cases of human malaria due to Plasmodium vivax were reported in Loudoun County, Northern Virginia. The Center for Disease Control and Prevention concluded that these cases were acquired locally. This was because of an absence of other risk factors such as international …

Legacy Sediments In Streams - Effects On Nutrient Partitioning During Simulated Re-Suspension Events., Molly Sobotka

Theses and Dissertations

Anthropogenic inputs of nutrients and sediment are a widespread problem in U.S. streams causing localized impairment and contributing to eutrophication of coastal habitats. Sediments and dissolved nutrients interact through diverse processes including ion exchange, sorption and biotic assimilation by particle-bound bacteria. This study examined the effects of sediment re-suspension on nutrient partitioning in lab microcosms using fine benthic matter collected from two Virginia Coastal Plain streams. Kimages Creek was recently restored following dam removal and was characterized by large deposits of legacy sediments. Courthouse Creek was characterized by sandy substrates typical of Coastal Plain streams. Sediment characteristics differed between the …

Characterizing The Distribution Of Planktonic Fecal Bacteria In The James River, Richmond, Virginia, John Furry

Theses and Dissertations

Surface waters containing fecal bacteria present significant public health risks. Understanding the sources of and factors affecting the distribution of fecal-indicating bacteria is necessary to predict potential illnesses more effectively. This thesis presents two studies on the distribution of fecal bacteria in the James River through Richmond, Virginia. Chapter 1 describes nearly 11 years of water quality, climate, and hydrologic data that occurred with changes in Escherichia coli concentrations, concluding that Richmond contributes significant quantities of fecal bacteria to the James River, and that the distribution of these bacteria varies seasonally. Chapter 2 details the development of Polymerase Chain Reaction …

Morphology, Material And Vibratory Properties Of The Swimbladder In The Carp, Cyprinus Carpio, Yasha Mohajer

Theses and Dissertations

The carp Cyprinus carpio has a two-chambered swimbladder and excellent hearing. I explored the hypothesis that the anterior chamber, which connects to Weberian ossicles, is adapted for hearing by testing both chambers for material properties. I also determined displacement and auditory responses to mechanical strikes. Wall stress is higher in the posterior, strain in the anterior and modulus lower in the anterior chamber. Strikes increase pressure followed by a variable rebound that rapidly decays. Displacement and sound amplitude increase with hammer force, and amplitude is similar in both chambers for within chamber strikes but lower across chambers. Normalized for equivalent …

Novel Methodology For Assessing Phytoplankton Response To Pco2 Enrichment In Fresh And Saltwater, Susan B. Gifford

Theses and Dissertations

Atmospheric CO2 emissions are on the rise and are expected to reach 780 parts per million by the year 2100. Research investigating the impacts of increasing CO2 is a relatively new field and the response of phytoplankton communities is largely unknown, especially in coastal and freshwater ecosystems where no CO2 manipulation studies have completed. The present study attempts to encourage uniformity in methods utilized in CO2 perturbation studies and identifies changes in phytoplankton abundance in freshwater (James River) and coastal ocean (Atlantic, Cape Hatteras) sites. A novel bubbling method to manipulate pCO2 was compared with the classic method of acid …

Investigation Of Pre- And Post-Zygotic Reproductive Barriers Between Two Host-Plant Complex Races Of The Parasitic Wasp Cotesia Congregata (Say) [Hymenoptera: Braconidae], Justin Bredlau

Theses and Dissertations

Investigations of host-associated differentiation of parasitoids have largely focused on the degree of molecular genetic differentiation, but a true test of species status must examine the mating patterns of differentiated populations to determine if they can interbreed in the wild and produce viable offspring. We examined possible mechanisms of isolation between two genetically distinct host-plant complex races of the braconid, Cotesia congregata, originating from hosts on tobacco and catalpa. We compared male responses to female pheromones, elements of male acoustic courtship signals, and breeding success between the two races. Males responded to pheromones from both sources and male courtship signals …

Changes In Leaf Morphology, Photosynthesis And Nitrogen Content In Two Coastal Shrubs, Elizabeth Kost

Theses and Dissertations

It is important to understand mechanisms that facilitate expansion of two common shrubs, Morella cerifera and Baccharis halimifolia in coastal environments. The purpose of my study was to investigate the physiological and structural changes that occur as leaves age. Photosynthesis, incident light, chlorophyll, and leaf C:N ratios were quantified for young, intermediate, and old leaves (distal, central and proximal leaves, respectively). Leaf structural differences were also compared. Leaves did not change morphologically with age. Light decreased with leaf age and during winter months. Photosynthesis showed no seasonal or age related patterns. Chlorophyll increased initially and then declined with age due …

Exploring The Functional Interaction Between Camk-Ii And P53, Raymond Lai

Theses and Dissertations

Calcium (Ca2+)/calmodulin-dependent kinase 2 (CaMK-II) is a multifunctional member of a family of Ca2+/calmodulin-dependent serine/threonine protein kinases that respond to transient intracellular calcium signaling. CaMK-II has been reported to be involved with transcription regulation, cell motility, neuronal development, cell cycle regulation, and more recently early development of vertebrates (Easley et al., 2008; Rothschild et al., 2009; Francescatto et al., 2010). Through previous work in the lab using tandem mass spectrometry and “substrate-trapping mutants”, tumor suppressor protein 53 (p53) was identified as a novel CaMK-II binding partner in tissue culture. In this study, I sought to provide characterization of the functional …

Behavior And Development Of Red-Eyed Treefrogs During Metamorphosis [Poster], Robin Greene, Clay Noss, Tobias Lanberg, James R. Vonesh, Karen Warkentin

Biology Presentations

Anuran metamorphosis is an extreme transformation from tadpole to frog that involves tremendous morphological and behavioral change. During this transition (Gosner stages 42-46), metamorphs are exposed to both aquatic and terrestrial selective pressures (e.g., predators, desiccation). Their behavior may be crucial for survival, but it is not well studied. Our goal was to describe morphological and behavioral patterns during metamorphosis in red-eyed treefrogs, Agalychnis callidryas. We first quantified development through metamorphosis by measuring and staging 25 wild-caught individuals every 8 h. We then conducted field behavioral observations of 37 metamorphs, at various developmental stages, that had emerged from a …

The Cost Of Hatching Early: Vulnerability And Exposure To Predators [Poster], M. S. Palmer, B. Willink, T. Landberg, James R. Vonesh, K. M. Warkentin

Biology Presentations

Arboreal red-eyed treefrog embryos can hatch prematurely in response to egg predators. Induced early hatchlings face aquatic predators when less developed and for longer than do later hatchlings; both factors may alter survival through the high-risk early larval period. Prior work focused on developmental effects of induced hatching. In 24 h trials, less developed hatchlings were more vulnerable to three aquatic predators (shrimp, fish, water bugs) but had similar or better survival than full-term hatchlings with libellulid and aeschnid dragonfly nymphs. However, it is unknown how developmental effects and duration of exposure to predators combine to create the net effect …

Habitat Use And Population Densities Of Rain Forest Chameleons In The East Usambara Mountains Of Tanzania [Poster], Philip Shirk, David A. Patrick, James R. Vonesh, Kim Howell

Biology Presentations

Conclusions:

• Chamaeleo dilepis and Ri. brevicaudatus are absent from forest at this elevation (852-1103m), while K. matschiei, K. vosseleri, K. tenuis, and R. spinosus are relatively scarce in the forest. Trioceros deremensis and R. temporalis are common, but density varies greatly.
• The endemic and scarce K. matschiei and K. vosseleri may be of concern given their scarcity in forest habitat. Density estimates in other habitat types are needed to determine status.
• For accurate density estimates, it is important to consider seasonal variation in density and animals too high to be observed in surveys.

Tadpole Density Changes The Relationship Of Red-Eyed Treefrog Morphology And Jumping Performance [Poster], Julie Charbonnier, T. Landberg

Biology Presentations

As organisms develop, increased body size is often accompanied by shape changes that alter the morphology–performance relationship. Animals with different growth histories may also have different shapes at similar body sizes. To investigate how larval growth history affects the morphology–performance relationship, we raised red-eyed treefrog tadpoles (Agalychnis callidryas) at three densities (5, 25 and 50 tadpoles per 400 L tank) and measured jump distance during metamorphosis. We predicted that tadpoles grown at low density would metamorphose into larger frogs with relatively longer legs than those grown at higher densities. We also expected low density frogs to jump further …

Effects Of Hatching Timing On Red-Eyed Treefrog Tadpoles: Relative Vulnerability Varies Among Predators But Not With Hatchling Age-Structure, Growth Varies With The Presence Of More Vulnerable Tadpoles [Poster], B. Willink, T. Landberg, James R. Vonesh, K. M. Warkentin

Biology Presentations

In Gamboa, Panama, undisturbed red-eyed treefrog embryos typically hatch at age 6 days, but they can hatch as early as 4 days if attacked by egg predators. Early hatchlings are less developed and more vulnerable to predatory shrimp and fish. Here we assess the effect of hatching timing on risk of predation by three common insects, with different foraging styles, that prey on red-eyed treefrog larvae. Further, we examine whether the consequences of hatching early vary with the presence of later-hatched tadpoles. We induced hatching at 4 and 6 days and exposed tadpoles to giant water bugs or aeshnid or …

An Intermediate In The Evolution Of Superfast Sonic Muscles., Hin-Kiu Mok, Eric Parmentier, Kuo-Hsun Chiu, Michael L. Fine

Biology Publications

Background

Intermediate forms in the evolution of new adaptations such as transitions from water to land and the evolution of flight are often poorly understood. Similarly, the evolution of superfast sonic muscles in fishes, often considered the fastest muscles in vertebrates, has been a mystery because slow bladder movement does not generate sound. Slow muscles that stretch the swimbladder and then produce sound during recoil have recently been discovered in ophidiiform fishes. Here we describe the disturbance call (produced when fish are held) and sonic mechanism in an unrelated perciform pearl perch (Glaucosomatidae) that represents an intermediate condition in the …

Morphometric And Genetic Variation Among Populations Of The Southern Short-Tailed Shrew, Blarina Carolinensis, Located Along The Coastal Plain Of Virginia, Devon Kersten

Theses and Dissertations

The distribution of short-tailed shrews, Blarina carolinensis and B. brevicauda, demonstrates contiguous allopatry in peninsular situations in the Coastal Plain of Virginia, and in other areas. The distribution of these two species is unusual in that they do not exhibit syntopy except within a narrow corridor along the borders of their ranges. Interestingly, along the Coastal Plain of Virginia, B. carolinensis is generally found only at the distal ends of the peninsular areas, existing as local populations that appear to be isolated from each other and from the primary population that exists in south-central Virginia. It is thought that the …

Determining Impediments To Gene Flow In A Natural Population Of Cornus Florida L. Cornaceae, Using Integrative Landscape Genetic Techniques, Crystal Meadows

Theses and Dissertations

This study examined the impact intervening environment has on gene flow in the insect pollinated understory tree, Cornus florida L., by combining GIS and landscape genetic techniques (Least Cost Path Analysis, Circuit Theory, and Conditional Genetic Distance). Traditional population genetic analysis indicated pair-wise relatedness was significantly correlated to distance (Pearson; r = -0.312, P < 0.001) suggesting a spatial component to offspring relatedness. Dispersal throughout the study site was non-random, exhibiting a high degree of pollen pool structure due to restricted gene flow (Two-Generation Analysis; Φft = 0.161, P = 0.001). Forest structure was quantified in GIS layers representing coniferous canopies, mixed hardwood canopies, C. florida canopies, open understory (roads), and open understory/canopy due to tree removal. Of these layers, landscape isolation for the roads layer provided the best-fit model for describing genetic differentiation among sampled pollen pools (Mantel; r = 0.542, P = 0.001). These data also suggest that improved biological inferences can be gained by examining a range of landscape isolation models.

Head-Start Juvenile And Adult Resident Eastern Box Turtles (Terrapene Carolina Carolina): Winter Ecology Including Microhabitat Selection, Temperature Tolerance And Philopatry, Amberly Moon

Theses and Dissertations

The Eastern box turtle (Terrapene carolina carolina) is one of the most common reptiles in North America, but is soon to be threatened due to increased urbanization, disease, and the pet and food trades. In order to assist resource managers in choosing suitable sites for relocation studies, more information on the winter ecology of this species is necessary. We examined the temperature tolerance, microhabitat and degree of philopatry to hibernacula for juvenile and adult E. box turtles for two consecutive winters in Charles City Co, VA. The turtles were tracked via radio telemetry to record point locations during the active …

Distribution And Molecular Analysis Of Avian Malaria Vectors On Four Central Virginia Prothonotary Warbler (Protonotaria Citrea) Breeding Sites, Catherine Wallace

Theses and Dissertations

Avian malaria is a devastating disease that has decimated numerous bird species. This study sought to identify the vectors of avian malaria at four central Virginia Prothonotary warbler breeding sites. Twenty one thousand mosquitoes were collected and Culex salinarius, Cx. erraticus, and Cx. pipiens/restuans were found to be the dominant species at these sites. Geographic factors, such as crop land and forest type, were determined to be potential indicators for species abundance variation between sites. Of the mosquitoes collected, ninety one (0.4%) were identified as blood fed. The blood fed mosquitoes were found to have fed on avian, mammalian, amphibian, …

Depth And Time Related Variations Of Microbial Communiites In An Emergent Freshwater Wetland, Amy Jenkins

Theses and Dissertations

Soils, and the microbial communities contained within them, are vital for most chemical, physical, and biological processes. This study investigated how microbial community structure responded to environmental changes, such as hydrology, across vertical space (depth) and time in an emergent fresh water wetland. Research was conducted in a non-tidal freshwater wetland along the James River (Charles City County, Virginia) by establishing plots in two areas that experienced different hydrologic regimes and plant communities. Soil cores (30 cm) were collected monthly from January 2008 to February 2009, and then every two to three months thereafter until October 2009, for a total …

Canopy Disturbance And Reproduction In Cornus Florida L., Daniel Carr

Theses and Dissertations

This study examined aspects of local reproductive variation in the flowering dogwood (Cornus florida L.) coincident with recent differences in primary canopy architecture. The dogwood trees in this study were impacted by a hurricane that created numerous treefall gaps, which created fine scale heterogeneity in the primary canopy. Fine scale disturbances in a forest can result in changes for multiple members of the forest community, including the reproductive responses of the trees and interspecific pollination mutualisms. Previously determined differences in offspring genetic structure suggested that pollen movement among genetically unstructured maternal individuals was significantly impacted between open, or disturbed, canopy …

Effect Of Ph On The Transcriptional Profile Of Porphyromonas Gingivalis W83, Nathan Maietta

Theses and Dissertations

Porphyromonas gingivalis, a gram-negative, anaerobic bacterium, is widely recognized as a causative agent for periodontal disease. Despite sequencing of the complete genome, no research exists examining gene regulation response in P. gingivalis to shifts in pH. Previous studies have shown that P. gingivalis is capable of surviving in the variety of micro- environmental niches found within the oral cavity, including basic and acidic pH conditions. However, the underlying mechanisms of this survival are not well understood. This study examined P. gingivalis by comparing bacteria shocked at three acidic to neutral pH conditions (5.5, 6.5 and 7.0) to bacteria vii shocked …

Variation In Sound Production Of The Blue Catfish, Ictalurus Furcatus., Zachary Ghahramani

Theses and Dissertations

The blue catfish, Ictalurus furcatus, is an invasive species introduced to Virginia in 1974 and is the largest catfish in the United States. Like other Ictalurids, they are capable of producing disturbance calls via stridulation of the pectoral spine. These sounds can be made in air and water, and catfish can be preyed upon by both aerial and underwater predators. I characterized these putative distress calls by recording them in air and in the fish’s natural habitat. Sounds exhibited a wide variation in acoustic parameters relative to fish ontogeny: larger fish produced higher amplitude sounds with lower frequency bands. Sweep …

Evolutionary Relationships In Afro-Malagasy Schefflera (Araliaceae) Based On Nuclear And Plastid Markers, Morgan Gostel

Theses and Dissertations

The genus Schefflera is the largest in Araliaceae, with approximately 900 species. Recent studies have shown that Schefflera is polyphyletic and represents no fewer than five distinct clades, each corresponding to a specific geographic region including Asia, continental Africa and Madagascar, Melanesia, the Neotropics, and a small clade distributed throughout several islands in the insular Pacific Ocean. The Afro-Malagasy clade contains nearly 50 species distributed throughout tropical, sub-Saharan Africa, Madagascar, the Comoros, and the Seychelles islands. Previous studies have suggested that this group is monophyletic, identifying two smaller subclades within Afro-Malagasy Schefflera corresponding roughly to informal groups identified as “Meiopanax” …

The Effects Of Hydrology And Vegetation On Microbial Community Structure And Soil Function In The Sediments Of Freshwater Wetlands, Christine Prasse

Theses and Dissertations

In wetland soils, hydrology is considered to be one of the primary factors shaping wetland function and microbial community structure, but plant-soil interactions are also important mechanisms affecting microbial nutrient transformations. The research presented here considered the interactive effect to describe how hydrology and the presence of plants alter the soil profile, the development of the bacterial community, and their associated functions. To achieve this goal, plots were established in three hydrologically-distinct regimes (Wet, Intermediate, and Dry) within a non-tidal freshwater wetland along the James River (Charles City County, Virginia). Inside each main plot, ten subplots were cleared of all …

Effects Of Alternative Prey As A Buffer To Predation Of Channel Catfish (Ictalurus Punctatus) By Largemouth Bass (Micropterus Salmoides), Shelley Nellis

Theses and Dissertations

Channel catfish have pectoral spines that lock to defend against gape-limited predators such as largemouth bass. Previous work indicated that spines increase survival of channel catfish exposed to bass but did not determine whether bass avoid catfish if less dangerous species are available. We presented bass with channel catfish and two alternatives, bluegill and goldfish, and compared order of ingestion, ingestion time, percent of successful strikes, and time spent chasing each prey species. We also presented the three species in a jar study that standardized position in the water column as well as in a net-pen study. The order of …

Factors Influencing The Abundance, Community Composition And Activity States Of Bacterioplankton From The Tidal Freshwater James River, Catherine Luria

Theses and Dissertations

Aquatic bacteria respond to changing environmental conditions through a variety of mechanisms including changes in abundance, shifts in community composition and variable activity states. In the tidal-freshwater James River, variation in bacterial abundance was linked to nutrient availability and autochthonous production with highest bacterial densities associated with low-nutrient, high-chlorophyll a conditions. Laboratory experiments revealed that bacterial growth rates were nutrient limited at the low-nutrient site, while co-limitation (nutrients, glucose, light) was apparent at the high nutrient site. Despite large differences in abundance, community composition was similar based on TRFLP and 16S rDNA pyrosequencing. Community similarity was lower among rRNA libraries …