Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 27 of 27

Full-Text Articles in Life Sciences

Sublethal Effects Of Methylmercury On The Songbird Immune Response: An Experimental Study, Catherine Ann Lewis Jan 2012

Sublethal Effects Of Methylmercury On The Songbird Immune Response: An Experimental Study, Catherine Ann Lewis

Dissertations, Theses, and Masters Projects

No abstract provided.


Spe-7, A Novel Regulator Of Msp Assembly In C Elegans Spermatocytes, Kari Lynn Messina Jan 2012

Spe-7, A Novel Regulator Of Msp Assembly In C Elegans Spermatocytes, Kari Lynn Messina

Dissertations, Theses, and Masters Projects

No abstract provided.


Effects Of Anthropogenic Stressors And Changes In Biodiversity On Lower Chesapeake Bay, Va Usa Seagrass Systems, Rachael E. Blake Jan 2012

Effects Of Anthropogenic Stressors And Changes In Biodiversity On Lower Chesapeake Bay, Va Usa Seagrass Systems, Rachael E. Blake

Dissertations, Theses, and Masters Projects

Anthropogenic stressors are increasingly changing conditions in coastal areas and impacting important habitats. But, when multiple stressors act simultaneously, their effects on ecosystems become more difficult to predict. In Chesapeake Bay, USA, predictions suggest that anthropogenic stressors from climate change, such as warming temperatures, may increase the frequency and severity of storm events, leading to increased freshwater, nutrient, and sediment inputs. Coastal development, another source of anthropogenic stressors, continues to increase with growing coastal populations, and may lead to altered sediment characteristics, habitat fragmentation, altered food webs, and loss of vegetated habitats. Community processes may interact with stressors, for example ...


Positive And Negative Feedbacks Within Zostera Marina Beds Within The Chesapeake Bay, Virginia, Lance M. Gardner Jan 2012

Positive And Negative Feedbacks Within Zostera Marina Beds Within The Chesapeake Bay, Virginia, Lance M. Gardner

Dissertations, Theses, and Masters Projects

Particulate levels within marine, estuarine and freshwater vegetated shallows are often lower than in nearby open water, although most of the studies quantifying this trend are from non-tidal, freshwater systems. The potential positive feedbacks between vegetation, water clarity, and zooplankton clearance and the potential negative feedback from microbially-mediated sulfide production were investigated in several eelgrass (Zostera marina) beds in the lower York River and Mobjack Bay, Chesapeake Bay, Virginia and through the construction of a computer simulation model. Paired automated chlorophyll a and turbidity sensors were deployed for eight one-week periods to compare particulate levels inside and outside of eelgrass ...


Interannual And Regional Differences In Krill And Fish Prey Quality Along The Western Antarctic Peninsula, Kate E. Ruck Jan 2012

Interannual And Regional Differences In Krill And Fish Prey Quality Along The Western Antarctic Peninsula, Kate E. Ruck

Dissertations, Theses, and Masters Projects

Polar zooplankton and fish safeguard against the seasonality of food availability by using the summer months to build large reserves of lipids, which in turn are utilized to meet the metabolic demands of apex predators such as penguins, seals, and whales. A warming trend in the northern part of the western Antarctic Peninsula (WAP) has led to a decrease in perennial and summer sea ice, an increase in heat content over the shelf, and lower phytoplankton biomass, which could affect prey quality. We compared prey quality, including elemental (C, N) content and ratios, total, neutral, and polar lipid content, and ...


Distribution And Feeding Ecology Of Bathylagus Euryops (Teleostei: Microstomatidae) Along The Northern Mid-Atlantic Ridge From Iceland To The Azores, Christopher J. Sweetman Jan 2012

Distribution And Feeding Ecology Of Bathylagus Euryops (Teleostei: Microstomatidae) Along The Northern Mid-Atlantic Ridge From Iceland To The Azores, Christopher J. Sweetman

Dissertations, Theses, and Masters Projects

The northern Mid-Atlantic Ridge, from Iceland to the Azores (MAR), ranges in depth from 800 – 4500 m and extends over an area of 3.7 million km2. Recent evidence from MAR-ECO, a Census of Marine Life field project, reported increased abundance and biomass of deep-pelagic fishes below 1000 m on the MAR. Among the fishes sampled, Bathylagus euryops was found to be the biomass-dominant species and ranked third in total abundance. In this thesis, we characterize the distribution and feeding ecology of B. euryops as a function of physical, biological, and life history parameters along a mid-ocean ridge system. Multiple ...


Evaluating Persistent Organic Pollutants (Pops) And Mercury In The West Antarctic Peninsula (Wap) Food Web, With A Focus On Antarctic Fur Seals (Arctocephalus Gazella), Emily K. Brault Jan 2012

Evaluating Persistent Organic Pollutants (Pops) And Mercury In The West Antarctic Peninsula (Wap) Food Web, With A Focus On Antarctic Fur Seals (Arctocephalus Gazella), Emily K. Brault

Dissertations, Theses, and Masters Projects

No abstract provided.


Unprecedented Restoration Of A Native Oyster Metapopulation, David M. Schulte Jan 2012

Unprecedented Restoration Of A Native Oyster Metapopulation, David M. Schulte

Dissertations, Theses, and Masters Projects

No abstract provided.


The Effects Of Salinity Pulses Of Varying Duration And Intensity On Three Freshwater Submerged Aquatic Vegetation Species, Rebecca Wright Jan 2012

The Effects Of Salinity Pulses Of Varying Duration And Intensity On Three Freshwater Submerged Aquatic Vegetation Species, Rebecca Wright

Dissertations, Theses, and Masters Projects

No abstract provided.


Sexual Dimorphism, Diet, And Body Condition Of Rusty Blackbirds Wintering In Virginia, Andrew John Mcgann Jan 2012

Sexual Dimorphism, Diet, And Body Condition Of Rusty Blackbirds Wintering In Virginia, Andrew John Mcgann

Dissertations, Theses, and Masters Projects

No abstract provided.


Pax5 Signatures: The Identification Of Pax5 Isoforms In Developing And Activated B Cell Populations Of Rainbow Trout, Elizabeth Anne Macmurray Jan 2012

Pax5 Signatures: The Identification Of Pax5 Isoforms In Developing And Activated B Cell Populations Of Rainbow Trout, Elizabeth Anne Macmurray

Dissertations, Theses, and Masters Projects

No abstract provided.


Transcriptional Regulation Of The Acetone Carboxylase Operon Via Two-Component Signal Transduction In Helicobacter Pylori, Vanessa H. Quinlivan-Repasi Jan 2012

Transcriptional Regulation Of The Acetone Carboxylase Operon Via Two-Component Signal Transduction In Helicobacter Pylori, Vanessa H. Quinlivan-Repasi

Dissertations, Theses, and Masters Projects

No abstract provided.


Microburst Damage Assessment And Forest Composition Reconstruction After Hurricane Isabel In The College Woods, Williamsburg, Va, Kjarstin Alane Carlson-Drexler Jan 2012

Microburst Damage Assessment And Forest Composition Reconstruction After Hurricane Isabel In The College Woods, Williamsburg, Va, Kjarstin Alane Carlson-Drexler

Dissertations, Theses, and Masters Projects

No abstract provided.


Movements, Growth, And Mortality Of Chesapeake Bay Summer Flounder Based On Multiple Tagging Technologies, Mark J. Henderson Jan 2012

Movements, Growth, And Mortality Of Chesapeake Bay Summer Flounder Based On Multiple Tagging Technologies, Mark J. Henderson

Dissertations, Theses, and Masters Projects

The research projects presented in this dissertation used multiple tagging technologies to examine the movements, growth, and mortality rates of summer flounder tagged and released in Chesapeake Bay. In the first two chapters, I used acoustic, archival, and conventional tags to examine the behavior of summer flounder on different spatial scales. Investigating the movement behavior of individuals on different scales is an important step towards understanding how large-scale distributions of a population are established. Based on the observed behaviors of summer flounder, I hypothesize that the movements of these fish are primarily related to foraging behavior while they are resident ...


Patterns Of Population Structure And Historical Dispersal In Squaloid Sharks: A Species-Level Approach Using Molecular Markers, Ana Christina Pimenta Verissimo Jan 2012

Patterns Of Population Structure And Historical Dispersal In Squaloid Sharks: A Species-Level Approach Using Molecular Markers, Ana Christina Pimenta Verissimo

Dissertations, Theses, and Masters Projects

Squaloids (Order Squaliformes) are a highle diverse group of mostly deepwater habitats (> 200 m). Many species are regularly caught in commercial fisheries worldwide but their low productivity and correspondingly low intrinsic rebound potentials make them particularly vulnerable to population depletion and overexploitation. of special concern to fisheries management and conservation efforts are the spiny dogfish Squalus acanthias, the leafscale gulper shark Centrophorus squamosus and the Portuguese dogfish Centroscymnus coelolepis. These taxa have recently been declared overfished in several parts of each species' distribution but management efforts have been made to recover the "stocks" without a good understanding of the species ...


A Case Study In The Effectiveness Of Marine Protected Areas (Mpas): The Islands Of Bonaire And Curacao, Dutch Caribbean, Noelle J. Relles Jan 2012

A Case Study In The Effectiveness Of Marine Protected Areas (Mpas): The Islands Of Bonaire And Curacao, Dutch Caribbean, Noelle J. Relles

Dissertations, Theses, and Masters Projects

The islands of Bonaire and Curacao, Dutch Caribbean, were both mapped along their leeward coasts for dominant coral community and other benthic cover in the early 1980s. This mapping effort offers a unique baseline for comparing changes in the benthic community of the two islands since that time, particularly given the marked differences between the two islands. Bonaire is well-protected and completely surrounded by a marine protected area (MPA), which includes two no-diving marine reserves; additionally, Bonaire's population is only around 15,000. In contrast, the island of Curacao is home to 140,000 inhabitants and marine protection is ...


Age-Related Changes In The Neural Correlates Of Interval Timing, Cutter Augustus. Lindbergh Jan 2012

Age-Related Changes In The Neural Correlates Of Interval Timing, Cutter Augustus. Lindbergh

Dissertations, Theses, and Masters Projects

No abstract provided.


Myctophid Feeding Ecology And Carbon Transport Along The Northern Mid-Atlantic Ridge, Jeanna M. Hudson Jan 2012

Myctophid Feeding Ecology And Carbon Transport Along The Northern Mid-Atlantic Ridge, Jeanna M. Hudson

Dissertations, Theses, and Masters Projects

The Mid-Atlantic Ridge (MAR) is the largest topographic feature in the Atlantic Ocean, yet little is known about the food web structure and trophic ecology of fishes inhabiting mesopelagic waters along the MAR. To better understand the food web structure and to compare the feeding ecology of abundant MAR fishes to those in offridge areas, MAR-ECO, a Mid-Atlantic Ridge ecosystem field project of the Census of Marine Life, sampled the pelagic fauna of the northern MAR (Iceland to the Azores) during June-July, 2004. Samples were collected with two midwater trawls outfitted with multiple opening and closing cod ends to sample ...


Microzooplankton Community Structure And Grazing Impact Along The Western Antarctic Peninsula, Lori M. Price Jan 2012

Microzooplankton Community Structure And Grazing Impact Along The Western Antarctic Peninsula, Lori M. Price

Dissertations, Theses, and Masters Projects

Microzooplankton (zooplankton 20 – 200 μm) are an integral part of aquatic food webs as they can be significant grazers of phytoplankton and bacteria, remineralizers of nutrients, and prey for higher trophic levels. The importance of microzooplankton in many pelagic ecosystems has been established, yet compared to larger zooplankton, microzooplankton are understudied in the Southern Ocean. I quantified microzooplankton community composition and grazing rates along the Western Antarctic Peninsula (WAP) as part of the Palmer Antarctica Long-Term Ecological Research project (PAL LTER). This region is experiencing rapid warming, causing declines in sea ice and changes in the marine food web. I ...


Shedding Light On The Estuarine Coastal Filter: The Relative Importance Of Benthic Macroalgae In Shallow Photic Systems, Johnathan Daniel Maxey Jan 2012

Shedding Light On The Estuarine Coastal Filter: The Relative Importance Of Benthic Macroalgae In Shallow Photic Systems, Johnathan Daniel Maxey

Dissertations, Theses, and Masters Projects

No abstract provided.


Seed Burial In The Seagrass Zostera Marina: The Role Of Infauna, Natalia J. Blackburn Jan 2012

Seed Burial In The Seagrass Zostera Marina: The Role Of Infauna, Natalia J. Blackburn

Dissertations, Theses, and Masters Projects

In terrestrial systems, seed burial is widely recognized as a vital process that influences small- and large-scale plant population patterns. Despite its demonstrated importance in terrestrial literature, very little is known about seed burial in seagrasses. Zostera marina is a perennial seagrass found in northern temperate oceans worldwide, and is the dominant seagrass found in the Chesapeake Bay. In terrestrial systems, seed burial is frequently mediated by soil-dwelling invertebrates. The goal of this work was to determine the role that benthic infauna play in the burial of Z. marina seeds by addressing the following questions: 1. Are seeds on sediments ...


Mobile Animals As A Potential Dispersal Mechanism In Zostera Marina (Eelgrass), Sarah E. Sumoski Jan 2012

Mobile Animals As A Potential Dispersal Mechanism In Zostera Marina (Eelgrass), Sarah E. Sumoski

Dissertations, Theses, and Masters Projects

No abstract provided.


Automated Reductions Of Markov Chain Models Of Calcium Release Site Models, Yan Hao Jan 2012

Automated Reductions Of Markov Chain Models Of Calcium Release Site Models, Yan Hao

Dissertations, Theses, and Masters Projects

Markov chain models have played an important role in understanding the relationship between single channel gating of intracellular calcium (Ca2+) channels, specifically 1,4,5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs), and the stochastic dynamics of Ca2+ release events, known as Ca2+ puffs and sparks. Mechanistic Ca2+ release site models are defined by the composition of single channel models whose transition probabilities depend on the local calcium concentration and thus the state of the other channels. Unfortunately, the large state space of such compositional models impedes simulation and computational analysis of the whole cell Ca2+ signaling in which the stochastic ...


Thermochemistry Of Amino Acids And Constrained Diamines, Erica Jane Tullo Jan 2012

Thermochemistry Of Amino Acids And Constrained Diamines, Erica Jane Tullo

Dissertations, Theses, and Masters Projects

The gas-phase proton affinities of several highly basic amino acids and diamines were determined using the extended kinetic method in an ESI-quadrupole ion trap instrument. The non-protein amino acid L-canavanine is structurally related to L-arginine with an oxygen substituted for the terminal methylene group of L-arginine and is highly toxic to humans. The proton affinity of L-arginine, a protein amino acid, was determined to be 1036 kJ mol -1, whereas the proton affinity of L-canavanine was determined to be 1005 kJ mol-1. Thus, substitution of an oxyguanidino group for the guanidine group in L-arginine results in a large decrease in ...


Physiological And Morphological Characterization Of Genetically Defined Classes Of Interneurons In Respiratory Rhythm And Pattern Generation In Neonatal Mice, Maria Cristina De Guzman Picardo Jan 2012

Physiological And Morphological Characterization Of Genetically Defined Classes Of Interneurons In Respiratory Rhythm And Pattern Generation In Neonatal Mice, Maria Cristina De Guzman Picardo

Dissertations, Theses, and Masters Projects

Breathing in mammals depends on an inspiratory-related rhythm that is generated by glutamatergic neurons in the preBotzinger complex (preBotC), a specialized site of the lower brainstem. Rhythm-generating preBotC neurons are derived from a single lineage that expresses the transcription factor (TF) Dbx1, but the cellular mechanisms of rhythmogenesis remain incompletely understood. to elucidate these mechanisms we comparatively analyzed Dbx1-expressing neurons (Dbx1 +) and Dbxl- neurons in the preBotC in knock-in transgenic mice. Whole-cell recordings in rhythmically active newborn mouse slice preparations showed that Dbx1 + neurons activate earlier in the respiratory cycle and discharge greater magnitude inspiratory bursts compared to Dbxl - neurons ...


Nuclear Export Dynamics Of Thyroid Hormone Receptors, Kelly Sue Subramanian Jan 2012

Nuclear Export Dynamics Of Thyroid Hormone Receptors, Kelly Sue Subramanian

Dissertations, Theses, and Masters Projects

No abstract provided.


Hydrogen/Deuterium Exchange Studies Of Protein And Non-Protein Amino Acids Using Electrospray Ionization Mass Spectrometry, Justine Victoria Arrington Jan 2012

Hydrogen/Deuterium Exchange Studies Of Protein And Non-Protein Amino Acids Using Electrospray Ionization Mass Spectrometry, Justine Victoria Arrington

Dissertations, Theses, and Masters Projects

No abstract provided.