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Articles 1 - 25 of 25
Full-Text Articles in Life Sciences
Reproductive Success Of Black Skimmers On An Artificial Island: Effects Of Hatching Date And Feeding Rate, Christopher Alan Gordon
Reproductive Success Of Black Skimmers On An Artificial Island: Effects Of Hatching Date And Feeding Rate, Christopher Alan Gordon
Dissertations, Theses, and Masters Projects
No abstract provided.
Nest Site Selection Of The Brown-Headed Nuthatch In Virginia, Valerie A. Weiss
Nest Site Selection Of The Brown-Headed Nuthatch In Virginia, Valerie A. Weiss
Dissertations, Theses, and Masters Projects
No abstract provided.
Environmental Stress In Hard Coral: Evaluating Lipid As An Indicator Of Sublethal Stress On Short Time Scales, David Harold Niebuhr
Environmental Stress In Hard Coral: Evaluating Lipid As An Indicator Of Sublethal Stress On Short Time Scales, David Harold Niebuhr
Dissertations, Theses, and Masters Projects
Lipid quality was evaluated in Montastrea spp. under sediment- and heat-stressed conditions to evaluate lipid ratio as an indicator of sub-lethal stress on short time scales. The ratio of storage lipid (wax ester + triacylglyceride) to structural lipid (sterol esters + phospholipid) decreased significantly (0.25 to 0.14, p < 0.01) after experimental sedimentation. FAME analysis of colonies exposed to experimental sedimentation showed a reduction of the algal, 18:3(n-6) and 18:4(n-3), polyunsaturated fatty acid (PUFA) in the polar lipid fraction. This loss of PUFA suggests a loss of algal membrane in sediment-stressed colonies. Lipid quality was similarly measured in M. faveolata over a 10-day period. Mean (n = 20) ratio of storage to structural lipid in M. faveolata dropped from 2.43 to a level of 0.98 immediately following a natural sedimentation event before recovering to levels of 1.4 and 2.9 on post-storm days 2 and 4, respectively. Colonies of M. annularis subject to heat-stress (35??C) exhibited no significant change in storage lipid ratio, while levels of Free Fatty Acids increased significantly from 0.012 (n = 22) to 0.156 mg lipid/g dry tissue (n = 22)(p < 0.05). FAME analysis of tissue lipids extracted from the heat-stressed colonies showed changes in the polar fraction, with significant decreases in the 18:3(n-6), 18:3(n-3), 18:4(n-3), 20:4(n-6) and 20:5(n-3) (p < 0.05) PUFA and subsequent significant increases in the saturated fatty acids, 16:0 and 18:0 (p < 0.05). These changes in lipid quantity and quality indicate possible oxidation and preferential digestion of zooxanthellar membranes. Stress experiments were repeated in M. annularis using VacutainerRTM blood collection tubes to collect micro-tissue samples without destroying skeleton of the sample colonies. A significant decrease in storage: structural lipid ratio after sedimentation was also detected using the micro-tissue technique. This study indicates that the relative abundance of lipid subclass components can indicate sub-lethal environmental stress, on short time scales, in M. annularis and M. faveolata. Furthermore, micro-tissue collection techniques permit repeated monitoring coral colonies to assess the manifestation of stress from first detection of impact at the cellular level to changes in community to changes in community structure detectable over longer time scales.
Bacterial Dynamics And Community Structure In The York River Estuary, Gary Edward Schultz Jr
Bacterial Dynamics And Community Structure In The York River Estuary, Gary Edward Schultz Jr
Dissertations, Theses, and Masters Projects
Bacterial community dynamics were investigated over seasonal and basin scales within the York River, VA, estuary. Various parameters characterizing bacterioplankton dynamics were measured weekly at a single station (March 1996 through May 1997) and monthly at six stations (June 1996 through May 1997) spanning the entire salinity gradient (0 - ca. 20 psu over 60 km). Bacterial abundance and production were found to be high throughout the estuary. Bacterial abundance ranged from 4.4 x 108 to 1.3 x 1010 cells-liter-1Incorporation of 3H-thymidine ranged from 10 to 863 pmol-liter-1-hr-1 while 3H-leucine incorporation rates ranged from 25 to 1963 pmol-liter -1-hr-1. Clear …
Morphological, Electrophysiological And Behavioral Investigation Of Visual Acuity Of The Juvenile Loggerhead Sea Turtle (Caretta Caretta), Soraya M. Bartol
Morphological, Electrophysiological And Behavioral Investigation Of Visual Acuity Of The Juvenile Loggerhead Sea Turtle (Caretta Caretta), Soraya M. Bartol
Dissertations, Theses, and Masters Projects
A majority of the research on sea turtle vision focuses on the turtle's ability to perceive shapes, colors and brightness cues on land. However, aerial vision is a minor component of the visual ability of sea turtles, potentially used only when surfacing to breathe, while basking, and during female reproductive activities. For my doctoral dissertation, I examined the aquatic visual acuity of juvenile loggerhead sea turtles (Caretta caretta) by investigating the morphology of the eye, the electrophysiology of response to stimuli, and the behavior to specific stimuli. For the morphological experiments, eyes were obtained from loggerheads, euthanized due to injury, …
32p-Postlabeling Analysis Of Aromatic Dna Adducts In Hemopoietic Tissues And Blood Of The Mummichog Fundulus Heteroclitus, Wendy L. Rose
32p-Postlabeling Analysis Of Aromatic Dna Adducts In Hemopoietic Tissues And Blood Of The Mummichog Fundulus Heteroclitus, Wendy L. Rose
Dissertations, Theses, and Masters Projects
No abstract provided.
Functional And Molecular Analysis Of Antibody Affinity Maturation In Rainbow Trout (Oncorhynchus Mykiss), Haili Zhang
Functional And Molecular Analysis Of Antibody Affinity Maturation In Rainbow Trout (Oncorhynchus Mykiss), Haili Zhang
Dissertations, Theses, and Masters Projects
No abstract provided.
Aspects Of The Biology Of Sea Turtles In The Mid-Atlantic Bight, William C. Coles
Aspects Of The Biology Of Sea Turtles In The Mid-Atlantic Bight, William C. Coles
Dissertations, Theses, and Masters Projects
I present here an investigation of several aspects of the biology of sea turtles in the mid-Atlantic Bight. During 19 years of data collection, included in this study, strandings have increased for all species of sea turtles in Virginia. Most sea turtle strandings occurred during the spring when juvenile turtles migrate into the Bay (Kemp's ridleys had a second significant stranding peak, during fall migration) along the Southern Bay and Virginia Beach Oceanfront. Sea turtles utilize the Chesapeake Bay as a feeding area when the water temperature approaches 20??C, and they leave after the water temperature drops below 20??C. Although …
Relationships Between Experience, Credentials, Moral Development, Conceptual Level, And Self-Efficacy Of School Counselors, Susan Emilie Halverson
Relationships Between Experience, Credentials, Moral Development, Conceptual Level, And Self-Efficacy Of School Counselors, Susan Emilie Halverson
Dissertations, Theses, and Masters Projects
No abstract provided.
Diet Composition And Feeding Habits Of Large Striped Bass, Morone Saxatilis, In Chesapeake Bay, John F. Walter
Diet Composition And Feeding Habits Of Large Striped Bass, Morone Saxatilis, In Chesapeake Bay, John F. Walter
Dissertations, Theses, and Masters Projects
No abstract provided.
Spatial And Temporal Distributions Of Organic Matter And Polycyclic Aromatic Hydrocarbons (Pahs) In Surface Waters Of The York River, Va Estuary, Rebecca E. Countway
Spatial And Temporal Distributions Of Organic Matter And Polycyclic Aromatic Hydrocarbons (Pahs) In Surface Waters Of The York River, Va Estuary, Rebecca E. Countway
Dissertations, Theses, and Masters Projects
No abstract provided.
Carbon Production And Growth Physiology Of Heterotrophic Bacteria In A Subtropical Coral Reef Ecosystem, Peter Dylan Countway
Carbon Production And Growth Physiology Of Heterotrophic Bacteria In A Subtropical Coral Reef Ecosystem, Peter Dylan Countway
Dissertations, Theses, and Masters Projects
No abstract provided.
Indo-Pacific Population Structure Of The Black Marlin, Makaira Indica, Inferred From Molecular Markers, Brett Falterman
Indo-Pacific Population Structure Of The Black Marlin, Makaira Indica, Inferred From Molecular Markers, Brett Falterman
Dissertations, Theses, and Masters Projects
No abstract provided.
Limitation Of Bacterial Growth By Dissolved Organic Matter And Iron In The Southern Ocean, Matthew J. Church
Limitation Of Bacterial Growth By Dissolved Organic Matter And Iron In The Southern Ocean, Matthew J. Church
Dissertations, Theses, and Masters Projects
No abstract provided.
A Comparison Of Size Selectivity And Relative Efficiency Of Sea Scallop Trawls And Dredges, David B. Rudders
A Comparison Of Size Selectivity And Relative Efficiency Of Sea Scallop Trawls And Dredges, David B. Rudders
Dissertations, Theses, and Masters Projects
No abstract provided.
Timing Of Spring Migration In White-Throated Sparrows, Karen M. Johnson
Timing Of Spring Migration In White-Throated Sparrows, Karen M. Johnson
Dissertations, Theses, and Masters Projects
No abstract provided.
Habitat Fragmentation In Transplanted Eelgrass (Zostera Marina) Beds: Effects On Decapods And Fish, Alfonso Vollmer Lombana
Habitat Fragmentation In Transplanted Eelgrass (Zostera Marina) Beds: Effects On Decapods And Fish, Alfonso Vollmer Lombana
Dissertations, Theses, and Masters Projects
No abstract provided.
The Effect Of Seagrass Habitat Fragmentation On Juvenile Blue Crab Survival, Kevin Hovel
The Effect Of Seagrass Habitat Fragmentation On Juvenile Blue Crab Survival, Kevin Hovel
Dissertations, Theses, and Masters Projects
Habitat fragmentation leads to small, isolated habitat patches in which ecological processes may differ substantially from those in larger, continuous habitats. Seagrass is a structurally complex but fragmented subtidal habitat that serves as a refuge from predation for juveniles of the blue crab, Callinectes sapidus Rathbun. I compared the effects of eelgrass ( Zostera marina L.) patch size and shoot density on juvenile blue crab survival both before (June) and after (September) shoot defoliation and cownose ray disturbance changed eelgrass habitat, and used artificial seagrass to determine the influence of eelgrass patch size on juvenile blue crab survival in the …
Sensory Development In Settlement-Stage Larvae Of Caribbean Labrids And Scarids: A Comparative Study With Implications For Ecomorphology And Life History Strategies, Monica R. Lara
Dissertations, Theses, and Masters Projects
The sensory capabilities of settlement-stage fishes are unknown but this information is necessary to studies of larval settlement and recruitment. The morphology of the cephalic lateral line, eye and external olfactory organ of thirteen species of settlement-stage Caribbean labroids was described. Scanning electron images of the cephalic lateral line neuromasts, lateral line canals and olfactory epithelia and histological studies of the retinae and morphological measurements of visual acuity were used to assess the level of sensory development attained at settlement. The sensory capabilities of settlement-stage fishes are discussed in relation to the possible cues settlement-stage fishes may be using to …
Molecular Phylogeny Of Lake Baikal Amphipods, Kenneth S. Macdonald
Molecular Phylogeny Of Lake Baikal Amphipods, Kenneth S. Macdonald
Dissertations, Theses, and Masters Projects
No abstract provided.
Distribution, Swimming Physiology, And Swimming Mechanics Of Brief Squid Lolliguncula Brevis, Ian K. Bartol
Distribution, Swimming Physiology, And Swimming Mechanics Of Brief Squid Lolliguncula Brevis, Ian K. Bartol
Dissertations, Theses, and Masters Projects
Squids are thought to have physiological and locomotive deficiencies that put them at a competitive disadvantage to fishes and exclude them from inshore, highly variable environments that are rich in nektonic fauna. However, brief squid Lolliguncula brevis may be a notable exception. Trawl surveys revealed that L. brevis, particularly juveniles <6 cm dorsal mantle length (DML), are abundant in the Chesapeake Bay, especially when salinity and water temperature are high, and tolerate a wide range of physical conditions relative to other cephalopods. L. brevis is also different from other cephalopods examined previously because its pattern of oxygen consumption as a function of velocity was found to be parabolic and thus similar to aerial flight, and its swimming costs were competitive with ecologically equivalent fishes. Power-speed curves derived from video footage of swimming squid and hydrodynamic force calculations also were parabolic in shape, with high costs both at low and high speeds because of power requirements for lift generation and overcoming drag, respectively. L. brevis employed various behaviors to increase swimming efficiency and compensate for negative buoyancy, such as swimming in various orientations (e.g., arms-first and tail-first), altering angles of attack of the mantle, arms, and funnel, and using fin activity. Fin motion, which could not be characterized exclusively as drag- or lift-based propulsion, was used over 50--95% of the sustained speed range and provided as much as 78% of the vertical and 55% of the horizontal thrust. Small squid (<3.0 cm DML) used different swimming strategies than larger squid possibly to maximize the benefits of toroidal induction, and aerobic efficiency curves indicated that squid 3--5 cm. DML are most efficient. Brief squid also may take advantage of unsteady phenomena, such as attached vortices, for added lift and thrust. Furthermore, an electromyographic study revealed that L. brevis uses different circular muscle layers for various speeds and like fish has muscular "gears", suggesting that there is specialization and efficient use of locomotive muscle in some cephalopods. Therefore, the presumption that squids are inescapably constrained by a second-rate propulsive system and physiological deficiencies is not applicable to L. brevis.
Characterization Of The Defensive Efficacy Of The Sternal Secretion Of Eurycotis Floridana (Walker) (Dictyoptera: Blattidae), Matthew William Turnbull
Characterization Of The Defensive Efficacy Of The Sternal Secretion Of Eurycotis Floridana (Walker) (Dictyoptera: Blattidae), Matthew William Turnbull
Dissertations, Theses, and Masters Projects
No abstract provided.
Phylogenetic Implications Of Sporangial Ultrastructure In The Subfamily Lithophylloideae (Corallinales, Rhodophyta), Mark T. Bedell
Phylogenetic Implications Of Sporangial Ultrastructure In The Subfamily Lithophylloideae (Corallinales, Rhodophyta), Mark T. Bedell
Dissertations, Theses, and Masters Projects
No abstract provided.
Circadian Rhythms And Melatonin Receptors As Sources Of Individual Variation In Reproductive Photoresponsiveness, Sean Bradford Majoy
Circadian Rhythms And Melatonin Receptors As Sources Of Individual Variation In Reproductive Photoresponsiveness, Sean Bradford Majoy
Dissertations, Theses, and Masters Projects
No abstract provided.
Frequencies Of Suspension-Feeding Actions Vary With Prey Type In Oreochromis Niloticus (Pisces: Cichlidae), K. Lara Ackermann
Frequencies Of Suspension-Feeding Actions Vary With Prey Type In Oreochromis Niloticus (Pisces: Cichlidae), K. Lara Ackermann
Dissertations, Theses, and Masters Projects
No abstract provided.