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Full-Text Articles in Life Sciences

Does Plant Diversity Control Animal Diversity?: An Experimental Approach, John Daniel Parker Jan 1998

Does Plant Diversity Control Animal Diversity?: An Experimental Approach, John Daniel Parker

Dissertations, Theses, and Masters Projects

No abstract provided.


Biogeography Of Amphi-Atlantic And Amphi-American Fishes: The Scomberomorus Regalis (Scombridae), Strongylura Marina (Belonidae) And Hyporhamphus Unifasciatus (Hemiramphidae) Species Groups, Heidi M. Banford Jan 1998

Biogeography Of Amphi-Atlantic And Amphi-American Fishes: The Scomberomorus Regalis (Scombridae), Strongylura Marina (Belonidae) And Hyporhamphus Unifasciatus (Hemiramphidae) Species Groups, Heidi M. Banford

Dissertations, Theses, and Masters Projects

Phylogenetic and historical biogeographic hypotheses were explored for three groups of teleost fishes that are hypothesized to share a common biogeographic track. Distributed across the eastern Pacific/eastern Atlantic (EP/EA) biogeographic track of Rosen (1975) are the Scomberomorus regalis (Scombridae), Strongylura marina (Belonidae) and Hyporhamphus unifasciatus (Hemiramphidae) species groups comprised of one eastern Atlantic; three, three and four western Atlantic; and two, two and four eastern Pacific species, respectively, for each group. In addition, two species in the Strongylura marina and Hyporhamphus unifasciatus groups, have invaded freshwater drainages of Central and South America. Each of the three species groups ...


The Phylogeny Of Coleoid Cephalopods Inferred From Molecular Evolutionary Analyses Of The Cytochrome C Oxidase I, Muscle Actin, And Cytoplasmic Actin Genes, David Bruno Carlini Jan 1998

The Phylogeny Of Coleoid Cephalopods Inferred From Molecular Evolutionary Analyses Of The Cytochrome C Oxidase I, Muscle Actin, And Cytoplasmic Actin Genes, David Bruno Carlini

Dissertations, Theses, and Masters Projects

Although the fossil record of early cephalopods is rich and demonstrates the dominance of the group in Paleozoic times, the mainly soft-bodied coleoids (Cephalopoda: Coleoidea) are poorly represented. Therefore, little is known of the evolutionary history of coleoids through paleontology and current classifications of the subclass are based primarily on the morphology of extant representatives. A molecular phylogenetic analysis of the Coleoidea was therefore warranted. Phylogenetic relationships within the Coleoidea were constructed using molecular sequence data from one mitochondrial and two nuclear genes: cytochrome c oxidase I (COI) and two unlinked actin genes (Actin I and Actin II, respectively). A ...


Habitat Use, Secondary Production, And Trophic Export By Salt Marsh Nekton In Shallow Waters, Giancarlo Cicchetti Jan 1998

Habitat Use, Secondary Production, And Trophic Export By Salt Marsh Nekton In Shallow Waters, Giancarlo Cicchetti

Dissertations, Theses, and Masters Projects

I used 1.75 m&\sp2& drop rings and throw rings to sample communities of nekton at high and low tides in contiguous salt marshes, unvegetated flats, and seagrass beds (Ruppia maritima) of lower Chesapeake Bay. Thirty-two species of nekton were captured between June and October 1995, with a mean overall abundance of 28.6 inds m&\sp{lcub}-2{rcub}& and a mean biomass of 3.8 g m&\sp{lcub}-2{rcub}& (dry weight, dw). Blue crabs, Callinectes sapidus, were the biomass dominants and used seagrass and marsh edge habitats extensively from recruitment to maturity. Palaemonetes shrimp were the most abundant nekton; patterns of allopatry and apparent sympatry were found among the three species present. Menidia menidia used the marsh surface at night. Behavioral patterns for marsh residents Fundulus heteroclitus, F. majalis, Lucania parva, Gobiosoma bosc, and P. intermedius differed from patterns reported elsewhere. This suggests behavioral flexibility in habitat use between regions. Seagrass and marsh edges supported a large biomass of nekton. Secondary production on the marsh surface was estimated at 7.4-8.0 gdw m&\rm\sp{lcub}-2{rcub}150\ d\sp{lcub}-1{rcub}& (28.4-30.7 gww m&\rm\sp{lcub}-2{rcub}150\ d\sp{lcub}-1{rcub}&) between June and October 1995 (150 days). Gut contents of predators were examined, and a mathematical model was constructed to estimate consumption and export by nekton. Predation on invertebrates was highest in marsh edge areas, at 44.2 gdw m&\rm\sp{lcub}-2{rcub}150\ d\sp{lcub}-1{rcub}& removed; predation at the edge by transients (export) was 28.0 gdw m&\rm\sp{lcub}-2{rcub} 150\ d\sp{lcub}-1{rcub}.& The value of marsh edge was clearly linked to both vegetated and unvegetated components as refuge and feeding. Predation in the entire marsh was approximately 13 gdw m&\rm\sp{lcub}-2{rcub} 150\ d\sp{lcub}-1{rcub},& and transient export was 5.6 gdw m&\rm\sp{lcub}-2{rcub} 150\ d\sp{lcub}-1{rcub}.& Most export from marsh interior habitats was via blue crab predation on Uca and Sesarma. Predation in unvegetated areas was 13.3-17.0 gdw m&\rm\sp{lcub}-2{rcub} 150\ d\sp{lcub}-1{rcub};& export was 8.0-11.7 gdw m&\rm ...


Comparative Evolution Of Molecular Markers: An Analysis Of Genetic Variation Within The Blue Marlin (Makaira Nigricans), Vincent Patrick Buonaccorsi Jan 1998

Comparative Evolution Of Molecular Markers: An Analysis Of Genetic Variation Within The Blue Marlin (Makaira Nigricans), Vincent Patrick Buonaccorsi

Dissertations, Theses, and Masters Projects

Blue marlin diversity was assessed at mtDNA, scnDNA, microsatellite DNA, and allozyme molecular markers. Hierarchical analysis of molecular variance (AMOVA) revealed that most genetic variation was maintained within populations, with a non-significant fraction attributable to variation among temporal replicates and between locations within oceans. In contrast, inter-ocean divergence was highly significant for a majority of loci within each marker class. Previous studies of mitochondrial DNA (mtDNA; n = 104) genetic variation within the blue marlin revealed two distinct clades of haplotypes, one of which was present only in the Atlantic (the 'Atlantic clade'), at a frequency of 40% &(F\sb{lcub ...


The Parasite Fauna Of The Wreckfish, Polyprion Americanus, In The North Atlantic Ocean: Application To Host Biology And Stock Identification, Colleen Jill Fennessy Jan 1998

The Parasite Fauna Of The Wreckfish, Polyprion Americanus, In The North Atlantic Ocean: Application To Host Biology And Stock Identification, Colleen Jill Fennessy

Dissertations, Theses, and Masters Projects

No abstract provided.


Physical Parameters Affecting Incubating Temperatures In Loggerhead Sea Turtles, Caretta Caretta, In Virginia, William Mason Jones Jan 1998

Physical Parameters Affecting Incubating Temperatures In Loggerhead Sea Turtles, Caretta Caretta, In Virginia, William Mason Jones

Dissertations, Theses, and Masters Projects

Detailed physical profile of eight transplanted loggerhead sea turtle, Caretta caretta, nests were obtained from Virginia and northeastern North Carolina and reburied in Back Bay National Wildlife Refuge (BBNWR), Virginia Beach, Virginia during the summers of 1987, '88, and '89 to determine if the physical location of the egg within the nest had an affect on sex determination. Transplanted nests were reburied in sandy substrate at a depth of 15-60 em on south facing dunes, and a Campbell Scientific data-logger logged synchronously environmental data. The following data were collected: temperatures at various locations within a nest, net absorbed radiation, ambient ...


Tidal Freshwater And Oligohaline Benthos: Evaluating The Development Of A Benthic Index Of Biological Integrity For Chesapeake Bay, Robyn C. Draheim Jan 1998

Tidal Freshwater And Oligohaline Benthos: Evaluating The Development Of A Benthic Index Of Biological Integrity For Chesapeake Bay, Robyn C. Draheim

Dissertations, Theses, and Masters Projects

No abstract provided.


Development And Analysis Of A Nutrient Trading Program For The James River Watershed, Jennifer M. Reid Jan 1998

Development And Analysis Of A Nutrient Trading Program For The James River Watershed, Jennifer M. Reid

Dissertations, Theses, and Masters Projects

No abstract provided.


Tagging And Habitat Utilization Of Juvenile Summer Flounder, Paralichthys Dentatus, Richard Thomas Kraus Jan 1998

Tagging And Habitat Utilization Of Juvenile Summer Flounder, Paralichthys Dentatus, Richard Thomas Kraus

Dissertations, Theses, and Masters Projects

No abstract provided.


Natural Variation In The Vertical Distribution Of Macrobenthic Invertebrates Within Sandy-Mud Habitats, Amanda Maxemchuk-Daly Jan 1998

Natural Variation In The Vertical Distribution Of Macrobenthic Invertebrates Within Sandy-Mud Habitats, Amanda Maxemchuk-Daly

Dissertations, Theses, and Masters Projects

No abstract provided.


Early Secondary Succession In The Bottomland Hardwood Forests Of Southeastern Virginia, David Randolph Spencer Jan 1998

Early Secondary Succession In The Bottomland Hardwood Forests Of Southeastern Virginia, David Randolph Spencer

Dissertations, Theses, and Masters Projects

No abstract provided.


The Effects Of Increased Inundation And Wrack Deposition On Photosynthesis And Respiration In A Virginia Salt Marsh, W. David Miller Jan 1998

The Effects Of Increased Inundation And Wrack Deposition On Photosynthesis And Respiration In A Virginia Salt Marsh, W. David Miller

Dissertations, Theses, and Masters Projects

No abstract provided.


Ethanol Preference In Peromyscus: An Association With Compromised Ethanol Metabolism, James Scott Lowman Jan 1998

Ethanol Preference In Peromyscus: An Association With Compromised Ethanol Metabolism, James Scott Lowman

Dissertations, Theses, and Masters Projects

No abstract provided.


Cell-Cell Interactions In The Development Of The Vascular System Of Xenopus, Krista Marie Stimson Jan 1998

Cell-Cell Interactions In The Development Of The Vascular System Of Xenopus, Krista Marie Stimson

Dissertations, Theses, and Masters Projects

No abstract provided.


Caribbean Spiny Lobster And Their Molluscan Prey: Are Top-Down Forces Key In Structuring Prey Assemblages In A Florida Bay Seagrass System, Martha Nizinski Jan 1998

Caribbean Spiny Lobster And Their Molluscan Prey: Are Top-Down Forces Key In Structuring Prey Assemblages In A Florida Bay Seagrass System, Martha Nizinski

Dissertations, Theses, and Masters Projects

Relative importance of predator-prey dynamics and several environmental variables in structuring gastropod and bivalve diversity and distribution was investigated in the subtropical seagrass and macroalgal community of Florida Bay, a highly productive system and primary nursery and foraging ground for finfish and invertebrate predators, including the numerically dominant Caribbean spiny lobster, Panulirus argus. The molluscan assemblage, a primary food source for P. argus in particular, is speciose (75 gastropod and 25 bivalve species) and a significant component of epifaunal and infaunal invertebrate assemblages within Florida Bay. Two experimental areas, located within separate basins and each comprised of two experimental sites ...


Ecosystem Analysis Of Water Column Processes In The York River Estuary, Virginia: Historical Records, Field Studies And Modeling Analysis, Yongsik Sin Jan 1998

Ecosystem Analysis Of Water Column Processes In The York River Estuary, Virginia: Historical Records, Field Studies And Modeling Analysis, Yongsik Sin

Dissertations, Theses, and Masters Projects

Analyses of EPA long-term datasets (1985--1994) combined with field studies and ecosystem model development were used to investigate phytoplankton and nutrient dynamics in the York River estuary. Analysis of the EPA dataset showed that algal blooms occurred during winter-spring followed by smaller summer blooms. Peak phytoplankton biomass during the winter-spring blooms occurred in the mid reach of the mesohaline zone whereas during the summer bloom it occurred in the tidal fresh-mesolialine transition zone. River discharge appears to be the major factor controlling the location and timing of the winter-spring blooms and the relative degree of potential nitrogen (N) and phosphorus ...


Interactive Effects Of Cadmium And Benzo(A)Pyrene In Mummichog (Fundulus Heteroclitus), Peter Van Den Hurk Jan 1998

Interactive Effects Of Cadmium And Benzo(A)Pyrene In Mummichog (Fundulus Heteroclitus), Peter Van Den Hurk

Dissertations, Theses, and Masters Projects

When animals are exposed to mixtures of environmental pollutants, it is generally assumed that the toxic effects of the individual components are additive. However, examples of synergistic and antagonistic effects have been described. to study the mechanisms of interaction between a metal and a polycyclic aromatic hydrocarbon, mummichog (Fundulus heteroclitus) were injected with combinations of cadmium (Cd) and benzo (a) pyrene (BP). Measured effect parameters were: mortality, BP-metabolite production in isolated hepatocytes and microsomes, hepatic induction of CYP1A (the BP metabolizing enzyme) and metallothionein (the Cd binding protein), and biliary excretion of BP-metabolites. The mortality data demonstrated that both synergistic ...


Variation Between Sparrows In The Ability To Extract Buried Seed, David Michael Whalen Jan 1998

Variation Between Sparrows In The Ability To Extract Buried Seed, David Michael Whalen

Dissertations, Theses, and Masters Projects

No abstract provided.


Determination Of Trace Levels Of Lead In Whole Blood By Graphite Furnace Atomic Absorption Spectroscopy, Leslie A. Sombers Jan 1998

Determination Of Trace Levels Of Lead In Whole Blood By Graphite Furnace Atomic Absorption Spectroscopy, Leslie A. Sombers

Dissertations, Theses, and Masters Projects

No abstract provided.


Phenotypic Clines In The Intertidal Snail Littorina Obtusata: The Role Of Water Temperature And Predator Effluent As Inducers Of Phenotypic Plasticity And Associated Trade-Offs In Shell Form, Geoffrey Clayton Trussell Jan 1998

Phenotypic Clines In The Intertidal Snail Littorina Obtusata: The Role Of Water Temperature And Predator Effluent As Inducers Of Phenotypic Plasticity And Associated Trade-Offs In Shell Form, Geoffrey Clayton Trussell

Dissertations, Theses, and Masters Projects

I examined variability in the shell form of 25 Littorina obtusata populations from Massachusetts to northern Maine. I chose this scale because the history of one of L. obtusata's principal predators, the crab Carcinus maenas, has changed dramatically in the past 100 years. Before 1900, Carcinus did not occur north of Cape Cod, Massachusetts, but by 1950 it had reached Canadian border. Moreover, in summer water temperatures during average 6-8&\sp\circ&C colder at northern locations. Shell thickness and mass increased and body mass decreased with increasing latitude. to test whether these patterns reflect plasticity in response to ...


Oyster Reef Broodstock Enhancement In The Great Wicomico River, Virginia, Melissa J. Southworth Jan 1998

Oyster Reef Broodstock Enhancement In The Great Wicomico River, Virginia, Melissa J. Southworth

Dissertations, Theses, and Masters Projects

No abstract provided.


The Agroecologies Of A Southern Community: The Tye River Valley Of Virginia, 1730-1860, Lynn A. Nelson Jan 1998

The Agroecologies Of A Southern Community: The Tye River Valley Of Virginia, 1730-1860, Lynn A. Nelson

Dissertations, Theses, and Masters Projects

The farmers of piedmont Virginia's Tye River Valley adapted agriculture to a commercial frontier during the eighteenth century. This 'frontier agroecosystem' optimized labor returns by exploiting the stored fertility of mature ecosystems at the expense of conservation, but proved vulnerable to population growth and soil exhaustion. Out-migration increased after the Revolution, and economic growth was stymied by limited capital and consumer formation. The frontier agroecosystem could not provide the reliable commercial returns needed to promote development or stable neighborhoods.;During the early 1800s, prominent planters demanded that Virginia farming be intensified---that land productivity be maximized, rather than labor productivity ...