Ecology and Evolutionary Biology Commons^™

Effect Of The Herbivorous Channel Clinging Crab (Mithrax Spinosissimus) On Patch Reef Algal Communities In The Florida Keys, Florida (Usa), Angela M. Mojica Osorio

Biological Sciences Theses & Dissertations

Coral reefs worldwide are undergoing dramatic habitat modification from coral to macroalgal dominance due to water pollution, coral diseases, global. warming, and the loss of herbivores. This phase-shift bas been particularly severe on Caribbean reefs due in large measure to the decline of piscine and echinoderm grazers, whose presence appears crucial for stemming the decline of coral reefs and enhancing their resilience. Virtually unknown, however, is the role of other macrograzers in coral reef ecosystems. This is the first study to examine the feeding ecology and grazer effect of the herbivorous West Indian spider crab (Mithrax spinosissimus) on inshore patch …

Factors Affecting Adult Foraging And Chick Growth Of Adélie Penguins (Pygoscelis Adeliae) Off The Western Antarctic Peninsula: A Modeling Study, Erik W. Chapman

OES Theses and Dissertations

Coupled individual-based models that simulate Adélie penguin ( Pygoscelis adeliae) chick growth and adult foraging behavior during the chick growth period were developed and used to explore factors that influence chick fledging mass and adult foraging energetics off the western Antarctic Peninsula (WAP). Adélie penguin colonies in this region are undergoing changes in population size that have been correlated with climate-driven alteration of the marine and terrestrial environment. Simulations were selected to highlight possible mechanistic linkages between climate variability and chick growth and adult foraging processes. These processes were the focus of this study because chicks that fledge at …

Optics And Remote Sensing Of Bahamian Carbonate Sediment Whitings And Potential Relationship To Wind-Driven Langmuir Circulation, H. M. Dierssen, Richard C. Zimmerman, David J. Burdige

OES Faculty Publications

Regions of milky white seas or "whitings" periodically occur to the west of Andros Island along the Great Bahama Bank where the bottom sediment consists of fine-grained aragonite mud. We present measurements of inherent optical properties within a sediment whiting patch and discuss the potential for monitoring the frequency, extent, and quantity of suspended matter from ocean colour satellite imagery. Sea spectral reflectance measured in situ and remotely from space revealed highly reflective waters elevated across the visible spectrum (i.e., "whitened") with a peak at 490 nm. Particulate backscattering was an order of magnitude higher than that measured at other …

Patterns Of Spiny Lobster (Panulirus Argus) Postlarval Recruitment In The Carribbean: A Crtr Project, Mark J. Butler Iv, Angela M. Mojica, Eloy Sosa-Cordero, Marines Millet, Paul Sanchez-Navarro, Miguel A. Maldonado, Juan Posada, Bladimir Rodriguez, Carlos M. Rivas, Adrian Oviedo, Marcio Arrone, Martha Prada, Nick Bach, Nilda Jimenez, Maria Del Carmen Garcia-Rivas, Kirah Forman, Donald C. Behringer Jr., Thomas Matthews, Claire Paris, Robert Cowen

Biological Sciences Faculty Publications

As part of the Coral Reef Targeted Research (CRTR) Program, a partnership between the Global Environment Facility and the World Bank, our research team examined the recruitment patterns of Caribbean spiny lobster (Panulirus argus) postlarvae among regions in the Caribbean, with a particular focus on Mesoamerica. Our goal was to collect comparable information on postlarval supply among regions and to provide data to test predictions of connectivity generated from a coupled biophysical oceanographic model of lobster larval dispersal. Here we present the results of the postlarval recruitment monitoring program. We monitored the catch of postlarvae on Witham-style collectors …

Enso And Variability Of The Antarctic Peninsula Pelagic Marine Ecosystem, Valerie J. Loeb, Eileen E. Hofmann, John M. Klinck, Osmund Holm-Hansen, Warren B. White

CCPO Publications

The West Antarctic Peninsula region is an important source of Antarctic krill (Euphausia superba) in the Southern Ocean. From 1980-2004 abundance and concentration of phytoplankton and zooplankton, krill reproductive and recruitment success and seasonal sea ice extent here were significantly correlated with the atmospheric Southern Oscillation Index and exhibited three- to five-year frequencies characteristic of El Nino-Southern Oscillation (ENSO) variability. This linkage was associated with movements of the Southern Antarctic Circumpolar Current Front and Boundary, a changing influence of Antarctic Circumpolar Current and Weddell Sea waters, and eastward versus westward flow and mixing processes that are consistent with forcing by …

Peptide Hydrolysis And The Uptake Of Dipeptides By Phytoplankton, Margaret R. Mulholland, Cindy Lee

OES Faculty Publications

Rates of peptide hydrolysis (using the fluorescent substrate, lucifer yellow anhydride-labeled tetra-alanine) and dipeptide uptake (using dually labeled, ¹⁵N and ¹³C, dialanine) were measured in phytoplankton cultures and in natural populations during algal blooms dominated by one or two taxa. During most sampling events, both peptide hydrolysis and dipeptide uptake were greatest in the size fraction containing the dominant phytoplankter, suggesting that phytoplankton contribute substantially to or may even dominate observed extracellular peptide hydrolysis and dipeptide uptake in the environment. These are the first data suggesting that dipeptides may be taken up directly by phytoplankton and this may …

Ecology And Molecular Phylogenetics Of Hydnora (Hydnoraceae) In Southern Africa, Jay Francis Bolin

Biological Sciences Theses & Dissertations

The Hydnoraceae are a clade of root holoparasitic angiosperms that contain two small genera, Hydnora and Prosopanche. This study, focused on Hydnora, presents novel data regarding the pollination biology, germination ecology, parasite-host nutritional relationships, and the molecular systematics of this group. Experimental addition of the primary pollinator, Dermestes maculatus to Hydnora africana chamber flowers demonstrated beetle imprisonment during the carpellate stage. Changes in the inner surfaces of the androecial chamber allowed beetle escape after pollen release. Most beetles escaped, dusted with viable pollen, three days after pollen release. To investigate germination ecology, aqueous root extracts of host and …

Ecology Of Neotropical Arboreal Snakes And Behavior Of New World Mollusk-Eating Snakes, Julie M. Ray

Biological Sciences Theses & Dissertations

The Neotropics is a biologically diverse region that provides man opportunities for ecological and behavioral studies. I utilized the speciose ophidian fauna of central Panama to explore the general ecology of arboreal snakes, the defensive behaviors of the snake community, and the diet of mollusk-eating snakes. I studied arboreal species to understand interspecilic relationships in several morphometric characters and to examine preferences in habitat. There were significant morphometric differences in relative length of jaw, mass, tail length, and size at midbody. The arboreal realm was partitioned among species by distance to ground, distance to water, and diameter of the perch. …

Current Status And Long-Term Trends In Water Quality And Living Resources In The Virginia Tributaries And Chesapeake Bay Mainstem From 1985 Through 2007, Daniel M. Dauer, Harold G. Marshal, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman

Status and Trends for Virginia Chesapeake Bay

The period prior to the implementation of the Chesapeake Bay Monitoring Program was characterized by a marked decline in the water quality of the Chesapeake Bay. The disappearance of submerged aquatic vegetation in certain regions of the Bay, declines in the abundance of some commercially and recreationally important species, increases in the incidence of low dissolved oxygen events, changes in the Bay's food web, and other ecological problems were related to deteriorating water quality (e.g. USEPA, 1982,1983;Officer et al.,1984; Orth and Moore, 1984). The results of concentrated research efforts in the late 1970s and early 1980s stimulated the establishment of …

Dinoflagellate Cysts Within Sediment Collections From The Southern Chesapeake Bay, And Tidal Regions Of The James, York, And Rappahannock Rivers, Virginia, David W. Seaborn, Harold G. Marshall

Virginia Journal of Science

The upper 2 cm of sediment core samples from 70 stations in the tidal waters of three Virginia rivers and at 23 stations in the lower Chesapeake Bay were sampled for dinoflagellate cysts. The river sediment cysts were dominated by three common bloom producing species (Heterocapsa triquetra, Scrippsiella trochoidea, and Cochlodinium polykrikoides), whereas these were in low concentration on the Chesapeake Bay sediments which contained mainly dinoflagellate cysts of neritic and oceanic taxa. The mean sediment concentrations from stations in the James, York, and Rappahannock rivers were respectively 1174.8, 536.2, and 323.6 cysts g^-1. The mean …

Induction Of Winter Breeding In Small Mammals By 6-Mboa, Robert K. Rose, Roger K. Everton, Gregory E. Glass

Virginia Journal of Science

A plant-derived cyclic carbamate, 6-methoxybenzoxazolinone (6-MBOA), is

known to initiate reproductive activity in Microtus montanus. We studied

overwintering populations of four other rodent species, and observed increased

reproduction in experimental populations of two herbivorous species, Microtus

pennsylvanicus and Sigmodon hispidus, but not in two omnivorous species,

Oryzomys palustris and Mus musculus. These results suggest that low

concentrations of 6-MBOA may trigger seasonal breeding primarily in

herbivorous small mammals.

Spatial Analyses And Repletion Of Gargathy Coastal Lagoon, Loreto Herraiz Gomez

OES Theses and Dissertations

Coastal lagoons and bays vary in shape and size in response to antecedent topography, geologic processes and sea level rise. Variations in shape and environmental conditions of coastal basins are believed to influence the distribution of benthic sub-environments and the exchange of water with the ocean and other adjacent coastal systems. Gargathy Inlet and its coastal lagoon vary spatially from the inlet, where the greatest depths are observed, to the mainland, dominated by shallow intertidal areas, colonized by marsh. Hypsographic and hydro-hypsographic analyses of Gargathy's coastal lagoon were the primary techniques applied to understand the relative distribution of the benthic …

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2007), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

Macrobenthic communities of the Elizabeth River watershed have been quantitatively sampled since summer 1999. This report presents the data from the ninth year of sampling in 2007. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. (2) To conduct trend analyses on long-term data at 14 fixed-point stations to relate temporal trends in the benthic communities to changes in water and/or sediment quality. Trend analyses will be updated annually …

A Phylogeny Of The Snappers (Lutjanidae; Percoidei) Inferred From Cytochrome B Sequence Data, Matthew R. Semcheski

Biological Sciences Theses & Dissertations

The Lutjanidae are economically and ecologically important fishes commonly known as snappers. A morphological study of Lutjanidae concluded that it contained four subfamilies and that together with the family Caesionidae, form the superfamily Lutjanoidea. Although this view was supported elsewhere in the literature, it was later contradicted, treating the caesionids as members of the Lutjanidae. In order to infer a phylogeny of genera within Lutjanidae, the complete cytochrome b gene (1140bp) of 21 lutjanid taxa was sequenced and analyzed along with 19 lutjanid, caesionid, and outgroup sequences obtained from GenBank. Data were analyzed for base composition stationarity and saturation. Phylogenetic …

New Records, Biogeography, And Habitat Protection Needs Of Four Species Of Potamon (Decapoda: Brachyura) In Greece, Eugene G. Maurakis, David V. Grimes

Virginia Journal of Science

Objectives are to determine the occurrence of species of Potamon in eastern Crete and the Aegean Islands (Chios, Naxos, Paros, Mykonos, Tinos and Andros); generate phylogenetic relationships among species to propose a biogeographic hypothesis relative to current distributions of the four species of the freshwater crab genus, Potamon, in Greece; and comment on the need to protect habitat suitable for the survival of species of Potamon in the country. Our collections, made in areas not previously sampled by researchers, indicate the presence of Potamon fluviatile on Tinos, N axos, and Andros, and Potamon potamios from central to eastern Crete; …

Spatial And Trophic Dynamics Of A Macrofaunal Community On A High Energy Intertidal Sandflat, Sharon Ann Tatem

Biological Sciences Theses & Dissertations

Spatial and trophic interactions between macrofaunal species were studied in a high energy intertidal system during spring-summer low tides. Bioturbation by the enteropneust hemichordate, Balanoglossus aurantiacus (Girad), as evidenced by large fecal mounds, was a conspicuous feature on the sandflat Sediment characteristics were compared between ambient (non-fecal) and B. aurantiacus fecal mound types (fresh-oxidized, fresh-reduced, aged-oxidized, and aged-reduced). Fecal material was differentiated by age based on the presence or absence of mucus and the time of fecal deposition. The color of fecal material was used to assign oxidative state. Multiple isotopes (carbon, nitrogen, sulfur) were used to determine the origins …

Influences Of The Loggerhead Sponge (Spheciospongia Vesparium) And The Vase Sponge (Ircinia Campana) On Nearshore Hard-Bottom Community Development In The Florida Keys, Scott Donahue

Biological Sciences Theses & Dissertations

Sponges, octocorals, and stony corals are the dominant sessile fauna within shallow, hard-bottom communities in the Florida Keys, FL (USA). The sponge component of these communities is not well studied and has been cyclically decimated from as early as 1844, most recently in south-central Florida Bay in 1991 and 1992, in apparent association with phytoplankton blooms. The purpose of this research was to examine ways in which sponges may contribute to the maintenance of hard-bottom communities. Specifically, I investigated: 1) the effect of sponges and physical structures on local sea floor scouring and thus the potential for maintenance of hard-bottom; …

Population Ecology Of The Golden Mouse, Robert K. Rose

Biological Sciences Faculty Publications

An understanding of the population dynamics of a species requires knowledge of the major life-history parameters of a population, including age at maturity, distribution of age classes, and lifetime reproductive contribution of the sexes, sex ratio, length of the breeding season, mean litter size, rates of growth and survival, and life span. Because few long-term studies have been conducted with Ochrotomys nuttalli as the focal species of investigation, only fragmentary information is available for many population parameters. As importantly, densities of golden mice often are low, making them difficult to evaluate statistically. Little has been published on age at maturity …

Low-Density Rodent Communities In Eastern Virginia, Robert K. Rose, Jean F. Stankavich

Virginia Journal of Science

Two communities of small mammals were live trapped every other week for 15 months in linear oilfield habitat bordered by forested swampland in eastern Virginia. All nine species of the rodent community were present, mostly in low numbers and often intermittently. All species were characterized by high transiency, with a minority of marked animals becoming resident. Despite high trappability, all but two species in these communities had extremely low densities, suggesting that most species could not sustain populations via in situ reproduction.

Ancient Dna Identification Of Early 20th Century Simian T-Cell Leukemia Virus Type 1, Sebastien Calvignac, Jean-Michel Terme, Shannon M. Hensley, Pierre Jalinot, Alex D. Greenwood, Catherine Hanni

Biological Sciences Faculty Publications

The molecular identification of proviruses from ancient tissues (and particularly from bones) remains a contentious issue. It can be expected that the copy number of proviruses will be low, which magnifies the risk of contamination with retroviruses from exogenous sources. To assess the feasibility of paleoretrovirological studies, we attempted to identify proviruses from early 20th century bones of museum specimens while following a strict ancient DNA methodology. Simian T-cell leukemia virus type 1 sequences were successfully obtained and authenticated from a Chlorocebus pygerythrus specimen. This represents the first clear evidence that it will be possible to use museum specimens to …

Mycobacteriosis-Associated Mortality In Wild Striped Bass (Morone Saxatilis) From Chesapeake Bay, Usa, D. T. Gauthier, R. J. Latour, D. M. Heisey, C. F. Bonzek, J. Gartland, E. J. Burge, W. K. Vogelbein

Biological Sciences Faculty Publications

The striped bass (Morone saxatilis) is an economically and ecologically important finfish species along the Atlantic seaboard of the United States. Recent stock assessments in Chesapeake Bay (USA) indicate that non-fishing mortality in striped bass has increased since 1999, concomitant with very high (>50%) prevalence of visceral and dermal disease caused by Mycobacterium spp. Current fishery assessment models do not differentiate between disease and other components of non-fishing mortality (e. g., senescence, predation); therefore, disease impact on the striped bass population has not been established. Specific measurement of mortality associated with mycobacteriosis in wild striped bass is …

Current Status And Long-Term Trends In Water Quality And Living Resources In The Virginia Tributaries And Chesapeake Bay Mainstem From 1985 Through 2006, Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman

Status and Trends for Virginia Chesapeake Bay

The period prior to the implementation of the Chesapeake Bay Monitoring Program was characterized by a marked decline in the water quality of the Chesapeake Bay. The disappearance of submerged aquatic vegetation in certain regions of the Bay, declines in the abundance of some commercially and recreationally important species, increases in the incidence of low dissolved oxygen events, changes in the Bay's food web, and other ecological problems have been related to the deteriorating water quality (e.g. USEPA, 1982,1983;Officer et al.,1984; Orth and Moore, 1984). The results of concentrated research efforts in the late 1970s and early 1980s stimulated the …

Oviposition Behavior Partitions Aquatic Landscapes Along Predation And Nutrient Gradients, C. A. Binckley, W. J. Resetarits Jr.

Biological Sciences Faculty Publications

That individuals attempt to minimize the ratio of mortality risk/growth rate (μ/g) when foraging within individual habitat patches is well established. Do species partition among spatially discrete communities embedded in complex landscapes in a similar manner? We investigated how 3 ovipositing species (2 Hyla treefrogs and a hydrophilid beetle, Tropisternus lateralis) responded to simultaneous gradients of nutrients and predation risk. Species partitioned our experimental metacommunity primarily by reducing oviposition with fish. Tropisternus positively responded to increased nutrients, but the effect decreased with increasing risk, as predicted by μ/g theory. Use of fish habitats by Tropisternus was unrelated to breeding …

Interactions Between Changing Pco2, N2 Fixation, And Fe Limitation In The Marine Unicellular Cyanobacterium Crocosphaera, Fei-Xue Fu, Margaret R. Mulholland, Nathan S. Garcia, Aaron Beck, Mark E. Warner, Sergio A. Sañudo, David A. Hutchins

OES Faculty Publications

We examined the physiological responses of steady-state iron (Fe)-replete and Fe-limited cultures of the biogeochemically critical marine unicellular diazotrophic cyanobacterium Crocosphaera at glacial (19 Pa; 190 ppm), current (39 Pa; 380 ppm), and projected year 2100 (76 Pa; 750 ppm) CO₂ levels. Rates of N₂ and CO₂ fixation and growth increased in step with increasing partial pressure of CO₂ (pCO₂), but only under Fe- replete conditions. N₂) and carbon fixation rates at 75 Pa CO₂ were 1.4-1.8-fold and 1.2-2.0-fold higher, respectively, relative to those at present day and glacial pCO_{2 …}

Food Limitation In Larval Fish: Ontogenetic Variation In Feeding Scope And Its Potential Effect On Survival, Alexander B. Bochdansky, Peter Grønkjær, Pierre Pepin, William C. Leggett

OES Faculty Publications

We used the radiated shanny Ulvaria subbifurcataas a model species to explore the relative gut fullness from hatch to metamorphosis of wild larvae, and compared these values with those of laboratory-reared larvae fed at maximum rates. Ingestion rates of most wild larvae were above starvation levels but below the maximum feeding levels of laboratory-reared larvae. Twenty-six percent of freshly-hatched wild larvae and 11% of large, pre-settlement wild larvae had insufficient food in their stomach to satisfy metabolic requirements. These results, taken on their own, are consistent with the much hypothesized increased foraging performance and survival of larger larvae relative …

Microspore Wall Morphogenesis And Orbicule Ultrastructure Of Isoetes, Khalid Alarid

Biological Sciences Theses & Dissertations

The microspore wall morphogenesis and orbicule ultrastructure of Isoetes were studied using electron microscopy. Microspore wall morphogenesis in five species of Isoetes (I. appalachiana, I. engelmannii, I. hyemalis, I. piedmontana, and an undescribed species from York Co., VA, USA) was studied using scanning and transmission electron microscopy. Results show that they generally have the same developmental stages in terms of microspore wall morphogenesis. The mature microspore wall consisted of four layers: perispore, paraexospore, exospore and endospore. Paraexospore formation began during the tetrad stage. The exospore was then formed between the paraexospore and the plasma membrane. During the free spore …

Correlation Of Eastern Wild Turkey Poult:Hen Ratios With Population Indices To Detect Reproductive Density Dependence, Jay D. Mcghee, Jim Berkson

Virginia Journal of Science

Knowledge of how density affects population growth is important for the harvest management of wild turkey. Unfortunately, available time-series are often too short for statistical detection of density dependence. The correlation between wild turkey recruitment and population size was assessed using data from 7 state wildlife agencies, circumventing the problem of short time-series by using multiple datasets. Correlation coefficients were calculated between surveyed poult:hen ratios and harvest-based population indices for 31 geographic or harvest management regions. Estimated correlation coefficients were tested for homogeneity to determine if an average correlation could be calculated. Correlation coefficients for the 29 regions ranged from …

Seasonal Variation In Diet Of The Cotton Rat (Sigmodon Hispidus) Based On Fecal Analysis, Lynn A. Walker

Biological Sciences Theses & Dissertations

Cotton rats, Sigmodon hispidus, live in oldfields, habitats with a variety of mostly herbaceous plants. Based on other studies, the hispid cotton rat eats predominantly grasses, but grasses rarely are the only food. Fecal samples were collected each month during an ongoing capture-mark-release demographic study of the rodent community at a location in southern Chesapeake, Virginia. In the lab, five fecal pellets per animal were stained, placed on a microscope slide, and covered with starch-gel medium and coverslip. Then a clear nail polish was applied to produce a semi-permanent slide. Using a microscope and a set of reference slides, plant …

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2006), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

Macrobenthic communities of the Elizabeth River watershed have been quantitatively sampled since summer 1999. This report presents the data from the eigth year of sampling in 2006. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. (2) To conduct trend analyses on long-term data at 14 fixed-point stations to relate temporal trends in the benthic communities to changes in water and/or sediment quality. Trend analyses will be updated annually …

Evidence For Disease Mediated Extinction: Correlation Between An Introduced Pathogen And Extinction Of Rattus Macleari On Christmas Island, Kelly B. Wyatt

Biological Sciences Theses & Dissertations

The Durham Collection and the Cambridge and Oxford University Museums provided the materials to investigate the possibility that the extinction of indigenous rats of Christmas Island was a result of disease introduced by infected ship rats (R. rattus) in 1899. The collections of H.E. Durham in 1901-1902 reveal that R. macleari was present on Christmas Island up to then and includes specimens of R. rattus together with specimens that exhibit characteristics of both R. rattus and R. macleari. Durham's notes indicate both R. rattus and R. macleari specimens were heavily infected with trypanosomes at the time of collection. In …