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Full-Text Articles in Physical Sciences and Mathematics
Deep-Pelagic (0-3000m) Fish Assemblage Structure Over The Mid-Atlantic Ridge In The Area Of The Charlie-Gibbs Fracture Zone, April B. Cook
Deep-Pelagic (0-3000m) Fish Assemblage Structure Over The Mid-Atlantic Ridge In The Area Of The Charlie-Gibbs Fracture Zone, April B. Cook
Dissertations, Theses, and Masters Projects
Only a miniscule fraction of the world’s largest volume of living space, the ocean’s mid-water biome, has ever been sampled. As part of the International Census of Marine Life field project Mid-Atlantic Ridge Ecosystems (MAR-ECO), a discrete-depth trawling survey was conducted in 2009 aboard the NOAA ship Henry B. Bigelow to examine the pelagic faunal assemblage structure and distribution over the Charlie-Gibbs Fracture Zone (CGFZ) of the northern Mid-Atlantic Ridge. This is the first MAR-ECO project aimed specifically at describing diel vertical migration as a distributional phenomenon. Discrete-depth sampling from 0-3000 m was conducted during both day and night in …
The Effects Of Seagrass Species And Trophic Interactions In Experimental Seagrass Communities, Althea F. P. Moore
The Effects Of Seagrass Species And Trophic Interactions In Experimental Seagrass Communities, Althea F. P. Moore
Dissertations, Theses, and Masters Projects
No abstract provided.
The Role Of Copepods And Heterotrophic Dinoflagellates In The Production Of Dissolved Organic Matter And Inorganic Nutrients, Grace Kathleen Saba
The Role Of Copepods And Heterotrophic Dinoflagellates In The Production Of Dissolved Organic Matter And Inorganic Nutrients, Grace Kathleen Saba
Dissertations, Theses, and Masters Projects
Zooplankton play a key role in the cycling of dissolved organic matter (DOM) and inorganic nutrients. The factors that affect these processes, however, are not fully understood. I measured the effects of various diets on DOM and inorganic nutrient production by the copepod Acartia tonsa and the heterotrophic dinoflagellate Oxyrrhis marina, and explored the mechanisms of nutrient release from copepods. Copepods feeding on a mixed diet, the preferred diet of most copepods, had significantly lower dissolved organic carbon (DOC), ammonium (NH4+), and total dissolved nitrogen (TDN) release rates compared to feeding on a carnivorous or herbivorous diet. Thus, copepod feeding …
The Life History Of Longnose Gar, Lepisosteus Osseus, An Apex Predator In The Tidal Waters Of Virginia, Patrick E. Mcgrath
The Life History Of Longnose Gar, Lepisosteus Osseus, An Apex Predator In The Tidal Waters Of Virginia, Patrick E. Mcgrath
Dissertations, Theses, and Masters Projects
Longnose gar (Lepisosteus osseus) inhabit all of the major tributaries of Chesapeake Bay in Virginia, extending from fresh to estuarine waters. Literature concerning longnose gar from tidal environments is limited and this is study concerns important aspects of the life history (e.g., growth, reproduction, dimorphism, movements, and diet). Age, growth, and reproduction are important life history aspects for understanding the biology of fishes and may be affected by the environment in which an individual lives. This study found no differences in the age, growth, and fecundity parameters between longnose gar from tidal portions of Chesapeake Bay tributaries and previous studies …
Quantifying The Ecosystem Role Of A Suspension And A Facultative Deposit Feeding Bivalve In The New River Estuary, Nc: With Responses To Changes In Nutrient And Sediment Inputs, Heather Marie Wiseman
Quantifying The Ecosystem Role Of A Suspension And A Facultative Deposit Feeding Bivalve In The New River Estuary, Nc: With Responses To Changes In Nutrient And Sediment Inputs, Heather Marie Wiseman
Dissertations, Theses, and Masters Projects
No abstract provided.
Copepod Carcasses, Mortality And Population Dynamics In The Tributaries Of The Lower Chesapeake Bay, David Thomas. Elliott
Copepod Carcasses, Mortality And Population Dynamics In The Tributaries Of The Lower Chesapeake Bay, David Thomas. Elliott
Dissertations, Theses, and Masters Projects
Several studies have documented the occurrence of substantial numbers of zooplankton carcasses in marine field samples. However, the potential effect of carcasses on conclusions resting on zooplankton abundance estimates, and the reasons for carcass occurrence have been largely disregarded. Many field studies do not account for the presence of carcasses in their sampling methodology. Zooplankton carcasses in situ are significant for several reasons. as concentrated particles of organic matter in the water column, zooplankton carcasses can be important vehicles for organic matter transport and hotspots of microbial abundance and activity. If dead animals are treated alive, carcasses could bias the …
Habitat Complexity And Habitat Function Of Native (Crassostrea Virginica) And Non-Native (C. Ariakensis) Oysters In The Chesapeake Bay Region, Heather D. Harwell
Habitat Complexity And Habitat Function Of Native (Crassostrea Virginica) And Non-Native (C. Ariakensis) Oysters In The Chesapeake Bay Region, Heather D. Harwell
Dissertations, Theses, and Masters Projects
Complex oyster reefs created by the Eastern oyster, Crassostrea virginica, though once prominent features of the Chesapeake Bay region, have become relatively scarce in comparison to historic descriptions. This decline, caused by a combination of overfishing, disease, habitat destruction and pollution, this decline continues despite substantial restoration efforts that have spanned decades. In response to this decline, the states of Virginia and Maryland considered the intentional introduction of the non-native Suminoe oyster, C. ariakensis. Previous studies questioned the reef-building capability of this Crassostrea species, which may affect its habitat function. Through a combination of field and mesocosm studies, I examined …
Anthropogenic Causes Of Copepod Mortality And Bacterial Decomposition Of Copepod Carcasses, Samantha L. Bickel
Anthropogenic Causes Of Copepod Mortality And Bacterial Decomposition Of Copepod Carcasses, Samantha L. Bickel
Dissertations, Theses, and Masters Projects
Although zooplankton carcasses can be quite prevalent within aquatic systems, they have largely been overlooked in most zooplankton population studies. Anthropogenic stressors can potentially increase the overall abundance of carcasses on a local scale. Once a carcass is present within a system, the fate of its biomass is of considerable interest as it may be remineralized within the water column or transported to depth. Through the collection of field samples I assessed the possibility of an anthropogenic stressor (boat-generated turbulence) as a potential source of nonconsumptive mortality. I also conducted a series of laboratory experiments to monitor the decomposition of …
Multi-System Analysis Of Nitrogen Use By Phytoplankton And Heterotrophic Bacteria, Paul B. Bradley
Multi-System Analysis Of Nitrogen Use By Phytoplankton And Heterotrophic Bacteria, Paul B. Bradley
Dissertations, Theses, and Masters Projects
Traditional measurements of phytoplankton N uptake have been confounded by bacterial retention on filters used in 15N uptake studies, and such methodological obstacles have limited our understanding of phytoplankton-bacterial interactions regarding N cycling. In this research, uptake of various inorganic and organic N substrates by phytoplankton and bacteria was measured in several marine ecosystems using two distinct approaches: size fractionation into phytoplankton and bacterial size classes, and flow cytometric (FCM) sorting of autotrophic cells. Comprehensive assessments of N uptake dynamics were conducted in Chesapeake Bay, the Mid-Atlantic Bight, and Raunefjord, Norway, with supplementary data collected from the York River, Virginia …
Investigating The Relationships Between Recruitment Indices And Estimates Of Adult Abundance For Striped Bass, Weakfish, And Atlantic Croaker, Justine R. Woodward
Investigating The Relationships Between Recruitment Indices And Estimates Of Adult Abundance For Striped Bass, Weakfish, And Atlantic Croaker, Justine R. Woodward
Dissertations, Theses, and Masters Projects
Establishing the relationships between recruitment indices and estimates of adult abundance using fishery-independent data continues to remain one of the principal challenges faced by fisheries scientists due to the lack of concurrent monitoring programs designed to target different life stages of the same species. In Chesapeake Bay, however, multiple, fishery-independent surveys currently monitor the relative abundance of YOY and adult fishes. Using the available data from these surveys, the relationships between estimates of relative abundance for young-of-year and adults of striped bass (Morone saxatilis), weakfish (Cynoscion regalis), and Atlantic croaker (Micropogonias undulatus) were examined. Year-class strength was reflected in subsequent …
Egg Capsule Hatching Success In Rapana Venosa And Urosalpinx Cinerea In Relation To Temperature And Salinity, Stephanie M. Gera
Egg Capsule Hatching Success In Rapana Venosa And Urosalpinx Cinerea In Relation To Temperature And Salinity, Stephanie M. Gera
Dissertations, Theses, and Masters Projects
The maintenance of a population within the geographic range is influenced by the physical and environmental conditions under which breeding occurs. It is hypothesized that environmental conditions under which egg capsules are successfully hatched will influence the range of potential habitat of the invasive veined rapa whelk, Rapana venosa, and the native Atlantic oyster drill, Urosalpinx cinerea, in the Chesapeake Bay. This study examines the environmental conditions of temperature, salinity, and the time of deposition of egg capsules within the reproductive period (here quantified as cumulative number of day degrees at egg capsule deposition). The range of R. venosa and …
Hydrography And Phytoplankton Distribution In The Amundsen And Ross Seas, Glaucia M. Fragoso
Hydrography And Phytoplankton Distribution In The Amundsen And Ross Seas, Glaucia M. Fragoso
Dissertations, Theses, and Masters Projects
The phytoplankton of the Ross Sea have been intensively studied during the last decade, as opposed to the Amundsen Sea, where virtually nothing is known about phytoplankton taxonomy and distribution. Blooms in the Ross Sea are usually composed of diatoms and the prymnesiophyte Phaeocystis antarctica; diatoms are often dominant in strongly stratified waters during the summer, whereas P. antarctica usually dominates in less stratified waters in the south-central polynya during spring. This study focused on understanding the environmental variables that influence the spatial patterns of phytoplankton assemblages during late summer and early fall, 2007, and late spring and early summer, …
A Numerical Modeling Study On Barotropic And Baroclinic Responses Of The Chesapeake Bay To Hurricane Events, Kyoung-Ho Cho
A Numerical Modeling Study On Barotropic And Baroclinic Responses Of The Chesapeake Bay To Hurricane Events, Kyoung-Ho Cho
Dissertations, Theses, and Masters Projects
The barotropic and baroclinic responses of the Chesapeake Bay to forcings from two hurricanes were investigated by using unstructured-grid three-dimensional hydrodynamic models. The model domain includes Chesapeake Bay proper, the tributaries, and its extended continental shelf in the mid-Atlantic Bight. Two hurricanes were studied: Hurricane Floyd of September, 1999 and Hurricane Isabel of September, 2003, both of which made landfall within 100 km of the Chesapeake Bay mouth. Hurricane Floyd in 1999 passed through the entrance of the Bay from southwest to northeast along the coastlines of Virginia as a Category 1 storm, whereas Hurricane Isabel in 2003 made landfall …
Assessing Genetic Variation Within And Among Native Populations And Hatchery Stocks Of Crassostrea Ariakensis Using Microsatellite Markers, Jie Xiao
Dissertations, Theses, and Masters Projects
Assessing genetic variation within and among native populations and hatchery stocks of Crassostrea ariakensis using microsatellite markers In response to the dramatic decline of eastern oyster (Crassostrea virginica) populations in the Chesapeake Bay, introduction of the non-native Asian oyster Crassostrea ariakensis has been proposed. Currently several hatchery stocks of C. ariakensis, derived from a few wild populations along the coast of Japan and China, are being maintained in U.S. hatcheries in the Pacific northwest and on the east coast. In recent years, as the risks of the proposed introduction are being assessed, these hatchery animals have been widely used for …
Mesopelagic Zooplankton Feeding Ecology And Effects On Particle Repackaging And Carbon Transport In The Subtropical And Subarctic North Pacific Ocean, Stephanie E. Wilson
Mesopelagic Zooplankton Feeding Ecology And Effects On Particle Repackaging And Carbon Transport In The Subtropical And Subarctic North Pacific Ocean, Stephanie E. Wilson
Dissertations, Theses, and Masters Projects
Differences in zooplankton community structure and diet within the mesopelagic zone (base of euphotic zone to 1000 m) play a key role in affecting the efficiency by which organic matter is exported to depth, but how the structure of mesopelagic food webs change with depth or location is poorly known. I examined how mesopelagic zooplankton affect particle export in an oligotrophic (Hawaii Ocean Time-series site ALOHA) compared to a mesotrophic (Japanese time series site K2) open-ocean system. In the first part of the study, I investigated how fecal pellet characteristics change with depth in order to quantify the extent of …
Effects Of Shoreline Development And Oyster Reefs On Benthic Communities In Lynnhaven, Virginia, Amanda Sue Lawless
Effects Of Shoreline Development And Oyster Reefs On Benthic Communities In Lynnhaven, Virginia, Amanda Sue Lawless
Dissertations, Theses, and Masters Projects
Shoreline hardening and construction of restoration oyster reefs are occurring at rapid rates throughout Chesapeake Bay and little research has been conducted to determine whether installment of a hardened shoreline and oyster reef placement has an effect on the surrounding benthic infaunal communities. I investigated the effects of shoreline development and oyster reefs on benthic communities in Lynnhaven, Virginia. Throughout Lynnhaven, I determined the effects of shoreline type (natural marsh, oyster reef, rip-rap and bulkhead), sediment grain size, Total Organic Carbon/Total Nitrogen (TOC/TN) of the sediment, and predation (caging study) on density, biomass, and diversity of benthic infauna. An information-theoretic …
Natural Mortality Of Blue Crab: Estimation And Influence On Population Dynamics, David A. Hewitt
Natural Mortality Of Blue Crab: Estimation And Influence On Population Dynamics, David A. Hewitt
Dissertations, Theses, and Masters Projects
The blue crab Callinectes sapidus supports one of the most important fisheries in the Chesapeake Bay and is the leading contributor to blue crab landings in the United States. Assessment and management of blue crab stocks has been hampered by a lack of estimates of natural mortality rates, a key parameter in assessment models. In Chapter 2, we demonstrate that the approach used for estimating natural mortality that had been used in past assessments was flawed, and provide justification for a superior alternative. In Chapter 3, we synthesize our current understanding of natural mortality rates in adult blue crab and …
Community Dynamics In Submersed Aquatic Vegetation: Intermediate Consumers As Mediators Of Environmental Change, James G. Douglass
Community Dynamics In Submersed Aquatic Vegetation: Intermediate Consumers As Mediators Of Environmental Change, James G. Douglass
Dissertations, Theses, and Masters Projects
Natural ecosystems are strongly affected by changes in resource supply (bottom-up forces) and by changes in upper trophic levels (top-down forces). The extent to which these processes impact a system depends largely on the responses of organisms at middle trophic levels. In seagrass beds, a group of mid-level consumers known as mesograzers form a critical link in the chain of impact, connecting seagrass and epiphytic algae with predatory fishes and crustaceans. I observed dramatic seasonal and interannual changes in mesograzer abundance and species composition in eelgrass (Zostera marina) beds of lower Chesapeake Bay, Virginia, and endeavored to explain the top-down …
Age, Growth, And Demography Of The Sandbar Shark, Carcharhinus Plumbeus, Over Temporal And Spatial Scales, Jason G. Romine
Age, Growth, And Demography Of The Sandbar Shark, Carcharhinus Plumbeus, Over Temporal And Spatial Scales, Jason G. Romine
Dissertations, Theses, and Masters Projects
Numbers of sandbar sharks, Carcharhinus plumbeus, in the Northwest Atlantic have experienced drastic declines since the early 1980's reaching their minima during the early 1990's. Catch rates in the early 1990's were a mere 25% of those during the 1980's. Such drastic reductions in other fish stocks have often caused compensatory responses, most notably the cod stocks in the Northwest Atlantic. Compensatory responses in depressed populations may include decreased natural mortality, increased fecundity, or increased growth rates. Compensation for population fluctuations below carrying capacities have been recognized for many terrestrial and oceanic r-selected organisms, but few instances have been noted …
Bottom-Up And Top-Down Controls On Sedimentary Ecosystem Functioning In A Seagrass Habitat, Amanda C. Spivak
Bottom-Up And Top-Down Controls On Sedimentary Ecosystem Functioning In A Seagrass Habitat, Amanda C. Spivak
Dissertations, Theses, and Masters Projects
Coastal seagrass ecosystems are complex habitats that are increasingly influenced by human perturbations. Disturbances that affect the strength of bottom-up (i.e. resource availability) and top-down (i.e. consumer) controls may also influence biomass distribution between trophic levels, sediment biogeochemistry, and seagrass ecosystem metabolism. Here, I experimentally tested how top-down and bottom-up perturbations interact with community structure (diversity, food chain length of epibenthic consumers) to alter sediment biogeochemistry and ecosystem metabolism in an experimental eelgrass (Zostera marina ) system. My data indicated that resource availability influenced SOM composition and ecosystem metabolism. Light availability tended to be a stronger determinant of SOM composition …
Interspecific Interactions In Oyster Reef Communities: The Effect Of Established Fauna On Oyster Larval Recruitment, Brian B. Barnes
Interspecific Interactions In Oyster Reef Communities: The Effect Of Established Fauna On Oyster Larval Recruitment, Brian B. Barnes
Dissertations, Theses, and Masters Projects
The behaviors of oyster larvae are difficult to monitor or experimentally manipulate, especially in field conditions. As a result, little is known of the fate of oysters in the larval portion of their life cycle, prior to recruitment. At the transition from pelagic larvae to benthic adults, larvae are likely to come into contact with many invertebrates resident on oyster reefs. Of these, fouling epifauna are generally believed to reduce the settlement of interspecific larvae through competitive exclusion and predation. Studies of these interactions, however, often utilize artificial settlement panels, which can exhibit different recruitment patterns to those observed on …
Zooplankton Community Structure In A Cyclonic And Mode-Water Eddy In The Sargasso Sea, Bethany Rose Eden
Zooplankton Community Structure In A Cyclonic And Mode-Water Eddy In The Sargasso Sea, Bethany Rose Eden
Dissertations, Theses, and Masters Projects
Recent evidence suggests that mesoscale eddies are an important mechanism for supplying nutrients to the surface waters of oligotrophic gyres. However, little is known about the biological response to these physical perturbations. Because mesozooplankton play a key role in food-web interactions and the flux of carbon and other elements from surface waters, changes in mesozooplankton community structure can affect biogeochemical cycling. During the summers of 2004 and 2005, respectively, we followed the development of a cyclonic eddy and an anti-cyclonic mode-water eddy in the Sargasso Sea. Zooplankton tows were conducted across both eddies using a Multiple Opening and Closing Net …
Trophic Ecology And Growth Dynamics Of Striped Bass (Morone Saxatilis) In Chesapeake Bay, With Reference To Mycobacteriosis, Kathleen Anne Mcnamee
Trophic Ecology And Growth Dynamics Of Striped Bass (Morone Saxatilis) In Chesapeake Bay, With Reference To Mycobacteriosis, Kathleen Anne Mcnamee
Dissertations, Theses, and Masters Projects
No abstract provided.
Hypoxia And Macoma Balthica: Ecological Effects On A Key Infaunal Benthic Species, William Christopher Long
Hypoxia And Macoma Balthica: Ecological Effects On A Key Infaunal Benthic Species, William Christopher Long
Dissertations, Theses, and Masters Projects
Hypoxia, low dissolved oxygen, is an important environmental stressor in estuarine systems. In this dissertation, I examine the effects of hypoxia on the macrobenthic communities of the York and Rappahannock Rivers, Chesapeake Bay, USA, and in particular its effects on the infaunal clam Macoma balthica. A survey of the macrobenthic community was performed using box-coring before and after hypoxia in 2003 and 2004 in both rivers. Hypoxia was associated with a change in the macrobenthic community towards smaller, shorter-lived, opportunistic species; and a substantial decrease in biomass. M. balthica recruited into all areas of the river but suffered local extinction …
Inactive Sulfide Mounds Of The Manus Basin: Invertebrate Composition And Potential For A Chemoautotrophic Food Web, Kristin Lynn Erickson
Inactive Sulfide Mounds Of The Manus Basin: Invertebrate Composition And Potential For A Chemoautotrophic Food Web, Kristin Lynn Erickson
Dissertations, Theses, and Masters Projects
No abstract provided.
Feeding Ecology Of Atlantic Menhaden (Brevoortia Tyrannus) In Chesapeake Bay, Patrick D. Lynch
Feeding Ecology Of Atlantic Menhaden (Brevoortia Tyrannus) In Chesapeake Bay, Patrick D. Lynch
Dissertations, Theses, and Masters Projects
No abstract provided.
Biogeochemistry And Phytoplankton Dynamics In The Ross Sea, Antarctica, Amy Rebecca Shields
Biogeochemistry And Phytoplankton Dynamics In The Ross Sea, Antarctica, Amy Rebecca Shields
Dissertations, Theses, and Masters Projects
The Ross Sea, Antarctica seasonal phytoplankton bloom is one of the largest in the Southern Ocean. This project focuses on the biological pump, which removes carbon from the surface ocean to the deep ocean through the settling of particulate organic matter, the advection of dissolved organic carbon, and active flux due to vertical migration of zooplankton. The objective of this study was to focus on three interrelated components of the biological pump including sedimentation, photosynthetic rates and grazing. The study was conducted in coordination with the Interannual Variability in the Antarctic-Ross Sea program, which covered the time period between 2001--2005. …
A Molecular Technique For Specific Identification Of Western Atlantic Ocean Scombrids And An Analysis Of A Larval Scombrid Assemblage Off The Kona Coast Of Hawaii, Melissa A. Paine
A Molecular Technique For Specific Identification Of Western Atlantic Ocean Scombrids And An Analysis Of A Larval Scombrid Assemblage Off The Kona Coast Of Hawaii, Melissa A. Paine
Dissertations, Theses, and Masters Projects
No abstract provided.
The Effects Of Climate Change On The Population Ecology Of The Atlantic Surf Clam, Spisula Solidissima, In The Middle Atlantic Bight, Adriana Picariello
The Effects Of Climate Change On The Population Ecology Of The Atlantic Surf Clam, Spisula Solidissima, In The Middle Atlantic Bight, Adriana Picariello
Dissertations, Theses, and Masters Projects
No abstract provided.
Incorporating Space Into Stock Assessments Of Marine Species, John F. Walter
Incorporating Space Into Stock Assessments Of Marine Species, John F. Walter
Dissertations, Theses, and Masters Projects
Spatial management of marine resources requires population dynamic parameters in much greater spatial detail than traditional stock assessments provide. This dissertation presents a suite of methods to improve the spatial prediction of population abundance, fishing and natural mortality and to make greater use of commercial catch data. The main objectives of this dissertation are to determine the efficacy of using the vast amount of data collected by on-board observers on commercial vessels in model-based estimation of abundance and to use the spatial autocorrelation to improve resource mapping and abundance estimation. The first paper presents a methodology for improving variogram estimation …