Physical Sciences and Mathematics Commons^™

Absorption Efficiencies And Biochemical Fractionation Of Assimilated Compounds In The Cold Water Appendicularian Oikopleura Vanhoeffeni, Alexander B. Bochdansky, Don Deibel, Richard B. Rivkin

OES Faculty Publications

Using Ge-68:C-14 dual-labeling, we investigated the absorption efficiency of diatom carbon for the cold water appendicularian Oikopleura vanhoeffeni. The absorption efficiency of bulk carbon (mean = 67%) was not influenced by body size or ingestion rate. For the first time for a pelagic tunicate, food and feces were fractionated into their major biochemical constituents (i.e., low-molecular-weight compounds, lipid, protein, and polysaccharide), allowing calculation of absorption efficiencies for each fraction. Low-molecular-weight compounds and proteins were preferentially absorbed over lipids and polysaccharides. However, predicted C:N ratios of the fecal pellets of O. vanhoeffeni were in the lower range of C:N ratios …

Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz

Graduate School of Oceanography Faculty Publications

Practical autonomous robotic vehicles require dependable methods for accurately identifying course or roadway boundaries. The authors have developed a method to reliably extract the boundary line using simple dynamic thresholding, noise filtering, and blob removal. This article describes their efforts to apply this procedure in developing an autonomous vehicle.

Accurate Classification Of Juvenile Weakfish Cynoscion Regalis To Estuarine Nursery Areas Based On Chemical Signatures In Otoliths, Simon R. Thorrold, Cynthia M. Jones, Peter K. Swart, Timothy E. Targett

OES Faculty Publications

We investigated the ability of trace element and isotopic signatures in otoliths to record the nursery areas of juvenile (young-of-the-year) weakfish Cynoscion regalis from the east coast of the USA. Juvenile C. regalis were captured with otter trawls at multiple sites in Doboy Sound (Georgia), Pamlico Sound (North Carolina), Chesapeake Bay (Virginia), Delaware Bay (Delaware) and Peconic Bay (New York), from July to September 1996. One sagittal otolith from each specimen was assayed for Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca ratios using inductively coupled plasma mass spectrometry (ICP-MS), while delta 13 C and delta 18 O values from the other sagittal …

Laser In-Situ Scattering And Transmissometer (Lisst) Observations In Support Of The Sensor Insertion System Duck, Nc October, 1997, Grace M. Massey, Carl T. Friedrichs

Reports

The objective of this portion of the study was to collect LIS ST time series at times corresponding to collection of pumped samples of suspended sediment across the width of the surf zone during a major field experiment called SandyDuck '97. The pumped samples were analyzed for total percent sand (>60 micron), total percent mud (0.8 - 60 micron), organic content and sand size distribution. The LISST measures the particle size distribution from 5-500 microns. The purpose was to provide a high quality data set of pumped samples with which to later test the sensitivity of indirect measurements of …

Fall 1998, Nsu Oceanographic Center

Currents

No abstract provided.

Chemical Signals From Submarine Fluid Advection Onto The Continental Shelf, W. S. Moore, Timothy J. Shaw

Faculty Publications

No abstract provided.

Summer 1998, Nsu Oceanographic Center

Currents

No abstract provided.

Estimate Of Bottom And Surface Stress During A Spring-Neap Tide Cycle By Dynamical Assimilation Of Tide Gauge Observatons In The Chesapeake Bay, Y. H. Spitz, J. M. Klinck

CCPO Publications

Dynamical assimilation of surface elevation from tide gauges is investigated to estimate the bottom drag coefficient and surface stress as a first step in improving modeled tidal and wind-driven circulation in the Chesapeake Bay. A two-dimensional shallow water model and an adjoint variational method with a limited memory quasi-Newton optimization algorithm are used to achieve this goal. Assimilation of tide gauge observations from 10 permanent stations in the Bay and use of a two-dimensional model adequately estimate the bottom drag coefficient, wind stress, and surface elevation at the Bay mouth. Subsequent use of these estimates in the circulation model considerably …

Separating Baroclinic Flow From Tidally Induced Flow In Estuaries, Chunyan Li, Arnoldo Valle-Levinson, Kuo Chuin Wong, Kamazima M. M. Lwiza

CCPO Publications

A simple method is used to separate the tidally induced and density-driven subtidal flows in a coastal plain estuary. This method is applicable to weak wind conditions and to systems with appreciable fortnightly variation of tidal amplitude. The baroclinic density-driven motion is assumed to depend on the river discharge, which generates a horizontal density gradient, and is weakened by vertical mixing, which in turn depends on tidal forcing. The barotropic tidally induced motion is assumed to be a function of the tidal amplitude. By Taylor series expansions, two equations are obtained. These equations show the dependence of the tidally induced …

Spring 1998, Nsu Oceanographic Center

Currents

No abstract provided.

Studies Of Warm-Core Rings Using A Particle-In-Cell Method, John James Holdzkom Ii

OES Theses and Dissertations

A particle-in-cell (PIC) model is developed and applied to problems involving the evolution of warm-core rings. Such models are a hybrid of conventional Eulerian and Lagrangian models. They are ideally suited for problems in which a lower layer outcrops to the surface, such as at the boundary of a ring.

The model is developed in three implementations. First, for purposes of model validation, a reduced gravity model is described. The PIC model reproduces the essential characteristics of analytical solutions to the reduced gravity equations and integral invariants are conserved to a high degree. Next, a 1.5-layer model is developed and …

Modeling Environmental Effects On Msx Prevalence And Intensity In Eastern Oyster (Crassostrea Virginica) Populations, Michelle Christine Paraso

OES Theses and Dissertations

An oyster population model coupled with a model for Haplosporidium nelsoni, the causative agent of the oyster disease MSX, was used with salinity time-series constructed from Delaware River flow measurements to study environmentally-induced variations in the annual cycle of this disease. Simulations with this model were designed to investigate the effect of increased or decreased spring freshwater discharge, the timing of high freshwater runoff, the presence or absence of a fall or late spring phytoplankton bloom, and the occurrence of a warm winter on MSX prevalence and intensity in Delaware Bay oyster populations. Model simulations for the lower Bay site …

1998 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Heat And Salt Changes On The Continental Shelf West Of The Antarctic Peninsula Between January 1993 And January 1994, John M. Klinck

CCPO Publications

Hydrographic measurements from four cruises between January 1993 and January 1994 over the continental shelf west of the Antarctic Peninsula allow analysis of seasonal changes in heat and salt content of this region. Changes above the permanent pycnocline (about 150 m) follow a seasonal pattern of cooling and increasing in salt from summer to winter and warming and freshening from winter to summer. These near-surface changes expressed as net heating or salting rate, were above 80 W m(-2) and 4 mg salt m(-2) s(-1). The year to year difference was small compared to the seasonal changes. There was no seasonal …

Understanding The Success And Failure Of Oyster Populations: The Importance Of Sampled Variables And Sample Timing, Thomas M. Soniat, Eric N. Powell, Eileen E. Hofmann, John M. Klinck

CCPO Publications

One of the primary obstacles to understanding why some oyster populations are successful and others are not is the complex interaction of environmental variables with oyster physiology and with such population variables as the rates of recruitment and juvenile mortality. A numerical model is useful in investigating how population structure originates out of this complexity. We have monitored a suite of environmental conditions over an environmental gradient to document the importance of short time-scale variations in such variables as food supply, turbidity, and salinity. Then, using a coupled oyster disease population dynamics model, we examine the need for short rime-scale …

Sigma Coordinate Pressure Gradient Errors And The Seamount Problem, George L. Mellor, Lie-Yauw Oey, Tal Ezer

CCPO Publications

In a recent paper by Mellor et al., it was found that, in two-dimensional (x, z) applications with finite horizontal viscosity and zero diffusivity, the velocity error, associated with the evaluation of horizontal density or pressure gradients on a sigma coordinate grid, prognostically disappeared, leaving behind a small and physically insignificant distortion in the density field. The initial error is numerically consistent in that it decreases as the square of the grid increment size. In this paper, we label this error as a sigma error of the first kind. In three-dimensional applications, the authors have encountered an error that did …

Integrable Unsteady Motion With An Application To Ocean Eddies, A. D. Kirwan Jr., Bruce L. Lipphardt

CCPO Publications

Application of the Brown-Samelson theorem, which shows that particle motion is integrable in a class of vorticity-conserving, two-dimensional incompressible hows, is extended here to a class of explicit time dependent dynamically balanced flows in multilayered systems. Particle motion for nonsteady two-dimensional flows with discontinuities in the vorticity or potential vorticity fields (modon solutions) is shown to be integrable. An example of a two-layer modon solution constrained by observations of a Gulf Stream ring system is discussed.

Identification Of Past Climate Variability Of The Eastern Pacific Ocean Using Both D13c And D18o Records In Corals From Clipperton Atoll (1994-1906), Lei Ren

Geology Theses and Dissertations

The ENSO (El Nino and the Southern Oscillation) is a fundamental ocean-atmosphere phenomenon that dominates interannual global climate variability. Reconstructing past ENSO events is therefore important for documenting and understanding the past behavior of the global climate system and enabling us to predict future climate change. However, the present understanding of ENSO events has been mainly based on the instrumental record of Pacific climate which provides detailed data only for the past few decades. Recent studies have shown that the stable isotope record in coral skeletons can be used as a valuable indicator of paleoclimatic changes in tropical regions, and …

1998 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

1998 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

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.

Wind Interaction With Buoyant Plumes On The Inner Continental Shelf, Sarah E. Rennie

Dissertations, Theses, and Masters Projects

The characteristics and effects of intrusions of estuarine outflow over the inner shelf were examined, based on hydrographic and meteorological observations obtained during the "Coastal Ocean Processes" (CoOP'94) field experiment located off the Outer Banks at Duck, North Carolina. The episodic presence of distinct low salinity water masses issuing from the Chesapeake Bay created an intermittent baroclinic coastal current along the North Carolina coast. Under low wind conditions, this current occupied the upper half of the water column within 9 km of the coast. The plume was bounded by a distinct southward-propagating front, a region offshore of high horizontal salinity …

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}st{rcub}& = …

Age, Growth, And Mortality Of Black Drum, Pogonias Cromis, In The Chesapeake Bay Region, Cynthia M. Jones, Brian Wells

OES Faculty Publications

We used otolith ageing to describe the population dynamics of black drum, Pogonias cromis, collected over a three-year period from the Chesapeake Bay region's commercial and recreational fisheries. Black drum average age, total length, and weight were 26 years, 109.5 cm, and 22.1 kg respectively. The oldest fish was 59 years and fish older than 50 years were present in the catch from 1990 to 1992. Growth in length slowed by age 20, whereas growth in weight did not slow until age 45. A von Bertalanffy growth function was fitted to our data (L(infinity) = 117.3 cm, …

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.

Iron In Ice Cores From Law Dome, East Antarctica: Implications For Past Deposition Of Aerosol Iron, R. Edwards, Peter N. Sedwick, Vin Morgan, C. F. Boutron, S. Hong

OES Faculty Publications

Total-dissolvable iron has been measured in sections of three ice cores from Law Dome, East Antarctica, and the results used to calculate atmospheric iron deposition over this region during the late Holocene and to provide a preliminary est. of aerosol iron deposition during the Last Glacial Maximum (LGM). Ice-core sections dating from 56-2730 BP (late Holocene) and ∼18 000 BP (LGM) were decontaminated using trace-metal clean techniques, and total-dissolvable iron was determined in the acidified meltwaters by flow-injection analysis. Our results suggest that the atmospheric iron flux onto the Law Dome region has varied significantly over time-scales ranging from seasonal …

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, …

Distribution, Partitioning And Fluxes Of Dissolved And Particulate Organic Carbon, Nitrogen And Phosphorus In The Eastern North Pacific And Southern Oceans, Ai Ning Loh

Dissertations, Theses, and Masters Projects

No abstract provided.

The Biogeochemical Cycling Of Dissolved Organic Nitrogen In Estuarine Sediments, David J. Burdige, Shilong Zheng

OES Faculty Publications

Benthic fluxes and pore-water profiles of dissolved organic nitrogen and carbon (DON and DOC, respectively) were determined in seasonal studies at contrasting sites in Chesapeake Bay. Pore-water dissolved organic matter (DOM) concentrations were elevated over bottom-water values, generally increased with depth, and ranged from 15 to similar to 160 μM for DON and ~200-2000 μM for DOC. Pore-water DOM concentrations and the C:N ratio of this material showed spatial (depth) and temporal changes that varied among the sites studied. These trends appeared to be related to differences in the types of sediment organic matter (SOM) undergoing remineralization, as well as …

Lead Isotopes And Selected Metals In Ice From Law Dome, Antarctica, K. J. R. Rosman, W. Chisholm, C. F. Boutron, S. Hong, R. Edwards, Vin Morgan, Peter N. Sedwick

OES Faculty Publications

The isotopic composition. of Pb and the concentrations of Pb, Ba and Bi were measured in selected ice-core samples from Law Dome, East Antarctica, to a depth of 1196 m. The range of concentrations found in decontaminated ice was 0.03-1.5 pg g^-1 for Pb, 0.9-6.1 pg g^-1 for Ba and 0.4-17 fg g^-1 for Bi, excluding the deepest sample which contained ∼1 ppm of rock dust. The abundances of all four stable lead isotopes were measured and gave ²⁰⁶Pb/²⁰⁷Pb ratios ≤ ∼1.23. A value of ²⁰⁸Pb/²⁰⁷Pb = 2.78 was measured in …