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Development Of Resistance To An Introduced Marine Pathogen By A Native Host, Susan E. Ford, David Bushek

Journal of Marine Research

In 1957–1959, the introduced protistan parasite, Haplosporidium nelsoni, killed 90–95% of the oysters (Crassostrea virginica) in lower Delaware Bay and about half of those in the upper bay. Shortly thereafter, H. nelsoni-caused mortality in the wild population of the lower bay declined, approximating that of first-generation selectively bred oysters. For nearly three decades thereafter no further change in survival of the wild population was evident, although steady improvement was achieved by continued selective breeding. Survival of the wild population is thought to have plateaued because the great majority of oysters inhabited the upper bay where they …

Effective Population Sizes Of Eastern Oyster Crassostrea Virginica (Gmelin) Populations In Delaware Bay, Usa, Yan He, Susan E. Ford, David Bushek, Eric N. Powell, Zhenmin Bao, Ximing Guo

Journal of Marine Research

Effective population size (N_e) is an important concept in population genetics as it dictates the rate of genetic change caused by drift. N_e estimates for many marine populations are small relative to the census population size. Small N_e in a large population may indicate high reproductive variance or sweepstakes reproductive success (SRS). The eastern oyster (Crassostrea virginica) may be prone to SRS due to its high fecundity and high larval mortality. To examine if SRS occurs in the eastern oyster, we studied N_e and genetic variation of oyster populations in Delaware Bay. …

Modeling The Dispersal Of Eastern Oyster (Crassostrea Virginica) Larvae In Delaware Bay, Diego A. Narváez, John M. Klinck, Eric N. Powell, Eileen E. Hofmann, John Wilkin, Dale B. Haidvogel

Journal of Marine Research

The interactions of circulation and growth processes in determining the horizontal distribution of eastern oyster (Crassostrea virginica) larvae in the Delaware Bay estuary were investigated with a coupled circulation-individual-based larvae model that used environmental conditions from the spawning seasons (mid-June to mid-September) of 1984, 1985, 1986, 2000, and 2001. Particles, representing oyster larvae, were released at five-day intervals from areas in Delaware Bay that correspond to natural oyster reefs. The simulated larval development time was used to estimate potential larval success, determined by the percent of larvae that successfully reached settlement size (330 μm) within the planktonic larval …

Reconciling Float-Based And Tracer-Based Estimates Of Lateral Diffusivities, Andreas Klocker, Raffaele Ferrari, Joseph H. Lacasce, Sophia T. Merrifield

Journal of Marine Research

Lateral diffusivities are computed from synthetic particles and tracers advected by a velocity field derived from sea-surface height measurements from the South Pacific, in a region west of Drake Passage. Three different estimates are compared: (1) the tracer-based “effective diffusivity” of Nakamura (1996), (2) the growth of the second moment of a cloud of tracer and (3) the single- and two-particle Lagrangian diffusivities. The effective diffusivity measures the cross-stream component of eddy mixing, so this article focuses on the meridional diffusivities for the others, as the mean flow (the ACC) is zonally oriented in the region. After an initial transient …

Intermittent Bioirrigation And Oxygen Dynamics In Permeable Sediments: An Experimental And Modeling Study Of Three Tellinid Bivalves, Nils Volkenborn, Christof Meile, Lubos Polerecky, Conrad A. Pilditch, Alf Norkko, Joanna Norkko, Judi E. Hewitt, Simon F. Thrush, David S. Wethey, Sarah A. Woodin

Journal of Marine Research

To explore the dynamic nature of geochemical conditions in bioirrigated marine permeable sediments, we studied the hydraulic activity of three tellinacean bivalve molluscs (the Pacific species Macoma nasuta and Macomona liliana, and the northern Atlantic and Pacific species Macoma balthica). We combined porewater pressure sensing, time-lapse photography and oxygen imaging to quantify the durations and frequencies of tellinid irrigation activity and the associated oxygen dynamics in the sediment. Porewater pressure records of all tellinids were dominated by intermittent porewater pressurization, induced by periodic water injection into the sediment through their excurrent siphons, which resulted in intermittent oxygen supply …

Deep Circulation In The Eastern South Pacific Ocean, Vincent Faure, Kevin Speer

Journal of Marine Research

We use an inverse method to compute the deep circulation in the eastern South Pacific Ocean, on isopycnal layers within the depth range of 1,000–3,000 m. The method gives probability density functions of the isopycnal and diapycnal velocities and diffusivities on a grid with a realistic eastern boundary, based on tracer fields. An oxygen consumption rate, assumed spatially constant, controls the solution effectiveness (minimum value of the model cost function) and the magnitude of the diffusivities. The isopycnal circulation is, by contrast, less dependent on the consumption rate. Direct deep float displacement data is used as a check on our …

The Role Of Larval Dispersal In Metapopulation Gene Flow: Local Population Dynamics Matter, Daphne M. Munroe, John .. Klinck, Eileen E. Hofmann, Eric N. Powell

Journal of Marine Research

The degree of genetic connectivity among populations in a metapopulation has direct consequences for species evolution, development of disease resistance, and capacity of a metapopulation to adapt to climate change. This study used a metapopulation model that integrates population dynamics, dispersal, and genetics within an individual-based model framework to examine the mechanisms and dynamics of genetic connectivity within a metapopulation. The model was parameterized to simulate four populations of oysters (Crassostrea virginica) from Delaware Bay on the mid-Atlantic coast of the United States. Differences among the four populations include a strong spatial gradient in mortality, a spatial gradient …

Oyster Food Supply In Delaware Bay: Estimation From A Hydrodynamic Model And Interaction With The Oyster Population, Eric N. Powell, Danielle A. Kreeger, Jason M. Morson, Dale B. Haidvogel, Zhiren Wang, Roger Thomas, Jennifer E. Gius

Journal of Marine Research

To evaluate oyster food supply, water samples were collected at fifteen sites in Delaware Bay nearmonthly in 2009 and 2010. Food was estimated as the sum of particulate protein, labile carbohydrate, and lipid. Delaware Bay shows a typical spring bloom, centered in March and April, with declining food supply thereafter into early fall, followed sporadically by a minor fall bloom. The geographic and temporal structure of food was more predictable in summer to early fall, and considerably less predictable in spring. Five variables each based on temperature and the spatial and temporal variability of temperature were significant contributors to a …

Evidence Of Vertical Coupling Between The Kuroshio Extension And Topographically Controlled Deep Eddies, Andrew D. Greene, D. Randolph Watts, Georgi G. Sutyrin, Hideharu Sasaki

Journal of Marine Research

Strong energy in the 30–60 day band was observed using 39 deep pressure and current records from the Kuroshio Extension System Study (KESS). Energy in this band accounted for 25–50% of the total deep-pressure variance and was strongest under the Kuroshio Extension jet axis. Often, deep-pressure anomalies propagated into the region from the north-northeast and locally intensified as they passed under and interacted with the Kuroshio Extension. The topographically controlled deep-pressure anomalies translate nearly along lines of constant f/H. Statistically significant coherence between 30–60 day upper- and deep-ocean streamfunction anomalies demonstrated that there was strong vertical coupling in that …

Adjustment Of A Wind-Driven Two-Layer System With Mid-Basin Topography, Magdalena Andres, Jiayan Yang, Young-Oh Kwon

Journal of Marine Research

A linear primitive equations model is used to simulate spin-up of a two-layer ocean bisected by a meridional ridge. The ocean is forced with steady zonal winds east of the ridge. When wind-driven barotropic planetary Rossby waves propagate across the ridge, barotropic and baroclinic anomalies are generated as the barotropic flow adjusts. These ridge-generated anomalies propagate westward from the ridge as planetary Rossby waves and their arrival along the basin's western boundary modulates the western boundary current (WBC) transport and vertical structure. Model results suggest that at short (<1 year) and long (>10 years) delay relative to a …

The Legacy Of Gordon Arthur Riley (1911–1985) And The Development Of Mathematical Models In Biological Oceanography, Thomas R. Anderson, Wendy C. Gentleman

Journal of Marine Research

Gordon Arthur Riley (1911–1985) is remembered for his pioneering work in the development of marine ecosystem models during the mid-20th century. Using models that were necessarily simple because of the limited understanding of plankton physiology at the time, as well as the fact that calculations had to be done by hand, Riley studied the processes that control plankton stocks, production, and nutrient cycling, notably at Georges Bank. His great achievement lay not so much in the simulation of plankton dynamics per se, but rather in bringing to the fore the concept of using modeling as a means of explaining …

Detailed Internal Wave Mixing Above A Deep-Ocean Slope, Hans Van Haren, Louis Gostiaux

Journal of Marine Research

Turbulent vertical eddy diffusivity (K_z) and dissipation rate (ε) are estimated between 0.5 and 50 m above the sloping side of Great Meteor Seamount, Canary Basin, using 101 moored temperature sensors, 1-mK precision, sampling at 1 Hz. Effectively, detailed observed time-depth temperature images are split in two: a statically stable and a turbulence image. Tides dominate the temperature variations, but the local bottom slope is supercritical to motions at semidiurnal frequencies. Averaged over a fortnight, the observed overall time-depth mean Kz = 3±1 × 10^–3 m² s^–1 and ε = 1.5±0.7 × 10^–7 W …

A Tribute To Doreen Orciari, George Veronis

Journal of Marine Research

With her retirement this year Doreen Orciari will end her 36th year at Yale, 32 of them as editorial assistant at the Journal of Marine Research. She came to work for me as my secretary in December, 1976, when I was chairman of the Department of Geology and Geophysics. It turns out that she was the best Christmas present that I have ever had. Doreen was born and raised as an Irish Catholic in New Haven and spent her youth in somewhat of a dysfunctional family. She spent 12 years amid Catholic nuns who served to add structure to her …

The Rise And Fall Of Crassostrea Virginica Oyster Reefs: The Role Of Disease And Fishing In Their Demise And A Vignette On Their Management, Eric N. Powell, John M. Klinck, Kathryn Ashton-Alcox, Eileen E. Hofmann, Jason Morson

Journal of Marine Research

We describe a model designed to simulate the shell carbonate budget of an oyster reef. We identify five parameters descriptive of basic characteristics of the shell carbonate budget of a reef that limit simulation accuracy. Two describe the TAZ (taphonomically-active zone) and the distribution of shell carbonate within it. One is the taphonomic rate in the TAZ. Two determine the volume contribution of shell carbonate and the taphonomic loss rate within the reef framework. For Mid-Atlantic estuaries, model simulations suggest that reef accretion only occurs if oyster abundance is near carrying capacity. Simulations further suggest that reef accretion is infeasible …

Baroclinic Instability Of An Idealized Tidal Mixing Front, K. H. Brink

Journal of Marine Research

Tidal mixing fronts separate vertically homogenized waters from stratified ambient waters. The linear and nonlinear baroclinic stability of an idealized tidal mixing front is treated here in the parameter range that is stable with regard to symmetric instabilities and that has no bottom friction. All model configurations considered are unstable, and the dependence on bottom slope, stratification and other parameters is similar to that suggested by models (such as that of Blumsack and Gierasch, 1972) with much simpler configurations. The finite-amplitude evolution of the instabilities is treated using a primitive equation numerical model. The initial length scale and growth rate …

Hurricane Wake Restratification Rates Of One-, Two- And Three-Dimensional Processes, S. Haney, S. Bachman, B. Cooper, S. Kupper, K. Mccaffrey, L. Van Roekel, S. Stevenson, B. Fox-Kemper

Journal of Marine Research

The restratification of the cold wakes of Tropical Cyclones Fanapi, Frances, Igor and Katrina are examined based on derived scalings for processes that can restore the hurricane wake toward the precyclone conditions. The different restoration processes depend on the parameters of the wake: depth, width, buoyancy anomaly and wind stress. The parameters needed are derived for each wake from satellite and climatological data. The scalings are based on model results and existing parameterizations, including air-sea heat fluxes (one-dimensional) Ekman buoyancy fluxes (two-dimensional) and mixed layer eddies (three-dimensional). The dominant surface restoration occurs by a combination of surface fluxes and Ekman …

Modeling The Dispersal Of Eastern Oyster (Crassostrea Virginica) Larvae In Delaware Bay, Diego A. Narvaez, John M. Klinck, Eric N. Powell, Eileen E. Hofmann, John Wilkin, Dale B. Haidvogel

CCPO Publications

The interactions of circulation and growth processes in determining the horizontal distribution of eastern oyster (Crassostrea virginica) larvae in the Delaware Bay estuary were investigated with a coupled circulation-individual-based larvae model that used environmental conditions from the spawning seasons (mid-June to mid-September) of 1984, 1985, 1986, 2000, and 2001. Particles, representing oyster larvae, were released at five-day intervals from areas in Delaware Bay that correspond to natural oyster reefs. The simulated larval development time was used to estimate potential larval success, determined by the percent of larvae that successfully reached settlement size (330 µm) within the planktonic larval …

Circulation And Behavior Controls On Dispersal Of Eastern Oyster (Crassostrea Virginica) Larvae In Delaware Bay, Diego A. Narváez, John N. Klinck, Eric N. Powell, Eileen E. Hofmann, John Wilkin, Dale B. Haidvogel

Journal of Marine Research

The relative contributions of the spring-neap tides, river discharge and vertical behavior to the dispersal of eastern oyster (Crassostrea virginica) larvae in Delaware Bay is investigated with a coupled circulation-individual-based larvae model. The coupled model simulates larval growth and behavior along particle trajectories using temperature and salinity conditions obtained from an implementation of the Regional Ocean Model System (ROMS) for Delaware Bay. Particles, representing oyster larvae, are released at five-day intervals during the spawning seasons (mid-June to mid-September) of 1984, 1985, 1986, 2000 and 2001 from areas that correspond to natural oyster reefs in Delaware Bay. Successful larvae …

Optical Detection And Classification Of Phytoplankton Taxa Through Spectral Analysis, Daniel Tyler Sensi

USF Tampa Graduate Theses and Dissertations

Phytoplankton serve as the bottom of the marine food web and therefore play an essential role in marine ecosystems. On the other hand, coastal phytoplankton communities can adversely affect the marine ecosystem and humans. A variety of techniques have been developed to measure and study phytoplankton, including in situ methods (e.g., flow cytometry) and laboratory methods (e.g., microscopic taxonomy). These provide accurate measurements of phytoplankton taxa and concentrations, yet they are limited in space and time, and synoptic information is difficult to obtain with these techniques.

Optical remote sensing may provide complementary information for its synoptic nature, as demonstrated by …

Preliminary Evaluations Of Secondary Productivity Estimates As Indicators Of The Ecological Value Of The Benthos To Higher Trophic Levels In Chesapeake Bay, Daniel M. Dauer, Michael F. Lane, Roberto J. Llansó, Robert Diaz

Benthic Applications

The primary objective of this project was to develop an analytical tool that management could use to assess the ecological value of the benthos for higher trophic levels. Ideally any tool developed should be simple to implement, adaptable to both fixed and probability monitoring programs and applicable across multiple spatial and temporal scales. Direct evaluations of secondary productivity involve time-consuming cohort or size-based methods that require multiple measurements of the populations in question over time (Dolbeth et al., 2005; Cusson and Bourget, 2005). However, empirical regression models have been developed that provide reasonable alternatives to these techniques when direct measurements …

Quantification Of Nitrate Sources And Sinks Using A Water Quality Network In Morro Bay Estuary, California, Johanna Nadia Jean Weston

Master's Theses

Using an instrumented water quality network in Morro Bay Estuary, California from 2007 to 2010 (15 min sampling frequency), this study addressed the two objectives of constructing a nitrate budget and assessing the influence of sampling frequency on water quality parameters. These two objectives led to the submission of an original report of research (Appendix A) and a note (Appendix B) to peer-reviewed journals.

The first objective was to characterize the high spatial and temporal variation in physical parameters and nitrate concentrations and to construct a nitrate budget quantifying sources and sinks of nitrate from the ocean, streams, and groundwater, …

Composition Of Suspended And Benthic Particulate Matter In The Tidal Freshwater James River, Anne Schlegel

Theses and Dissertations

Investigating linkages between the compositions of suspended (seston) and benthic particulate matter is important to the understanding of organic matter (OM) cycling and nutrient retention in aquatic systems. We compared the quantity and quality of the truly suspended (TS) and settleable (SB) fractions of seston as well as benthic particulate matter in the tidal freshwater James River, Virginia. The mass of seston and OM was consistently higher in the TS fraction compared to the SB fraction. OM was preferentially retained in the TS fraction relative to seston. The proportional contribution of OM constituents (chlorophyll a, particulate organic carbon and nitrogen) …

Anthropogenic Impact On Meiofauna In Myrtle Beach Area Estuaries, Melissa Martinez

Honors Theses

The population of South Carolina has been steadily increasing for years, especially in coastal areas. In fact, Horry County, which contains Myrtle Beach, has shown a population increase of 37% in the last decade. With significant population increase comes a proportional increase in urbanization, defined by more industries, more buildings, and more natural areas encroached upon. Not only does urbanization physically impact the natural environment, there are also chemical impacts through the release of anthropogenic waste and chemicals. Through runoff and direct input, these chemicals can eventually reach the estuaries and may cause some changes in those communities. For this …

Secondary Instability Of Salt Sheets, Satoshi Kimura, William Smyth

Journal of Marine Research

In the presence of a vertically varying horizontal current (background shear), the salt-fingering instability is supplanted by the salt-sheet instability. Previous direct numerical simulation (DNS) experiments on salt sheets revealed that flow becomes turbulent via secondary instabilities. We call these instabilities zig-zag and tip modes. Here, we investigate the physics of these modes using linear normal mode stability analysis. As the primary instability (salt-sheet instability) grows, the zig-zag mode emerges, which denotes undulation of growing salt sheets at the center of fingering regions. This mode is shown to be an extension of secondary instability of unsheared two-dimensional salt-fingering. The zig-zag …

Spin-Up And Adjustment Of The Antarctic Circumpolar Current And Global Pycnocline, Lesley C. Allison, Helen L. Johnson, David P. Marshall

Journal of Marine Research

A theory is presented for the adjustment of the Antarctic Circumpolar Current (ACC) and global pycnocline to a sudden and sustained change in wind forcing. The adjustment timescale is controlled by the mesoscale eddy diffusivity across the ACC, the mean width of the ACC, the surface area of the ocean basins to the north, and deep water formation in the North Atlantic. In particular, northern sinking may have the potential to shorten the timescale and reduce its sensitivity to Southern Ocean eddies, but the relative importance of northern sinking and Southern Ocean eddies cannot be determined precisely, largely due to …

Dispersion And Connectivity Estimates Along The U.S. West Coast From A Realistic Numerical Model, Patrick T. Drake, Christopher A. Edwards, John A. Barth

Journal of Marine Research

Near-surface particle dispersion, larval dispersal and connectivity along the U.S west coast were explored using a realistic numerical model of the California Current System. Seasonal model velocities were qualitatively and quantitatively evaluated using Global Drifter Program data. The model displayed a clear seasonal cycle of eddy energy near the coast with energy maxima southwest of major headlands. Eddy speeds were correlated with drifter-based estimates during summer and fall when compared spatially. Over six million passive, Lagrangian particles were released in the upper 20 m of the water column within 10 km of the California and Oregon coasts and tracked for …

Transport And Retention Of The Mitten Crab (Eriocheir Sinensis) In A Mid-Atlantic Estuary: Predictions From A Larval Transport Model, Charles E. Tilburg, Ana I. Dittel, Douglas C. Miller, Charles E. Epifanio

Journal of Marine Research

Invasive species cause extensive ecological damage in freshwater and marine habitats and are a threat to biodiversity in aquatic ecosystems world-wide. One such species, the Chinese mitten crab, Eriocheir sinensis, has invasive populations in northern Europe and San Francisco Bay, and there are confirmed reports of breeding female crabs in both the Chesapeake and Delaware Bays. Despite their threat to these ecosystems, there are still large gaps in the current understanding of this species' larval biology that are critical to predicting the potential for large populations to establish in East Coast bays and estuaries. We addressed these issues by using …

Vladimir Kamenkovich – Scientist And Teacher, V. O. Ivchenko, G. M. Reznik

Journal of Marine Research

This special collection of articles is dedicated to Vladimir Kamenkovich, on the occasion of his 80th birthday. We take this opportunity to celebrate his extraordinary career in science and education. Through his pioneering work, Vladimir Kamenkovich has made important contributions to the development of modern physical oceanography, being, in the words of Peter Rhines, “a great force in ocean dynamics,” and he has inspired many scientists worldwide. It is fair to say that the field of ocean dynamics would have been very different if Vladimir had chosen a different career path.

The Two-Layer Skirted Island, Joseph Pedlosky, Roberto Iacono, Ernesto Napolitano, Michael A. Spall

Journal of Marine Research

The flow around a planetary scale island in a baroclinic ocean is examined when the island possesses a topographic skirt representing a steep continental slope and the ocean is modeled as a two-layer system in order to examine the role of stratification in the circulation. The study extends an earlier barotropic model of similar geometry and forcing to focus on the degree to which the topography, limited here to the lower of the two layers, affects the circulation and to what degree the circulation is shielded by stratification from the topographic effects noted in the simpler barotropic model. As in …

Numerical Simulations Of Dense Water Cascading On A Steep Slope, Fred Wobus, Georgy I. Shapiro, Miguel A. M. Maqueda, John M. Huthnance

Journal of Marine Research

The sinking of dense shelf waters down the continental slope (or "cascading") contributes to oceanic water mass formation and carbon cycling. Cascading over steep bottom topography is studied here in numerical experiments using POLCOMS, a 3-D ocean circulation model using a terrain-following s-coordinate system. The model setup is based on a laboratory experiment of a continuous dense water flow from a central source on a conical slope in a rotating tank. The governing parameters of the experiments are the density difference between plume and ambient water, the flow rate, the speed of rotation and (in the model) diffusivity and …