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Ocean Ecosystem Stewardship, W. M. Von Zharen

William & Mary Environmental Law and Policy Review

No abstract provided.

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

Faculty Publications

No abstract provided.

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Enhanced Dispersion Of Near-Inertial Waves In An Idealized Geostrophic Flow, N. J. Balmforth, Stefan G. Llewellyn Smith, W. R. Young

Journal of Marine Research

This paper presents a simplified model of the process through which a geostrophic flow enhances the vertical propagation of near-inertial activity from the mixed layer into the deeper ocean. The geostrophic flow is idealized as steady and barotropic with a sinusoidal dependence on the north-south coordinate; the corresponding streamfunction takes the form ψ = - Ψ cos (2αy). Near-inertial oscillations are considered in linear theory and disturbances are decomposed into horizontal and vertical normal modes. For this particular flow, the horizontal modes are given in terms of Mathieu functions. The initial-value problem can then be solved by projecting …

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The Malin Cascade In Winter 1996, A. E. Hill, A. J. Souza, K. Jones, J. H. Simpson, G. I. Shapiro, R. Mccandliss, H. Wilson, J. Leftley

Journal of Marine Research

We report evidence for cascading of shelf-edge water down the continental slope northwest of Ireland at 55N in February 1996. The measured surface density contrast between shelf-edge and slope waters was 0.01 kg m^-3 and the resulting dense plume was 20-50 m thick over the continental slope and penetrated to a depth of 500 m. Cascade waters were warmer but saltier than overlying slope waters and their shelf-edge origin was confirmed by relatively higher chlorophyll concentrations and a distinctive nutrient signature. Other cross-slope transects 100 km north and south of the cascade site showed dense water at the shelf …

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The Influence Of The Ambient Flow On The Spreading Of Convected Water Masses, Sonya Legg, John Marshall

Journal of Marine Research

We investigate the influence of a cyclonic vortical flow on the lateral spreading of newly mixed fluid generated through localized deep convection. Localized open ocean deep convection often occurs within such a cyclonic gyre circulation, since the associated upwardly domed isopycnals and weaker stratification locally precondition the ocean for deeper convection. In the absence of ambient flow, localized convection has been shown to result in strong lateral fluxes of buoyancy generated by baroclinic instability, sufficient to offset the local surface buoyancy loss and limit the density anomaly of the convectively generated water mass. Here we examine the consequences of a …

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The Southern Flux Of Sea Ice In The Tatarskiy Strait, Japan Sea And The Generation Of The Liman Current, Seelye Martin, Mitsuhiro Kawase

Journal of Marine Research

The circulation in the surface waters of the Japan Sea is driven in part by thermohaline forcing associated with the flux of cold, low-salinity water from the Tatarskiy Strait. Existing numerical models suggest that this water contributes to the Liman Current, which flows from northeast to southwest along the Russian coast. The major source of Japan Sea freshwater is the Amur River, which flows into the sea through Tatarskiy Strait, but has a near-zero minimum during January to March. As an alternate source of freshwater to the surface layer, we derive from meteorological and remote sensing data for the 1992-1994 …

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Corrigendum To Surface-Intensified Rossby Waves Over Rough Topography (J. Mar. Res., 50, 367–384), R. M. Samelson

Journal of Marine Research

In Samelson (1992), Eq. (13) should be changed to… respectively. The same error appears in the Abstract.

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Tidal Resuspension And Deposition Of Particulate Matter In The Oyster Grounds, North Sea, Wim Van Raaphorst, Hans Malschaert, Hans Van Haren

Journal of Marine Research

Moored current meters, fluorom eters and transmissometers were used in combination with sediment traps (aspect ratio >4) and shipborne sampling to determine fluxes of deposition and resuspension of total suspended matter (TSM) under tidal action in the 45 m deep Oyster Grounds, North Sea. Here, we present data from the mixed layer below the major thermocline at about 20 m above the bottom (mab) as obtained during a 14-day period of calm weather in July 1994. Around neap tide near-bottom current velocities remained smaller than 0.15 m s^-1 and TSM was dominated by particles advected from a relatively turbid …

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Under-Ice Observations Of Water Column Temperature, Salinity And Spring Phytoplankton Dynamics: Eastern Bering Sea Shelf, P. J. Stabeno, J. D. Schumacher, R. F. Davis, J. M. Napp

Journal of Marine Research

The inundation of two moored platforms by sea ice in late winter and early spring of 1995 provided unique time series of water column temperature, salinity, estimated chlorophyll-a, and phytoplankton fluorescence under advancing and retreating sea ice. One platform was located at 72 m in the weakly advective middle shelf regime. Here, chlorophyll-a concentrations began increasing shortly after the arrival of the ice (arch) during the period of weak stratification and continued to increase while wind actively mixed the water column to >60 m. Changes in water column structure and properties resulted from an event of strong …

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Deep Water Properties, Velocities, And Dynamics Over Ocean Trenches, Gregory C. Johnson

Journal of Marine Research

Observations of water properties and deep currents over several trenches in the Pacific Ocean central basins give consistent evidence for recent ventilation of water below the trench sills and cyclonic sense of circulation over the trenches. A dynamical argument for this pattern is advanced. First, a review of previous analyses of hydrographic data shows that the trenches are well ventilated by dense bottom water, that within the trenches this bottom water generally spreads away from its source, and that a cyclonic sense of circulation is suggested over some trenches. Then, this cyclonic sense of circulation over the trenches is further …

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A Numerical Study Of Layer Formation Due To Fingers In Double-Diffusive Convection In A Vertically-Bounded Domain, Tamay M. Özgökmen, Oleg E. Esenkov, Donald B. Olson

Journal of Marine Research

The evolution of fingers in a double-diffusive system is investigated using numerical integration of two-dimensional equations of motion for an incompressible, Boussinesq fluid. The computational domain is periodic in the horizontal direction and is closed with no-flux boundary conditions in the vertical direction. The main result of this study is the evolution of the system from initially linear profiles for both fast and slow diffusing components to a layered state characterized by a finger zone sandwiched between two mixed layers. The horizontal boundaries in this system play an important role in the development of the layered state. At the top …

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The Rectification Of Wind-Driven Flow Due To Its Instabilities, Caroline A. Katsman, Henk A. Dijkstra, Sybren S. Drijfhout

Journal of Marine Research

Within a quasi-geostrophic two-layer model of the wind-driven ocean circulation, an idealized symmetric double gyre flow is considered. When lateral friction is large enough, this flow is steady and characterized by a motionless lower layer. As friction is decreased, the flow undergoes a transition to time-dependence through a Hopf bifurcation, associated with a mixed barotropic/baroclinic instability. It is shown that the nonlinear self-interaction of this oscillatory unstable mode induces a nonzero time mean response in the lower layer. The origin of this deep flow is clarified through a weakly nonlinear analysis near critical conditions. It is explained how the perturbation …

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Process-Specific Cues For Recruitment In Sedimentary Environments: Geochemical Signals?, Sarah A. Woodin, Roberta L. Marinelli, Sara M. Lindsay

Journal of Marine Research

The most biologically and geochemically active marine sediments are characterized by steep chemical gradients within the top centimeters of sediment (Berner, 1980). A common feature of these environments is disruptions of surface sediments by both physical and biotic forces. Growth and mortality rates for new recruits are affected by many of these surface perturbations. At the same time, these disturbances also impose a discontinuity in concentration across the sediment-water interface, and accordingly, a change in surface chemistry. In this paper we present evidence that the cue used by juveniles to distinguish between recently disturbed and undisturbed surfaces may be disruption …

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Seabed Drag Coefficient Over Natural Beds Of Horse Mussels (Atrina Zelandica), Malcolm O. Green, Judi E. Hewitt, Simon F. Thrush

Journal of Marine Research

Measurements of seabed drag coefficient, C₁₀₀, were made under tidal currents at four sites in Mahurangi Harbour, New Zealand. At the first three sites the dominant roughness element was the pinnid bivalve, Atrina zelandica (horse mussel). At the fourth site, which was devoid of horse mussels but covered in cockle shells, patches of seaweed and crab burrows, C₁₀₀ was smallest (0.0055), but still twice as large as the value typically applied to abiotic, flat, cohesionless seabeds (0.0025). The mean drag coefficient plus-or-minus standard error at the three sites with horse mussels was: 0.0082 ± 0.0010 (site 1); …

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Three-Dimensional Stirring Of Thermohaline Fronts, Patrice Klein, Anne-Marie Treguier, Bach Lien Hua

Journal of Marine Research

This study investigates the stirring of the thermohaline anomalies in a fully turbulent quasigeostrophic stratified flow. Temperature and salinity fields are permanently forced at large scales and are related to density by a linear equation of state. We show, using some inherent properties of quasi-geostrophic turbulence, that the 3-D ageostrophic circulation is the key dynamical characteristic that governs the strength and the spatial distribution of small-scale thermohaline fronts that are strongly density compensated. The numerical simulations well illustrate the formation by the mesoscale eddy field of sharp thermohaline fronts that are mainly located in the saddle regions and around the …

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Temporal Variability And Composition Of Settling Particle Fluxes On The Barcelona Continental Margin (Northwestern Mediterranean), P. Puig, A. Palanques

Journal of Marine Research

The results of a year-long sediment-trap experiment provide the first direct observations of sediment fluxes to the seafloor on the Barcelona continental margin. Time-series of vertical particle fluxes and major constituents (organic carbon, biogenic silica, calcium carbonate and aluminosilicates) were determined inside and in the vicinity of the Foix submarine canyon from May 1993 to April 1994. The spatial and temporal variability of bi-weekly total mass fluxes indicate significant high frequency variability related to physical and biological processes at this site. The Foix submarine canyon acts as an actual conduit for transport of sediment from the shelf to the slope, …

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Excretion Of Trace Elements By Marine Copepods And Their Bioavailability To Diatoms, Wen-Xiong Wang, Nicholas S. Fisher

Journal of Marine Research

We measured the physiological turnover rate (= excretion rate) of five trace elements (Ag, Cd, Co, Se and Zn) in the marine copepod Temora longicornis following feeding on radiolabeled diatoms. The turnover rate constants of trace elements in copepods were high (0.05 to 0.38 d^-1) and were comparable to published values for N and P excretion. Ag, Cd and Co were excreted at higher rates than Se and Zn. Turnover rate constants of Ag, Cd, and Co also increased with increasing food concentration, whereas excretion of Se and Zn was not affected by food concentration. There was little …

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The Non-Wavelike Response Of A Continental Shelf To Wind, G. T. Csanady

Journal of Marine Research

An overlooked aspect of continental shelf wave generation by wind is that a non-wavelike flow field may accompany the waves. To explore this possibility, we calculate the response of an inclined plane shelf to suddenly applied alongshore wind, affecting a finite portion of the coast. The calculations are based on the classical theory of continental shelf waves, supposing low frequency motions and invoking the boundary layer approximation (alongshore scales much longer than cross-shore ones). The results reveal non-wavelike circulations, with or without bottom friction, on a shelf of finite or unlimited width, unaffected by changing offshore boundary conditions. In the …

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Nonlinear Limits To Ocean Thermal Structure, N. P. Fofonoff

Journal of Marine Research

The nonlinear volume changes associated with diffusion and mixing of different seawater types produce significant conversions of gravitational potential energy to kinetic energy to maintain and enhance mixing processes and to limit the magnitudes of temperature gradients that can persist in the ocean. Several examples are given to illustrate these critical temperature gradients beyond which conversion exceeds local energy consumption by mixing. The vertical temperature gradients in the Gulf Stream reduce downstream from Cape Hatteras to the critical limit found in the North Atlantic thermocline. The limiting gradients are also seen in surface thermoclines and in "staircase" structures. Although the …

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Linear Ocean Circulation Theory With Realistic Bathymetry, Rick Salmon

Journal of Marine Research

The linear equations governing stratified, wind-driven flow in an ocean of arbitrary shape may be combined into a single "advection-diffusion" equation for the pressure , in which the "flow" advecting  includes a delta-function contribution at the ocean bottom in the sense of southward "advection" of  along western continental slopes. This interpretation of the -equation helps to explain numerical solutions obtained with a finite-element model incorporating realistic North Atlantic bathymetry.

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On The Stability Of The Wind-Driven Circulation, P. Berloff, S. P. Meacham

Journal of Marine Research

This work examines the instabilities of steady circulations driven by stationary single-gyre wind forcing in closed rectangular basins with different aspect ratios. The stratified ocean is modeled with quasi-geostrophic 1.5-layer (equivalent-barotropic) and two-layer models. As friction is reduced, a stability threshold is encountered. In the vicinity of this threshold, unstable steady states and their unstable eigenmodes are determined. The structures of the eigenmodes and their associated energy conversion terms allow us to characterize the instabilities. In each case, the loss of stability is associated with an oscillatory instability. Several different instability mechanisms are observed. Which of these is responsible for …

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Observations Of Temporal Changes Of Tritium-3he Age In The Eastern North Atlantic Thermocline: Evidence For Changes In Ventilation, Paul E. Robbins, William J. Jenkins

Journal of Marine Research

A compilation of fifteen years of tritium and 3He measurements is used to examine the ventilation of the eastern North Atlantic subtropical gyre with specific emphasis on the temporal character of the tracer age field. A multivariate regression analysis in the form of a spatiotemporal Taylor expansion is applied to observations interpolated onto isopycnal surfaces. The time-dependent component of the tracer age field is found to be statistically significant, explaining approximately 10% of the variance of the tracer age observations in the upper thermocline (σ_ = 26.5) and increasing to roughly 50% of the variance in the lower thermocline …

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Tidal Mixing And Cross-Frontal Particle Exchange Over A Finite Amplitude Asymmetric Bank: A Model Study With Application To Georges Bank, Changsheng Chen, Robert C. Beardsley

Journal of Marine Research

Tidal mixing, internal wave bores, and cross-bank particle transport over a finite amplitude asymmetric bank are examined using a two-dimensional primitive equation ocean model with Mellor and Yamada (level 2.5) turbulent closure. Driven by the surface M₂ tide, the model results show that tidal mixing exhibits temporal and spatial asymmetries on southern and northern flanks of the bank. It is strongest near the bottom around maximum on-bank tidal flow as a result of gravitational instability when denser water is advected upslope over lighter water. A sharp thermal depression occurs on the steep northern flank, which produces large current shear …

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Small Viscosity Behavior Of A Homogeneous, Quasi-Geostrophic, Ocean Circulation Mode, Robert B. Scott, David N. Straub

Journal of Marine Research

Insensitivity to turbulent closure in the wind-driven nonlinear Stommel-Munk model is addressed theoretically and numerically. The QG energy equation is used to show that, with the assumption that the maximum velocities occur at inertial length scales or smaller, a Sverdrup interior is consistent with the small Rossby number assumption only when the frictional parameters exceed critical values. For frictional parameters smaller than these values, valid solutions must decrease the energy source. This is possible for non-Sverdrup solutions since the energy source is dependent on the solution. The steady-state behavior of the model was investigated via a pseudo-arclength continuation algorithm. Dependence …

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Larval Settlement In Turbulent Pipe Flows, James E. Eckman, David O. Duggins

Journal of Marine Research

In two experiments, larval settlement was studied within a series of pipes, each containing steady, turbulent, flowing seawater. The study was designed to determine effects of flow (speed, turbulence intensity and wall shear stress) and surface orientation on rates of settlement of larvae of various taxa, and to relate variability in patterns of settlement among orientations and flows to the concomitant variability expected in rates of larval supply or delivery to the pipe walls. Patterns of settlement of all five taxa (the barnacle Balanus spp., the mussel Mytilus trossulus, the serpulid polychaete Pseudochitinopoma occidentalis, the cyclostome bryozoan Tubulipora sp., …

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A Streamtube Model Of Rotating Turbidity Currents, P. W. Emms

Journal of Marine Research

A rotating turbidity current is modeled as a steady tube of sediment-laden water traversing along and down a uniform slope representing the continental shelf. The model includes parameterizations of erosion of sediment from the seabed into the plume, deposition onto the seafloor, bottom friction, and turbulent entrainment of the overlying ambient seawater. The purpose of the work is to study how these parameterizations affect the path the current takes on the slope and to determine criteria which affect the qualitative behavior of the model solutions. It is found that there are three possible final states to the model. The first …

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The Salt Finger Amplitude In Unbounded T-S Gradient Layers, Melvin E. Stern, Timour Radko

Journal of Marine Research

Finite amplitude numerical calculations are made for a completely unbounded salt finger domain whose overall vertical "property" gradients (T_z and S_z) are uniform and remain unaltered in time. For diffusivity ratio τ = κ_S/κ_T = O (1), Prandtl number ν/κ_T >> 1, and density ratio R = T_z/S_z > 1 this regime corresponds to a "double gradient" sugar (S)—salt (T) experiment. Two-dimensional pseudo-spectral calculations are made in the vicinity of the minimum critical condition for salt finger instability, viz., small ε ≡ (Rτ)^{-1 …}

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Simulation Of Primary Production And Export Fluxes In The Northwestern Mediterranean Sea, Marina Lévy, Laurent Mémery, Jean-Michel André

Journal of Marine Research

A biogeochemical model, BIOMELL (BIOgeochemical Model of the Euphotic Layer of Lodyc), has been developed to simulate the temporal evolution of the main nitrogen stocks and fluxes at the DyFAMed station (Dynamique des Flux Atmospheriques en Mediterranée), located in the Northwestern Mediterranean Sea. This mainly oligotrophic region is characterized by a strong seasonal cycle, and a significant export of dissolved organic matter compared to the particulate export measured by sediment traps. Validation of the model is made using temperature, nitrate and chlorophyll profiles acquired at DyFAMed approximately every month in 1991. Extended datasets from specific years are also used to …

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On The Parameterization Of Eddy Transfer, Part Ii: Tests With A Channel Model, Peter D. Killworth

Journal of Marine Research

In Part I of this paper (Killworth, 1997), a new eddy parameterization scheme was presented. Here, the scheme is tested by comparing its predictions with those of multi-year averages from an eddy-resolving channel model. Its accuracy is similar to that of a tuned version of previous schemes. However, a tuned version of the new parameterization can reproduce both the long-term average of the eddy-resolving solution as well as the initial slumping of a narrow front. Both tuned schemes reproduced the bolus transport well. The new parameterization reproduces the observed feature that the diffusivity is maximal at mid-depth and minimal at …

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Does The Sverdrup Critical Depth Model Explain Bloom Dynamics In Estuaries?, Lisa V. Lucas, James E. Cloern, Jeffrey R. Koseff, Stephen G. Monismith, Janet K. Thompson

Journal of Marine Research

In this paper we use numerical models of coupled biological-hydrodynamic processes to search for general principles of bloom regulation in estuarine waters. We address three questions: What are the dynamics of stratification in coastal systems as influenced by variable freshwater input and tidal stirring? How does phytoplankton growth respond to these dynamics? Can the classical Sverdrup Critical Depth Model (SCDM) be used to predict the timing of bloom events in shallow coastal domains such as estuaries? We present results of simulation experiments which assume that vertical transport and net phytoplankton growth rates are horizontally homogeneous. In the present approach the …

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Full-Text Articles in Entire DC Network

Ocean Ecosystem Stewardship, W. M. Von Zharen

William & Mary Environmental Law and Policy Review

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

Faculty Publications

Enhanced Dispersion Of Near-Inertial Waves In An Idealized Geostrophic Flow, N. J. Balmforth, Stefan G. Llewellyn Smith, W. R. Young

Journal of Marine Research

The Malin Cascade In Winter 1996, A. E. Hill, A. J. Souza, K. Jones, J. H. Simpson, G. I. Shapiro, R. Mccandliss, H. Wilson, J. Leftley

Journal of Marine Research

The Influence Of The Ambient Flow On The Spreading Of Convected Water Masses, Sonya Legg, John Marshall

Journal of Marine Research

The Southern Flux Of Sea Ice In The Tatarskiy Strait, Japan Sea And The Generation Of The Liman Current, Seelye Martin, Mitsuhiro Kawase

Journal of Marine Research

Corrigendum To Surface-Intensified Rossby Waves Over Rough Topography (J. Mar. Res., 50, 367–384), R. M. Samelson

Journal of Marine Research

Tidal Resuspension And Deposition Of Particulate Matter In The Oyster Grounds, North Sea, Wim Van Raaphorst, Hans Malschaert, Hans Van Haren

Journal of Marine Research

Under-Ice Observations Of Water Column Temperature, Salinity And Spring Phytoplankton Dynamics: Eastern Bering Sea Shelf, P. J. Stabeno, J. D. Schumacher, R. F. Davis, J. M. Napp

Journal of Marine Research

Deep Water Properties, Velocities, And Dynamics Over Ocean Trenches, Gregory C. Johnson

Journal of Marine Research

A Numerical Study Of Layer Formation Due To Fingers In Double-Diffusive Convection In A Vertically-Bounded Domain, Tamay M. Özgökmen, Oleg E. Esenkov, Donald B. Olson

Journal of Marine Research

The Rectification Of Wind-Driven Flow Due To Its Instabilities, Caroline A. Katsman, Henk A. Dijkstra, Sybren S. Drijfhout

Journal of Marine Research

Process-Specific Cues For Recruitment In Sedimentary Environments: Geochemical Signals?, Sarah A. Woodin, Roberta L. Marinelli, Sara M. Lindsay

Journal of Marine Research

Seabed Drag Coefficient Over Natural Beds Of Horse Mussels (Atrina Zelandica), Malcolm O. Green, Judi E. Hewitt, Simon F. Thrush

Journal of Marine Research

Three-Dimensional Stirring Of Thermohaline Fronts, Patrice Klein, Anne-Marie Treguier, Bach Lien Hua

Journal of Marine Research

Temporal Variability And Composition Of Settling Particle Fluxes On The Barcelona Continental Margin (Northwestern Mediterranean), P. Puig, A. Palanques

Journal of Marine Research

Excretion Of Trace Elements By Marine Copepods And Their Bioavailability To Diatoms, Wen-Xiong Wang, Nicholas S. Fisher

Journal of Marine Research

The Non-Wavelike Response Of A Continental Shelf To Wind, G. T. Csanady

Journal of Marine Research

Nonlinear Limits To Ocean Thermal Structure, N. P. Fofonoff

Journal of Marine Research

Linear Ocean Circulation Theory With Realistic Bathymetry, Rick Salmon

Journal of Marine Research

On The Stability Of The Wind-Driven Circulation, P. Berloff, S. P. Meacham

Journal of Marine Research

Observations Of Temporal Changes Of Tritium-3he Age In The Eastern North Atlantic Thermocline: Evidence For Changes In Ventilation, Paul E. Robbins, William J. Jenkins

Journal of Marine Research

Tidal Mixing And Cross-Frontal Particle Exchange Over A Finite Amplitude Asymmetric Bank: A Model Study With Application To Georges Bank, Changsheng Chen, Robert C. Beardsley

Journal of Marine Research

Small Viscosity Behavior Of A Homogeneous, Quasi-Geostrophic, Ocean Circulation Mode, Robert B. Scott, David N. Straub

Journal of Marine Research

Larval Settlement In Turbulent Pipe Flows, James E. Eckman, David O. Duggins

Journal of Marine Research

A Streamtube Model Of Rotating Turbidity Currents, P. W. Emms

Journal of Marine Research

The Salt Finger Amplitude In Unbounded T-S Gradient Layers, Melvin E. Stern, Timour Radko

Journal of Marine Research

Simulation Of Primary Production And Export Fluxes In The Northwestern Mediterranean Sea, Marina Lévy, Laurent Mémery, Jean-Michel André

Journal of Marine Research

On The Parameterization Of Eddy Transfer, Part Ii: Tests With A Channel Model, Peter D. Killworth

Journal of Marine Research

Does The Sverdrup Critical Depth Model Explain Bloom Dynamics In Estuaries?, Lisa V. Lucas, James E. Cloern, Jeffrey R. Koseff, Stephen G. Monismith, Janet K. Thompson

Journal of Marine Research