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Analysis Of The Barotropic Model Of The Subtropical Gyre In The Ocean For Finite Reynolds Numbers. Part I, V. M. Kamenkovich, V. A. Sheremet, A. R. Pastushkov, S. O. Belotserkovsky Jan 1995

Analysis Of The Barotropic Model Of The Subtropical Gyre In The Ocean For Finite Reynolds Numbers. Part I, V. M. Kamenkovich, V. A. Sheremet, A. R. Pastushkov, S. O. Belotserkovsky

Journal of Marine Research

A barotropic time-dependent model of the wind-driven currents in the subtropical region of the ocean was considered taking both nonlinearity and lateral friction into account. The boundary conditions are the impermeability at all boundaries, no-slip at the coasts and slip at the fluid boundaries. It is shown that the solution of the problem is characterized by two nondimensional parameters ε (the ratio of width of the inertial boundary layer to a basin dimension) and R (Reynolds number for the boundary layer). A series of numerical experiments is discussed with fixed ε = 0.01 and varying R to analyze the joint …

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A Decadal Oscillation Due To The Coupling Between An Ocean Circulation Model And A Thermodynamic Sea-Ice Model, Sheng Zhang, Charles A. Lin, Richard J. Greatbatch Jan 1995

A Decadal Oscillation Due To The Coupling Between An Ocean Circulation Model And A Thermodynamic Sea-Ice Model, Sheng Zhang, Charles A. Lin, Richard J. Greatbatch

Journal of Marine Research

3-dimensional, planetary-geostrophic, ocean general circulation model is coupled to a thermodynamic sea-ice model. The thermal coupling takes account of the insulating effect of the ice. A simple approach is taken in the case of the freshwater flux by allowing this to pass through the ice, except that some is used for snow accumulation. It is then modified by salinity rejection/dilution due to freezing/melting. The model has idealized box geometry extending 60° in both latitude and longitude, with a horizontal resolution of 2° and 14 vertical levels. Annual mean surface forcings are used. The coupled system is first spun up using …

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Mesoscale Distribution Of Zooplankton In The California Current In Late Spring, Observed By Optical Plankton Counter, Mark E. Huntley, Meng Zhou, Walter Nordhausen Jan 1995

Mesoscale Distribution Of Zooplankton In The California Current In Late Spring, Observed By Optical Plankton Counter, Mark E. Huntley, Meng Zhou, Walter Nordhausen

Journal of Marine Research

A survey of zooplankton in the upper 300 m of the central California Current, from the coastal shelf to 128W and between 36.5N and 39.5N, was conducted in early June 1993 using an Optical Plankton Counter (OPC) as part of an interdisciplinary study of mesoscale ocean circulation and biological dynamics. The OPC was part of a multi-instrument package towed on an undulating vehicle (SeaSoar). Estimates of normalized size spectra and absolute abundance from OPC data compared favorably with measurements based on Bongo net catches. After processing, the standardized OPC data set provides a resolution of ≈7 km in the horizontal …

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Isopycnal Mixing And The Veronis Effect In An Ocean General Circulation Model, William A. Gough, Charles A. Lin Jan 1995

Isopycnal Mixing And The Veronis Effect In An Ocean General Circulation Model, William A. Gough, Charles A. Lin

Journal of Marine Research

In this study we have run a number of numerical simulations to examine the ‘Veronis effect’ in an ocean general circulation model. This effect is characterized by anomalous interior downwelling, east of the western boundary current of an ocean basin. The impact of varying the horizontal diffusivity and the use of an isopycnal mixing parameterization are examined. Several diagnostics are used. The net volume transport for a sector in the southern part of the domain, east of the western boundary is found to be the clearest indicator of the strength of the Veronis effect. This effect is found to depend …

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Fe, Zn, Mn And N Transfer Between Size Classes In A Coastal Phytoplankton Community: Trace Metal And Major Nutrient Recycling Compared, D. A. Hutchins, K. W. Bruland Jan 1995

Fe, Zn, Mn And N Transfer Between Size Classes In A Coastal Phytoplankton Community: Trace Metal And Major Nutrient Recycling Compared, D. A. Hutchins, K. W. Bruland

Journal of Marine Research

Experiments were performed to investigate transfer of 59Fe, 65Zn, 54Mn, and 15N from labeled cyanobacteria to the large (>8 μm or >5 μm) phytoplankton size class from Monterey Bay, California. Transfer of metal isotope activity was measured from and into total (for all isotopes) and intracellular (59Fe only) pools. Results demonstrated rapid and efficient transfer of nitrogen to the large phytoplankton size class; intracellular 59Fe was transferred into the intracellular and total pools of the >8 μm phytoplankton size class 70% and 130% as efficiently as nitrogen, respectively. 65Zn and 54 …

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Eddy Statistics In The South Atlantic As Derived From Drifters Drogued At 100, H. Schäfer, W. Krauss Jan 1995

Eddy Statistics In The South Atlantic As Derived From Drifters Drogued At 100, H. Schäfer, W. Krauss

Journal of Marine Research

More than 130 satellite-tracked buoys drogued at 100 m depth have been deployed by us in the South Atlantic during the years 1990–1993 in an ongoing program. After eliminating those portions of the trajectories for which the drogue was off, Lagrangian eddy statistics are computed and compared to the results of a similar data set in the North Atlantic and to previous results for the South Atlantic. Regarding the relations based on Taylor's theory, no significant differences can be seen between the North and South Atlantic. The Lagrangian integral time scale is inversely proportional to the r.m.s.-velocity which implies that …

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Analysis Of The Barotropic Model Of The Subtropical Gyre In The Ocean For Finite Reynolds Numbers. Part Ii., V. A. Sheremet, V. M. Kamenkovich, A. R. Pastushkov Jan 1995

Analysis Of The Barotropic Model Of The Subtropical Gyre In The Ocean For Finite Reynolds Numbers. Part Ii., V. A. Sheremet, V. M. Kamenkovich, A. R. Pastushkov

Journal of Marine Research

This paper is a continuation of Part I of the suggested study of the barotropic model of the subtropical gyre for finite Reynolds numbers. The statement of the problem, the motivation of the analysis, and the description of the general properties of the solution are presented in Part I (Kamenkovich et al., 1995). Here, in Part II of the study, the detailed investigations of the peculiarities of the solution are offered. The most striking feature of the solution is the formation of a recirculation gyre in the northwest corner of the basin. To study the gyre structure for various …

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On Geostrophic Adjustment Of A Two-Layer, Uniformly Rotating Fluid In The Presence Of A Step Escarpment, A. J. Willmott, E. R. Johnson Jan 1995

On Geostrophic Adjustment Of A Two-Layer, Uniformly Rotating Fluid In The Presence Of A Step Escarpment, A. J. Willmott, E. R. Johnson

Journal of Marine Research

This paper addresses the Rossby adjustment problem for an inviscid uniformly rotating two-layer fluid in the presence of a step escarpment of infinite length. The problem can be solved analytically for the case when the ratio of the step height to the average depth of the lower layer is small. In this case two well-separated adjustment time scales emerge; the rapid, inertial and the slow, topographic vortex-stretching time scales. The fluid is assumed to be at rest initially with imposed step discontinuities in the free surface and interfacial displacements oriented perpendicular to the escarpment. A two time-scale approach shows that …

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A Technique For The Determination Of Surface Heat And Freshwater Fluxes From Hydrographic Observations, Using An Approximate Adjoint Ocean Circulation Model, Andreas Schiller, Jürgen Willebrand Jan 1995

A Technique For The Determination Of Surface Heat And Freshwater Fluxes From Hydrographic Observations, Using An Approximate Adjoint Ocean Circulation Model, Andreas Schiller, Jürgen Willebrand

Journal of Marine Research

A technique to determine the large-scale time-averaged ocean circulation from hydrographic observations and surface flux estimates is described. It is based on an inversion of the Bryan-Cox ocean general circulation model. We have constructed an approximate adjoint to that model which is computationally simpler and more economic than the exact adjoint. The optimization algorithm, although not optimal in a statistical sense, allows calculation of all state variables such that they are consistent with the equilibrium dynamics of the circulation model and agree as closely as possible with the observed data. To verify the technique, we have performed identical twin experiments …

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Decay Of Plant Detritus In Organic-Poor Marine Sediment: Production Rates And Stoichiometry Of Dissolved C And N Compounds, Erik Kristensen, Kim Hansen Jan 1995

Decay Of Plant Detritus In Organic-Poor Marine Sediment: Production Rates And Stoichiometry Of Dissolved C And N Compounds, Erik Kristensen, Kim Hansen

Journal of Marine Research

Initial rates (30–60 days) and C:N stoichiometry of decomposition were examined in an organic-poor sediment (0.5% LOI) amended with fresh and dried yeast (Y) and Ruppia maritima (R) detritus by the use of “open system” core incubations and “closed system” jar incubations. High organic additions (0.5% dw) inhibited anaerobic carbon mineralization (i.e. sulfate reduction) and stimulated DOC production and nitrogen mineralization 3(R) to 15(Y) times (i.e. hydrolysis and fermentation). This indicated that carbon and nitrogen mineralization in the highly amended anaerobic sediments were uncoupled. Low organic additions (0.08% dw), on the other …

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Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner Nov 1994

Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner

Faculty Publications

Rates of benthic denitrification, oxygen consumption and nutrient regeneration were measured during winter, spring and summer in Galveston Bay (Texas, USA) sediments. Denitrification ranged from 0 to 47 µmol N2 m-2 h-1 with maximal rates generally occurring in the summer and the upper estuary. Oxygen consumption rates ranged from 38 µmol O2 m-2 h-1 in the winter to 353 µmol O2 m-2 h-1 in the summer and were correlated with denitrification rates. Variations in bay water temperature accounted for 52 % of the variability associated with denitrification rates whereas only 28% …

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Circulation, Fall 1994, Center For Coastal Physical Oceanography, Old Dominion University Oct 1994

Circulation, Fall 1994, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Fall 1994 issue of CCPO Circulation featuring article "Modeling Circulation and Larval Transport in the Chesapeake Bay"

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Emergence Of Fofonoff States In Inviscid And Viscous Ocean Circulation Models, Jian Wang, Geoffrey K. Vallis Jan 1994

Emergence Of Fofonoff States In Inviscid And Viscous Ocean Circulation Models, Jian Wang, Geoffrey K. Vallis

Journal of Marine Research

Numerical experiments are performed to directly test the emergence of the Fofonoff solution in an inviscid closed barotropic domain, and to explore its significance to the weakly dissipative system. The Fofonoff solution, characterized by a linear relationship between absolute vorticity and streamfunction, is generally realized as the time mean state of inviscid simulations over a fairly broad parameter range of varying (β-plane) Rossby number and resolution, in different geometrical domains, and with and without topography. The relevance of the Fofonoff solution to the viscous, decaying system is examined by numerical experiments with two different forms of viscosity, namely, biharmonic and …

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Effects Of Finite Scales Of Turbulence On Dispersion Estimates, Enrico Zambianchi, Annalisa Griffa Jan 1994

Effects Of Finite Scales Of Turbulence On Dispersion Estimates, Enrico Zambianchi, Annalisa Griffa

Journal of Marine Research

The eddy-diffusion parameterization of turbulent transport is based on the assumption, often questionable for geophysical flows, of infinitesimal scales of turbulence. In this paper we quantitatively compute what are the consequences of this assumption on the estimates of dispersion for some simple flows with oceanographical scales. We compare the analytical results of two different models, one with infinitesimal turbulent time scale (corresponding to a model with eddy-diffusion) and the other with finite scale T. The difference between the two model results normalized with respect to the estimate of the eddy-diffusion model, called Δ, is computed and it is used …

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Bottom Water Variability In The Samoa Passage, Gregory C. Johnson, Daniel L. Rudnick, Bruce A. Taft Jan 1994

Bottom Water Variability In The Samoa Passage, Gregory C. Johnson, Daniel L. Rudnick, Bruce A. Taft

Journal of Marine Research

The Samoa Passage (near 10S, 170W) is the channel through which the coldest, saltiest, densest bottom water approaches the North Pacific Ocean from its southern source. Over the past 25 years, three hydrographic sections have been made across the passage. A section occupied in 1968 shows little sign of modified North Atlantic Deep Water (NADW) within the northward flowing Lower Circumpolar Water (LCPW). In contrast, a section occupied in 1987 shows a strong negative curvature in -S (potential temperature-salinity) and a local maximum in salinity characteristic of NADW. A third section occupied in 1992 reveals a marginal NADW signature. …

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Modelling The Effect Of Physical Variability On The Midwater Chlorophyll Maximum, Jonathan Sharples, Paul Tett Jan 1994

Modelling The Effect Of Physical Variability On The Midwater Chlorophyll Maximum, Jonathan Sharples, Paul Tett

Journal of Marine Research

A coupled model, employing turbulence closure physics and cell-quota threshold limitation biology, has been used to simulate the evolution of the vertical distribution of phytoplankton in a seasonally stratified shelf sea. Predictions are compared with observations from the North Sea. Variations in surface wind stress, which episodically weaken the thermocline barrier to nutrient input to the photic zone, are shown to make an important contribution to the formation of a midwater chlorophyll maximum in Summer.

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The Sedimentary Mn Cycle In Long Island Sound: Its Role As Intermediate Oxidant And The Influence Of Bioturbation, O2,And Corg Flux On Diagenetic Reaction Balances, Robert C. Aller Jan 1994

The Sedimentary Mn Cycle In Long Island Sound: Its Role As Intermediate Oxidant And The Influence Of Bioturbation, O2,And Corg Flux On Diagenetic Reaction Balances, Robert C. Aller

Journal of Marine Research

The potential importance of sedimentary Mn as a secondary oxidant and redox intermediate between O2 and Corg is often discounted in nearshore sediments. Study of the Mn cycle at 19 stations in Long Island Sound (LIS) demonstrates that sedimentary Mn can be a significant redox intermediate, accounting in many cases for 30–50% of the benthic O2 flux (annual mean ≈40 ± 35%). At some sites and times, the import of solid oxidant as Mn in suspended matter is also apparently greater than the dissolved O2 flux to the bottom. The relative importance of the Mn cycle …

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Photochemical Iron Reduction And Iron Bioavailability In Seawater, William L. Miller, Dana Kester Jan 1994

Photochemical Iron Reduction And Iron Bioavailability In Seawater, William L. Miller, Dana Kester

Journal of Marine Research

Photochemical redox cycling of iron in natural seawater may affect the availability of iron to phytoplankton for cellular growth. Fe(III) colloids that support only limited phytoplankton growth were added to coastal seawater at pH8 and exposed to simulated solar irradiation for varied time intervals. Photo-production of Fe(II) in the seawater samples was measured during each irradiation. Following irradiation, the marine diatom, Skeletonema costatum, was inoculated into each treatment and cell densities were monitored in batch cultures over the next ten days. Increases in steady state concentrations of Fe(II) were observed during irradiation and subsequent elevated phytoplankton growth was observed …

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Wind-Driven Secondary Circulation In Ocean Mesoscale, Dong-Kyu Lee, Peter Niiler, Alex Warn-Varnas, Steve Piacsek Jan 1994

Wind-Driven Secondary Circulation In Ocean Mesoscale, Dong-Kyu Lee, Peter Niiler, Alex Warn-Varnas, Steve Piacsek

Journal of Marine Research

A two-dimensional, numerical circulation model is used to study the response of a stratified, f-plane ocean current to wind stress forcing at the surface. Nonhydrostatic, primitive equations are integrated on a 3 m vertical and 400 m horizontal grid in a periodic domain perpendicular to the ocean current. Initially, a geostrophically balanced current [Vi(x, z)] with a maximum Rossby number of 0.16–0.8 is maintained against horizontal and vertical diffusion by a body force. A spatially uniform wind is applied along and across this jet. A secondary circulation is created as a result of the …

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Spring And Winter Water Mass Composition In The Brazil-Malvinas Confluence, Keitapu Maamaatuaiahutapu, Véronique C. Garçon, Christine Provost, Mostefa Boulahdid, Alejandro A. Bianchi Jan 1994

Spring And Winter Water Mass Composition In The Brazil-Malvinas Confluence, Keitapu Maamaatuaiahutapu, Véronique C. Garçon, Christine Provost, Mostefa Boulahdid, Alejandro A. Bianchi

Journal of Marine Research

Hydrographic data of the Confluence 1 cruise collected during austral spring (November 1988) have been analyzed to estimate relative mixing proportions of the various water masses of the Brazil-Malvinas Confluence region using a multiparameter analysis. Seven source water types (SWT) are identified in this region, and all are retained for the analysis: Thermocline Water (TW), Subantarctic Surface Water (SASW), Antarctic Intermediate Water (AAIW), Upper Circumpolar Deep Water (UCDW), North Atlantic Deep Water (NADW), Lower Circumpolar Deep Water (LCDW) and Weddell Sea Deep Water (WSDW). Tracers selected are temperature, salinity, dissolved oxygen and nutrients. Mixing proportions are quantified and plotted along …

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Contrasting Effects Of Substrate Mobility On Infaunal Assemblages Inhabiting Two High-Energy Settings On Fieberling Guyot, Lisa A. Levin, Elana L. Leithold, Thomas F. Gross, Cynthia L. Huggett, Claudio Dibacco Jan 1994

Contrasting Effects Of Substrate Mobility On Infaunal Assemblages Inhabiting Two High-Energy Settings On Fieberling Guyot, Lisa A. Levin, Elana L. Leithold, Thomas F. Gross, Cynthia L. Huggett, Claudio Dibacco

Journal of Marine Research

The influence of seamount-intensified flows on the structure of infaunal assemblages was examined at two sand-covered sites located 2.3 km apart atop the summit plain of Fieberling Guyot (32°27.6′N 127° 48.0′W). Both sites experience strong, tidal bottom currents with flows exceeding 20 cm/s on a daily basis (4 mab). Estimates of shear velocity (u*) did not differ significantly between the two sites. However, differences in sediment composition and density produced different sediment transport regimes at the two sites. At Sea Pen Rim (SPR), located on the NW perimeter (635 m), sedimentary particles were composed primarily of basaltic …

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Dense Overflow Into A Large Silled Embayment: Tidal Modulation, Fronts And Basin Modes, M. White, Alex E. Hay Jan 1994

Dense Overflow Into A Large Silled Embayment: Tidal Modulation, Fronts And Basin Modes, M. White, Alex E. Hay

Journal of Marine Research

A dense bottom overflow into a 100-km scale silled embayment has been observed for a 70-day period using a coherent array of current meters and thermistor chains. As the internal Rossby radius is less than the width of the bay, the overflow is controlled by rotational dynamics. The flow is strongly modulated by the tide at diurnal, semi-diurnal and fortnightly periods. This causes a series of cold temperature fronts, associated with separate overflow events, to pass through the mooring array. The overflow is also modulated at periods of 2–3 days. This appears to be associated with the interaction of the …

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The Recruitment Patterns Of An Estuarine Copepod: A Biological-Physical Model, Sanjay Gupta, Darcy J. Lonsdale, Dong-Ping Wang Jan 1994

The Recruitment Patterns Of An Estuarine Copepod: A Biological-Physical Model, Sanjay Gupta, Darcy J. Lonsdale, Dong-Ping Wang

Journal of Marine Research

A biological-physical model was developed to study the population growth of Coullana canadensis (Willey), a meroplanktonic copepod, in the Saco River estuary, Maine. The biological processes were derived from extensive laboratory and field data, and the physical processes were based on a comprehensive estuarine hydrodynamic model. The study found that the physical environment significantly altered the seasonal pattern of population growth from that predicted from the biological model. Nauplii were lost from the estuary due to flushing in spring and early summer, and thus, the timing of the peak in copepod recruitment was delayed until late summer. A …

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Phytoplankton Dynamics Associated With A Geostrophic Front: Ecological And Biogeochemical Implications, Hervé Claustre, Philippe Kerhervé, Jean Claude Marty, Louis Prieur, Christianne Videau, Jean-Henri Hecq Jan 1994

Phytoplankton Dynamics Associated With A Geostrophic Front: Ecological And Biogeochemical Implications, Hervé Claustre, Philippe Kerhervé, Jean Claude Marty, Louis Prieur, Christianne Videau, Jean-Henri Hecq

Journal of Marine Research

Using phytoplankton pigments as biomarkers, we investigated the relationship between the physical forcing and the resulting biological, ecological and biogeochemical properties of the geostrophic front of the Eastern Alboran Sea. (1) Typical frontal sites present biomass levels averaging 60 mg chl a m−2 (up to 100 mg m−2), whereas the adjacent zones (typical Atlantic and Mediterranean) are characterized by an average integrated chlorophyll biomass of 20 mg chl a m−2. (2) The phytoplankton biomass at front is diatom-dominated and differs markedly from the adjacent zones (typical Atlantic and Mediterranean), flagellate- and cyanobacteria-dominated. Therefore, high biomasses …

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Species Assemblages Of Leptocephali In The Subtropical Convergence Zone Of The Sargasso Sea, Michael J. Miller, James D. Mccleave Jan 1994

Species Assemblages Of Leptocephali In The Subtropical Convergence Zone Of The Sargasso Sea, Michael J. Miller, James D. Mccleave

Journal of Marine Research

Species assemblages of leptocephali are described in relation to density in the Subtropical Convergence Zone (STCZ) of the Sargasso Sea. Seven transects across fronts were made during four cruises in the late winter or early spring of 1983, 1985 and 1989. About 50 species from 13 families of eels were collected at 66 stations, but fewer than 10 species were abundant in all transects. Four oceanic species, two Anguilla species and Conger oceanicus appeared to be spawning in the STCZ. Leptocephali of most species whose adults inhabit the continental shelf were consistently large in size and were more abundant at …

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Parameter Space Exploration Of An Ocean General Circulation Model Using An Isopycnal Mixing Parameterization, William A. Gough, William J. Welch Jan 1994

Parameter Space Exploration Of An Ocean General Circulation Model Using An Isopycnal Mixing Parameterization, William A. Gough, William J. Welch

Journal of Marine Research

In this study we have employed statistical methods to efficiently design experiments and analyze output of an ocean general circulation model that uses an isopycnal mixing parameterization. Full ranges of seven inputs are explored using 51 numerical experiments. Fifteen of the cases fail to reach satisfactory equilibria. These are attributable to numerical limitations specific to the isopycnal model. Statistical approximating functions are evaluated using the remaining cases to determine the dependency of each of the six scalar outputs on the inputs. With the exception of one output, the approximating functions perform well. Known sensitivities, particularly the importance of diapycnal (vertical) …

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Generalized Two-Layer Models Of Ocean Circulation, Rick Salmon Jan 1994

Generalized Two-Layer Models Of Ocean Circulation, Rick Salmon

Journal of Marine Research

The assumption that surfaces of constant temperature and potential vorticity coincide leads to an exact, time-dependent reduction of the ideal thermocline equations in an ocean basin of arbitrary shape. After modifications to include forcing, dissipation, and the presence of the equator, these reduced equations form the basis for numerical models that are both more realistic and easier to solve than the conventional two-layer model.

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A Proposed Flux Constraint For Salt Fingers In Shear, Eric Kunze Jan 1994

A Proposed Flux Constraint For Salt Fingers In Shear, Eric Kunze

Journal of Marine Research

Towed ocean microstructure observations reveal that the temperature Cox number depends inversely on interface temperature-gradient Tz in the fingering-favorable thermohaline staircase east of Barbados. This implies fluxes independent of interface gradients. These conclusions are contrary to theoretical expectations from a finger Froude number stability criterion, |Δw|/N < 1.0: (i) Cox numbers independent of temperature gradient, and (ii) fluxes varying linearly with temperature gradient. We propose a hybrid wave/finger Froude number stability criterion, |(uz − wx)(wy − vz)|N2 ≤ 1.0 which reduces to Uz|Vw|/N2 ≤ 1.0 for salt sheets (δ/δx = 0, | Δw| = wy) aligned with background (internal-wave) shear Uz. …

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Calcium Carbonate Dissolution Rates In Hydrothermal Vent Fields Of The Guaymas Basin, Richard A. Lutz, Michael J. Kennish, Alan S. Pooley, Lowell W. Fritz Jan 1994

Calcium Carbonate Dissolution Rates In Hydrothermal Vent Fields Of The Guaymas Basin, Richard A. Lutz, Michael J. Kennish, Alan S. Pooley, Lowell W. Fritz

Journal of Marine Research

Analysis of bivalve shell fragments that were embedded in epoxy blocks, mounted on titanium stakes, and deployed by DSRV Alvin at 5 sites in the Southern Trough of the Guaymas Basin (27°00′N, 111°24.55′W; depth 2012 m) indicates significant variation of calcium carbonate dissolution in in situ exposures of more than 900 days. Arrays of shell fragments of six bivalve species (i.e., Bathymodiolus thermophilus, Calyptogena magnifica, Calyptogena sp., Corbicula fluminea, Crassostrea virginica and Mytilus edulis) were positioned −17 cm, −7 cm and −2.5 cm below the sediment-water interface and 2.5 cm, 7 cm and 17 cm above the sediment-water interface …

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Currents Under Land-Fast Ice In The Canadian Arctic Archipelago Part 2: Vertical Mixing, R. F. Marsden, R. G. Ingram, L. Legendre Jan 1994

Currents Under Land-Fast Ice In The Canadian Arctic Archipelago Part 2: Vertical Mixing, R. F. Marsden, R. G. Ingram, L. Legendre

Journal of Marine Research

During an acoustic Doppler current profiler (ADCP) study of the velocity field under land-fast ice, coincident CTD casts showed three instances of pronounced instability in the water column, immediately above and below the pycnocline. In this paper we demonstrate that the density inversions are associated with the passage of high frequency linear internal waves and finite amplitude waves. Contours of ADCP acoustic return intensity display pronounced vertical eddy-like features which may indicate overturning. A Richardson number calculation showed that even the most highly stratified portion of the pycnocline had sufficient vertical velocity shear to promote dynamic instability. Finally, we calculate …

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