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Wave-Induced Boundary Mixing In A Partially Mixed Estuary, Daniel Bourgault, Daniel E. Kelley Jan 2003

Wave-Induced Boundary Mixing In A Partially Mixed Estuary, Daniel Bourgault, Daniel E. Kelley

Journal of Marine Research

We present observations that reveal the existence of horizontally propagating, tidally-driven, high-frequency internal wave (IW) packets in a channel of the partially mixed St. Lawrence Estuary. The packets propagate transversely to the channel axis and collide with the shoaling lateral boundaries. The structure and energy of IWs are diagnosed with a two-dimensional, nonlinear nonhydrostatic model, and the results are compared with weakly nonlinear Korteweg-de-Vries (KdV) theory. The behavior of IWs running into the shoaling lateral boundary is examined in terms of published laboratory and numerical experiments. Our analysis indicates that IWs break on the slope, during which 6% of their …

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Intermediate Water Masses Off South-Southwest Portugal: Chemical Tracers, Graça Cabeçadas, Maria J. Brogueira, Célia Gonçalves Jan 2003

Intermediate Water Masses Off South-Southwest Portugal: Chemical Tracers, Graça Cabeçadas, Maria J. Brogueira, Célia Gonçalves

Journal of Marine Research

Biogeochemical tracers, as dissolved oxygen and nutrients, were measured during several surveys carried out between 1999 and 2001, off south-southwestern Portugal. The dense vertical and horizontal sampling allows the extensions of intermediate water masses present in the region to be resolved. A subsurface minimum salinity water layer, exhibiting values of apparent oxygen utilization (AOU) in the range 40 – 60 μmol/kg and intruding into the study area mainly from the south-southwest, is proposed to be a remnant of the Subarctic Intermediate Water (SAIW). A deeper salinity minimum displaying high concentrations of nutrients and AOU (~100 μmol/kg) and identified as a …

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The Effect Of Fiddler Crab Burrowing On Sediment Mixing And Radionuclide Profiles Along A Topographic Gradient In A Southeastern Salt Marsh, Barbara J. Mccraith, Leonard R. Gardner, David S. Wethey, Willard S. Moore Jan 2003

The Effect Of Fiddler Crab Burrowing On Sediment Mixing And Radionuclide Profiles Along A Topographic Gradient In A Southeastern Salt Marsh, Barbara J. Mccraith, Leonard R. Gardner, David S. Wethey, Willard S. Moore

Journal of Marine Research

Fiddler crabs are one of the principal agents of bioturbation in intertidal salt marshes. The physical, chemical, and biological properties of sediments can be modified by fiddler crab burrowing activity. This study examined the effect of fiddler crab burrowing on sediment reworking and the distributions of 210Pb and 137Cs in salt marsh sediments at North Inlet Estuary, South Carolina. Fiddler crab burrow density, turnover, and volume were measured along a transect from the forest to the creek bank. Burrow density ranged between 40 and 300 burrows m-2 with highest densities at the creek bank. Sediment reworking is …

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Upper Ocean Control On The Solubility Pump Of Co2, Takamitsu Ito, Michael J. Follows Jan 2003

Upper Ocean Control On The Solubility Pump Of Co2, Takamitsu Ito, Michael J. Follows

Journal of Marine Research

We develop and test a theory for the relationship of atmospheric p CO2 and the solubility pump of CO2 in an abiotic ocean. The solubility pump depends on the hydrographic structure of the ocean and the degree of saturation of the waters. The depth of thermocline sets the relative volume of warm and cold waters, which sets the mean solubility of CO2 in the ocean. The degree of saturation depends on the surface residence time of the waters. We develop a theory describing how atmospheric CO2 varies with diapycnal diffusivity and wind stress in a simple, …

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How Estuaries Work: A Charlotte Harbor Example, Robert H. Weisberg, Lianyuan Zheng Jan 2003

How Estuaries Work: A Charlotte Harbor Example, Robert H. Weisberg, Lianyuan Zheng

Journal of Marine Research

We consider the time-averaged, estuarine circulation through a control volume analysis of its mechanical energy balance; hence the title of our paper: "How estuaries work." The venue is the Charlotte Harbor on Florida's west coast, and the analysis medium is the primitive equation ECOM3D-si model. We are motivated by an estuary classification dilemma. Being that estuarine circulation is buoyancy driven by the horizontal salinity gradient, and that the gradient increases with increasing vertical mixing as the salinity isolines rotate from horizontal to vertical, it follows that an increase in mixing should lead to an increase in circulation. Yet, at some …

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Form, Performance And Trade-Offs In Swimming And Stability Of Armed Larvae, Daniel Grünbaum, Richard R. Strathmann Jan 2003

Form, Performance And Trade-Offs In Swimming And Stability Of Armed Larvae, Daniel Grünbaum, Richard R. Strathmann

Journal of Marine Research

Diverse larval forms swim and feed with ciliary bands on arms or analogous structures. Armed morphologies are varied: numbers, lengths, and orientations of arms differ among species, change through development, and can be plastic in response to physiological or environmental conditions. A hydromechanical model of idealized equal-armed larvae was used to examine functional consequences of these varied arm arrangements for larval swimming performance. With effects of overall size, ciliary tip speed, and viscosity factored out, the model suggested trade-offs between morphological traits conferring high swimming speed and weight-carrying ability in still water (generally few arms and low arm elevations), and …

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Stability Of The Global Ocean Circulation: The Connection Of Equilibria Within A Hierarchy Of Models, Henk A. Dijkstra, Wilbert Weijer Jan 2003

Stability Of The Global Ocean Circulation: The Connection Of Equilibria Within A Hierarchy Of Models, Henk A. Dijkstra, Wilbert Weijer

Journal of Marine Research

We address the problem of the multiple equilibria of the thermohaline circulation in a hierarchy of models. The understanding of the relation between bifurcation diagrams of box models, two-dimensional models and those of a global ocean general circulation model, is facilitated through analysis of the equilibrium solutions of a three-dimensional Atlantic-like sector model with an open southern channel. Using this configuration, the subtle effects of the wind-stress field, the effects of continental asymmetry and the asymmetry in the surface freshwater flux can be systematically studied. The results clarify why there is an asymmetric Atlantic circulation under a near equatorially-symmetric buoyancy …

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The Characteristics Of The Recirculating Bulge Region In Coastal Buoyant Outflows, Greg Avicola, Pablo Huq Jan 2003

The Characteristics Of The Recirculating Bulge Region In Coastal Buoyant Outflows, Greg Avicola, Pablo Huq

Journal of Marine Research

A relatively large recirculating gyre, or bulge (anticyclonic buoyant lens) region attached to the source has been observed to occur in some numerical simulations and in some oceanic outflows. The purpose of this paper is to determine the dynamics of such recirculating bulge regions. Laboratory experiments were conducted for the purpose of examining the characteristics, evolution, and impact of a recirculating bulge in a coastal buoyant outflow. All experiments were performed such that the buoyant layer was thin compared to the total water depth, and the width of the bay exit was approximately equal to the internal Rossby deformation radius …

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Reply To: “Comments On ‘A Generic Length-Scale Equation For Geophysical Turbulence Models’ ”By L. Kantha And S. Carniel, Lars Umlauf, Hans Burchard Jan 2003

Reply To: “Comments On ‘A Generic Length-Scale Equation For Geophysical Turbulence Models’ ”By L. Kantha And S. Carniel, Lars Umlauf, Hans Burchard

Journal of Marine Research

Recently, Kantha and Carniel (2003) commented on some earlier work of Kantha (2003) and Umlauf and Burchard (2003) on the formulation of a generalized length-scale equation in Reynolds stress models for geophysical flows. With the present short note, we respond to their major criticism of the Umlauf and Burchard (2003) generic two-equation model...

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Seasonal To Interannual Upper-Ocean Variability In The Drake Passage, Janet Sprintall Jan 2003

Seasonal To Interannual Upper-Ocean Variability In The Drake Passage, Janet Sprintall

Journal of Marine Research

Year-round monitoring of the upper-ocean temperature variability in Drake Passage has been undertaken since September 1996 through repeat expendable bathythermograph (XBT) surveys. The closely spaced measurements (6-15 km apart) provide the first multi-year time series for examining seasonal to interannual variability in this Southern Ocean choke point. While the temperature sections reveal the seasonal variability in water mass formation of the upper layer, there was no seasonal signal evident below 200 m. Similarly, there was little seasonal cycle evident in the position of the Subantarctic Front, the Polar Front and the Southern Antarctic Circumpolar Current Front associated with the Antarctic …

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The Influence Of Macrofaunal Burrow Spacing And Diffusive Scaling On Sedimentary Nitrification And Denitrification: An Experimental Simulation And Model Approach, Franck Gilbert, Robert C. Aller, Stefan Hulth Jan 2003

The Influence Of Macrofaunal Burrow Spacing And Diffusive Scaling On Sedimentary Nitrification And Denitrification: An Experimental Simulation And Model Approach, Franck Gilbert, Robert C. Aller, Stefan Hulth

Journal of Marine Research

The influence of burrow spacing on sedimentary nitrification and denitrification was simulated experimentally using sediment plugs of different thicknesses immersed in aerated seawater reservoirs. Different plug thicknesses mimic different distances between oxygenated burrow centers and produce similar changes in aerobic-anaerobic reaction balances as a function of diffusive transport scaling. The thicknesses used were roughly equivalent to transport scales (interburrow spacing) that could be produced by burrow abundances of ~400 to 50,000 m-2, depending on burrow lumen radii (e.g., 0.05-1 cm). Following the exposure of anoxic sediment plugs to aerated water, an efficient aerobic nitrification zone was established within …

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Initiation Of A Doubly Diffusive Convection In A Stable Halocline, Melvin E. Stern Jan 2003

Initiation Of A Doubly Diffusive Convection In A Stable Halocline, Melvin E. Stern

Journal of Marine Research

A vertically stable density stratification with temperature gradient Tz < 0, salinity gradient Sz < 0, and with density compensating horizontal T/S gradients is unstable to lateral intrusions because the molecular heat diffusivity is much larger than the salt diffusivity. Previous marginal instability theory is extended to the supercritical regime. The fastest growing vertical wavelength (δz) is obtained in a model of a T/S front with finite lateral width (L*) and lateral salinity variation (ΔS). The value of δz ≈ ΔS/|Sz| varies only slightly with the parameters, and this result is applied to the smallest "step" …

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Variation Of Nonlocal Irrigation In A Subtidal Benthic Community, Stefan Forster, Arzhang Khalili, Jarmila Kitlar Jan 2003

Variation Of Nonlocal Irrigation In A Subtidal Benthic Community, Stefan Forster, Arzhang Khalili, Jarmila Kitlar

Journal of Marine Research

Irrigation, the effect of the pumping activity by benthic infauna on pore water solute distribution and fluxes, may be represented by a nonlocal irrigation function, α (units: 1/time) in the general diagenetic equation. We derived α from the distribution of a solute tracer, bromide, during laboratory incubations of sediment cores containing their natural faunal community. Sediments were sampled on 4 occasions over a period of one year from a site at 30 m depth in the southern North Sea. Fitting an irrigation function exponentially decaying with depth, we arrived at α-values ranging from 25 to >200 yr-1 at the sediment …

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The Pacific/Indian Ocean Pressure Difference And Its Influence On The Indonesian Seas Circulation: Part I—The Study With Specified Total Transports, William H. Burnett, Vladimir M. Kamenkovich, Arnold L. Gordon, George L. Mellor Jan 2003

The Pacific/Indian Ocean Pressure Difference And Its Influence On The Indonesian Seas Circulation: Part I—The Study With Specified Total Transports, William H. Burnett, Vladimir M. Kamenkovich, Arnold L. Gordon, George L. Mellor

Journal of Marine Research

The main objective of this paper is to investigate the overall balance of momentum and energy within the Indonesian Seas to better understand the factors that control the total transport of the Indonesian Throughflow. Two models are used in the investigation: a "first-step" heuristic channel model and a more sophisticated "second-step," barotropic numerical model that incorporates high-resolution coastline and bottom topography. The experiments show that the barotropic model develops typical horizontal circulation patterns for the region. An analysis of the overall momentum and energy balances suggests that the total transport of the Indonesian Throughflow does not depend exclusively on the …

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The Pacific/Indian Ocean Pressure Difference And Its Influence On The Indonesian Seas Circulation: Part Ii—The Study With Specified Sea-Surface Heights, Vladimir M. Kamenkovich, William H. Burnett, Arnold L. Gordon, George L. Mellor Jan 2003

The Pacific/Indian Ocean Pressure Difference And Its Influence On The Indonesian Seas Circulation: Part Ii—The Study With Specified Sea-Surface Heights, Vladimir M. Kamenkovich, William H. Burnett, Arnold L. Gordon, George L. Mellor

Journal of Marine Research

In Part II we construct new numerical solutions to further analyze our results in Part I (Burnett et al., 2003), that indicate the lack of a unique relationship between the Pacific/Indian Ocean pressure difference and the total transport of the Indonesian Throughflow (ITF). These new solutions involve perturbations of the sea level relative to the original solutions. We present detailed analyses of the overall momentum and energy balances for these new solutions to stay consistent with the procedures developed in Part I. The results validate our conclusions regarding the lack of a unique relationship between the pressure head and the …

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Comments On “A Generic Length-Scale Equation For Geophysical Turbulence Models” By L. Umlauf And H. Burchard, L. Kantha, S. Carniel Jan 2003

Comments On “A Generic Length-Scale Equation For Geophysical Turbulence Models” By L. Umlauf And H. Burchard, L. Kantha, S. Carniel

Journal of Marine Research

Umlauf and Burchard (2003) present a generic length-scale equation... for use in two-equation models of turbulence. However, because of the traditional form used for the diffusion term, it can be used at present for only negative values of n. We show that a simple modification of the diffusion term is sufficient to insure a more universal generic length-scale equation that is valid for all values of m and n, including positive values of n. We also show that an appropriate combination of exponents m and n will enable the generic length-scale equation to simulate any desired length-scale equation...

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Does The Nonlinearity Of The Equation Of State Impose An Upper Bound On The Buoyancy Frequency?, Trevor J. Mcdougall, John A. Church, David R. Jackett Jan 2003

Does The Nonlinearity Of The Equation Of State Impose An Upper Bound On The Buoyancy Frequency?, Trevor J. Mcdougall, John A. Church, David R. Jackett

Journal of Marine Research

Mixing in the ocean is usually accompanied by a net reduction in volume caused by the nonlinear nature of the equation of state. This contraction-on-mixing at a certain depth implies that the whole water column above this depth slumps a little and so suffers a reduction in gravitational potential energy. Under certain circumstances the gravitational potential energy of the entire water column can decrease as a consequence of mixing activity at a certain depth. We examine Fofonoff's hypothesis that in these circumstances the net reduction of gravitational potential energy of the whole water column causes a local increase in the …

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Simultaneous Data-Based Optimization Of A 1d-Ecosystem Model At Three Locations In The North Atlantic: Part Ii—Standing Stocks And Nitrogen Fluxes, Markus Schartau, Andreas Oschlies Jan 2003

Simultaneous Data-Based Optimization Of A 1d-Ecosystem Model At Three Locations In The North Atlantic: Part Ii—Standing Stocks And Nitrogen Fluxes, Markus Schartau, Andreas Oschlies

Journal of Marine Research

This study relates the performance of an optimized one-dimensional ecosystem model to observations at three sites in the North Atlantic Ocean: the Bermuda Atlantic Time Series Study (BATS, 31N 64W), the location of the North Atlantic Bloom Experiment (NABE, 47N 20W), and Ocean Weather Ship INDIA (OWS-INDIA, 59N 19W). The ecosystem model is based on nitrogen and resolves dissolved inorganic nitrogen (N), phytoplankton (P), zooplankton (Z) and detritus (D), therefore called the NPZD-model. Physical forcing, such as temperature and eddy diffusivities are taken from an eddy-permitting general circulation model of the …

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Simultaneous Data-Based Optimization Of A 1d-Ecosystem Model At Three Locations In The North Atlantic: Part I—Method And Parameter Estimates, Markus Schartau, Andreas Oschlies Jan 2003

Simultaneous Data-Based Optimization Of A 1d-Ecosystem Model At Three Locations In The North Atlantic: Part I—Method And Parameter Estimates, Markus Schartau, Andreas Oschlies

Journal of Marine Research

An optimization experiment is performed with a vertically resolved, nitrogen-based ecosystem model, composed of four state variables (NPZD-model): dissolved inorganic nitrogen (N), phytoplankton (P), herbivorous zooplankton (Z) and detritus (D). Parameter values of the NPZD-model are optimized while assimilating observations at three locations in the North Atlantic simultaneously, namely at the sites of the Bermuda Atlantic Time-Series Study (BATS; 31N 64W), of the North Atlantic Bloom Experiment (NABE; 47N 20W), and of Ocean Weather Ship-India (OWS-INDIA; 59N 19W). A method is described for a simultaneous optimization which effectively merges …

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Evaluation Of Excess 234th Activity In Sediments As An Indicator Of Food Quality For Deep-Sea Deposit Feeders, Amanda W. J. Demopoulos, Craig R. Smith, David J. Demaster, William L. Fornes Jan 2003

Evaluation Of Excess 234th Activity In Sediments As An Indicator Of Food Quality For Deep-Sea Deposit Feeders, Amanda W. J. Demopoulos, Craig R. Smith, David J. Demaster, William L. Fornes

Journal of Marine Research

Deep-sea deposit feeders selectively ingest large volumes of sediment. Knowledge of the nature of this selectivity will help to elucidate the limiting nutritional requirements and geochemical impacts of these abundant animals. Shallow-water and theoretical studies suggest that deep-sea deposit feeders should select particles rich in protein, bacterial biomass, and/or chloropigment concentrations. Recent studies indicate that deep-sea megafaunal deposit feeders exhibit strong gut enrichment of excess (xs) 234Th activity, even though 234Thxs lacks nutritional value. To explore the significance of selective ingestion of 234Thxs activity, we evaluated the correlations between 234Thxs activity and three …

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The Role Of Outflow Geometry In The Formation Of The Recirculating Bulge Region In Coastal Buoyant Outflows, Greg Avicola, Pablo Huq Jan 2003

The Role Of Outflow Geometry In The Formation Of The Recirculating Bulge Region In Coastal Buoyant Outflows, Greg Avicola, Pablo Huq

Journal of Marine Research

Density-driven coastal currents are a common feature in the world's coastal oceans. These currents may separate from the coastline due to variations in geometry. Past studies have shown that this separation may produce two distinctly different flow states: a continuation of the coastal current, or a recirculating gyre downshelf of, and attached to, the separation point. Laboratory experiments of coastal buoyant outflows (rotationally dominated, buoyancy driven) were undertaken to examine the role of bay geometry on the evolution of the outflow. Experiments were conducted on a rotating turntable in relatively deep water (such that the buoyant layer depth was much …

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On The Thermohaline Circulation In Flat Bottom Marginal Seas, Michael A. Spall Jan 2003

On The Thermohaline Circulation In Flat Bottom Marginal Seas, Michael A. Spall

Journal of Marine Research

The thermohaline circulation in an idealized marginal sea is studied using both numerical and analytical models. The circulation is forced by repeating an annual cycle of cooling in the interior of the marginal sea for 2 months and turning off the surface forcing for 10 months. The marginal sea is connected to an open ocean through a narrow strait, thus providing a means to equilibrate the cooling within the marginal sea by exchange with the open ocean. The resulting upper ocean circulation consists of a warm boundary current that flows into the marginal sea through the strait that is gradually …

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The Large-Scale Time-Mean Ocean Circulation In The Nordic Seas And Arctic Ocean Estimated From Simplified Dynamics, Ole Anders Nøst, Pål Erik Isachsen Jan 2003

The Large-Scale Time-Mean Ocean Circulation In The Nordic Seas And Arctic Ocean Estimated From Simplified Dynamics, Ole Anders Nøst, Pål Erik Isachsen

Journal of Marine Research

A simplified diagnostic model of the time-mean, large-scale ocean circulation in the Nordic Seas and Arctic Ocean is presented. Divergences in the surface Ekman layer are extracted from observed climatological wind stress fields. Similarly, divergences caused by the meridional thermal wind transport (relative to the bottom) are calculated from an observed climatological density field. These known quantities are then used to "force" the model's bottom geostrophic velocities. Both scaling arguments and direct observations show that for long time scales the bottom currents are closely aligned with contours of f/H, (where f is the Coriolis parameter and H is the …

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On The Role Of Biological Dynamics In Plankton Patchiness At The Mesoscale: An Example From The Eastern North Atlantic Ocean, M. A. Srokosz, A. P. Martin, M. J. R. Fasham Jan 2003

On The Role Of Biological Dynamics In Plankton Patchiness At The Mesoscale: An Example From The Eastern North Atlantic Ocean, M. A. Srokosz, A. P. Martin, M. J. R. Fasham

Journal of Marine Research

In situations where the direct physical forcing of biological processes, through nutrient supply or light limitation of phytoplankton, does not show significant spatial variability, it is demonstrated that the effects of the mesoscale circulation and population dynamics on plankton patchiness are in principle, separable. In this case, the physical stirring and mixing control the size and shape of structures seen in plankton distributions, whilst the biological dynamics controls the size of the populations within those structures. This is demonstrated using field observations and a simple process model. The field data, which come from mesoscale surveys of a region (16 -20W, …

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Modes Of Internal Thermohaline Variability In A Single-Hemispheric Ocean Basin, Lianke A. Te Raa, Henk A. Dijkstra Jan 2003

Modes Of Internal Thermohaline Variability In A Single-Hemispheric Ocean Basin, Lianke A. Te Raa, Henk A. Dijkstra

Journal of Marine Research

In this study, the internal modes of variability of the thermohaline ocean circulation in an idealized single-hemispheric basin are investigated. The modes are determined systematically by performing linear stability analyses of fully three-dimensional thermohaline flows. Relevant for the large-scale low-frequency variability of the flows are two kinds of oscillatory modes. The modes in one of these classes, which have an interdecadal time scale, are truly three-dimensional phenomena and are characterized by westward propagating temperature anomalies, while modes in the other class have a centennial time scale. The latter modes are shown to persist as internal modes of variability of two-dimensional …

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A Model Of Fluff Layer Erosion And Subsequent Bed Erosion In The Presence Of The Bioturbator, Hydrobia Ulvae, Francis Orvain, Pierre Le Hir, Pierre-Guy Sauriau Jan 2003

A Model Of Fluff Layer Erosion And Subsequent Bed Erosion In The Presence Of The Bioturbator, Hydrobia Ulvae, Francis Orvain, Pierre Le Hir, Pierre-Guy Sauriau

Journal of Marine Research

Previous studies have shown that the gastropod Hydrobia ulvae destabilizes the top layers of fine-grained sediments. This process is mediated by the formation of a "biogenic" fluff layer that includes tracks, faecal pellets and mucus. This fluff layer has been shown to be easily resuspended before general bed erosion. In order to examine how fluff layer and bed erosion interact, flume experiments were performed with fluid sediments of varying water contents. Ten thousand snails were placed and allowed to crawl for 5 h on the sediment surface, and then the resuspended sediment mass was measured in response to step-wise shear …

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Adaptive Model Of Dom Dynamics In The Surface Ocean, Markus Pahlow, Alain F. Vézina Jan 2003

Adaptive Model Of Dom Dynamics In The Surface Ocean, Markus Pahlow, Alain F. Vézina

Journal of Marine Research

The bulk of marine dissolved organic matter (DOM) forms a large, old, refractory carbon pool in the deep ocean, yet a small fraction in the surface ocean is actively involved in the global carbon cycle and may contribute significantly to the biological pump. We argue that present models of plankton and DOM in the surface ocean are incompatible with current knowledge of marine DOM dynamics. We present a plankton model with an adaptive formulation of bacteria-DOM interactions which is more consistent with observations. Our model reproduces net accumulation of DOM and is the first to reconcile the prevailing reports of …

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Oceans, Watersheds And Humans: Facts, Myths And Realities, Henry Huntington, Steve Colt Apr 2002

Oceans, Watersheds And Humans: Facts, Myths And Realities, Henry Huntington, Steve Colt

ISER Reports

Alaskans expect a great deal from their oceans and watersheds. Commercial fishing, sport fishing, subsistence hunting, recreation, offshore oil and gas development, transportation, and tourism are among the many ways the oceans, coast, watersheds, and their resources are used. These activities, however, can strain or break the capacity of the ecosystem to sustain them and they are not always compatible. Conflicts and controversies between different user groups are increasingly common. The role of societal forces in shaping the human-aquatic relationship is often under-appreciated, but can be critical. Protecting the health of Alaska’s oceans and watersheds requires managing the interactions between …

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The Seasonal And Spatial Variability Of Small-Scale Turbulence At The Iberian Margin, Toby J. Sherwin, Mark E. Inall, Ricardo Torres Jan 2002

The Seasonal And Spatial Variability Of Small-Scale Turbulence At The Iberian Margin, Toby J. Sherwin, Mark E. Inall, Ricardo Torres

Journal of Marine Research

Turbulence measurements were made off the northwest coast of Spain in January and August 1998. In winter the water column was vertically mixed to about 100 to 150 m, due to the combined effects of the vertical convection of warm northward-moving water and wind stress. A highly dissipative surface boundary layer was present at all times to a depth (of about 20 m) that correlated well with the local wind and wave amplitude. Below this layer dissipation levels decreased from about 10-7 m2 s-3 at a rate that was commensurate with 'law of the wall' boundary theory. …

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Effects Of Gut Chemistry In Marine Bivalves On The Assimilation Of Metals From Ingested Sediment Particles, Sarah B. Griscom, Nicholas S. Fisher, Robert C. Aller, Byeong-Gweon Lee Jan 2002

Effects Of Gut Chemistry In Marine Bivalves On The Assimilation Of Metals From Ingested Sediment Particles, Sarah B. Griscom, Nicholas S. Fisher, Robert C. Aller, Byeong-Gweon Lee

Journal of Marine Research

Bioavailability and uptake of trace metals by benthic animals are often assumed to be limited by authigenic sulfide minerals because of their low metal solubilities and reactivities under sedimentary conditions. However, digestive processes and gut conditions such as Eh, pH, and enzyme or surfactant activity, can affect the release of ingested metals in the gut and control uptake. In a series of laboratory experiments with the deposit-feeding clam, Macoma balthica and the suspension-feeding mussel, Mytilus edulis, we assessed assimilation efficiencies (AE) of radioisotopes of Ag, Cd and Co associated with acid-volatile sulfide (AVS), iron oxide (re-oxidized AVS), and reduced …

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