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Inertial Gyres In Decaying And Forced Geostrophic Turbulence, Patrick F. 0 Jan 1992

Inertial Gyres In Decaying And Forced Geostrophic Turbulence, Patrick F. 0

Journal of Marine Research

Numerical simulations of the motion of a turbulent homogeneous fluid in a rectangular beta-plane ocean basin are conducted to examine the influence of lateral boundary conditions on the development of inertial circulations. Three different boundary conditions are considered. Firstly, with a condition of zero vorticity gradient normal to the boundary, inertial Fofonoff gyres, which coincide with the maximum entropy solution of statistical mechanics, develop from the release of an initial random eddy field. Secondly, under a condition of no-stress (free-slip) at the boundary, inertial gyres resembling the Fofonoff flow develop. However, in this case, the linear relationship between potential vorticity …

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Deposit And Suspension Feeding In Oscillatory Flows And Sediment Fluxes, Douglas C. Miller, Michael J. Bock, Elizabeth J. Turner Jan 1992

Deposit And Suspension Feeding In Oscillatory Flows And Sediment Fluxes, Douglas C. Miller, Michael J. Bock, Elizabeth J. Turner

Journal of Marine Research

We present a survey of feeding behavior of benthic organisms in oscillatory flow and sediment fluxes. These results are based on seventeen species from five phyla and several feeding guilds from an intertidal sandflat and the continental shelf of the Mid-Atlantic coast, U.S.A. General responses to oscillatory flows are: (1) nearly immediate change in feeding behavior or position of feeding appendage when flow is initiated, (2) decrease in feeding area for surface deposit feeders, often (3) alteration of feeding mode, and when anatomically permitted (4) rotation of feeding appendages to track flow direction. At high sediment fluxes, responses are functional …

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Active Habitat Selection By Capitella Sp. I Larvae. Ii. Multiple-Choice Experiments In Still Water And Flume Flow, Judith P. Grassie, Cheryl Ann Butman, Suan W. Mills Jan 1992

Active Habitat Selection By Capitella Sp. I Larvae. Ii. Multiple-Choice Experiments In Still Water And Flume Flow, Judith P. Grassie, Cheryl Ann Butman, Suan W. Mills

Journal of Marine Research

Experiments on larval settlement of the opportunistic polychaete, Capitella sp. I, using three natural sediment treatments from the Buzzards Bay area (organic-rich mud from Sippewissett Marsh, organic-rich mud from New Bedford Harbor and low-organic sand from off the Weepecket Islands), and a glass bead mixture similar in grain size distribution to the New Bedford Harbor mud, were carried out in still water and two flume flows (near-surface velocities of 5 cm s−1 and 15 cm s−1; boundary-shear velocities of 0.26 cm s−1 and 0.64 cm s−1). For all three flow conditions the larvae settled …

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Active Habitat Selection By Capitella Sp. I Larvae. I. Two-Choice Experiments In Still Water And Flume Flow, Cheryl Ann Butman, Judith P. Grassie Jan 1992

Active Habitat Selection By Capitella Sp. I Larvae. I. Two-Choice Experiments In Still Water And Flume Flow, Cheryl Ann Butman, Judith P. Grassie

Journal of Marine Research

Sediment selection by settling larvae of the opportunistic polychaete Capitella sp. I was determined in laboratory still-water and flume experiments, where larvae were given a choice between two highly contrasting sediment treatments. In most cases, 2-h experiments were conducted with a natural, organic-rich mud and an abiotic, glass-bead mixture with a grain-size distribution similar to the mud, as the sediment treatments. Spatial settlement patterns were also determined in sediment arrays containing mud only. Two types of flume flows were tested, both with a near-surface velocity of ∼5 cm s−1, but one flow was cyclical, varying between about 2 …

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Effects Of Polychaetes On Silicate Dynamics And Fluxes In Sediments: Importance Of Species, Animal Activity And Polychaete Effects On Benthic Diatoms, Roberta L. Marinelli Jan 1992

Effects Of Polychaetes On Silicate Dynamics And Fluxes In Sediments: Importance Of Species, Animal Activity And Polychaete Effects On Benthic Diatoms, Roberta L. Marinelli

Journal of Marine Research

Laboratory experiments tested the effects of two polychaetes, a surface deposit feeder Eupolymnia heterobranchia, and a head-down deposit feeder Abarenicola pacifica, on silicate dynamics in sediment porewaters and overlying waters. Experimental chambers of sediment containing an individual deposit feeder, and controls with no macrofauna, were studied over a one month period during the summers of 1989 and 1990. Measurements included temporal changes in vertical depth profiles of pore water silicate concentrations, concurrent determinations of silicate accumulation in the water column, and the activities of experimental. organisms. A diffusion-nonlocal exchange-reaction model was devised to determine, from the pore water profiles, both …

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Nutrient And Biogenic Particulate Distributions, Primary Productivity And Nitrogen Uptake In The Weddell-Scotia Sea Marginal Ice Zone During Winter, Glenn F. Cota, Walker O. Smith Jr., David M. Nelson, Robin D. Muench, Louis I. Gordon Jan 1992

Nutrient And Biogenic Particulate Distributions, Primary Productivity And Nitrogen Uptake In The Weddell-Scotia Sea Marginal Ice Zone During Winter, Glenn F. Cota, Walker O. Smith Jr., David M. Nelson, Robin D. Muench, Louis I. Gordon

Journal of Marine Research

During austral winter of 1988, we determined the distributions of inorganic nutrients (nitrate, silicic acid, phosphate, nitrite and ammonium) and particulate materials (chlorophyll, biogenic silica, particulate organic carbon and particulate organic nitrogen), as well as primary productivity and rates of nutrient (NO3− and NH4+) uptake in the upper 150 m of the marginal ice zone of the Weddell-Scotia Sea. Nutrient concentrations were high and particulate matter levels were low throughout the study area, but occasionally nutrient minima and particulate maxima occurred near the ice edge associated with warm-core eddies. Chlorophyll concentrations and primary productivity averaged …

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A Model For Death Assemblage Formation: Can Sediment Shelliness Be Explained?, Eric N. Powell Jan 1992

A Model For Death Assemblage Formation: Can Sediment Shelliness Be Explained?, Eric N. Powell

Journal of Marine Research

A numerical model for carbonate (shell) accumulation in marine sediments is proposed. Sediment shelliness is controlled by carbonate addition, taphonomic loss, carbonate reorganizing processes, and sedimentation rate. Using representative rates of carbonate production, taphonomic loss, and sedimentary carbonate content, the model shows that insufficient carbonate is produced today in many environments to explain sedimentary carbonate content and that most produced carbonate must be preseIVed despite a generally high capacity for taphonomic loss. An anthropogenically-produced decrease in carbonate production over the last ∼100 yr may explain the former. Representative rates of burial and sedimentation, and a temporal and spatial offset between …

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The Dynamic Changes Of Stable Isotopic Ratios Of Carbon And Nitrogen In Suspended And Sedimented Particulate Organic Matter During A Phytoplankton Bloom, Takeshi Nakatsuka, Nobuhiko Handa, Eitaro Wada, Chi Shing Wong Jan 1992

The Dynamic Changes Of Stable Isotopic Ratios Of Carbon And Nitrogen In Suspended And Sedimented Particulate Organic Matter During A Phytoplankton Bloom, Takeshi Nakatsuka, Nobuhiko Handa, Eitaro Wada, Chi Shing Wong

Journal of Marine Research

The dynamic changes of carbon and nitrogen stable isotopic ratios in suspended and sedimented particulate matter were observed together with many other chemical and biological properties during a phytoplankton bloom induced by nutrient addition in a controlled ecosystem enclosure (CEE, about 70 m3) in Saanich Inlet, British Columbia, Canada. Both of the stable isotopic ratios of carbon (δ13C) and nitrogen (δ15N) in suspended particulate organic matter showed characteristic patterns of variations in surface water during the bloom. The δ13C of suspended particulate matter increased with the growth of phytoplankton population and decreased …

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The Radiolarian Fauna At The Ice Edge In The Greenland Sea During Summer, 1988, N. R. Swanberg, L. K. Eide Jan 1992

The Radiolarian Fauna At The Ice Edge In The Greenland Sea During Summer, 1988, N. R. Swanberg, L. K. Eide

Journal of Marine Research

Radiolaria were sampled from the plankton at 18 stations during two cruises in the Greenland Sea during summer, 1988. A total of 43 species or categories of radiolaria was found, but over 90% of the radiolarian fauna was dominated by adults or juveniles of 4 species: the spumellarian, Actinomma leptodermum and the nassellaria, Amphimelissa setosa, Pseudodictyophimus gracilipes, and Peridium longispinum. The stations sampled ranged from ice-covered areas high in nutrients to open water areas which were depleted in nutrients. These stations encompassed a gradient in the composition of the radiolarian fauna from an assemblage dominated by juveniles and adults …

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The Rise Of Bubbles In A Glass Tube And The Spectrum Of Bubbles Produced By A Splash, P. A. Bowyer Jan 1992

The Rise Of Bubbles In A Glass Tube And The Spectrum Of Bubbles Produced By A Splash, P. A. Bowyer

Journal of Marine Research

Bubbles produced by a volume of 500 cc of water falling through a distance of 1.07 m into a water-filled basin were allowed to rise into an adjacent water-filled tube whose top was sealed at a level of 1.7 m above the level of water in the basin. The rise of these bubbles was recorded on video at a height of 1.5 m above the level of the splash: larger bubbles were recorded first. A model has been devised to describe the rise of such bubbles. The rise speed of the bubbles at the level of the video camera decreased …

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Upwelling And Outwelling Effects On The Benthic Regime Of The Continental Shelf Off Galicia, Nw Spain, E. López-Jamar, R. M. Cal, G. González, R. B. Hanson, J. Rey, G. Santiago, K. R. Tenore Jan 1992

Upwelling And Outwelling Effects On The Benthic Regime Of The Continental Shelf Off Galicia, Nw Spain, E. López-Jamar, R. M. Cal, G. González, R. B. Hanson, J. Rey, G. Santiago, K. R. Tenore

Journal of Marine Research

The benthic regime off the Galician coast of NW Spain was surveyed to assess biogenic enrichment from coastal upwelling and detritus outwelling from the rías, large coastal embayments: the Rías Altas along the northern and the Rías Bajas along the western coast, which have intense mussel aquaculture. Sediment samples were collected from 1984 to 1986 and used for geological, microbiological, and macrofaunal studies. Sub-bottom acoustic profiler records and grab and core samples identified two main mud deposits on the western shelf that were aligned north to south and parallel with the coastline. The major axis of the mud deposit, which …

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The Equatorial Basin Response To A Rossby Wave Packet: The Effects Of Nonlinear Mechanism, Hong Ma Jan 1992

The Equatorial Basin Response To A Rossby Wave Packet: The Effects Of Nonlinear Mechanism, Hong Ma

Journal of Marine Research

Responses of the equatorial ocean to a Rossby wave packet, which assumes the form of either a cyclonic or an anticyclonic vortex pair, are simulated with the spectral element shallow water equation model (reduced gravity). We found that during the course of the western boundary reflection of an incoming equatorial Rossby wave packet, strong wave-wave interaction has significant influence on local dynamic and kinetic structures in the western tropical ocean. In the case of the western boundary reflection of a cyclonic Rossby wave vortex pair, the nonlinear effect tends to induce a strong, long-lasting eastward equatorial current; while in the …

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The Stability Of A Canonical Front, John Kroll Jan 1992

The Stability Of A Canonical Front, John Kroll

Journal of Marine Research

The stability of a geostrophic frontal current of constant slope over a stratified ocean is investigated using asymptotic techniques for large horizontal wavenumber and a small Burger number. The front is called canonical because it should approximate the edges of eddies or boundary currents. Results show that the front is unstable for an along the front wavenumber greater than f/V0 where V0 is the current velocity. But the instability is confined to a region near the vertex of the front of horizontal extent 0(V0/f). The flow becomes more unstable for increasing …

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Integral Equation Approach To Tropical Ocean Dynamics: Part Ii-Rossby Wave Scattering From The Equatorial Atlantic Western Boundary, Paulo R. Holvorcem, Marcio L. Vianna Jan 1992

Integral Equation Approach To Tropical Ocean Dynamics: Part Ii-Rossby Wave Scattering From The Equatorial Atlantic Western Boundary, Paulo R. Holvorcem, Marcio L. Vianna

Journal of Marine Research

We develop a linear theory for the scattering of equatorial waves of a fixed frequency ω by islands and continental margins of arbitrary geometry by use of the boundary integral equation (BIE) method of Vianna and Holvorcem (Part I of this work). All the solutions of the equatorial β-plane dispersion relations at frequency ω are treated explicitly through the extensive use of exact Green's functions, so that the approach is more general and more rigorous than previous attempts to solve equatorial scattering problems, many of which employ the low-frequency and long-wave approximations. The numerical solution of the HIE is obtained …

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Numerical Modeling Of Larval Settlement In Turbulent Bottom Boundary Layers, Thomas F. Gross, Francisco E. Werner, James E. Eckman Jan 1992

Numerical Modeling Of Larval Settlement In Turbulent Bottom Boundary Layers, Thomas F. Gross, Francisco E. Werner, James E. Eckman

Journal of Marine Research

A time-dependent model of a tidal or wave bottom boundary layer has been developed to quantitatively evaluate the relative influences of vertical advection, turbulent mixing and shear, and near-bed behavior on settlement of planktonic larvae of benthic animals. The settlement behavior of larvae is modeled with a simple flux condition at the bed. This allows full time dependence to be included when determining settlement rates. For tidal oscillations, the model predicts that most settlement will occur at and near periods of slack water, whereas comparatively little settlement will occur during periods of stronger flow. In contrast, there should be little …

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Encounter Rate By Turbulent Shear Of Particles Similar In Diameter To The Kolmogorov Scale, P. S. Hill, A. R. M. Nowell, P. A. Jumars Jan 1992

Encounter Rate By Turbulent Shear Of Particles Similar In Diameter To The Kolmogorov Scale, P. S. Hill, A. R. M. Nowell, P. A. Jumars

Journal of Marine Research

To clarify the rate at which particles similar in size to the smallest eddies in a turbulent fluid encounter one another via turbulent shear, 3-D video motion analysis was used to make direct measurements of relative velocities between closely spaced, near-neutrally buoyant, 700-μm mean diameter, polystyrene latex spheres suspended in an oscillating-grid turbulence tank. Smallest eddy size, termed the Kolmogorov scale, λ, was estimated as (ν3/ε)0.25 where ν is fluid viscosity and ε is the dissipation rate of turbulent kinetic energy. For runs made in water, the effective particle diameter examined was ≈ 3–6 times …

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Separation And Recirculation Of The North Brazil Current, Scott A. Condie Jan 1991

Separation And Recirculation Of The North Brazil Current, Scott A. Condie

Journal of Marine Research

The North Brazil Current separates from the French Guiana coast in the western tropical North Atlantic and a portion of the flow retroflects to form a recirculation zone known as the Demerara Anticyclone. The remainder of the North Brazil Current continues northwestward to join the Guiana Current. This part of the flow may be particularly significant, since it carries a cross-gyre transport of heat and mass from the tropical Atlantic into the subtropical gyre. An extension of the recirculation model of Cessi (1988), in which a quasi-geostrophic flow was driven by potential vorticity anomalies along a boundary, has been used …

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Spectral Time Scales For Mid-Latitude Eddies, William J. Schmitz Jr., James R. Luyten Jan 1991

Spectral Time Scales For Mid-Latitude Eddies, William J. Schmitz Jr., James R. Luyten

Journal of Marine Research

A few hundred current meter records of roughly one to two years' duration are now available from diverse locations in the world's oceans, primarily the North Atlantic. The shape of the spectrum for low-frequency ocean current fluctuations is shown to have a geographical distribution related to the general circulation. In the offshore segment of the Gulf Stream and Kuroshio Extension systems along with their recirculations, and near the Agulhas Current as well, normalized frequency distributions of eddy kinetic energy tend to be comparatively depth-independent and peaked at the mesoscale. However, in the immediate vicinity of current axes or fronts, spectral …

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Optics Of Heterotrophic Nanoflagellates And Ciliates: A Tentative Assessment Of Their Scattering Role In Oceanic Waters Compared To Those Of Bacterial And Algal Cells, André Morel, Yu-Hwan Ahn Jan 1991

Optics Of Heterotrophic Nanoflagellates And Ciliates: A Tentative Assessment Of Their Scattering Role In Oceanic Waters Compared To Those Of Bacterial And Algal Cells, André Morel, Yu-Hwan Ahn

Journal of Marine Research

Heterotrophic nanoflagellates and naked ciliates have been isolated from open sea waters and separately grown by using free living marine bacteria as food. The modal diameters of purified (by differential screening) populations are about 3 and 12.5 μm, respectively. The spectral determination of their absorption and scattering properties have been carried out. By combining these values with the cell number density and size distribution function, simultaneously measured, the efficiency factors for absorption and scattering at the level of individual cells can be derived. From these factors and by using the anomalous diffraction theory, the relative index of refraction can be …

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A Model Of The Diel Vertical Migration Of Zooplankton Based On Euphausiids, Valérie Andersen, Paul Nival Jan 1991

A Model Of The Diel Vertical Migration Of Zooplankton Based On Euphausiids, Valérie Andersen, Paul Nival

Journal of Marine Research

A detailed model of the diel vertical migration of euphausiids, particularly that of Meganyctiphanes norvegica adults in the northwestern Mediterranean Sea, is presented. It simulates the temporal and vertical variation of the euphausiid biomass over the diel cycle in the water column from 0 to 700 m depth. Migration is influenced by two external factors: food (phyto- and zooplankton) and light. Light is assumed to influence migration both by its intensity with the occurrence of an optimal value, and by its relative change in intensity, which affects the ascent or descent of the organisms. The general features of the diel …

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The Accumulation Of Barium By Marine Phytoplankton Grown In Culture, Nicholas S. Fisher, Robert R. L. Guillard, Donald C. Bankston Jan 1991

The Accumulation Of Barium By Marine Phytoplankton Grown In Culture, Nicholas S. Fisher, Robert R. L. Guillard, Donald C. Bankston

Journal of Marine Research

Marine phytoplankton have been implicated as potentially important vectors for the vertical transport of barium in the oceans. To better assess the extent to which phytoplankton can influence the geochemical cycling of barium, its bioconcentration was studied in 21 clones of 19 species of marine phytoplankters belonging to 9 algal classes. Barium levels in the ash ranged from less than 2 μg g–1 for the coccolithophore Emiliania huxleyi and the red alga Porphyridium cruenturn to 589 μg g–1 for the flagellate Tetraselmis levis. Concentrations ≥4000 μg g–1, previously reported for certain samples of diatom ash were …

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Geostrophic Transport Of The South Equatorial Current In The Atlantic, Lothar Stramma Jan 1991

Geostrophic Transport Of The South Equatorial Current In The Atlantic, Lothar Stramma

Journal of Marine Research

Geostrophic transport calculations from historical data of the equatorial South Atlantic are presented for the investigation of the flow field in the South Equatorial Current region. On the basis of water mass distribution, the potential density surface of σ1 = 32.15 kg m–3 is used as a reference for geostrophic shears. This reference surface is located at a depth of 1000 to 1200 m and represents the boundary between the upper branch of the Circumpolar Deep Water and the Upper North Atlantic Deep Water. The southern band of the South Equatorial Current (SSEC) is fed by the Benguela …

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Buoyancy-Driven Circulation As Horizontal Convection On Β-Plane, Nobuo Suginohara, Shigeaki Aoki Jan 1991

Buoyancy-Driven Circulation As Horizontal Convection On Β-Plane, Nobuo Suginohara, Shigeaki Aoki

Journal of Marine Research

The nature of the steady buoyancy-driven circulation is investigated using multi-level numerical models. An ocean which extends over the northern and southern hemispheres is forced by cooling in a confined region and heating in the rest of the ocean through the sea surface. As is already known, the circulation and associated thermal structure strongly depend upon the effect of the vertical diffusivity. This nature of the buoyancy-driven circulation is found in the thermodynamic balance. The vertical diffusion plays an essential role in the whole ocean domain. In counterbalancing the vertical diffusion, the horizontal advection at the deepest levels and the …

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Seasonal Variations Of Surface Dynamic Topography In The Tropical Atlantic: Observational Uncertainties And Model Testing, Christine Duchène, Claude Frankignoul Jan 1991

Seasonal Variations Of Surface Dynamic Topography In The Tropical Atlantic: Observational Uncertainties And Model Testing, Christine Duchène, Claude Frankignoul

Journal of Marine Research

A new analysis of the historical temperature and salinity profiles in the tropical Atlantic is done in order to estimate quantitatively the uncertainties in the climatological seasonal variations of 0/400 db dynamic topography. The uncertainties are described by an error covariance matrix which takes into account aliasing and measurement errors, the effect of data gaps and interpolation, as well as the uncertainty of the T-S method that was used to calculate the dynamic height. The standard deviation of the monthly means is found to range between 2 and 10 dyn cm, depending on the data density and the level of …

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Direct Measurement Of Dissolved Inorganic Nitrogen Exchange And Denitrification In Individual Polychaete (Nereis Virens) Burrows, Erik Kristensen, Mikael Hjorth Jensen, Robert C. Aller Jan 1991

Direct Measurement Of Dissolved Inorganic Nitrogen Exchange And Denitrification In Individual Polychaete (Nereis Virens) Burrows, Erik Kristensen, Mikael Hjorth Jensen, Robert C. Aller

Journal of Marine Research

The burrows of macroinfauna are significant sites of sediment-water nitrogen exchange and associated microbial activity. In this study, the exchange of dissolved inorganic nitrogen (DIN) and nitrogen cycle reaction rates were quantified in individual burrows of the estuarine polychaete Nereis virens. Burrow ventilation rate and DIN (NH4+, NO2−, NO3− and N2O) exchange were determined at 22°C in individual, inhabited burrows with and without the presence of C2H2 (an NH4+ oxidation, N2O reduction block). Ventilation cycles were unaffected by C2H2, …

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Early Diagenesis Of Chlorophyll-A In Long Island Sound Sediments: A Measure Of Carbon Flux And Particle Reworking, Mingyi Sun, Robert C. Aller, Cindy Lee Jan 1991

Early Diagenesis Of Chlorophyll-A In Long Island Sound Sediments: A Measure Of Carbon Flux And Particle Reworking, Mingyi Sun, Robert C. Aller, Cindy Lee

Journal of Marine Research

Sedimentary chlorophyll distributions reflect supply from primary production in overlying waters, transport during sedimentation/bioturbation, and alteration due to decomposition/transformation reactions. In Long Island Sound sediments, seasonal depth profiles of chlorophyll-a (Chl-a) often decreased exponentially within a few centimeters of the sediment-water interface, implying that initial decomposition rates of Chl-a were faster than surface sediment mixing rates. The highest surface sediment concentrations of Chl-a occurred in early spring, shortly after the spring bloom; the lowest concentrations occurred in summer. Chl-a was more concentrated at the shallow station (∼15 m) than at the deeper station (∼40 …

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Bubbles And The Air-Sea Exchange Of Gases In Near-Saturation Conditions, David K. Woolf, S. A. Thorpe Jan 1991

Bubbles And The Air-Sea Exchange Of Gases In Near-Saturation Conditions, David K. Woolf, S. A. Thorpe

Journal of Marine Research

The net air-sea transfer of gases is not simply proportional to the surface gradient of gas concentration as is widely assumed but, when proper account of bubbles is taken, is asymmetrical with a net invasion of gas at 100% saturation. The nitrogen and oxygen saturation levels and the variation of the composition of a bubble during its lifetime affect the transfer of all gases. The net transfer of gases is not a function of the size and depth of the bubbles and the concentration of dissolved gases alone, but is dependent on the composition of the bubbles and thus the …

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Time Scales Of Mesoscale Variability And Their Relationship With Space Scales In The North Atlantic, P. Y. Le Traon Jan 1991

Time Scales Of Mesoscale Variability And Their Relationship With Space Scales In The North Atlantic, P. Y. Le Traon

Journal of Marine Research

A systematic study of characteristic time scales of mesoscale variability over the North Atlantic was done using two years of Geosat data. Time scales are first characterized by 10° latitude by 10° longitude bins. A more detailed description was obtained by globally mapping the Sea Level Anomaly temporal correlation after one cycle (17.05 days). The scales are shortest in areas of high mesoscale activity (Gulf Stream, North Atlantic Current) while relatively long time scales are observed over the Mid-Atlantic Ridge and in the eastern part of the basin. In general, time scales are not proportional to space scales. Propagation velocities …

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Oxic And Anoxic Decomposition Of Tubes From The Burrowing Sea Anemone Ceriantheopsis Americanus: Implications For Bulk Sediment Carbon And Nitrogen Balance, Erik Kristensen, Robert C. Aller, Josephine Y. Aller Jan 1991

Oxic And Anoxic Decomposition Of Tubes From The Burrowing Sea Anemone Ceriantheopsis Americanus: Implications For Bulk Sediment Carbon And Nitrogen Balance, Erik Kristensen, Robert C. Aller, Josephine Y. Aller

Journal of Marine Research

Many marine infaunal animals form organic tube and burrow linings. The role of these materials in organic matter cycling and preservation in sediments is largely unknown. In the case examined here, the infaunal sea anemone, Ceriantheopsis americanus, (a common component of bottom communities along the east coast of North America) forms a leathery, fibrous tube lining 2–3 mm thick, ∼1 cm in diameter, and typically extending 20–30 cm into deposits. Tube fibers (∼2 mm long, 2–5 μm thick) formed from discharged specialized nematocyst cells, ptychocysts, are composed of a silk-like protein copolymer, cerianthin. Tubes incubated under oxic and anoxic conditions …

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Conservative Tracer Study Of Horizontal Sediment Mixing Rates In A Bathyal Basin, California Borderland, Robert A. Wheatcroft Jan 1991

Conservative Tracer Study Of Horizontal Sediment Mixing Rates In A Bathyal Basin, California Borderland, Robert A. Wheatcroft

Journal of Marine Research

In situ tracer (50–125 μm plastic particles) experiments conducted using the DSV Alvin over a two year period in the 1240 m deep Santa Catalina Basin (eastern Pacific) have yielded near-surface (0–1.5 cm) horizontal bioturbation rates of order 1–10 cm2yr–1. Vertical biodiffusivities obtained from the same and similar particulate tracers at the same site are approximately an order of magnitude less. Mixing of near-surface, coarse sediment in Santa Catalina Basin is anisotropic. Deeper within the sediment horizontal bioturbation is not diffusive on a two-year time scale, but would appear to be a form of mixing termed …

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