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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

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 …

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 …

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) …

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.

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 T_z 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, |(u_z − w_x)(w_y − v_z)|N² ≤ 1.0 which reduces to U_z|V_w|/N² ≤ 1.0 for salt sheets (δ/δx = 0, | Δw| = w_y) aligned with background (internal-wave) shear U_z. …

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 …

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 …

Currents Under Land-Fast Ice In The Canadian Arctic Archipelago Part 1: Vertical Velocities, R. F. Marsden, R. Paquet, R. G. Ingram

Journal of Marine Research

A 614 kHz acoustic Doppler current profiler was deployed through land-fast ice in Resolute Passage, in the Canadian Archipelago for 30 days in April and May 1992. It was demonstrated that in the mean, at tidal and at high frequencies the instrument was stable and aligned within 0.5° of vertical, permitting unambiguous measurement of the horizontal, and more importantly, the vertical velocity structure. The flow was dominated by tidal and high frequency (15 min period) oscillations. The K₁ and M₂ tidal currents were both approximately 10.0 cm s⁻¹, oriented along-channel. The K₁ component was constant …

Individual Physiological Responses To Environmental Hypoxia And Organic Enrichment: Implications For Early Soft-Bottom Community Succession, Thomas L. Forbes, Valery E. Forbes, Michael H. Depledge

Journal of Marine Research

Infaunal inhabitants of coastal marine sediments occupy environments along a continuum from extremely food-rich, low-oxygen regions to food-poor habitats with relatively high levels of available oxygen. In organic-rich sediments, efficient utilization of available organic matter by deposit-feeding macrofauna may often be limited by the supply of oxygen. Specific feeding rate, growth, and production efficiency were measured on single individuals of the polychaete Capitella species 1 to determine whether previously measured declines in growth rates in response to hypoxia were due to decreased feeding, decreased conversion efficiency, or both. Under otherwise constant conditions, feeding rate was determined by the nitrogen content …

Technological Change And Technology Strategy, Robert E. Evenson, Larry E. Westphal

Discussion Papers

No abstract provided.

Demand For Children In Low Income Countries, T. Paul Schultz

Discussion Papers

No abstract provided.

Human Capital, Family Planning And Their Effects On Population Growth, T. Paul Schultz

Discussion Papers

No abstract provided.

A Library Worthy Of The School: A History Of The Yale Divinity School Library Collections, Paul Stuehrenberg

Yale Divinity Library Occasional Publications

No abstract provided.

Financial Rehabilitation Of Public Sector Banks: Conceptual And Policy Aspects, Suman K. Bery

Documents

No abstract provided.

Racial Differences In Bone Turnover Rate And Hyperparathyroidism In Hemodialysis Patients, Wendy Wei-Yue Lou

Yale Medicine Thesis Digital Library

No abstract provided.

Investigation Of The Mechanism Responsible For The Decreased Transcription Of The P53 Tumor Suppressor Gene In The Human Squamous Carcinoma Cell Line A253, Ho-Sheng Lin

Yale Medicine Thesis Digital Library

No abstract provided.

Role Of Hypothalamic Neuropeptide Y In A Genetic Model Of Obesity : The Zucker Rat, Katherine E. Martin

Yale Medicine Thesis Digital Library

No abstract provided.

Effects Of Hyperbaric Exposure On Eyes With Intraocular Gas Bubbles, Stephen V. Jackman

Yale Medicine Thesis Digital Library

Air travel is known to be potentially hazardous for patients with intraocular gas bubbles (IGBs). These bubbles, which are used in the treatment of complicated retinal detachments, can last for up to a month depending on the combination of long-acting gases used. We hypothesized that the external pressure changes associated with hyperbaric oxygen therapy, SCUBA diving, or caisson work could be similarly dangerous.

To test this, we placed IGBs into the right eyes of 18 rabbits and exposed them to several hyperbaric pressure profiles. In all profiles, the intraocular pressure (IOP) in the left or control eyes remained constant while …

Purification Of A Novel Mid-Region Fragment Of Parathyroid Hormone-Related Protein And Evidence Of Its Secretion By Three Different Cell Types, Katherine Elizabeth Dee

Yale Medicine Thesis Digital Library

No abstract provided.

Functional Decline At Hospital Discharge In Elderly Surgical Patients, Anthony S. Burns

Yale Medicine Thesis Digital Library

No abstract provided.

Silent Cerebral Infarction In Patients With Nonrheumatic Atrial Fibrillation, Mark Louis Meyer

Yale Medicine Thesis Digital Library

No abstract provided.

Spatial And Temporal Distributions Of Sedimentary Chloropigments As Indicators Of Benthic Processes In Long Island Sound, Ming-Yi Sun, Robert C. Aller, Cindy Lee

Journal of Marine Research

Regular spatial and seasonal distribution patterns of sedimentary chloropigments occurred at 19 subtidal stations located in Long Island Sound (LIS) from MAY 1988 to APR 1989. Inventories of chloropigments were higher (2–10x) in western than central LIS, mirroring patterns of phytoplankton production in surface waters. Shallow water sediments (<25 m) received more chloropigments than deep stations (>25 m). Lateral resuspension and redistribution of particles, as shown by ²³⁴Th inventories, are partly responsible for these patterns. Seasonal variations of Chl-a inventories in LIS sediments follow the production pattern in the water column: higher values occur in spring and lower values in summer and fall. A time …

Frictional Decay Of Abyssal Boundary Currents, Parker Maccready

Journal of Marine Research

A theory is presented to explain the observed longevity of abyssal boundary currents flowing along sloping topography. Typically such currents are many Rossby radii wide, and their energy is dominantly potential, residing in the broad upturn of isopycnals near the slope. The rate of decay of energy, on the other hand, is governed by the much smaller kinetic energy of the flow absorbed by the bottom boundary layer. The spin-down time is thus increased by a (possibly large) factor of PE/KE times that required to dissipate the kinetic energy alone. The ratio PE/KE is calculated from data on two sections …

The Effect Of Current-Induced Stress Perturbation In A Coupled Atmosphere-Ocean Model, Lian Xie, Claes Rooth

Journal of Marine Research

In the presence of surface currents, a stress perturbation at the air-sea interface is induced by the surface currents. It is directly correlated to the surface current pattern, and thus causes a feed-back effect in the sea-air system. This effect is studied for an equatorial sea-air system of the geometry of the equatorial Pacific Ocean by using a simple coupled atmosphere-ocean model. It is shown that the effect of the current-induced stress perturbation appears as a damping mechanism for the ocean circulation in general. However, in the presence of a zonally-asymmetric surface wind field, the stress perturbation associated with the …

Aggregation And Sedimentation Processes During A Spring Phytoplankton Bloom: A Field Experiment To Test Coagulation Theory, Thomas Kiørboe, Claus Lundsgaard, Michael Olesen, Jørgen L. S. Hansen

Journal of Marine Research

Spring diatom blooms in temperate waters are often terminated by aggregation of the cells into large flocs and subsequent mass sedimentation of the phytoplankton to the sea floor. The rate of aggregate formation by physical coagulation depends on the concentration of suspended particles, on the turbulent shear that makes particles collide, and on their stickiness (= probability of adhesion upon collision). During a mixed diatom bloom in a shallow Danish fjord, for 3 weeks we monitored the concentration and stickiness of suspended particles and the species composition of the phytoplankton at 2–3 d intervals and we estimated the turbulent shear …

Internal Tidal Bores In The Nearshore: Warm-Water Fronts, Seaward Gravity Currents And The Onshore Transport Of Neustonic Larvae, Jesus Pineda

Journal of Marine Research

Nearshore temperature fluctuations are associated with energetic cross-shore two-way flows that influence the onshore transport of neustonic larvae. Water temperature near the surface and bottom at two nearshore stations off southern California (6 and 15 m water depth, respectively) can drop sharply and subsequently rise. Two or more consecutive drops and rises can occur at diurnal or semidiurnal periodicities. The temperature increases may be accompanied by energetic seaward bottom currents together with sharp-edged warm-water fronts. (Warm-water fronts are defined here as linear seasurface features dividing parcels of water of different temperature.) Shoreward-moving surface fronts divided bodies of water of different …

Flow Along And Across The Aleutian Ridge, R. K. Reed, P. J. Stabeno

Journal of Marine Research

During a synoptic hydrocast survey in September 1993 near the Aleutian Islands, net northward flow of Alaskan Stream water occurred through deep passes near 180 and 172W. This inflow (≈4 × 10⁶ m³ s⁻¹) was the source of the eastward flow in the Bering Sea north of the islands. The eastward flow, however, was weaker and more convoluted than the stream flow (≈7 × 10⁶ m³ s⁻¹, referred to 1000 db) south of the islands.

Signatures Of Stirring And Mixing Near The Gulf Stream Front, G. L. Hitchcock, T. Rossby, J. L. Lillibridge Iii., E. J. Lessard, E. R. Levine, D. N. Connors, K. Y. Børsheim, M. Mork

Journal of Marine Research

In October, 1986 the surface waters adjacent to the Gulf Stream front were surveyed with an undulating profiler to describe the finescale structure of the mixed layer. The profiler was a Seasoar equipped with a CTD and fluorometer. The survey first defined the structure of a cyclonic eddy which resembled frontal eddies of the South Atlantic Bight in sea surface temperature imagery. The Seasoar transects revealed, however, that the cyclonic eddy lacked a cold dome typically seen in frontal eddies. Farther downstream the Seasoar defined the structure of streamers of Gulf Stream and Shelf water wrapped about the southern edge …

Vortex Pair Model Of Langmuir Circulation, G. T. Csanady

Journal of Marine Research

Accumulating evidence shows spacing and length of surface convergences associated with Langmuir circulation to be random variables, their strength also variable, their lifetime limited. Analysis of several sets of quantitative observations reveals the probability distribution of windrow spacing to be lognormal. This suggests generation of surface convergences at random times and locations on the sea surface. Moving shear stress anomalies, under wind gusts or breaking long waves, are capable of generating surface convergence in their wakes, and are the type of random event likely responsible for the stochastic properties of windrows. The generation mechanism envisaged is a “forced” version of …

Measurements Of Internal Wave Band Eddy Fluxes Above A Sloping Bottom, Hans Van Haren, Neil Oakey, Chris Garrett

Journal of Marine Research

The boundary layer near a sloping bottom may have a major influence on the ocean's interior density structure (due to “boundary mixing”) and on its circulation (because of the arrest of the Ekman layer by buoyancy forces). As a first attempt to measure eddy fluxes of momentum and buoyancy, in order to quantify the mixing in this region, we have carried out a 5-day pilot experiment on a sloping side of Emerald Basin on the Scotian Shelf. A moored upward-looking 1.2 MHz ADCP and a thermistor chain mounted along its vertical axis returned analyzable data between 8 and 17 m …