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Influence Of Environmental Forcings On The Seasonality Of Dissolved Oxygen And Nutrients In The Bay Of Bengal, S. Sardessai, N. Ramaiah, S. Prasanna Kumar, S. N. De Sousa
Influence Of Environmental Forcings On The Seasonality Of Dissolved Oxygen And Nutrients In The Bay Of Bengal, S. Sardessai, N. Ramaiah, S. Prasanna Kumar, S. N. De Sousa
Journal of Marine Research
Studies on seasonal variability of oxygen and nutrients during three seasons namely SW monsoon, fall intermonsoon and spring intermonsoon indicate influence of physical forcings on the distribution of these hydrochemical properties in the subsurface layer. In the open ocean the Minimum Oxygen Layer (MOL ≤10 mu Mol L-1) during the southwest monsoon and fall intermonsoon is mostly confined to the north of 11N due to the penetration of high salinity water in the deeper waters of the central Bay. During spring intermonsoon MOL is mostly confined to the northern region between 14 to 20N with a narrow band …
A Fast Numerical Solution To The General Mass-Conservation Equation For Solutes And Solids In Aquatic Sediments, Peter Berg, Dennis Swaney, Søren Rysgaard, Bo Thamdrup, Henrik Fossing
A Fast Numerical Solution To The General Mass-Conservation Equation For Solutes And Solids In Aquatic Sediments, Peter Berg, Dennis Swaney, Søren Rysgaard, Bo Thamdrup, Henrik Fossing
Journal of Marine Research
Mathematical modeling of species transformations in aquatic sediments is usually based on numerical solutions to the same general one-dimensional mass-conservation equation and is likely to require substantial computation time. In this paper we present a fast numerical solution to this equation. The solution is suited for both single and multi-component models and it is based on an implicit control volume discretization of the general mass-conservation equation. The solution consists of two algorithms, one that decomposes the discretization matrix once and one that subsequently produces multiple solutions with minimal computational effort. A unique feature of these algorithms is that values of …
An Assessment Of The Use Of Sediment Traps For Estimating Upper Ocean Particle Fluxes, Ken O. Buesseler, Avan N. Antia, Min Chen, Scott W. Fowler, Wilford D. Gardner, Orjan Gustafsson, Koh Harada, Anthony F. Michaels, Michiel Rutgers Van Der Loeff, Manmohan Sarin, Deborah K. Steinberg, Thomas Trull
An Assessment Of The Use Of Sediment Traps For Estimating Upper Ocean Particle Fluxes, Ken O. Buesseler, Avan N. Antia, Min Chen, Scott W. Fowler, Wilford D. Gardner, Orjan Gustafsson, Koh Harada, Anthony F. Michaels, Michiel Rutgers Van Der Loeff, Manmohan Sarin, Deborah K. Steinberg, Thomas Trull
Journal of Marine Research
This review provides an assessment of sediment trap accuracy issues by gathering data to address trap hydrodynamics, the problem of zooplankton "swimmers," and the solubilization of material after collection. For each topic, the problem is identified, its magnitude and causes reviewed using selected examples, and an update on methods to correct for the potential bias or minimize the problem using new technologies is presented. To minimize hydrodynamic biases due to flow over the trap mouth, the use of neutrally buoyant sediment traps is encouraged. The influence of swimmers is best minimized using traps that limit zooplankton access to the sample …
Mismatch Between Community Respiration And The Contribution Of Heterotrophic Bacteria In The Ne Atlantic Open Ocean: What Causes High Respiration In Oligotrophic Waters?, Xosé Anxelu G. Morán, Valesca Pérez, Emilio Fernández
Mismatch Between Community Respiration And The Contribution Of Heterotrophic Bacteria In The Ne Atlantic Open Ocean: What Causes High Respiration In Oligotrophic Waters?, Xosé Anxelu G. Morán, Valesca Pérez, Emilio Fernández
Journal of Marine Research
Heterotrophic bacteria have long been considered as the major respirers of the open ocean. During a survey in the eastern N Atlantic Subtropical Gyre we measured 3H-leucine heterotrophic bacterial production (BP), 14C particulate primary production (PPP) and the O2 community metabolism rates: gross primary production (GPP), net community production (NCP) and community respiration (CR). We estimated heterotrophic bacterial respiration (BR) from BP and literature models of bacterial growth efficiency [BGE = BP/(BP + BR)]. BP was an order of magnitude lower than PPP (integrated means of 17 ± 2 and 207 ± 29 mg C m−2 …
Hurricane-Induced Destratification And Restratification In A Partially-Mixed Estuary, Ming Li, Liejun Zhong, William C. Boicourt, Shunli Zhang, Da-Lin Zhang
Hurricane-Induced Destratification And Restratification In A Partially-Mixed Estuary, Ming Li, Liejun Zhong, William C. Boicourt, Shunli Zhang, Da-Lin Zhang
Journal of Marine Research
Hurricane Isabel made landfall at the Outer Banks of North Carolina and moved past Chesapeake Bay on 18 –19 September 2003. The baroclinic response of this partially-mixed estuary to the passage of Isabel is investigated using the output from a regional atmosphere-ocean model. The hurricane-forced winds caused gradual deepening of the surface mixed layer, followed by rapid destratification in the water-column. The mixed-layer deepening appears to be driven by velocity shear and can be interpreted by a gradient Richardson number. Although strong winds caused complete mixing locally, a large longitudinal salinity gradient of about 10-4 psu m-1 persisted …
The Variability And Heat Budget Of The Upper Ocean Under The Chile-Peru Stratus, Keir Colbo, Robert Weller
The Variability And Heat Budget Of The Upper Ocean Under The Chile-Peru Stratus, Keir Colbo, Robert Weller
Journal of Marine Research
The persistent stratus clouds found west of Chile and Peru are important for the coupling of the ocean and atmosphere in the eastern Pacific and thus in the climate of the region. The relatively cool sea-surface temperatures found west of Peru and northern Chile are believed to play a role in maintaining the stratus clouds over the region. In October 2000 a buoy was deployed at 20S, 85W, a site near the center of the stratus region, in order to examine the variability of sea-surface temperature and the temporal evolution of the vertical structure of the upper ocean. The buoy …
Simulated Fiddler-Crab Sediment Mixing, Katherine Huang, Bernard P. Boudreau, Daniel C. Reed
Simulated Fiddler-Crab Sediment Mixing, Katherine Huang, Bernard P. Boudreau, Daniel C. Reed
Journal of Marine Research
Using a lattice-automaton model, we simulate the effects of fiddler crabs on the distribution of excess 210Pb in marsh sediments. Three previously-identified modes of bioturbation are investigated: (1) removal-and-fill, where material is excavated to the sediment-water interface and burrows, when abandoned, are subsequently filled by surface material, (2) removal-and-collapse, where the infilling occurs by collapse of the burrow walls, and (3) partial-compaction-and-collapse, where part of the excavated sediment is packed into the burrow wall and abandoned burrows subsequently collapse. These various mixing modes lead to somewhat different laterally-integrated 210Pbex profiles, which are also influenced …
Field Investigation On Seawater Temperature Variability In Relation To Horizontal Optical Gradient, Maciej Matciak, Bozena Wojtasiewicz
Field Investigation On Seawater Temperature Variability In Relation To Horizontal Optical Gradient, Maciej Matciak, Bozena Wojtasiewicz
Journal of Marine Research
The spatial variability of radiant energy absorption in seawater can result from the non-homogeneity of the concentration of its optically active components, such as chlorophyll or dissolved organic matter. This non-homogeneity leads to local changes in the radiant heating rate and consequent changes in water temperature. Besides a simple dependence, for instance when a higher phytoplankton concentration is accompanied by a temperature rise, a relation that is more complex may occur. A theoretical analysis suggested that sufficiently strong horizontal changes in seawater absorption may cause, in their close proximity, an additional increase or decrease in the heating rate. To confirm …
Thermohaline Structure And Variability In The Eastern Nansen Basin As Seen From Historical Data, David Walsh, Igor Polyakov, Leonid Timokhov, Eddy Carmack
Thermohaline Structure And Variability In The Eastern Nansen Basin As Seen From Historical Data, David Walsh, Igor Polyakov, Leonid Timokhov, Eddy Carmack
Journal of Marine Research
Newly available historical Russian data are used to quantify year-to-year variations in the structure and properties of the halocline and Atlantic Water layers in the eastern Nansen Basin. The data come from a series of aerial surveys of the central Arctic Ocean done during winter between 1973 and 1979, and repeated "Polygon" surveys of the shelf, slope, and basin north of Severnaya Zemlya in the 1980s, and thus allow a perspective on shelf-basin exchange. A water-mass census shows substantial survey-to-survey variability in several water-mass categories, with volumetric fluctuations of ∼17% in the Upper Polar Deep Water category, ∼14% in Atlantic …
Spatial Continuity Of Measured Seawater And Tracer Fluxes Through Nares Strait, A Dynamically Wide Channel Bordering The Canadian Archipelago, Andreas Münchow, Kelly K. Falkner, Humfrey Melling
Spatial Continuity Of Measured Seawater And Tracer Fluxes Through Nares Strait, A Dynamically Wide Channel Bordering The Canadian Archipelago, Andreas Münchow, Kelly K. Falkner, Humfrey Melling
Journal of Marine Research
Freshwater delivered as precipitation and runoff to the North Pacific and Arctic oceans returns to the Atlantic principally via the Canadian polar shelf and Fram Strait. It is conveyed as ice or freshened seawater. Here we use detailed ship-based measurements to calculate a snap-shot of volume, freshwater, and tracer fluxes through Nares Strait, a 500-km long waterway separating Greenland and Ellesmere Island. We use quasi-synoptic observations of current by ship-mounted acoustic Doppler current profiler (ADCP), of salinity and temperature by CTD probe and of dissolved nutrients by rosette bottle sampler on four cross-sections between 82 and 78N latitude. Data were …
The Role Of Westward Intensification In Potential Vorticity Homogenization, Toshihiro Sakamoto
The Role Of Westward Intensification In Potential Vorticity Homogenization, Toshihiro Sakamoto
Journal of Marine Research
Using a two-layer quasigeostrophic model with weak interfacial and bottom friction we propose a mechanism for potential vorticity homogenization in a non-eddying, wind-driven gyre closed through a viscous western boundary layer, to which the previous theory based on the Prandtl–Batchelor theorem cannot be applied. It is shown that there exist steady states in which the lower-layer potential vorticity in a large pool of closed geostrophic contours becomes substantially uniform. The homogenization process is dominated by advection and thus completed within a single passage through the gyre. This is because an O (1) anomaly of potential vorticity that is comparable to …
Dissipation In Hydraulic Transitions In Flows Through Abyssal Channels, S. A. Thorpe
Dissipation In Hydraulic Transitions In Flows Through Abyssal Channels, S. A. Thorpe
Journal of Marine Research
There is growing evidence from observations that mixing occurs in hydraulic jumps, or flow transitions, downstream of sills within channels connecting deep ocean basins or within submarine canyons on the flanks of mid-ocean ridges. Models with continuous profiles of velocity and density upstream and downstream of a transition, but conforming to continuity conditions, are devised to represent the mixing that occurs in a hydraulic jump in a stratified shear flow of finite depth moving over a horizontal boundary in a deep fluid. These are used to assess the conditions in which transitions may occur and to provide an estimate of …
Oxygen And Nitrogen Cycling In The Northeast Pacific – Simulations And Observations At Station Papa In 2003/2004, N. Steiner, S. Vagle, K. Denman, C. Mcneil
Oxygen And Nitrogen Cycling In The Northeast Pacific – Simulations And Observations At Station Papa In 2003/2004, N. Steiner, S. Vagle, K. Denman, C. Mcneil
Journal of Marine Research
A long-term air-sea exchange mooring has been maintained in the North Pacific near Ocean Station Papa (OSP, 145W, 50N) since September 2002 as part of the Canadian Surface Ocean Lower Atmosphere Study (C-SOLAS). The mooring provides a new long-term data set for gas measurements. In addition to Conductivity, Temperature and Depth (CTD) recorders at two depths, the mooring is equipped with ProOceanus Gas Tension Devices (GTDs) measuring the total gas pressure at four different depths, two oxygen sensors, two fluorometers for chlorophyll estimates, and an upward-looking 200 kHz echo-sounder for bubble measurements. Chlorophyll data have been added using SeaWiFS imagery …
Phytoplankton Pigment Distribution In The Northwestern Alboran Sea And Meteorological Forcing: A Remote Sensing Study, D. Macías, G. Navarro, F. Echevarría, C. M. García, J. L. Cueto
Phytoplankton Pigment Distribution In The Northwestern Alboran Sea And Meteorological Forcing: A Remote Sensing Study, D. Macías, G. Navarro, F. Echevarría, C. M. García, J. L. Cueto
Journal of Marine Research
A set of weekly-composite SeaWiFS (Sea-viewing Wide Field of view Sensor) imagery (from 1998 to 2004) has been used to asses the temporal and spatial variability of the surface chlorophyll distribution in the Northwestern Alboran Sea. Empirical Orthogonal Function (EOF) analysis of the images series shows the existence of three different regions in which surface chlorophyll presents a homogeneous temporal behavior in the neighborhood of the Strait of Gibraltar.The temporal patterns of surface chlorophyll concentrations in each region have been characterized by studying the role of several forcing factors, mainly the zonal component of the wind field.The first identified region …
The Geography Of Linear Baroclinic Instability In Earth’S Oceans, K. Shafer Smith
The Geography Of Linear Baroclinic Instability In Earth’S Oceans, K. Shafer Smith
Journal of Marine Research
Satellite observations reveal a mesoscale oceanic circulation dominated by turbulence that is correlated, in most cases, with local baroclinicity. Linear baroclinic instability theory has proved useful in understanding the time and space scales of atmospheric eddies. The question addressed here is, to what degree can the observed oceanic eddy activity be understood through a local, linear stability analysis? This question is addressed as follows. A local quasigeostrophic linear stability calculation is performed on a grid of wavenumbers, ranging in magnitude about the local deformation wavenumber, for each vertical profile in a dataset of neutral density for the world's oceans. The …
Transient Tracer Dynamics In A Lattice-Automaton Model Of Bioturbation, Daniel C. Reed, Bernard P. Boudreau, Katherine Huang
Transient Tracer Dynamics In A Lattice-Automaton Model Of Bioturbation, Daniel C. Reed, Bernard P. Boudreau, Katherine Huang
Journal of Marine Research
Mixing of sediments by benthic fauna represents a dominant transport process of solids in the majority of surficial marine deposits. Short-term mixing rates are often determined by fitting a transient, diffusive model of bioturbation to vertical profiles of introduced particles (e.g., luminophores). Previous field studies adopting this approach have noted that mixing intensity decreases with time and the nature of mixing progresses from advective or nonlocal transport to diffusive mixing. These observations have been attributed to "age-dependent" mixing. The present study employs a lattice-automaton model to investigate the short-term behavior of conservative transient tracers. Simulations demonstrate that despite constant, indiscriminate …
On The Vorticity Cycle Of The Loop Current, A. Lugo-Fernández, A. Badan
On The Vorticity Cycle Of The Loop Current, A. Lugo-Fernández, A. Badan
Journal of Marine Research
The inrushing/retraction behavior of the Loop Current (LC) in the eastern Gulf of Mexico can be represented by a recurrent cycle of vorticity input/output with a time scale of 0 to 16 months. This cycle is brought about as a balance between the accumulation of absolute vorticity in the LC and deep advection of vorticity to the Caribbean Sea. The vorticity time scale is directly proportional to the change in circulation around the LC and 2πH/Q0(f0 + ζ0); where H (∼800 m) is the thickness of the LC, Q0 is …
The Enso Signature In Sea-Surface Temperature In The Gulf Of California, Hugo Herrera-Cervantes, Daniel B. Lluch-Cota, Salvador E. Lluch-Cota, Guillermo Gutiérrez-De-Velasco S
The Enso Signature In Sea-Surface Temperature In The Gulf Of California, Hugo Herrera-Cervantes, Daniel B. Lluch-Cota, Salvador E. Lluch-Cota, Guillermo Gutiérrez-De-Velasco S
Journal of Marine Research
We analyzed 21 years of sea-surface temperature satellite images to explore the spatial signature of the El Niño-Southern Oscillation signal in the Gulf of California. We used empirical orthogonal function analysis to extract the principal mode of the nonseasonal sea-surface temperature variability and compared it to the spatial signature of the Southern Oscillation Index. The first mode accounted for 80% of nonseasonal variability and its amplitude time series was significantly correlated to the Southern Oscillation Index (r = −0.58,P < 0.01). The amplitude of this mode and its statistical relation to the El Niño is stronger during winter, which suggests that forcing of sea-surface temperature variability occurs through the disruption of the wind-driven upwelling corridor along the eastern coast due to El Niño-related atmospheric teleconnections. We also examined weekly time series of coastal sea-surface temperature coastal anomalies along the coast of North America, including the interior of the Gulf of California, during the strong 1997–98 El Niño. We found a poleward propagating signal that reached the mouth of the Gulf of California at the end of spring and continued its poleward propagation along the west coast of the peninsula slightly delayed; it also resulted in warming inside the Gulf of California. This observation may provide an explanation for the variable extension of the El Niño signature along the Pacific coast of North America.
Water Column Stability And Spring Bloom Dynamics In The Gulf Of Alaska, Stephanie A. Henson
Water Column Stability And Spring Bloom Dynamics In The Gulf Of Alaska, Stephanie A. Henson
Journal of Marine Research
The initiation of the Gulf of Alaska phytoplankton spring bloom is light limited, and therefore the onset of stratification is critical to primary productivity. A stability ratio, which represents the balance between mixing (tide and wind) and buoyancy (heat and freshwater) processes, is defined. When buoyancy dominates over mixing, stratification is possible. Use of model- and satellite-derived data allows maps of the spatial and temporal development of stratification to be constructed. Spatial variability in the dominant forcing components is also mapped. The onset of water column stability is closely linked to the timing of the phytoplankton spring bloom. Consideration of …
Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann
Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann
Journal of Marine Research
A one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology is used to investigate the response of phytoplankton community and carbon production and export to variations in physical and biochemical processes in the Cold Tongue region of the equatorial Pacific Ocean at 0N, 140W. Results show that high-frequency variability in vertical advection and temperature is an important mechanism driving the carbon export. Filtering out low frequency physical forcing results in a 30% increase in primary production and dominance of high-light adapted Prochlorococcus and autotrophic eukaryotes. Sensitivity studies show that iron availability is the primary control on carbon …
Rapid Consumption Of Phytoplankton And Ice Algae By Arctic Soft-Sediment Benthic Communities: Evidence Using Natural And 13c-Labeled Food Materials, Ming-Yi Sun, Michael L. Carroll, William G. Ambrose Jr., Lisa M. Clough, Li Zou, Glenn R. Lopez
Rapid Consumption Of Phytoplankton And Ice Algae By Arctic Soft-Sediment Benthic Communities: Evidence Using Natural And 13c-Labeled Food Materials, Ming-Yi Sun, Michael L. Carroll, William G. Ambrose Jr., Lisa M. Clough, Li Zou, Glenn R. Lopez
Journal of Marine Research
Reduction of sea ice in the Arctic may significantly alter the relative fluxes of phytoplankton and ice algae to the seafloor. To examine the response of Arctic benthic communities to changing food supplies, we incubated sediment cores collected from two sites (Smeerenburg Fjord, northwest Svalbard in May 2003 and Storfjord Trench, Barents Sea in May 2004) with controlled additions of natural phytoplankton and ice algal assemblages, and laboratory-cultured 13C-labeled ice algae (Nitzschia frigida, in 2004 only). We measured sediment respiration, pigments, lipid biomarkers, and compound-specific δ13C signals over the course of incubations. Both communities responded …
Modeling Sensitivity Of Biodiffusion Coefficient To Seasonal Bioturbation, Pascal Lecroart, Sabine Schmidt, Pierre Anschutz, Jean-Marie Jouanneau
Modeling Sensitivity Of Biodiffusion Coefficient To Seasonal Bioturbation, Pascal Lecroart, Sabine Schmidt, Pierre Anschutz, Jean-Marie Jouanneau
Journal of Marine Research
Biodiffusion coefficient is the predominant parameter used to constrain biological activity in marine sediments. Bioturbation characterization is important because of the dominant role it plays on the flux determination through the sediment-water interface. Biological mixing is quantified through models of radionuclides diagenesis by both a biodiffusion coefficient (Db) and a mixed depth (L) under the basic steady-state assumption. Based on a new global compilation of radionuclide data in marine sediments and on previously published modeling results, we show that short-live radionuclides are perfectly devoted to quantify biological mixing for sediments associated with λL2/Db lower than 125, λ representing …
Notes On The Modeling Of Methane In Aging Hydrothermal Plumes, G. C. Nihous, S. M. Masutani
Notes On The Modeling Of Methane In Aging Hydrothermal Plumes, G. C. Nihous, S. M. Masutani
Journal of Marine Research
Marine hydrothermal vent fields represent a unique environment for the study of aerobic microbial methane oxidation because of high methane concentrations and limited spatial and temporal scales. Earlier data collected in lateral plumes at the Endeavour Segment of the Juan de Fuca Ridge, including methane concentration, methane oxidation rate and stable carbon isotopic composition (δ13C), are carefully interpreted with a suite of simple analytical models. Methane oxidation is defined with a rate constant k as a first order process with respect to both substrate and methanotroph concentration. This elementary formalism coupled with simplified representations of advection and …
Greenland’S Island Rule And The Arctic Ocean Circulation, Terrence M. Joyce, Andrey Proshutinsky
Greenland’S Island Rule And The Arctic Ocean Circulation, Terrence M. Joyce, Andrey Proshutinsky
Journal of Marine Research
In order to explain observed southward water transport of 2-3 Sv through Davis Strait, a simple extension of Godfrey's (1989) Island Rule and a 2-D idealized numerical model simulations were made for the flow around Greenland. Godfrey's theory has been extended to permit inclusion of Bering Strait inflow and bottom friction to represent the dissipation supplied by the porous Canadian Archipelago in the modeled flow west of Greenland. In both models, the forcing has been applied in a quasi-steady manner to the circulation via climatologic wind stresses and using wind forcing for the high and low Arctic Oscillation (AO) index …
Effects Of Environmental Factors On The Paternal Brood Pouch And Sound Production In Two Sympatric Pipefish Species From The Chincoteague Bay, Virginia, Jennifer L. Ripley
Effects Of Environmental Factors On The Paternal Brood Pouch And Sound Production In Two Sympatric Pipefish Species From The Chincoteague Bay, Virginia, Jennifer L. Ripley
Graduate Theses, Dissertations, and Problem Reports (ETD)
Pipefishes and seahorses of the family Syngnathidae are important inhabitants of diminishing grass beds threatened by excessive nutrient loads, sedimentation, and chemical contaminants. This research examined the influence of these environmental factors on two sympatric pipefishes from the Chincoteague Bay, Virginia. Syngnathids are characterized by a unique mode of reproduction in which the male carries developing embryos in a placenta-like ventral brood pouch until the fry are free-swimming. Interspecific comparisons revealed differences in parental nutrient allocation to embryos. In Syngnathus fuscus, females produce nutritionally poor eggs and males implant developing embryos adjacent to blood vessels. The loose connection between eggs …
Health Assessment In The Bowhead Whale, Cheryl Rosa
Health Assessment In The Bowhead Whale, Cheryl Rosa
Biological Sciences
Tissue samples and morphometric data were collected from 64 bowhead whales landed during the 1998-2002 subsistence hunts in Barrow and Kaktovik, Alaska. Our primary goal was to assess the health status of the Bering-Chukchi-Beaufort Seas stock of bowhead whales. Ages of whales were determined via aspartic acid racemization of the eye lens nucleus, baleen stable carbon isotope analysis and morphometric and histologic indices. We investigated the gross and microscopic anatomy of organs and blubber, thyroid hormone concentrations, serum haptoglobin, vitamin A and E concentrations in liver, blubber and serum and essential element concentrations in liver and kidney. Thyroid hormone and …
Retrospective Analysis Of Marine Biological Data From Port Valdez, Alaska: A Case Study In Long -Term Monitoring, Arny L. Blanchard
Retrospective Analysis Of Marine Biological Data From Port Valdez, Alaska: A Case Study In Long -Term Monitoring, Arny L. Blanchard
Marine Biology
Efforts to understand anthropogenic effects within the Port Valdez study area provide a simple and adaptive model for developing and refining hypotheses to measure the structure of and detect, change in nearshore and benthic habitats. Drivers of change detected by this study are the 1964 Prince William Sound earthquake and the oil transportation and salmon aquaculture industries within the fjord. The study area is a glacial-outwash fjord characterized by strong seasonal and spatial environmental gradients due to glacial influences including seasonally low salinity, high suspended sediment loads, and subsequent high sedimentation rates. Direct and indirect effects from intolerance to low …
Growth Rates Of Calanoid Copepods In The Northern Gulf Of Alaska, And Their Relationships To Temperature, Chlorophyll And Body Size, Hui Liu
Marine Biology
The juvenile growth rate and development time of the dominant calanoid copepods in the northern Gulf of Alaska were investigated. The utility of the artificial-cohort method was successfully validated as the most practical approach for estimating copepod growth rates in this ecosystem. The underlying functional responses of growth rates to temperature, food concentration, and body size were thoroughly explored for Neocalanus flemingeri/plumchrus, Metridia pacifica, Calanus marshallae, C. pacificus and Pseudocalanus spp. These results lay the foundation for the calculation of copepod secondary production and ongoing ecosystem modeling activities for the northern Gulf of Alaska, and will contribute to the refinement …
A Multiple Stable Isotope Study Of Steller Sea Lions And Bowhead Whales: Signals Of A Changing Northern Environment, Pieter Andrew Dehart
A Multiple Stable Isotope Study Of Steller Sea Lions And Bowhead Whales: Signals Of A Changing Northern Environment, Pieter Andrew Dehart
Marine Biology
The North Pacific and Arctic marine realm is currently experiencing dramatic environmental changes as a result of global climate change. Stable isotope analysis of western arctic bowhead whales (WABW, Balaena mysticetus ) and Steller sea lions (SSL, Eumetopias jubatus) were conducted to examine the influence of these changes on life history characteristics (migration and foraging) of these marine mammals. WABW baleen plates were analyzed for their stable oxygen and hydrogen isotope composition (delta 18O and deltaD) and were compared to the delta18O and deltaD in water and zooplankton prey along their seasonal migratory route. The delta18O and deltaD varied along …
Population Structure And Behavior Of Pacific Halibut, Andrew C. Seitz
Population Structure And Behavior Of Pacific Halibut, Andrew C. Seitz
Marine Biology
Pacific halibut (Hippoglossus stenolepis) is not managed on regional scales with separate population dynamics, but rather as a single, fully mixed population extending from California through the Bering Sea. However, some of the evidence from which this paradigm was established is questionable and I hypothesize that there are separate spawning populations of Pacific halibut in three regions, the Gulf of Alaska, Bering Sea and Aleutian Islands, because these regions are geographically separated by land masses and/or deep water passes that may prevent movement by adults. Pop-up Archival Transmitting (PAT) tags were attached to Pacific halibut in each region to examine …