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Articles 661 - 690 of 855

Full-Text Articles in Marine Biology

Nitrogen Fixation And Release Of Fixed Nitrogen By Trichodesmium Spp. In The Gulf Of Mexico, Margaret R. Mulholland, Peter W. Bernhardt, Cynthia A. Heil, Deborah A. Bronk, Judith M. O'Neil Jan 2006

Nitrogen Fixation And Release Of Fixed Nitrogen By Trichodesmium Spp. In The Gulf Of Mexico, Margaret R. Mulholland, Peter W. Bernhardt, Cynthia A. Heil, Deborah A. Bronk, Judith M. O'Neil

OES Faculty Publications

During a 3-yr study in the Gulf of Mexico, we measured dinitrogen (N2) fixation and nitrogen (N) release by Trichodesmium and compared these rates with water column N demand and the estimated N necessary to support blooms of Karenia brevis, a toxic dinoflagellate that severely affects the West Florida shelf. Net and gross N2 fixation rates were compared in simultaneous incubations using 15N2 uptake and acetylene reduction, respectively. The difference between net and gross N2 fixation is assumed to be an approximation of the rate of N release. Results demonstrate that Trichodesmium in …


The Role Of Lipids During Embryonic Development Of The Euphausiids Euphausia Pacifica And Thysanoessa Spinifera, Se-Jong Ju, H. Rodger Harvey, Jaime Gómez-Gutiérrez, William T. Peterson Jan 2006

The Role Of Lipids During Embryonic Development Of The Euphausiids Euphausia Pacifica And Thysanoessa Spinifera, Se-Jong Ju, H. Rodger Harvey, Jaime Gómez-Gutiérrez, William T. Peterson

OES Faculty Publications

To understand the role of lipids during early embryogenesis, major lipid classes together with individual fatty acid and sterol composition were determined in embryos from multiple developmental stages of the euphausiids Euphausia pacifica and Thysanoessa spinifera. Average lipid content in embryos of E. pacifica and T. spiniferafrom the earliest stage (multicell) were 4.45 and 3.69 µg embryo-1,respectively. During development, the lipid content decreased at similar rates in the embryos of both species. In contrast to many crustacean eggs, phospholipids were the dominant lipid class in all embryonic stages, with decreasing concentrations seen during development. Individual …


Distribution Of Foraging Shearwaters Relative To Inner Front Of Se Bering Sea, J. Jahncke, K. O. Coyle, Stephan I. Zeeman, N. B. Kachel, G. L. Hunt Jr. Dec 2005

Distribution Of Foraging Shearwaters Relative To Inner Front Of Se Bering Sea, J. Jahncke, K. O. Coyle, Stephan I. Zeeman, N. B. Kachel, G. L. Hunt Jr.

Marine Sciences Faculty Publications

We examined the hypothesis that short-tailed shearwaters Puffinus tenuirostris aggregate to forage at the inner front of the SE Bering Sea because of enhanced production there. We tested this hypothesis by comparing primary production, the distribution of euphausiids and the distribution of shearwaters relative to the front during late spring and late summer/early fall of 1997, 1998 and 1999. We found enhanced primary production at the front and offshore of the front during summer but not during spring. Primary production varied between seasons and years. Major differences were related to anomalous conditions in 1997 and 1998. The density of euphausiids …


Estimation Of Iron Solubility From Observations And A Global Aerosol Model, Chao Luo, N. M. Mahowald, N. Meskhidze, Y. Chen, R. L. Siefert, A. R. Baker, Anne M. Johansen Dec 2005

Estimation Of Iron Solubility From Observations And A Global Aerosol Model, Chao Luo, N. M. Mahowald, N. Meskhidze, Y. Chen, R. L. Siefert, A. R. Baker, Anne M. Johansen

All Faculty Scholarship for the College of the Sciences

Mineral aerosol deposition is the dominant source of iron to the open ocean. Soil iron is typically insoluble and understanding the atmospheric processes that convert insoluble iron to the more soluble forms observed over the oceans is crucial. In this paper, we model several proposed processes for the conversion of Fe(III) to Fe(II), and compare with cruise observations. The comparisons show that the model results in similar averaged magnitudes of iron solubility as measured during 8 cruises in 2001–2003. Comparisons show that results of cases including cloud, SO2 and hematite processing are better than the other approaches used using …


Fall 2005, Nsu Oceanographic Center Oct 2005

Fall 2005, Nsu Oceanographic Center

Currents

No abstract provided.


Characterization Of Pfiesteria Ichthyocidal Activity, Andrew S. Gordon, Harold G. Marshall, Sandra E. Shumway, Kathryn J. Coyne, Alan J. Lewitus, Michael A. Mallin, Parke A. Rublee Oct 2005

Characterization Of Pfiesteria Ichthyocidal Activity, Andrew S. Gordon, Harold G. Marshall, Sandra E. Shumway, Kathryn J. Coyne, Alan J. Lewitus, Michael A. Mallin, Parke A. Rublee

Biological Sciences Faculty Publications

Letter to the Editor regarding article: Drgon, T., et al. 2005. Characterization of ichthyocidal activity of Pfiesteria piscicida: Dependence on the dinospore cell density. Appl. Environ. Microbiol. 71:519–529


Summer 2005, Nsu Oceanographic Center Aug 2005

Summer 2005, Nsu Oceanographic Center

Currents

No abstract provided.


Spring 2005, Nsu Oceanographic Center Apr 2005

Spring 2005, Nsu Oceanographic Center

Currents

No abstract provided.


Winter 2005, Nsu Oceanographic Center Jan 2005

Winter 2005, Nsu Oceanographic Center

Currents

No abstract provided.


Demonstration Of Toxicity To Fish And To Mammalian Cells By Pfiesteria Species: Comparison Of Assay Methods And Strains, Joann M. Burkholder, Andrew S. Gordon, Peter D. Moeller, J. Mac Law, Kathryn J. Coyne, Alan J. Lewitus, John S. Ramsdell, Harold G. Marshall, Nora J. Deamer, S. Craig Cary, Jason W. Kempton, Steven L. Morton, Parke A. Rublee Jan 2005

Demonstration Of Toxicity To Fish And To Mammalian Cells By Pfiesteria Species: Comparison Of Assay Methods And Strains, Joann M. Burkholder, Andrew S. Gordon, Peter D. Moeller, J. Mac Law, Kathryn J. Coyne, Alan J. Lewitus, John S. Ramsdell, Harold G. Marshall, Nora J. Deamer, S. Craig Cary, Jason W. Kempton, Steven L. Morton, Parke A. Rublee

Biological Sciences Faculty Publications

Toxicity and its detection in the dinoflagellate fish predators Pfiesteria piscicida and Pfiesteria shumwayae depend on the strain and the use of reliable assays. Two assays, standardized fish bioassays (SFBs) with juvenile fish and fish microassays (FMAs) with larval fish, were compared for their utility to detect toxic Pfiesteria. The comparison included strains with confirmed toxicity, negative controls (noninducible Pfiesteria strains and a related nontoxic cryptoperidiniopsoid dinoflagellate), and P. shumwayae strain CCMP2089, which previously had been reported as nontoxic. SFBs, standardized by using toxic Pfiesteria (coupled with tests confirming Pfiesteria toxin) and conditions conducive to toxicity expression, reliably detected …


A Review Of Phytoplankton Composition Within Chesapeake Bay And Its Tidal Estuaries, Harold G. Marshall, Lubomira Burchardt, Richard Lacouture Jan 2005

A Review Of Phytoplankton Composition Within Chesapeake Bay And Its Tidal Estuaries, Harold G. Marshall, Lubomira Burchardt, Richard Lacouture

Biological Sciences Faculty Publications

Based on a continuous 20-year data base ofmonthly sampling in Chesapeake Bay and tidal regions of its major tributaries, 1454 phytoplankton taxa have been identified in these waters. They represent a diverse assemblage of species with a dominant diatom flora throughout the year, in addition to large seasonal representation by chlorophytes, cyanobacteria, cryptophytes and dinoflagellates. Included among this flora were 34 potential harmful or toxin producing species. The phytoplankton compositions associated with the seasonal successional patterns are discussed, in addition to characterizing the dominant floral relationships, with comparison to early composition records within the Bay. Several of the present day …


Can Otolith Elemental Signatures Record The Capture Site Of Patagonian Toothfish (Dissostichus Eleginoides), A Fully Marine Fish In The Southern Ocean?, J. R. Ashford, C. M. Jones, E. Hofmann, I. Everson, C. Moreno, G. Duhamel, R. Williams Jan 2005

Can Otolith Elemental Signatures Record The Capture Site Of Patagonian Toothfish (Dissostichus Eleginoides), A Fully Marine Fish In The Southern Ocean?, J. R. Ashford, C. M. Jones, E. Hofmann, I. Everson, C. Moreno, G. Duhamel, R. Williams

CCPO Publications

Otolith chemistry has been successfully used to reconstruct the environmental history experienced by estuarine-dependent teleost fish, including movement between estuaries and coastal areas. However, application has been more limited in species exposed exclusively to oceanic waters, where gradients in physical and chemical properties are less extreme. To test whether otolith elemental signatures record spatial information in an oceanic species, we sampled otoliths from Patagonian toothfish (Dissostichus eleginoides) and used an inductively coupled plasma mass spectrometer (ICP-MS) coupled to a laser ablation system to target the outer otolith edges corresponding to the period immediately before capture. Using multivariate analysis …


The Role Of Feeding Behavior In Sustaining Copepod Populations In The Tropical Ocean, J. D. Wiggert, A. G. E. Haskell, G.-A. Paffenhofer, E. E. Hofmann, J. M. Klinck Jan 2005

The Role Of Feeding Behavior In Sustaining Copepod Populations In The Tropical Ocean, J. D. Wiggert, A. G. E. Haskell, G.-A. Paffenhofer, E. E. Hofmann, J. M. Klinck

CCPO Publications

A fundamental question regarding marine copepods is how the many species coexist and persist in the oligotrophic environment (i.e. Hutchinson’s paradox). This question is addressed with a stochastic, object-oriented Lagrangian model that explicitly simulates the distinct foraging behaviors of three prominent tropical species: Clausocalanus furcatus, Paracalanus aculeatus and Oithona plumifera. The model also individually tracks all prey cells. Each particle’s motion combines sinking, turbulent diffusion and active swimming when applicable. The model successfully simulates observed size partitioned carbon uptake rates. Based on the model results, the wide-ranging translational ambit employed by C. furcatus is best suited for the acquisition …


Feeding Ecology Of Juvenile Spiny Lobster, Panulirus Interruptus, On The Pacific Coast Of Baja California Sur, Mexico, Verónica Castañeda‐Fernández‐De‐Lara, Elisa Serviere‐Zaragoza, Sergio Hernández‐Vázquez, Mark J. Butler Iv Jan 2005

Feeding Ecology Of Juvenile Spiny Lobster, Panulirus Interruptus, On The Pacific Coast Of Baja California Sur, Mexico, Verónica Castañeda‐Fernández‐De‐Lara, Elisa Serviere‐Zaragoza, Sergio Hernández‐Vázquez, Mark J. Butler Iv

Biological Sciences Faculty Publications

Many aspects of the early life history of the red lobster Panulirus interruptus are little known, including the relationship between habitat structure, food resource availability, and nutrition of juveniles. We investigated the spatial and temporal differences in food intake, diet composition, and nutritional condition of juveniles at two sites along the Pacific coast of the Baja California Peninsula (Mexico) with contrasting oceanographic and biological conditions. One site (Arvin) is located inside a protected bay, Bahia Tortugas, where the waters are cooler and temperate seagrasses and macroalgae are the dominant benthic flora. The second site (Queen) in Bahia Sebastian Vizcaino was …


Iron In The Sargasso Sea (Bermuda Atlantic Time-Series Study Region) During Summer: Eolian Imprint, Spatiotemporal Variability, And Ecological Implications, Peter N. Sedwick, T. M. Church, A. R. Bowie, C. M. Marsay, S. J. Ussher, K. M. Achilles, P. J. Lethaby, R. J. Johnson, M. M. Sarin, D. J. Mcgillicuddy Jan 2005

Iron In The Sargasso Sea (Bermuda Atlantic Time-Series Study Region) During Summer: Eolian Imprint, Spatiotemporal Variability, And Ecological Implications, Peter N. Sedwick, T. M. Church, A. R. Bowie, C. M. Marsay, S. J. Ussher, K. M. Achilles, P. J. Lethaby, R. J. Johnson, M. M. Sarin, D. J. Mcgillicuddy

OES Faculty Publications

We report iron measurements for water column and aerosol samples collected in the Sargasso Sea during July-August 2003 (summer 2003) and April-May 2004 (spring 2004). Our data reveal a large seasonal change in the dissolved iron (dFe) concentration of surface waters in the Bermuda Atlantic Time-series Study region, from ∼1-2nM in summer 2003, when aerosol iron concentrations were high (mean 10 nmol/m-3), to ∼0.1-0.2nM in spring 2004, when aerosol iron concentrations were low (mean 0.64 nmol/m-3). During summer 2003, we observed an increase of ∼0.6nM in surface water dFe concentrations over 13 days, presumably due to …


A Unique Seasonal Pattern In Phytoplankton Biomass In Low-Latitude Waters In The South China Sea, Chun-Mao Tseng, George T. F. Wong, I.-I. Lin, C.-R. Wu, K.-K. Liu Jan 2005

A Unique Seasonal Pattern In Phytoplankton Biomass In Low-Latitude Waters In The South China Sea, Chun-Mao Tseng, George T. F. Wong, I.-I. Lin, C.-R. Wu, K.-K. Liu

OES Faculty Publications

A distinctive seasonal pattern in phytoplankton biomass was observed at the South East Asian Time series Study (SEATS) station (18°N, 116°E) in the northern South China Sea (SCS). Surface chlorophyll-a, depth integrated chlorophyll-a and primary production were elevated to 0.3 mg/m3, ~35 mg/m2 and 300 mg-C/m2/d, respectively, in the winter but stayed low, at 0.1 mg/m3, ~15 mg/m2 and 110 mg-C/m2/d as commonly found in other low latitude waters, in the rest of the year. Concomitantly, soluble reactive phosphate and nitrate+nitrite in the mixed layer also became …


The Effect Of Growth Rate, Phosphorus Concentration, And Temperature On N-2 Fixation, Carbon Fixation, And Nitrogen Release In Continuous Cultures Of Trichodesmium Ims101, Margaret R. Mulholland, Peter W. Bernhardt Jan 2005

The Effect Of Growth Rate, Phosphorus Concentration, And Temperature On N-2 Fixation, Carbon Fixation, And Nitrogen Release In Continuous Cultures Of Trichodesmium Ims101, Margaret R. Mulholland, Peter W. Bernhardt

OES Faculty Publications

With the use of continuous culture systems, rates of dinitrogen (N2) and carbon (C) fixation and nitrogen (N)- and C-based doubling times were assessed in Trichodesmium IMS101 growing exponentially at steady state dilution rates of 0.10, 0.20, and 0.33 d-1 (doubling times of 10, 5, and 3 d - within the range reported for natural populations). Rates of C fixation, N2 fixation, and N release were examined in replicate culture systems with several techniques. Biomass-specific C uptake varied little with population doubling time, but N2 fixation and N release varied markedly among treatments. Total daily …


Do Viruses Affect Fecundity And Survival Of The Copepod Acartia Tonsa Dana?, Lisa A. Drake, Fred C. Dobbs Jan 2005

Do Viruses Affect Fecundity And Survival Of The Copepod Acartia Tonsa Dana?, Lisa A. Drake, Fred C. Dobbs

OES Faculty Publications

Naturally occurring viruses are extremely abundant in aquatic systems, and they infect bacteria, cyanobacteria, prokaryotic and eukaryotic phytoplankton, heterotrophic nanoflagellates, fish and mammals. Viral infections of single-celled organisms have been studied intensively in the past decade, but little is known about the effects of viruses on aquatic metazoans, other than for some economically important species. Because zooplankton assemblages are often dominated in number and biomass by copepods, we used them as model organisms to study the effects of naturally occurring viruses on higher trophic levels. We attempted to induce viral infection in laboratory-reared cultures of the estuarine copepod Acartia tonsa …


Biophysical Mechanisms Of Larval Fish Ingress Into Chesapeake Bay, Jonathan A. Hare, Simon Thorrold, Harvey Walsh, Christian Reiss, Arnoldo Valle-Levinson, Cynthia Jones Jan 2005

Biophysical Mechanisms Of Larval Fish Ingress Into Chesapeake Bay, Jonathan A. Hare, Simon Thorrold, Harvey Walsh, Christian Reiss, Arnoldo Valle-Levinson, Cynthia Jones

OES Faculty Publications

Selective tidal stream transport is hypothesized as a dominant mechanism by which larvae of marine animals move through estuarine openings. For larvae moving from the shelf to estuarine habitats, selective tidal stream transport proposes that larvae are higher in the water column during flood tide and lower in the water column during ebb tide. Although a number of studies conclude that selective tidal stream transport is the mechanism responsible for larval ingress, few studies consider alternative mechanisms or consider passive explanations for tidal patterns in larval distributions. We examined the biophysical mechanisms responsible for larval ingress into Chesapeake Bay using …


Fall 2004, Nsu Oceanographic Center Oct 2004

Fall 2004, Nsu Oceanographic Center

Currents

No abstract provided.


A Physiochemically Constrained Seawater Culturing System For Production Of Benthic Foraminifera, Christopher J. Hintz, G. Thomas Chandler, Jay M. Bernhardt, Daniel C. Mccorkle, Suzanne M. Havach, Jessica K. Blanks, Timothy J. Shaw Jun 2004

A Physiochemically Constrained Seawater Culturing System For Production Of Benthic Foraminifera, Christopher J. Hintz, G. Thomas Chandler, Jay M. Bernhardt, Daniel C. Mccorkle, Suzanne M. Havach, Jessica K. Blanks, Timothy J. Shaw

Faculty Publications

No abstract provided.


Spring 2004, Nsu Oceanographic Center Apr 2004

Spring 2004, Nsu Oceanographic Center

Currents

No abstract provided.


Relating Water And Otolith Chemistry In Chesapeake Bay, And Their Potential To Identify Essential Seagrass Habitats For Juveniles Of An Estuarine-Dependent Fish, Spotted Seatrout (Cynoscion Nebulosus), Emmanis Dorval Apr 2004

Relating Water And Otolith Chemistry In Chesapeake Bay, And Their Potential To Identify Essential Seagrass Habitats For Juveniles Of An Estuarine-Dependent Fish, Spotted Seatrout (Cynoscion Nebulosus), Emmanis Dorval

Biological Sciences Theses & Dissertations

A quantitative understanding of habitat use of estuarine-dependent fishes is critical to the conservation of their most essential habitats. Because recruitment and fitness may be influenced by the quality of juvenile habitats, developing methods to quantify habitat-specific survivorship is pivotal to such understanding. An initial step to quantify survivorship is to validate the habitat-specific natural tags contained in otoliths. To this aim I investigated the variability in the chemistry of surface waters and otoliths of juvenile spotted seatrout, Cynoscion nebulosus, in five seagrass habitats of Chesapeake Bay, namely: Potomac, Rappahannock, York, Island, and Eastern Shore. I measured Mg, Ca, …


Winter 2004, Nsu Oceanographic Center Jan 2004

Winter 2004, Nsu Oceanographic Center

Currents

No abstract provided.


Summer 2004, Nova Southeastern University Jan 2004

Summer 2004, Nova Southeastern University

Currents

No abstract provided.


A Modelling Study Of The Influence Of Environment And Food Supply On Survival Of Crassostrea Gigas Larvae, Eileen E. Hofmann, Eric N. Powell, Eleanor A. Bochenek, John M. Klinck Jan 2004

A Modelling Study Of The Influence Of Environment And Food Supply On Survival Of Crassostrea Gigas Larvae, Eileen E. Hofmann, Eric N. Powell, Eleanor A. Bochenek, John M. Klinck

CCPO Publications

A biochemically based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster (Crassostrea gigas). The unique characteristics of the model are that it: (1) defines larvae in terms of their protein, neutral lipid, polar lipid, carbohydrate, and ash content; (2) tracks weight separately from length to follow larval condition; and (3) includes genetic variation in growth efficiency and egg quality to better simulate cohort population dynamics. The model includes parameterizations for filtration, ingestion, and respiration, which determine larval growth rate, and processes controlling larval mortality and metamorphosis. Changes in larval tissue …


Lagrangian Modelling Studies Of Antarctic Krill (Euphausia Superba) Swarm Formation, Eileen E. Hofmann, A. G. Edward Haskell, John M. Klinck, Cathy M. Lascara Jan 2004

Lagrangian Modelling Studies Of Antarctic Krill (Euphausia Superba) Swarm Formation, Eileen E. Hofmann, A. G. Edward Haskell, John M. Klinck, Cathy M. Lascara

CCPO Publications

A two-dimensional Lagrangian particle model was developed to examine the spatial distribution of Antarctic krill (Euphausia superba). The time-dependent location of particles, which represent krill individuals, is determined by random diffusion, foraging activity, and movement induced by the presence of neighbours. Foraging activity is based on prescribed food conditions and is such that krill swim slower and turn more frequently in areas of high food concentration. The presence or absence of neighbours either disperses krill, if the local concentrations become too dense, or coalesces krill, if concentrations become too dilute, respectively. Predation on krill is included and affects …


Interactive Regulation Of Dissolved Copper Toxicity By An Estuarine Microbial Community, Christina L. Dryden, Andrew S. Gordon, John R. Donat Jan 2004

Interactive Regulation Of Dissolved Copper Toxicity By An Estuarine Microbial Community, Christina L. Dryden, Andrew S. Gordon, John R. Donat

OES Faculty Publications

Cultured marine microorganisms under copper stress produce extracellular compounds having a high affinity for copper (copper-complexing ligands). These ligands are similar in binding strength to those found in natural waters, but few studies have examined the relationship between copper, copper-complexing ligand concentrations, and natural microbial populations. A series of in situ experiments in the Elizabeth River, Virginia, revealed that an intact estuarine microbial community responded to copper stress by production of extracellular, high-affinity copper-complexing ligands. The rate of ligand production was dependent on copper concentration and resulted in a reduction of the concentration of free cupric ions, Cu2+, …


Advection, Krill, And Antarctic Marine Ecosystems, Eileen E. Hofmann, Eugene J. Murphy Jan 2004

Advection, Krill, And Antarctic Marine Ecosystems, Eileen E. Hofmann, Eugene J. Murphy

CCPO Publications

Advective processes are recognized as being important in structuring and maintaining marine ecosystems. In the Southern Ocean advective effects are perhaps most clearly observed because the Antarctic Circumpolar Current (ACC) provides a connection between most parts of the system, including open ocean and continental shelf regions. The ACC also provides a mechanism for large-scale transport of plankton, such as Antarctic krill (Euphousia superba Dana), which is an important component of the Southern Ocean food web. This overview provides a summary of recent observational and modelling results that consider the importance of advection to the Southern Ocean ecosystem and, in particular, …


Influence Of Short-Term Variations In Food On Survival Of Crassotrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A, Bochenek, John M. Klinck, Eileen E. Hofmann Jan 2004

Influence Of Short-Term Variations In Food On Survival Of Crassotrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A, Bochenek, John M. Klinck, Eileen E. Hofmann

OES Faculty Publications

A biochemically-based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster, Crassostrea gigas. The model defines larvae in terms of their protein, lipid, carbohydrate, and ash content and includes variation in growth efficiency and egg quality to better simulate cohort population dynamics. Changes in tissue composition occur as the larva grows and in response to the biochemical composition of the food. The premise behind this modeling study was that certain periods of larval life are more critical than others with respect to the availability of food and that food quality is as …