Open Access. Powered by Scholars. Published by Universities.®

Marine Biology

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 631 - 660 of 852

Full-Text Articles in Oceanography

Otolith Chemistry Indicates Population Structuring By The Antarctic Circumpolar Current, Julian R. Ashford, Cynthia M. Jones, Eileen E. Hofmann, Inigo Everson, Carlos A. Moreno, Guy Duhamel, Richard Williams Jan 2008

Otolith Chemistry Indicates Population Structuring By The Antarctic Circumpolar Current, Julian R. Ashford, Cynthia M. Jones, Eileen E. Hofmann, Inigo Everson, Carlos A. Moreno, Guy Duhamel, Richard Williams

CCPO Publications

Large-scale transport of seawater in ocean currents may generate spatially complex population structure through the advection of life stages of marine fish species. To test this, we compared the chemistry of otolith nuclei from Patagonian toothfish (Dissostichus eleginoides), presently managed as spatially discrete Populations corresponding to fishing management areas along the Antarctic Circumpolar Current (ACC), which transports water eastward around the Southern Ocean. The chemistry of otolith nuclei, laid down during early life, differed significantly between fishing areas Off South America and the Antarctic and between some Antarctic areas. However, we found significant discrepancies from expectation for a …


Absorption Spectral Slopes And Slope Ratios As Indicators Of Molecular Weight, Source, And Photobleaching Of Chromophoric Dissolved Organic Matter, John R. Helms, Aron Stubbins, Jason D. Ritchie, Elizabeth C. Minor, David J. Kieber, Kenneth Mopper Jan 2008

Absorption Spectral Slopes And Slope Ratios As Indicators Of Molecular Weight, Source, And Photobleaching Of Chromophoric Dissolved Organic Matter, John R. Helms, Aron Stubbins, Jason D. Ritchie, Elizabeth C. Minor, David J. Kieber, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

A new approach for parameterizing dissolved organic matter ( DOM) ultraviolet-visible absorption spectra is presented. Two distinct spectral slope regions ( 275-295 nm and 350-400 nm) within log-transformed absorption spectra were used to compare DOM from contrasting water types, ranging from wetlands (Great Dismal Swamp and Suwannee River) to photobleached oceanic water ( Atlantic Ocean). On the basis of DOM size-fractionation studies ( ultrafiltration and gel filtration chromatography), the slope of the 275-295- nm region and the ratio of these slopes (SR; 275-295- nm slope : 350-400- nm slope) were related to DOM molecular weight ( MW) and …


Limb Regeneration After Multiple Autotomy And Coxae Removal In The Blue Crab Callinectes Sapidus, Jennifer Ambler Oct 2007

Limb Regeneration After Multiple Autotomy And Coxae Removal In The Blue Crab Callinectes Sapidus, Jennifer Ambler

OES Theses and Dissertations

This study investigated limb regeneration in the juvenile blue crab, Callinectes sapidus, specifically the role of the coxa and pedal nerve innervation of the regenerative limb bud over time. The coxa is a leg segment that has been defined as the source of positional, cellular, and neuronal information needed for limb regeneration in brachyuran crabs. This study indicates that removal of coxae under regenerative and non-regenerative conditions did not deter limb regeneration. The coxa is not the exclusive location of limb regenerative information since limbs re-grew with normal positional and functional arrangement in 86% of crabs showing regeneration at removal …


Summer/Fall 2007, Nsu Oceanographic Center Sep 2007

Summer/Fall 2007, Nsu Oceanographic Center

Currents

No abstract provided.


Spring 2007, Nsu Oceanographic Center Apr 2007

Spring 2007, Nsu Oceanographic Center

Currents

No abstract provided.


Interactions Between Phytoplankton And Bacteria In The Uptake Of Organic Compounds, Andrea Michel Rocha Apr 2007

Interactions Between Phytoplankton And Bacteria In The Uptake Of Organic Compounds, Andrea Michel Rocha

OES Theses and Dissertations

The most common methods for estimating bacterial productivity are [3H]-leucine and [3H]-thymidine incorporation. Uptake of these compounds has been attributed primarily to bacteria; however, because dissolved organic nitrogen may be an important N source for some phytoplankton, the use of these compounds to estimate bacterial productivity needs to be reexamined. In order to ascertain whether phytoplankton could compete with bacteria on relevant timescales and thereby bias bacterial productivity estimates in estuaries, I examined the ability of cultured phytoplankton and size-fractionated natural populations to take up leucine and thymidine in systems seasonally dominated by phytoplankton mixotrophs. In …


Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 1. Model Configuration And Ecosystem Dynamics, Baris Salihoglu, Eileen E. Hofmann Jan 2007

Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 1. Model Configuration And Ecosystem Dynamics, Baris Salihoglu, Eileen E. Hofmann

OES Faculty Publications

The primary objective of this research is to investigate phytoplankton community response to variations in physical forcing and biological processes in the Cold Tongue region of the equatorial Pacific Ocean at 0N, 140W. This research objective was addressed using a one-dimensional multicomponent lower trophic level ecosystem model that includes detailed algal physiology, such as spectrally-dependent photosynthetic processes and iron limitation on algal growth. The ecosystem model is forced by a one-year (1992) time series of spectrally-dependent light, temperature, and water column mixing obtained from a Tropical Atmosphere-Ocean (TAO) Array mooring. Autotrophic growth is represented by five algal groups, which have …


Co2 Control Of Trichodesmium N-2 Fixation, Photosynthesis, Growth Rates, And Elemental Ratios: Implications For Past, Present, And Future Ocean Biogeochemistry, D. A. Hutchins, F.-X. Fu, Y. Zhang, M. E. Warner, Y. Feng, K. Portune, P. W. Bernhardt, M. R. Mulholland Jan 2007

Co2 Control Of Trichodesmium N-2 Fixation, Photosynthesis, Growth Rates, And Elemental Ratios: Implications For Past, Present, And Future Ocean Biogeochemistry, D. A. Hutchins, F.-X. Fu, Y. Zhang, M. E. Warner, Y. Feng, K. Portune, P. W. Bernhardt, M. R. Mulholland

OES Faculty Publications

Diazotrophic marine cyanobacteria in the genus Trichodesmium contribute a large fraction of the new nitrogen entering the oligotrophic oceans, but little is known about how they respond to shifts in global change variables such as carbon dioxide (CO2) and temperature. We compared Trichodesmium dinitrogen (N2) and CO2 fixation rates during steady-state growth under past, current, and future CO2 scenarios, and at two relevant temperatures. At projected CO2 levels of year 2100 (76 Pa, 750 ppm), N2 fixation rates of Pacific and Atlantic isolates increased 35-100%, and CO2 fixation rates increased 15-128% …


Otolith Chemistry Reflects Frontal Systems In The Antarctic Circumpolar Current, J. R. Ashford, A. I. Arkhipkin, C. M. Jones Jan 2007

Otolith Chemistry Reflects Frontal Systems In The Antarctic Circumpolar Current, J. R. Ashford, A. I. Arkhipkin, C. M. Jones

OES Faculty Publications

Pronounced environmental trends across fronts suggest that the otolith chemistry of oceanic fish can resolve zones on either side, promoting application to population questions at similar spatial scales. Trace and minor elements laid down immediately prior to capture - along the edges of otoliths from Patagonian toothfish Dissostichus eleginoides - discriminated frontal zones in the Antarctic Circumpolar Current in the Southwestern Atlantic Ocean. Mean values differentiated sampling areas by up to 2.6 standard deviations, suggesting: (1) otolith Mg/Ca enrichment related to fish activity around the Burdwood Bank; (2) Mn/Ca enrichment associated with South America; (3) Sr/Ca linked to the presence …


Grazing Impacts Of Diverse Zooplankton Taxa On Thin Layers, Alexander Bochdansky Jan 2007

Grazing Impacts Of Diverse Zooplankton Taxa On Thin Layers, Alexander Bochdansky

OES Faculty Publications

The US Navy needs to know how distributions and abundances of light-scattering and sound-scattering organisms in the ocean vary in space and time, particularly in the vertical dimension. Recent field observations have shown that many biological properties may vary substantially over small e.g. centimeter scales, commonly referred to as thin layers e.g. Cowles et al. 1998, 1999, Hanson Donaghay 1998, Holliday et al. 1999, Dekshenieks et al. 2001, Alldredge et al. 2002, Rines et al. 2002. Our previous ONR-funded research has allowed us to begin to understand how zooplankton interact with thin layers and how they can take advantage of …


Inside The Rainforests Of The Sea: Coral Reefs And Their Endangerment, Roxanne Greitz Miller Jan 2007

Inside The Rainforests Of The Sea: Coral Reefs And Their Endangerment, Roxanne Greitz Miller

Education Faculty Articles and Research

This article focuses on coral reefs and their endangerment.


Winter 2007, Nsu Oceanographic Center Jan 2007

Winter 2007, Nsu Oceanographic Center

Currents

No abstract provided.


Characterization Of Β-Lactam Resistant Pandemic Serotypes Of Vibrio Cholerae Isolated From Ships' Ballast Tanks And Coastal Waters, Amanda Lynn Goodrich Oct 2006

Characterization Of Β-Lactam Resistant Pandemic Serotypes Of Vibrio Cholerae Isolated From Ships' Ballast Tanks And Coastal Waters, Amanda Lynn Goodrich

OES Theses and Dissertations

Vibrio cholerae serotypes 01 and 0139 are responsible for world-wide epidemics of cholera. These pandemic causing strains must possess genes that encode for the cholera toxin (CTX) and toxin co-regulated pili (TCP) in order to infect their hosts. In this study, 284 isolates of Vibrio cholerae from ballast and coastal waters were serotyped, with 11 % testing positive for serotype 01 and 21 % testing positive for serotype 0139. PCR assays were used to detect the presence of ctxA and tcpA genes in all positive isolates, none of which contained ctxA while 2% of the isolates contained tcpA. The 01 …


Fall 2006, Nsu Oceanographic Center Oct 2006

Fall 2006, Nsu Oceanographic Center

Currents

No abstract provided.


Summer 2006, Nsu Oceanographic Center Aug 2006

Summer 2006, Nsu Oceanographic Center

Currents

No abstract provided.


Substituting Otoliths For Chemical Analyses: Does Sagitta = Lapillus?, Nathan G. Smith, Cynthia M. Jones May 2006

Substituting Otoliths For Chemical Analyses: Does Sagitta = Lapillus?, Nathan G. Smith, Cynthia M. Jones

OES Faculty Publications

Chemical analysis of fish otoliths has become an important technique in fisheries science with widespread applications. Most research up to this point has focused predominantly on sagittal otoliths, but the underlying assumptions may also apply to lapilli. The goal of this study was to determine whether lapilli and sagittae have the same otolith chemistry and whether one can be substituted for the other for solution-based chemical analysis in wild-captured fish. We compared the stable isotope chemistry (δ13C and δ18O) of paired sagittae and lapilli of juvenile spotted seatrout Cynoscion nebulosus collected from Chesapeake Bay seagrass beds in 2002. …


Spring 2006, Nsu Oceanographic Center Apr 2006

Spring 2006, Nsu Oceanographic Center

Currents

No abstract provided.


Age Validation And Reproductive Biology Of Bluefish, Pomatomus Saltatrix, Along The East Coast Of United States, Eric Robillard Jan 2006

Age Validation And Reproductive Biology Of Bluefish, Pomatomus Saltatrix, Along The East Coast Of United States, Eric Robillard

OES Theses and Dissertations

I describe a new preparation technique that increases readability of otoliths, along with criteria for the interpretation of otolith microstructure of bluefish, Pomatomus saltatrix, collected from Florida to New York during 2001-2003 (n = 2652). I validated annulus formation in otoliths for ages 1 to 8 using marginal increment analysis and thus extended validation by four years to include the preponderance of age classes in the catch. Although otoliths are typically superior for ageing, bluefish are routinely aged with scales; thus a side-by-side comparison of otoliths versus scales is necessary before otoliths can supplant scales. When compared, precision …


Evaluating The Biogeochemical Cycle Of Selenium In San Francisco Bay Through Modeling, Shannon L. Meseck, Gregory A. Cutter Jan 2006

Evaluating The Biogeochemical Cycle Of Selenium In San Francisco Bay Through Modeling, Shannon L. Meseck, Gregory A. Cutter

OES Faculty Publications

A biogeochemical model was developed to simulate salinity, total suspended material, phytoplankton biomass, dissolved selenium concentrations (selenite, selenate, and organic selenide), and particulate selenium concentrations (selenite + selenate, elemental selenium, and organic selenide) in the San Francisco Bay estuary. Model-generated estuarine profiles of total dissolved selenium reproduced observed estuarine profiles at a confidence interval of 91- 99% for 8 different years under various environmental conditions. The model accurately reproduced the observed dissolved speciation at confidence intervals of 81-98% for selenite, 72-91% for selenate, and 60-96% for organic selenide. For particulate selenium, model-simulated estuarine profiles duplicated the observed behavior of total …


Dynamics Of Carbon Allocation In A Deep-Water Population Of The Deciduous Kelp Pleurophycus Gardeneri (Laminariales), Clare M. Dominik, Richard C. Zimmerman Jan 2006

Dynamics Of Carbon Allocation In A Deep-Water Population Of The Deciduous Kelp Pleurophycus Gardeneri (Laminariales), Clare M. Dominik, Richard C. Zimmerman

OES Faculty Publications

Pleurophycus gardneri (Laminariales) is common in the low intertidal of the Northeast Pacific, but dominates many deep (30 to 40 m) rocky reefs in central California. Seasonal dynamics of productivity and resource allocation of a deep-water population of this deciduous, stipitate kelp were studied to understand how blade abscission affects the annual carbon budget. Patterns of growth, metabolism, and carbon storage and mobilization were measured monthly for 1 yr relative to in situ light and temperature, and used to model the annual carbon budget. The resulting carbon budget was used to determine if blade abscission effectively reduced respiratory demand during …


Red And Black Tides: Quantitative Analysis Of Water-Leaving Radiance And Perceived Color For Phytoplankton, Colored Dissolved Organic Matter, And Suspended Sediments, Heidi M. Dierssen, Raphael M. Kudela, John P. Ryan, Richard C. Zimmerman Jan 2006

Red And Black Tides: Quantitative Analysis Of Water-Leaving Radiance And Perceived Color For Phytoplankton, Colored Dissolved Organic Matter, And Suspended Sediments, Heidi M. Dierssen, Raphael M. Kudela, John P. Ryan, Richard C. Zimmerman

OES Faculty Publications

Using field measurements and quantitative modeling, we demonstrate that red coloration of the sea surface is not associated with any particular group of phytoplankton and is strongly dependent on the physiology of the human visual system. Red or brown surface waters can be produced by high concentrations of most types of algae, colored dissolved organic matter, or suspended sediment. Even though light reflected by red tides commonly peaks in the yellow spectral region (570–580 nm), human color perception requires consideration of the entire spectrum of light relative to receptors within the human eye. The color shift from green to red …


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 …


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 …


Ocean Warming And Freshening In The Northern Gulf Of Alaska, Thomas C. Royer, Chester E. Grosch Jan 2006

Ocean Warming And Freshening In The Northern Gulf Of Alaska, Thomas C. Royer, Chester E. Grosch

CCPO Publications

Water column temperatures on the shelf in the northern Gulf of Alaska have increased more than 0.8 degrees C and vertical density stratification has increased since 1970 near Seward, Alaska throughout the 250 m depth. This high latitude marine system has low water temperatures, high rates of precipitation, glacial melting, high wind speeds and high rates of biological productivity. A more than 300 km alongshore shift ( locally westward) of isotherms is suggested. The observations are consistent with a conceptual ocean-atmosphere circulation model that employs coastal freshwater discharge, glacial ablation and wind forcing. Positive regional feedback mechanisms accelerate the discharge …


Transport Of Antarctic Krill (Euphausia Superba) Across The Scotia Sea. Part Ii: Krill Growth And Survival, Bettina A. Fach, Eileen E. Hofmann, Eugene J. Murphy Jan 2006

Transport Of Antarctic Krill (Euphausia Superba) Across The Scotia Sea. Part Ii: Krill Growth And Survival, Bettina A. Fach, Eileen E. Hofmann, Eugene J. Murphy

CCPO Publications

A time-dependent, size-structured, physiologically based krill growth model was used in conjunction with a circulation model to test the hypothesis that Antarctic krill (Euphausia superba) populations at South Georgia are sustained by import of individuals from upstream regions. Surface phytoplankton concentrations along the simulated drifter trajectories were extracted from historical Coastal Zone Color Scanner (CZCS) measurements and sea ice biota concentrations were calculated from sea ice concentration and extent extracted along drifter trajectories from Special Sensor Microwave/ Imager measurements. As additional food sources, a time series of heterotrophic food was constructed from historical data, and time series of …


Vertical Distribution Of Decapod Larvae In The Entrance Of An Equatorward Facing Bay Of Central Chile: Implications For Transport, Beatriz Yannicelli, Leonardo R. Castro, Arnoldo Valle-Levinson, Larry Atkinson, Dante Figueroa Jan 2006

Vertical Distribution Of Decapod Larvae In The Entrance Of An Equatorward Facing Bay Of Central Chile: Implications For Transport, Beatriz Yannicelli, Leonardo R. Castro, Arnoldo Valle-Levinson, Larry Atkinson, Dante Figueroa

CCPO Publications

Two short biophysical surveys were carried out in order to assess how the decapod crustacean larvae vertical distribution and circulation patterns in an equatorward facing embayment (Gulf of Arauco, 37° S; 73° W) influenced larval transport into and out of the Gulf. The embayment is located at the upwelling area of south central Chile and features a deep (60 m) and a shallow (25 m) pathway of communication with the adjacent coastal ocean. Profiles of zooplankton, temperature, salinity, dissolved oxygen and current velocity were measured during a 22-h period at the shallow entrance to the gulf. In addition, three zooplankton …


Effects Of Salinity Changes On The Photodegradation And Ultraviolet-Visible Absorbance Of Terrestrial Dissolved Organic Matter, E. C. Minor, J. Pothen, B. J. Dalzell, H. Abdulla, K. Mopper Jan 2006

Effects Of Salinity Changes On The Photodegradation And Ultraviolet-Visible Absorbance Of Terrestrial Dissolved Organic Matter, E. C. Minor, J. Pothen, B. J. Dalzell, H. Abdulla, K. Mopper

Chemistry & Biochemistry Faculty Publications

We performed laboratory studies to determine the effects of salinity on the photodegradation of dissolved organic matter (DOM) from the Great Dismal Swamp, Virginia, an important source of terrestrial DOM to the lower Chesapeake Bay. Samples were created by mixing Great Dismal Swamp water (ionic strength approximate to 0 mol L-1) with modified artificial seawater solutions of differing salinities while keeping the final dissolved organic carbon (DOC) concentration constant. These samples were then irradiated for 24 h in a light box providing ultraviolet (UV) light similar to that of natural sunlight. Light absorbance and DOC concentrations decreased after …


Winter 2006, Nsu Oceanographic Center Jan 2006

Winter 2006, Nsu Oceanographic Center

Currents

No abstract provided.


The Sedimentary Environment Below Earth’S Polar Ice Cap As A Microbial Habitat, David C. Smith, Stephanie Forschner-Dancause, David C. Rowley, Steven D'Hondt Jan 2006

The Sedimentary Environment Below Earth’S Polar Ice Cap As A Microbial Habitat, David C. Smith, Stephanie Forschner-Dancause, David C. Rowley, Steven D'Hondt

Graduate School of Oceanography Faculty Publications

University of Rhode Island faculty participated in drilling of the polar ice cap to study microbial diversity and adaptation to subsurface life under conditions that may mimic extraterrestrial subsurface conditions.


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 …