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2006

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Articles 31 - 50 of 50

Full-Text Articles in Oceanography

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 …

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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 …

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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 …

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Western Caribbean Sea Surface Temperatures During The Late Quaternary, Matthew W. Schmidt, Maryline J. Vautravers, Howard J. Spero Jan 2006

Western Caribbean Sea Surface Temperatures During The Late Quaternary, Matthew W. Schmidt, Maryline J. Vautravers, Howard J. Spero

OES Faculty Publications

[1] Mg/Ca ratios in the planktonic foraminifera Globigerinoides ruber from Colombian Basin core ODP 999A suggest that Caribbean sea surface temperatures ( SSTs) were from 2.1 to 2.7°C colder than the present during the last three glacial maximums. In comparison, faunal derived SSTs ( SIMMAX method) show that August SSTs in the Caribbean varied < 2° over the past 360 kyr, whereas February SSTs varied between 21.0°C and 26.5°C. Changes in the Mg/Ca-SST record contain a strong 23 kyr periodicity, suggesting the Mg/Ca-SST record reflects a warm season weighted SST average rather than an annual mean SST. Combining several dissolution indices, we identify brief periods of decreased carbonate preservation in our record and show that MIS 11 stands out as the most intensive dissolution cycle in the Caribbean over the last 460 kyr. Comparison of Caribbean SST change with a similar estimate of tropical SST variability in the western Pacific over the past 360 kyr reveals shifts in the east-west tropical SST gradient that are coeval with glacial-interglacial climate change and consistent both with a southward migration of the glacial ITCZ and with a glacial El Niño-like mode of tropical circulation.

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Past Glacial And Interglacial Conditions In The Arctic Ocean And Marginal Seas - A Review, Dennis A. Darby, Leonid Polyak, Henning A. Bauch Jan 2006

Past Glacial And Interglacial Conditions In The Arctic Ocean And Marginal Seas - A Review, Dennis A. Darby, Leonid Polyak, Henning A. Bauch

OES Faculty Publications

Past changes in the Arctic Ocean and its marginal seas have been profound, even during the last 10,000 years. Understanding these changes, such as those occurring during the transition from glacial to interglacial climates, are important for research on modern processes, because this knowledge provides a framework and unique perspective in which to view the modern physical and biological processes. This paper discusses our current understanding of past environmental change and processes relative to those currently in progress. Special emphasis is placed on the most recent transition from a glacial state to the modern interglacial conditions.

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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 …

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Inter-Annual Sea Level Variability In The Southern Gulf Of Mexico (1966-1976), David Alberto Salas-De-León, Maria Adela Monreal-Gómez, David Salas-Monreal, Mayra Lorena Riveron-Enzastiga, Norma Leticia Sánchez-Santillan Jan 2006

Inter-Annual Sea Level Variability In The Southern Gulf Of Mexico (1966-1976), David Alberto Salas-De-León, Maria Adela Monreal-Gómez, David Salas-Monreal, Mayra Lorena Riveron-Enzastiga, Norma Leticia Sánchez-Santillan

CCPO Publications

Hourly time series at seven locations throughout the southern Gulf of Mexico were used to calculate the trend and the inter-annual sea level. The sea level series from January 1966 to December 1976 were filtered using a Lanczos low pass filter to remove oscillations with periods smaller than one year. The results revealed a sea level increment of about 1.4 mm yr(-1) from 1966 to 1976 in the southern Gulf of Mexico. The monthly sea level variability obtained after the trends were removed, presented a sea level setup during winter and a sea level depression in summer attributed to seasonal …

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Evaluating The Deep-Sea Coral Acanella From Hawaii As A Paleoceanographic Archive, Geraldine Hourigan Lantier Jan 2006

Evaluating The Deep-Sea Coral Acanella From Hawaii As A Paleoceanographic Archive, Geraldine Hourigan Lantier

Geology Theses and Dissertations

Deep-sea corals have emerged as potential proxies of changing paleoceanographic properties. The utility of deep-sea corals for the purpose of interpreting paleoclimatic reconstructions is still in the discovery phase. However, long life spans, a relatively stable habitat, and unique growth geometry provide support to the growing body of research that has identified deep-sea corals as indicators of past climate and ocean properties. Two colonies of Acanella were collected from the permanent thermocline at depths between 414 and 437 m in the Makapuu Coral Bed, Oahu, HI in 1997 by submersible. Here I present results from a pilot study of the …

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Assessing The Paleoceanographic Potential Of The Coral Montipora Venosa At Fanning Atoll, Central Equatorial Pacific, Alexa Stolorow Jan 2006

Assessing The Paleoceanographic Potential Of The Coral Montipora Venosa At Fanning Atoll, Central Equatorial Pacific, Alexa Stolorow

Geology Theses and Dissertations

As interest in global climate change increases, so does the need for better and more extensive climate proxies. The central equatorial Pacific has been established as the region with the largest ENSO-related sea surface temperature (SST) and precipitation (PPT) anomalies, which are known to impact global interannual climate variability. To date, the coral genus Porites has been most commonly utilized for coral-based paleo-reconstructions of ENSO and lower frequency phenomena. However, due to questions of biological artifacts in coral, to more fully understand coral-based reconstruction, different coral genera need to be analyzed.
In this study, oxygen (δ18O) and carbon (δ13C) isotopic …

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Topographic Influence On Overflow Dynamics: Idealized Numerical Simulations And The Faroe Bank Channel Overflow, Tal Ezer Jan 2006

Topographic Influence On Overflow Dynamics: Idealized Numerical Simulations And The Faroe Bank Channel Overflow, Tal Ezer

CCPO Publications

Properties of the North Atlantic Deep Water (NADW) depend on mixing that occurs in the Denmark Strait (DS) and the Faroe Bank Channel (FBC) overflow regions. How the sill's topography in those regions may affect mixing processes and downstream variability is thus investigated using a high-resolution terrain-following ocean model. Model results agree with observations that show enhanced mixing and entrainment downstream from the sill; however, mixing seems to occur over a longer distance downstream from the FBC sill and more abruptly downstream from the DS sill. Sensitivity experiments with various FBC sill widths demonstrate that the narrow sill is responsible …

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Loop Current Warming By Hurricane Wilma, Lie-Yauw Oey, Tal Ezer, Dong-Ping Wang, S. J. Fan, Xun-Qiang Yin Jan 2006

Loop Current Warming By Hurricane Wilma, Lie-Yauw Oey, Tal Ezer, Dong-Ping Wang, S. J. Fan, Xun-Qiang Yin

CCPO Publications

Hurricanes mix and cool the upper ocean, as shown here in observations and modeling of the Caribbean Sea and the Gulf of Mexico during the passage of hurricane Wilma. Curiously, the upper ocean around the Loop Current warmed prior to Wilma's entrance into the Gulf. The major cause was increased volume and heat transports through the Yucatan Channel produced by storm-induced convergences in the northwestern Caribbean Sea. Such oceanic variability may have important impacts on hurricane predictions.

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A Comparison Of Global Estimates Of Marine Primary Production From Ocean Color, Mary-Elena Carr, Marjorie A. M. Friedrichs, Marjorie Schmeltz, Maki Noguchi Aita, David Antoine, Kevin R. Arrigo, Ichio Asanuma, Oliver Aumont, Richard Barber, Michael Behrenfeld Jan 2006

A Comparison Of Global Estimates Of Marine Primary Production From Ocean Color, Mary-Elena Carr, Marjorie A. M. Friedrichs, Marjorie Schmeltz, Maki Noguchi Aita, David Antoine, Kevin R. Arrigo, Ichio Asanuma, Oliver Aumont, Richard Barber, Michael Behrenfeld

CCPO Publications

The third primary production algorithm round robin (PPARR3) compares output from 24 models that estimate depth-integrated primary production from satellite measurements of ocean color, as well as seven general circulation models (GCMs) coupled with ecosystem or biogeochemical models. Here we compare the global primary production fields corresponding to eight months of 1998 and 1999 as estimated from common input fields of photosynthetically-available radiation (PAR), sea-surface temperature (SST), mixed-layer depth, and chlorophyll concentration. We also quantify the sensitivity of the ocean-color-based models to perturbations in their input variables. The pair-wise correlation between ocean-color models was used to cluster them into groups …

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Pelagic Functional Group Modeling: Progress, Challenges And Prospects, Raleigh R. Hood, Edward A. Laws, Robert A. Armstrong, Nicholas R. Bates, Christopher W. Brown, Craig A. Carlson, Fei Chai, Scott C. Doney, Paul G. Falkowski, Richard A. Feely, Marjorie A. M. Friedrichs Jan 2006

Pelagic Functional Group Modeling: Progress, Challenges And Prospects, Raleigh R. Hood, Edward A. Laws, Robert A. Armstrong, Nicholas R. Bates, Christopher W. Brown, Craig A. Carlson, Fei Chai, Scott C. Doney, Paul G. Falkowski, Richard A. Feely, Marjorie A. M. Friedrichs

CCPO Publications

In this paper, we review the state of the art and major challenges in current efforts to incorporate biogeochemical functional groups into models that can be applied on basin-wide and global scales, with an emphasis on models that might ultimately be used to predict how biogeochemical cycles in the ocean will respond to global warming. We define the term "biogeochemical functional group" to refer to groups of organisms that mediate specific chemical reactions in the ocean. Thus, according to this definition, "functional groups" have no phylogenetic meaning-these are composed of many different species with common biogeochemical functions.

Substantial progress has …

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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 …

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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 …

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Open-Ocean Carbon Monoxide Photoproduction, Aron Stubbins, Günther Uher, Cliff S. Law, Kenneth Mopper, Carol Robinson, Robert C. Upstill-Goddard Jan 2006

Open-Ocean Carbon Monoxide Photoproduction, Aron Stubbins, Günther Uher, Cliff S. Law, Kenneth Mopper, Carol Robinson, Robert C. Upstill-Goddard

Chemistry & Biochemistry Faculty Publications

Sunlight-initiated photolysis of chromophoric dissolved organic matter (CDOM) is the dominant source of carbon monoxide (CO) in the open-ocean. A modelling study was conducted to constrain this source. Spectral solar irradiance was obtained from two models (GCSOLAR and SMARTS2). Water-column CDOM and total light absorption were modelled using spectra collected along a Meridional transect of the Atlantic ocean using a 200-cm pathlength liquid waveguide UV-visible spectrophotometer. Apparent quantum yields for the production of CO (AQYCO) from CDOM were obtained from a parameterisation describing the relationship between CDOM light absorption coefficient and AQYCO and the CDOM spectra collected. …

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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 …

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Winter 2006, Nsu Oceanographic Center Jan 2006

Winter 2006, Nsu Oceanographic Center

Currents

No abstract provided.

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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.

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The Hillarys Transect (1): Seasonal And Cross-Shelf Variability Of Physical And Chemical Water Properties Off Perth, Western Australia, 1996-98, Alan Pearce, Mervyn Lynch, Christine Hanson Jan 2006

The Hillarys Transect (1): Seasonal And Cross-Shelf Variability Of Physical And Chemical Water Properties Off Perth, Western Australia, 1996-98, Alan Pearce, Mervyn Lynch, Christine Hanson

Research outputs pre 2011

A 27-month study of the water properties across the continental shelf off Perth, Western Australia (the "Hillarys Transect") has provided the first systematic inter-disciplinary climatology of the physical, chemical, optical and biological cycles across the shelf. This paper describes the main features of the seasonal and cross-shelf variability of the physical oceanography and chemistry, while companion papers discuss some of the links between the biology and physics of the region

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