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Articles 2131 - 2160 of 2279

Full-Text Articles in Life Sciences

Near-Surface Phytoplankton Distribution In The Western Intra-Americas Sea: The Influence Of El Niño And Weather Events, Nelson M. Gonzalez, Frank E. Muller-Karger, Sergio Cerdeira Estrada, Roberto Perez De Los Reyes, Ivan Victora Del Rio, Pedro Cardenas Perez, Ida Mitrani Arenal Jun 2000

Near-Surface Phytoplankton Distribution In The Western Intra-Americas Sea: The Influence Of El Niño And Weather Events, Nelson M. Gonzalez, Frank E. Muller-Karger, Sergio Cerdeira Estrada, Roberto Perez De Los Reyes, Ivan Victora Del Rio, Pedro Cardenas Perez, Ida Mitrani Arenal

Marine Science Faculty Publications

The space-rime variation of phytoplankton pigments in the western Intra-Americas Sea (IAS), in the vicinity of the island of Cuba, is examined using digital images obtained with the Coastal Zone Color Scanner sensor flown aboard the Nimbus 7 satellite from 1978 to 1986. The results are compared to historical in situ hydrographic observations. A marked seasonality in pigment concentration was observed in waters around Cuba, with an average of 0.07 mg m(-3) in summer (April-September) and 0.13 mg m-3 during winter (October-March). The range of variation in pigment concentration was larger in the Gulf of Mexico relative to the western …

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The Effects Of Silviculture And Prescribed Burning On Herpetofauna In Florida Sand-Pine Scrub, Stig Ravdal Jun 2000

The Effects Of Silviculture And Prescribed Burning On Herpetofauna In Florida Sand-Pine Scrub, Stig Ravdal

USF Tampa Graduate Theses and Dissertations

Florida sand pine scrub is among the most endangered habitats in the United States and much of the remaining scrub is heavily influenced by management for timber production. In this study the effects of timber management practices on herpetofaunal community diversity and composition were investigated on experimentally manipulated plots near Orlando, Florida. Plots at three sites were either harvested, burned, or treated as a control (unmanipulated). Herpetofauna were trapped using pit-fall drift-fence trapping arrays. Animals were counted, measured, marked and released from March 1996 to June 1998. During this time period 1489 reptiles and amphibians were caught from 31 different …

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Form Ia Rbcl Transcripts Associated With A Low Salinity/High Chlorophyll Plume ('Green River') In The Eastern Gulf Of Mexico, John H. Paul, Albin Alfreider, Jordan B. Kang, Roger A. Stokes, Dale Griffin, Lisa Campbell, Erla Ornolfsdottir Jun 2000

Form Ia Rbcl Transcripts Associated With A Low Salinity/High Chlorophyll Plume ('Green River') In The Eastern Gulf Of Mexico, John H. Paul, Albin Alfreider, Jordan B. Kang, Roger A. Stokes, Dale Griffin, Lisa Campbell, Erla Ornolfsdottir

Marine Science Faculty Publications

Coastal plumes of low salinity water that extend hundreds of kilometers offshore into oligotrophic waters are often found in the Gulf of Mexico. To characterize one such feature, a series of photoautotrophic activity and biomass parameters were measured at 2 stations in the eastern Gulf of Mexico, including pigments by high performance liquid chromatography (HPLC), autotrophic picoplankton abundance by flow cytometry, photoautotrophic 14C-HCO3- fixation, and Ribulose-1,5-diphosphate carboxylase large subunit gene (rbcL) transcriptional activity. One sampling site (Stn 4) was in a 15 m deep, low salinity (29.8 ppt) plume 242 km west of Tampa Bay. …

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An Upwelling Case Study On Florida's West Coast, Robert H. Weisberg, Bryan D. Black, Zhenjiang Li May 2000

An Upwelling Case Study On Florida's West Coast, Robert H. Weisberg, Bryan D. Black, Zhenjiang Li

Marine Science Faculty Publications

Using a combination of satellite sea surface temperature imagery; in situ currents, temperature, and sea level data; and a numerical circulation model, we describe an upwelling event observed along Florida's west coast. Although ubiquitous features of continental shelves, descriptions of coastal upwellings (or downwellings) are generally complicated by the continuum of processes in which they occur. For the case study presented the winds were light, and the baroclinic background currents were steady for several days prior to the event. These conditions allow the evolution of a specific wind-driven upwelling event to be viewed as an initial value problem. The data …

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Vhf Radar Detects Oceanic Submesoscale Vortex Along Florida Coast, Lynn K. Shay, Thomas M. Cook, Brian Haus, Jorge Martinez, Hartmut Peters, Arthur J. Mariano, John Vanleer, P. E. An, Samuel Smith, A. Soloviev, Robert H. Weisberg, Mark E. Luther May 2000

Vhf Radar Detects Oceanic Submesoscale Vortex Along Florida Coast, Lynn K. Shay, Thomas M. Cook, Brian Haus, Jorge Martinez, Hartmut Peters, Arthur J. Mariano, John Vanleer, P. E. An, Samuel Smith, A. Soloviev, Robert H. Weisberg, Mark E. Luther

Marine Science Faculty Publications

Escalating national interest in the coastal ocean underscores the need for high‐quality surface current data that can improve our understanding of surface circulation and its impact on societal and environmental issues related to coastal pollution, beach restoration, oil spill mitigation, and coastal air‐sea interaction. Coastal regimes exposed to strong ocean currents,surface waves, and winds during storm conditions may frequently require beach renourishment to restore valuable beaches that are key to local economies. Maintaining water quality is a problem, too, particularly where shipping dominates the traffic in and out of harbors. These environmental issues are increasingly difficult to manage due to …

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Physical Factors Of Differentiation In Macrobenthic Communities Between Atoll Lagoons In The Central Tuamotu Archipelago (French Polynesia), Mehdi Adjeroud, Serge Andrefouet, Claude Payri, Joel Orempuller Apr 2000

Physical Factors Of Differentiation In Macrobenthic Communities Between Atoll Lagoons In The Central Tuamotu Archipelago (French Polynesia), Mehdi Adjeroud, Serge Andrefouet, Claude Payri, Joel Orempuller

Marine Science Faculty Publications

Nine atolls were characterized in order to understand how physical factors control the species composition, diversity, and abundance of macrobenthic (coral, mollusc, echinoderm, and algal) communities inside the lagoons. Only one region, the central part of Tuamotu Archipelago, French Polynesia, was considered, in order to minimise the variation due to regional factors between regions. The lagoons investigated showed a gradient of physical factors, providing various landscape configurations. The physical factors were surface area, abundance of pinnacles, degree of hydrodynamic aperture, and relative importance of passes in this degree of aperture. Macrobenthic communities were characterized by low diversity and strong dominance …

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Extrinsic Con The Evolution Of Hawaiian Ocean Island Volcanoes, David A. Clague, Jacqueline E. Dixon Apr 2000

Extrinsic Con The Evolution Of Hawaiian Ocean Island Volcanoes, David A. Clague, Jacqueline E. Dixon

Marine Science Faculty Publications

Extrinsic parameters that affect the evolution of magmatic systems within and beneath ocean island volcanoes include physical variables such as confining pressure, which controls magma degassing, and temperature of the underlying lithosphere and crust, which controls magma crystallization during ascent. Other extrinsic parameters are environmental variables coupled to the hydrosphere and atmosphere such as hydrothermal circulation systems and even rainfall. All these extrinsic factors interact with intrinsic parameters, such as magma supply rates or composition, to modulate the evolution of magma chambers and the petrologic processes that take place within them.

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Wind-Forced Reversing Jets In The Western Equatorial Pacific, Megan F. Cronin, Michael J. Mcphaden, Robert H. Weisberg Apr 2000

Wind-Forced Reversing Jets In The Western Equatorial Pacific, Megan F. Cronin, Michael J. Mcphaden, Robert H. Weisberg

Marine Science Faculty Publications

Upper-ocean zonal currents in the western equatorial Pacific are remarkably variable, changing direction both with time and depth. As a part of the Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment, an enhanced monitoring array of moorings measured the upper-ocean velocity, temperature, salinity, and, surface meteorological conditions in the western equatorial Pacific for two years (March 1992-April 1994). Data from this array are used to evaluate the zonal momentum balance. Although nonlinear terms (zonal. meridional, and vertical advection) were at times large, reversing jets were primarily due to an interplay between wind forcing and compensating pressure gradients. In the …

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Plankton Community Composition, Production, And Respiration In Relation To Dissolved Inorganic Carbon On The West Florida Shelf, April 1996, Gary L. Hitchcock, Gabriel A. Vargo, Mary-Lynn L. Dickson Mar 2000

Plankton Community Composition, Production, And Respiration In Relation To Dissolved Inorganic Carbon On The West Florida Shelf, April 1996, Gary L. Hitchcock, Gabriel A. Vargo, Mary-Lynn L. Dickson

Marine Science Faculty Publications

In April 1996 the Florida Shelf Lagrangian Experiment examined dissolved inorganic carbon (DIC) dynamics on the West Florida Shelf. DIC concentrations increased over 2 weeks at an average rate of 1 μmol kg−1 d−1 in a patch of the intentionally released tracers sulfur hexafluoride (SF6) and helium 3 (3He). Approximately 20% of the increase was due to air‐sea exchange with the remaining 80% attributed to plankton respiration [Wanninkhof et al., 1997]. Here we present particulate matter concentrations, phytoplankton production, and community respiration rates from the tracer patch that suggest that heterotrophs dominated …

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Characteristics Of Wind-Generated Rings In The Eastern Tropical Pacific Ocean, Frank E. Muller-Karger, Cesar Fuentes-Yaco Jan 2000

Characteristics Of Wind-Generated Rings In The Eastern Tropical Pacific Ocean, Frank E. Muller-Karger, Cesar Fuentes-Yaco

Marine Science Faculty Publications

Eddies are generated in the eastern tropical Pacific (3 degrees S-23 degrees N, 75 degrees-105 degrees W) by winds blowing through Central American mountain passes from the Atlantic. We used Coastal Zone Color Scanner (CZCS) and advanced very high resolution radiometer (AVHRR) satellite imagery complemented with monthly in situ sea surface temperature and wind series from the Comprehensive Ocean-Atmosphere Data Set (COADS) to study these eddies and their effect on pigment concentrations in the region. Pigment values in the Gulf of Tehuantepec generally reach higher values in November-March before those in the Gulf of Papagayo. The eddies generated in the …

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Interannual Mean Sea Level Change And The Earth's Water Mass Budget, Don P. Chambers, Jianli Chen, R. Steven Nerem, Byron D. Tapley Jan 2000

Interannual Mean Sea Level Change And The Earth's Water Mass Budget, Don P. Chambers, Jianli Chen, R. Steven Nerem, Byron D. Tapley

Marine Science Faculty Publications

The relationship between interannual global mean sea level change and the Earth's water mass budget is examined between 1993 and 1998 by removing the steric (thermal) component from mean sea level computed with TOPEX/Poseidon (T/P) altimetry. The steric component is calculated from subsurface temperatures measured by expendable bathythermographs and interpolated to a global grid by empirical orthogonal function (EOF) reconstruction. Results indicate that from late-1995 to early-1998, the thermal expansion of sea level was significantly higher than the total sea level change measured by T/P, suggesting that fresh water mass was lost from the ocean. The size of the maximum …

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Micro- And Macrodiversity In Rbcl Sequences In Ambient Phytoplankton Populations From The Southeastern Gulf Of Mexico, John H. Paul, Albin Alfreider, Boris Wawrik Jan 2000

Micro- And Macrodiversity In Rbcl Sequences In Ambient Phytoplankton Populations From The Southeastern Gulf Of Mexico, John H. Paul, Albin Alfreider, Boris Wawrik

Marine Science Faculty Publications

Ribulose-1,5-diphosphate carboxylase/oxygenase (RuBisCO) large subunit genes (rbcL) were obtained by amplification and cloning of 554 or 614 bp sequences of indigenous phytoplankton populations at 2 stations in the southeastern Gulf of Mexico. One station (Stn 4) was located in a low salinity, high chlorophyll plume (the ŒGreen River¹) which has previously been shown to contain elevated levels of Form IA rbcL mRNA while the other (Stn 7) was in oligotrophic, oceanic water. A diversity of rbcL sequences was obtained, spanning 3 of the 4 evolutionary clades of Form I RuBisCOs. Six nucleotide sequences obtained from Stn 4 were …

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Equatorial Upwelling In The Central Pacific Estimated From Moored Velocity Profilers, Robert H. Weisberg, Lin Qiao Jan 2000

Equatorial Upwelling In The Central Pacific Estimated From Moored Velocity Profilers, Robert H. Weisberg, Lin Qiao

Marine Science Faculty Publications

Horizontal divergence and vertical velocity (w) are estimated at 0°, 140°W using an array of five subsurface moored acoustic Doppler current profilers deployed from May 1990 to June 1991 during the Tropical Instability Wave Experiment. The record-length mean flow is divergent within the near-surface region and convergent within the thermocline, with maximum convergence located at the high speed core of the Equatorial Undercurrent (EUC). This pattern of divergence results in upwelling at and above the EUC core (with maximum value of 2.3 × 10−5 m s−1 located at 60-m depth) and downwelling below the core. The relative slopes in the …

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The Recommended Dissociation Constants For Carbonic Acid In Seawater, Kitack Lee, Frank J. Millero, Robert H. Byrne, Richard A. Feely, Rik Wanninkhof Jan 2000

The Recommended Dissociation Constants For Carbonic Acid In Seawater, Kitack Lee, Frank J. Millero, Robert H. Byrne, Richard A. Feely, Rik Wanninkhof

Marine Science Faculty Publications

A coherent representation of carbonate dissociation constants and measured inorganic carbon species is essential for a wide range of environmentally important issues such as oceanic uptake of anthropogenic CO2 and carbon cycle depictions in ocean circulation models. Previous studies have shown varying degrees of discordance between calculated and measured CO2-system parameters. It is unclear if this is due to errors in thermodynamic models or in measurements. In this work, we address this issue using a large field dataset (15,300 water samples) covering all ocean basins. Our field data, obtained using laboratory-calibrated measurement protocols, are most consistent with …

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Remote Sensing Observations Of Winter Phytoplankton Blooms Southwest Of The Luzon Strait In The South China Sea, Dan-Ling Tang, I-Hsun Ni, Dana R. Kester, Frank E. Muller-Karger Dec 1999

Remote Sensing Observations Of Winter Phytoplankton Blooms Southwest Of The Luzon Strait In The South China Sea, Dan-Ling Tang, I-Hsun Ni, Dana R. Kester, Frank E. Muller-Karger

Marine Science Faculty Publications

The Luzon Strait is a channel between the Philippine Sea and the South China Sea. This area is traditionally classified as an oligotrophic zone with low primary productivity. Even so, high concentrations of pigment were detected 100 km southwest of the Strait through analysis of historical Coastal Zone Color Scanner (CZCS) data that the Nimbus-7 satellite collected during the winters of 1979 to 1986. These blooms were observed in December 1979, February 1983, February 1985, and January 1986, when sea surface temperatures measured with the National Oceanic and Atmospheric Administration's (NOAAs) Advanced Very High Resolution Radiometer (AVHRR) were 23 to …

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West Florida Continental Shelf Response To Upwelling Favorable Wind Forcing 2. Dynamics, Zhenjiang Li, Robert H. Weisberg Oct 1999

West Florida Continental Shelf Response To Upwelling Favorable Wind Forcing 2. Dynamics, Zhenjiang Li, Robert H. Weisberg

Marine Science Faculty Publications

Dynamics analyses are presented for the west Florida continental shelf response to upwelling favorable, alongshore or offshore winds using a three-dimensional, time-dependent, primitive equation model. These analyses complement the kinematics analyses of Li and Weisberg [1999]. Results are provided on four topics: (1) the response evolutions to quasi steady states, (2) the across-shelf distributions of the vertically integrated alongshore and across-shelf momentum balances, (3) the three-dimensional structures of the terms composing the momentum balance closures, and (4) the model sensitivity to vertical friction parameterization. The response evolution starts with a local wind-driven acceleration, and it transitions over the inner shelf …

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Tropical Pacific Near-Surface Currents Estimated From Altimeter, Wind, And Drifter Data, Gary S. E. Lagerloef, Gary T. Mitchum, Roger B. Lukas, Pearn P. Niiler Oct 1999

Tropical Pacific Near-Surface Currents Estimated From Altimeter, Wind, And Drifter Data, Gary S. E. Lagerloef, Gary T. Mitchum, Roger B. Lukas, Pearn P. Niiler

Marine Science Faculty Publications

Tropical surface currents are estimated from satellite-derived surface topography and wind stress using a physically based statistical model calibrated by 15 m drogue drifters. The model, assumes a surface layer dominated by steady geostrophic and Ekman dynamics. Geostrophy varies smoothly from a beta plane formulation at the equator to an f plane formulation in midlatitude, with the transition occurring at similar to 2 degrees-3 degrees latitude. The transition is treated with a Gaussian weight function having a meridional decay scale that is found to be approximately the Rossby radius (similar to 2.2 degrees latitude). The two-parameter Ekman model represents drifter …

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Validation Of Coral Temperature Calibrations, Thomas J. Crowley, Terrence M. Quinn, William T. Hyde Oct 1999

Validation Of Coral Temperature Calibrations, Thomas J. Crowley, Terrence M. Quinn, William T. Hyde

Marine Science Faculty Publications

Geochemical analyses of coral skeletons are increasingly used to estimate past sea surface temperatures (SSTs). In this paper we suggest that the standard method of calibrating geochemical time series against a (usually short) local time series requires modification. In order to draw large‐scale inferences about climate from coral proxy data it is also necessary to (1) calibrate against larger fields such as the local gridded data sets and (2) validate results against an independent data set (e.g., early 20th century). This approach has been applied in a pilot study to a coral record from New Caledonia. Despite a high δ18O …

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West Florida Shelf Response To Upwelling Favorable Wind Forcing: Kinematics, Zhenjiang Li, Robert H. Weisberg Jun 1999

West Florida Shelf Response To Upwelling Favorable Wind Forcing: Kinematics, Zhenjiang Li, Robert H. Weisberg

Marine Science Faculty Publications

The barotropic responses of the west Florida continental shelf to idealized upwelling favorable alongshore and offshore wind stresses are studied using the three-dimensional, time-dependent, primitive equation Princeton Ocean Model (POM). When forced with uniform winds, the shelf circulation evolves quickly to a quasi steady state. A southeastward alongshore wind lowers sea level along the coast and drives a southeastward coastal jet with a relatively weak northwestward return flow farther offshore. A southwestward offshore wind lowers sea level along the west Florida coast and raises sea level along the Panhandle coast. Two independent circulation gyres are set up in association with …

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Simulation Of Carbon-Nitrogen Cycling During Spring Upwelling In The Cariaco Basin, John J. Walsh, Dwight A. Dieterle, Frank E. Muller-Karger, Richard Bohrer, W. Paul Bissett, Ramon J. Varela, Ruben Aparicio, Rafael Diaz, Robert Thunell, Gordon T. Taylor, Mary I. Scranton, Kent A. Fanning, Edward T. Peltzer Apr 1999

Simulation Of Carbon-Nitrogen Cycling During Spring Upwelling In The Cariaco Basin, John J. Walsh, Dwight A. Dieterle, Frank E. Muller-Karger, Richard Bohrer, W. Paul Bissett, Ramon J. Varela, Ruben Aparicio, Rafael Diaz, Robert Thunell, Gordon T. Taylor, Mary I. Scranton, Kent A. Fanning, Edward T. Peltzer

Marine Science Faculty Publications

Coupled biological-physical models of carbon-nitrogen cycling by phytoplankton, zooplankton, and bacteria assess the impacts of nitrogen fixation and upwelled nitrate during new production within the shelf environs of the Cariaco Basin. During spring upwelling in response to a mean wind forcing of 8 m s(-1), the physical model matches remote-sensing and hydrographic estimates of surface temperature. Within the three-dimensional flow field, the steady solutions of the biological model of a simple food web of diatoms, adult calanoid copepods, and ammonifying/nitrifying bacteria approximate within similar to 9% the mean spring observations of settling fluxes caught by a sediment trap at similar …

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Particle Trajectories In An Indian Ocean Model And Sensitivity To Seasonal Forcing, Meredith A. Haines, Rana A. Fine, Mark E. Luther, Zaihua Ji Apr 1999

Particle Trajectories In An Indian Ocean Model And Sensitivity To Seasonal Forcing, Meredith A. Haines, Rana A. Fine, Mark E. Luther, Zaihua Ji

Marine Science Faculty Publications

Trajectory experiments in a thermocline layer of an Indian Ocean model are used to investigate the role of different meridional transport mechanisms and quantify spreading pathways and rates under different forcing. Particles are introduced along two boundaries: the south Indian Ocean at 30 degrees S and the Indonesian Throughflow. Particles are advected horizontally within the layer by archived model velocity fields (1/3 degrees X 1/3 degrees resolution) for a period of 50 years. The velocity fields are the result of forcing the model by monthly mean climatology (case A). The distribution of particles within the Tropics suggests efficient ater mass …

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Semianalytic Moderate-Resolution Imaging Spectrometer Algorithms For Chlorophyll A And Absorption With Bio-Optical Domains Based On Nitrate-Depletion Temperatures, Kendall L. Carder, F. R. Chen, Z. P. Lee, S. K. Hawes, D. Kamykowski Mar 1999

Semianalytic Moderate-Resolution Imaging Spectrometer Algorithms For Chlorophyll A And Absorption With Bio-Optical Domains Based On Nitrate-Depletion Temperatures, Kendall L. Carder, F. R. Chen, Z. P. Lee, S. K. Hawes, D. Kamykowski

Marine Science Faculty Publications

This paper describes algorithms for retrieval of chlorophyll a concentration and phytoplankton and gelbstoff absorption coefficients for the Moderate-Resolution Imaging Spectrometer (MODIS) or sensors with similar spectral channels. The algorithms are based on a semianalytical, bio-optical model of remote sensing reflectance, Rrs([lambda]). The Rrs([lambda]) model has two free variables, the absorption coefficient due to phytoplankton at 675 nn, a[Phi](675), and the absorption coefficient due to gelbstoff at 400 nm, ag(400). The Rrs model has several parameters that are fixed or can be specified based on the region and season of the …

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Western Pacific Interannual Variability Associated With The El Niño‐Southern Oscillation, Chunzai Wang, Robert H. Weisberg, Jyotika I. Virmani Mar 1999

Western Pacific Interannual Variability Associated With The El Niño‐Southern Oscillation, Chunzai Wang, Robert H. Weisberg, Jyotika I. Virmani

Marine Science Faculty Publications

Observations of sea surface temperature (SST), sea level pressure (SLP), surface wind, and outgoing longwave radiation (OLR) show that the El Niño‐Southern Oscillation (ENSO) displays western Pacific anomaly patterns in addition to eastern Pacific anomaly patterns. During the warm phase of ENSO, warm SST and low SLP anomalies in the equatorial eastern Pacific and low OLR anomalies in the equatorial central Pacific are accompanied by cold SST and high SLP anomalies in the off‐equatorial western Pacific and high OLR anomalies in the off‐equatorial far western Pacific. Also, while the zonal wind anomalies over the equatorial central Pacific are westerly, those …

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Response Of The West Florida Shelf Circulation To Climatological Wind Stress Forcing, Huijun Yang, Robert H. Weisberg Mar 1999

Response Of The West Florida Shelf Circulation To Climatological Wind Stress Forcing, Huijun Yang, Robert H. Weisberg

Marine Science Faculty Publications

The response of the west Florida: continental shelf circulation to monthly mean climatological wind forcing is investigated by using the three-dimensional, primitive equation Princeton Ocean Model. Two basic seasonal patterns of circulation and sea surface elevation occur under a barotropic setting: A winter pattern from October to March and a summer pattern from April to September. An interesting finding in winter is an anticyclonic gyre over the northeastern (Florida Big Bend) region that merges with a northwestward flow from the south. The Big Bend Gyre is caused by a convergence of two separate flows: A nearshore along-shelf southeastward flow and …

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Non‐Redfield Carbon And Nitrogen Cycling In The Arctic: Effects Of Ecosystem Structure And Dynamics, Kendra L. Daly, Douglas W. R. Wallace, Walker O. Smith Jr., Annelie Skoog, Rubén Lara, Michel Gosselin, Eva Falck, Patrick L. Yager Feb 1999

Non‐Redfield Carbon And Nitrogen Cycling In The Arctic: Effects Of Ecosystem Structure And Dynamics, Kendra L. Daly, Douglas W. R. Wallace, Walker O. Smith Jr., Annelie Skoog, Rubén Lara, Michel Gosselin, Eva Falck, Patrick L. Yager

Marine Science Faculty Publications

The C:N ratio is a critical parameter used in both global ocean carbon models and field studies to understand carbon and nutrient cycling as well as to estimate exported carbon from the euphotic zone. The so‐called Redfield ratio (C:N = 6.6 by atoms) [Redfield et al., 1963] is widely used for such calculations. Here we present data from the NE Greenland continental shelf that show that most of the C:N ratios for particulate (autotrophic and heterotrophic) and dissolved pools and rates of transformation among them exceed Redfield proportions from June to August, owing to species composition, size, and …

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Orbitally-Tuned Sr Isotope Chemostratigraphy For The Late Middle To Late Miocene, E. E. Martin, N. J. Shackleton, J. C. Zachos, Benjamin P. Flower Feb 1999

Orbitally-Tuned Sr Isotope Chemostratigraphy For The Late Middle To Late Miocene, E. E. Martin, N. J. Shackleton, J. C. Zachos, Benjamin P. Flower

Marine Science Faculty Publications

We present a Sr chemostratigraphic reference section for the late middle to late Miocene (14-5 Ma) from Ocean Drilling Program site 926 on the Ceara Rise. This site combines a precise, orbitally tuned timescale with a high sedimentation rate (15 m/m.y.), continuous deposition, and excellent biostratigraphic control. The Sr isotope curve is based on measurements of cleaned, planktonic foraminifera at 100-200 kyr sample intervals and it illustrates periods of rapid change in Sr-87/Sr-86 alternating with periods of little change. Chemostratigraphically-defined ages for these intervals can be determined within +/-0.8 m.y. and +/-1.6 m.y, respectively. There is excellent correlation with the …

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Anomalous Warming In The Indian Ocean Coincident With El Niño, D. P. Chambers, B. D. Tapley, R. H. Stewart Jan 1999

Anomalous Warming In The Indian Ocean Coincident With El Niño, D. P. Chambers, B. D. Tapley, R. H. Stewart

Marine Science Faculty Publications

The TOPEX/POSEIDON altimeter has provided further evidence that interannual warming occurs in the Indian Ocean with a frequency similar to that of El Niño in the Pacific and has yielded important clues to the dynamics driving the warming. The signal is especially strong during the 1997 El Niño. The altimeter observes long waves which move westward from the southeastern Indian Ocean at about the same time as westwardly wind anomalies appear in the east-central portion of the basin. The sea level peaks in the southwestern Indian Ocean and causes a sea level variation signal that is a near mirror image …

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Variations In Global Mean Sea Level Associated With The 1997–1998 Enso Event: Implications For Measuring Long Term Sea Level Change, R. S. Nerem, D. P. Chambers, E. W. Leuliette, Gary T. Mitchum, B. S. Giese Jan 1999

Variations In Global Mean Sea Level Associated With The 1997–1998 Enso Event: Implications For Measuring Long Term Sea Level Change, R. S. Nerem, D. P. Chambers, E. W. Leuliette, Gary T. Mitchum, B. S. Giese

Marine Science Faculty Publications

The TOPEX/POSEIDON satellite has observed variations in global mean sea level with a precision of 4 mm at 10-day intervals since late 1992. During the 1997–1998 ENSO event, a 20 mm rise, and subsequent fall, of mean sea level was observed. These changes are well correlated with global mean sea surface temperature anomalies, which exhibit a similar response for every major ENSO event since 1981, suggesting the observed mean sea level change is mostly caused by thermal expansion. An Empirical Orthogonal Function analysis of the altimeter-derived sea level maps also suggests a connection with ENSO. We observed the same signal …

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Genetic Variation In Chrysopsis Floridana Small, The Endangered Florida Golden Aster, As Revealed By Random Amplification For Polymorphism Detection (Rapd), Laurie Lysle Walker Markham Nov 1998

Genetic Variation In Chrysopsis Floridana Small, The Endangered Florida Golden Aster, As Revealed By Random Amplification For Polymorphism Detection (Rapd), Laurie Lysle Walker Markham

USF Tampa Graduate Theses and Dissertations

Chrysopsis fioridana Small (Asteraceae) is a federally endangered plant endemic to the Tampa Bay area of west central Florida. It is confined to the sand pine scrub community, growing in open, sunny, and sandy areas or in disturbed areas at the edges of scrub. As a means ofassessing the genetic variability ofthis species, eight populations in Hillsborough County were compared with a seed stock collection housed at Bok Tower Gardens in Lake Wales using random amplification for polymorphism detection (RAPD). The objectives of this study were to (I) describe the overall genetic variation among and within populations and subpopulations of …

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An Empirical Algorithm For Light Absorption By Ocean Water Based On Color, Zhongping Lee, Kendall L. Carder, R. G. Steward, T. G. Peacock, C. O. Davis, J. S. Patch Nov 1998

An Empirical Algorithm For Light Absorption By Ocean Water Based On Color, Zhongping Lee, Kendall L. Carder, R. G. Steward, T. G. Peacock, C. O. Davis, J. S. Patch

Marine Science Faculty Publications

Empirical algorithms for the total absorption coefficient and absorption coefficient by pigments for surface waters at 440 nm were developed by applying a quadratic formula that combines two spectral ratios of remote-sensing reflectance. For total absorption coefficients ranging from 0.02 to 2.0 m(-1), a goodness of fit was achieved between the measured and modeled data with a root-mean-square difference between the measured and modeled values for log10 scale (RMSDlog10) of 0.062 (15.3% for linear scale, number of samples N = 63), while RMSDlog10 is 0.111 (29.1% for linear scale, N = 126) for pigment absorption (ranging from 0.01 to 1.0 …

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