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Vertical Structure Of Low-Frequency Variability In The Eastern Equatorial Pacific Ocean, T. Y. Tang, Robert H. Weisberg, D. Halpern

Marine Science Faculty Publications

The vertical structure of low frequency velocity and temperature variability in the eastern equatorial Pacific Ocean is examined using surface and subsurface moored current meter data from 0°, 110°W between 20 and 3027 m depths over the period 30 March 1980 to 2 February 1981. Three methods of analysis are employed: vertical coherence, empirical orthogonal functions, and linear least-squares dynamical mode decompositions. Direct evidence is given for the existence of first baroclinic mode Kelvin waves in the east component of velocity and vertical displacement (estimated from temperature) in that the vertical displacement is coherent and in phase over the water …

Verification Of A Numerical Ocean Model Of The Arabian Sea, Ray C. Simmons, Mark E. Luther, James J. O'Brien, David M. Legler

Marine Science Faculty Publications

A case study evaluating the predictive capability of an upper layer circulation model of the northwest Indian Ocean is presented. The model is a nonlinear, reduced gravity model incorporating realistic boundary geometry and is forced by observed winds. Model results for the fall of 1985 are compared with and evaluated against U.S. Navy bathythermograph and NOAA satellite data collected during August–November 1985. An assessment is made of the model's ability to simulate correctly the circulation structure. Ship wind observations are converted to wind stress for model forcing by a procedure developed by Legler and Navon (1988). The model is only …

The Mathematician Paleoplate, J. Mammerickx, D. F. Naar, R. L. Tyce

Marine Science Faculty Publications

The Pacific seafloor is littered with small fragments of lithosphere captured from adjacent plates by past plate boundary reorganizations. One of the clearest examples of such a reorganization is documented in the Mathematician Seamounts region, where a distinctive geomorphology and well-developed magnetic anomalies are present. This reorganization involved a short-lived microplate between the failing Mathematician Ridge and a new propagating spreading center: the East Pacific Rise. It produced a transfer of a fragment of lithosphere from the Farallon to the Pacific plate, and also created a number of landforms and magnetic patterns, within and on the margins of the captured …

Abundance And Distribution Of Herbaceous Angiosperms In Grass-Sedge Marshes Of West-Central Florida: The Effect Of Seasonal Water-Level Fluctuation, Pamela S. Botts

USF Tampa Graduate Theses and Dissertations

Grass-sedge marshes in west-central Florida were studied to determine the abundances and distributions of herbaceous angiosperms. Cluster analysis, reciprocal averaging, and a biotic boundaries technique were used to analyze the relationship between community composition and depth within the marsh. Shallow areas were dominated by Rhynchospora filifolia, Dichanthelium sabulorum, and Rhynchospora cephalantha. Abundances of the species fluctuated seasonally and varied between marshes. Deep areas of individual marshes differed markedly from shallow areas and from each other. A deep, well-drained marsh supported a monospecific stand of Juncus repens, while a less deep, but poorly drained marsh had a …

Distribution And Molecular Weight Of Dissolved Dna In Subtropical Estuarine And Oceanic Environments, Mary F. Deflaun, John H. Paul, Wade H. Jeffrey

Marine Science Faculty Publications

Dissolved DNA and a series of microbial biomass and activity parameters were measured in offshore, coastal, estuarine and coral reef environments of the southeast Gulf of Mexico. Oceanic concentrations of dissolved DNA ranged from 0.2 to 19 μg 1^-1 and decreased as a function of distance from shore and depth in the water column. Dissolved DNA concentrations were greater than half the particulate DNA content in offshore environments (̄x̄ = 63 ± 45 %) but were a smaller percentage of particulate DNA in nearshore and estuarine environments (̄x̄ = 35 ± 21 %). Dissolved DNA correlated better with bacterial …

Velocity And Temperature Observations During The Seasonal Response Of The Equatorial Atlantic Experiment At 0 Degrees, 28 Degrees W, Robert H. Weisberg, J. H. Hickman, T. Y. Tang, T. J. Weingartner

Marine Science Faculty Publications

Continuous 2.7‐year time series of upper ocean currents and temperature at 0°, 28°W collected during the Seasonal Response of the Equatorial Atlantic Experiment are presented. The thermocline underwent distinctive annual cycles in response to forcing by the surface wind stress, and the core of the Equatorial Undercurrent tracked the thermocline. While the vertical position of the thermocline and the undercurrent appear to be simply related, the transport of the undercurrent did not show a replicating annual cycle, and the speed at the undercurrent core remained relatively constant. Near surface flow when averaged over the 2.7 years was not statistically different …

M2 Tidal Currents In The Eastern Equatorial Pacific Ocean, Robert H. Weisberg, D. Halpern, T. Y. Tang, S. M. Hwang

Marine Science Faculty Publications

Current meter measurements recorded over the water column at 10 depths ranging from 20 m to 3027 m using surface and subsurface moorings near 0°, 110°W are analyzed for the M₂ tidal current over a 10‐month sampling interval. A kinematical description is given by month and depth, followed by a decomposition into a barotropic mode and three baroclinic modes. The barotropic tide was dominant, and its hodograph was stable over the 10 months sampled. The baroclinic tide was random, isotropic, and without mode preference.

Further Studies On The Response Of The Equatorial Thermocline In The Atlantic Ocean To The Seasonally Varying Trade Winds, Robert H. Weisberg, T. Y. Tang

Marine Science Faculty Publications

Upper ocean temperature data obtained during the Seasonal Response of the Equatorial Atlantic experiment and the Francais Ocean et Climat dans l'Atlantique Equatorial program are used to describe the variations of the thermocline observed along the equator from February 1983 to September 1984. In response to rapid seasonal changes in zonal wind stress, the thermocline underwent sequences of upwelling followed by downwelling or conversely, depending upon whether the winds were intensifying or relaxing. These sequences increased systematically in magnitude and duration to the east. Both the sequential behavior and its zonal inhomogeneity represent departures from the slowly varying and in-phase …

What Controls Tropical Reef Fish Populations: Recruitment Or Benthic Mortality? An Example In The Caribbean Reef Fish Haemulon Flavolineatum, M. J. Shulman, John C. Ogden

Integrative Biology Faculty and Staff Publications

Recruitment from a planktonic larval stage has been proposed to be an important factor in limiting populations of marine organisms, particularly tropical reef fishes. We monitored recruitment and population densities of juvenile size classes In French grunt Haemulon flavolineatum (Haemulidae) from October 1978 through December 1980 In a portion of Tague Bay, St. Croix, U. S. Virgin Islands. Within our study area, 95 % of new recruits settled onto the sand and seagrass lagoon floor and within a few weeks migrated to nearby reefs; the remaining 5'10 settled directly onto reef structures. Mean annual recruitment rate was 1.8 recruits per …

Trade Wind Fluctuations Associated With El Niño-Southern Oscillation Events, Gary T. Mitchum

Marine Science Faculty Publications

Wind fields associated with El Niño-Southern Oscillation (ENSO) events are investigated using 20 years (1965–1984) of monthly mean wind vectors along a ship track from 30°S to 30°N in the western Pacific Ocean. The analysis shows that off-equatorial trade wind fluctuations play a significant role in ENSO events. In particular, the meridional component is found to have strong deviations during ENSO events. Southerly deviations from the mean meridional field are noted during the ENSO events of 1965, 1972, 1976, and 1982. The trade wind deviations are consistent with atmospheric convergence into an equatorial convection region to the east of the …

A Bias In The Satellite-Observed Low-Level Cloud Motion Winds Over The Central Tropical Pacific, Gary T. Mitchum

Marine Science Faculty Publications

Island wind data from the central tropical Pacific are compared with satellite-observed low-level cloud motion winds over the same area during 1976–1980. The purpose of the comparison is to investigate the effect of gaps in the satellite wind series. It is found that the distribution of the gaps is such that the resulting time series is biased from the complete time series because of undersampling of the strongest westerly and northerly wind anomalies. This bias is strong enough, at least in this geographical region, to cause difficulties in estimating accurate mean fields from the cloud motion winds alone. The gaps …

Elevated Levels Of Microbial Activity In The Coral Surface Microlayer, John H. Paul, Mary F. Deflaun, Wade H. Jeffrey

Marine Science Faculty Publications

No abstract provided.

The Diet Of The Gopher Tortoise, Gopherus Polyphemus, In A Sandhill Habitat In Central Florida, Laurie Ann Macdonald

USF Tampa Graduate Theses and Dissertations

Scat analysis and foraging observations were used to determine the diet of a gopher tortoise, Gopherus polyphemus, population in a sandhill community in west central Florida. Live vegetation was assessed to determine plant availability. The bulk of the gopher tortoise diet was composed of the dominant plant species in the habitat while the tortoises were selective with respect to most plant genera. Tortoises ingested many plant taxa with Poaceae, Asteraceae, Fabaceae, Pinaceae and Fagaceae being the most frequent components of the diet. Sixty-eight genera from 26 families were identified in the tortoise diet. In the scat the most common …

Gabbroic Xenoliths And Host Ferrobasalt From The Southern Juan De Fuca Ridge, Jacqueline Eaby Dixon, David A. Clague, Jean‐Philippe Eissen

Marine Science Faculty Publications

Rare isotropic gabbroic xenoliths occur in sheet and lobate flow fragments of nearly aphyric ferrobasalt collected along a 12‐km section of the southern Juan de Fuca Ridge. Xenoliths comprise ≪ 1% of the dredge contents and range in size from 1 cm³ (glomerocryst) to 240 cm³. The xenoliths have ophitic to intersertal texture with 5–50% interstitial glass of ferrobasaltic composition more evolved than the host lava. On the basis of texture and mineralogy, the xenoliths have been subdivided into three types: type I, plagioclase + olivine + glass; type II, plagioclase + augite + glass ± olivine; …

Fast Rift Propagation Along The East Pacific Rise Near Easter Island, David F. Naar, R. N. Hey

Marine Science Faculty Publications

During a 1983 Seabeam cruise, we surveyed the Easter-Nazca spreading center which forms the eastern boundary of the Easter microplate. We have analyzed all available bathymetry and magnetic anomaly data to determine the present fine-scale tectonic configuration and recent tectonic evolution of this spreading center. The narrowing of the axial (Brunhes) anomaly is best explained by a young propagating rift growing northward at an average rate of 150 mm/yr assuming an average spreading rate of 120 mm/yr. There are indications of a short episode of faster propagation (350 mm/yr) prior to 0.4 Ma. These are the fastest rates of rift …

Stable Hydrogen And Carbon Isotopic Compositions Of Biogenic Methanes, Roger Allen Burke Jr.

USF Tampa Graduate Theses and Dissertations

Stable hydrogen and carbon isotopic compositions of biogenic methanes collected from the sediments of several deep-sea, nearshore marine-estuarine, and freshwater environments were determined. The isotopic compositions of methane samples from eight different DSDP Sites (mean σD-CH₄ = -185⁰>/∞, std. dev. = 7⁰>/∞, n = 75; mean σ¹³C-CH₄ = -71.3⁰/∞, std. dev. = 6.3⁰/∞, n = 44) are generally typical of methane formed via C0₂ reduction in deep-sea sediments.

Methane collected from several freshwater environments was D-depleted (mean σD-CH₄ = -300⁰>/∞ , std. dev. = …

Uptake Of Zn65 And Mn54 Into Body Tissues And Renal Granules By The Southern Quahog, Mercenaria Campechiensis, William Lynn Miller Jr.

USF Tampa Graduate Theses and Dissertations

A study was conducted to examine the influence of elevated inorganic phosphate and trace metal concentrations on the uptake and distribution of Zn⁶⁵ and Mn⁵⁴ into the body tissue and phosphoritic renal concretions of a subtropical estuarine bivalve, Mercenaria campechiensis. Chronological sampling of gills, mantle, adductor muscle, viscera, kidneys, and renal granules using gamma ray spectrometry allowed examination of both tissue distribution and accumulation patterns over time. The kidney was the principal site of Mn⁵⁴ accumulation whereas Zn⁶⁵ was concentrated in both the gill and the kidney. The gill initially accumulated zn65 three times faster …

On The Response Of The Equatorial Thermocline In The Atlantic Ocean To The Seasonally Varying Trade Winds, Robert H. Weisberg, T. Y. Tang

Marine Science Faculty Publications

Measurements made during the Seasonal Response of the Equatorial Atlantic experiment in 1983, when the easterly trade winds near the equator ceased and then intensified as part of their annual cycle, show a sequence of events leading to an adjusted thermocline. Both the duration and extent of the downwelling and upwelling associated with the adjustment process were zonally inhomogeneous along the equator. An analytical reduced gravity model was driven by a hierarchy of easterly wind stress forcing functions representative of the Atlantic to compare the integral nature of the forced long-wave responses with the observations. Qualitative agreement was found with …

Equatorial Atlantic Velocity And Temperature Observations: February-November 1981, Robert H. Weisberg

Marine Science Faculty Publications

Upper ocean velocity and temperature measurements were obtained in the central equatorial Atlantic using surface moored current meters from February to November 1981. Distinct seasonal variations were observed in the zonal momentum and temperature on the equator of both the surface South Equatorial Current (SEC) and the subsurface Equatorial Undercurrent (EUC). After initially intensifying during boreal spring the SEC halted abruptly in early summer and the signature associated with this change progressed. At the observational depth of 100 m both speed and temperature increased during early summer with eastward progression and then decreased in fall. Higher frequency motions were also …

Mixed Instabilities In The Gulf Stream Over The Continental Slope, Mark E. Luther, John M. Bane

Marine Science Faculty Publications

A numerical model study is presented of the unstable normal modes of oscillation of a boundary current. The model background current approximates the Gulf Stream south of Cape Hatteras, North Carolina. Both vertical and horizontal shear in current velocity and a sloping bottom topography are included. The study seeks small amplitude, alongshore propagating perturbations with real frequency and complex alongshore wavenumber. A nonzero imaginary part of the wavenumber ensures that the wave amplitude either grows or decays in the alongshore direction. The first four eigenmodes are identified and their dispersion relations are investigated. Higher order modes are not resolved by …

Verification Of A Numerical Ocean Model Of The Arabian Sea, Ray C. Simmons, Mark E. Luther

Marine Science Faculty Publications

A case study evaluating the predictive capability of an upper layer circulation model of the northwest Indian Ocean is presented. The model is a nonlinear, reduced gravity model incorporating realistic boundary geometry and is forced by observed winds. Model results for the fall of 1985 are compared with and evaluated against U.S. Navy bathythermograph and NOAA satellite data collected during August–November 1985. An assessment is made of the model's ability to simulate correctly the circulation structure. Ship wind observations are converted to wind stress for model forcing by a procedure developed by Legler and Navon (1988). The model is only …

Recruitment Patterns In Young French Grunts, Haemulon Flavolineatum (Family Haemulidae), At St. Croix, Virgin Islands., William N. Mcfarland, E. B. Brothers, John C. Ogden, Myra J. Shulman, E. L. Bermingham, N. M. Kotachian-Prentiss

Integrative Biology Faculty and Staff Publications

No abstract provided.

Factors Influencing The Degree Of Saturation Of The Surface And Intermediate Waters Of The North Pacific Ocean With Respect To Aragonite, Richard A. Feely, Robert H. Byrne, Peter R. Betzer, James F. Gendron, James G. Acker

Marine Science Faculty Publications

New carbonate chemistry data obtained during a 1982 cruise have been combined with earlier GE‐OSECS and INDOPAC data to determine the degree of aragonite saturation of surface and intermediate waters of the North Pacific. Large gradients in saturation state occur in the region of the Subarctic Front in the north‐south direction and across the Subtropical Gyre in the east‐west direction. These gradients are primarily due to the extensive mixing that occurs in the intermediate waters of the western North Pacific. The major variations in saturation state were primarily related to the carbonate ion concentration, which, in turn, is primarily a …

Sr Isotopic Variations Along The Juan De Fuca Ridge, Jacqueline Eaby, David A. Clague, John R. Delaney

Marine Science Faculty Publications

Sr isotopic ratios of 39 glass and microcrystalline basalt samples along the Juan de Fuca Ridge and 1 glass sample from Brown Bear Seamount are at the lower end of the range for normal mid‐oceanic ridge basalt (MORB); the average ⁸⁷Sr/⁸⁶Sr ratio is 0.70249±0.00014 (2‐σ). Although subtle variations exist along strike of the ridge, the Sr isotope data do not show systematic variation relative to the proposed Cobb Hotspot. The isotopic data are inconsistent with an enriched mantle‐plume origin for the Cobb‐Eickelberg Seamount chain, as has been proposed for Iceland, the Azores, and the Galapagos spreading center. …

Herbivory Effects On Thalassia Testudinum Leaf Growth And Nitrogen Content, J. C. Zieman, R. L. Iverson, John C. Ogden

Integrative Biology Faculty and Staff Publications

The pattern of turtle grazing on Thalassia testudinum in St. Croix seagrass beds begins with the establishment of a grazing plot by initial removal of leaf blades, followed by repeated grazing of several centimeter-long leaf blades within a maintained grazing area. Plants within the grazed area exhibit increased specific growth rate as a consequence of increased light flux to unepiphytized leaf bases. Leaf width is reduced in the grazed area as a consequence of grazing stress. The leaf bases contain a higher proportion of nitrogen and a lower lignin content than the leaf tips, in addition to lacking epiphytes. Our …

Behavior, Habitat Use, Food, And Foraging Efficiency Of Three Species Of Sympatric Merons (Egretta), Donald M. Kent

USF Tampa Graduate Theses and Dissertations

The foraging ecology and behavior of Little Bule Herons (Egretta caerulea), Snowy Egrets (E. thula), and Tricolored Herons (E. tricolor) was studied from October 1981 to August 1982 in Old Tampa Bay and Safety Harbor, Hills borough and Pinellas Counties, Florida. Little Blue Herons foraged exclusively by walk-slow and employed head sways or tilted during 75% of the observations. Snowy Egrets used stand, walk-slow, disturb-and-chase, and foot-stirring. Tricolored Herons used stand, walk-slow, disturb-and-chase, ana stand-and-chase. Tricolored Herons using stand-and-chase stood near shore facing open water and when prey was spotted they ran or hopped in the direction of the prey …

Demography, Movements, Activity, Habitat Utilization And Marking Behavior Of A Bobcat (Lynx Rufus) Population In South-Central Florida, Douglas A. Wassmer

USF Tampa Graduate Theses and Dissertations

Eighteen (6 male and 7 female adults, 5 juveniles) radio-collared bobcats (Lynx rufus) were monitored on the Archbold Biofogical Station and vicinity during 1979-1982. Mean density was 0.06 males, 0.11 females, and 0.19 juveniles per 100 ha. Mean sex and age ratios were 0.6 adult males per adult female and 1.22 juveniles per adult. Breeding occurred from September to March. Mean size of 13 mobile litters was 2.5 (range 1-4). Nine (50%) of 18 collared cats died. Nine additional individuals were found dead or reported killed. Known causes of 16 deaths were: road-killed 8, feline panleukopenia or notoedric …

Trophodynamics Of The Fish Valenciennellus Tripunctulatus. I. Vertical Distribution, Diet And Feeding Chronology, Thomas L. Hopkins, Ronald C. Baird

Marine Science Faculty Publications

The adult and juvenile life stages of the small (~25mm) zooplanktivorous mesopelagic fish Valenciennellus tripunctulatus (Esmark) are found at depths of 200-600m throughout the diel period. Average population density was estimated to be 5 fish (104m³)^-1 and the maximum density recorded was 11 fish (104m³)^-1. Copepods constituted ~95% of all food items identified and Pleuromamma was the principal forage genus, contributing 31% and 56% to numbers and biomass of food items, respectively. Ontogenetic changes in diet were observed, the percentage of larger copepods increasing in the diet with increasing fish size. Food items …

Scale And Community Structure Of Coral Reef Fishes: A Long-Term Study Of A Large Artificial Reef, John C. Ogden, J. P. Ebersole

Integrative Biology Faculty and Staff Publications

he fish community of a large artificial reef made In 1960 of 800 concrete blocks in a seagrass bed on the south coast of St. John, U.S. Virgin Islands, was studied by comparing a series of visual censuses (1975-1979) with each other and with a 1962 total-poison station collection (Randall, 1963). Discounting the presence of some cryptic species in the poison station that would not normally be seen in visual censuses (N = 10), as well as discounting seagrass-bed residents and roaming species only transient on the reef (N = 13), all of the censuses and the poison station (range …

Trophodynamics Of The Fish Valenciennellus Tripunctulatus Iii Energetics, Resources And Feeding Strategy, Ronald C. Baird, Thomas L. Hopkins

Marine Science Faculty Publications

A model was constructed which relates energy in diet to metabolic requirements for the mesopelagic zooplanktivore fish Valenciennellus tripunctulatus. Linear and Von Bertalanffy growth models were used to explore the energetic consequences of a number of feasible age/growth strategies. Maxlmum efficiencies were obtained with linear growth to about 30 mm in 1 y. Efficiencies declined rapidly for slower growth strategies. It was hypothesized that an 'annual' life history strategy was optimum based on energetic considerations. Copepod prey in the 1-2 mm size class were an order of magnitude more abundant and over 4 times higher in caloric content than …