Life Sciences Commons^™

Hydrothermal Venting Along Earth's Fastest Spreading Center: East Pacific Rise, 27.5°–32.3°, E. T. Baker, R. N. Hey, J. E. Lupton, J. A. Resing, R. A. Feely, J. J. Gharib, G. J. Massoth, F. J. Sansone, M. Kleinrock, F. Martinez, D. F. Naar, C. Rodrigo, D. Bohnenstiehl, D. Pardee

Marine Science Faculty Publications

During March/April 1998 we conducted detailed mapping and sampling of hydrothermal plumes along six segments of Earth's fasting spreading mid-ocean ridge, 27.5°–32.3°S on the East Pacific Rise. We compared the distribution and chemistry of hydrothermal plumes to geological indicators of long-term (spreading rate) and moderate-term (ridge inflation) variations in magmatic budget. In this large-offset, propagating rift setting, these geological indices span virtually the entire range found along fast spreading ridges worldwide. Hydrothermal plumes overlaid ∼60% of the length of superfast (>130 km/Myr) spreading axis surveyed and defined at least 14 separate vent fields. We observed no plumes over the …

West Florida Shelf Response To Local Wind Forcing: April 1998, Robert H. Weisberg, Zhenjiang Li, Frank E. Muller-Karger

Marine Science Faculty Publications

We compare west Florida shelf velocity and sea level data with a model simulation for April 1998. Responses for three upwelling and three downwelling favorable wind events are documented. Along-shelf jets accompanied by oppositely directed upper and lower layer across-shelf flows (with connecting vertical velocity) comprise the fully three-dimensional inner shelf responses, which are sensitive to stratification. With an initial density field representative of April 1998 the model simulates velocity and sea level variations in general agreement with the observations, whereas substantial mismatches occur without stratification. Despite the winds being the primary motive agent for the inner shelf the stratification …

The Effect Of Mulching On Herbaceous Wetland Creation Areas In West-Central Florida, Christopher J. Anderson

USF Tampa Graduate Theses and Dissertations

Wetland mulching is the transfer of soil (often from a wetland area which is going to filled or otherwise impacted) on to the surface of a wetland creation area. The primary intent of mulching is to transfer wetland vegetation in the form of seeds and propagules, from the natural wetland to the creation area. This technique also is used to transfer organic matter and microbial fauna existing in the soil to the creation area. My study examines the effects that wetland mulching has on: 1) percent organic matter in the soil, 2) the wetland affinity of plant communities present, 3) …

Ocean Drilling Constrains Carbonate Platform Formation And Miocene Sea Level On The Australian Margin, Alexandra R. Isern, F. S. Anselmetti, P. Blum, Shipboard Scientific Party

Marine Science Faculty Publications

Carbonate platforms are large geologic structures composed of the remains of formerly living, calcium carbonate‐secreting organisms that can develop in environments ranging from tropical to temperate, and in locations that are free of siliceous sediment to those with significant amounts of sediment from land. Because these platforms are composed of biogenic remains sensitive to changes in environmental conditions such as sea level, wind or currents, nutrient content, and water temperature, the study of carbonate platforms provides fundamental information regarding environmental change in a range of environments. In addition to their high‐quality environmental record, carbonate platforms are often important petroleum reservoirs. …

Ocean Circulation Influences On Sea Surface Temperature In The Equatorial Central Pacific, Chunzai Wang, Robert H. Weisberg

Marine Science Faculty Publications

Velocity data from an array of acoustic Doppler current profilers moored about 0°, 140°W from May 1990 through June 1991 during the Tropical Instability Wave Experiment are used in conjunction with Tropical Atmosphere‐Ocean array data and a blended sea surface temperature (SST) product to study the processes that control SST variations. The horizontal velocity data allow us to calculate the vertical velocity component by vertically integrating the continuity equation. Given the three‐dimensional temperature flux divergence, we examine the role of the ocean circulation in SST. Upwelling and downwelling are found to be associated with cooling and warming, respectively, suggesting that …

The Foraging Ecology Of The Juvenile Gopher Tortoise, Gopheruspol Yphemus, Terri Anne Stilson

USF Tampa Graduate Theses and Dissertations

Food plant preferences of juvenile gopher tortoises, Gopherus polyphemus, were investigated in a west central Florida population. The juvenile gopher tortoises were free-ranging and were located in a sandhill habitat subject to yearly prescribed burns. Diet was determined by foraging observations, in which the number of bites taken per taxon, the number of plants sampled per taxon, and the amount of each taxon available along the foraging path were recorded. Preference was determined with Manly's alpha index of preference and Jacob's D electivity index. Selected plants in the habitat were analyzed for relative nitrogen content to investigate whether preferred …

Properties Of The Water Column And Bottom Derived From Airborne Visible Infrared Imaging Spectrometer (Aviris) Data, Zhongping Lee, Kendall L. Carder, Robert F. Chen, Thomas G. Peacock

Marine Science Faculty Publications

Using Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data as an example, we show in this study that the properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used to derive concentrations of chlorophyll, dissolved organic matter, and suspended sediments in the water column. The derived bottom depths were compared with a bathymetry chart and a boat survey and were found to agree very well. Also, the derived bottom …

Saharan Dust And Florida Red Tides: The Cyanophyte Connection, John J. Walsh, Karen A. Steidinger

Marine Science Faculty Publications

Prediction of the consequences of harmful algal blooms for humans and other vertebrates is constrained by an inadequate understanding of the factors that promote their initiation. A simple exponential growth model of net production is used for analysis of four time series at different sampling intervals over similar to 40 years of red tide strandings, associated fish kills, and concomitant dust loadings on the West Florida shelf. at least large summer blooms of a toxic dinoflagellate Gymnodinium breve appear to be primed regularly by an aeolian supply of nutrients. Wet deposition of Saharan mineral aerosols may alleviate iron limitation of …

Equatorial Upwelling In The Western Pacific Warm Pool, Robert W. Helber, Robert H. Weisberg

Marine Science Faculty Publications

Vertical velocity on the equator in the western Pacific warm pool is investigated using data from the Coupled Ocean‐Atmosphere Response Experiment enhanced monitoring array (EMA) centered at 0°, 156°E. The data consist of hourly subsurface horizontal velocity time series from August 1991 until April 1994. Vertical velocity is calculated using horizontal velocity components and the application of the continuity equation. During the first year, from March 1992 until February 1993, data are available from five moorings of the EMA and thus provide nine different combinations of moorings from which to calculate vertical velocity. Four moorings were available during the remaining …

Response Of The Threatened Sand Skink (Neoseps Reynolds!) And Other Herpetofaunal Species To Burning And Clearcutting In The Florida Sand Pine Scrub Habitat, Kristie D. Gianopulos

USF Tampa Graduate Theses and Dissertations

Florida scrub habitat is a naturally fire maintained habitat that is highly endangered because of great demand for land for agriculture and real estate. Maintenance of remaining patches ofFlorida scrub habitat requires active management. We experimentally investigated the effects of clearcutting and burning on sand skink populations in three patches of sand pine scrub. Each patch included a clearcut plot, a burned plot, and an undisturbed plot. Treatment plot boundaries were drawn in 1995 such that each plot was no different from any other plot in sand skink densities. The responses of sand skink and other herpetofauna populations were monitored …

Hydrography, Nutrients, And Carbon Pools In The Pacific Sector Of The Southern Ocean: Implications For Carbon Flux, Kendra L. Daly, Walker O. Smith, Gregory C. Johnson, Giacomo R. Ditullio, David R. Jones, Calvin W. Mordy, Richard A. Feely, Dennis A. Hansell, Jia-Zhong Zhang

Marine Science Faculty Publications

We investigated the hydrography, nutrients, and dissolved and particulate carbon pools in the western Pacific sector of the Antarctic Circumpolar Current (ACC) during austral summer 1996 to assess the region's role in the carbon cycle. Low fCO(2) values along two transects indicated that much of the study area was a sink for atmospheric CO2. The fCO(2) values were lowest near the Polar Front (PF) and the Subtropical Front (STF), concomitant with maxima of chlorophyll a and particulate and dissolved organic carbon. The largest biomass accumulations did not occur at fronts, which had high surface geostrophic velocities (20-51 cm s(-1)), but …

Annual Cycle Of Primary Production In The Cariaco Basin: Response To Upwelling And Implications For Vertical Export, Frank E. Muller-Karger, Ramon Varela, Robert Thunell, Mary Scranton, Richard Bohrer, Gordon Taylor, Juan Capelo, Yrene Astor, Eric Tappa, Tung-Yuan Ho, John J. Walsh

Marine Science Faculty Publications

Monthly hydrographic, primary production, bacterial production, and settling particulate carbon flux observations were collected between November 1995 and December 1997 at 10.5 degreesN, 64.67 degreesW within the Cariaco Basin, off Venezuela. Upwelling of Subtropical Underwater (SUW) started around October and lasted through approximately May of the following year. Wind speeds >7 m s(-1) were observed between January and June, with weaker winds (s(-1)) between July and December. The upwelling cycle was therefore out of phase with that of the trade winds by 2-3 months. A seasonal cycle punctuated by transient extremes associated with subsurface ventilation events was observed in primary …

Enso Influences On Seasonal Rainfall And River Discharge In Florida, Nancy Schmidt, E. K. Lipp, J. B. Rose, Mark E. Luther

Marine Science Faculty Publications

Hemispherical and regional analyses of climatic patterns relating to El Niño–Southern Oscillation (ENSO) indicate strong responses in the southeastern United States, especially during the wintertime. Using Florida as an example, the authors focused on local-scale patterns within this region in order to examine the geographic variability of seasonal rainfall and river discharge as related to ENSO. Forty-eight years (1950–98) of precipitation and river discharge data in Florida were classified, using sea surface temperature anomaly data from the equatorial Pacific Ocean, as occurring during an El Niño (warm event), La Niña (cold event), or neither (neutral). Seasonal precipitation and streamflow both …

Propagation Of Big Island Eddies, Christina L. Holland, Gary T. Mitchum

Marine Science Faculty Publications

Using satellite altimetry data, we have observed a series of anticyclonic eddies as they form at the Big Island of Hawaii and have tracked them as they move away from the island. While similar eddies have been observed near the Hawaiian Islands in previous studies, the fate of the anticyclonic eddies has previously been unclear. The eddies that we observed initially propagated to the southwest but consistently changed propagation direction to the northwest later in their lifetimes. This was intriguing to us, as theoretically, the decay of isolated anticyclonic eddies on a β plane should cause them to continually move …

Statistical Self-Similarity Of Hotspot Seamount Volumes Modeled As Self-Similar Criticality, S. F. Tebbens, S. M. Burroughs, C. C. Barton, D. F. Naar

Marine Science Faculty Publications

The processes responsible for hotspot seamount formation are complex, yet the cumulative frequency-volume distribution of hotspot seamounts in the Easter Island/Salas y Gomez Chain (ESC) is found to be well-described by an upper-truncated power law. We develop a model for hotspot seamount formation where uniform energy input produces events initiated on a self-similar distribution of critical cells. We call this model Self-Similar Criticality (SSC). By allowing the spatial distribution of magma migration to be self-similar, the SSC model recreates the observed ESC seamount volume distribution. The SSC model may have broad applicability to other natural systems.

Caustic Consideration Of Long Planetary Wave Packet Analysis In The Continuously Stratified Ocean, Arthur D. Gorman, Huijun Yang

Marine Science Faculty Publications

The wave packet method, one form of the WKB technique, recently has been employed to investigate the evolution of long planetary wave packets in relation to the complex climate variability in the world oceans. However, such a method becomes invalid near the caustics. Here, the Lagrange manifold formalism is used to extend this analysis to include the caustic regions. We conclude that even though the wave packet method fails near the caustics, the equations derived from this method away from caustics are identical to ones from the Lagrange manifold formalism near caustics

Equatorial Inertia‐Gravity Waves Observed In Topex/Poseidon Sea Surface Heights, Sherryl Gilbert, Gary Mitchum

Marine Science Faculty Publications

We report an evaluation of the ability of the TOPEX/Poseidon altimeter to observe equatorial inertia‐gravity waves in the central Pacific. Aliasing problems limit us to examining meridional mode two, but this mode is an energetic one in the Pacific basin. These estimates of the temporal potential energy modulations are compared with estimates from tide gauges in the tropical Pacific, and we find that the time series obtained at these points show good agreement.

Appendix: Magnetic Experiments, M. Fuller, Y. Touchard, C. Endris, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

During Leg 189, magnetic experiments were continued in an attempt to understand and mitigate the troublesome magnetic overprints encountered in the paleomagnetism of recovered Ocean Drilling Program (ODP) sediment cores. Although these overprints do not interfere with magnetostratigraphy, except at low-latitude sites, they degrade some records sufficiently that the potentially invaluable reversal and secular variation records in the cores are not usable for high-resolution work. A nonmagnetic advanced hydraulic piston core (APC) barrel assembly was run on alternate APC cores throughout the leg, and the results from cores obtained with it were compared with those cored with the standard assembly. …

Site 1169, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

No abstract provided.

The Tasmanian Gateway: Cenozoic Climatic And Oceanographic Development, Neville F. Exon, James P. Kennett, Mitchell J. Malone, Henk Brinkhuis, George C.H. Chaproniere, Atsuhito Ennyu, Amelia E. Shevenell

Marine Science Faculty Publications

No abstract provided.

Leg 189 Summary, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

The Cenozoic Era is unusual in its development of major ice sheets. Progressive high-latitude cooling during the Cenozoic eventually formed major ice sheets, initially on Antarctica and later in the Northern Hemisphere. In the early 1970s, a hypothesis was proposed that climatic cooling and an Antarctic cryosphere developed as the Antarctic Circumpolar Current progressively thermally isolated the Antarctic continent. This current resulted from the opening of the Tasmanian Gateway south of Tasmania during the Paleogene and the Drake Passage during the earliest Neogene.

The five Leg 189 drill sites, in 2463 to 3568 m water depths, tested, refined, and extended …

Site 1170, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

No abstract provided.

Site 1171, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

No abstract provided.

Site 1172, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

No abstract provided.

Site 1168, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

No abstract provided.

Explanatory Notes, Shipboard Scientific Party, Amelia E. Shevenell

Marine Science Faculty Publications

This chapter explains the techniques and procedures used during Leg 189 to help document the basis for our preliminary scientific conclusions and to provide the interested investigator with the information needed to select samples for further analysis. This information concerns only shipboard operations and analyses described in the site reports in the Leg 189 Initial Reports volume of the Proceedings of the Ocean Drilling Program. The methods used by various investigators for shore-based analyses of Leg 189 data will be described in the individual scientific contributions published in the Scientific Results volume and in publications in various professional journals.

Coherence Of Internal Tide Modulations Along The Hawaiian Ridge, Gary T. Mitchum, Stephen M. Chiswell

Marine Science Faculty Publications

Long time series of sea level from tide gauges along the north side of the Hawaiian Ridge and shorter series of dynamic heights inferred from inverted echo sounders moored just north of the main Hawaiian Islands are examined for evidence of internal tides at the M₂ frequency. We find that the amplitudes and phases of the M₂ tidal components have low-frequency variability, which is consistent with a superposition of an internal tide with the larger barotropic tide. Further, the low-frequency variability is correlated with low-frequency changes in the depth of the pycnocline, which suggests a simple physical mechanism …

Meeting Explores Sensor Technology For Remote, Interactive Aquatic Experiments, Kendra L. Daly

Marine Science Faculty Publications

Oceans, lakes, rivers, and groundwater are complex, dynamic environments in which physical, chemical, and biological processes occur over varying temporal and spatial scales (e.g., eddies, nutrient fluxes, patchiness of organisms, benthic processes, and pollution). In addition, deep, remote, or hostile systems such as hydrothermal vents and polar regions traditionally are poorly sampled, but are important to understanding global biogeochemical and hydrological cycles. In the coming decades, moored, cabled, and autonomous observatories will be used to investigate a spectrum of basic processes in aquatic environments. In anticipation of the need to develop or re‐engineer sensors to measure physical, chemical, biological, and …

Orbitally Induced Climate And Geochemical Variability Across The Oligocene/Miocene Boundary, Hilary A. Paul, James C. Zachos, Benjamin P. Flower, Aradhna Tripati

Marine Science Faculty Publications

To assess the influence of orbital-scale variations on late Oligocene to early Miocene climate and ocean chemistry, high-resolution (similar to 5 kyr) benthic foraminiferal carbon and oxygen isotope and percent coarse fraction time series were constructed for Ocean Drilling Program site 929 on Ceara Rise in the western equatorial Atlantic. These time series exhibit pervasive low- to high-frequency variability across a 5-Myr interval (20.5-25.4 Ma). The records also reveal several large-scale secular variations including two positive (similar to 1.6 parts per thousand) oxygen isotope excursions at 22.95 and 21.1 Ma, suggestive of large but brief glacial maxima (Mi-l and Mi-la …

North Atlantic Intermediate To Deep Water Circulation And Chemical Stratification During The Past 1 Myr, Benjamin P. Flower, D. W. Oppo, J. F. Mcmanus, K. A. Venz, D. A. Hodell, J. L. Cullen

Marine Science Faculty Publications

Benthic foraminiferal carbon isotope records from a suite of drill sites in the North Atlantic are used to trace variations in the relative strengths of Lower North Atlantic Deep Water (LNADW), Upper North Atlantic Deep Water (UNADW), and Southern Ocean Water (SOW) over the past 1 Myr. During glacial intervals, significant increases in intermediate-to-deep delta(13)C gradients (commonly reaching >1.2 parts per thousand) are consistent with changes in deep water circulation and associated chemical stratification. Bathymetric delta(13)C gradients covary with benthic foraminiferal delta(18)O and covary inversely with Vostok CO2, in agreement with chemical stratification as a driver of atmospheric CO2 changes. …