Marine Biology Commons^™

Decadal Shifts In Biophysical Forcing Of Arctic Marine Food Webs: Numerical Consequences, John J. Walsh, Dwight A. Dieterle, Wieslaw Maslowski, Terry E. Whitledge

Marine Science Faculty Publications

Fall case studies of three‐dimensional circulation, plankton, and benthos models explored the consequences of interannual changes in ice cover and water motion on carbon/nitrogen cycling by the end of September within the Chukchi/Beaufort Seas. The coupled model scenarios were those of reduced (greater) northward flow, colder (warmer) temperatures, and more (less) extensive ice cover over the preceding ∼60 days of August and September during the negative (positive), anticyclonic (cyclonic) phase of the Arctic Oscillation in 1980 (1989). On the inner Chukchi shelf, stronger flows in 1989 advected nitrate and silicate stocks of Pacific origin ∼130 km farther northwest toward Wrangel …

A Fossil Coral Perspective On Western Tropical Pacific Climate Similar To 350 Ka, K. H. Kilbourne, Terrence M. Quinn, F. W. Taylor

Marine Science Faculty Publications

The nature of tropical climate variability ∼350 ka is addressed using δ¹⁸O and Sr/Ca records from a modern and a fossil coral from Vanuatu (southwestern tropical Pacific Ocean). Modern El Niño events at Vanuatu produce positive coral δ¹⁸O and Sr/Ca anomalies; similar anomalies observed in the fossil coral records suggest that El Niño was operative 350 kyr ago. Seasonal variations in coral Sr/Ca, a sea surface temperature (SST) proxy, have the same amplitude in both corals, whereas seasonal δ¹⁸O variations are smaller in the fossil coral than in the modern coral. This is consistent …

Interannual Volume Variability In The Tropical Pacific, Christina L. Holland, Gary T. Mitchum

Marine Science Faculty Publications

The question of whether or not the volume of the tropical Pacific changes over the course of an El Niño event has potentially important consequences for our understanding of the dynamical mechanisms responsible for El Niño‐Southern Oscillation (ENSO) events. In this study, we examine the volume variability of the tropical Pacific, defined as the areal integral of the sea surface height variability, using TOPEX/Poseidon altimetric sea surface heights and the output of a numerical model. We find that volume gradually builds up in the tropical Pacific prior to a typical ENSO event and rapidly decreases during the event due to …

Large Scale Ocean Circulation From The Grace Ggm01 Geoid, B. D. Tapley, D. Chambers, S. Bettadpur, J. C. Ries

Marine Science Faculty Publications

The GRACE Gravity Model 01 (GGM01), computed from 111 days of GRACE K-band ranging (KBR) data, is differenced from a global mean sea surface (MSS) computed from a decade of satellite altimetry to determine a mean dynamic ocean topography (DOT). As a test of the GGM01 gravity model, large-scale zonal and meridional surface geostrophic currents are computed from the topography and are compared with those derived from a mean hydrographic surface. Reduction in residual RMS between the two by 30–60% (and increased correlation) indicates that the GGM01 geoid represents a dramatic improvement over older geoid models, which were developed from …

Ocean Observer Study: A Proposed National Asset To Augment The Future U. S. Operational Satellite System, John D. Cunningham, Don P. Chambers, Curtiss O. Davis, Andrew Gerber, Rosalind Hetz, James P. Mcguire, William Pichel

Marine Science Faculty Publications

The next generation of U.S. polar orbiting environmental satellites, are now under development. These satellites, jointly developed by the Department of Defense (DoD), the Department of Commerce (DOC), and the National Aeronautics and Space Administration (NASA), will be known as the National Polar-orbiting Operational Environmental Satellite System (NPOESS). It is expected that the first of these satellites will be launched in 2010. NPOESS has been designed to meet the operational needs of the U.S. civilian meteorological, environmental, climatic, and space environmental remote sensing programs, and the Global Military Space and Geophysical Environmental remote sensing programs. This system, however, did not …

Phytoplankton Response To Intrusions Of Slope Water On The West Florida Shelf: Models And Observations, John J. Walsh, Robert H. Weisberg, Dwight A. Dieterle, Ruoying He, Brian P. Darrow, Jason K. Jolliff, Kristen M. Lester, Gabriel A. Vargo, Gary J. Kirkpatrick, Kent A. Fanning, Tracy T. Sutton, Ann E. Jochens, Douglas C. Biggs, Bisman Nababan, Chuanmin Hu, Frank E. Muller-Karger

Marine Science Faculty Publications

Previous hypotheses had suggested that upwelled intrusions of nutrient‐rich Gulf of Mexico slope water onto the West Florida Shelf (WFS) led to formation of red tides of Karenia brevis. However, coupled biophysical models of (1) wind‐ and buoyancy‐driven circulation, (2) three phytoplankton groups (diatoms, K. brevis, and microflagellates), (3) these slope water supplies of nitrate and silicate, and (4) selective grazing stress by copepods and protozoans found that diatoms won in one 1998 case of no light limitation by colored dissolved organic matter (CDOM). The diatoms lost to K. brevis during another CDOM case of the models. In …

Local And Deep-Ocean Forcing Contributions To Anomalous Water Properties On The West Florida Shelf, Robert H. Weisberg, Ruoying He

Marine Science Faculty Publications

Material property distributions on continental shelves result from the mixing and modifications of estuarine and deep-ocean source waters. How this occurs depends on the momentum and buoyancy that are input either locally on the shelf or from the deep-ocean at the shelf break. We address this question of local versus deep-ocean forcing for the West Florida Shelf (WFS) using in situ data and a numerical circulation model. The spring and summer seasons of 1998 and 1999 show distinctively different water properties on the shelf and at the shelf break. We account for these differences by a combination of local forcing, …

Millennial- To Century-Scale Variability In Gulf Of Mexico Holocene Climate Records, R. Z. Poore, H. J. Dowsett, S. Verardo, Terrence M. Quinn

Marine Science Faculty Publications

Proxy records from two piston cores in the Gulf of Mexico (GOM) provide a detailed (50–100 year resolution) record of climate variability over the last 14,000 years. Long‐term (millennial‐scale) trends and changes are related to the transition from glacial to interglacial conditions and movement of the average position of the Intertropical Convergence Zone (ITCZ) related to orbital forcing. The δ¹⁸O of the surface‐dwelling planktic foraminifer Globigerinoides ruber show negative excursions between 14 and 10.2 ka (radiocarbon years) that reflect influx of meltwater into the western GOM during melting of the Laurentide Ice Sheet. The relative abundance of the …

Chlorophyll Dispersal By Eddy-Eddy Interactions In The Gulf Of Mexico, M. Toner, A. D. Kirwan, A. C. Poje, L. H. Kantha, Frank E. Muller-Karger, C. K. R. T. Jones

Marine Science Faculty Publications

A Lagrangian analysis of the transport and dispersal of plumes observed in satellite‐derived ocean color images was conducted using a data‐assimilating model of the Gulf of Mexico. The interaction between pervasive cyclonic and anticyclonic eddies in the Gulf generated advective paths that connect remote shelf regions. These paths aligned remarkably well with the plume events recorded with the chlorophyll‐a ocean color product from SeaWiFS. Two such events were studied. In one event material was transported in a thin strip between the northern wall of the Loop Current and an adjacent cyclone, connecting the eastern Campheche shelf (off the Yucatan Peninsula) …

Evaluation Of Automated Ribotyping As A Tool For Bacterial Source Tracking In Aquatic Environments, Tracy L. Idocks

USF Tampa Graduate Theses and Dissertations

An Escherichia coli ribotype profile library was created for the Tampa Bay watershed for application to bacterial source tracking of human or non-human fecal contamination to the bay and surrounding rivers. Bacterial source tracking uses a variety of methods to identify the source of fecal contamination, not just the quantity of the indicator bacteria present, allowing implementation of effective management practices. The 700 confirmed E. coli isolate library was equally distributed among four sources: human, bird, dog and cow. The library was tested for applicability for source tracking within the Tampa Bay watershed. The DuPont Qualicon RiboPrinter® Microbial Characterization System, …

Assessment Of Current And New Methods For Investigating The Occurrence Of Enteric Pathogens In Ambient Waters And Water Sources For Rehydration Of A Floridan Wetland, Walter Quintero-Betancourt

USF Tampa Graduate Theses and Dissertations

Water quality assessment is currently used for determining the risks from contamination with waterborne pathogenic microorganisms. The public health. significance of such microorganisms cannot be fully understood without the application of reliable environmental monitoring techniques that provide efficient recovery as well as information on the infectious potential of specific isolates. This research was carried out to assess the analytical performance of current and new methods for investigating the occurrence of waterborne Cryptosporidium oocysts in samples of surface water, groundwater and reclaimed water used for public access irrigation in the State of Florida.

Method 1623 of the U.S Environmental Protection Agency …

A Loop Current Intrusion Case Study On The West Florida Shelf, Ruoying He, Robert H. Weisberg

Marine Science Faculty Publications

The Gulf of Mexico Loop Current intruded upon the West Florida continental shelf in June 2000. In situ currents and hydrography along with satellite temperature and altimetry measurements are used to describe this event and its effects on the shelf. A strong southward current is observed to flow along the shelf slope seaward of the intruded water boundary. This current transported cold, nutrient-rich water from the north, thereby producing anomalous hydrographic features near the shelf break (80-m isobath). An array of moored velocity profilers reveals that the currents landward of the intruded water are independent of the Loop Current and …

Surface And Deep Ocean Circulation In The Subpolar North Atlantic During The Mid-Pleistocene Revolution, Amy K. Wright, Benjamin P. Flower

Marine Science Faculty Publications

We investigated surface and deep ocean variability in the subpolar North Atlantic from 1000 to 500 thousand years ago (ka) based on two Ocean Drilling Program (ODP) sites, Feni drift site 980 (55°29′N, 14°42′W) and Bjorn drift site 984 (61°25′N, 24°04′W). Benthic foraminiferal stable isotope data, planktic foraminiferal faunas, ice‐rafted debris data, and faunally based sea‐surface temperature estimates help test the hypothesis that oceanographic changes in the North Atlantic region were associated with the onset of the 100‐kyr world during the mid‐Pleistocene revolution. Based on percentage of Neogloboquadrina pachyderma (s) records from both sites, surface waters during interglacials and glacials …

A Multiproxy Approach To Reconstructing Sea Surface Conditions Using Coral Skeleton Geochemistry, Terrence M. Quinn, Daniel E. Sampson

Marine Science Faculty Publications

[1] We use elemental ratio (Mg/Ca, Sr/Ca, U/Ca and Ba/Ca) and oxygen isotope data from a Porites lutea coral head collected from offshore Amedee Island, New Caledonia (22degrees29'S, 166degrees28'E) to assess the degree to which changes in these geochemical variables reflect variations in sea surface conditions. We have assessed the robustness of each geochemical proxy by comparing 25 years (1992-1968) of monthly geochemical variations with a local record of sea surface temperature (SST) and with the appropriate 1degrees by 1degrees grid box from a global gridded SST data set. We conclude from our comparison that the most consistent proxies of …

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 …

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 …

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 …

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 …

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 …

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 …

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. …

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 …

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. …

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 …

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 …

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 …