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Articles 1 - 16 of 16
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Hurricane Storm Surge Simulations Comparing Three-Dimensional With Two-Dimensional Formulations Based On An Ivan-Like Storm Over The Tampa Bay, Florida Region, Robert H. Weisberg, Lianyuan Zheng
Hurricane Storm Surge Simulations Comparing Three-Dimensional With Two-Dimensional Formulations Based On An Ivan-Like Storm Over The Tampa Bay, Florida Region, Robert H. Weisberg, Lianyuan Zheng
Marine Science Faculty Publications
We provide a dynamics‐based comparison on the results from three‐dimensional and two‐dimensional simulations of hurricane storm surge. We begin with the question, What may have occurred in the Tampa Bay, Florida vicinity had Hurricane Ivan made landfall there instead of at the border between Alabama and Florida? This question is explored using a three‐dimensional, primitive equation, finite volume coastal ocean model. The results show that storm surges are potentially disastrous for the Tampa Bay area, especially for landfalls located to the north of the bay mouth. The worst case among the simulations considered is for landfall at Tarpon Springs, such …
Si Cycle In The Cariaco Basin, Venezuela: Seasonal Variability In Silicate Availability And The Si:C:N Composition Of Sinking Particles, Robert C. Thunell, Claudia Benitez-Nelson, Frank E. Muller-Karger, Laura Lorenzoni, Mary Scranton, Ramon Varela, Yrene Astor, Kent A. Fanning
Si Cycle In The Cariaco Basin, Venezuela: Seasonal Variability In Silicate Availability And The Si:C:N Composition Of Sinking Particles, Robert C. Thunell, Claudia Benitez-Nelson, Frank E. Muller-Karger, Laura Lorenzoni, Mary Scranton, Ramon Varela, Yrene Astor, Kent A. Fanning
Marine Science Faculty Publications
A 9‐year time series of water column and sediment trap measurements was used to examine silicon cycling within the anoxic Cariaco Basin. The dynamic hydrographic regime within Cariaco Basin results in strong seasonal changes in nutrient availability and the Si:C:N of sinking particles. Upwelling in early winter injects silicic acid (Si(OH)4= ) and nitrate (NO3−) rich waters into the photic zone which stimulates primary production and results in opal fluxes in excess of 4 mmol Si m−2 d−1. However, even during upwelling, surface waters tend to be depleted (<1 μM) in …
Analysis Of Large-Scale Ocean Bottom Pressure Variability In The North Pacific, Don P. Chambers, Josh K. Willis
Analysis Of Large-Scale Ocean Bottom Pressure Variability In The North Pacific, Don P. Chambers, Josh K. Willis
Marine Science Faculty Publications
[1] We use the leading empirical orthogonal functions (EOFs) of ocean bottom pressure (OBP) derived from an ocean model and the technique of EOF reconstruction to reduce noise in the large-scale OBP variations derived from the Gravity Recovery and Climate Experiment (GRACE). The subsequent OBP variations from the model and GRACE are then examined in the North Pacific between January 2003 and May 2007. Although annual and semiannual variations are similar, GRACE observes large interannual fluctuations poleward of 30°, where OBP increases from a low of nearly 3 cm below normal in early 2003 to normal throughout 2004 and 2005, …
Grace Observes Small-Scale Mass Loss In Greenland, B. Wouters, D. Chambers, E.J. O. Schrama
Grace Observes Small-Scale Mass Loss In Greenland, B. Wouters, D. Chambers, E.J. O. Schrama
Marine Science Faculty Publications
Using satellite gravity data between February 2003 and January 2008, we examine changes in Greenland's mass distribution on a regional scale. During this period, Greenland lost mass at a mean rate of 179 ± 25 Gt/yr, equivalent to a global mean sea level change of 0.5 ± 0.1 mm/yr. Rates increase over time, suggesting an acceleration of the mass loss, driven by mass loss during summer. The largest mass losses occurred along the southeastern and northwestern coast in the summers of 2005 and 2007, when the ice sheet lost 279 Gt and 328 Gt of ice respectively within 2 months. …
Carbonatite And Silicate Melt Metasomatism Of The Mantle Surrounding The Hawaiian Plume: Evidence From Volatiles, Trace Elements, And Radiogenic Isotopes In Rejuvenated‐Stage Lavas From Niihau, Hawaii, Jacqueline Dixon, David A. Clague, Brian Cousens, Maria Luisa Monsalve, Jessika Uhl
Carbonatite And Silicate Melt Metasomatism Of The Mantle Surrounding The Hawaiian Plume: Evidence From Volatiles, Trace Elements, And Radiogenic Isotopes In Rejuvenated‐Stage Lavas From Niihau, Hawaii, Jacqueline Dixon, David A. Clague, Brian Cousens, Maria Luisa Monsalve, Jessika Uhl
Marine Science Faculty Publications
We present new volatile, trace element, and radiogenic isotopic compositions for rejuvenated‐stage lavas erupted on Niihau and its submarine northwest flank. Niihau rejuvenated‐stage Kiekie Basalt lavas are mildly alkalic and are isotopically similar to, though shifted to higher 87Sr/86Sr and lower 206Pb/204Pb than, rejuvenated‐stage lavas erupted on other islands and marginal seafloor settings. Kiekie lavas display trace element heterogeneity greater than that of other rejuvenated‐stage lavas, with enrichments in Ba, Sr, and light‐rare earth elements resulting in high and highly variable Ba/Th and Sr/Ce. The high Ba/Th lavas are among the least silica‐undersaturated of …
Estimating Geocenter Variations From A Combination Of Grace And Ocean Model Output, Sean Swenson, D. Chambers, John Wahr
Estimating Geocenter Variations From A Combination Of Grace And Ocean Model Output, Sean Swenson, D. Chambers, John Wahr
Marine Science Faculty Publications
In this study, we estimate a time series of geocenter anomalies from a combination of data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission and the output from ocean models. A matrix equation is derived relating total geocenter variations to the GRACE coefficients of degrees two and higher and to the oceanic component of the degree one coefficients. We estimate the oceanic component from t wo state-of-the-art ocean models. Results are compared to independent estimates of geocenter derived from other satellite data, such as satellite laser ranging and GPS. Finally, we compute degree one coefficients that are consistent …
Assimilation Of High-Frequency Radar Currents In A Nested Model Of The West Florida Shelf, Alexander Barth, Aida Alvera-Azcarate, Robert H. Weisberg
Assimilation Of High-Frequency Radar Currents In A Nested Model Of The West Florida Shelf, Alexander Barth, Aida Alvera-Azcarate, Robert H. Weisberg
Marine Science Faculty Publications
High‐frequency radar currents are assimilated in a West Florida Shelf (WFS) model based on the Regional Ocean Model System (ROMS), which is nested in the Atlantic Hybrid Coordinate Ocean Model (HYCOM) for the purpose of including both local and deep‐ocean forcing, particularly the Gulf of Mexico Loop Current. Tides are not included in this model. An ensemble simulation of the WFS model is carried out under different wind‐forcings in order to estimate the error covariance of the model state vector and the covariance between ocean currents and winds. Radial currents measured by high‐frequency radar antennas near Saint Petersburg and Venice, …
Assessing The Globally Averaged Sea Level Budget On Seasonal To Interannual Timescales, Josh K. Willis, D. Chambers, R Steven Nerem
Assessing The Globally Averaged Sea Level Budget On Seasonal To Interannual Timescales, Josh K. Willis, D. Chambers, R Steven Nerem
Marine Science Faculty Publications
Analysis of ocean temperature and salinity data from profiling floats along with satellite measurements of sea surface height and the time variable gravity field are used to investigate the causes of global mean sea level rise between mid-2003 and mid-2007. The observed interannual and seasonal fluctuations in sea level can be explained as the sum of a mass component and a steric (or density related) component to within the error bounds of each observing system. During most of 2005, seasonally adjusted sea level was approximately 5 mm higher than in 2004 owing primarily to a sudden increase in ocean mass …
A Nested Model Study Of The Loop Current Generated Variability And Its Impact On The West Florida Shelf, Alexander Barth, Aida Alvera-Azcarate, Robert H. Weisberg
A Nested Model Study Of The Loop Current Generated Variability And Its Impact On The West Florida Shelf, Alexander Barth, Aida Alvera-Azcarate, Robert H. Weisberg
Marine Science Faculty Publications
A West Florida Shelf model based on the Regional Ocean Modeling System (ROMS) is nested in the North Atlantic Hybrid Coordinate Ocean Model (NAT HYCOM). The focus of this work is the study of the impact of the Loop Current on the West Florida Shelf. In order to assess the model's accuracy, it is compared quantitatively to in situ temperature and velocity measurements on the shelf. A series of sensitivity experiments are conducted to determine the appropriate wind forcing, sea surface temperature relaxation, and mixing scheme. by the inclusion of the Loop Current, we are able to study the propagation …
Changes Of Temperature And Bio-Optical Properties In The South China Sea In Response To Typhoon Lingling, 2001, Shaoling Shang, Li Li, Fengqin Sun, Jingyu Wu, Chuanmin Hu, Dewen Chen, Xiuren Ning, Yun Qiu, Caiyun Zhang, Shaoping Shang
Changes Of Temperature And Bio-Optical Properties In The South China Sea In Response To Typhoon Lingling, 2001, Shaoling Shang, Li Li, Fengqin Sun, Jingyu Wu, Chuanmin Hu, Dewen Chen, Xiuren Ning, Yun Qiu, Caiyun Zhang, Shaoping Shang
Marine Science Faculty Publications
A large patch of enhanced chlorophyll a concentration (Chla), lower sea surface temperature (SST), and lower sea surface height (SSH) was revealed in the central South China Sea (SCS) in November 2001 after the passage of typhoon Lingling. Maximum SST reduction of 11°C occurred one day after Lingling's passage on 11/11. Subsequently, against a background level of 0.08 mg/m3, average Chla within the area of 12.60–16.49°N, 112.17–117.05°E increased to 0.14 mg/m3 on 11/12 and then to 0.37 mg/m3 on 11/14. Dissolved organic matter and detritus were differentiated from Chla using a recent bio-optical algorithm. They contributed …
Middle Miocene Ice Sheet Dynamics, Deep‐Sea Temperatures, And Carbon Cycling: A Southern Ocean Perspective, Amelia E. Shevenell, James P. Kennett, David W. Lea
Middle Miocene Ice Sheet Dynamics, Deep‐Sea Temperatures, And Carbon Cycling: A Southern Ocean Perspective, Amelia E. Shevenell, James P. Kennett, David W. Lea
Marine Science Faculty Publications
Relative contributions of ice volume and temperature change to the global ∼1‰ δ18O increase at ∼14 Ma are required for understanding feedbacks involved in this major Cenozoic climate transition. A 3‐ma benthic foraminifer Mg/Ca record of Southern Ocean temperatures across the middle Miocene climate transition reveals ∼2 ± 2°C cooling (14.2–13.8 Ma), indicating that ∼70% of the increase relates to ice growth. Seawater δ18O, calculated from Mg/Ca and δ18O, suggests that at ∼15 Ma Antarctica's cryosphere entered an interval of apparent eccentricity‐paced expansion. Glaciations increased in intensity, revealing a central role for internal climate …
Metagenomic Analysis Of Lysogeny In Tampa Bay: Implications For Prophage Gene Expression, Lauren D. Mcdaniel, Mya Breitbart, Jennifer M. Mobberley, Amy Long, Matthew Haynes, Forest Rohwer, John Paul
Metagenomic Analysis Of Lysogeny In Tampa Bay: Implications For Prophage Gene Expression, Lauren D. Mcdaniel, Mya Breitbart, Jennifer M. Mobberley, Amy Long, Matthew Haynes, Forest Rohwer, John Paul
Marine Science Faculty Publications
Phage integrase genes often play a role in the establishment of lysogeny in temperate phage by catalyzing the integration of the phage into one of the host's replicons. To investigate temperate phage gene expression, an induced viral metagenome from Tampa Bay was sequenced by 454/Pyrosequencing. The sequencing yielded 294,068 reads with 6.6% identifiable. One hundred-three sequences had significant similarity to integrases by BLASTX analysis (e≤0.001). Four sequences with strongest amino-acid level similarity to integrases were selected and real-time PCR primers and probes were designed. Initial testing with microbial fraction DNA from Tampa Bay revealed 1.9×107, and 1300 gene …
A New Bathymetric Compilation Highlighting Extensive Paleo–Ice Sheet Drainage On The Continental Shelf, South Georgia, Sub-Antarctica, Alastair G. C. Graham, Peter T. Fretwell, Robert D. Larter, Dominic A. Hodgson, Christian K. Wilson, Alex J. Tate, Peter Morris
A New Bathymetric Compilation Highlighting Extensive Paleo–Ice Sheet Drainage On The Continental Shelf, South Georgia, Sub-Antarctica, Alastair G. C. Graham, Peter T. Fretwell, Robert D. Larter, Dominic A. Hodgson, Christian K. Wilson, Alex J. Tate, Peter Morris
Marine Science Faculty Publications
A grid derived from a new compilation of marine echo-sounding data sets has allowed us to visualize and map the geomorphology of the entire continental shelf around South Georgia at an unprecedented level of detail. The grid is the first continuous bathymetric data set covering South Georgia to include multibeam swath bathymetry and represent them at a subkilometer resolution. Large and previously undescribed glacially eroded troughs, linked to South Georgia's modern-day fjords, radiate from the island, marking the former pathways of large outlet glaciers and ice streams. A tectonic or geological influence is apparent for the major troughs, where glaciers …
A Bacterial Metapopulation Adapts Locally To Phage Predation Despite Global Dispersal, Victor Kunin, Shaomei He, Falk Warnecke, S. Brook Peterson, Hector Garcia Martin, Matthew Haynes, Natalia Ivanova, Linda Blackall, Mya Breitbart, Forest Rohwer, Katherine Mcmahon, Philip Hugenholtz
A Bacterial Metapopulation Adapts Locally To Phage Predation Despite Global Dispersal, Victor Kunin, Shaomei He, Falk Warnecke, S. Brook Peterson, Hector Garcia Martin, Matthew Haynes, Natalia Ivanova, Linda Blackall, Mya Breitbart, Forest Rohwer, Katherine Mcmahon, Philip Hugenholtz
Marine Science Faculty Publications
Using a combination of bacterial and phage-targeted metagenomics, we analyzed two geographically remote sludge bioreactors enriched in a single bacterial species Candidatus Accumulibacter phosphatis (CAP). We inferred unrestricted global movement of this species and identified aquatic ecosystems as the primary environmental reservoirs facilitating dispersal. Highly related and geographically remote CAP strains differed principally in genomic regions encoding phage defense mechanisms. We found that CAP populations were high density, clonal, and nonrecombining, providing natural targets for “kill-the-winner” phage predation. Community expression analysis demonstrated that phages were consistently active in the bioreactor community. Genomic signatures linking CAP to past phage exposures were …
Antarctic Sediment Chronology By Programmed-Temperature Pyrolysis: Methodology And Data Treatment, Brad E. Rosenheim, Mary Beth Day, Eugene Domack, Heather Schrum, Albert Benthien, John M. Hayes
Antarctic Sediment Chronology By Programmed-Temperature Pyrolysis: Methodology And Data Treatment, Brad E. Rosenheim, Mary Beth Day, Eugene Domack, Heather Schrum, Albert Benthien, John M. Hayes
Marine Science Faculty Publications
We report a detailed programmed-temperature pyrolysis/combustion methodology for radiocarbon (14C) dating of Antarctic sub-ice shelf sediments. The method targets the autochthonous organic component in sediments that contain a distribution of acid-insoluble organic components from several sources of different ages. The approach has improved sediment chronology in organic-rich sediments proximal to Antarctic ice shelves by yielding maximum age constraints significantly younger than bulk radiocarbon dates from the same sediment horizons. The method proves adequate in determining isotope ratios of the pre-aged carbon end-member; however, the isotopic compositions of the low-temperature measurements indicate that no samples completely avoided mixing with some proportion …
Morphology And Filling Of Incised Submarine Valleys On The Continental Shelf Near The Mouth Of The Fly River, Gulf Of Papua, J. S. Crockett, C. A. Nittrouer, A. S. Ogston, D. F. Naar, B. T. Donahue
Morphology And Filling Of Incised Submarine Valleys On The Continental Shelf Near The Mouth Of The Fly River, Gulf Of Papua, J. S. Crockett, C. A. Nittrouer, A. S. Ogston, D. F. Naar, B. T. Donahue
Marine Science Faculty Publications
Much historical perspective about terrestrial and marine processes can be obtained from examination of fluvial valleys formed during lower sea level on surfaces that are now continental shelves. The continental shelf near the mouth of the Fly River (Gulf of Papua) has three incised valleys, which were not extensively modified or filled during the Holocene Transgression. Multibeam mapping of the valleys documents their morphology; seismic profiling reveals stratigraphy of sediment fill; and coring within and near the valleys suggests mechanisms of filling. Kiwai Valley is deep (20–50 m relief), narrow (∼1 km wide), steep-sided and meandering, due to river flows …