Oceanography Commons^™

The Distribution Of Dissolved Barium Along The U.S. Geotraces North Atlantic Transect: Impact Of Biogeochemical Processes, Circulation And Phase Association, Karen Renee Grissom

Master's Theses

During the last four decades, since the completion of the GEOSECS program, there has been a growing interest in the biogeochemical cycle of barium (Ba) due to its potential as a proxy for interpreting the geologic record. The typical barium distribution exhibits removal in the upper water column and regeneration at depth, consistent with its classification as a bio-intermediate element and similar to the nutrient-like profiles of silicic acid and alkalinity. To better constrain the uses of Ba, trace element clean samples were collected during the North Atlantic US GEOTRACES cruises.

The cycling of barium in the North Atlantic region …

Marine Snow Settling Velocities At An Oil Spill Site And A Control Site In The Northern Gulf Of Mexico, Clayton Hugh Dike

Master's Theses

After budgeting for response efforts and natural processes, over one million barrels of oil from the BP oil spill were unaccounted for. A hypothesis coined "The Dirty Blizzard" formed subsequent to observations of large and numerous oiled marine snow aggregates amidst the surface slick proposed that a large quantity of oil sank to depth via the aggregates. Having reached the seafloor, aggregates were subject to microbial degradation and to redistribution due to bottom currents. To assist in characterizing redistribution of particles near the seafloor, sediment traps, marine snow cameras, and acoustic Doppler current profilers (ADCPs) were deployed at two sites …

Methane Dynamics In St. Louis Bay, Mississippi, Hannah Marie Roberts

Master's Theses

A method of dissolved methane analysis was developed utilizing cavity ring-down spectroscopy and headspace equilibration. Samples of 70 mL were collected in 140 mL plastic syringes and equilibrated with a methane free headspace. Reproducibility was high (i.e. 4% typical RSD), and samples were successfully measured in the low nanomolar to high micromolar range. During method development, multiple research cruises were undertaken in the northern Gulf of Mexico. Stations included the Orca Basin, the Deepwater Horizon site, and the surrounding area. The Deepwater Horizon site showed no continuing leakage from October 2010 to June 2013. Samples collected from the northern Gulf …

Effects Of Selective Grazing By Microzooplankton On Phytoplankton Composition In A Subtropical Estuary, Amanda Marie Mcgehee

Master's Theses

Rates of phytoplankton growth and microzooplankton grazing were measured at two locations within the Bay of St. Louis, MS, over the course of three months to explore the dynamics of the phytoplankton community. Community growth rates were estimated based on the changes in chlorophyll a (chl a) concentration using the dilution technique, (Landry and Hassett, 1982) and a C-specific rate was obtained using chl a labeling (Redalje and Laws, 1981). Concentrations of chl a were determined using high performance liquid chromatography (HPLC) and fluorometry. HPLC was also employed to obtain class specific growth and grazing rates, using either marker pigments …

Characterization Of Rain And Stormwater Nitrogen Inputs To The Mississippi Sound: A Landscape Approach, Joshua Michael Allen

Master's Theses

Urbanization in coastal watersheds is becoming an increasingly important issue in the world. Increased impervious surface cover, a factor of urbanization, has drawn more attention to stormwater runoff as a source of contamination to receiving waters. In this study, nitrogen species from rain and stormwater were analyzed across three different landscape types along the Mississippi Sound (hardened, residential, and pristine), as well as from drainage pipes that flow directly into to the Mississippi Sound. Nitrogen stable isotopes were used to trace the stormwater nitrogen to the surface waters and biota within the Sound.

The objective of this study was to …

Exploration Of Biophysical Interactions Associated With Mesoscale Variability In The Central Gulf Of Mexico, Katharine Celeste Woodard

Master's Theses

Bio-physical coupling in the Gulf of Mexico (GMx) is explored in this research using an integrated satellite sensor approach. Physical features are identified using Sea Level Anomaly (SLa) produced by Archiving, Validation, and Interpretation of Satellite Oceanographic data (AVISO). Biological characteristics of the GMx have been recognized as ocean color identified by the satellites SeaWiFS and MODISA. A climatology data set and a chlorophyll anomaly (CLa) was made using the 14-year mean determined from the ocean color files. The hypotheses are that there will be an inverse relationship between SLa and CLa, that mesoscale SLa features will significantly modulate local …

Testing The Limits Of Hyperspectral Airborne Remote Sensing By Mapping Eelgrass In Elkhorn Slough, Kelley J. Bostrom

Master's Theses

Seagrass ecosystems are a valuable resource, but vulnerable to changing conditions in the coastal ocean. Quantification of seagrass density and distribution from aerial imagery can be applied as a tool in resource management and ecosystem health and stability monitoring. This study investigates analytical methods for mapping eelgrass beds in an optically complex shallow, turbid estuary. Hyperspectral imagery (HSI) of Elkhorn Slough, CA was collected by the Spectroscopic Aerial Mapper with Onboard Navigation (SAMSON) instrument. In-situ data of water column and benthic optical properties and Hydrolight Radiative Transfer model were used to create a spectral library describing the reflectance of Elkhorn …

Quantification Of Nitrate Sources And Sinks Using A Water Quality Network In Morro Bay Estuary, California, Johanna Nadia Jean Weston

Master's Theses

Using an instrumented water quality network in Morro Bay Estuary, California from 2007 to 2010 (15 min sampling frequency), this study addressed the two objectives of constructing a nitrate budget and assessing the influence of sampling frequency on water quality parameters. These two objectives led to the submission of an original report of research (Appendix A) and a note (Appendix B) to peer-reviewed journals.

The first objective was to characterize the high spatial and temporal variation in physical parameters and nitrate concentrations and to construct a nitrate budget quantifying sources and sinks of nitrate from the ocean, streams, and groundwater, …

Mechanisms For Temporal Change In Phytoplankton Composition In San Luis Obispo Bay California, Marc T. Tognazzini

Master's Theses

Coastal topography and more specifically, the impact of local hydrography can significantly influence phytoplankton dynamics along the California coast. In San Luis Obispo Bay California, the local hydrography is influenced by the presence of a lee and proposed upwelling shadow in the northwest corner of the bay. These conditions allow for periods of unperturbed phytoplankton growth creating phytoplankton incubation areas. Phytoplankton dynamics including accumulation, advection, and composition were examined in San Luis Obispo Bay California from January to June 2004 using all the primary techniques of ocean monitoring encompassed in the coastal module of the Global Ocean Observing System. These …