Oceanography Commons^™

Analysis Of Vector Sensor Data Collected In Gulf Of Mexico, Timothy S. Vann

LSU New Orleans Theses and Dissertations

In 2015, the Naval Oceanographic Office collected vector sensor data in approximately 100 meters of water southwest of Panama City, Florida in the Gulf of Mexico. The vector sensor was deployed at a center mass height of one foot above the seafloor and de-coupled from its mooring through lightweight springs to measure local acoustical pressure and particle velocity.

Accuracy of the data across frequency and source azimuth is measured by evaluating acoustical impedance as a function of frequency and source azimuthal direction. Results indicate the vector sensor has an effective band from 50 to 450 Hz with mooring reflections and …

Toward Near‐Field Tsunami Forecasting Along The Cascadia Subduction Zone Using Rapid Gnss Source Models, Amy L. Williamson, Diego Melgar, Brendan W. Crowell, Diego Argas, Timothy I. Melbourne, Yong Wei, Kevin Kwong

Geological Sciences Faculty Scholarship

Over the past 15 years and through multiple large and devastating earthquakes, tsunami warning systems have grown considerably in their efficacy in providing timely and accurate forecasts to affected communities. However, one part of tsunami warning that still needs improvement is forecasts catered to local, near‐field communities in the time after an earthquake rupture but before coastal inundation. In this study, we test a rapid, Global Navigation Satellite Systems (GNSS)‐driven earthquake characterization model using a large data set of synthetic megathrust ruptures for its near‐field tsunami forecasting potential. We also provide a framework for tsunami forecasting that focuses on the …

Prioritizing The Largest, Oldest Corals For Disease Intervention In A Coral Disease-Ravaged Area: Southeast Florida Coral Reef Ecosystem Conservation Area, Alysha Brunelle

All HCAS Student Capstones, Theses, and Dissertations

Coral diseases appear to be more devastating than ever before. When a virulent disease ravages a coral ecosystem, it can significantly change the population’s demographics and cause local extinctions. Disease intervention response during such an event is impossible at a landscape scale, therefore priorities must be considered. Saving the largest, oldest colonies of reef-building species is a good choice due to their high fecundity and ecological function. Their size, as a proxy for age, is an indicator of their resistance to previous perturbations which may indicate higher fitness. Their size also provides habitat to many organisms and wave resistance in …

The Source Detection Of 28 September 2018 Sulawesi Tsunami By Using Ionospheric Gnss Total Electron Content Disturbance, Jann-Yenq Liu, Chi-Yen Lin, Yuh-Ing Chen, Tso-Ren Wu, Meng-Ju Chung, Tien-Chi Liu, Yu-Lin Tsai, Loren C. Chang, Chi-Kuang Chao, Dimitar Ouzounov, Katsumi Hattori

Mathematics, Physics, and Computer Science Faculty Articles and Research

The 28 September 2018 magnitude Mw7.8 Palu, Indonesia earthquake (0.178° S, 119.840° E, depth 13 km) occurred at 10:02 UTC. The major earthquake triggered catastrophic liquefaction, landslides, and a near-field tsunami. The ionospheric total electron content (TEC) derived from records of 5 ground-based global navigation satellite system (GNSS) receivers is employed to detect tsunami traveling ionospheric disturbances (TTIDs). In total, 15 TTIDs have been detected. The ray-tracing and beamforming techniques are then used to find the TTID source location. The bootstrap method is applied in order to further explore the possible location of the tsunami source based on results of …

Algal Coverage Detection And Classification Using Envi: Correlation With Dissolved Oxygen Levels In Elkhorn Slough, Ca, Jason Dawson

All HCAS Student Capstones, Theses, and Dissertations

Estuaries are exposed to varying stressors, whether they be physical, chemical, or environmental. The most notable of stressors is eutrophication of coastal and inland ecosystems. This is a result of increased supply of nutrients fueling production within the system. One outcome of this increased nutrient load to the system is that of algal blooms. These blooms can impact the aesthetic appearance and degrade the quality of health of the system. Many of these coastal zones and waterways are critical habitats for many biological (some endangered) species and serve as recreational areas for human populations. Elkhorn Slough, California is one of …

Bonnet Carré Spillway Freshwater Transport And Corresponding Biochemical Properties In The Mississippi Bight, Sabrina M. Parra, Virginie Sanial, Adam D. Boyette, M. Kemal Cambazoglu, Inia M. Soto, Adam T. Greer, Luciano M. Chiaverano, Angie Hoover, Michael S. Dinniman

CCPO Publications

Large freshwater pulses to coastal ecosystems change local hydrologic regimes and alter biogeochemical processes. The Mississippi Bight coastal ecosystem, located in the northern Gulf of Mexico shelf, is influenced by extensive freshwater inputs: the Mississippi River (MSR) and several smaller rivers to the east. Under river flood conditions, MSR waters flow through the Bonnet Carré Spillway (BCS) to relieve pressure on levees in New Orleans, Louisiana. In 2015, mild wintertime temperatures and heavy rainfall throughout the MSR watershed led to extreme flooding and prompted an unusually early BCS opening on January 10, 2016 for 23 days. This study examines the …

Freshwater Endmembers Impacting Carbonate Chemistry In The Mississippi Sound, Allison Savoie

Master's Theses

Coastal ecosystems are highly dynamic areas for carbon cycling and are likely to be negatively impacted by increasing ocean acidification. This research focused on dissolved inorganic carbon (DIC) and total alkalinity (TA) in the Mississippi Sound in order to understand the influence of local rivers that supply alkalinity to the area and buffer against ocean acidification. This area receives large fluxes of freshwater from local rivers, in addition to episodic inputs from the Mississippi River through a human-built diversion, the Bonnet Carré Spillway. Sites in the Mississippi Sound were sampled monthly during August 2018 to November 2019 and at weekly …

Using Disruptive Coloration And Ultraviolet Light To Prevent Barnacle Settlement, Kailey Nicole Richard

Theses and Dissertations

Biofouling or the accumulation of unwanted micro and macro organisms is problematic for the shipping industry. Barnacles are one of the most abundant fouling organisms and their settlement on ship hulls can result in costly damage. Several methods have been developed to prevent the formation of biofouling, including antifouling coatings and mechanical techniques, but the search for more effective and environmentally friendly solutions is still ongoing. This thesis investigated two methods aimed at barnacle prevention: color patterning and the application of ultraviolet light. The first method utilized disruptive coloration, a common mechanism observed in nature by terrestrial organisms (i.e. butterflies) …

Organic Sediment Impacts On Seagrasses And Their Associations With Benthic Fauna, Sean Matthew Crowley

Theses and Dissertations

Human-population growth and rapid rates of urbanization have led to eutrophic conditions in estuaries throughout the world. Effects often include severe algal blooms, decreased dissolved oxygen levels, and the accumulation of fine-grained organic-rich sediments. One frequent negative consequence of eutrophication is the decline of seagrasses, a vital component of coastal ecosystems. Seagrasses provide shelter from predation, serve as nursery habitat, stabilize sediments, act as a sink for excess carbon, produce oxygen, and are a food source for many herbivores. Seagrasses are also sensitive to environmental changes, such as declining water quality and increased sedimentation rates. This study examines the impacts …

Statement Of World Aquatic Scientific Societies On The Need To Take Urgent Action Against Human-Caused Climate Change, Based On Scientific Evidence [Dear Colleague Letter], Scott A. Bonar, Brian R. Murphy, Leanne H. Roulson, Jesse T. Trushenski, Douglas J. Austen, Michael Edward Douglas

United States Fish and Wildlife Service: Publications

Dear Colleague Letter from the American Fisheries Society to fellow scientific societies, July 25, 2020, about the urgent need for responsive collective action to mitigate impending radical climate change. Includes the Statement of World Aquatic Scientific Societies on the Need to Take Urgent Action Against Human-Caused Climate Change, Based on Scientific Evidence, emphasizing the importance of aquatic ecosystems. Includes extensive citations and notes.

"Water is the most important natural resource on Earth as it is vital for life. Aquatic ecosystems, freshwater or marine, provide multiple benefits to human society, such as provisioning of oxygen, food, drinking water, genetic resources; regulation …

Global Atmospheric Budget Of Acetone: Air-Sea Exchange And The Contribution To Hydroxyl Radicals, Siyuan Wang, Eric C. Apel, Rebecca H. Schwantes, Kelvin H. Bates, Daniel J. Jacob, Emily V. Fischer, Rebecca S. Hornbrook, Alan J. Hills, Louisa K. Emmons, Laura L. Pan, Shawn Honomichl, Simone Tilmes, Jean‐François Lamarque, Mingxi Yang, Christa A. Marandino, E. S. Saltzman, Warren J. De Bruyn, Sohiko Kameyama, Hiroshi Tanimoto, Yuko Omori, Samuel R. Hall, Kirk Ullmann, Thomas B. Ryerson, Chelsea R. Thompson, Jeff Peischl, Bruce C. Daube, Róisín Commane, Kathryn Mckain, Colm Sweeney, Alexander B. Thames, David O. Miller, William H. Brune, Glenn S. Diskin, Joshua P. Digangi, Steven C. Wofsy

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Acetone is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere. The oceans impose a strong control on atmospheric acetone, yet the oceanic fluxes of acetone remain poorly constrained. In this work, the global budget of acetone is evaluated using two global models: CAM‐chem and GEOS‐Chem. CAM‐chem uses an online air‐sea exchange framework to calculate the bidirectional oceanic acetone fluxes, which is coupled to a data‐oriented machine‐learning approach. The machine‐learning algorithm is trained using a global suite of seawater acetone measurements. GEOS‐Chem uses a fixed surface seawater concentration of acetone to calculate the oceanic fluxes. Both …

Phosphorus Variability In The Area Of Influence Of The Mid-Barataria Sediment Diversion, Peter Mates

LSU Master's Theses

Man-made levees along the lower Mississippi River prevent delivery of sediment from building and maintaining Louisiana’s coastal wetlands. The Mid-Barataria sediment diversions is designed to reintroduce Mississippi River water, sediment, and nutrients into the sediment-starved Barataria Basin. Phosphorus (P) is an important macronutrient for regulating primary production in coastal marine ecosystems. Wetlands can serve as a sink or source for phosphorus to the overlying water column through various retention and release processes, dependent on concentration. Louisiana coastal systems can be phosphorus limited due to much higher concentrations of bioavailable Nitrogen in river water. The high soluble molar N:P ( >50:1) …

The Medium-Term And Event-Scale Tropical Cyclone-Driven Morphodynamics Of A Vulnerable Barrier System With Emphasis On The Role Of Backbarrier Wetlands, Cody Lee Johnson I

LSU Doctoral Dissertations

Coastal mainland barriers and barrier islands provide the first line of defense against oceanic and meteorological forces. Coastal morphological change, which may degrade these barrier's defensive capabilities, occurs over a range of time scales, from geological epochs (>1000 years) to hours and seconds. Coastal morphological change at a vulnerable, but economically strategic, barrier system---the Caminada-Moreau Headlands, Louisiana---is investigated in terms of tropical cyclone impacts and their effects over a 15 year LIDAR survey time series. Analysis of the barrier's three-dimensional morphodynamics at medium-term (decadal) time scales reveals that, while subaerial volume was approximately conserved through time, the impact of …

Reproductive Effort Of Montastraea Cavernosa Across Depth In The Context Of Both Climate Change Refugia And Emergent Disease, Jeanne Bloomberg

LSU Master's Theses

As coral populations on shallow reefs decline globally, mesophotic coral ecosystems (MCE) have been suggested as potential coral refugia in the face of climate changes, leading to the development of a comprehensive deep reef refugia hypothesis. The current study assesses the climate and disease refuge potential of MCEs in the U.S. Virgin Islands (USVI) for the gonochoric, broadcast-spawning species Montastraea cavernosa. Polyp, population, and total habitat fecundities were estimated across the species’ depth range, and changes to population oocyte production over time due to recent ecosystem disturbances were considered. The number of gonads producing oocytes in each polyp and oocyte …

Identification And Quantification Of Microplastic Pollution In Water Samples And Four Species Of Fish From The Mississippi River, Kerrin E. Toner

LSU Master's Theses

Microplastics (£5 mm) have become a persistent anthropogenic pollutant and a growing environmental concern with evidence of them being found throughout several ecosystems. In recent years, there has been a growing recognition that rivers play a major role in transporting plastics from the land to the sea. The Mississippi River is the largest river in North America, draining land populated by over 100 million people. With high numbers of microplastics found in the waters of the northern of the Gulf of Mexico, it is likely that the Mississippi River is the primary source of these plastics. This study quantifies and …

Studies Of Quaternary Depositional Systems Of The Coastal Plain And Inner Continental Shelf Along The Georgia Bight: South Carolina And Georgia, U.S.A., Joshua H. Long

Electronic Theses and Dissertations

The Quaternary stratigraphy of the continental shelf offshore of South Carolina consists of stratigraphic units deposited in coastal plain, shallow marine, and shelfal environments bound by composite erosional surfaces that developed in response to numerous glacioeustatic cycles and overprinted by regional uplift. These units are commonly distributed laterally rather than stacked vertically, a function of the long-term, low shelf gradient and the resulting lack of accommodation. This study integrates high-resolution geological and geophysical data sets acquired offshore and onshore with existing data onshore into a comprehensive conceptual model describing the Quaternary geologic evolution of the coastal plain and continental shelf …

Long-Term Ndvi And Recent Vegetation Cover Profiles Of Major Offshore Island Nesting Sites Of Sea Turtles In Saudi Waters Of The Northern Arabian Gulf, Rommel H. Maneja, Jeffrey D. Miller, Wenzhao Li, Hesham El-Askary, Ace Vincent B. Flandez, Joshua J. Dagoy, Joselito Francis A. Alcaria, Abdullajid U. Basali, Khaled A. Al-Abdulkader, Ronald A. Loughland, Mohamed A. Qurban

Mathematics, Physics, and Computer Science Faculty Articles and Research

Vegetation is an important ecological component of offshore islands in the Arabian Gulf (AG), which maintains long-term resilience of these islands. This is achieved by influencing sediment retention and moisture acquisition via condensation during periods of high humidity and by providing a variety of microhabitats for island fauna. The resilience of offshore islands’ ecosystems in the Saudi waters is important because they host the largest number of nesting hawksbill and green turtles in the AG. This study defines the characteristics and the long-term trends in vegetation cover of the offshore islands used by sea turtles as nesting grounds in the …

Seasonal Transport Of Dissolved Inorganic Carbon And Total Alkalinity Across The Louisiana Shelf, Michelle M. Anderson

LSU Master's Theses

Rivers and wetlands are a major source of terrestrial derived carbon for coastal ocean margins. Unfortunately, Louisiana’s wetlands are threatened by ongoing high rates of erosion, deterioration, and unprecedented rates of river water discharge that changes seasonally, leading to a net loss of terrestrial carbon into the northern Gulf of Mexico (nGOM). There exists a current lack of understanding about the distribution of dissolved inorganic carbon (DIC) and total alkalinity (TAlk) within the shallowest regions of the Louisiana shelf. Even less is known about how the transport of DIC alters seasonally with changes in river outflow and shelf currents. Quantifying …

Microplastics In Mississippi River Fishes: A Watershed Approach, Ahmed Gad

LSU Master's Theses

Microplastics are plastic particles less than 5mm that come from different sources, such as industrial products, cosmetics, and the breakdown of the macroplastics. Microplastics derive from terrestrial sources but concentrate in flowing freshwaters where they may enter aquatic food webs. The northern Gulf of Mexico has shown very high microplastic concentrations, which are assumed to be sourced from the Mississippi River and its watershed. This study seeks to study microplastics in fish in the Mississippi River and the Gulf of Mexico. Fish stomachs and intestines from fish underwent chemical digestion, filtration, and microplastics identification and enumeration through FT-IR spectrometry. Chapter …

Author Correction: Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf

School of Earth & Environment Departmental Research

Correction to: NPJ Climate and Atmospheric Science https://doi.org/10.1038/s41612-020-0121-5, published online 08 May 2020

Sediment Transport And Geomorphological Evolution In The Transgressive Ship Shoal, Louisiana: Insights From Geophysical Observation, Modeling, And Machine Learning Studies, Haoran Liu

LSU Doctoral Dissertations

Ship Shoal has been a high-priority target sand resource for dredging activities to restore the eroding barrier islands in Louisiana, USA. Many studies have been performed in Ship Shoal in recent decades, but our knowledge of temporal and spatial variations of sediment transport and post-dredge morphology is still limited. The objectives of this dissertation are to explore the sediment infilling process, the spatial and temporal evolution of the morphology of dredge pits near and on Ship Shoal by using multiple methods. Scientific methods used in this study include (a) geophysical observation using bathymetry, side-scan and subbottom technique, (b) sediment transport …

Temperature And Salinity Distributions And Flushing Time Estimates In A Low-Inflow California Estuary, Sydney N. Wewerka

Physics

This study examines the temperature and salinity distributions in Morro Bay, a small, seasonally LIE located on the central coast of California. In Morro Bay, eelgrass (Zostera marina; a temperate seagrass), like all seagrasses, is a critical habitat-forming species that supports a large variety of invertebrate, fish, and bird species in the estuary (MBNEP, 2018). Since 2007, eelgrass in the estuary has declined by over 90%, with most losses occurring in the back regions (i.e., head) of the estuary (MBNEP, 2018). Near the mouth, eelgrass meadows have remained resilient, indicating that gradients in environmental conditions throughout the bay may be …

Benthic Nitrogen Dynamics In Response To Deltaic Succession, Anthropogenic Fertilization And Hurricane Events In An Emerging Coastal Deltaic Floodplain Within The Mississippi River Delta Plain, Song Li

LSU Doctoral Dissertations

Increasing concentrations of nitrogenous fertilizer (NO₃^-) in rivers have potentially altered benthic nitrogen (N) cycling in coastal deltaic floodplains at the continental margins of major rivers. Here I evaluated the N removal capacity of a newly emergent coastal deltaic floodplain [Wax Lake Delta (WLD)] within the Mississippi River Delta Plain using continuous flow-through incubations. I investigated the response of benthic N dynamics in WLD to deltaic succession, anthropogenic fertilization and hurricane events. The estimated annual NO₃^- removal of 896 Mg N yr^-1 in WLD accounts for 10 to 27% of total NO₃^{- …}

Synergistic Use Of Remote Sensing And Modeling For Estimating Net Primary Productivity In The Red Sea With Vgpm, Eppley-Vgpm, And Cbpm Models Intercomparison, Wenzhao Li, Surya Prakash Tiwari, Hesham El-Askary, Mohamed Ali Qurban, Vassilis Amiridis, K. P. Manikandan, Michael J. Garay, Olga V. Kalashnikova, Thomas C. Piechota, Daniele C. Struppa

Mathematics, Physics, and Computer Science Faculty Articles and Research

Primary productivity (PP) has been recently investigated using remote sensing-based models over quite limited geographical areas of the Red Sea. This work sheds light on how phytoplankton and primary production would react to the effects of global warming in the extreme environment of the Red Sea and, hence, illuminates how similar regions may behave in the context of climate variability. study focuses on using satellite observations to conduct an intercomparison of three net primary production (NPP) models--the vertically generalized production model (VGPM), the Eppley-VGPM, and the carbon-based production model (CbPM)--produced over the Red Sea domain for the 1998-2018 time period. …

Law School News: Dennis W. Nixon: Doctor Of Laws, Honoris Causa 05-09-2020, Roger Williams University School Of Law

Life of the Law School (1993- )

No abstract provided.

Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf

School of Earth & Environment Departmental Research

Sea-level rise projections and knowledge of their uncertainties are vital to make informed mitigation and adaptation decisions. To elicit projections from members of the scientific community regarding future global mean sea-level (GMSL) rise, we repeated a survey originally conducted five years ago. Under Representative Concentration Pathway (RCP) 2.6, 106 experts projected a likely (central 66% probability) GMSL rise of 0.30–0.65 m by 2100, and 0.54–2.15 m by 2300, relative to 1986–2005. Under RCP 8.5, the same experts projected a likely GMSL rise of 0.63–1.32 m by 2100, and 1.67–5.61 m by 2300. Expert projections for 2100 are similar to those …

Refining Interpretations Of A Deglacial Record In Gulf Of Mexico Marine Sediment Cores Using Foraminifera C-14 Dates And Multi-Proxy Sediment Analyses, Lindsey R. Monito

Senior Honors Projects, 2020-current

The upper fourteen sections of three cores recovered from the International Marine Past Global Changes Study (IMAGES) VIII/Paleoceanography of the Atlantic and Geochemistry (PAGE) 127 expedition of 2002, are stratigraphic records of the climate and provenance variations that influenced sediment deposition in the Gulf of Mexico during the Pleistocene and Holocene. Though originally cored by the USGS for gas hydrate investigations, cores MD02-2535, MD02-2555, and MD02-2560 have been repurposed for undergraduate course-based paleoclimate research at JMU. Shipboard interpretations of the color reflectance data for these cores suggested that two dark stratigraphic intervals present in all of the cores were regional …

Microplastic Prevalence In Four Oregon Rivers Along A Rural To Urban Gradient Applying A Cost-Effective Validation Technique, Amy Valine, Ashley Peterson, Dorothy Horn, Kaegan M. Scully‐Engelmeyer, Elise F. Granek

Environmental Science and Management Faculty Publications and Presentations

Microplastics are ubiquitous in our environment and are found in rivers, streams, oceans, and even tap water. Riverine microplastics are relatively understudied compared to those in marine ecosystems. In Oregon, we sampled eight sites along four freshwater rivers spanning rural to urban areas to quantify microplastics. Plankton tow samples from sites along the Columbia, Willamette, Deschutes, and Rogue Rivers were analyzed using traditional light microscopy for initial microplastic counts. Application of Nile Red dye to validate microplastics improved microplastic identification, particularly for particles (Wilcox Test; p‐value=0.001). Nile Red‐corrected microfiber abundance was correlated with human population within five kilometers of the …

Geochemical Tracers Of Arctic Ocean Processes: A Study Of Gallium, Barium, And Vanadium, Laura M. Whitmore

Dissertations

The Arctic Ocean is linked to the global oceans and climate through its connectivity with the North Atlantic Ocean and the regional thermohaline deep water formation sites. It’s also a region undergoing rapid environmental change. To inform the community of potential changes in geochemical and biogeochemical cycles, this dissertation addresses three dissolved geochemical tracers (gallium, barium, and vanadium) as indicators of Arctic Ocean processes. Gallium is tested as a replacement for nutrient-type tracers in an effort to deconvolve Pacific and Atlantic derived waters in the Arctic Ocean basins. These water masses carry different heat and salt content and can influence …

The Effect Of Radium Partitioning On Hydrothermal Fluid Flow Determination Across Guaymas Basin, Charlotte R. Kollman

Electronic Theses and Dissertations

Analysis of the distribution of radium through sedimentary porewater profiles is a promising method for constraining diffuse discharge/recharge flow rates in hydrothermal settings; these parameters are critical for evaluating hydrothermal circulation and its chemical and biological implications. The short-lived 224Ra (T1/2 = 3.54 days) is an effective tracer due to its behavior in marine environments and changes in activity due to ingrowth/decay. However, the distribution of radium may be influenced by its varying solid:aqueous partitioning coefficients (Kd) and is critical to understand for any study utilizing radium as a tracer. This project explores Kd across the hydrothermally active Guaymas Basin …