Oceanography Commons^™

Understanding Biogeochemical And Physical Controls On Methane Air-Sea Exchange Fluxes In The Pacific Ocean, Sarah Raney

Master's Theses

Methane and trace element samples were collected on GEOTRACES GP15 Pacific Meridional Transect (PMT) cruise conducted between the Aleutian Islands (57 °N) and Tahiti (20 °S) from September to November 2018. Uncertainty in methane air-sea exchange fluxes was determined using a propagation of errors approach. Fluxes ranged from -0.88 to 4.9 µmol CH₄ m^-2 d^-1. Average CH₄ flux along the Alaskan margin was 2.2 ± 2.9 µmol CH₄ m^-2 d^-1. Methane fluxes decreased moving southward and increased to their open ocean maximum around 20 °N before declining in equatorial waters. Near …

A Step Toward Reconstructing Climate Variability Druing The Last Ice Age Cycle In The Northeast Pacific Region, Blaine Lynch-Gadaleta

Senior Honors Projects

This study is designed as a step toward reconstructing the climate variability in the Northeast Pacific during the last ice age cycle, including the glacial and deglacial transitions. Reconstruction may also contribute to the regional picture of climate change and potentially provide new insights into the pattern of variability in the Northeast Pacific. Deep-sea sediment core AT26-19 09PC was collected west of the Juan de Fuca Ridge in the Northeast Pacific Ocean. Samples were analyzed in 1 cm intervals, representing approximately 300-year resolution. The abundance of mineral grains, planktonic foraminifera, and the polar foraminifera N.pachyderma was quantified using split aliquots …

Using Stock And Flow Modeling To Address Knowledge Gaps In Marine Plastic Pollution Data, Daniel P. Martin

OES Theses and Dissertations

As plastic becomes a ubiquitous part of society, its growth outpaces waste disposal infrastructure and enters the environment as physical and chemical pollution. Plastic can also erode during the use cycle and reach the environment without any chance of being arrested by collection efforts. Plastic is a hazard to many parts of the earth’s life support system but there are many knowledge gaps regarding the processes by which plastic moves through the use cycle and environment. In particular, the ocean is generally regarded as a sink for plastic out of which it is difficult to escape, but plastic can sink …

Understanding The Public Perception Of Available Scientific Resources In Coastal Southern Maine, James Gallagher

Senior Honors Projects

I have focused my education as an undergrad towards the effective communication of scientific fact to non-scientific groups. This area of study has recently been dubbed Science Communication and it encompasses the effective articulation, communication, and education of scientific topics to people who haven’t dedicated their lives to scientific study. A major component of effective Scientific Communication is understanding your audience and what kind of communication strategies are best for a chosen demographic.

I grew up in Ocean Park Maine, a small town on the coast of Southern Maine which drove my interest in Marine Science. With my experience in …

Testing The Efficacy Of Uvc Leds For Biofouling Control, Margaret Jeannette Giggie

Theses and Dissertations

The use of ultraviolet-C (UVC) light as a biofouling preventative has been successfully demonstrated using mercury-based lamps. However, these lamps have several limitations (such as fragility and use of mercury), and the use of UVC LEDs (light-emitting diodes) has been suggested as an alternative. Several experiments were conducted to assess the efficacy of LED strips (29 W, 270 nm, emittance angle of 130º) for biofouling control, as well as to compare them to a classic lamp (25 W, 254 nm, emits UVC light at 360º). Experiment #1 assessed the biofouling abundance and community composition on test panels exposed to either …

Climate-Driven Stock Shifts And Expansions In The U.S. Northeast Shelf: Identifying Challenges, Opportunities, And Barriers Through Fishermen And Manager Perspectives, Sophie A. Swetz

All Theses And Dissertations

Climate-driven warming in the U.S. Northeast Shelf (NES) has led to changes in the spatial distributions of many marine resources. Shifts and expansions of commercially important fish stocks pose major challenges to fishermen and fisheries managers in this region. American lobster (Homarus americanus) in the Gulf of Maine (GOM) is one of these impacted stocks and is projected to continue its shift towards more northern and offshore areas. Continued ocean warming could potentially reduce the GOM lobster stock by up to 60% over the next several decades. Given Maine’s reliance on its lobster fishery—which contributes over 80% of …

Coastal Sediment Response To The Diel Oxygen Cycle, Kara Gadeken

Graduate Theses and Dissertations (2019 - present)

Shallow coastal sediments are sites of intense respiration and organic matter breakdown. Macroinfauna bioturbate and bioirrigate sediments which supplies microbes with oxygen and newly deposited organic material from surface sediments, facilitating microbial remineralization of organic matter. These processes depend heavily on the concentration of dissolved oxygen in overlying water. Shallow water oxygen patterns often follow a diel cycle as dissolved oxygen decreases at night due to respiration and then increases during the day with photosynthesis, creating recurring suboxic conditions that are potentially stressful to organisms. Sediment oxygen flux is known to depend on ambient dissolved oxygen concentration, but behavioral responses …

Near-Inertial Wave Energetics Modulated By Background Flows In A Global Model Simulation, Keshav J. Raja, Maarten J. Buijsman, Jay F. Shriver, Brian K. Arbic, Oladeji Siyanbola

Faculty Publications

We study the generation, propagation, and dissipation of wind-generated near-inertial waves (NIWs) in a global 1/25° Hybrid Coordinate Ocean Model (HYCOM) simulation with realistic atmospheric forcing and background circulation during 30 days in May–June 2019. The time-mean near-inertial wind power input and depth-integrated energy balance terms are computed for the total fields and the fields decomposed into vertical modes to differentiate between the radiative and (locally) dissipative components of NIW energy. Only 30.3% of the near-inertial wind input projects onto the first five modes, whereas the sum of the NIW energy in the first five modes adds up to 58% …

Exploring Indicator Displacement Assays For Phosphate Detection In Seawater, Francis Radics

Chemistry & Biochemistry Student Scholarship

Francis Radics ’22
Major: Biochemistry
Faculty Mentor: Dr. John Breen, Chemistry and Biochemistry

Indicator displacement assays are based on the optical signal modulation of a noncovalently bound indicator upon dissociation by an analyte species. Our work has focused on exploring the lower detection limits for luminescent displacement assays for inorganic phosphate in seawater using complex ions containing two di(2-picolyl)amine ligands (also called DPA or bis(2-pyridylmethyl)amine), each coordinating a zinc cation. Following the work of B.D. Smith and coworkers, we have prepared three ligands by covalently attaching two DPA moieties, 2,6-bis(chloromethyl) benzene, and 2,6-bis(chloromethyl)-4-methylphenol, and 1,2-phenylenedimethylamine, for assays with 6,7-dihydroxy-4-methanesulfonic acid …

Sedimentation Processes In A Dredge Pit And Surrounding Environment In Northern Gulf Of Mexico, Adam M. Gartelman

LSU Master's Theses

Louisiana’s Coastal Protection and Restoration Authority has been using dredged sand from onshore and offshore sites for barrier island restoration and beach nourishment projects. Caminada dredge pit (CDP) located on eastern Ship Shoal in inner Louisiana shelf underwent two increments in 2014 and 2016, with material used to restore Caminada Headland and nearby areas. Multiple pits in East Terrebonne borrow areas (ET) right next to CDP were then used for East Timbalier Island and other barrier islands near Terrebonne Bay. ET1, north of CDP, was dredged in 2020, and ET2, west of CDP, was dredged in 2020 and 2021 used …

Controls On Buffering And Coastal Acidification In A Temperate Estuary, Christopher W. Hunt, Joseph Salisbury, Douglas Vandemark

Faculty Publications

Estuaries may be uniquely susceptible to the combined acidification pressures of atmospherically driven ocean acidification (OA), biologically driven CO2 inputs from the estuary itself, and terrestrially derived freshwater inputs. This study utilized continuous measurements of total alkalinity (TA) and the partial pressure of carbon dioxide (pCO2) from the mouth of Great Bay, a temperate northeastern U.S. estuary, to examine the potential influences of endmember mixing and biogeochemical transformation upon estuary buffering capacity (β–H). Observations were collected hourly over 28 months representing all seasons between May 2016 and December 2019. Results indicated that endmember mixing explained most of the observed variability …

Investigating Temporal Groundwater Interactions Between A Barrier Island And High Marsh Environment, Dean Wrobel

Undergraduate Research Competition

Saltmarsh hydrogeology can be characterized as exceptionally dynamic, with a diversity of pore water salinities, sediment porosities, and varied hydrologic inputs and outputs such as groundwater, precipitation, and tidal cycles. Of the studies done in these systems, much attention has been focused on the low marsh with regard to tidal pumping and the consequent horizontal pressure gradients which affect the subsurface hydraulic head. Perhaps, an equally dynamic boundary is expected at the groundwater interface of the barrier island and high marsh. Here, electrical resistivity tomograms were generated in a back-barrier, high-marsh site landward of Waties Island, South Carolina. Co-located transects …

Microplastic Concentration Analysis Of The Atlantic Sand Fiddler Crab (Leptuca Pugilator) In Murrells Inlet, South Carolina, Caroline Conner

Undergraduate Research Competition

Microplastics pose a great threat to the natural environment, a threat not aided by their increasing abundance in marine waters. To assess how this is affecting our local area, I examined the microplastic concentration in fiddler crabs, a keystone species in intertidal zones, from two marsh systems in Murrells Inlet. The quantity, color, and type of microplastic found were recorded from each of the 120 crabs sampled. This information is revelant not only in monitoring the health of a species that plays a major role in nutrient recycling and prevention of anoxic conditions, but also as a caution to us. …

What Lives On Offshore Artificial Reefs In South Carolina? An Analysis Of Epifaunal Reef Communities And How They Vary With Reef Age, Sydney Madden

Undergraduate Research Competition

Artificial reef structures have been deployed across the coast of South Carolina in an effort to increase fish habitat and provide other ecosystem services. There are approximately 45 artificial reef systems established by the South Carolina Department of Natural Resources (SCDNR) over several decades. The hard structure—frequently composed of concrete, old boats, or other structures—forms unique high relief hard-bottom habitat in the otherwise largely low relief coastal shelf. Currently, there is little published on the species composition of the epifaunal communities in this region, how much biomass they support, and how they develop over time. We studied two established artificial …

A Numerical Investigation Of Flood And Sediment Dynamics Over The Coastal Watersheds During Hurricane Events, Dongxiao Yin

LSU Doctoral Dissertations

Landfalling tropical cyclones can cause catastrophic floods and sediment disturbance over the coastal watersheds. This study aims to unravel the contribution of different processes to hurricane-induced flooding, to assess the uncertainties in flood modelling and forecasting, and to advance the techniques in sediment simulation over coastal watersheds during hurricanes.

First, I examined the hydrometeorology and hydrology of Hurricane Florence (2018) induced inland flooding. My results suggest that the slow motion in combination with the “L-shaped” path was the most distinctive feature of the hurricane that incurred catastrophic and widespread rainfall and flooding over the Cape Fear River Basin (CFRB).

Second, …

Effects Of Meteorologic Events On Wave Climate And Current Regime In A Shallow, Microtidal Bay, Jay S. Merrill

LSU Master's Theses

Along coastal Louisiana and within the shallow microtidal Barataria Bay estuary, meteorological events can play a primary role in influencing wave climate and circulation patterns. Understanding the effects of hurricanes and smaller tropical storms on hydrodynamic processes is important for constraining and predicting hydrodynamic variation in Barataria Bay, which, largely due to impacts from wave energy, is currently experiencing rapid wetland loss and is a major focus of coastal restoration efforts. Two bottom-mounted upward-facing Acoustic Current Doppler Profilers and wave, temperature, and depth recorders were installed in the lower portions of Barataria Bay to measure the wave climate and three-dimensional …

Circulation, Volume 27, No. 2, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Spring 2022 issue of CCPO Circulation featuring the article "Looking Back While Moving Forward," by Sönke Dangendorf.

The Battle For The Sea: Tourism Development And Public Ocean Access In Jambiani, Zanzibar, Sophie Beauchesne

Independent Study Project (ISP) Collection

The battle for coastal access is a prevalent and controversial issue in both the Global North and the Global South (Mongeau, 2001; Ojo, 2013). Due to investment in coastal land, vulnerable communities around the world are losing their access to the sea (Ojo, 2013; Bennett, Govan & Satterfield, 2015). Battles for ocean access in the Global North tend to focus on recreational activities, but what is to be said about ocean access in the Global South, where access to the sea is needed for the survival of entire communities? (Mongeau, 2001;). Using geographical mapping, environmental condition assessments and open-ended interviews …

Assessing The Threat Of Coral Decline On Fish Diversity In Response To Temperature, Ryland Talmadge

Independent Study Project (ISP) Collection

Misali, a PECCA-protected island off the east coast of Pemba, Tanzania, is considered to be a marine biodiversity hotspot with a protected Non-Extractive Zone (NEZ) and remaining Extractive Zone (EZ). Upon protection, the island’s fringe reefs faced severe coral bleaching during the 1998 bleaching event, estimated to kill up to 70% of corals. Since the event, several others have occurred in addition to restructuring the management plan in 2006 to expand the region to 1000km. While the damage from the most recent coral bleaching event in 2020 has yet to be surveyed, this study investigates the current reef health in …

The Relationship Between Substrate Composition, Community Structure And Feeding Preferences Of Parrot Fishes (Scaridae) In Anmardub, Guna Yala Coastal Reefs, Caitlin Amman

Independent Study Project (ISP) Collection

Coral reefs are important marine ecosystems, as they support biodiversity and generate buffer zones, yet their abundance is incredibly limited globally. One of the main threats that coral reefs face is excessive macroalgal coverage, which limits sunlight from reaching corals, and thus, limits the energy that can reach them. Parrot fish (Scaridae) are keystone herbivores, as they consume macroalgae growing on corals, which aids in reef survivability. While there is previous research on the abundances, sizes, and feeding habits of Scaridae species in the Caribbean, there is no published research on how community structure and feeding preferences of parrot fishes …