Oceanography Commons^™

Microplastics In St. John, United States Virgin Islands Sediments: Methodological Approaches And Variability Of Microplastics Concentrations And Accumulation Rates, Henry B. Arbaugh, Sarah C. Gray, Dimitri Deheyn

Theses

Sediment samples were collected from a near shore and reef site in Coral Bay, St. John, United States Virgin Islands (USVI) from 2007-2016, using tube sediment traps. These samples provide an opportunity to study microplastics (MPs) in an area where no previous MP studies have been performed. Most sedimentary MP studies utilize benthic samples which can only measure MP concentrations (#MP/g or #MP/mL sediment), while sediment traps can provide MP accumulation rates (#MP/cm²/day) as a function of time. However, the methods used for extracting MPs from benthic samples have not been tested using sediment trap samples whose characteristics, …

Efficient Preservation Of Old Methane-Derived Organic Carbon In Deep-Sea Surface Sediments, Rui Bao, Yangli Che, Mingzhi Liu, Naiyu Zhang, Yang Zhou, Lihua Dong, Shen Li, Owen A. Sherwood, Min Yu, Zongheng Chen, Shengxiong Yang, Nan Wang, Longhai Zhu, Jiawang Chen, Mutai Bao, Haoshuai Li, Luonan Chen, Weifeng Wu, Haiyue Ma, David J. Burdige

OES Faculty Publications

Methane released from the subseafloor is significantly attenuated during upward migration, yet the preservation of methane-derived organic carbon (OC) in global deep-sea sediments remains poorly understood. Here, we measured carbon isotopes coupled with temperature-ramped analyses on various methane seepage sediments. Our results reveal a correlation between the radiocarbon (¹⁴)C) content in deep-sea surface sediments and sulfate-methane transition depth. Notably, our findings suggest that a substantial amount of (¹⁴)C-depleted OC may originate from deep-seated methane and is efficiently preserved in surface seepage sediments. We propose that the efficient OC preservation is related to microbial-mediated aggregate formation at the seawater-sediment interface, where …

Testing The Limits Of Provenance Analysis From Basaltic Fluvial Sediment Near Sandvatn, Iceland, As A Mars Analog, Audrey R. Putnam, Kirsten L. Siebach, Michael T. Thorpe, Valerie M. Tu, Elizabeth B. Rampe, Candice C. Bedford, Gelu Costin, Joseph J. Tamborski

OES Faculty Publications

Detrital sediments that accumulate downstream and are preserved in sedimentary rocks can allow characterization of geologic formations that are inaccessible for spatial or temporal reasons. However, mixing, sorting, and alteration of sediment during transport may complicate reconstruction of protolith characteristics. We test the preservation of three key provenance signals in coarse fluvial sand at a Mars analog watershed in Iceland to determine whether detrital sediments capture (a) watershed magmatic chemical variation, (b) textural indicators of lava-water interaction during eruption and cooling, and (c) hydrothermal alteration. Specifically, we tested whether diagnostic variations in rock mineralogy, chemistry, and texture can be recovered …

Differential Growth Dynamics Of Common Salt Marsh Species Spartina Alterniflora And Juncus Roemerianus Under Varied Sediment Amendments, Caitlin Hemphill, Richard P. Hale, Erik S. Yando

Biological Sciences Faculty Publications

Introduction

Many coastal wetlands are at high risk of degradation or loss due to sea‐level rise. Restoration techniques for maintaining coastal marshes are paramount, with thin‐layer placement (TLP) emerging as one feasible solution. Despite TLP's utilization, additional research is needed on species‐ and sediment‐specific responses.

Objectives

Our research combines greenhouse and field experimentation to test species and sediment composition responses aimed at maximizing vegetation while maintaining increased elevation.

Methods

The greenhouse experiment used two common marsh plants, Spartina alterniflora and Juncus roemarianus. Five centimeters of sediment (mud, sand, and sand/mud mix) was added, and subsequent sediment and vegetation metrics …

A Sedimentary Source Of Rare Earth Elements In The North Atlantic, Rylee D. Lindner

Electronic Theses and Dissertations

Individually and as a series, the Rare Earth Elements (REEs) are powerful geochemical tracers of environmental processes. However, ambiguities in the oceanic budgets of the REEs hamper their application. Growing evidence suggests a sedimentary benthic flux via the pore water is the major source of REEs to the ocean, with extrapolated estimates of this flux being equivalent in magnitude to that “missing” from modern budgets. However, existing pore water REE data are available from only a few locations globally with no representative dataset from the open North Atlantic. This data scarcity limits our ability to constrain flux estimates and understand …

Floodplain Lake Hydrodynamic And Morphodynamic Connections Through Hydraulic Modeling Along The Pee Dee River, Sc, Charles Cj Mina

Electronic Theses and Dissertations

Rivers have been essential in the success of humankind. This reliance has created a vested interest in studying the rivers' environmental history through using floodplain deposits, with the assumption that coarser sediments correlate to higher discharge floods. However, shifting hydrological connectivity and hydrodynamics can complicate this correlation in primary repositories of flood deposits, oxbow lakes, by altering the texture of sediments delivered to them. Studying these complications is essential for quantifying paleoflood magnitude using the sediment record, but has been difficult, as the currently used index of hydrological connectivity relies on water stage, which does not reflect the sediment flux …

An Investigation Of Paleoclimate Through A Sedimentological Lens In The Gulf Of Mexico And Western North Pacific, Sarah Monica

Dissertations

This dissertation explores the use of sediment cores as proxy data for the reconstruction of paleoclimatic and environmental conditions. Human-caused climate change is leading to dramatic shifts in the global climate. As the instrumental record of climate is relatively short compared to the amount of time Earth has experienced weather, this work aims to extend our knowledge of climate beyond the instrumental record, thereby improving our holistic understanding of the climate system. In Chapter one, sediment cores from the central Texas inner shelf are used to produce a record of intense tropical cyclone (TC) activity over a ~4500-year period. X-Ray …

The Petm: A Window Into Earth's Future Climate, Jacalyn M. Wittmer Malinowski

Climate Change and the Individual, 2025-26

The Paleocene-Eocene Thermal Maximum (PETM) is not just an event that occurred in Earth’s distant past (~55 million years ago) but is a crucial lesson for today’s meteoric climate change. The PETM offers a historical parallel of rapid flux of greenhouse gases into the atmosphere that caused global warming, ocean acidification, dramatic changes in weather, and extinctions. This global warming event was the result of 20,000 years of “rapid” warming (in geological terms) however, we are experiencing rates of warming that are 5-10x higher than PETM levels. We are not experiencing rapid warming today, in comparison to the past, we …

08 - Blue Carbon Sequestration And Sediment Storage In Seagrass Meadows Of South Bay, Luke C. Clements, Adriana Amrhein, Richard P. Hale

Undergraduate Research Symposium

Blue carbon is stored in coastal and marine ecosystems like seagrass meadows and salt marshes, which helps combat climate change by preventing greenhouse gas emissions. This study examines the role of seagrass in carbon storage by comparing sediment cores from a mud channel and a seagrass meadow in South Bay.

We collected a 100 cm core from the mud channel and a 55 cm core from the seagrass area, taking samples every 10 cm to analyze grain size and organic carbon content. Using a wet sieving method, we separated sand from mud and measured organic carbon through loss on ignition. …

Successful Eastern Oyster (Crassostrea Virginica) Recruitment On Intertidal Artificial Substrates In Virginia, Usa, Rochelle D. Seitz, Kathleen E. Knick, Emily Suchonic, Amanda Pysher

OES Faculty Publications

Declines of eastern oyster (Crassostrea virginica) populations and scarcity of natural oyster shell necessitate quantifying the effectiveness of artificial oyster reef substrates over varying environmental conditions. Oyster castles are often used in intertidal areas with moderate wave energy; however, new concrete, natural-looking substrates, GROW Reef Tiles, are now available. Eastern oyster recruitment and size on oyster castles (OC) and GROW Reef Tiles (GT), with 27% higher surface area on OC, were assessed three times over 25 months in locations with varying salinity. Four sites in the Chesapeake Bay region were examined: Cherrystone Inlet, Mockhorn Bay, Elizabeth River, and …

Core-Top Constraints On The Ecology And Paleothermometry Of Planktic Foraminifera In The Indian Ocean, Ryan H. Glaubke, Elisabeth L. Sikes, Natalie E. Umling, Katherine A. Allen, Matthew W. Schmidt

OES Faculty Publications

The magnesium-to‑calcium ratio (Mg/Ca) of fossil foraminifera is a widely used geochemical proxy for reconstructing past ocean temperatures. Culturing experiments have shown that, for some species, nonthermal influences like salinity and carbonate chemistry play a non-trivial role in the incorporation of Mg into foraminiferal calcite. Inclusion of these variables into Mg/Ca calibrations have provided a better fit to core top and sediment trap data in some recent studies, but the widespread covariation of potential control variables in the open ocean and the lack of multivariate calibrations for some species warrants additional work. Here, we assess Mg/Ca calibrations for four common …

Moderate Heating Renders 7.8-Million-Year-Old Sedimentary Organic Matter Bioavailable, Shuchai Gan, Verena B. Heuer, Frauke Schmidt, Lars Wormer, Faming Wang, Rishi R. Adhikari, Patrick Hatcher, Ann Pearson, Kai-Uwe Hinrichs

Chemistry & Biochemistry Faculty Publications

Marine sediments are a large reservoir of recalcitrant organic matter and host microbes at subsurface depths exceeding 2.4 kilometers and temperatures up to 120°C, yet the mechanisms supplying bioavailable substrates remain unclear. Here, we investigated 7.8-million-year-old sediment from IODP Site C0012 off the Nankai Trough, Japan, through incubations at 20°, 35°, 55°, and 85°C to simulate burial temperatures. Using 3D fluorescence spectroscopy and ultrahigh-resolution mass spectrometry, we tracked changes in dissolved organic matter (DOM). At 35°C, humic-like DOM was released alongside metal ions, exhibiting low bioavailability. At 55°C, abiotic decomposition of humic compounds generated smaller, more bioavailable DOM, promoting fermentation. …

Geomorphic Evolution Of St. Augustine Inlet, St. Johns County, Florida, Kristen Becker

Theses and Dissertations

Tidal inlets interrupt longshore sediment transport, influencing adjacent beach morphology and allowing the exchange of water and sediment between the open oceans and protected back barrier bay. Inlets evolve through a combination of natural processes and are highly dynamic zones where sediment exchanges cause shifting shoreline positions nearby and create new morphological features. Barrier islands/beaches that are close in proximity to inlets evolve and are an important natural feature that dissipates wave energy and protects inland areas. Both natural and anthropogenic processes that affect barrier islands will be investigated during this study, including storm activity, waves, wind, water level, and …

Sedimentary Characteristics Of Flood Deposits In Coastal And Fluvial Environments: Examples From Washover Fans (North Carolina, Usa) And Floodplain Deposits (Mississippi, Usa), Shara Gremillion

Dissertations

Extreme flooding from severe and prolonged meteorological events and / or overbanking rivers are some of the most deadly and expensive disasters globally, impacting millions of lives, the environment, and property. People living in vulnerable areas, such as near coasts and rivers, are the first to be impacted with effects of these flood hazards. Scientific studies and their results can aid communities and officials in planning and preparing for those flood impacts. In this three-part study, flood impacts from coastal storms in North Carolina, and flooding along the Mississippi River (MSR) in the state of Mississippi, USA are assessed from …

Coastal Sedimentary Records Of Extreme Events And Human Activity: Examples From Hurricanes And Microplastics, Nicholas T. Culligan

LSU Doctoral Dissertations

Coastal regions are uniquely vulnerable to a myriad of natural and anthropogenically caused stresses such as hurricane strikes and chronic microplastic pollution. Both hurricanes and microplastics have major negative effects on global coastlines and are forecast to become more damaging in the future. However, current model trends are based on limited modern data and may not provide an accurate or comprehensive view of the future. Therefore, this dissertation investigates coastal stratigraphic records to determine long-term past trends of these presses and pulses so that researchers, stakeholders, and policy makers can use them to enact strategies to mitigate damages from worsening …

Exploring Microplastic Concentrations And The Sedimentology Of San Diego's Offshore Benthic Environments, Rachel Sarner

Theses

Marine pollution studies are showing infiltration of plastic debris in remote parts of oceans including the deep sea. Microplastics (MPs) are being discovered not only in the ocean’s water column but also benthic sediments reaching thousands of meters in depth. This is the first study to analyze MP concentrations in conjunction with sedimentary characteristics from varying deep-sea environments (coastal, deep ocean, offshore terrace) in the Southern California Continental Borderland (CCB). Our goal for this study was to observe how the concentration and type (morphology, color, size) of microplastics varied with distance from shore, with water depth, and between different submarine …

Applied Depositional Geosystems Of The Coos Bay Basin, Oregon: Organic Geochemistry, Maturation, Paleoenvironmental Reconstruction And Biostratigraphy Of The Coaledo Delta During The Middle Eocene Climatic Optimum (Meco), Allison K. Barbato

LSU Doctoral Dissertations

The Coos Bay Basin on the southwestern coast of Oregon is a forearc basin that contains exceptionally preserved Eocene to Miocene, tidal to wave-dominated, shallow deltaic to deep marine sediments of the Coaledo Delta. Coastal depositional environments are known to host source, reservoir, and seal rocks. Climate, topographic relief, and geographical position all play an important role in regional vegetation development and oceanic setting. This study assesses 84 outcrop and 12 core samples from Coos Bay for their organic geochemical characteristics and microfossil assemblage to provide source rock characterization information, organofacies descriptions, environmental reconstructions, and age control.

Results indicate the …

Southern Maine, New Hampshire, And Northern Massachusetts Continental Shelf Geophysical Database: 2022 Field Campaign – Grain Size Data, Station Summaries, And Seafloor Photographs, Larry G. Ward, Rachel C. Morrison, Michael Bogonko

Data Catalog

Presented in this data report are the geophysical data collected during a major field campaign in 2022, with the purpose of obtaining ground truth for the expansion and improvement of high-resolution surficial geology maps of the western Gulf of Maine (WGOM) and for the description of reference sites developed for future evaluations of acoustic systems (Ward et al., 2021a; 2021b). Data from the UNH Ocean Engineering 972 Hydrographic Field Course classes in 2021 and 2022 are also included. This expansion of the geophysical database is being used to verify seafloor classifications in previously mapped areas that lack sufficient data, and …

Interactions Between Sediment Mechanical Structure And Infaunal Community Structure Following Physical Disturbance, William Cyrus Roger Clemo

Graduate Theses and Dissertations (2019 - present)

Shallow, river-influenced coastal sediments are important for global carbon storage and nutrient cycling and provide a habitat for diverse communities of invertebrates (infauna). Elevated bed shear stress from extreme storms can resuspend, transport, and deposit sediments, disrupting the cohesive structure of muds, and sorting and depositing sand eroded from beaches. These physical disruptions can also resuspend or smother infauna, decreasing abundances and changing community structure. Infaunal activities such as burrowing, tube construction, and feeding can impact sediment structure and stability. However, little is known about how physical disturbance impacts short and long-term sediment habitat suitability and whether disturbance-tolerant infauna influence …

The Tidal Prism, Viable Eelgrass Habitat, And The Effects Of Sea Level Rise In Morro Bay, Kaden A. Caliendo

Master's Theses

The tidal prism, or the volume of water exchanged from the sea to an estuary from mean low to mean high tide, influences system hydrodynamics and ecological functioning. Since 1884, the tidal prism in Morro Bay, California has been estimated to be decreasing over time due to sedimentation from upstream practices. What is the current tidal prism in Morro Bay and how will that change with sea level rise? How will eelgrass respond to rising sea levels?

For this study, inexpensive tidal gauges were deployed at four locations in Morro Bay from March to August 2023 to measure spatially varying …

History Of Ice-Rafting In The Arctic Ocean During Glacial Maxima Through Marine Isotope Stage 6, Shannon M. Cofield

OES Theses and Dissertations

Numerous studies attempted to reconstruct Arctic paleoclimate, specifically ice mass timing and locations, during glacial maxima. While some regions, like the Barents-Svalbard Ice Sheet (BSIS) are well-studied, they may benefit from a high-resolution paleo proxy. Other regions are highly contested, such as the East Siberian Sea or the presence of a central Arctic Ocean ice mass.

This research uses an Fe-grain provenance method to (1) define how the BSIS behaved during Marine Isotope Stage (MIS) 2, 4, and 6, and when it retreated; (2) determine the presence and ages of Shelf Ice Masses (SIMs) in the Beaufort Sea and East …

Hydrodynamic Characteristics And Sediment Distribution Patterns In Wulan Delta Estuary, Demak, Indonesia, Max Rudolf Muskananfola, Sigit Febrianto, Diah Ayuningrum

Makara Journal of Technology

The Wulan Delta, located in Wedung, Demak, was formed due to the sedimentation process of the Wulan and Serang rivers. Sediment transport starts from rivers to the sea; the process carries nutrients and various chemicals derived from agricultural, industrial, or household activities. This study aims to analyze the characteristics of hydrodynamics, suspended sediment, and bottom sediments in the Wulan Delta waters, Demak. Field data were collected in transitional season two (October) 2022. The obtained data were then analyzed in the laboratory at the Faculty of Fisheries and Marine Science. Results showed that the speed of the surface current in the …

Coastal Morphology And Sediment Deposition On Adjacent Coral Reefs At Misali Island, Sophia Rosati

Independent Study Project (ISP) Collection

Terrestrial and marine ecosystems are frequently interpreted under separate lenses. On a 1 km wide island, however, these two sciences are inextricably tied. Misali Island, a small coralline island in the Indian Ocean, has been largely uninhabited for its entire history, making this coastal interface unique. In this study, Misali Island is used as a study region to demonstrate how natural processes are materializing in the Zanzibar Archipelago. Methods employed, both geological and marine, work to understand the erosional circumstances of Baobab Beach and the inherent effects on local coral reefs. Results show that Misali’s northeastern beachfront is currently under …

Sediment Transport And Geomorphological Evolution In The Northern Gulf Of Mexico, Kelli Moran

LSU Doctoral Dissertations

This dissertation explores the mechanisms driving sediment transport and deposition on the continental shelf and within the bays of the northern Gulf of Mexico via a suite of geophysical methods and sediment cores on a variety of timescales. This dissertation is comprised of three main chapters, each focusing on a different location, environment, and process but tied together using geophysical survey, a thematic focus on geomorphic change and sediment transport within the deltaic cycle and deltaic plain environments, and the implications this change poses for both past and future sediment transport and environmental change in response to sea level change. …

Sediment Delivery To Sustain The Ganges-Brahmaputra Delta Under Climate Change And Anthropogenic Impacts, Jessica L. Raff, Steven L. Goodbred Jr., Jennifer L. Pickering, Ryan S. Sincavage, John C. Ayers, Md. Saddam Hossain, Carol A. Wilson, Chris Paola, Michael S. Steckler, Dhiman R. Mondal, Jean-Louis Grimaud, Celine Jo Grall, Kimberly G. Rogers, Kazi Matin Ahmed, Syed Jo Grall, Kimberly G. Rogers, Kazi Matin Ahmed, Syed Humayun Akhter, Brandee N. Carlson, Elizabeth L. Chamberlain, Meagan Dejter, Jonathan M. Gilligan, Richard P. Hale, Mahfuzur R. Khan, Md. Golam Muktadir, Md. Munsur Rahman, Lauren A. Williams

OES Faculty Publications

The principal nature-based solution for offsetting relative sea-level rise in the Ganges-Brahmaputra delta is the unabated delivery, dispersal, and deposition of the rivers’ ~1 billion-tonne annual sediment load. Recent hydrological transport modeling suggests that strengthening monsoon precipitation in the 21st century could increase this sediment delivery 34-60%; yet other studies demonstrate that sediment could decline 15-80% if planned dams and river diversions are fully implemented. We validate these modeled ranges by developing a comprehensive field-based sediment budget that quantifies the supply of Ganges-Brahmaputra river sediment under varying Holocene climate conditions. Our data reveal natural responses in sediment supply comparable to …

Systemic Analyses Of Radiocarbon Ages Of Coexisting Planktonic Foraminifera, Jörg Lippold, Julia Gottschalk, Jean Lynch-Stieglitz, Matthew W. Schmidt, Sönke Szidat, Andre Bahr

OES Faculty Publications

We compare radiocarbon (¹⁴C) ages of coexisting planktonic foraminifera species from sediment cores VM12-107 and KNR166-2-26JPC from the Equatorial Atlantic Ocean for three time periods (Holocene, Heinrich Stadial 1, last glacial maximum). We find a maximum inter-species difference of 1200 ¹⁴C yr. On average, the ¹⁴C ages deviate by ∼300 yr between Globigerinoides ruber and other species. In most cases, this exceeds the analytical uncertainty range of the measurements and thus renders the choice of species for generating age models as important as sample weight. While modern stratified water-column profiles imply an increase in ¹⁴C …

Laguncularia Racemosa Top-Layer Sediment Microorganism Makeup In Relation To Differing Levels Of Perceived Anthropogenic Impact In Bocas Del Drago, Bocas Del Toro, Panama, Gabrielle Glendening

Independent Study Project (ISP) Collection

As mangrove forests are destroyed by human factors across the earth, many crucial ecological processes that take place in these systems of trees are obstructed. One of the most important roles played by mangroves is their ability to sequester carbon in the sediment, as this storage of carbon helps diminish atmospheric warming. Many sediment microorganisms help in this process of carbon sequestration and play various other vital roles in mangrove ecosystems. Microorganisms in marine sediments can be used to assess the health of the surrounding environment. Past research has found significant differences in sediment microorganism composition, abundance, and diversity in …

A New Model For Predicting The Drag And Lift Forces Of Turbulent Newtonian Flow On Arbitrarily Shaped Shells On The Seafloor, Carley R. Walker, James V. Lambers, Julian Simeonov

Dissertations

Currently, all forecasts of currents, waves, and seafloor evolution are limited by a lack of fundamental knowledge and the parameterization of small-scale processes at the seafloor-ocean interface. Commonly used Euler-Lagrange models for sediment transport require parameterizations of the drag and lift forces acting on the particles. However, current parameterizations for these forces only work for spherical particles. In this dissertation we propose a new method for predicting the drag and lift forces on arbitrarily shaped objects at arbitrary orientations with respect to the direction of flow that will ultimately provide models for predicting the sediment sorting processes that lead to …

New Hampshire Continental Shelf Geospatial Database: Surficial Geology Maps And Sediment Grain Size Data, Larry G. Ward, Zachary S. Mcavoy, Rachel C. Morrison

Data Catalog

The “New Hampshire Continental Shelf Geospatial Database: Surficial Geology Maps and Sediment Grain Size Data” consists of high-resolution surficial geology maps of the continental shelf off New Hampshire to Jeffreys Ledge in the Western Guff of Maine (WGOM) and supporting sediment grain size information. The surficial geology maps cover ~3,250 km² (Figure 1). The maps depict three different classifications based on the Coastal and Marine Ecological Classification Standards (CMECS; FGDC, 2012): Geoforms (major morphologic or physiographic features; Figure 2; Table 1), Geologic Substrate Subclass (Figure 3; Table 2), and Geologic Substrate Group (Figure 4; Table 2). The maps are …

Small-Scale Resuspension And Redistribution Of Surface Sediments In The Northeast Gulf Of Mexico, Austin Harris

Master's Theses

Following the release of ~4.9 million barrels of oil into the Gulf of Mexico from the Macondo wellhead, a vast area of the seafloor contained recently deposited marine sediments contaminated by the oil spill. The initial deposition of these contaminated marine sediments was likely not the end of the journey for the particles. Downslope gravitational processes and events of increased current speed in the deep ocean setting can result in recently deposited sediments to resuspend and be moved laterally with the current flow, increasing the area effected by the oil spill. Erosion experiments performed in a closed-loop resuspension flume were …