Oceanography Commons^™

Seasonal And Geologic Controls On Submarine Groundwater Discharge-Derived Nutrient Fluxes To Two Coastal Embayments, Moira Taylor, Joseph J. Tamborski, Aaron Alorda-Kleinglass, Nathaniel Maynard

OES Faculty Publications

Submarine groundwater discharge and porewater exchange are critical but often overlooked sources of nutrients to coastal systems. This study investigates how sediment permeability and summer-winter seasonal dynamics influence the magnitude and biogeochemistry of nutrient fluxes from submarine groundwater discharge and porewater exchange. Reaction rates in the subterranean estuary were used to identify the transformations and drivers of nutrient loading in two geologically distinct embayments in the U.S. East Coast: the highly permeable Peconic Bay estuary (NY), and the surficially fine-grained coastal embayments of the southern Delmarva Peninsula (VA). We applied radium isotope mass balances to distinguish total submarine groundwater discharge …

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 …

Contribution Of Non-Linear Internal Waves To Marine Net Primary Production Has Been Underestimated, Xiaoju Pan, Tung-Yuan Ho, George T. F. Wong, Jen-Hua Tai, Shoude Guan, Fuh-Kuo Shiah

OES Faculty Publications

Field observations in the northern South China Sea (NSCS) indicate that elevated concentrations of chlorophyll a (Chl_a) associated with non-linear internal waves (NIWs) were more pronounced in the subsurface than at the sea-surface. At a given surface Chl_a, the vertically integrated Chl_a in an NIW-active area was 45% higher than that in an area where the NIW activities were minimal. As a result, net primary production (PP_eu) estimated from surface Chl_a from remote sensing by using the current Chl_a-based PP_eu model (e.g. VGPM) would have underestimated the true value by the same amount. If this correction is …

Visualizing The Barely Detectable: Particle Characteristics Of The Elusive Aquatic Gel Phase In The Northeastern Subtropical Atlantic, Huanqing Huang, María Couret, Santiago Hernández-León, Alexander B. Bochdansky

OES Faculty Publications

Marine gels constitute a large yet poorly explored ocean carbon pool. Shadow imaging was tuned to detect particles at two sensitivity levels: high–optical density particles (HODP), resembling the particles captured by most imaging systems, and low–optical density particles (LODP), representing a vastly more abundant and gel-dominated pool. This method enabled us to map and characterize a portion of oceanic gels without filtration and staining. In the subtropical northeast Atlantic, LODP outnumbered HODP of the same size by one or two orders of magnitude. Morphology and particle number spectra differed greatly between the two pools, with LODP showing greater morphological homogeneity …

Aquatic Macrophytes As Nature-Based Solutions: Challenges And Opportunities Across Inland And Coastal Waters, Morgan Botrel, Roxane Maranger, Lindsay L. Trottier, Mathieu Cusson, Lars L. Iverson, Fanny Noisette, Christian Nozais, Katrine Turgeon, Andrea Bertolo, Thibaud André-Alphonse, Simon Bélanger, Arthur De Grandpré, Jean-Olivier Goyette, Sabine Hilt, Ladd Johnson, Valérie Langlois, Martin Laporte, Félix Lauzon, Brigitte Légaré, Anne Ola, Marie-Pomme Presne-Poissant, Matthieu Prugne, Caroline Susini, Richard Zimmerman

OES Faculty Publications

Macrophytes are foundation species whose use as nature-based solution (NbS) in aquatic ecosystems can help reduce climate change impacts while mitigating biodiversity loss. The discrepancy in research and application of macrophytes as NbS across inland and marine coastal ecosystems is an opportunity to expand the concept and learn from different approaches. We report on an initiative uniting marine and freshwater scientists that compared knowledge on macrophytes as NbS across realms, identified advances and gaps in their use, and synthesized challenges and opportunities for application. We conducted a bibliometric analysis and an expert participatory exercise around recent review papers. We reveal …

Revisiting The Life Cycle Of Margalefidinium Polykrikoides Group Iii, Eduardo Pérez-Vega, Kenneth N. Mertens, Pjotr Meyvisch, Margaret R. Mulholland

OES Faculty Publications

Dinoflagellates produce cysts as a strategy to withstand environmental stressors, with nutrient depletion generally considered a key trigger for cyst production. Resting cysts are thick-walled, typically composed of one to several layers, and characterized by a prolonged dormancy period. In contrast, pellicle cysts possess a thin, single wall and exhibit no dormancy or a markedly shorter dormancy than resting cysts of the same species. Margalefidinium polykrikoides produces pellicle and resting cysts, whereas its congener, M. fulvescens, has been shown to produce pumpkin-like structures. Using phase-contrast microscopy, time-lapse microscopy, FlowCam, and attenuated total reflection Fourier transform infrared microspectroscopy (ATR μ-FTIR), …

The Effects Of A Microplate On Plume-Ridge Interactions: Constraints From Comparing Easter And Juan Fernandez Microplates In The Eastern Pacific Ocean, Katherine Ames, Jennifer Georgen

OES Faculty Publications

This study investigates the nature of plume-ridge interactions near a tectonic microplate using mantle Bouguer anomaly (MBA) gravity calculations. The focus of this investigation is a comparison of the Easter and Juan Fernandez microplates, which are located in the eastern Pacific Ocean along the Pacific, Nazca, and Antarctic plate boundaries. The microplates have several similar characteristics, including general size, time of formation, and clockwise rotation within the larger bounding mid-ocean ridge systems. Unlike the Juan Fernandez microplate, however, the Easter microplate is located near a mantle plume (Easter/Salas y Gomez). Previously published geochemical data suggest that material from this plume …

Remote Sensing Of Particulate Organic Carbon And Phytoplankton Carbon In The Northern South China Sea, Xiaoju Pan, Tung-Yuan Ho, George T. F. Wong, Jen-Hua Tai, Lijuan Nie

OES Faculty Publications

Surface concentrations of particulate organic carbon (POC) and phytoplankton carbon (C_phy) in the northern South China Sea (NSCS) have been assessed successfully by remote sensing with appropriate regional tuning. Match-up comparisons between satellite derivations and field observations showed uncertainties of ± 28.5% for POC and ± 37.0% for C_phy. The satellite-derived climatological distributions are consistent with previous reports. In the open NSCS where phytoplankton growth is controlled primarily by the convective overturn, both POC and C_phy are higher in winter, associating with the effect of stronger northeast monsoons and surface cooling, than in summer, when …

Geographic Variation In Proteomic Responses To Ocean Acidification In A Cold-Water Coral (Balanophyllia Elegans), Keana A. Richmond

Cal Poly Humboldt theses and projects

In the face of a rapidly changing climate, assessing organismal responses to future stressors in the context of current, natural exposure to stress could provide key insights to understanding marine ecosystem resilience. I used Balanophyllia elegans, a cold-water, solitary, azooxanthellate coral as a model to better understand how varying oceanographic conditions across its geographic range have shaped its ability to tolerate and potentially adapt to current and future ocean acidification conditions. I collected B. elegans individuals from four sites across 2,500km of their range and subjected them to two pH treatments to investigate site-specific protein expression in response to …

Temporal Patterns Of Storm Surges: Event-Identification, Clustering, And Count Modeling, Ariadna Martin Oliva

Graduate Studies Theses and Dissertations 2026

Coastal regions face compounding risks when extreme events strike in rapid succession, yet most statistical frameworks treat such events as independent, a simplification that can critically underestimate hazard. This thesis addresses that gap through three interconnected contributions focused on the temporal clustering of storm surges at the global scale. A new automated method is developed to extract independent storm surge events from continuous tide gauge records. By leveraging event correlations and a soft-margin approach that accounts for local variability, the method identifies characteristic event durations across 1,485 global tide gauge stations, revealing the influence of both local site conditions and …

Multi-Satellite Image Matching And Deep Learning Segmentation For Detection Of Daytime Sea Fog Using Gk2a Ami And Gk2b Goci-Ii, Jonggu Kang, Hiroyuki Miyazaki, Seung Hee Kim, Menas Kafatos, Daesun Kim, Jinsoo Kim, Yangwon Lee

Institute for ECHO Articles and Research

Traditionally, sea fog detection technologies have relied primarily on in situ observations. However, point-based observations suffer from limitations in extensive monitoring in marine environments due to the scarcity of observation stations and the limited nature of measurement data. Satellites effectively address these issues by covering vast areas and operating across multiple spectral channels, enabling precise detection and monitoring of sea fog. Despite the increasing adoption of deep learning in this field, achieving further improvements in accuracy and reliability necessitates the simultaneous use of multiple satellite datasets rather than relying on a single source. Therefore, this study aims to achieve higher …

Stability Analysis Of Thermohaline Convection With A Time-Varying Shear Flow Using The Lyapunov Method, Kalin Kochnev

Honors Scholar Theses

This work applies the Lyapunov method to identify instabilities and compute the growth rate of a linear time-varying system. The linear system studied describes cold fresh water on top of hot salty water with a periodically time-varying background shear flow. A time-dependent weighting matrix is employed to construct a Lyapunov function candidate. The resulting linear matrix inequalities are discretized in time using the forward Euler method. As the number of temporal discretization points increases, the growth rate predicted by the Lyapunov method or Floquet theory, used for comparison, will converge to the same value obtained from numerical simulations. Furthermore, the …

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 …

Understanding Enso Through Mathematical Models, Maria I. Sanchez Muniz

Open Educational Resources

This assignment introduces students to conceptual models of the El Niño–Southern Oscillation (ENSO) and guides them through a structured investigation of their physical and mathematical foundations. Students analyze the recharge–oscillator and delayed–oscillator frameworks, explore how differential equations capture ocean–atmosphere interactions, and evaluate parameter-driven changes in oscillatory behavior. A key component of the work is the guided use of generative AI as a research tool: students employ AI models to locate peer-reviewed literature, interrogate model extensions, and refine their understanding of complex mechanisms, while synthesizing all final explanations in their own words. By blending classical climate modeling with modern AI-supported inquiry, …

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 …

Coupled Machine Learning Models: Combining Observations And Numerical Analysis In A Physics-Regularized Approach, Austin B. Schmidt

LSU New Orleans Theses and Dissertations

This dissertation investigates surrogate modeling for fixed-location environmental forecasting using novel data-combination techniques. The work surveys the landscape of observational measurements and numerically generated data, identifying similar research and gaps in current methodologies. The ratio-coupled training framework is introduced to combine two data sources per predicted feature through a tunable parameter that weights training signal strength. An optimization scheme is developed to simultaneously tune surrogate weights and the coupled signal ratio, allowing relative influence between signals to act as an explicit regularizer. Three case studies demonstrate the methodology and approach in a variety of contexts. The first study is based …

Isolation Of The 2019 Bonnet Carré Spillway Effects On The Habitat Suitability Of Brown Shrimp (Farfantepenaeus Aztecus) And Blue Crab (Callinectes Sapidus) Using A Modeling Approach, Mallory Dyson

Master's Theses

In 2019, an unprecedented flood year, the Bonnet Carré Spillway (BCS) was opened on two separate occasions (February 27^th to April 11^th, and May 10^th through July 27^th) diverting a volume 6 times the volume of Lake Pontchartrain into the surrounding coastal waters of Louisiana, Mississippi, and Alabama. The goal of this research was to determine the spatio-temporal influence of these freshwater releases on two economically and ecologically important species (Farfantepenaeus aztecus and Callinectes sapidus) with variable responses to salinity and temperature depending on the age class. The Habitat Suitability Index (HSI) …

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 …

A Generational Analysis Of Psychological Motivators Influencing Seafarer Retention, Perisah Tahanci

The Plymouth Student Scientist

Seafarer retention is a growing concern amid increasing global demand for skilled maritime officers. This study investigates the generational differences in psychological motivators influencing seafarer retention, where ‘psychological motivators’ encompass the cognitive factors, including mental and physical wellbeing, work-life balance, compensation, working conditions, and external factors, that shape retention intentions. A cross-sectional survey (n=214) combined quantitative and qualitative analyses to systematically assess how the perceived importance and experience of these factors vary across Generation Z, Millennials, Generation X, and Baby Boomers.

The findings reveal that significant generational differences exist across most factors, particularly in work-life balance and mental wellbeing, in …

What Environmental Circumstances Generate Hazardous Wave Overtopping Conditions For Infrastructure Disruption: Dawlish (United Kingdom) Case Study, Zbigniew Tomasz Zielonka

The Plymouth Student Scientist

Coastal infrastructure faces increasing threats from wave overtopping due to climate change, rising sea levels, and intensifying storms. This research investigates the environmental conditions that drive hazardous wave overtopping using Dawlish, a vulnerable section of the UK’s railway, as a case study. Understanding these conditions is essential for improving knowledge, developing effective mitigation strategies, and enhancing the resilience of shoreline defences against future challenges. Using one-year observations from WireWall instruments, offshore wave buoy, and meteorological data, the research applies a Random Forest model to assess the influence of metocean conditions on overtopping. The results indicate that wave height, tidal level, …