Life Sciences Commons^™

Evaluation Of Monthly And Seasonal Grazing Rates Of Ilyanassa Obsoleta On Benthic Microalgae In The North Inlet Estuary, Brittany Dearmitt

Theses and Dissertations

The eastern mud snail, Ilyanassa obsoleta, is found at densities of 100’s of individuals m^-2 on soft sediments in the intertidal zones of estuaries. These obligate deposit feeders consume microalgae, detritus, larvae, meiofauna, and macrofauna in the surface layers of sediments with possible trophic impacts on benthic microalgal (BMA) biomass. The goals of this study were to quantify mud snail grazing on BMA biomass, observe the variation in monthly and seasonal grazing rates, and evaluate the relationship between atmospheric temperatures and grazing rates. The sites for this experiment were two mudflats in Oyster Landing, North Inlet estuary, South …

Sensitivity Of Aquatic Organic Matter Degradation To Changing Temperature And Nutrient Conditions In A Coastal Watershed, Curtis John Szewczyk

Theses and Dissertations

The degradation of organic matter (OM) within inland waters plays a pivotal role in the global carbon cycle and quantifying carbon budgets. Here, measurements of dissolved oxygen (DO) decay rates were used to infer the extent and kinetics of OM degradation under variable conditions. The goal of the investigation was to quantify how OM samples within the Waccamaw River watershed, South Carolina, respond to changes in temperature and nutrient availability as a function of their source location and lability. Samples were collected from urbanized stormwater detention ponds and undeveloped upland forested wetland drainages to provide contrasting and distinct OM sources …

Spatial And Temporal Variability In Carbon And Nutrient Concentrations Within The North Inlet Estuary,Sc, Heather Kish

Theses and Dissertations

Coastal wetlands provide numerous ecosystem services, including the ability to sequester and store significant amounts of organic carbon (so-called “blue carbon”). Variability in carbon storage within marshes represents a major information gap in understanding and quantifying the role saltmarshes play in the global carbon cycle. This study quantified decadal and small-scale variability in carbon and nutrient concentrations across tidal inundation gradients in the relatively pristine North Inlet Estuary, South Carolina. Sampling took place within two segments of the marsh platform of Crab Haul Creek, the landward-most basin within North Inlet. In the summer of 2020, a total of 200 sediment …

Characterizations Of Dissolved Organic Carbon At Hydrothermal Systems Of The Midcayman Rise, Aaron Mau

Theses and Dissertations

Marine dissolved organic carbon (DOC) is a carbon reservoir comparable in size to all atmospheric CO2 and is composed primarily of refractory material which can be thousands of years old. Circulation through hydrothermal systems has been demonstrated to profoundly alter this material, but the mechanisms that lead to addition, removal, and alteration of DOC are poorly understood. Consequently, the contribution of hydrothermal systems to organic carbon cycling in the deep ocean – and the biological and geochemical processes exhibited at different venting environments – remain highly uncertain.

In January 2020, samples were collected from two hydrothermal vent fields at the …

Caribbean Yellowtail Snapper Ocyurus Chrysurus: Filling In Critical Gaps In Research For Life History And Novel Ageing Validation Utilizing Δ14C, Sarah Zajovits

Theses and Dissertations

Yellowtail snapper Ocyurus chrysurus is an important fisheries species in the US Caribbean; in waters of Puerto Rico, it ranks second for reef fishes in terms of annual total commercial landings. However, a paucity of information exists concerning basic life history information for Caribbean yellowtail snapper populations. This study provides the first comprehensive documentation of age, growth, and reproductive biology of yellowtail snapper from the Caribbean and is the first to directly validate age estimation in this species. Sampling of 1731 yellowtail snapper occurred in Puerto Rico and the U.S. Virgin Islands during 2013-2021 from fisheries-dependent and –independent efforts. Fish …

Dissolved Nitrogen Cycling In The Eastern Canadian Arctic Archipelago From Stable Isotopic Data, Holly Westbrook

Theses and Dissertations

Climate change is expected to drastically alter the input of inorganic nitrogen (N) sources in the Eastern Canadian Arctic Archipelago (ECAA) with increasing discharge from glacial meltwater and permafrost thawing. Since dissolved inorganic N is generally depleted in surface waters, dissolved organic N (DON) could represent a significant source of nutrients limiting primary production in Arctic ecosystems. Yet, few DON data for this region exist. We analyzed stable isotopes (δ¹⁵N and δ ¹⁸O of DON and NO₃-) to investigate dissolved nitrogen cycling in glacial rivers and marine surface samples collected in the ECAA during summer …

Fortnightly Effects Of Urea Additions On Cyanobacteria In A Stormwater Detention Pond, Halley Carruthers

Theses and Dissertations

Increased urban and suburban population growth along the South Carolina (SC) coast has led to a rise in impervious surfaces, altering the course of stormwater runoff events. The construction of stormwater detention ponds (SDPs) is one of the many ways to best mitigate the flow of this water. In their function as natural pollutant traps, SDPs often contain increased levels of nutrients (nitrogen, N and phosphorus, P), which can lead to eutrophication. Under these high eutrophic conditions, primary production is overstimulated, and the formation of phytoplankton blooms, including harmful algal blooms (HABs) can occur. In recent decades, the forms of …

Zooplankton Community Structure And Grazing Within A Stormwater Detention Pond In Coastal South Carolina, Kristen Laccetti

Theses and Dissertations

Stormwater detention ponds (SDPs) on the coast of South Carolina have become increasingly prevalent as the area experiences rapid urbanization. SDPs are man-made reservoirs implemented to minimize pollution inputs into receiving waters and are home to diverse biota, including zooplankton. Zooplankton are a good water quality indicator due to their quick response times and trophic regulators of phytoplankton through grazing. Zooplankton and phytoplankton interactions in stormwater detention ponds are an essential component for understanding plankton community dynamics in SDPs. This purpose of this study was to determine the seasonal variability in zooplankton community composition and grazing rates at 14-day intervals …

Ocean-Atmosphere Interactions During Intraseasonal Oscillations In The Northern Indian Ocean, Heather Leigh Roman-Stork

Theses and Dissertations

The Indian Ocean and the monsoon system are dynamically complex. In the Bay of Bengal (BoB) and southeastern Arabian Sea (SEAS), surface circulation is strongly influenced by the monsoons and notable local eddying that modulates the East India Coastal Current (EICC). In this study, the role of freshwater transported from the BoB into the SEAS in determining both the timing of monsoon onset and the strength of the ensuing monsoon is examined. It is found that the long-term decrease in moisture flux from the sea surface and freshwater transport into the SEAS, along with a rise in upper ocean heat …

Spatiotemporal Dynamics Of Benthic Microalgae In South Carolina Shelf Sediments, Sarah N. Zaunbrecher

Theses and Dissertations

Benthic microalgae (BMA) play essential roles in food webs and regulating nutrient exchange at the sediment-water interface in continental shelf ecosystems. However, shelf BMA are not widely studied due to the difficulties sampling the upper few millimeters of shelf sediments. A few published studies have highlighted the high spatiotemporal distribution of BMA, but detailed explanations for this known variability are limited. The objectives of this study were to quantify BMA biomass variability on scales of cm to km and relate these measurements to in situ nutrient concentrations, sediment grain size, in situ irradiance, depth, and other environmental factors. Water and …

Circulation Changes In The Arctic Ocean And Subarctic Seas And Their Connections To The Global Ocean And Climate, Rachel Elizabeth Nichols

Theses and Dissertations

Salinity and freshwater fluxes are important tools for monitoring the amount of freshwater entering and exiting the Arctic Ocean. Satellite-derived salinity provides a way to study surface advective freshwater fluxes; however, sea ice contamination, among others, remains an obstacle in the accuracy and reliability of these measurements. In this study, salinity and surface freshwater fluxes are calculated using NASA’s Soil Moisture Active Passive (SMAP) and the ESA’s Soil Moisture Ocean Salinity (SMOS), Argo, and the European Centre for Medium-Range Weather Forecast’s Ocean Reanalysis version 4 (ORAS4). ORAS4 compares well to Argo in the subarctic seas and is used for comparison …

New Approaches To Understanding Mjo Dynamics, Casey Shoup

Theses and Dissertations

The Madden-Julian Oscillation (MJO) is a highly air-sea coupled phenomenon and is the dominant mode of intraseasonal variability in the tropics. It is easily discernible in satellite-derived sea surface salinity (SSS), which varies as a direct result of MJO precipitation from the convectively active to suppressed phases. Negative (positive) SSS anomalies are associated with the active (suppressed) phase of the MJO. We find that all three available satellite salinity missions (ESA’s Soil Moisture Ocean Salinity (SMOS); NASA’s Aquarius/SAC-D, and NASA’s Soil Moisture Active Passive (SMAP)) are capable of capturing the MJO SSS signal and that the near-equatorial SSS response is …

Dynamics Of The Loop Current System And Its Effects On Surface And Subsurface Properties In The Gulf Of Mexico, Richard James Brokaw

Theses and Dissertations

Surface circulation in the Gulf of Mexico is dominated by the Loop Current System (LCS), including the Loop Current (LC) and its associated eddies. The Gulf of Mexico (GoM) also displays long-term surface gradients of temperature and salinity due to climatological features including the intrusion of warm, saline waters from the Caribbean Sea and the seasonal deposition of freshwater from the Mississippi River System caused by seasonal increases in snow melt and precipitation over the watershed. This research aims to increase the understanding of the LCS through the investigation of its relationship with these surface gradients. A classification system of …

Influence Of Stormwater Management On Oxygen Demand And Organic Matter Cycling In Urbanizing Headwater Catchments, Kelly Mccabe

Theses and Dissertations

Excessive organic matter (OM) is driving declining dissolved oxygen (DO) concentrations in coastal ecosystems, worldwide. The quantity, source, and composition of OM transported to coastal ecosystems via stormwater runoff has been altered by land use changes associated with urbanization and subsequent headwater alterations that accompany urban stormwater management. To understand the role of stormwater runoff in the decline of coastal DO, biochemical oxygen demand (BOD) was determined for samples collected during rain events from the outfalls of a variety of stormwater infrastructure with watersheds spanning a range of development. Measurements of particulate and dissolved carbon and nitrogen and chlorophyll-a concentrations …

Adjustment Of A Coastal Buoyant Outflow Under Tidal And Wind Forcing, A K M Nahid Hasan

Theses and Dissertations

The discharge of brackish water from estuaries typically forms distinct coastal plumes, often visible through their color signature due to sediment load and particulate matter from rivers. The processes of mixing and dispersion of coastal plumes are subjected to natural variations in the magnitude and timing of freshwater inflows, tides and meteorological conditions. This study presents shipboard observation of the bulge region of a buoyant plume off Winyah Bay, SC. The observation comprises downward looking 600 and 1200 kHz ADCP (Acoustic Doppler Current Profiler) and CTD measurements. Along with standard CTD casts, water samples were collected to analyze and determine …

Salt Marsh Health And Biomass Responses To A Changing Environment, Gwen Joelle Miller

Theses and Dissertations

Coastal salt marshes are important ecosystems not only for their aesthetic beauty but also for their ecosystem services that they provide including improving water quality, providing protection from storm surges and hurricanes, and carbon sequestration. With climate change, including drought, warmer temperatures and sea-level rise, these systems are going to be impacted. Understanding how salt marshes will respond, or already have responded, to climate change will help us be better prepared for the future. By scripting a model to project how marshes may migrate with sea-level rise, I discover that salt marshes within Beaufort and Jasper counties, South Carolina will …

Larval Fish Mortality And Vertical Chlorophyll Structures: Reexamination Of The Stable Ocean Hypothesis In The Southern California Current, Brendan D. Turley

Theses and Dissertations

The natural mortality of fishes is an important component for understanding population dynamics. The larval stages of pelagic fishes living in the open ocean are particularly vulnerable to high rates of mortality, and fluctuations in these rates are thought to exert a large influence on the number of fish maturing into the spawning population. Early stage larval fishes are thought to undergo a critical period after hatching when they must find food or succumb to starvation. While the availability of suitable food for larval fishes is, on average, too low in the open ocean to support survival, patchy distributions of …

Energetic Consequences Of Human Impacts For Bioindicator Atlantic Ghost Crab (Ocypode Quadrata), Mustafa Remzi Gül

Theses and Dissertations

Human activities have caused notable changes in ecosystems globally over the past century, which cause substantial ecological issues. The degree of these ecological issues is often investigated using the responses of bioindicator species. Bioindicator species often reduce their population densities and individual sizes as a response to the human disturbance. Observing these variations in the demographics is often an effective way to measure the strength of the ecological changes. However, they do not provide any mechanistic reason (s) for the shifts in the demographics, which is important for making predictions about responses of the species to the future conditions. Therefore, …

The Impacts Of Episodic Floods, Droughts, Turbidites On Organic Carbon Burial Over The Past 2,000 Years In The Santa Barbara Basin, California, Caitlyn Sarno

Theses and Dissertations

Over the past several millennia, Southern California has experienced episodic climate that have influenced the magnitude and composition of terrestrial and marine material that ultimately reaches ocean sediments. Here, we analyze elemental concentrations, stable isotopes, and n-alkane lipids as tracers of terrestrial and marine sources in drought, turbidite, and flood horizons from a well-dated sediment core in the Santa Barbara Basin (SBB) that spans the last 2,000 years. Stable isotopes (δ13C and δ15N), indicate that more terrestrial organic carbon (OC) input occurred during floods relative to non-event periods, while bulk C/N ratios remained relatively constant (~10). Long chain n-alkanes, (C27, …

Upper Ocean Dynamics And Mixing In The Arabian Sea During Monsoons, Corinne Beverly Trott

Theses and Dissertations

The Indian summer monsoon is a complex, nonlinear phenomenon involving atmospheric, oceanic, and land-based interactions from June through September. During this period, a strong low-level jet known as the Findlater Jet develops over the western Arabian Sea, advecting seasonally high quantities of warm, moist air to the Indian subcontinent, leading to the largest precipitation rates on the planet. The winds associated with the Findlater Jet seasonally strengthen the Arabian Sea eddy field, known for its intensity and variability. Comparison between the eddies in the western Arabian Sea during monsoon regimes of varying intensities revealed more high-amplitude eddies in strong (high-rainfall) …

Impacts Of Natural And Anthropogenic Colonized Habitats On The Range Shifting Mangrove Tree Crab (Aratus Pisonii), Zachary John Cannizzo

Theses and Dissertations

Mis-matches in climate-mediated shifting rates cause the ranges of some species to become decoupled from their historic ecosystem, leading to the colonization of ecosystems they have not previously inhabited. When this occurs, the shifting species may experience suboptimal conditions which challenge its ability to persist and expand into the novel ecosystem. However, within the colonized ecosystem, shifting species may encounter artificial habitat analogues: artificial habitats that more closely resemble the species’ historic ecosystem than the surrounding habitat and which mitigate some of the negative impacts experienced elsewhere in the novel ecosystem. Despite their importance to the ecology, life history, and …

On The Scattering Of Topographically Modified Semidiurnal Kelvin Waves Into Internal Waves, Tianyi Zhang

Theses and Dissertations

Semidiurnal tides propagate along continental shelves as a Kelvin wave mode. On wide continental shelves, the shelf topography modifies the Kelvin wave mode into a hybrid Kelvin-edge wave (HKEW), with features of a zero mode edge wave. Its free surface structure and alongshore energy flux concentrate on the shelf, and are sensitive to changes in the shelf width. When a propagating HKEW encounters an alongshore change of shelf width, the adjustment of wave structures results in the scattering of the incident wave into other wave modes, including barotropic and baroclinic Poincaré waves radiating offshore. These dynamics are studied using the …

Restoration Of Visual Performance And Opsin Expression Within The Retina During Eye Regeneration In The Florida Fighting Conch (Strombus Alatus), Jamie M. Clark

Theses and Dissertations

Conch are slow-moving, herbivorous, marine gastropods that possess prominent camera-type eyes at the ends of long, flexible stalks. Compared to the eyes of other gastropods, those of conch are large (up to 1.5 mm in diameter) and have sophisticated optics that include a lens with a graded refractive index. Conch also have a remarkable ability to regenerate eye tissue: after an eye is lost, a new eye will develop to take its place within weeks. Eye regeneration in conch appears to occur rapidly compared to eye regeneration in other gastropods. Despite our knowledge of the complexity and regenerative abilities of …

The Role Of Enso On The Agulhas Current Leakage Region, Morgan Lauren Paris

Theses and Dissertations

The southern end of the African continent marks the division between the Atlantic Ocean and the Indian Ocean where warm, saline waters propagate into the Atlantic Ocean in the form of rings, eddies, and filaments. These warm, saline waters released during the retroflection of the Agulhas Current are referred to as Agulhas leakage. The Agulhas Current is a poleward flowing western boundary current that forms the limb of the winddriven anti-cyclonic circulation of the south Indian Ocean. The current originates south of Madagascar fed by the Mozambique Channel and the East Madagascar Current. Smallscale variations have been identified in Agulhas …

Influence Of Energy Availability On The Carbon Isotopes Of Methane And Biomarkers During Hydrogenotrophic Methanogenesis, Tran Nguyen

Theses and Dissertations

Signatures of organic molecules in the environment are widely used to identify microbial metabolic processes and to track the cycling of carbon. The lipid biomarkers of methane cycling archaea are of particular interest as they are unique, preserved over geologic time scales, and reflect processes that impact an important greenhouse gas. Their isotopic compositions have been used to distinguish regions where archaea produce and anaerobically consume CH4. Previous work has demonstrated that energy availability impacts the stable carbon isotopes of CH4 during microbial synthesis from H2 and CO2. Here, we investigated whether this relationship could be extended to lipids and …

Determining The Subsidence Rate Of The Cascade Seamount Using Strontium Isotope Stratigraphy, Sarah L. Vorsanger

Theses and Dissertations

The Cascade Seamount is a wave-planated feature located on the microcontinent of the East Tasman Plateau (ETP). The minimum subsidence rate of the Seamount and the ETP can be estimated by dividing the present-day depth of the wave-cut surface (640 m) by the age of Cascade Seamount basalts as determined by potassium-argon (K-Ar) dating (33.4 and 36 Ma). This approach yields a subsidence rate of 18 m/Myr. However, a significantly more rapid subsidence rate of the ETP since the Eocene-Oligocene transition has been proposed based on sedimentological and biostratigraphic techniques. The late Eocene paleodepths determined by Stickley et al. (2004) …

Climate Metric Coherence: Stationarity Of The Relationships Between North Pacific Climate Indices And Ecological Processes In The Gulf Of Alaska, Michael Opiekun

Theses and Dissertations

The Pacific Decadal Oscillation (PDO) has been used to characterize the dominant basin-scale climate variability, in the North Pacific. The PDO index has been correlated to Pacific salmon (Oncorhynchus spp.) population dynamics in the Gulf of Alaska (GOA) during the late 1900s, but the stationarity of the statistical relationships between salmon production and the basin-scale index (and between the regional physical processes and the basin-scale index) has not been quantified. A change in the relationship between the PDO and salmon catches has been noted during the late 1980s, motivating further investigation of variability in climate and ecosystem properties during this …

Phenotypic Response Of Marine Cryptophytes To Varying Spectral Irradiance, Kristin M. Heidenreich

Theses and Dissertations

Cryptophytes are eukaryotic algae found in a variety of aquatic ecosystems, that vary in the color of light available for photosynthesis. This algal division displays a diversity in necessary photosynthetic pigments, possessing either phycoerythrin (Cr-PE; “pink”) phycocyanin (Cr-PC; “green”). According to the theory of complementary chromatic adaptation, this diversity should help maximize absorption of light within natural environments. The objective of this study was to determine if pigmentation related to growth performance in environments of differing spectral irradiance. Eight species of marine cryptophytes (5 Cr-PE and 3 Cr-PC species) were grown under four different spectral light environments. Growth rates, cellular …

Causes And Consequences Of Individual Phenotypic Differences In Brachyuran Crabs With A Focus On Behavior, Benjamin A. Belgrad

Theses and Dissertations

Individual variation defines almost every morphological, physiological, and behavioral aspect of populations and is a fundamental component of many ecosystem processes. Recent work indicates that accounting for these individual differences can enhance our ability to predict community responses to environmental disturbances which is becoming increasingly important in an era of extraordinary global change. However, our understanding of how different individual characteristics are connected to each other and governed by the environment remains limited.

This study sought to evaluate the relationship between individual behavior, physiological condition, and local habitat for Brachyuran crabs as well as the subsequent strength of their predator-prey …

The Energetic Consequences Of Temperature Variation And Sequential Autotomization For The Stone Crab, Menippe Spp., Eric R. Hancock

Theses and Dissertations

The stone crab, Menippe spp., is harvested in a claw only fishery along the Gulf and southeastern Atlantic coasts of the United States. As climate change continues to warm these areas, crabs are forced to cope with higher water temperatures and lower dissolved O2 concentrations. These altered environmental conditions may influence crab energetics by altering both energy intake and expenditure. To inform fishery sustainability as well as prepare for a potential range expansion of the crab, this study investigates the energetic intake and expenditure of individual stone crabs. Crabs were found to respire 80 and 69% more following the loss …