Marine Biology Commons^™

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 …

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 …

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 …

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 …

Utilizing Accelerometer Telemetry Tags To Compare Red Snapper (Lutjanus Campechanus) Behavior On Artificial And Natural Reefs, Ethan T. Getz

Theses and Dissertations

The Texas Parks and Wildlife Department Artificial Reef Program has deployed over 2,800 hectares of reefing area composed of petroleum platforms, steel vessels, and concrete. Artificial reefs have been shown to support many important reef fishes such as red snapper (Lutjanus campechanus), however, few studies have compared fish behavior on artificial reefs and natural habitats. We examined activity levels, behavioral patterns and habitat preferences of red snapper over natural reefs, oil platforms and submerged ships. Telemetry tags (Sonotronics model MTT) with tri-axial acceleration range, average depth, and average temperature were programmed to optimize data collection and tag life. …

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 …

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 …

Pelagic Fish Diversity And Density On And Off Restored Oyster Reef Habitat, Danielle Mcculloch

Theses and Dissertations

The heterogeneity provided by structured habitats is important in supporting diverse and dense fish communities. The biogenic reefs created by the native Eastern Oyster, Crassostrea virginica, were once the dominant structural habitat in Chesapeake Bay, and have since declined to less than 1% of historic estimates. Conflicting results on the effects of oyster reef restoration on pelagic fish assemblages make further investigation necessary. Incorporating multiple sampling strategies may help elucidate oyster reef habitat influence on fish assemblages. This study used multi-panel gillnets, hydroacoustic technology, and day-night sampling to describe pelagic fish assemblages on and off oyster reef habitat in the …

Air- Sea Interactions And Ocean Dynamics In The Southwest Tropical Indian Ocean, Jessica Maureen Burns

Theses and Dissertations

The Southwest Tropical Indian Ocean (SWTIO) features a unique, seasonal upward lift of the thermocline, which is known as the Seychelles-Chagos Thermocline Ridge (SCTR; 55°E-65°E, 5°S-12°S). It is known that a high correlation exists between the depth of the thermocline and sea surface temperature (SST; a key ingredient for tropical cyclogenesis). With a particular focus on 2012/2013, this study reveals the dynamic properties of the SCTR that play an important role in the modulation of tropical cyclones in the SWTIO. Phenomena including Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO) are also well correlated to cyclogenesis through changes …

The Influence Of Phytoplankton Size And Community Composition On Carbon Cycling And Planktonic Food Webs In The Sargasso Sea, Bridget Elise Cotti-Rausch

Theses and Dissertations

The Sargasso Sea is a dynamic physical environment located in the western North Atlantic where strong seasonal variability combines with forcing by mesoscale (~100 km) eddies. These drivers determine nutrient, light, and temperature regimes, and ultimate the size, composition and productivity of the phytoplankton community. My general objective was to determine how the structure and function of planktonic communities affected carbon export from the surface ocean in the Sargasso Sea. On four cruises (2011 and 2012; one eddy per cruise), I investigated links between water column structure, plankton community composition, size, and primary production (PP). I then combined PP data …

Behavioral Responses Of Sub-Adult Atlantic Sturgeon (Acipenser Oxyrinchus Oxyrinchus) To Electromagnetic And Magnetic Fields Under Laboratory Conditions, Andrew Mcintyre Iii

Theses and Dissertations

Electromagnetic fields (EMF) produced by high voltage (HV), submarine transmission cables leading from offshore wind energy generation facilities could affect foraging or migratory behaviors of electro-receptive fishes, including endangered Atlantic Sturgeon. However, no published studies have quantitatively evaluated the possible behavioral effects of EMF exposure on sturgeon during residence in coastal waters. This study evaluated behavioral responses by sub-adult Atlantic Sturgeon to electromagnetic and magnetic fields under controlled laboratory conditions. Fabricated EMF generators were used to emulate a range of field EMF conditions that migratory fishes could encounter in proximity to submarine HV sources. Sensor arrays and digital video recorders …

A Comparison Of Computational Methods For Estimating Estuarine Production And Respiration From Diel Open Water Dissolved Oxygen Measurements, Spencer Tassone

Theses and Dissertations

Diel dissolved oxygen (DO) data were used to characterize seasonal, inter-annual, and longitudinal variation in production and respiration for the James River Estuary. Two computational methods (Bayesian and bookkeeping) were applied to these data to determine whether inferences regarding DO metabolism are sensitive to methodology. Net metabolism was sensitive to methodology as Bayesian results indicated net heterotrophy (production < respiration) while bookkeeping results indicated net autotrophy (production > respiration). Differences in net metabolism among the methods was due to low seasonal variation in respiration using the Bayesian method, whereas bookkeeping results showed a strong correlation between production and respiration. Bayesian results suggest a dependence on allochthonous organic matter (OM) whereas …

Molecular Exploration Of Bioavailable Dissolved Organic Matter Across Aquatic Ecosystems, Yuan Shen

Theses and Dissertations

Dissolved organic matter (DOM) in aquatic ecosystems is a large reservoir of reduced carbon that is mostly resistant to degradation. A small fraction of DOM cycles relatively quickly and is biologically utilized on timescales of days to months. This bioavailable DOM (BDOM) supports aquatic food webs, drives major elemental cycles, and is coupled to atmospheric CO2. Despite wide-ranging importance, bioavailability of DOM and its linkages to ecosystem properties (e.g., primary production, nutrients) are poorly characterized, particularly at the ecosystem level. Bioassay experiments are commonly used to determine BDOM, but this approach alters conditions and has limited spatial and temporal coverage. …

Wind Driven Shelf Circulation: Effects Of Shoreline Orientation, Bathymetry, And Surface Cooling, Xiaodong Wu

Theses and Dissertations

The dynamic region extending from the inner- to outer-shelf is the nearshore region where an accurate understanding of the development of cross-shore flows is important as they control the exchange of constituents (e.g., pollutants, larvae, heat and biota) between the coastline and the open ocean. These flows are driven by a variety of forces, including wind and buoyancy. The wind forcing relevant to shelf circulation broadly falls within the synoptic scale of storm events, consisting of frontal systems (cold and warm fronts) and tropical storms. The buoyancy on the shelf is characterized by a vertical stratification or a pronounced cross-shore …

Marine Phosphorus Biogeochemistry Ecological Insights From Analytical Chemistry, Douglas W. Bell

Theses and Dissertations

The supply of phosphorus (P) directly impacts the growth and speciation of marine microbes (i.e., phytoplankton, bacteria, Archaea). In turn, microbial communities shape the magnitude and rate of marine biogeochemical cycles, ultimately affecting global climate and food production. This dynamic reflects the continuum of temporal and spatial scales at which the marine P cycle operates. However, linking multiple scales of cycling remains a consistent challenge. The primary objective of my dissertation was to gain insight into marine P biogeochemistry, by means of analytical chemistry, at the molecular and environmental scales of cycling. The first component of my research was to …

Development Of A Sandwich Hybridization Assay For The Harmful Cyanobacteria Microcystis Spp., Nicole M. Dearth

Theses and Dissertations

Cyanobacteria are responsible for the largest number of harmful blooms (HABs) worldwide. HABs caused by the genus Microcystis pose public health threats because they often occur within close proximity to humans and produce microcystin (hepatotoxin), which can contaminate drinking water and recreational areas. Novel molecular techniques facilitate monitoring, ‘early warnings’ of HAB events, and appropriate management responses. Sandwich hybridization assay (SHA), the technique considered here, directly (no amplification) identifies and quantifies planktonic species using ribosomal RNA (rRNA)-targeted oligonucleotides. This project developed SHA for Microcystis 16S rRNA and validated the assay using laboratory cultures and samples from a multi-specific cyanobacteria bloom …

Assessing The Effects Of The Mud Snail, Ilyanassa Obsoleta, On The Benthic Microalgal Community In A Pristine Saltmarsh, Miranda Gore

Theses and Dissertations

Saltmarshes are among the most productive ecosystems globally. At North Inlet estuary, South Carolina, about one third of the primary production comes from benthic microalgae. During the tidal cycle, mobile microalgae vertically migrate through the upper 3 mm of sediment. At low tide, algae are vulnerable to a variety of grazers, including the mud snail, Ilyanassa obsoleta, which is abundant in tidal creeks. Many species of intertidal snails have been shown to significantly alter the community structure and density of microalgae within the sediment. The purpose of this study was to determine how I. obsoleta affects the benthic microalgae community …

Ménage À Trois In The Atlantic Brief Squid (Lolliguncula Brevis): Prior Presence Affects Mate Choice, Rachel A. Schlessinger

Theses and Dissertations

Lolliguncula brevis given prior presence experienced a significantly greater number of contacts with opposite sex squid than rivals. Males given prior presence also spent significantly more time in proximity to females than rivals. This suggests that for both female and male Atlantic brief squid, having prior presence influences mating behavior.

The Effect Of Depth On Development And Sexual Dimorphism Of The Sonic System In Deep Sea Neobythitine Fishes: The Upper Continental Slope, Heba Ali

Theses and Dissertations

Abstract

Background: Cusk-eels from the subfamily Neobythiitinae are one of the major groups of sound-producing fishes on the continental slope. Sounds have never been recorded from a member of this subfamily, and sonic anatomy is considered a proxy for sound production. As the first part of a study on the effects of depth on sonic anatomy, we examined three relatively shallow species from the upper continental slope.

Methods: Three species (Hoplobrotula armata, Neobythites longipes and Neobythites unimaculatus) were examined for sonic anatomy (skeleton, swimbladder and sonic muscles), and sonic and epaxial muscle fibers were measured for diameter. …

Utilization Of Satellite-Derived Salinity To Study Indian Ocean Climate Variability, Joseph Matthew D’Addezio

Theses and Dissertations

For several decades, researchers have explored Indian Ocean climate variability primarily using numerical models because of a lack of observations. Remote sensing technology has helped overcome this scarcity of observational data, but satellite-derived salinity has only been recently made available by the ESA’s Soil Moisture and Ocean Salinity (SMOS, operating since November 2009-present) and NASA’s Aquarius SAC-D (operated during June 2011-June 2015) satellites. Along with the Lagrangian in situ Argo floats array, these new datasets may be used to validate widely used numerical models, such as the HYbrid Coordinate Ocean Model (HYCOM), and also potentially observe new salinity phenomena that …

Development And Application Of Foraminiferal Carbonate System Proxies To Quantify Ocean Acidification In The California Current, Emily B. Osborne

Theses and Dissertations

The oceanic uptake of anthropogenic carbon has mitigated climate change, but has also resulted in a global average 0.1 decline in surface ocean pH over 20th century known as ocean acidification. The parallel reduction in carbonate ion concentration ([CO32-]) and the saturation state of seawater (Ω) has caused many major calcium carbonate-secreting organisms such as planktonic foraminifera to exhibit impaired calcification. We develop proxy calibrations and down core records that use calcification and geochemical characteristics of planktonic foraminifera as proxies for the marine carbonate system. This study focuses specifically on the surface ocean chemistry of the California Current Ecosystem (CCE), …

Mislabeling Of Commercial Atlantic Cod (Gadus Morhua) Products In Spain, Joshua Helgoe

Theses and Dissertations

The mislabeling of commercial fish products is a pervasive, worldwide problem. Most consumers of seafood are unaware this issue directly affects them and can even have negative impacts on their health. Mislabeling occurs when a product’s label is inconsistent with its content. Although mislabeling can be unintentional, deliberate mislabeling is a more common trend to increase profits and/or bypass fishing regulations - a form of economic fraud. Unfortunately, oversight, enforcement, and research are vastly insufficient in relation to the global scale of the problem. In order to add to the small knowledge base on European mislabeling rates, determine if overfished …

Decadal Salinity Changes In The Oceanic Subtropical Gyres And Connection To Changes In The Global Water Cycle, Bryce Andrew Melzer

Theses and Dissertations

There is evidence that the global water cycle has been undergoing an intensification over several decades as a response to increasing atmospheric temperatures, particularly in regions with skewed evaporation – precipitation (E-P) patterns such as the oceanic subtropical gyres. However, observational data (rain gauges, etc.) can be quite sparse over such areas due to the inaccessibility of open ocean regions. This study utilizes in situ data, reanalysis, and model outputs to infer interannual to decadal scale trends in surface freshwater forcing within remote, evaporation-dominated subtropical regions of the ocean as they pertain to the past and present state of the …

Applicability Of Lidar Technology In Saltmarshes: Landscape-Scale Predictive Models To Local-Scale Biomass Estimation, James Dean Edwards Jr.

Theses and Dissertations

The management of saltmarshes requires detailed knowledge of the underlying processes driving their distribution in both time and space to make appropriate management decisions. With most of the world’s population living in the coastal zone and rising sea levels, one of our most important natural resources in the coastal zone faces increasing threat of collapse. This study uses the current state of Light Detection and Ranging (LiDAR) technology to model and predict saltmarsh distribution at a landscape-scale and provide evidence that a terrestrial laser scanner (TLS) can be used to estimate saltmarsh biomass for inclusion into existing models.

Land cover …

Biodegradation Of Highly Weathered Deepwater Horizon Oil, Joel T. Bostic

Theses and Dissertations

Oil from the Deepwater Horizon (DwH) spill continues to be found on beaches five years post-spill. Understanding the role of microbes in removing DwH oil from sandy beaches is necessary to elucidate the fate of DwH oil in the coastal zone. Oiled sand patties and non-oiled sand were collected from affected beaches five years post- DwH. Biomarkers in oiled sand indicated that sand patties originated from the DwH spill, however the oil was heavily weathered and dominated by oxygenated hydrocarbons. Microbial communities, as measured by phospholipid fatty acids (PLFA), were present on oiled sand patties and distinct from microbes on …

Viruses And Metals In Ocean Food Webs: Top-Down And Bottom-Up Effects Of Marine Viruses And Trace Elements On Marine Picophytoplankton, Brady Robert Cunningham

Theses and Dissertations

Viruses are the most numerous biological entities in the ocean, playing a key role in microbial ecology and biogeochemical cycling. In order to replicate, viruses must first infect a host and then use the host’s cellular machinery to produce new viral particles. Some of the most abundant viral hosts in the subtropical open ocean are picophytoplankton. However, picophytoplankton growth is typically constrained by nutrient availability. In many regions of the ocean, iron (Fe) is only available in very low concentrations causing growth-limitation of picophytoplankton. Interestingly, the interactions between Fe-limitation and viral infection of picophytoplankton have not been extensively studied. This …

Global Methylation Of Dna Among Spartina Alterniflora Clones Differing In Age At North Inlet, Sc, Trenton Agrelius

Theses and Dissertations

“Brown marsh” or “sudden marsh dieback” refers to the rapid death of patches varying in size of Spartina alterniflora. In 2000 following a 100-year record drought, approximately 8,000 hectares of S. alterniflora died along the Louisiana coast, which prompted Louisiana Governor Foster to declare a state of emergency. Other cases have been documented at North Inlet, SC as well as various other marshes along the southeastern United States. Currently, there is much dispute regarding the cause of “sudden marsh dieback” but environmental stress is one of the acknowledged constants across sites. We hypothesized an alternative mechanism in which methylation of …

Developmental Analysis Of Rod And Cone Photoreceptor Architecture In The Retina Of The Green Sea Turtle (Chelonia Mydas), Nikia Lynn Rice

Theses and Dissertations

All sea turtle species are threatened or endangered, some critically so. Vision is key to individual success in sea turtles; they use their vision for sea finding at hatching, foraging and predator avoidance throughout life, and mating and nesting as adults. This research project provides a comprehensive analysis throughout development (the first of kind) of the outer retina of the green turtle, Chelonia mydas. The research project included characterization of the retina biochemically via immunohistochemistry and histologically via light microscopy, both done over the course of development from hatchling through adult. At all stages, the retina was duplex, containing both …

Examining The Sensitivity Of Surface Chlorophyll To Upwelling Events Of Variable Frequency In The California Current System, John Thomas Bartlett

Theses and Dissertations

Eastern Boundary Upwelling Systems (EBUS) spatially encompass approximately 1% of the ocean surface area, but are responsible for nearly 20% of global fisheries production. This significant biological production is primarily attributed to the nutrient-rich waters brought to the euphotic zone through a physical process called upwelling. In an attempt to understand the various physical and biological processes occurring on a wide range of temporal and spatial scales, the California Current System (CCS), one of the major EBUS, has been subject to a multitude of scientific studies over the past several decades. Recent modeling enhancements have enabled researchers to investigate mesoscale …

A Hydrographic Climatology Of The Gulf Of St. Lawrence, Alejandro Frank

Theses and Dissertations

The Gulf of St. Lawrence (GSL) is characterized by a general circulation of an estuarine type, where fresher/lighter water flows seaward above saltier/heavier water flowing landward. In an estuarine regime, the inflowing deep layer water compensate for a loss of mass due to the surface layer outflow. A major element of the GSL estuarine circulation is the coastal buoyancy-driven current fed by the St. Lawrence River discharge. In addition, some surface water is advected into the GSL as a branch of the Labrador Current (LC). Recent climatological changes in the North Atlantic have increased the melting rate of the Greenland …