Life Sciences Commons^™

The Impact Of Coastal Phytoplankton Blooms On Ocean-Atmosphere Thermal Energy Exchange: Evidence From A Two-Way Coupled Numerical Modeling System, Jason K. Jolliff, Travis A. Smith, Charlie N. Barron, Sergio Derada, Stephanie C. Anderson, Richard W. Gould, Robert A. Arnone

Faculty Publications

A set of sensitivity experiments are performed with a two-way coupled and nested ocean-atmosphere forecasting system in order to deconvolve how dense phytoplankton stocks in a coastal embayment may impact thermal energy exchange processes. Monterey Bay simulations parameterizing solar shortwave transparency in the surface ocean as an invariant oligotrophic oceanic water type estimate consistently colder sea surface temperature (SST) than simulations utilizing more realistic, spatially varying shortwave attenuation terms based on satellite estimates of surface algal pigment concentration. These SST differences lead to an similar to 88% increase in the cumulative turbulent thermal energy transfer from the ocean to the …

Assimilating Altimetric Data Into A South China Sea Model, Chau-Ron Wu, Ping-Tung Shaw, Shenn-Yu Chao

Faculty Publications

Sea surface heights from the TOPEX/Poseidon altimeter are assimilated into a three-dimensional primitive equation model to derive the circulation in the South China Sea. With data assimilation the model resolves not only the basinwide circulation but also a dipole off Vietnam and a low/high feature near the Luzon Strait. Mesoscale features are missing in the simulation without data assimilation because of poor resolution in the wind field and inadequate knowledge of the transport through the Luzon Strait. Compared to the case without data assimilation, data assimilation reduces the root mean square error between the simulated and observed sea surface heights …

A Time Series Analysis Method Using Hidden Variables For Gene Network Reconstruction, Xi Wu

Dissertations

The DNA microarray technology can be applied to obtain time series data which contains thousands of genes and tens of time points. When confront the great amount of data points a fast and effective method must be constructed to extract useful information. The assumption that the interactions between genes are static in the time series data is made. After made the assumption how to reconstruct those interactions becomes a difficulty problem. Since the underlying interactions between genes are complicated, which involve transcription, translation and protein-protein interaction, to construct a model from physicochemistry is almost impossible/effortless. The popular methods constructed from …

Fluorescence And Size Characterization Of Dissolved Organic Matter In Riverine And Sea Waters In The Northern Gulf Of Mexico, Zhengzhen Zhou

Dissertations

Riverine export of dissolved organic matter (DOM) is an important component in marine carbon budget but the composition and phase partitioning are poorly quantified. Monthly water samples were collected from the lower Mississippi and Pearl rivers between January 2009 to August 2011 for DOM characterization using the fluorescence excitation emission matrix (FluoEEM) technique, coupled with parallel factor analysis (PARAFAC), and flow field-flow fractionation technique. DOM in the Pearl River showed higher dissolved organic carbon (DOC) concentration, temporal fluctuation, and aromaticity, reflecting instantaneous inputs of DOM from local soil and plant litter. In contrast, DOM in the Mississippi River exhibited lower …

Marine Fungi Of U.S. Gulf Of Mexico Barrier Island Beaches: Biodiversity And Sampling Strategy, Allison Kathleen Walker

Dissertations

Marine fungi are an important but often overlooked component of marine ecosystems. Primarily saprotrophic, they are vital to coastal nutrient cycling processes and food webs. However, basic marine fungal distribution data are lacking in many parts of the world, as is knowledge of the sampling intensity required to characterize the biodiversity of these communities. The roles of substrate, season and latitude in shaping intertidal ascomycete community structure were examined for the U.S. Gulf of Mexico, and the role of sampling frequency on species richness estimates was also addressed. Best sampling practices were developed and 750 collections of beach detritus, sand …

Management Of Biological And Chemical Constituents For The Advancement Of Intensive, Minimal-Exchange, Biofloc-Based Shrimp (Litopenaeus Vannamei) Aquaculture, Andrew James Ray

Dissertations

Intensive, minimal-exchange, biofloc-based shrimp aquaculture systems may provide a sustainable alternative to traditional shrimp culture. Through a series of experiments, this document explores the effects of several key management strategies on water quality, isotopic distribution, and shrimp production.

An experiment evaluated the effects of managing suspended solids (biofloc) concentration at two levels. It was found that using a higher flow rate to larger settling chambers resulted in significantly lower biofloc and nitrate concentrations, and significantly improved shrimp growth rate. A second experiment compared systems with clear water and systems with biofloc. The filters in the clear water systems prevented biofloc …

The Role Of The Cysteine/Glutathione Regulatory Genes Cdo1, Gsh1, And Gsh2 In Yeast-Mold Dimorphism Of The Pathogenic Fungus Histoplasma Capsulatum, Melissa Anne Adams

Dissertations

The dimorphism of Histoplasma capsulatum (Hc) from a mold to yeast is regulated by many environmental factors such as temperature and thiol concentrations. Histoplasma exists in the soil (or in vitro at 25ºC) as a multicellular saprophytic mold. In the lungs of an infected host (or in vitro at 37ºC), a shift to the unicellular parasitic yeast occurs. Sulfhydryl groups (-SH), especially cysteine, are necessary in the culture medium for the mold to yeast transition. Cysteine is the precursor for the synthesis of glutathione. Enzymes involved in the cysteine metabolism pathway are being studied in order to evaluate …

Identifying And Characterizing Non-Coding Rnas In The Dinoflagellate Karenia Brevis, Helen Namataka

Master's Theses

When algal cells proliferate and accumulate in marine and fresh water systems, they form algal blo'oms. The majority of these blooms are beneficial, but a significant number are detrimental and are known as harmful algal blooms (HABs). A number of negative effects, including closing of recreational beaches and economic loss, are observed during HABs. Predictably, the longer a bloom persists, the greater its effects on human, environmental and economic health. Karenia brevis, a mixotrophic dinoflagellate, forms HABs, and blooms caused by this organism have been known to remain several months after formation. For these reasons, research has been conducted to …

Fungal Biofilm Colonization And Succession On Artificial Reefs In The North-Central Gulf Of Mexico, Amy Leigh Salamone

Master's Theses

This study represents the first characterization of natural mixed-species fungal biofilm communities on artificial reefs in the marine environment. Previous fungal biofilm studies have failed to observe the naturally-occurring biodiversity in coastal areas, which comprise the most utilized zone of the marine environment. Artificial reefs can increase fishing yields, amplify oyster habitats, contribute to shoreline stabilization, promote good water quality, and deter pollution. Proper management practices of artificial reefs require knowledge of the colonization of these new habitats by marine organisms and their subsequent succession. Fungi, along with bacteria, archaea, protists, algae, and diatoms, quickly form a complex biofilm on …

Several Steps/Day Indicators Predict Changes In Anthropometric Outcomes: Hub City Steps, Jessica L. Thompson, Alicia S. Landry, Jamie M. Zoellner, Catrine Tudor-Locke, Michael Webster, Carol L. Connell, Kathy Yadrick

Faculty Publications

Background: Walking for exercise remains the most frequently reported leisure-time activity, likely because it is simple, inexpensive, and easily incorporated into most people's lifestyle. Pedometers are simple, convenient, and economical tools that can be used to quantify step-determined physical activity. Few studies have attempted to define the direct relationship between dynamic changes in pedometer-determined steps/day and changes in anthropometric and clinical outcomes. Hence, the objective of this secondary analysis was to evaluate the utility of several descriptive indicators of pedometer-determined steps/day for predicting changes in anthropometric and clinical outcomes using data from a community-based walking intervention, HUB City Steps, conducted …

Visual And Electronic Evaluations Of Detached Strawberry Leaves Inoculated With Colletotrichum Species, M. A. Miller-Butler, K. J. Curry, B. R. Kreiser, B. J. Smith

Faculty Publications

Inoculation of detached strawberry leaves with Colletotrichum species may provide an accurate, rapid, non-destructive method of identifying anthracnose resistant germplasm. Two assessments of anthracnose disease severity were compared on detached strawberry leaves inoculated with Colletotrichum fragariae and C. gloeosporioides: a quantitative assessment made via computer-based image analysis and a visual assessment made by two independent raters. The image analysis provided a precise measurement of percent lesion area of infected leaves. There was a strong positive correlation between percent lesion area and the visual disease scores of the raters.

Modeling Photosynthesis Of Spartina Alterniflora (Smooth Cordgrass) Impacted By The Deepwater Horizon Oil Spill Using Bayesian Inference, Wei Wu, Patrick D. Biber, Mark S. Peterson, Chongfeng Gong

Faculty Publications

To study the impact of the Deepwater Horizon oil spill on photosynthesis of coastal salt marsh plants in Mississippi, we developed a hierarchical Bayesian (HB) model based on field measurements collected from July 2010 to November 2011. We sampled three locations in Davis Bayou, Mississippi (30.375 degrees N, 88.790 degrees W) representative of a range of oil spill impacts. Measured photosynthesis was negative (respiration only) at the heavily oiled location in July 2010 only, and rates started to increase by August 2010. Photosynthesis at the medium oiling location was lower than at the control location in July 2010 and it …

Transient Inhibition Of Cell Proliferation Does Not Compromise Self-Renewal Of Mouse Embryonic Stem Cells, Ruoxing Wang, Yan-Lin Guo

Faculty Publications

Embryonic stem cells (ESCs) have unlimited capacity for self-renewal and can differentiate into various cell types when induced. They also have an unusual cell cycle control mechanism driven by constitutively active cyclin dependent kinases (Cdks). In mouse ESCs (mESCs). It is proposed that the rapid cell proliferation could be a necessary part of mechanisms that maintain mESC self-renewal and pluripotency, but this hypothesis is not in line with the finding in human ESCs (hESCs) that the length of the cell cycle is similar to differentiated cells. Therefore, whether rapid cell proliferation is essential for the maintenance of mESC state remains …

Nutrient Depletion As A Proxy For Microbial Growth In Deepwater Horizon Subsurface Oil/Gas Plumes, Alan M. Shiller, Dongjoo Joung

Faculty Publications

The Deepwater Horizon accident resulted in a substantial uncontrolled hydrocarbon release to the northern Gulf of Mexico, much of which was entrained in deep submerged plumes. While bio-degradation of the hydrocarbons has been inferred from microbial biomass and genetics, the amount of conversion of oil and gas carbon to biomass remains uncertain having only been estimated in modeling studies. Here we examine correlated depletions of nitrate, phosphate and oxygen in the submerged plumes and conclude that a substantial portion of hydrocarbons in these plumes was converted to biomass (0.8-2 x 10(10) mol C). This contrasts with nutrient-limited surface waters where …

Ecology Of Vibrio Parahaemolyticus And Vibrio Vulnificus In The Coastal And Estuarine Waters Of Louisiana, Maryland, Mississippi, And Washington (United States), Crystal N. Johnson, John C. Bowers, Kimberly J. Griffitt, Vanessa Molina, Rachel W. Clostio, Shaofeng Pei, Edward Laws, Rohinee N. Paranjpye, Mark S. Strom, Arlene Chen, Nur A. Hasan, Anwar Huq, Nicholas F. Noriea Iii, D. Jay Grimes, Rita R. Colwell

Faculty Publications

Vibrio parahaemolyticus and Vibrio vulnificus, which are native to estuaries globally, are agents of seafood-borne or wound infections, both potentially fatal. Like all vibrios autochthonous to coastal regions, their abundance varies with changes in environmental parameters. Sea surface temperature (SST), sea surface height (SSH), and chlorophyll have been shown to be predictors of zooplankton and thus factors linked to vibrio populations. The contribution of salinity, conductivity, turbidity, and dissolved organic carbon to the incidence and distribution of Vibrio spp. has also been reported. Here, a multicoastal, 21-month study was conducted to determine relationships between environmental parameters and V. parahaemolyticus …

A New Us Polar Research Vessel For The Twenty-First Century, Robert B. Dunbar, Jon Alberts, Carin Ashjian, Vernon Asper, Dale Chayes, Eugene Domack, Hugh Ducklow, Bruce Huber, Lawrence Lawver, Daniel Oliver, Doug Russell, Craig R. Smith, Maria Vernet

Faculty Publications

Scientific and political interests at the poles are significant and rapidly increasing, driven in part by the effects of climate change and emerging geopolitical realities. The polar regions provide important services to global ecosystems and humankind, ranging from food and energy to freshwater and biodiversity. Yet the poles are experiencing changes at rates that far outpace the rest of the planet. Coastal Arctic communities are impacted by climate change through coastal erosion, sea level rise, ice loss, and altered marine food webs, threatening the future of their subsistence lifestyle. Climate change has dramatically increased the melt rate of ice sheets …

A Novel Allosteric Inhibitor Of Macrophage Migration Inhibitory Factor (Mif), Fengwei Bai, Oluwatoyin A. Asojo, Pier Cirillo, Mihai Ciustea, Michel Ledzidet, Paul A. Aristoff, Lin Leng, Raymond A. Koski, Thomas J. Powell, Richard Bucala, Karen G. Anthony

Faculty Publications

Macrophage migration inhibitory factor (MIF) is a catalytic cytokine and an upstream mediator of the inflammatory pathway. MIF has broad regulatory properties, dysregulation of which has been implicated in the pathology of multiple immunological diseases. Inhibition of MIF activity with small molecules has proven beneficial in a number of disease models. Known small molecule MIF inhibitors typically bind in the tautomerase site of the MIF trimer, often covalently modifying the catalytic proline. Allosteric MIF inhibitors, particularly those that associate with the protein by noncovalent interactions, could reveal novel ways to block MIF activity for therapeutic benefit and serve as chemical …

Immunostimulatory And Cellular Toxic Effects Of Single-Stranded Rna On Cancer Cells, Chengwen Teng

Master's Theses

Whether 5'-triphosphate-single-stranded-RNA (5 '-ppp-ssRNA) is immunostimulatory was controversial in the literature. In order to clarify the immunostimulatory effect of 5'-ppp-ssRNA, we synthesized ssRNAs and tested the IFNp (interferon-beta) level and cellular toxicity of ssRNAs in SKOV3 cells. In this work, we confirmed that 5'-ppp-ssRNA (~ 60nt) was immunostimulatory and toxic in SKOV3 cells. 5'-ppp-ssRNA (~ 60nt) led to IFN-P induction and apoptosis in SKOV3 cells. Longer 5' ppp- ssRNA tended to have a higher immunostimulatory effect and cellular toxicity than shorter 5'-ppp-ssRNA. 5'-ppp-ssRNA was more immunostimulatory and toxic than 5'- 0H-ssRNA. If the incubation time of ssRNAs increased, the toxicity …

Il-22 Signaling Contributes To West Nile Encephalitis Pathogenesis, Fengwei Bai, Penghua Wang, Lauren A. Zenewicz, Jianfeng Dai, David Gate, Gong Cheng, Long Yang, Feng Qian, Xiaoling Yuan, Ruth R. Montgomery, Richard A. Flavell, Terrence Town, Erol Fikrig

Faculty Publications

The Th17 cytokine, IL-22, regulates host immune responses to extracellular pathogens. Whether IL-22 plays a role in viral infection, however, is poorly understood. We report here that Il22^-/- mice were more resistant to lethal West Nile virus (WNV) encephalitis, but had similar viral loads in the periphery compared to wild type (WT) mice. Viral loads, leukocyte infiltrates, proinflammatory cytokines and apoptotic cells in the central nervous system (CNS) of Il22^-/- mice were also strikingly reduced. Further examination showed that Cxcr2, a chemokine receptor that plays a non-redundant role in mediating neutrophil migration, was significantly reduced in Il22^{-/- …}

Effects Of Hurricane Disturbance On The Stopover Ecology Of Intercontinental Landbird Migrants In Coastal Louisiana, Emily Johanna Lain

Master's Theses

Few studies have considered the impact of weather events on migratory birds during stopover, and essentially none on how hurricanes affect their stopover biology during spring passage. About two thirds of eastern North American forest breeding bird species migrate twice annually between temperate breeding areas and subtropical and tropical wintering grounds, and movement in relation to the Gulf of Mexico (GOM) is a conspicuous and important part of that migration system. During inclement weather or winds inconsistent with travel direction, migratory birds oft.en/a/lout and concentrate by the thousands in forest patches that occur along the northern coast of the GOM. …

Phase Speciation Of Carbohydrates And Dioxins In Rivers And Coastal Waters In The Northern Gulf Of Mexico, Kusumica Mitra

Master's Theses

Dissolved carbohydrates (d-CHO), including monosaccharide (MCHO) and polysaccharides (PCHO), and particulate carbohydrates (p-CHO) are major components of natural organic matter and play an important role in biogeochemical cycles of carbon and other trace elements in marine environments. This study aimed to examine the abundance and partitioning of CHO between dissolved and particulate phases and their seasonal variations in the Mississippi Sound/Bight and Lake Pontchartrain. Laboratory mixing experiments were also carried out to examine the behaviour of CHO species along a salinity gradient. The phase partitioning of dioxin among three different phases, i.e., colloidal organic matter, particulate organic matter and sediments, …

Determining The Trophic Role Of Gulf Menhaden (Brevoortia Patronus) Using Carbon And Nitrogen Stable Isotopes, Zachary Olsen

Master's Theses

Gulf menhaden (Brevoortia patronus) play multiple roles in the Gulf of Mexico coastal ecosystem as filter feeders and as an important food source for many recreationally and economically important finfish. Gulf menhaden also support a large commercial fishery, and little is known about the impact of fishing on the role of this species as a filter feeder in the food web. This study examines the spatial, temporal and ontogenetic dynamics of food selectivity and trophic role observed in Gulf menhaden. The most important dietary item for juvenile fish was found to be phytoplankton (75.7% dietary composition) while that of subadults …

Anode Material Testing For Marine Sediment Microbial Fuel Cells, Andrew John Quaid

Master's Theses

Research on the power production of the microbial fuel cell has increased in the past decade. The sediment microbial fuel cell is a type of fuel cell that uses the environment of submerged sediments to provide a natural voltage difference. The fuel cell is comprised of an anode buried in the sediment and a cathode that is held in the overlying water column. The process of electron transfer to the anode is catalyzed by anaerobic bacteria in the sediment. The anaerobic bacteria have that are able to catalyze the electron transfer have been termed exoelectrogenic. The increase in scientific research …

Evaluating Macrobenthic Indicators Of Organic Enrichment And Hypoxia Within The Coastal Mississippi Hypoxic Zone, Daneen P. Menke

Master's Theses

Macrobenthic communities offer effective indicators of biotic integrity, but their use for distinguishing anthropogenic from natural stress is tricky because coastal taxa are eurytolerant. Effective coastal management calls for benthic indicators that respond to specific stressors, apply across different habitats, and reflect ecosystem function. Macrobenthic process metrics based on body-size descriptors should reflect ecosystem function and be useful for assessing the effects of eutrophication. Functional trait analysis should reflect the functional diversity of the community. Coastal Mississippi experienced widespread and sustained hypoxia throughout summer 2008. Site 6 located on the 10-m isobath in the center of the 2008 hypoxic zone …

Experimental Evidence For The Interplay Of Exogenous And Endogenous Factors On The Movement Ecology Of A Migrating Songbird, Emily B. Cohen, Frank R. Moore, Richard A. Fischer

Faculty Publications

Movement patterns during songbird migration remain poorly understood despite their expected fitness consequences in terms of survival, energetic condition and timing of migration that will carry over to subsequent phases of the annual cycle. We took an experimental approach to test hypotheses regarding the influence of habitat, energetic condition, time of season and sex on the hour-by-hour, local movement decisions of a songbird during spring stopover. To simulate arrival of nocturnal migrants at unfamiliar stopover sites, we translocated and continuously tracked migratory red-eyed vireos (Vireo olivaceus) throughout spring stopover with and without energetic reserves that were released in two replicates …

Evolution Of A Sexually Dimorphic Trait In A Broadly Distributed Topminnow (Fundulus Olivaceus), Jacob F. Schaefer, David D. Duvernell, Brian R. Kreiser, Charles Champagne, Scott R. Clark, Melissa Gutierrez, Laura K. Stewart, Chazz Coleman

Faculty Publications

Understanding the interaction between sexual and natural selection within variable environments is crucial to our understanding of evolutionary processes. The handicap principle predicts females will prefer males with exaggerated traits provided those traits are indicators of male quality to ensure direct or indirect female benefits. Spatial variability in ecological factors is expected to alter the balance between sexual and natural selection that defines the evolution of such traits. Male and female blackspotted topminnows (Fundulidae: Fundulus olivaceus) display prominent black dorsolateral spots that are variable in number across its broad range. We investigated variability in spot phenotypes at 117 sites …

Impacts Of Upstream Drought And Water Withdrawals On The Health And Survival Of Downstream Estuarine Oyster Populations, Laura E. Petes, Alicia J. Brown, Carley R. Knight

Faculty Publications

Increases in the frequency, duration, and severity of regional drought pose major threats to the health and integrity of downstream ecosystems. During 2007-2008, the U.S. southeast experienced one of the most severe droughts on record. Drought and water withdrawals in the upstream watershed led to decreased freshwater input to Apalachicola Bay, Florida, an estuary that is home to a diversity of commercially and ecologically important organisms. This study applied a combination of laboratory experiments and field observations to investigate the effects of reduced freshwater input on Apalachicola oysters. Oysters suffered significant disease-related mortality under high-salinity, drought conditions, particularly during the …

Were Multiple Stressors A "Perfect Storm" For Northern Gulf Of Mexico Bottlenose Dolphins (Tursiops Truncatus) In 2011?, Ruth H. Carmichael, William M. Graham, Allen Aven, Graham Worthy, Stephan D. Howden

Faculty Publications

An unusual number of near term and neonatal bottlenose dolphin (Tursiops truncatus) mortalities occurred in the northern Gulf of Mexico (nGOM) in 2011, during the first calving season after two well documented environmental perturbations; sustained cold weather in 2010 and the Deepwater Horizon oil spill (DWHOS). Preceding the stranding event, large volumes of cold freshwater entered the nGOM due to unusually large snowmelt on the adjacent watershed, providing a third potential stressor. We consider the possibility that this extreme cold and freshwater event contributed to the pattern of perinatal dolphin strandings along the nGOM coast. During the 4-month period starting …

Survival, Growth And Reproduction Of Non-Native Nile Tilapia Ii: Fundamental Niche Projections And Invasion Potential In The Northern Gulf Of Mexico, Michael R. Lowe, Wei Wu, Mark S. Peterson, Nancy J. Brown-Peterson, William T. Slack, Pamela J. Schofield

Faculty Publications

Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity …

Concurrent Effects Of Resource Pulse Amount, Type, And Frequency On Community And Population Properties Of Consumers In Detritus-Based Systems, Donald A. Yee, Steven A. Juliano

Faculty Publications

Episodic resource inputs (i.e., pulses) can affect food web properties and community dynamics, but detailed mechanistic understanding of such effects remain elusive. Natural aquatic microsystems (e.g., tree holes, human-made containers) are colonized by invertebrates that form complex food webs dependent on episodic and sometimes sizeable inputs of allochthonous detritus from adjacent terrestrial environments. We investigated how variation in pulse frequency, amount, and resource type interacted to affect richness, abundance, composition, and population sizes of colonizing invertebrates in water-filled tires and tree hole analogs in a forest habitat. Different container types were used to assess the generality of effects across two …