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Articles 601 - 630 of 1123

Full-Text Articles in Ecology and Evolutionary Biology

Are Circadian Cycles The Dominant Proteome Rhythym In The Intertidal Mussel Mytilus Californianus?, Kristina M. Koster, Cory Elowe, Lars Tomanek Jan 2015

Are Circadian Cycles The Dominant Proteome Rhythym In The Intertidal Mussel Mytilus Californianus?, Kristina M. Koster, Cory Elowe, Lars Tomanek

STAR Program Research Presentations

Mytilus californianus, also known as the California mussel, is a marine bivalve that is abundant along the West coast from Alaska to southern Baja California. They mainly reside in the upper-middle intertidal zone and cling to pier pilings and surf exposed rocks. They create multi-layered beds, which form a habitat for algae and many species of invertebrates. Intertidal mussels live in a naturally dynamic environment. It has previously been reported (Connor and Gracey, 2011) that the 24-hour circadian (day to night) rhythm of the intertidal mussel Mytilus californianus is primarily responsible for its rhythmic gene expression, as opposed to …


Sea Turtle Hatchling Sex Ratios Determined Via Hormone Assay: Implications Of Climate Change?, William A. Hilton, Matthew Godfrey, Camryn D. Allen Jan 2015

Sea Turtle Hatchling Sex Ratios Determined Via Hormone Assay: Implications Of Climate Change?, William A. Hilton, Matthew Godfrey, Camryn D. Allen

STAR Program Research Presentations

Currently all species of sea turtles are listed as threatened or endangered with extinction under the U.S. Endangered Species Act. Due to their status, sea turtle conservation is a high priority for the U.S. National Marine Fisheries Service and U.S. Fish and Wildlife Service. One major challenge conservationists face is the lack of a noninvasive, cost efficient method for determining the sex of hatchling sea turtles. Because secondary sex characteristics (i.e. males have longer tails) are not evident until turtles start to reach sexual maturity, the sex of hatchlings is not easily determined. The least invasive way to determine the …


Further Description Of Hybridization In The Sea Stars Asterias Rubens And Asterias Forbesi Through The Application Of Species-Specific Genetic Markers, Callie Bateson Jan 2015

Further Description Of Hybridization In The Sea Stars Asterias Rubens And Asterias Forbesi Through The Application Of Species-Specific Genetic Markers, Callie Bateson

Honors Program Theses

Hybridization occurs when two separate species reproduce to form hybrid offspring. If the hybrid offspring backcross with individuals of their parental species, the subsequent offspring may have varying amounts of the parental genomes, if viable. Following the retreat of the Last Glacial Maxima 20,000 years ago, two sea star species, Asterias forbesi and A. rubens came into secondary contact in the Gulf of Maine where they began to hybridize. Previous research in our lab studied the frequency of hybridization at four locations along the east coast (Quebec, Nova Scotia, New Hampshire, and New York) using morphological identifications as well two …


Quantifying Florida Bay Habitat Suitability For Fishes And Invertebrates Under Climate Change Scenarios, Kelly A. Kearney, Mark J. Butler Iv, Robert Glazer, Christopner R. Kelble, Joseph E. Serafy, Erik Stabenau Jan 2015

Quantifying Florida Bay Habitat Suitability For Fishes And Invertebrates Under Climate Change Scenarios, Kelly A. Kearney, Mark J. Butler Iv, Robert Glazer, Christopner R. Kelble, Joseph E. Serafy, Erik Stabenau

Biological Sciences Faculty Publications

The Florida Bay ecosystem supports a number of economically important ecosystem services, including several recreational fisheries, which may be affected by changing salinity and temperature due toclimate change. In this paper, we use a combination of physical models and habitat suitability index models to quantify the effects of potential climate change scenarios on a variety of juvenile fish and lobster species in Florida Bay. The climate scenarios include alterations in sea level, evaporation and precipitation rates, coastal runoff, and water temperature. We find that the changes in habitat suitability vary in both magnitude and direction across the scenarios and species, …


Behavioral Response Of Pacific Lamprey (Entosphenus Tridentatus) To Predator Odors, Laurie L. Porter Jan 2015

Behavioral Response Of Pacific Lamprey (Entosphenus Tridentatus) To Predator Odors, Laurie L. Porter

All Master's Theses

Pacific lamprey (Entosphenus tridentatus), a species facing serious threats to their existence, experience a number of challenges in reaching their desired spawning grounds during the adult migratory phase, and predators are suspected to be one of these challenges. Understanding if Pacific lamprey respond to predator odorants may provide a management tool for use in conjunction with attractants in guiding lamprey to suitable spawning habitat and deterring them from poor habitat. Previous research has failed to explore Pacific lamprey response to predator odorants, although much research exists on attractant odorants. In our study, we tested Pacific lamprey response to …


Horseshoe Crab Research In Urban Estuaries: Challenges And Opportunities, Jennifer Mattei, Mark L. Botton, Mark Beekey, Christina P. ColóN Jan 2015

Horseshoe Crab Research In Urban Estuaries: Challenges And Opportunities, Jennifer Mattei, Mark L. Botton, Mark Beekey, Christina P. ColóN

Biology Faculty Publications

Horseshoe crabs rely on estuaries for food resources, places to spawn and for larvae and juveniles to develop and grow. Many of these estuaries are becoming increasingly urbanized and dominated by human activity. An urban estuary is characterized by armored shorelines, high nutrient loads, large fluctuations in algal and bacteria populations, increased levels of pollutants like heavy metals and pesticides, and seasonally low oxygen levels and pH. While urban estuaries are challenging for horseshoe crab survival and to researchers trying to study them, there are also opportunities for involving the public in research and increasing public awareness of the importance …


The Mismanagement Of Limulus Polyphemus In Long Island Sound, U.S.A.: What Are The Characteristics Of A Population In Decline?, Mark Beekey, Jennifer Mattei Jan 2015

The Mismanagement Of Limulus Polyphemus In Long Island Sound, U.S.A.: What Are The Characteristics Of A Population In Decline?, Mark Beekey, Jennifer Mattei

Biology Faculty Publications

Over the past 15 years, horseshoe crabs in Connecticut have gone from being considered a nuisance species to a species of Greatest Conservation Need in 2015. This has happened through first, its discovery as an economically important species, second through research of its ecological role in coastal estuaries, and third, through education of the public concerning its role in the environment and their own health. To manage horseshoe crab populations successfully requires long term monitoring, research and education. The use of annual or biannual trawl data trends to assess the success of management decisions is limited due to the high …


New Tracer To Estimate Community Predation Rates Of Phagotrophic Protists, Alexander B. Bochdansky, Melissa A. Clouse Jan 2015

New Tracer To Estimate Community Predation Rates Of Phagotrophic Protists, Alexander B. Bochdansky, Melissa A. Clouse

OES Faculty Publications

Predation of eukaryotic microbes on prokaryotes is one of the most important trophic interactions on Earth, representing a major mortality term and shaping morphology and composition of prokaryotic communities. Here we introduce and validate a new tracer to determine predation rates on prokaryotes. Minicells of Escherichia coli marked with a bright green fluorescent protein (GFP) vector have many operational advantages over previously used prey analogs such as fluorescently labeled bacteria. GFP-minicells are similar in size to naturally occurring bacteria from a variety of environments including the oligotrophic open ocean and the deep sea. They are relatively stable against microbial and …


The Role Of Citizens In Detecting And Responding To A Rapid Marine Invasion, Steven B. Scyphers, Sean P. Powers, J. Lad Akins, J. Marcus Drymon, Charles W. Martin, Zeb H. Schobernd, Pamela J. Schofield, Robert L. Shipp, Theodore S. Switzer Jan 2015

The Role Of Citizens In Detecting And Responding To A Rapid Marine Invasion, Steven B. Scyphers, Sean P. Powers, J. Lad Akins, J. Marcus Drymon, Charles W. Martin, Zeb H. Schobernd, Pamela J. Schofield, Robert L. Shipp, Theodore S. Switzer

University Faculty and Staff Publications

Documenting and responding to species invasions requires innovative strategies that account for ecological and societal complexities. We used the recent expansion of Indo-Pacific lionfish (Pterois volitans/miles) throughout northern Gulf of Mexico coastal waters to evaluate the role of stakeholders in documenting and responding to a rapid marine invasion. We coupled an online survey of spearfishers and citizen science monitoring programs with traditional fishery-independent data sources and found that citizen observations documented lionfish 1–2 years earlier and more frequently than traditional reef fish monitoring programs. Citizen observations first documented lionfish in 2010 followed by rapid expansion and proliferation in …


Iron Deficiency Increases Growth And Nitrogen-Fixation Rates Of Phosphorus-Deficient Marine Cyanobacteria, Nathan S. Garcia, Feixue Fu, Peter N. Sedwick, David A. Hutchins Jan 2015

Iron Deficiency Increases Growth And Nitrogen-Fixation Rates Of Phosphorus-Deficient Marine Cyanobacteria, Nathan S. Garcia, Feixue Fu, Peter N. Sedwick, David A. Hutchins

OES Faculty Publications

Marine dinitrogen (N2)-fixing cyanobacteria have large impacts on global biogeochemistry as they fix carbon dioxide (CO2) and fertilize oligotrophic ocean waters with new nitrogen. Iron (Fe) and phosphorus (P) are the two most important limiting nutrients for marine biological N2 fixation, and their availabilities vary between major ocean basins and regions. A long-standing question concerns the ability of two globally dominant N2-fixing cyanobacteria, unicellular Crocosphaera and filamentous Trichodesmium, to maintain relatively high N2-fixation rates in these regimes where both Fe and P are typically scarce. We show that under P-deficient …


Habitat Value Of Restored Intertidal Shoreline For Fish And Macrobenthic Communities In Northeast Florida, Shannon K. Dunnigan Jan 2015

Habitat Value Of Restored Intertidal Shoreline For Fish And Macrobenthic Communities In Northeast Florida, Shannon K. Dunnigan

UNF Graduate Theses and Dissertations

Oyster reefs are declining worldwide, as well as the economic and ecological value of oysters to their respective systems. Numerous restoration efforts have been undertaken in hopes of re-establishing these shellfish populations. This study evaluated a restoration project within the Guana Tolomato Matanzas estuary in northeast Florida, U.S.A., to investigate community structure as well as seasonal patterns in species abundance and diversity of juvenile fish and benthic macrofauna within restored and unrestored intertidal habitats along the Guana Peninsula. The first objective was to determine whether the artificially created reefs provided similar quantity and diversity of benthic macrofauna as adjacent unrestored …


Fisheries Management Paper No.266 - Exmouth Gulf Prawn Managed Fishery Bycatch Action Plan 2014-2019. Version 1.0, Department Of Fisheries, Western Australia Nov 2014

Fisheries Management Paper No.266 - Exmouth Gulf Prawn Managed Fishery Bycatch Action Plan 2014-2019. Version 1.0, Department Of Fisheries, Western Australia

Fisheries Management Papers

Bycatch is described as the part of the catch which is returned to the sea (usually referred to as non-retained or discarded) either because it has no commercial value or because legislative requirements preclude it being retained. Thus, this Bycatch Action Plan (BAP) includes unmarketable finfish and invertebrate species, along with endangered, threatened and protected (ETP) species, such as marine mammals, reptiles and some elasmobranchs.

It is Government policy to minimise bycatch in all commercial fisheries. This BAP details a program of actions to address bycatch issues in the Exmouth Gulf Prawn Managed Fishery (EGPMF), in accordance with the EGPMF …


Fisheries Management Paper No.265 - Exmouth Gulf Prawn Managed Fishery Harvest Strategy 2014 - 2019 Version 1.0, Department Of Fisheries Western Australia Nov 2014

Fisheries Management Paper No.265 - Exmouth Gulf Prawn Managed Fishery Harvest Strategy 2014 - 2019 Version 1.0, Department Of Fisheries Western Australia

Fisheries Management Papers

This fishery-specific harvest strategy has been developed in line with the Department of Fisheries' (Department) over-arching Harvest Strategy Policy for Aquatic Resources (Department of Fisheries in prep.) and in consultation with licensees. The broad scope of the Harvest Strategy Policy for Aquatic Resources is consistent with the National Harvest Strategy Guidelines but as well as considering all retained target species, it also incorporates retained non-target species, bycatch' and other ecological components to ensure the risks to these elements are managed effectively.

The Exmouth Gulf Prawn Managed Fishery (EGPMF) harvest strategy outlines the longand short-term fishery-specific management objectives; a description of …


The Status Of Fishes In The Missouri River, Nebraska: Lake Sturgeon (Acipenser Fulvescens), Kirk D. Steffensen, Sam Stukel, Dane A. Shuman Oct 2014

The Status Of Fishes In The Missouri River, Nebraska: Lake Sturgeon (Acipenser Fulvescens), Kirk D. Steffensen, Sam Stukel, Dane A. Shuman

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Lake Sturgeon (Acipenser fulvescens) occurrences in the Missouri River along Nebraska’s eastern border are historically sporadic and rare. Presently, the wild Lake Sturgeon population in this river reach may be extirpated. A Recovery Program initiated by the Missouri Department of Conservation (MDC) has stocked almost 150,000 hatchery-reared Lake Sturgeon into the lower Missouri River at several sites in Missouri. As a result, the number of Lake Sturgeon collected has increased. Since monitoring began in 2003, no Lake Sturgeon have been collected above Gavins Point Dam while 40 fish were collected downstream of Gavins Point Dam. The majority of …


Nitrogen, Phosphorus, And Suspended Solids Concentrations In Tributaries To The Great Bay Estuary Watershed In 2014, Matthew A. Wood Oct 2014

Nitrogen, Phosphorus, And Suspended Solids Concentrations In Tributaries To The Great Bay Estuary Watershed In 2014, Matthew A. Wood

PREP Reports & Publications

Nitrogen, phosphorus, and sediment loads to the Great Bay Estuary are a constant concern. The Piscataqua Region Estuaries Partnership (PREP) calculates the nitrogen load from tributaries to the Great Bay Estuary for its State of Our Estuaries reports. Therefore, the purpose of this study was to collect representative data on nitrogen, phosphorus, and suspended sediment concentrations in tributaries to the Great Bay Estuary in 2014. The study design followed the tributary sampling design which was implemented by the New Hampshire Department of Environmental Services between 2001 and 2007 and sustained by the University of New Hampshire from 2008 to the …


Estimating Migration Rates Between Populations Of Zostera Marina In The San Francisco Bay, Elizabeth S. Gutierrez Sep 2014

Estimating Migration Rates Between Populations Of Zostera Marina In The San Francisco Bay, Elizabeth S. Gutierrez

STAR Program Research Presentations

Eelgrass (Zostera marina) is a highly clonal marine angiosperm that can also reproduce sexually through flowering and seed formation. In a previous study, Fst values from six microsatellite loci suggested that a perennial San Francisco Bay subpopulation at Point Molate (Richmond, California) was able to recover from a drastic 2006 die-off through seed recruitment from neighboring eelgrass subpopulations, changing its reproductive strategy from clonal to sexual. Although Fst measures continue to be widely used in population genetics, the assumptions under which they operate are not always appropriate given certain circumstances, such small population sizes and/or asymmetrical migration rates. Our summer …


Jellyfish Throwdown: Invasive Versus Native, Brooke Bemowski, Trisha Huynh, Lindsay J. Sullivan, Wim Kimmerer Aug 2014

Jellyfish Throwdown: Invasive Versus Native, Brooke Bemowski, Trisha Huynh, Lindsay J. Sullivan, Wim Kimmerer

STAR Program Research Presentations

The San Francisco Bay Estuary is home to many species of marine and wildlife that create a delicate ecological balance. Invasive jellyfish introduced to the bay though cargo shipping are believed to be competing with the endangered delta smelt for the same food source of copepods. Samples of zooplankton were taken from high and low salinity zones in the San Francisco Bay over three years in months June through February to correlate with the peak of the jellyfish lifecycle. The preserved samples are looked through and jellyfish are removed and recorded. The species of jellyfish is determined using features such …


The Path To The Sea: Leatherback Hatchling Orientation At Sandy Point National Wildlife Refuge, Christina Macmillan, Kelly Stewart Aug 2014

The Path To The Sea: Leatherback Hatchling Orientation At Sandy Point National Wildlife Refuge, Christina Macmillan, Kelly Stewart

STAR Program Research Presentations

Once sea turtle hatchlings emerge from their nest, they must find their way to the ocean by using cues such as a bright horizon and the slope of the beach. While moving toward the water, hatchlings often must navigate past predators and through vegetation, sticks, footprints in the sand, and other dangers such as ghost crab holes. Sometimes hatchlings become confused (or disoriented) and turn in circles to find the right route to the water. Sea turtle hatchlings also may become disoriented as a result of human impacts such as town lights or trash. The purpose of our experiment was …


Salinity Distribution Of Microplankton In The San Francisco Estuary, Carrie Ann Sharitt, Lindsay Sullivan, Wim Kimmerer Aug 2014

Salinity Distribution Of Microplankton In The San Francisco Estuary, Carrie Ann Sharitt, Lindsay Sullivan, Wim Kimmerer

STAR Program Research Presentations

Microplankton are a diverse group of planktonic organisms ranging from 0.02 to 0.2 millimeters. Since the group is defined solely by size, it spans numerous taxonomic groups, including both heterotrophs and autotrophs. Microplankton are abundant in all aquatic ecosystems and are important prey for many organisms, including bivalves, crustaceans, and fish. The San Francisco Bay is truly an estuary as saltwater enters the estuary under the Golden Gate Bridge and freshwater flows in from the Sacramento and San Joaquin Rivers. Thus, there is a gradient of salinity from freshwater (0) in the rivers to saltwater by the Golden Gate Bridge …


The Ecological Impact Of Casitas On Caribbean Spiny Lobster (Panulirus Argus) Populations In The Florida Keys, Fl, (Usa), Benjamin C. Gutzler Jul 2014

The Ecological Impact Of Casitas On Caribbean Spiny Lobster (Panulirus Argus) Populations In The Florida Keys, Fl, (Usa), Benjamin C. Gutzler

Biological Sciences Theses & Dissertations

Casitas are artificial structures placed on the seabed by fishermen to aggregate Caribbean spiny lobsters (Panulirus argus) for ease of capture. Some researchers suggest that they may also enhance lobster populations in shelter-limited environments. Conversely, aggregation of lobsters within casitas may be detrimental to the population if the nutritional condition or mortality of lobsters is poorer in casitas than in natural shelters. Small juvenile lobsters may be at particular risk because their foraging range is smaller and they are more readily preyed upon than larger lobsters. If so, then casitas placed in lobster nurseries may function as "ecological traps"; wherein …


Factors In Long-Term Algal Composition Of Cayman Reefs: Determining Effects Of Natural Disturbance And Grazer Pressures, Patrick J. Doughty Jun 2014

Factors In Long-Term Algal Composition Of Cayman Reefs: Determining Effects Of Natural Disturbance And Grazer Pressures, Patrick J. Doughty

Lawrence University Honors Projects

Abstract. Current research shows a worldwide shift in the population dynamics of reefs attributed to increasing human disturbance. With increasing nutrient additions, competitive populations of turf and macroalgae bloom and dominate coral reefs leading to decreased health of the reef as a whole. Unfortunately, few studies have been done showing the long-term changes in algae composition on reefs. In order to find the significant factors in the long-term composition of algae on reefs, algae and fish abundance data were collected through the Lawrence University Marine Program and analyzed for this study. Algae were split into three functional groups: encrusting, turf …


Coral-Fish Dynamics And Interactions: A Case Study Of Grand Cayman, Eileen Shea Davis Jun 2014

Coral-Fish Dynamics And Interactions: A Case Study Of Grand Cayman, Eileen Shea Davis

Lawrence University Honors Projects

To better understand the ecological interactions of coral reefs, it is important to understand the mechanisms that control the distribution and abundance of reef-building corals as well as the mechanisms that control the diversity and abundance of the fish community that inhabits these reef habitats. The purpose of this study was to identify specific coral-fish interactions among the reefs of Grand Cayman in order to gain insight into the biological effects of fish on the assemblage of hard corals. Using data collected by the Lawrence University Marine Program (LUMP), a number of exploratory statistical analyses were run in order to …


Evidence Of Climate-Induced Range Contractions In Bull Trout Salvelinus Confluentus In A Rocky Mountain Watersehd, U.S.A., Lisa A. Eby, Olga E. Helmy, Lisa M. Holsinger, Michael K. Young Jun 2014

Evidence Of Climate-Induced Range Contractions In Bull Trout Salvelinus Confluentus In A Rocky Mountain Watersehd, U.S.A., Lisa A. Eby, Olga E. Helmy, Lisa M. Holsinger, Michael K. Young

Wildlife Biology Faculty Publications

Many freshwater fish species are considered vulnerable to stream temperature warming associated with climate change because they are ectothermic, yet there are surprisingly few studies documenting changes in distributions. Streams and rivers in the U.S. Rocky Mountains have been warming for several decades. At the same time these systems have been experiencing an increase in the severity and frequency of wildfires, which often results in habitat changes including increased water temperatures. We resampled 74 sites across a Rocky Mountain watershed 17 to 20 years after initial samples to determine whether there were trends in bull trout occurrence associated with temperature, …


Distribution And Dynamic Habitat Use Of Young Bull Sharks Carcharhinus Leucas In A Highly Stratified Northern Gulf Of Mexico Estuary, J. Marcus Drymon, Matthew J. Ajemian, Sean P. Powers May 2014

Distribution And Dynamic Habitat Use Of Young Bull Sharks Carcharhinus Leucas In A Highly Stratified Northern Gulf Of Mexico Estuary, J. Marcus Drymon, Matthew J. Ajemian, Sean P. Powers

University Faculty and Staff Publications

Understanding how animals alter habitat use in response to changing abiotic conditions is important for effective conservation management. For bull sharks (Carcharhinus leucas), habitat use has been widely examined in the eastern and western Gulf of Mexico; however, knowledge of their movements and the factors influencing them is lacking for populations in the more temperate north-central Gulf of Mexico. To examine how changes in hydrographic conditions affected the presence of young bull sharks in Mobile Bay, Alabama, thirty-five sharks were fitted with internal acoustic transmitters and monitored with an acoustic monitoring array consisting of thirty-three receivers between June …


Use Of Coastal Islands By Seabirds: A Tool To Guide Future Marine Protected Areas In California, Dana A. Page May 2014

Use Of Coastal Islands By Seabirds: A Tool To Guide Future Marine Protected Areas In California, Dana A. Page

Master's Projects and Capstones

Seabird breeding colonies on islands off the coast of California offer a unique tool to help guide marine spatial planning. The life histories of seabirds can be used to develop locations of ecological importance along the coast of California. Tracking methodologies and habitat modeling related to seabird habitat utilization can be used to inform management approaches which can aid in the expansion of marine protected areas (MPAs). Protecting ocean habitats will help mitigate impacts of climate change and ensure the ecosystem services provided by marine environments. Areas within the Monterey Bay National Marine Sanctuary were analyzed to locate candidate MPA …


Water Water Everywhere: Analyzing Long Island's Water Issues And Finding Solutions For A Sustainable Future, Anthony T. Becker May 2014

Water Water Everywhere: Analyzing Long Island's Water Issues And Finding Solutions For A Sustainable Future, Anthony T. Becker

2014 Student Theses

Over three million people call Long Island their home. With access to beautiful landscapes, world-renowned beaches, and proximity to New York City, it is no wonder that so many proudly call this geographic stretch of glacial till their home. However, throughout the years our actions do not necessarily reflect this affection we have to our home. Years of sprawl and human infestation across the island have resulted in widespread environmental degradation. Specifically, the water we drink and the beaches we enjoy have become endangered. I plan on studying the urban ecology of how intensified population growth led to the eutrophication …


Elements Of A Successful Plan: Marine Invasive Species Management, Caitlin Gerber May 2014

Elements Of A Successful Plan: Marine Invasive Species Management, Caitlin Gerber

Muskie School Capstones and Dissertations

Marine invasive species are becoming an increasing threat to marine ecosystems and coastal economies around the world. The purpose of this study is to determine the elements of an effective invasive species program in a variety of places and to come up with suggestions for how to implement this in Maine, specifically in terms of combatting Green Crabs


Response Of Large River Fishes To A Prolonged High Water Event In The Missouri River, Nebraska, Nicholas Paul Hogberg May 2014

Response Of Large River Fishes To A Prolonged High Water Event In The Missouri River, Nebraska, Nicholas Paul Hogberg

School of Natural Resources: Dissertations, Theses, and Student Research

Regulation and modification of large rivers to accommodate human uses have been a root cause of freshwater biodiversity declines. The Missouri River is among the most drastically-altered large river systems in North America, with a series of mainstem impoundments in the upper watershed altering flow characteristics downstream, and channelization throughout the lower river homogenizing instream habitat and reducing off-channel habitat. Precipitation events during the winter and spring 2010-2011 caused flooding of the greatest magnitude and duration since reservoir completion. The large magnitude and long duration of this flood made it unlike any flood in recent history and provided a unique …


The Delivery, Speciation, And Fate Of Trace Elements In St. Louis Bay, Mississippi, Gopal Bera May 2014

The Delivery, Speciation, And Fate Of Trace Elements In St. Louis Bay, Mississippi, Gopal Bera

Dissertations

Estuaries are dynamic regions in which there can be significant modification of the riverine flux of trace elements to the open ocean due to various geochemical, physical, and biological processes. Additionally, estuaries are often subject to anthropogenic inputs of trace elements. The first portion of this study investigated the source, behavior, and sediment interaction of anthropogenic stable cesium (Cs) in St. Louis Bay (SLB), MS. A consistent increase in stable Cs concentration was noticed in sediment cores starting from a period when a titanium dioxide refinery on SLB started operations. Weak correlation between Cs and clay percentage and strong correlations …


Biogeochemistry Of Trace Elements In The Mixing Zone Of The Mississippi And Atchafalaya Rivers And Chemical Distributions As Affected By The Deepwater Horizon Blowout, Dongjoo Joung May 2014

Biogeochemistry Of Trace Elements In The Mixing Zone Of The Mississippi And Atchafalaya Rivers And Chemical Distributions As Affected By The Deepwater Horizon Blowout, Dongjoo Joung

Dissertations

Selected trace elements (TEs), dissolved organic carbon, and nutrients were studied in Louisiana Shelf waters including the Mississippi (MR) and Atchafalaya (AR) River plumes during periods of high, intermediate, and low river discharges. Seasonal variations in TEs were observed at low salinity, reflecting seasonal changes in the river water endmembers. Shelf surface water dissolved Mo, Cs, U, Ni, and Cu showed conservative behavior with minor scattering in some high salinity waters. Based on associated mixing experiments, nutrient and chlorophyll distributions, as well as surface-bottom concentration contrasts, the non-conservative behavior of TEs was variously related to colloidal flocculation (Fe, Cr), biological …