Physical Sciences and Mathematics Commons^™

Pollutants And Foraminiferal Assemblages In Torrecillas Lagoon: An Environmental Micropaleontology Approach, Michael Martinez-Colon

USF Tampa Graduate Theses and Dissertations

Torrecillas Lagoon in the North Coast of Puerto Rico has experienced extensive anthropogenic influence over the past 400 years. Elevated concentrations of Potential Toxic Elements (PTEs) have been reported in surficial sediments. The main goal of this dissertation was to implement in Puerto Rico the use of benthic foraminifers as a bioindicators of PTEs and to compare the impact of Cu(II) on field samples with results of experimental work using cultures.

Analyses included geochemical assessment for bulk and carbonate- soluble bioavailable concentrations of PTEs in surface, core and pore-water samples, as well as analyses of grain-size, Percent Total Organic Carbon …

Ecological Niche Modeling Of The North American Giant Salamander: Predicting Current And Future Potential Distributions And Examining Environmental Influences, Selena S. Roark

Electronic Theses and Dissertations

North American Giant Salamanders (Cryptobranchus alleganiensis), commonly known as hellbenders, have been experiencing a population decline for decades due to human influences, such as pollution and habitat destruction. Many efforts are underway to save the hellbender but their entire potential geographical range has not been well-studied. Currently, hellbender populations are delineated by county boundaries and are on the International Union for Conservation of Nature Red List. The Genetic Algorithm for Rule-set Production, an Ecological Niche Model, was used to model the current hellbender potential distribution at a macro-scale under two different environmental scenarios. Additionally, future potential distributions were …

Reef Fish Spatial Distribution And Benthic Habitat Associations On The Southeast Florida Reef Tract, Dana Fisco

HCNSO Student Theses and Dissertations

The Florida Reef Tract (FRT) extends from the tropical Caribbean up the southeast coast of Florida into a temperate environment where tropical reef assemblages diminish with increasing latitude. This study used data from a three-year comprehensive fishery-independent survey to quantify reef fish spatial distribution along the Southeast FRT and define where the assemblage shifts from tropical to temperate. A total of 1,676 reef fish visual census samples were conducted to assess the populations on a stratified-random selection of sites of marine hardbottom habitats between the Miami River and St. Lucie inlet. Multivariate analyses were used to investigate differences in assemblages …

Chemical Investigation Of Antarctic Marine Organisms & Their Role In Modern Drug Discovery, Jacqueline Lee Fries

USF Tampa Graduate Theses and Dissertations

The chemicals produced by biological systems, whether proteins, peptides, or terpenes, will always provide an intriguing topic for researchers. Invisibly controlling every aspect of nature, these molecules are responsible for life, evolution, and death. Specifically, here is described the secondary metabolites produced by Antarctic marine organisms as well as others, and how they are used to defend or attract other animals while potentially providing health benefits to mankind. This is done through collection, extraction, and separation of individual specimens. The respective mixtures of compounds after isolation are then analyzed via spectroscopic methods such as nuclear magnetic resonance spectroscopy, mass spectrometry, …

Ecology Of Two Reintroduced Black Bear Populations In The Central Appalachians, Sean Mccarthy Murphy

Theses and Dissertations--Animal and Food Sciences

Reintroduced populations are vulnerable to demographic and environmental stochasticity, deleterious genetic effects, and reduced population fitness, all of which can increase extinction probability. Population viability is principle to determining the status of reintroduced populations and for guiding management decisions. To attempt to reestablish black bear (Ursus americanus) populations in the central Appalachians, two reintroductions using small founder groups occurred during the 1990s in the Big South Fork area along the Kentucky-Tennessee border (BSF) and in the Jefferson National Forest along the Kentucky-Virginia border (KVP). My objectives were to estimate demographic and genetic parameters, and to evaluate long-term viability …

Vegetation Influences Microbial Community Structure And Methane Emissions In Southeastern Louisiana Wetlands, Anthony Jason Rietl

LSU Doctoral Dissertations

Methane has a warming potential 28 times that of carbon dioxide and has been increasing in the Earth’s atmosphere since 1750. An understanding of the dynamics of methane emissions from natural sources is becoming increasingly important as we may need to mitigate emissions from these sources in the future to help reduce the effects of climate change. Wetlands are the single largest natural source of methane; however, little attention has been given to how plant species, biota, and interactions between above and belowground communities and microbial communities may affect methane emissions. First, microbial community structure and function was assessed for …

Soil Properties Affect Establishment Of Invasive Species, Celastrus Orbiculatus, In A Lower Hudson River Riparian Ecosystem, Shabana Hoosein Hoosein

Legacy Theses & Dissertations (2009 - 2024)

The Hudson River Estuary has been colonized by numerous terrestrial invasive plant species, due in part to its history of anthropogenic and natural disturbance riparian dynamics. This study investigates the spatial patterns of a widespread invasion by Oriental (or Asiatic) bittersweet (Celastrus orbiculatus Thunb.) in Schodack Island State Park, Rensselaer and Columbia Counties. The Park is home to rare species and communities, several of which are threatened by the encroachment of bittersweet. Bittersweet populations were mapped and surveyed on a fixed grid throughout the island, to determine distribution patterns. Stem densities were approximately 50% higher in sites with dredged material …

Mechanisms Of Antixenosis And Antibiosis Of Ash Against Emerald Ash Borer, Chad Michael Rigsby

Browse all Theses and Dissertations

Emerald ash borer (EAB), Agrilus planipennis (Coleoptera: Buprestidae), is an invasive forest pest causing widespread mortality of ash (Fraxinus spp.) in North America. Host resistance research and the development of resistant hosts offers a promising strategy for the long-term conservation of ash and management of EAB. Manchurian ash (F. mandshurica) shares an evolutionary history with EAB in Asia, resulting in its greater resistance relative to naive North American ashes. In the following studies I investigate antixenosis and antibiosis mechanisms of resistant and susceptible ashes. Antixenosis in Manchurian ash was demonstrated by quantifying substantially lower oviposition on this species relative to …

Seasonal Habitat Selection Of The North American Porcupine (Erethizon Dorsatum) In A Coastal Dune Forest, Cara L. Appel

Cal Poly Humboldt theses and projects

Wildlife-habitat relationship studies are important for understanding the factors that determine where species occur in space and time. Habitat selection by generalist species should be studied on fine spatial and temporal scales to avoid masking important differences between seasons, localities, or orders of selection. I conducted the first study of habitat use and general ecology of North American porcupines (Erethizon dorsatum) in a coastal dune environment. Specifically, I assessed changes in body mass, home range size, and habitat selection in relation to the potential for seasonal nutritional and survival bottlenecks as reported elsewhere. Although they are considered generalists, …