Other Ecology and Evolutionary Biology Commons^™

Effects Of Increased Salinity On Mississippi Coast Bacterial Community Composition And Diversity, Clifton C. Wade

Honors Theses

Bacterial communities are important to ecosystem function in coastal environments, but the response of these communities to short term increased salinity conditions is understudied. This study utilized a microcosm setup to investigate the response of coastal seawater bacterial communities to three treatments: an unamended seawater control, a reference treatment that received reverse osmosis (RO) water, and an elevated salinity treatment that received artificial seawater dissolved in RO water. Microcosms were sampled four times over a five-day period to analyze the effects of time under different salinity conditions on the seawater bacterial community. 16S rRNA gene sequencing was used to analyze …

Ectomycorrhizal Fungal Identity Strongly Influences Soil Properties Relative To Pine Presence And Soil History In A Pine–Eucalyptus System, Braedan Watters

Honors Theses

Invasive Pinus radiata has increasingly spread into native ecosystems in the Southern Hemisphere, including Eucalyptus forests in Australia, where it forms novel hybrid forest systems in which invasive and native tree species coexist. The success of these invasions is closely tied to ectomycorrhizal fungi (EMF) such as Rhizopogon spp., yet the relative roles of pines versus their fungal symbionts in altering soil properties remain poorly understood. This study investigated the independent and interactive effects of soil history (Pinus or Eucalyptus), EMF identity, and pine presence on soil properties using a controlled factorial experiment. Soil from beneath either Pinus …

Quantifying Genetic Diversity In Nematode Feeding Rate, Jacob King

Honors Theses

Understanding how populations persist under changing environmental conditions is a central question in ecology and evolutionary biology. Variation in traits related to resource acquisition may play a key role in determining population survival when resources are limited or fluctuate over time. In this study, I investigated how variation in feeding-related traits influences population persistence using a combination of computational modeling and laboratory experiments. I developed a stochastic, individual-based consumer–resource model to simulate population dynamics across varying levels of trait variance and resource regimes. Across 60,000 simulated populations, increased trait variation consistently reduced extinction risk and extended persistence time, although the …

Bottles, Butterflies, And Biomass: Recycled Glass Sand, Microbial Additions, And Herbivory Effects On Milkweed Growth, Kealey Skinner

Honors Theses

Plant-soil-microbe interactions are integral components of ecological networks and drive ecosystem function from the bottom-up. Whereas herbivores regulate ecosystem function from the top-down, having opposing and potentially complementary effects on ecosystem function. My thesis sought to understand how below-ground microbial communities contribute to herbivore preference and plant biomass across varied soil substrates. My thesis asked: how do substrate and soil microbial communities influence herbivore preference and plant biomass accumulation on swamp milkweed (Asclepias incarnata)? To address this question, seedlings of A. incarnata were sown in 2.5 cm wide × 10 cm deep pots filled with either natural beach sand or …

Acute Effects Of The Psychoactive Pollutant Fluoxetine On The Antipredator Behavior Of The Gulf Killifish (Fundulus Grandis), Semyra Reus

Honors Theses

Pharmaceutical contaminants are increasingly prevalent in aquatic environments, yet their sublethal effects on ecologically relevant behaviors remain poorly understood, particularly in estuarine systems. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are of particular concern due to the conserved role of serotonin in regulating behavior across vertebrates. Here, we investigated how acute exposure to environmentally relevant concentrations of fluoxetine influences anti-predator behavior in Gulf killifish (Fundulus grandis), a key estuarine fish commonly found in saltmarsh habitats. Killifish were exposed to control (0 ng/L), low (17.8 ng/L), and high (596 ng/L) fluoxetine concentrations and subsequently tested in the presence …

Ghosts In Glass: Ghost Crabs As Judges Of Glass Sand For Coastal Restoration, Emily Parrish

Honors Theses

Over 60% of the Gulf of Mexico coastline is actively eroding, which has resulted in thousands of miles of lost coastline over the last 100 years. This drastic loss of coastal land highlights the dire need for coastal restoration across the entirety of the Gulf Coast. A vital aspect of restoring these eroded areas is replenishing eroded substrate, traditionally conducted through offshore dredging of substrates which comes with high economic and ecological costs. Recycled glass sand may be able to fill this role and reduce our reliance on dredging while lowering the amount of glass waste entering landfills each year. …

Development Of A Course-Based Undergraduate Research Experience (Cure) Using The Bess Beetle, Sreya Maddali

Honors Theses

Participating in scientific research has increasingly been important in helping students develop necessary science learning skills, like critical thinking. One way of introducing students to these experiences is a Course-based Undergraduate Research Experience (CURE). CUREs enable students to improve in similar ways to internships and are more accessible to students from diverse backgrounds. The goal was to create a CURE centered around ecological genetics, using the Bess Beetle (Odontotaenius disjunctus) as the focal organism of a 16-week course. This species was selected because of its wide geographic range and divergent genetic lineages based on mitochondrial cytochrome oxidase subunit 1 (COI) …

Fiddler Crab Gut Microbiomes As An Indicator For Eutrophication Due To Waste-Water Contamination In Estuaries, Madison L. Geraci

Honors Theses

Estuaries are unique biogeochemical zones in coastal systems that provide a myriad of ecological functions: providing habitat for critically important fishery species, diverse species of plants and animals, and contributing to nutrient cycling. Estuaries are vulnerable to anthropogenic stressors as they are intersections between marine and terrestrial communities and are often the hotspot of coastal development and activity. Estuarine sediments act as repositories for anthropogenic contaminants, including excess nutrient runoffs and waste-water pollution that can cause states of eutrophication. Microorganisms are sensitive to these environmental changes, presenting a unique opportunity of being useful bioindicators of environmental stress. Isolating microorganisms from …

Measuring Nature’S Contributions To People Provided By Species In The Gulf Of Maine Rocky Intertidal Ecosystem, Madelyn L. Eippert

Honors Theses

Ecosystem services aim to quantify the value of nature provided to humans. However, Ecosystem services are typically measured at the level of the ecosystem as a whole and do not consider interactions between species in an ecosystem. Ultimately, the species in an ecosystem determine the services that are provided. Measuring ecosystem services at the landscape level misses the complex interactions and changing biodiversity of ecosystems. Currently, there is no accepted framework to link ecosystem services to species. In this thesis, I developed a framework to link Nature’s Contributions to People (NCP) to species. NCP includes 18 specific contributions (i.e. 18 …

Striped Blenny (Chasmodes Bosquianus) Behavior And Shelter Use In A Southeastern Salt Marsh Tidal Creek, Brooklyn Johnson, Juliana Harding

Honors Theses

Temperate estuaries are important habitats for resident species and maturing juvenile transient fishes. The North Inlet estuary, SC resident fish fauna includes the Striped Blenny (Chasmodes bosquianus) and Crested Blenny (Hypleurochilus geminatus). Individual blenny males occupy habitat shelters year-round. During breeding season, blenny males attract mates to nest and protect developing embryos within the nest. Salinity requirements establish blenny spatial distribution in the estuary. Seasonal spawning activity by these temperate blenny species is related to water temperature and seasonal productivity patterns. Blenny nest site occupancy patterns relative to the lunar cycle, water depth, and salinity were …

An Experiment To Test For Rapid Evolution In An Introduced Ectomycorrhizal Symbiosis, Valerie Rewa

Honors Theses

The rapid evolution of introduced ectomycorrhizal-plant partnerships is an under- explored topic that may have immense impacts on ecosystems around the world. This experiment sought to identify and quantify this evolution and its impacts on both fungal colonization as well as plant growth. I used a laboratory experiment to analyze these factors in native and exotic genotypes of Suillus cothurnatus and Pinus species. Much of the data was not able to be collected, but that which was did not support the presence of rapid evolution in the mutualistic partnership. Pine species was seen to have a significant effect on plant …

Density Dependent Growth Of Pseudomonas Fluorescens In The Presence And Absence Of C. Elegans Predation In Liquid Media, Jack Landmann

Honors Theses

The purpose of this study was to understand the predator-prey relationship between C. elegans worms and P. fluorescens bacteria in liquid media. We were aiming to create a predation model of the relationship between these two species.

This study was performed through three experiments. Using 96-well plates, we were able to measure the change in optical density (OD) of these wells and calculate the growth rate. This growth rate was then graphed and analyzed. The first experiment contained P. fluorescens and KB liquid media, this study demonstrated that the bacterial population has a carrying capacity. We were also able to …

Warming Stimulates Sporulation Rates And Alters Community Structure Of Litter-Associated Fungi In Streamside Channel Experiment, Kaitlin D. Beasley-Polko

Honors Theses

Fungi, such as aquatic hyphomycetes, are important decomposers of plant litter in temperate forested headwater streams providing energy and nutrients for the higher trophic levels in these ecosystems. According to current climate change predictions, stream water temperatures are expected to rise significantly in the near future. This project addressed the effects of temperature on sporulation rates and community structure of aquatic hyphomycetes on substrates of different carbon quality (maple and rhododendron leaf litter and wood veneers). The experiment was conducted in streamside channels fed with stream water (ambient, +2°C and +4°C) and set up to mimic small streams. We found …

Impact Of The North American Monsoon On Molt Migrant Passerines, Liuqingqing Yang

Honors Theses

Breeding, molt, and migration place considerable yearly demands on migrating passerines in North America. Due to conflicts in energy allocation, many species have evolved migration strategies that prevent temporal overlap in these processes. However, there is recent evidence that some passerines which breed in western North America migrate to intermediate stopover sites to carry out molt, conflating molt and migration. Factors influencing the evolution of such a strategy are believed to include both aridity on breeding grounds and dependable flushes of late-summer productivity in the southwestern United States and northwestern Mexico. This productivity occurs due to the brisk rainfall of …

Blenny Territoriality At Oyster Landing, North Inlet Estuary, South Carolina: Seasonal Patterns And Ecological Factors, Sydney Davis, Juliana Harding

Honors Theses

Temperate oyster reef blennies use oyster shells that are still articulated as habitat year round. During the breeding season when water temperatures are > 18-20°C, many species of blenny males use the oyster valves as nesting sites. Male blennies exhibit territorial behavior when guarding their nesting sites and can interact differently with conspecific and transient species. Striped blenny (Chasmodes bosquianus) and freckled blenny (Hypsoblennius ionthas) behavior was described from April 2020 to August 2020 at Oyster Landing, North Inlet estuary, South Carolina to quantify typical blenny behavior, general presence or absence of residents, and potential environmental parameters …

Development Of Methods To Track Oyster Movement Under Field Conditions In North Inlet Estuary, South Carolina, Alyssa M. Leclaire

Honors Theses

Eastern oyster (Crassostrea virginica) reefs provide important habitat structure and ecosystem services in saltmarsh tidal creek estuaries. Reef persistence depends on growth of resident individuals and regular recruitment to maintain suitable shell substrate. Boat wakes potentially physically displace oyster clumps. The objective of this research was to develop methods to track oyster clump position and biomass on two natural fringing oyster reefs in North Inlet estuary, South Carolina. Boat traffic (number of boats making wakes per day), oyster clump displacement (cm/d) over time, oyster biomass (g dry tissue), and condition index (biomass/g dry shell weight) were quantified from …

Predation Effects On Mid-Marsh Ribbed Mussel Mortality, Cluster Size, And Facilitation Of Cordgrass Growth, Colten Winter, Keith Walters

Honors Theses

Reciprocal facilitation between Geukensia demissa, ribbed mussels, and Sporobolus alterniflorus, cordgrass, has a positive effect on salt marsh ecosystems. Mussel clusters enhance cordgrass growth and drought resistance and cordgrass provides attachment and shade for mussel aggregations. Along with benefits for both mussels and cordgrass, the mutualism facilitates increased biodiversity and shoreline stabilization and enhances marsh ecosystem functions. Aspects of mussel patch configuration including cluster size, perimeter and connectivity modulate the reciprocal facilitation effects of cordgrass and mussels on marsh ecosystems. In a northern South Carolina marsh system, mussel patch configuration positively influenced cordgrass biomass. Predation affected mussel patch …

Density And Species Richness Of Macrofaunal Benthic Bivalves In North Inlet Estuary, South Carolina, Richard Hawley, Juliana Harding

Honors Theses

Marine benthic bivalves are consumed by higher trophic levels. Bivalve species richness and density depend on temperature, salinity, and location. Biweekly core samples were collected from Bly Creek from 12/2017 to 12/2018. Benthic macrofaunal bivalves were counted and identified to describe density and species richness. Bivalves were also photographed for species identification. Bivalves composed 0% to 17% of the total macrofauna. The maximum bivalve density (8,149 bivalves/m²) was recorded on December 23, 2018. The fewest bivalves were observed from December 2017 through March 2018. Eight bivalve species were recorded during 2018; at least one species was present year-round. …

Demersal Fish Use Of Printed Oyster Shells As Nesting Habitat In North Inlet Estuary, Sc, Annie Boyd, Juliana Harding

Honors Theses

Temperate estuarine blenny species establish subtidal territories and nesting sites. Four blenny species co-occur in North Inlet, SC including the striped blenny, Chasmodes bosquianus, crested blenny, Hypleurochilus geminatus, feather blenny, Hypsoblennius hentzi, and freckled blenny, Hypsoblennius ionthas. All four fishes use empty oyster (Crassostrea virginica) shells as nesting sites. Current 3D printer technology was used to create standard nest substrates to describe relationships between blenny habitat use and nest site dimensions. Replicate printed shells of 2 gape widths (5, 7 mm) for each of 2 shell cavity volumes (22 mL, 15mL, Oyster A and …

Sibship Reconstruction For Inferring The Number Of Breeders Of Gulf Sturgeon In The Apalachicola River, Robbilyn Verges

Honors Theses

The Gulf sturgeon is an anadromous fish that inhabits the Gulf of Mexico and its neighboring river drainages. The species is currently listed as threatened due to habitat alterations and overfishing. In this study, we focused on the Apalachicola River in Florida, which has had several historic spawning locations of the sturgeon blocked by the Jim Woodruff Lock and Dam. Age-1 juvenile sturgeon from the year 2013 (n=31) and 2014 (n=131) were genotyped using fourteen microsatellite loci. Sibship reconstruction and parentage assignment was performed in order to determine the effective number of breeders (Nb) and the total number of spawning …

Biomass Energy At Colby College, Rachel E. Baron

Honors Theses

In light of growing concern regarding the effects of global climate change, Colby College signed the American College and University Presidents’ Climate Commitment (ACUPCC) in 2008. Through this pledge, Colby has committed to reducing carbon emissions in its Climate Action Plan (IPCC 2007; CCAP 2010). The College seeks to be carbon neutral by 2015 (CCAP 2010). This will be accomplished through a variety of mechanisms, one of which includes the construction of a biomass facility to replace most of the oil currently used for heating (CCAP 2010).

Anthropogenic global climate change has been documented by many scientists, but was widely …