Life Sciences Commons^™

Climate Change And Species Interactions Jointly Shape Migration Timing And Growth At A Critical Ontogenetic Transition In Juvenile Sockeye Salmon, Margaret E. Veatch

Honors Theses

Climate change is shifting the timing of biological events globally, but the mechanisms linking environmental variation to phenological changes are poorly understood in many systems, particularly those where individuals undergo ontogenetic habitat shifts. Here, I examined the join influence of climate-driven environmental variability and species interactions migration timing and body size at migration in juvenile sockeye salmon (Oncorhynchus nerka) in Lake Aleknagik, Alaska, using a multi-decadal dataset (1967–2024). Migration timing varied widely among years and was best explained by a combination of ice-out phenology, epilimnetic temperature, and fish densities in littoral habitats. Juvenile sockeye salmon migrated earlier in …

Characterization Of A Highly Arsenic-Resistant Microbe, Eleanor E. Windholz

Honors Theses

Heavy metal pollution in our terrestrial and aquatic ecosystems is a major global concern, as chronic exposure to heavy metals such as arsenic and chromium has dire effects on mammalian health. In these polluted, arsenic-rich environments, microorganisms resistant to heavy metals have been isolated. The microbe isolated in this paper was resistant to As(V) up to 1100 mM, which is significantly higher than most published strains, and resistant to Cr(VI) at concentrations up to 5 mM. The microbe was tentatively identified as Micrococcus luteus, but its high arsenic resistance suggests it may be a novel strain. The ability of the …

An Apple A Day: Have The Growing Conditions Of Apples In Maine Changed Over The Past 20 Years, Anooshka Sethi

Honors Theses

Climate change is increasingly affecting the growing conditions that farmers face. This study focused on if and how the growing conditions of apples have changed over the past two decades. Apples are an economically, socially, and culturally important crop to Maine's agriculture landscape. By production acreage, Maine is the second largest state in New England, with 2700 acres of land used to grow apples (USDA NASS CoA, 2022). A unique characteristic of agricultural production in Maine is that most farms are small-scale, run by families or small groups, making adverse changes to the growing conditions of a major crop in …

Effects Of Direct And Indirect Predator Cue Intensity On Foraging Decisions In A Deer Mouse, Peromyscus, Nicholas G. Levinson

Honors Theses

Ecologists developed optimal foraging theory as a framework to understand how an animal may spend minimal time to maximize resource intake. A giving-up density (GUD) is a metric of the density of remaining food in a food patch at which an animal decides foraging is no longer economical. This study aims to test how the intensity of direct and indirect predator cues alter foraging patterns of deer mice. To measure GUD, I used depletable food patches deployed in the “upper woods” on the periphery of Colby College. To simulate direct predator cues, 1 mL of fox urine was applied on …

Characterization Of Serx: A Putative Periplasmic Binding Protein In A Selenate Respiring Bacteria, Henry Jacques, Susan E. Childers

Honors Theses

A selenate respiring bacterium, Dechloromonas sp. A34, was isolated from a seleniferous mining site in southeastern Idaho. A34 was of interest due to its ability to respire up to 20 mM selenate, the highest concentration tested. The strain has been proposed to represent a new species of bacteria within the Dechloromonas genera, with the prospective name Dechloromonas selenatirespirans (manuscript in preparation). Our research presents characterization of a putative periplasmic binding protein found within an operon that contains genes encoding a putative selenate reductase. The gene, named serX (selenate reductase gene X), is 855 base pairs and encodes a putative …

Northern Shrimp In The Gulf Of Maine And The Impacts Of Climate Change, Alicia Hober

Honors Theses

Northern Shrimp (Pandalus borealis) populations within the Gulf of Maine collapsed in 2011 following the first year that sea surface temperature surpassed 10ºC. The population collapse resulting in a moratorium in 2014. The waters of the Gulf of Maine have been rising at a rate of 0.045ºC per year, changing predator distribution, prey distribution, as well as Northern Shrimp biological variables. There has been very little recovery to the Northern Shrimp stock despite the fishing moratorium and the answers behind the collapse and lack of recovery remains enigmatic. Therefore, this two-chapter study includes a literature review and a …

Felling For Photovoltaics: Remote Sensing For The Detection Of Solar Facilities In Maine, James A. Lane

Honors Theses

Solar power is an area with increasing development in the State of Maine. Photovoltaic solar, which uses large arrays of panels constructed on facilities of several hectares, is an ideal renewable energy source for Maine, because of its low population density and small proportion of conserved lands. Since most of the state of Maine is forested, the development of photovoltaic solar will require increasing amounts of deforestation. Environmental impacts of this deforestation include loss of carbon sequestration, erosion, damage to habitat, and inhibition of other forest benefits. This study uses Landsat data and remote sensing to analyze a large portion …

Reviving Caribbean Scleractinian Corals: Medication In Ex-Situ Care, Christopher E. Cho

Honors Theses

The Caribbean basin is facing an unprecedented decline in coral reef health, with factors such as coral disease, climate change, and algal overgrowth contributing to the deterioration of these vital ecosystems. In response, land-based facilities have emerged to aid in coral conservation and restoration efforts. One aspect of these conservation efforts involves the treatment of coral ailments, which is still an emerging field within coral conservation. By medicating corals, researchers aim to combat diseases and alleviate stressors that threaten coral health. This practice holds promise for preserving genetic diversity and supporting future repopulation initiatives. This study evaluates the effectiveness of …

Modification Of Marine Snail Microhabitats By Canopy-Forming Algae, Eleanor Mcgrath

Honors Theses

Brown algae, including the canopy-forming macroalgae Fucus distichus, are declining in abundance around the world due to stressors associated with climate change. Local extinction of Fucus impacts the intertidal community through cascading effects as the ecosystem loses a dominant primary producer at the base of the food web. However, Fucus is not only a resource species; it is also an ecosystem engineer. This thesis investigates the effect of Fucus extinction on the abundance of two herbivorous marine snails, L. saxatilis and L. obtusata, with a focus on the role of Fucus as a habitat- modifier. Specifically, I explored: …

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 …

Does Tssh Deletion In Paraburkholderia Bonniea Affect Its Symbiosis With Dictyostellum Discoideum?, Anna Chen

Honors Theses

Paraburkholderia are amoeba resistant, gram negative bacteria that form facultative symbiotic relationships with D. discoideum, a soil dwelling amoeba host. Three species of Paraburkholderia, P. agricolaris, P. hayleyella, and P. bonniea are able to persistently infect nonnative, or symbiont free, D. discoideum. These three species share a type III secretion system (T3SS) and type VI secretion system (T6SS) that is absent in other close relatives We hypothesized that the ability to persistently infect D. discoideum may be partially attributed to the T3SS and T6SS shared across the three species of Paraburkholderia.

The goal was to test the phenotypic effect of …

Changes In Ecosystem Processes And Functional Traits Over An Elevational Gradient, Tiana Issa

Honors Theses

Elevation gradients have been used to understand how climate change impacts various ecosystems processes by substituting distance across elevation with time, reflecting a previous, colder climate. To monitor the changes in soil organic carbon (SOC), plant community, and functional traits across time in the face of climate change, this study used space-for-time substitution to emulate a long-term study with elevational gradients and revisited the same gradient for nearly two decades to monitor elevational effects across time. With this research, I aim to answer the following questions: (1) How does elevation impact ecosystem processes and alpine plant traits? (2) How does …

The Effect Of Blue Mussel (Mytilus Edulis) Extinction On Ecosystem Function In The Gulf Of Maine Rocky Intertidal, Sophia K. Montague

Honors Theses

Stressors associated with climate change including thermal stress and ocean acidification inhibit the growth and reproduction of many species, including the ecologically and economically important blue mussel species in the Gulf of Maine (GOM). Established scaling relationships between mussel size, abundance, and water filtration suggests that the decline of mussels will stunt GOM water filtration. This change in the rate of water filtration could have large effects on the abundance of phytoplankton, abundance of invertebrate larvae, abundance of nutrients and organic material, food web stability, and biodiversity. Overall, this thesis explores the effect of blue mussel (Mytilus edulis) …

Testing Evolutionary Conservation Of Sex Determination In Lepidoptera Using Crispr/Cas9 Gene Editing, Sophia Schroeder

Honors Theses

The mechanism of sex determination in Lepidoptera is largely unexplored, and limited to knowledge of only a few genes. Adult Lepidoptera have obvious sexually dimorphic qualities, such as their genitalia. However, significant sex determination genes are not imperative for the adult developmental stage. Knockouts of some sex determination genes (doublesex isoforms) are shown to be lethal in the embryonic and larval stages of development in several animals. However, it is unclear whether this is due to their respective impact on sex determination and sexual dimorphism, or the existence of another function, such as pleiotropy, within a particular gene. Moreover, …

Trends In Cyanotoxin Production Potential In China Lake: An Edna Analysis Of Microcystis And Dolichospermum And The Environmental Drivers Of Cyanotoxin Production, Gennifer M. Rubin

Honors Theses

Episodes of cyano-harmful algal blooms (cyano-HABs) are hypothesized to be exacerbated by the effects of climate change. However, the dynamics of the interactions between elements of climate change and toxigenic cyanobacteria proliferation are not well defined. China Lake is the drinking water source for 7 municipalities in the Kennebec County and is one of many lakes in central Maine that has been subjected to high levels of cyano-HABs and microcystin toxin contamination in recent years. Monitoring the toxicity of these blooms in relation to various aspects of climate change may lead to identification of the major drivers of microcystin production …

Biomechanics Of Mantis Prey Capture, Danielle S. Taylor

Honors Theses

Mantis species have a variety of different morphologies, so do the extreme forms of mantis limbs trade prey catching capability for camouflage? We hypothesize that some extreme forms of mantis limbs that are associated with cryptic species may be associated with a tradeoff of the capability of those limbs. Previous research has developed 2D morphologies of several hundred species of mantises. We are creating a 3D morphology by using micro dissection, micro CT imaging to construct our 3D biomechanical model. We found the attachment points of the ligaments and muscles from a Tenodera forearm and have constructed a 2D biomechanical …

Legacies Align With Colby’S Acquisition Of Allen And Benner Islands, Bob Keyes

Colby Magazine

The College creates a 500-acre island campus in Muscongus Bay

Banned But Still Toxic: Gail Carlson Serves Notice That Chemical In Ski Racers' Waxes Still Lurk At The Starting Line, Bill Donahue

Colby Magazine

We live in a chemical world, exposing ourselves all day long to scary toxins created in laboratories—to the traces of herbicide that lurk in our water, to the carcinogenic Teflon coating our cookware, and to the pesticides sprayed on our vegetables.

A New Window Into Children's Memory: Professor Of Psychology Martha Arterberry's New Study Comes With Implications For Eyewitness Testimonies, Kardelen Koldas

Colby Magazine

When children are eyewitnesses—to an incident, an accident, or a crime— does age matter? Are older kids more precise in recounting an event than the younger ones?

Rapid Response: Cat-Scan Machine And 3d Printers Vital In Covid-19, Laura Meader

Colby Magazine

Colby’s Assistant Professor of Biology Josh Martin is using his expertise and sophisticated scientific equipment to create face shields, respirator masks, and air filter cartridges for local first responders and hospitals in need of equipment that is crucial to treating patients with COVID-19.

Developing A Circuit Model To Study The Mechanisms Of Dna Damage And Repair Feedback Dynamics In Cancer Cells, Thomas M. Deangelo

Honors Theses

Cancer therapies over the last decade have promoted a growing interest in the manipulation of DNA damage and repair pathways due to its beneficial consequences on cancer cell viability. Simultaneously attacking genetic code with DNA-damaging chemotherapies while eliminating mechanisms of DNA repair – the protectors of our genome – has enormous therapeutic potential. Biological circuit engineering interfaces biochemistry and systems biology with electrical engineering analyses to accurately model and simulate biological pathways such as DNA damage and repair. Circuit models can also be used to identify weaknesses within pathways, highlighting the most efficient protein targets for drugs that aim to …

Challenges Of Constructing Entrainment Map For Arbitrary Circadian Models, Yuxuan (Nelson) Wu

Honors Theses

The entrainment map, developed by Dr.Diekman and Dr.Bose, is claimed to be a 1-dimensional map that produces a better prediction for phase-locking than methods than the phase response curve for circadian models. In his paper, he constructs the entrainment map for the two-dimensional circadian model, the Novak-Tyson model, and the other two higher-dimensional circadian models. For this thesis, we concentrate on exploring if it is viable to construct the entrainment map for other circadian models that are not included in his paper: the Becker-Weimann model and the Relogio model. In addition, we discuss the challenges of constructing the entrainment map …

Pfas Environmental Contamination In Central Maine, Megan H. Andersen

Honors Theses

PFAS (per- and polyfluoroalkyl substances) are toxic, persistent, and bioaccumulative chemicals that are used in a variety of consumer products and industrial applications. Paper mills across the state of Maine have used PFAS in their industrial paper making processes, and their wastes often flow for treatment into municipal sewage treatment facilities. PFAS contaminated municipal wastewater from the general use of PFAS consumer products are also processed by these plants. Liquid waste is condensed into solid waste septage and sludge, and in what was thought to be an environmentally friendly repurposing practice, municipal sludge and septage has been spread on plots …

Community Interventions To The Food Insecurity Crisis Inuit Currently Face In Nunangat, Alyssia R. Getschow

Honors Theses

Inuit living in Nunangat, a northern territory in Canada, are facing unprecedented rates of food insecurity. The increasing impacts of anthropogenic climate change are rapidly changing the Arctic landscape in Nunangat, posing challenges to Inuit hunters who hunt and live completely self-sufficient off of the land. This lack of access to country foods and the impacts these conditions are having on Inuit communities are forcing Inuit to consider aid propositions from the Canadian government. Due to a long history of conflict with white settlers during the colonization of Canada, there is a feeling of distrust and cultural distaste between Canada …

Characterizing Cellular Stress, Hippocampal Function, And Behavior In A Novel Rat Model Of Alzheimer's Disease, Anne A. Schulman

Honors Theses

Alzheimer’s Disease (AD) is a progressive neurodegenerative disorder that affects over 5 million individuals in the United States alone. While AD is primarily thought of as a disease that destroys neural networks required for memory recall and formation, AD also cause impairment in emotional regulation, cognitive flexibility, and executive function pathways. The cause of AD is unknown; however, the allele ApoE4 has been identified as a risk factor for the onset of AD. ApoE4 provides a valuable opportunity to study AD through animal models. This thesis utilized a human ApoE4 transgenic rat model (hApoE4) to investigate the biological and behavioral …

Modeling Jadera Haematoloma’S Phenotypic Variation In The Context Of Its Developmental Plasticity, Michael C. Yorsz

Honors Theses

Phenotypic plasticity is the ability of an organism to integrate information from environmental cues to inform the development of its phenotype and remains understudied in biology. Models of plasticity are needed because evolution in the presence of plasticity is poorly understood. Jadera haematoloma, a hemimetabolous true bug, is an excellent animal model of plasticity, exhibiting a non-linear plastic response to juvenile nutrition that biases adult development into groups with differences in flight capability, wing shape, and fecundity. However, there is a lack of literature consensus regarding the range of developmental outcomes in the species. Some publications report the presence …

Doors Pushed Open: For Devin Gibbs, College Seemed Like A Longshot--Until It Wasn't, Kardelen Koldas

Colby Magazine

Before enrolling, Devin Gibbs ’14 received an invitation from Colby. The letter offered to bring him to campus and provide accommodations so he could get a feel for the school. What it didn’t say was he had, in essence, been admitted. Gibbs, who lived in Waterville just minutes from campus, thought the letter was a scam. “I had never gotten anything for free before,” he said.

A Better Way, Gerry Boyle

Colby Magazine

Alane O’Connor ’96 studied environmental economics at Colby. Associate Professor of Statistics Liam O’Brien first studied physics and mathematics.Together the pair has combined their broad experience to produce groundbreaking research that is changing the way clinicians around the world treat pregnant and opioid-addicted women and their unborn children.

One Step At A Time: Robotics Lab Team Combines Talents In Quest For The Perfect Synthetic Tendon, Laura Meader

Colby Magazine

When Caitrin Eaton arrived at Colby a year ago, she named her new robotics lab C3PO. The name grabs students’ attention, but they’re drawn to the lab for another reason: Eaton’s cutting-edge research unites engineering and animal physiology to help robots walk more smoothly than Hollywood’s stiff-legged C-3PO robot.

The Quantitative Assessment Of Pond Scum: An Examination Of The Biogeochemistry Of Phosphorus Cycling In The Belgrade Lakes, Abbey M. Sykes

Honors Theses

The internal recycling phosphorus in freshwater lake bottom sediments represents a significant source of hypolimnetic phosphorus (P) release for many of Maine’s lakes. In summer months, Maine lakes often thermally stratify and the lake hypolimnion develops anoxia, leading to a reduction in redox potential at the sediment-water interface. These reducing conditions facilitate the reductive dissolution of ferric iron, and, since phosphorus is often present in freshwater lake sediments as solid FeOOH-PO₄ complexes, results in release of soluble phosphorus into the water column. Our current study presents field and laboratory data from sediment fractionation extractions designed to quantify concentrations of …