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Celebration of Learning 2021 poster presentations by major, A-H

Here are poster presentations from the 2021 Celebration of Learning by major, A-H. Also see the quick guide to posters, and posters by majors I-Z.


Amber Hanke: Queer & Colonized: How Colonization Impacted Gender Diversity

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Advisor: Dr. Adam Kaul

Abstract: The recognition of a third gender is not new in human societies. Prior to colonization, many indigenous societies acknowledged three or more genders. Gender was not binary and gender roles were not fixed. Third gender individuals sometimes held important roles in their communities. However, when these societies were colonized, their spectrum of gender was forced to fit into the western gender binary because colonizers did not accept individuals who were outside of the binary.

Third gender individuals suffered as they were policed to fit into the binary. Using a multi-disciplinary approach of Anthropology and Women & Gender studies and a mixed methodology incorporating narratives and maps, this project examines three societies whose third gender categories — Two-Spirited, Muxes, and Hijras — were impacted by colonization. It is important to understand how the erasure of gender diversity has marginalized many individuals who face violence on a daily basis within their communities today.

Natalia Czachorowski: The Hispanic Diaspora in the Quad Cities: How Soccer Reinforces Identity Construction

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Advisor: Dr. Carrie Hough, Senior Inquiry project

Abstract: My own experiences with soccer and identity, being a first-generation Polish-American, made me realize that most athletes view soccer like any other sport – a way for them to physically and mentally exert themselves. For some, participation in sports, like soccer leagues, is a way to create identity, both mobile and place identity, as well as a sense of belonging.

Soccer leagues can be seen as a built environment in which a culture(s) is bound to a place, making it the ideal place for various processes like identity construction to occur. Various cultural customs and practices like language and food can be present in these built environments, as was seen during data collection. Some of these cultural aspects are repeated, like the use of jerseys identical to those of professional teams to resemble one’s own team, making them more ritual-like.

My interest in a Quad City soccer league, locally known as the Mexican league, is a place for Hispanic and non-Hispanic men between ages 16 to about 50 years of age to play competitive soccer. These concepts were seen to various degrees within the league and overall provided a way for participants to affirm their ethnic identities.


Jordan Delinski: Same But Different

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Advisor: Kelvin Mason, Senior Inquiry project

Abstract: The goal for this year was to create a series of eight charcoal drawings that will depict one man and one woman under a starry night sky. This series has the title of Same, but Different. Not only does the short phrase have a personal connection to my childhood, but it also applies to the message I wish to convey with these drawings. A message that while some events may drastically change how we live as a society, the very core ideas and beliefs can be seen staying consistent and steady.


Skye Dorisa Brugler: Land Use Drivers of Nitrate Levels in Crow Creek Watershed Tributary of the Mississippi River

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Advisors: Dr. Kevin Geedey and Dr. Michael Reisner, Senior Inquiry project

Abstract: Crow Creek in Scott County, Iowa, is a tributary of the Mississippi River and its watershed occurs in a gradient of agricultural, mixed, and urban land use. In 2018 and 2019, two hot spots for nitrate were identified in the watershed at established sampling sites, (hot spot 1: mean of 4.21 mg/L and mean 4.76 mg/L, hot spot 2: mean 5.89 mg/L and mean 5.39 mg/L). 

The goal of this project was to look upstream of these two high flux zones and in between them to piece together the origin of the nitrate in order to provide a report to the city on the worst water quality sites in this watershed, as well as to provide guidance about the process of water quality improvement. In the fall of 2020, on Oct. 17 and Nov. 7, 11 urban sites, 12 agricultural sites, and six sites that were approximately an equal combination of both urban and agricultural were sampled. These sites were chosen to capture nitrate levels at streams that are not part of our usual sample network for this watershed. 

Samples from the watershed were taken in acid-washed sample containers, stored on ice, and loaded into a discrete autoanalyzer for colorimetric analysis via the cadmium reduction method. We observed that approximately 50% of the agricultural sites showed a higher nitrate concentration than all the urban sites while 91% of the agricultural sites showed a greater concentration than 90% of the urban sites. We found a statistically significant difference between nitrate concentration in agricultural streams than urban, (ANOVA, 2df, F= 6.628, p<0.005). It was not the case that low-order streams were all elevated in nitrate. First-order agricultural streams were elevated in nitrate compared to urban ones. The results suggest that factors of land use, specifically agricultural land use upstream, explains the flux of nitrate concentrations in the previously identified hot spots.

Beth Kuehnel: Isolating Antibiotic Producing Bacteria From Soil

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Advisor: Dr. Lori Scott

Abstract: The Tiny Earth Project Initiative (Tiny Earth ) is a global student-based research initiative with the goal of finding novel antibiotic producing bacteria in local soil. Their initiative addresses a rising global health concern; antibiotic resistance. The CDC reports more than 2.8 million antibiotic resistant infections occur each year, with approximately 35,000 deaths as a result (CDC, 2021).

According to TEPI, pharmaceutical companies no longer invest in novel antibiotic discovery due to low probability of finding such antibiotics. The TEPI project addresses this concern by recruiting student researchers to carry out individual research, collect data, and submit said data to the worldwide TEPI database. In my project, 71 soil isolates were tested against the tester strains Bacillus subtilis and Erwinia carotovora.

Two of these isolates were further analyzed using standard biochemical tests and then identified as the genus Bacillus and genus Pseudomonas by DNA sequencing of the 16S rRNA gene. Next, the putative antibiotic was extracted from the Pseudomonas isolate. The extract showed enhanced zones of inhibition against the tester strain Bacillus subtilis.

“Biggest Threats and Data.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 2 Mar. 2021,
Tiny Earth, University of Wisconsin System Board of Regents,

Sara Prier: Isolation and Identification of Antibiotic Producing Soil Bacteria: The TEPI Project

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Advisor: Dr. Lori Scott

Abstract: Over the past few decades, the global antibiotic crisis has become a looming threat to the future of healthcare. Through a multitude of factors, such as over-prescription antibiotics and the failure of patients finishing their antibiotic prescriptions, there has been a rise of multi-drug resistant (MDR) bacteria. The Tiny Earth Project Initiative (TEPI) has been working since 2018 to combat this crisis, through the use of student led research projects to discover novel antibiotic-producing soil bacteria.

Out of our original 88 soil isolates, 3 were shown to have strong antibiotic production when tested against Bacillus subtilis and Erwinia carotovora. These isolates were subsequently testing against Staphylococcus epidermidis, Escherichia coli, Acinetobacter baylyi, and Pseudomonas putida. Following colony PCR and DNA sequencing of the 16S rRNA gene, these isolates are predicted to be strains of Pseudomonas. The next step for this project is to perform an organic extraction to identify the type of antibiotics being produced by our isolates.

Haider Ali, Ryan Sorenson: Relationship between BDNF and PGC-1ɑ in the Human Brain: Implications for the Role of Exercise in Parkinson’s Disease and Depression

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Advisor: Dr. Shara Stough

Abstract: It has been established that regular exercise can reduce the risk, and even alter the consequences of a variety of diseases that involve neurodegeneration. Parkinson's disease (PD) is known to cause degeneration of dopaminergic neurons in the substantia nigra, leading to the progressive loss of motor function.

Up to 50% of PD patients experience depression, which is associated with decreased neurogenesis in the hippocampus. Exercise has been shown to increase levels of brain-derived neurotrophic factor (BDNF) which plays a vital role in hippocampal neurogenesis as well as neuroprotection of dopaminergic neurons by decreasing inflammation caused by reactive oxygen species in PD patients.

Pparg coactivator-1-alpha (PGC-1ɑ) is also activated by exercise and reduces inflammation in the brain. Furthermore, researchers have discovered that PGC-1ɑ is downregulated in PD and depression and its overexpression can reduce dopaminergic cell loss.

Therefore, our goal was to investigate whether a relationship exists between BDNF and PGC-1ɑ levels in the healthy brain, which would support the possibility that the pathways interact directly during exercise.

Using a publicly available dataset from the Allen Institute for Brain Science, we conducted a correlational analysis on levels of BDNF and PGC-1ɑ gene expression in the substantia nigra and hippocampus using SPSS statistical software. We found a significant negative correlation between PGC-1ɑ and BDNF expression when both brain areas were included in the analysis, but no correlation when the hippocampus and substantia nigra were analyzed separately. This result was in the opposite direction of our prediction, and may be explained by an inverse relationship between BDNF mRNA and protein levels that has been reported in some studies.

Allisha Ishaque: Isolation and Identification of Putative Antibiotic Producers from Soil

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Advisor: Dr. Lori Scott

Abstract: This study is part of the Tiny Earth Project Initiative (TEPI), a global network of students and teachers working together to isolate potential new antibiotics from soil bacteria. The CDC claims that “antibiotic resistance is one of the biggest public health challenges of our time. Each year in the U.S., at least 2.8 million people get an antibiotic-resistant infection, and more than 35,000 people die.” (

Out of 57 soil isolates from our study, 6 showed antibiotic production when tested against the bacteria Bacillus subtilis and Erwinia carotovora. Using the polymerase chain reaction (PCR) to amplify the 16S rRNA gene, purified PCR products from these 6 strains were sent to the University of Iowa for DNA sequencing. Using online bioinformatics tools, 2 of the six isolates have been identified as Bacillus strains, 1 was identified as an Arthrobacter strain and the last 3 were identified as Streptomyces strains. Biochemical tests were also performed to confirm the identity of the Bacillus isolates. In the next phase of the project, I plan to extract the antibiotics released by these isolates to further study their antibiotic-producing properties.

Matt MacArthur: Amino Acids Crucial to the Function of Pyrroline-5-Carboxylate Reductase in M. ruber

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Advisor: Dr. Lori Scott, Senior Inquiry project

Abstract: The enzyme pyrroline-5-carboxylate (P5CR) catalyzes the last step in the 3-step proline biosynthesis pathway. An ongoing project in Dr. Scott’s lab is investigating the function of P5CR and proline biosynthesis in the microbe Meiothermus ruber (M. ruber), a thermophile found naturally in hot springs. Environmental stress, such a growth at high temperatures, appears to increase proline production as a coping strategy (reviewed in Meena et al., 2019).

The goals of this project are: 1) to determine if we can purify histidine-tagged Pyrroline-5-Carboxylate Reductase (P5CR) using affinity chromatography; and 2) to perform enzyme kinetics to determine if the loss of three adjacent and highly conserved amino acids in P5CR cause a reduction in enzyme activity. For the first step of this project, we confirmed through DNA purification, PCR, and DNA sequencing of the 16S rRNA gene that we are working with the appropriate bacterial strains containing the desired mutation and histidine tag. The next step of the project was studying the growth conditions that upregulate P5CR expression by arabinose induction.

Jacob Wyco: Tracking Residual-Yolk Triglycerides in Hatchling Painted Turtles

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Advisor: Dr. Tim Muir

Abstract: Hatchling painted turtles (Chrysemys picta) spend their first winter inside their natal nests and must survive on maternally derived residual yolk for up to nine months. We investigated the mobilization and usage of residual-yolk energy during the first 33 weeks after hatching by measuring changes in mass and triglyceride content of the yolk, liver, and carcass throughout that period.

We aimed to vary residual yolk mass at hatching in two groups of hatchlings by incubating one group in dry conditions and the other in wet conditions. Our data show that yolk mass significantly decreased over time, but did not differ between incubation conditions. The dry masses of carcass and liver significantly increased in the first two weeks, and gradually decreased thereafter and were also unaffected by incubation conditions.

Triglyceride content of carcass and yolk significantly decreased over time and significantly differed between the two incubation conditions. Yolk triglyceride content fell by 70% in the first two weeks, whereas that of the carcass remained constant until week ten for the dry group and week 33 for the wet group.

Liver triglyceride content for the dry group did not change, whereas for the wet group it significantly increased during the first two weeks and gradually returned to initial levels by week 33. Dry incubation conditions, when compared to wet incubation conditions, resulted in lower liver triglycerides soon after hatching, and lower carcass triglycerides at hatching, indicating that incubation conditions may influence post-hatching triglyceride storage.

Our data suggest that triglycerides are mobilized from the yolk very quickly after hatching and are subsequently stored in the liver and other somatic stores for use until hatchlings emerge in the spring.


Matthew Garcia: Biomimicry - Replicating Chameleon Skin

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Advisor: LeAnn Faidley, Wartburg College

Abstract: Biomimicry is a practice that learns from and mimics the design and strategies used in nature to solve human design problems. We looked into the idea of replicating chameleon skin using an autoclaves method to grow crystals that could replicate the way chameleons change their skin tone.


Ngoc Bui: Discovering Digital Marketing and the Effectiveness of Recruiting International Students

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Advisor: Dr. Choi Hyeong-Gyu and Dr. Lina Zhou, Senior Inquiry project

Abstract: The sole purpose of this research is to discover the most effective digital marketing channels for higher-ed institutions’ niche market - a market of international students. How can a high-school student from Vietnam know about a college/university in the US when he/she is from the other side of the world? I received this question various times when I came to the US as an international student four years ago.

Thanks to the tremendous growth in internet technology and the trends in globalization, many high-school students have been going abroad to pursue higher education. This research focuses on analyzing the marketing strategies colleges and universities are using to recruit international students and explaining how digital marketing can be more effective when it comes to recruiting international students.


Iva Vucic: Experimental Design for Studying Silica Surface Interactions via Infrared Spectroscopy

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Advisor: Dr. Wilmsmeyer

Abstract: Silica surfaces, in conjunction with infrared spectrometry, can be used to study intricate and previously undescribed intermolecular interactions with small molecules. Even today, there are many unanswered questions regarding the fundamental adsorption processes between silica and small molecules.

For large molecules with multiple functional groups, there could be competition between varying highly-electronegative atoms and even aromatic π-electrons when forming hydrogen bonds, which could be defined and described by studying the molecule’s absorption to a silica surface. The work described in this poster involves the development of an experimental setup that utilizes external optics and a low-pressure vacuum chamber to accurately direct an IR beam into a clean sample environment suitable for testing small molecule adsorption onto silica surfaces.

This experimental setup is still under development, and upon completion will be used to efficiently study the characteristics of intermolecular interactions between a silica surface and adsorbed chemicals. This experimental setup could be used for understanding currently undefined fundamental adsorption processes, which could be used in the development of gas sensors for lung cancer and cheaper yet more effective filters for pollution.


Joshua Teets: Economic Development Crisis in Venezuela

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: This video poster presentation will explain the work I have thus far completed in my investigation of the causes and conditions that have led to the economic, political, and social collapse surrounding the Bolivarian Republic of Venezuela. This study primarily focuses on the usage and reinvestment of gains from Venezuela's massive oil deposits, the central governments involvement in oil, regulation and in social programs, and a discussion of the effects that economic policy has had on the country in recent years.

John Kappel: Comparative study between China and India; How economic development affects sporting development

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: A comparative study between China and India; how economic development affects sporting development.

Ruhee Shrestha: How COVID-19 impacts growth and increases inequality in developing countries (with a special focus on South Asia)

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: How COVID-19 impacts growth and increases income inequality in developing countries (with a special focus on South Asia).I would like to look into the global economic inequality faced by marginalized groups of people during COVID-19, and see how sensitive the labor force is sensitive to shut down, larger the informal sector as opposed to developed countries.

Matthew Lampaasona: How Alcohol Consumption Hurts The Developing World

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: The work I will be presenting on will be a deep look into how alcoholic beverages affect developing countries. In particular I will be looking at the affects of alcohol on Brazil. This research will be compared to the research I have already done based on the United States and how the prohibition affected mortality rates.

Thao-Nhi Huynh: Charitable Spending in Developing Countries

Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: Charitable giving has been shown to have a great impact on the economy such as increasing jobs, economic activities, and a vital role in catalyzing growth in communities (National Council of Nonprofits). As these organizations rely on support from people, studying the charitable giving behaviors is crucial.

Previous studies have demonstrated mixed findings regarding the tendency to give (Herzog & Yang, 2017). For example, inconsistent findings have been found regarding the predicting power of gender and race, and volunteering (Roberts, 2019).

Using the data from various sources, I will explore and compare the determinants of charitable giving in developing countries, with an emphasis placed on Vietnam. Possible independent variables include social capital, demographics, education, psychological inclination (happiness), as well as financial resources.

Duy Nguyen: In The Long Run, We Are All Dong

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: An economic analysis of Vietnam's currency - Vietnam Dong. This project aims to bring up a discussion on Vietnam's money supply and currency system, examining the country's key differences as compared to other currencies and forms of exchange rate. In addition, this project offers a critique against mainstream U.S. framing of the Vietnam's economy. Hypothesize on best course of action for Vietnam's economic development regarding it's currency, while acknowledging the forces of international trading and globalization

Thu Ho: The environmental consequences of economic development in Southeast Asia

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: Poor environmental quality is an inescapable presence in many developing countries, causing emerging threats to human health and security. The health effects of pollution can also lead to low productivity, market failures, social conflicts, and surging healthcare costs. Despite these inevitable challenges, minimal resources have been invested in environmental quality improvements in low-income countries due to the lack of information.

Therefore, this project aims to study the root causes of weak environmental security in Southeast Asia, which covers diversified climatic zones and experiences an array of climate change impacts. Since governments in Southeast Asia tend to prioritize economic growth at the expense of environmental quality, these nations are facing enormous risks resulting from climate change, urbanization, water scarcity, overfishing, and pollution.

Without feasible immediate strategies, these nations may encounter several transnational and multilateral environmental consequences. Hence, implementing cost-effective policy and environmental protection measures are crucial steps towards sustainability. This project will also evaluate some ongoing policy approaches that aim to reach the equilibrium between economic growth and improved environmental outcomes.

Jania Gamble: Exploring the Economic Effects of the Trophy Hunting and Ivory Industries in Southern Africa

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: This senior inquiry focuses on the elephant and ivory industries and the various ways elephants are used for profit in the southern region of Africa. Botswana and South Africa have large markets and lots of government policy surrounding trophy hunting. A consistent theme in each country that allows trophy hunting, is that each country needs the industries to be able to sustain their economy.

As the international ban on ivory pushes more and more countries to close down their domestic markets, and animal rights groups push for the banning of trophy hunting, it is important to evaluate the extent to which these countries rely on trophy hunting and ivory trade, and what (if any) industry would be able to replace it. To do this, you must also look into environmental factors, corruption, international and domestic policy that plays into this system.

Alek Jacobs: The impact of COVID-19 on life expectancy in developing countries in the Middle East

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: COVID-19 has greatly changed the way we live our lives. It has also had an impact on period life expectancy. This project will look to compare and explain the decline in period life expectancy in the Middle East during the COVID-19 pandemic.

Hongliang Meng: Bangladesh's railway construction for the country's economic development

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Advisor: Dr. Chris Marmé, Senior Inquiry project

Abstract: I intend to study the impact of Bangladesh’s railway construction on the country’s economic development in my thesis.

The reason for choosing this theme is that I think that the circulation of goods can greatly promote the economic development of a country. Compared with the transportation method, the transportation volume of automobile transportation and air transportation railway transportation is relatively higher and the price is relatively cheap. But the construction of the railway project is undoubtedly expensive and requires a lot of labor and capital.

I previously studied the impact of railways on the United States in the 19th century. However, the United States is now a developed country and Bangladesh is a developing country. Therefore, the methods and timing of railway construction in the two countries are also different due to differences in economic development and policies. I can compare the economic impact of railway construction on the two countries and find out whether railway construction has more economic impact on developing countries or developed countries.

Later, I will also discuss the different economic benefits of Bangladesh’s railway construction in the past and the current railway construction in different periods. I will compare the economic benefits brought about by the construction of the railway in 1970 with the economic benefits brought about by the railway construction in the last ten years.


Autumn Peele: Rib Histology of Edmontosaurus and Triceratops: an Analysis on Suitability for Determining Ontogeny

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Advisor: Dr. Kelsey Arkle, Senior Inquiry project

Abstract: Ornithoscelida, including genera like Triceratops and Edmontosaurus, is a well-studied group in the Dinosauria clade. Lack of well-preserved long bone fossils and research have, however, rendered histological data lacking for multiple species.

This data comes in the form of ontogenetic analysis and is vital in understanding skeletal maturity and growth. Long bones are preferential for histology due to their circumferential shape but are less numerous as skeletal elements, and so are less common than ribs.

To address the lack of ontogenetic information within this group, my senior thesis research focuses on performing histological analysis on Edmontosaurus and Triceratops postcranial fossil material to test if rib histology is suitable for determining ontogeny in these groups.

Ontogeny can be assessed by analyzing microosteological characteristics of the rib thin sections, such as osteocytes, osteons and bone tissue. Key features I will be looking to identify are lines of arrested growth (LAGs) because of their ability to record annual bone growth.

Thin sections of the medial shaft of an Edmontosaurus rib were prepared at the petrographic facility at University of Iowa and ground approximately 70 μm thick. Microscope analysis of slides revealed two possible LAGs. Parallel, continuous lines are present before they are overlain by secondary remodeling that obscures most of the sections. Open channels in the cancellous bone are assumed to be a preemptive stage before transitioning into primary osteons. This, as well as high osteocyte density, is indicative of immature bone. While this individual test was not able to determine age range from lack of LAGs, there is promise that rib histology is a suitable method for establishing ontogenetic age in Ornithoscelidan fossils.

Carson Cerquone: Evaluating Functional Diversity of Marine Mollusk Communities: A case study of Grand Cayman Island

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Advisor: Dr. Kelsey Arkle, Senior Inquiry project

Abstract: The application of diversity measures as a tool for monitoring biotic community health has extensive use in conservation science. Traditional measures of ecosystem health are calculated using taxonomic diversity. While these measures provide important insights into community organization by assessing species richness, evenness, and ranked abundance, they fall short when assessing the functional relationships of individual species.

Without a clear understanding of the roles filled by taxa within a community, it is challenging to predict changes as a result of perturbation. Assessment of functional diversity based on a thorough understanding of the biological roles of the species present allows for more predictive and targeted conservation efforts.

This study aims to construct and test a functional diversity framework using marine mollusks from Grand Cayman Island as a method of determining this community’s overall health and resilience to past and future perturbations. To establish the functional groups, 11 life mode variables: feeding strategy; shell composition; tiering; motility; salinity; depth; substrate, and temperature preference; body size; geographic range, and fossil first appearance data were determined for each identified taxa.

Attributes were recorded using a fuzzy coding method, in which species could reflect a value of 3 (obligatory), 0 (no expression), 1 or 2 (facultative expression). We then used R to calculate a cluster analysis based on Gower distances among all species present. Preliminary results using this method indicate the formation of ~20 functional groups. Further analysis aims to apply our functional framework to species abundance data and quantify important markers like functional redundancy to assess the health of this community.

Joel A Padgett: Spatiotemporal Distribution of Neotectonic Activity in the Araya-Paria Peninsula, Venezuela

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Advisor: Dr. Jenny Arkle, Senior Inquiry project

Abstract: The Araya-Paria Peninsula is a narrow E-W trending metamorphic hinterland exposed between the Caribbean and South American plates along the north coast of Venezuela. The mountain belt is thought to have experienced surface uplift primarily during Miocene oblique collision and is now located along the active dextral El Pilar plate boundary fault zone (EPFZ).

We performed geomorphic analyses on 175 catchments and on the mountain fronts across the peninsula to characterize the spatiotemporal distribution of neotectonic activity in the Araya-Paria Peninsula. Geomorphic indices include the valley width-to-height ratio (V), catchment elongation (E), catchment asymmetry (A), and hypsometric indices (HI) at the catchment scale, and the mountain front sinuosity index for 17 regions (~10 km) along the north coast and the range’s southern flank.

Variations in these geomorphic indices were evaluated in light of lithologic erosivity indices and variations in vegetation and precipitation.  In the eastern study area (Paria Peninsula), high HI values, a nonuniform direction of catchment asymmetry, and V-shaped valleys may indicate a significant control from resistant lithology and uniform south-dipping bedrock.

In the south-central peninsula, planimetric mountain fronts (M < 1.5) and high V values (V > 4) are interpreted to be the result of surface uplift due to active Caribbean-South American plate boundary tectonics. In the western study area (Araya Peninsula), generally low HI (< 0.4), highly sinuous (M > 2) mountain fronts, and regionally low relief (< 400 m), despite relatively resistant bedrock, suggest a highly denuded landscape weakly influenced by active tectonics. These results may reflect how deformation is partitioned by the eastward migration of the Caribbean plate. 

Quintin C Powers: Gastrolith Identification and Replication by Means of Artificial Digestion

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Advisor: Dr. Kelsey Arkle, Senior Inquiry project

Abstract: Gastroliths are important for digestion in many animals, including birds, non-avian dinosaurs, and crocodilians. The digestive system is composed of soft tissues that do not preserve well, but because gastroliths readily preserve, we can use them as a tool to understand the feeding habits of extinct animals like dinosaurs.

Identification of gastroliths is, however, an uncertain practice, since polished non-biological exoliths can resemble their shape and size. Unless they are found in situ, there is no established method for confidently identifying gastroliths.

This study is an attempt to address this issue by establishing key features that can be used to distinguish non-biological exoliths from gastroliths, even when material is not associated with in situ remains, by replicating gastroliths in the lab and comparing their surface features to those of suspected dinosaur gastroliths. Because rocks are exposed to different processes in a digestive tract compared to the external environment, I hypothesize that patterns of surface wear will be significantly different between replicated gastroliths and non-biological exoliths.

To test this hypothesis, we put quartz-rich cobbles, HCl acid, and pepsin in rock tumblers to replicate the chemical conditions of a stomach. In addition to these basic components, the main test group contains pine needles to simulate a potential Jurassic sauropod diet. Three more test groups were run to control for variables: horsetail reeds as a control food, no food to control for the effect of food, and water to control for the stomach environment. Samples were tumbled for around 900 hours, and pictures were taken throughout the process. Additionally, SEM images were taken of the cobble surfaces both before and after tumbling. Results are pending.

Sydney Drier: Lithologic variability and provenance of Pleistocene bedload material in the Meredosia Channel of the Upper Mississippi River

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Advisor: Jeffrey Strasser

Abstract: Pleistocene alluvial deposits of the Upper Mississippi Valley are well known for their lithologic variety, and so, this “river rock” is widely used as landscaping gravel. Few studies have focused on provenance or downstream variations in lithologies of the bedload sediment in the Upper Mississippi River system.

This study analyzed pebble fractions of the Henry Formation sampled from two closely-spaced dredge sites along the upstream edge of the Meredosia Channel of the ancient Mississippi River in northwestern Illinois. The goal of this project is to develop a better understanding of the controls on lithologic variability between different bedload size fractions. Seven lithological categories were identified in pebble counts including: carbonates, sandstone, quartzite, mafic igneous, intermediate igneous, silicic igneous, and lastly miscellaneous quartz and chert.

Grain size fractions for this study included coarse to very coarse pebbles (-5 to -7 Φ), coarse pebbles (-4.9 to -4Φ), and medium pebbles (-3.9 to -3 Φ). Carbonate clasts dominate all pebble fractions at the upstream sample site, suggesting contributions from Silurian bedrock, exposed along the upstream bluffs. The downstream sample site is about 4 km farther away from the bluffs and is situated closer to the middle of the valley. The smaller percentages of carbonates here reflect rapid physical weathering and breakdown of carbonate clasts with downstream transport.

Common lithologies include silicic and mafic igneous clasts, which were transported a minimum distance of ~610 km and ~580 km from their respective upstream bedrock sources. Mafic and silicic components vary little between both sites for size fractions -3.9 to -3Φ and -4.9 to 4Φ, likely reflecting the lithologies’ durability in the fluvial system.

Allison Bandera: Timing and Nature of Surface Uplift of the Northern Range, Trinidad: An Analysis with Knickpoint Indices

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Advisor: Dr. Jenny Arkle, Senior Inquiry project

Abstract: Fluvial geomorphology can be a useful record of tectonic activity. This study analyzes the spatial and temporal distribution of knickpoints from streams that drain the Northern Range, on the island of Trinidad. The Northern Range is bound to the north by the Caribbean Sea and is located ~30 km north of the active southeast Caribbean-South American dextral plate boundary.

Recent studies suggest that the Northern Range has been tectonically active in the Quaternary and is titled east-side up. To better constrain the distribution, timing, and rates of recent surface uplift and subsidence, stream profiles and knickpoints were analyzed from 44 catchments.

Preliminary results yield knickpoints that are consistently located at ~50 and ~200 meters in elevation across the Northern Range. Knickpoints are more prevalent in the east, yet normalized steepness indices (ksn) are higher in the west. Two representative catchments, one from the west and one from the east, were analyzed for lithology.

We identified and mapped constructional (tufa) knickzones, and then focus our analysis on erosional knickpoints. Within the two western and eastern catchments, tributary knickpoints that are not associated with lithologic control are localized at similar elevations around the trunk stream. In the west, the stream profile is concave and the 200 m elevation knickpoints separate steep upper channel reaches (ksn > 250) from shallow lower channel reaches (ksn < 45). In contrast, the eastern stream profile is convex and the 200 m elevation knickpoints separate upper and lower channel reaches with similarly low steepness (ksn < 20–10).

We interpret these spatial patterns of knickpoints as transient landforms caused by a drop in base level either due to range-wide tectonic tilting or sea-level fall.