Student Research Abstracts

Below, read abstracts from sustainability-themed student research projects. These projects were presented at the Inquiry at UST poster session on Tuesday, October 4, 2016.

Assessing a Novel, Financially Sustainable Farmers Market Model for Lower-Income Urban Neighborhoods

Research by: Mackenzie Burke
Faculty mentor: Dr. Adam Kay

Many low-income neighborhoods in North Minneapolis identify as food insecure.  Oftentimes, attempts to make fresh produce more accessible and affordable in low-income urban neighborhoods are short lived because they rely on grants government agencies. A sustainable approach to addressing food insecurity is needed within the scope of public health as well as for greater society.

This research project explored a model for creating financially viable farm stands in lower-income urban neighborhoods. The study also explored whether sidewalk farm stands in lower-income urban neighborhoods provide benefits to corner stores that partner in hosting the stands.

Eight corner stores in North Minneapolis who have pre-existing relationships with community partner, BrightSide Produce, participated. Five corner stores hosted weekly farm stands while three corner stores served as control stores. Each week, one local youth and one university student volunteer hosted a farm stand outside of a corner store for three hours. The stand offered a diverse mix of conventional and local produce.

Remaining produce was sold in $10 shares to local neighborhoods. Each week, members picked up their produce bags at a central location. This guaranteed all produce was sold and youth hosts were able to receive a fair wage for their work at the stands.

Assessing Effectiveness of a Technique in Removal of Polycyclic Musks From Wastewater

Research by: Sarah Beck
Faculty mentor: Dr. Kris Wammer

In recent decades, polycyclic musks (PCMs) have become an essential component of many household materials such as detergents and personal care products. Due to their ability to fix certain fragrances by means of slowing the release of volatiles, they have become widely produced compounds. Unfortunately, new studies have shown that these chemicals are becoming more present in natural Minnesota water sources. Furthermore, other studies have seen that certain polycyclic musks display toxic potential toward aquatic life. These two factors combined make this a topic of high interest to conduct additional research. It is proposed that the systems implemented in wastewater treatment plants (WWTPs) are not adequate enough to completely remove PCMs from wastewater before releasing it back into rivers and lakes. In this research, we will eventually primarily focus on UV light disinfection methods using the two most used PCMs - galaxolide and tonalide. Using a 254 nm germicidal UV-C lamp, our goal will be to replicate the type of light PCMs would encounter in a WWTP and determine the ideal intensity required to sufficiently eliminate such PCMs from the water. Our initial work this summer, however, focused on simulated sunlight using a Suntest CPS+ to replicate the type of light present in the environment. Throughout the summer, we monitored how quickly our PCMs degraded in certain light intensities as well as observed the different photoproducts that grew in throughout photolysis. At the conclusion of the summer, it was determined that both PCMs produce several different photoproducts under simulated sunlight. Also, it was found that tonalide degrades much more readily than galaxolide. In the future, we hope to replicate these experiments with the UV light photoreactor as well as perform various toxicity assays on both photolyzed and unphotolyzed samples.

Can Addition of Disinfection Treatment (UV Radiation or Chlorination) to Conventional Wastewater Treatment Process Reduce Toxicity Associated with Endocrine Disrupting Chemicals?

Research by: Lily Ward
Faculty Mentor: Dr. Dalma Martinovic

Endocrine disrupting chemicals (EDCs) are a group of contaminants of emerging concern commonly found in wastewater treatment plant (WWTP) effluent. EDCs alter normal hormonal functioning in organisms, sometimes resulting in reduced reproductive success. WWTPs tend to be sites of concentration of EDCs, as they receive large amounts of inflow of EDC- containing domestic waste. Effluent is typically discharged into larger bodies of water, resulting in urban waterways with high volumes of WWTP effluent. Considering that EDCs are not completely broken down during the treatment process, and that they are toxic to aquatic life at the extremely low concentrations found in WWTP effluents, we can conclude that EDCs pose a significant threat to the aquatic ecosystems that receive a high volume of effluent from WWTPs.

The O'Brien and Calumet Wastewater Reclamation Plants, two WWTPs in Chicago, implemented UV radiation and chlorination treatments(respectively) following public pressure to improve disinfection of effluent. The Metropolitan Water Reclamation District of Greater Chicago (MWRD), hoped that the added treatments would not only remove pathogens, but oxidize EDCs into less environmentally harmful products. However, in order for EDCs to be completely oxidized, UV radiation needs to be strong and followed by oxidation, which is not how thenew UV and chlorination upgrades treat the effluent. This may be problematic because incomplete oxidation of EDCs can produce toxic metabolites, which are sometimes more endocrine disrupting than their parent compounds. Furthermore, chlorination has been shown to increase estrogenic activity of certain EDCs, such as bisphenol A. The uncertainties surrounding the possible impacts of these infrastructural changes necessitated analyzing effluent for endocrine disrupting activity after undergoing the UV or chlorination treatment.

In order to characterize the impacts of UV and chlorination treatment on the EDC loads in the effluent of the Chicago O’Brien and Calumet WWTPs, we used biological assays to assess whether the endocrine toxicity of the WWTPs effluent was reduced or enhanced by these added treatments.For information on what specific chemicals may be responsible for the endocrine disruption, I referenced a paper by Larry B. Barber (et al.) that characterized biologically active organic contaminants in the North Shore Channel of the Chicago River.

Compost Tea and the Effects of Soil Microbes on Urban-Grown Vegetable

Research by: Marianne Sciamanda
Faculty mentor: Dr. Adam Kay

Urban agriculture has risen as a solution to providing food for a rapidly increasing world population. Practices that increase yield are necessary to maximize the benefits of crops grown in urban, and often small, agricultural spaces. Compost tea has emerged as a method to increase plant growth by essentially acting as liquid compost packed with beneficial microbes. To test the effectiveness of compost tea, as well as study the underlying microbial mechanisms of it, I conducted an experiment. Four treatments: dry compost, compost tea, a combination of dry compost and compost tea, and a control with no application, were tested in raised beds. The yield of each identically-planted bed, as well as the microbial content of the soil/compost, was tested. Compost tea application led to highest average microbial content, however, dry compost plots had the highest yield, which suggests potentially adverse effects of compost tea and the microbes it adds to soil.

Direct Photolysis and Product to Parent Reversion of the Steroid Dienogest

Research by: Madeline K. Hankard
Faculty mentor: Dr. Kristine H. Wammer

Dienogest is a progestin that is used in combination with other molecules for hormonal contraception (sold under trade name Natazia ®) and by itself to treat endometriosis.  Dienogest, like many other pharmaceuticals, is not fully metabolized in the body, is excreted, and ends up in freshwater environments. When dienogest reaches the environment, it is exposed to sunlight and photodegrades into photoproducts. Interestingly, during dark conditions, the photoproducts revert back to the parent molecule. We have found that dienogest degrades slower in acidic conditions than basic conditions. Regeneration is near instantaneous in acidic conditions, but dienogest regenerates to the greatest extent in pH 5. Based on NMR data that comes from collaborators at the University of Iowa, it is suspected that two photoproducts have an aromatic A ring and are therefore likely biologically active. To confirm and quantify biologic activity, we are collaborating with the Martinovic lab of the University of St. Thomas Biology department to run estrogen assays. A preliminary assay shows measurable estrogenic activity for both dienogest and photoproducts, but further assays are necessary.

Drastic Sedimentation Changes in MN Watershed Post-European Settlement

Research by: Samuel Duncanson & Gabrielle Houle
Faculty mentor: Dr. Kevin Theissen

The Comfort Lake-Forest Lake Watershed District encompasses lakes located in both Chisago and Washington County, MN. Several of these lakes were deemed impaired, in part due to higher than recommended phosphorus levels. Three of these impaired bodies: Shields, Comfort, and Moody lakes, are being considered for remediation and long-term management. Before such steps are taken, however, an understanding of the lakes historical conditions needs to considered. Overlapping sediment cores were collected in February 2016 from each lake. The cores underwent several geochemical analyses, including loss on ignition (LOI), magnetic susceptibility, x- ray fluorescence (XRF), and 210-Pb age dating.

Results will focus on LOI and XRF data from the 274cm Shields Lake core. Shields Lake is particularly impaired, with monitored total phosphorus concentrations around 336 μg/l.

LOI results from Shields Lake show an increase from 48% to 73% (dry weight) in deposited organic material occurring around 142cm sediment depth. Shields XRF results show a significant rise then fall in concentrations of Fe and Mn occurring between 156- 200cm. In the same interval, K and Ti concentrations rise.

These results reflect environmental changes that have occurred around Shields Lake within the 274cm sediment interval. LOI data indicates either an increase in the amount of biologic material being deposited into the lake and/or decreases in the amount of land-based material depositing. Although interpretations of XRF data on Mn and Fe are influenced by multiple factors such as redox conditions and weathering + erosion, their spikes in concentration are more likely increases in the latter, or a possible different sediment source. The rise in K and Ti concentration after their brief decline is also suggestive of an increase in terrestrial material, triggered from a possible erosional increase near the lake.

These changes in the lake sediment are likely related to land-use changes caused by European settlement.

Exploration of Menthol as a Renewable Feedstock for Polymer Synthesis

Research by: Nick Hayes
Faculty mentor: Dr. Eric H. Fort

Society today has a huge dependency on plastic; we use it every day in bottles, bags, and various other forms. The majority of plastics that are produced each year come from petroleum. The problem is that someday there will not be any petroleum left, and we will still need plastic. The goal of our research is to find a renewable source to make plastic. Specifically, we want to find out if Menthol (derived from mint leaves) can be used to create a stable plastic. The first step of our research is converting Menthol into a new target molecule. This molecule is much more likely to polymerize and form plastic. Once this step is completed, we will add a catalyst in order to expedite the new molecule to form plastic. The more we understand about how plastics are made using plant derived feedstocks, the closer we will be to finding a renewable source to make plastic.

Initial Effects of Assisted Colonization on the Survival and Growth of Oak Seedlings in a Restored Forest Ecosystem (South Washington Oaks Project)

Research by: Rachael HeierFaculty mentor: Dr. Simon K. Emms

Increasing carbon emissions and other pollution have caused climate change to become an ever growing threat to this world and those that inhabit it. The changing climate could pose a substantial risk to biodiversity, as environmental effects cause native species that were once fit for an environment to be no longer suited for it.  Any species that can’t adapt quickly to the changing environments, mainly those unable to swiftly migrate or with long generation spans that prevent rapid adaptation, are at risk of extinction as the world grows warmer.  Integrated conservation efforts have started to develop to help mitigate these issues, one of these new techniques being assisted colonization.  In the fall of 2015, approximately 900 oak seedlings of two different ecotypes, either native to a Twin Cities location or from a location in Iowa, were planted at the South Washington Oaks Project in Woodbury and Cottage Grove, MN.  In this long-term study, the two ecotypes will be compared in order to judge the effectiveness of assisted colonization as a conservation strategy for the restoration of a forest ecosystem. This past summer of 2016, we took measurements of the first year of growth in the seedlings, including plant fate, survival, and physical aspects such as stem diameter, old, new and total growth heights, number of live stems, number of leaves, and average leaf area. Here we compare and analyze the data from the initial year of the project and use it to determine a baseline for the future data collected that will allow for a conclusion on whether or not assisted colonization can be a viable option for future restoration projects.

Investigating the Diversity of Antibiotic Resistance Genes in Wastewater Bacteria Exposed to Triclosan

Research by: Bridget McGivern
Faculty mentor: Dr. Justin Donato

Many household products, such as toothpastes and hand soaps, contain the antibacterial agent triclosan. When these products are used, triclosan washes down the drain and ends up in the municipal wastewater treatment system, where activated sludge bacteria are exposed to it. The goal of this project is to assess the impact of exposure to sub-lethal doses of triclosan on the antibiotic resistance profiles of bacteria in a simulated wastewater treatment system. Samples of activated sludge bacteria were obtained from a full-scale treatment facility. Bacterial cultures were prepared from this activated sludge, and grown in triplicate in a synthetic wastewater medium with triclosan concentrations of 0, 1, 5 or 15 µg/L. After seven weeks of growth, fosmid libraries were constructed from each culture. Antibiotic selection was carried out on Luria Bertani agar plates supplemented with antibiotics from the major classes. Unique resistant clones were identified, and their antibiotic resistance profiles were quantified through minimum inhibitory concentration (MIC) assays. At present, 29 resistant clones have been isolated from various libraries. These clones represent resistance to six of the thirteen antibiotics that were tested. Of these clones, two are resistant to multiple antibiotics: one is resistant to different β-lactam antibiotics, while the other is resistant to carbenicillin and rifampicin. Some preliminary sequencing has been done in order to determine the mechanism of resistance possessed by the clones, but more extensive analysis needs to be done before any conclusions can be drawn.

Quantifying Cultivatable Antibiotic-Resistant Bacteria in Minnesota Drinking Water

Research by: Carlee Heiling
Faculty mentor: Dr. Kristine Wammer

In recent years, there has been a growing concern regarding the capability of bacteria to become resistant to antibiotics, and the environment is one possible route for propagation of this resistance. In this study, our particular focus was potential impacts associated with drinking water. The specific goal of this study was to determine the levels of antibiotic resistance in St. Paul and Minneapolis tap water. About 1500 L of tap water was filtered through a AsahiKASEI hemodialyzer membrane and the bacteria were subsequently backflushed from the membrane. The bacteria were grown on R2A or iso-sensistest broth (ISB) media amended with high and low concentrations of five different antibiotics and incubated at room temperature. The cultivatable antibiotic-resistant bacteria from these tap water samples were then observed and compared to the antibiotic resistance genes quantified from earlier samples. The Minneapolis sample had more bacteria that exhibited more antibiotic-resistance-like behavior than St. Paul’s for all but one antibiotic, which correlates well with the genetic data previously collected. However, only one sample from each site has been collected and successfully analyzed thus far, so more samples and data are needed to confirm the results.

Stable Isotopes Indicate Zebra Mussels (Dresseina polymorpha)Increase Dependence of Lake Food Webs on Littoral Energy Sources

Research by: Ryan TrappFaculty mentor: Dr. Kyle Zimmer

The influence of zebra mussels (Dreissena polymorpha) on reducing phytoplankton abundance is well known, but their impact on overall energy flow in deep, mesotrophic lakes is less clear.  We assessed impacts of zebra mussels on energy flow by comparing two Minnesota lakes: Lake Carlos has a dense population of zebra mussels, while upstream Lake Ida was free of zebra mussels until 2014 and densities are still extremely low.  We used the stable isotope 13C to assess patterns of energy flow as δ13C values are lower in organisms supported by phytoplankton production relative to organisms supported by littoral energy sources such as periphyton and benthic algae.  We sampled 13C in the tissue of multiple species in each lake to quantify energy sources for the overall food web.  We analyzed eight taxonomic groups for this analysis (three fish species, five invertebrate groups), and calculated the difference in δ13C between each taxonomic group and filter-feeding mussels in each lake (hereafter corrected δ13C).  Mussels rely on phytoplankton as a primary energy source, so larger corrected 13C values in our eight taxonomic groups would indicate greater reliance on littoral energy sources. Results showed corrected δ13C values differed between Lake Carlos and Lake Ida for seven of the eight taxonomic groups, and all seven groups had higher corrected δ13C values in Lake Carlos.  The presence of widespread, higher corrected 13C values in Lake Carlos indicate a greater reliance on littoral energy sources relative to the Lake Ida food web, likely driven by high zebra mussel densities reducing phytoplankton abundance. If littoral and benthic production do not compensate for reduced pelagic primary production, overall availability of energy to native secondary consumers and fish may be lower in Lake Carlos compared to Lake Ida. Increased importance of littoral energy sources could also cause shifts in invertebrate and fish communities towards species better adapted to littoral niches.

Stable Isotopes Reveal Niche Separation Among Three Piscivores in a Northern Mesotrophic Lake

Research by: Zachary George
Faculty mentor: Dr. Kyle Zimmer

The piscivorous Muskellunge (Esox masquinongy), Northern Pike (Esox lucius), and Walleye (Sander vitreus) have strong influences on trophic structure and energy flow in North American lakes.  All three species are popular gamefish with both recreational and economic value, often coexisting in individual lakes either naturally or through stocking efforts.  Given the high degree of piscivory in all three species, there is high potential for interspecific competition and niche overlap.  However, despite their ecological and economic importance, the degree of niche overlap among these three species is poorly known.  We assessed niche overlap by measuring the stable isotopes 13C and 15N in Walleye, Muskellunge, Northern Pike, and their potential prey fish in Elk Lake, Minnesota.  Results indicated three general groups of prey fish based on δ15N and δ13C levels.  Cisco (Coregonus artedi) had high δ15N and low δ13C due to its deep-water, pelagic niche. Mixed-diet fish had high δ15N due to higher levels of piscivory and also high δ13C due to its more littoral niche. Planktivorous had low δ15N from feeding on aquatic invertebrates and high δ13C due to their littoral niche.  The three piscivore species we evaluated appeared to have significantly different diets and niches, each focusing to a greater extent on one of the three groups of prey fish.  Overall, Muskellunge had significantly lower δ13C than both Northern Pike and Walleye, while Northern Pike had significantly lower δ15N compared to Muskellunge and Walleye.  This indicates Muskellunge prey more heavily on pelagic Cisco and Walleye feed more heavily on mixed-diet fish, while Northern Pike feed on a mix of mixed-diet and planktivorous fish.  Our results indicate the response of Walleye, Northern Pike, and Muskellunge to changes in prey fish abundance will depend on the specific species of prey fish in lakes.  Of particular concern is the reliance of Muskellunge on Cisco, as Cisco populations are threatened by eutrophication and climate change.  Our results indicate Muskellunge would be impacted most by reduced abundance of Cisco, potentially forcing Muskellunge to alter their niche and compete more directly with either Walleye or Northern Pike.

Understanding Carbon Emissions from Prairie Pothole Region Wetlands

Research by: Katie Hoffmann
Faculty mentor: Dr. Leah Domine

This project was aimed to gain understanding in methane flux on wetlands in the Prairie Pothole Region. Wetlands are a large source of methane to the atmosphere, and evidence from this investigation yields important data on the flux magnitudes and the source of carbon, which is largely unknown in this region. The project was formulated to have several components – to quantify methane efflux from three wetlands within the Prairie Pothole Region, analyze the variability of methane flux from each, and determine the source of carbon being respired by the system. Floating chambers were utilized over four field deployments throughout the summer to estimate methane efflux at multiple locations from the lakes. A rarefaction analysis will be done to determine the number of sites on a wetland needed to be sampled in order to obtain an accurate methane efflux estimation, and the identification of the carbon source will be done through Accelerator Mass Spectrometry (AMS). The algae-dominated lake had the highest magnitudes of methane fluxes, while the submerged plant-dominated lake was significantly less, and the microalgae-dominated lake was the lowest. The range of average methane flux for the summer from the algae-dominated lake was 161-475 mg m-2 d-1, the submerged plant was 7-109 mg m-2 d-1, and the macroalgae was 3-103 mg m-2 d-1. Overall, the mid-summer sampling dates had the largest magnitudes of fluxes than the later sampling dates, which was true for all three different wetlands. The rarefaction analysis would allow a number of sites required to be monitored to be determined, which would improve sampling efficiency and maximize time. The radiocarbon analysis identifies the age of the carbon, meaning it has the potential to identify a new source of carbon – if old carbon is identified, it is likely that a terrestrial source of carbon is augmenting the system.

Variation in the Rate of Photolysis of the Steroid Gestrinone in the Presence of Sodium Azide

Research by: Jessie O'Brien
Faculty mentor: Dr. Kristine Wammer

The widespread use of steroids by humans and livestock has raised concerns about their presence in the environment. Because steroids are not fully metabolized, various concentrations of biologically active steroids can be found in surface water.

Many of these steroids are classified as dienones (like gestrinone) and trienones. These structures allow the steroids to absorb sunlight and break down into different photoproducts by the process of direct photolysis. As steroids enter the environment they may also interact with a series of reactive species that additionally contribute to the steroids’ photodegradation. One fundamental class of reactions that occurs in our environment is nucleophilic attack. In order to better understand the environmental fate of steroids, it is necessary to understand the role nucleophiles have on photolysis in various conditions. In this study, we focus on the steroid gestrinone in the presence of the electron rich nucleophile sodium azide. Gestrinone is a synthetic progestin that is used to treat endometriosis. It is sold under the trade name Dimetriose®. The objective of this study was to examine the rate of photolysis of the steroid gestrinone as well as its photoproducts in the presence of different concentrations of sodium azide at pH 5 and 9. It was found that in the presence of sodium azide gestrinone is transformed into two different photoproducts during photolysis at both pH 5.00 and 9.00. The rate of photodegradation of gestrinone increases as the concentration of sodium azide increases at pH 5.00 while at pH 9.00 the concentration of sodium azide has little effect on the rate of photodegradation of gestrinone.