VIRTUAL STUDENT SCHOLARS SYMPOSIUM 2020 PRESENTATIONS

Environmental Sciences - Poster Presentations

High School Division

Developing Pesticide Resistance to Acetylcholinesterase Inhibitors in D. pulex
Jordan R Harrow, Episcopal School of Jacksonville

This investigation worked to mitigate the negative effects of pesticide run-off on non-target organisms by generating pesticide resistance to acetylcholinesterase inhibitors, a classification of pesticides, in Daphnia pulex. D. pulex are a common species of zooplankton present in most freshwater environments and are essential components of freshwater ecosystems. They can naturally develop pesticide resistance and can act as buffers to the effects of pesticides for aquatic organisms in higher trophic levels. Resistance was created in the lab through gradual exposure of D. pulex to the LD50 concentration of malathion, an acetylcholinesterase inhibitor, over 54 days, which is approximately 6 generations. The resistance of D. pulex was tested through mortality rates of previously exposed D. pulex in the presence of an LD75 concentration as compared to the mortality rates of sensitive D. pulex. It was hypothesized that the previously exposed D. pulex would have higher survival rates than the sensitive D. pulex when exposed to the LD75 of malathion. After the second exposure, results showed that the sensitive D. pulex had an 80% higher mortality rate than the previously exposed D. pulex. Between the previously exposed D. pulex and the sensitive D. pulex, there was a difference of 80% as compared to the control. The data supported the hypothesis and suggests that lab-engineered pesticide resistance was generated in D. pulex, meaning this process could be repeated on a larger scale to mass produce resistant D. pulex that could be introduced into affected environments and decrease mortality rates of non-target freshwater organisms.

Undergraduate Division

Identification of Pseudomonas species that Aid in the Colonization and Biodegradation of Environmental Microplastics
Reynaldo R Bujan, Phoenix College

Recent studies have reported that drinking water around the world contains microplastics, which are small pieces of plastic (<5 mm). It is estimated that 94.4% of tap water in the U.S. contains plastic fibers that can be cytotoxic. Microplastics have been found to bioaccumulate pollutants. Currently, microplastics are not being removed from water, even in wastewater treatment plants. This is an emerging issue that will require the design of strategies to reduce microplastic contamination in our recreational and drinking water supply. One proposed solution is the use of microbes to aid in the biodegradation of microplastics. Studies have demonstrated that Pseudomonas species (P. putida and P. fluorescens) grow on polyvinyl chloride (PVC), while P. stutzeri has been found to grow on hydroxybutyrate. In addition to colonizing microplastics, studies have shown that Pseudomonas species may play a role in the decomposition of plastics such as polyvinyl alcohol, polypropylene, and polyethylene. The purpose of this project was to determine if P. stutzeri is capable of colonizing and biodegrading polyvinyl chloride (PVC), low-density polyethylene (LPDE), and polypropylene (PP). To achieve this goal, P. stutzeri was co-incubated with the three plastic types for 7 to 180 days. The co-incubated microplastics were then placed on Pseudomonas Isolation Agar and analyzed by Scanning Electron Microscope (SEM) to confirm colonization by P. stutzeri. Preliminary SEM and FTIR data show biodegradation of PVC, LDPE, and PP microplastics. The findings of this study have implications for the bioremediation of microplastic contamination in environmental water and soil samples.

Colonization and Time-Dependent Biodegradation of Microplastics by Pseudomonas aeruginosa
Roberto Martinez, Phoenix College

Recent studies have reported that drinking water around the world contains microplastics, which are small pieces of plastic (<5 mm). An estimated 94.4% of tap water in the U.S. contains plastic fibers that can be cytotoxic. Microplastics have been found to absorb pollutants that are resistant to degradation and that bioaccumulate pollutants. Currently, microplastics are not removed from water, even in wastewater treatment plants. This is an emerging issue that requires the design of strategies to reduce microplastic contamination in recreational and drinking water supplies. One proposed solution is the use of microbes to aid in the biodegradation of microplastics. Studies have demonstrated that Pseudomonas species (P. putida and P. fluorescens) grow on polyvinyl chloride (PVC), while P. stutzeri was found to grow on hydroxybutyrate. In addition to colonizing microplastics, Pseudomonas species may play a role in the decomposition of plastics such as polyvinyl alcohol, polypropylene, and polyethylene. The purpose of this project was to determine if P. aeruginosa is capable of colonizing and biodegrading polyvinyl chloride (PVC), low-density polyethylene (LPDE), and polypropylene (PP). To achieve this goal, P. aeruginosa was co-incubated with the three plastic types for 7 to 180 days. The co-incubated microplastics were then placed on Pseudomonas Isolation Agar and analyzed by Scanning Electron Microscope (SEM) to confirm colonization by P. aeruginosa. Preliminary SEM and FTIR data show biodegradation of PVC, LDPE, and PP microplastics. The findings of this study have implications for the bioremediation of microplastic contamination in environmental water and soil samples.

Graduate Division

Assessment of satellite data and real-time data for monitoring harmful algal blooms in Oregon lakes
Victoria E Avalos, Portland State University

Freshwater harmful algal blooms, dominated by toxin producing cyanobacteria, can be detrimental to wildlife, pets and human health. New tools, such as satellite derived data, may allow interested parties to monitor lakes for algal blooms without in situ monitoring. This project compares satellite derived cyanobacteria abundance (cells per mL) from the Cyanobacteria Assessment Network (CyAN) mobile application (developed by the U.S. EPA) with estimates of cyanobacteria abundance from field measurements Odell and Crescent Lakes in Oregon, USA. These neighboring lakes have similar natural histories; however, Odell Lake has a history of harmful algal blooms whereas Crescent Lake does not. Grab samples were taken from Odell Lake on a weekly from June through September 2019. Cell counts were generated via microscopy were analyzed against the CyAN derived cell counts. Cyanobacteria abundances quantified via microscopy were compared to the satellite derived abundances produced by CyAN. Preliminary results show that CyAN recorded peak cyanobacteria abundance at 1,106,624 cells/mL on July 23rd and grab samples recorded Dolichospermum as the dominant algal species. On this date, chlorophyll-a (52.4 μg/L), nitrogen (1.75 mg/L) and total phosphorus (0.08 mg/L) also reached maximum concentrations. Upon further research, we hope to find CyAN to be a reliable measurement of cell counts, which would further advocate for its use in Oregon as a free monitoring tool for concerned parties that do not have the resources to perform intensive and costly in situ monitoring.

VIRTUAL STUDENT SCHOLARS SYMPOSIUM 2020 PRESENTATIONS

Environmental Sciences - Poster Presentations

High School Division

Undergraduate Division

Graduate Division

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