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B&W Notebook: highlighting student research

Beneficial microbes in contaminated aquifers – Chris Kasanke

Hi! My name is Chris Kasanke. I'm a Ph. D. student working with Dr. Mary Beth Leigh in the Department of Biology and Wildlife studying the microbial degradation of sulfolane, an emerging environmental contaminant. My research involves determining if microorganisms indigenous to sulfolane-contaminated groundwater in the subarctic can biodegrade sulfolane. We’ve found native microbes that degrade sulfolane and have identified environmental factors that limit their activity. Moving forward, we hope to identify these sulfolane degraders and determine their prevalence throughout the contaminated site.
Photo by Shawnee Gowan

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Beneficial microbes in contaminated aquifers – Chris Kasanke

The site I'm studying is located in the city of North Pole, Alaska and is one of the largest contaminated groundwater plumes in the state. The source of the contaminant is an oil refinery where sulfolane was used for many years in the refining process. Although the highest groundwater concentrations of sulfolane are found on refinery property, it has also been detected in hundreds of residential wells outside the refinery property. The owners of the refinery are currently providing clean drinking water for affected households. In the picture, the red line approximates the sulfolane-contaminated area.
Photo by Alaska Department of Environmental Conservation (map)

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Beneficial microbes in contaminated aquifers – Chris Kasanke

Our research team collects samples, which consist of aquifer sediment and groundwater, from within the region of sulfolane contamination. We’ve found the aquifer to be home to an active and diverse microbial community. Research has shown that for most environmental contaminants, it's generally more effective to stimulate indigenous microorganisms to degrade pollutants than to release lab-grown "super bugs" into the environment. For this reason, we're working to determine if the aquifer already has sulfolane-degrading microbes present, and then to determine what might accelerate their activity.
Photo by Mary Beth Leigh

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Beneficial microbes in contaminated aquifers – Chris Kasanke

The samples are then taken back to the lab to be used for controlled microcosm studies. We combine the soil and groundwater with sulfolane and then monitor the sulfolane concentration over time to test for biodegradation. To extract the sulfolane we use an organic solvent which has a high affinity for sulfolane and does not mix with water. We collect the solvent, which now contains the sulfolane, and then quantify it using gas chromatography coupled to mass spectrometry (GC/MS). The yellow arrow shows the solvent-water interface, with the solvent on the bottom and water on the top.
Photo by Shawnee Gowan

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Beneficial microbes in contaminated aquifers – Chris Kasanke

We sometimes add other amendments to the microcosms in an attempt to stimulate biodegradation. It's well documented that, much like plants, microbes can be stimulated by the addition of a nutrient solution. One unconventional nutrient solution we found to stimulate sulfolane biodegradation was the settlings from beer fermentation obtained from the Silver Gulch Brewery in Fox, Alaska. This is an image taken using a transmission electron microscope from one such study. The material stuck to these bacterial cells is the fermentation settlings.
Photo by Chris Kasanke

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Graduate Student Research

There are over 90 graduate students enrolled in the Biology and Wildlife program, studying and conducting research in a wide range of fields, including (but not limited to) human-wildlife interactions, insect population ecology and taxonomy, ecosystem ecology and biogeochemistry, the neurobiology of breathing, bioremediation, the evolution of mammals, climate change effects on the boreal forest, insect-plant interactions, virus-host cell interactions, and health and nutrition of Native Alaskans, to name a few. This notebook highlights just a few of the impressive research projects conducted by our students. Enjoy!

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