Judy Yang Receives NSF CAREER Award

Judy Yang is an Assistant Professor in the Department of Civil, Environmental, and Geo- Engineering and Saint Anthony Falls Laboratory at the University of Minnesota. Her research in water resources focuses on transport of fluids, particles, bacteria, and chemicals in the environment. She received a prestigious CAREER Award from the National Science Foundation (NSF), an award given to outstanding junior faculty who exemplify the role of teacher-scholar, excelling at and integrating both research and education. 

…tiny organisms can play a pivotal role
in many pressing environmental issues…

Yang’s NSF CAREER Award project is titled “Predicting Biofilm-Bound Sediment Dynamics Through Multiscale Experiments.” It will be funded for $653,000 over five years. The research will shed light on the fundamental mechanisms that govern the interactions among microbes, fluid, and particulates. The results of the research will guide erosion restoration projects for coasts and rivers, and will support prediction and control of the spread of biofilm-bound particulate contaminants.

On receiving the award, Yang commented, “I will use this grant to support a couple of graduate students and many undergraduate students. Together, we will develop cutting-edge technology to reveal how tiny organisms can play a pivotal role in many pressing environmental issues, including coastal and riverine erosion and contaminant transport. My group is in a unique position to pioneer this new research direction because we are one of the few groups in the world that have expertise in both microfluidics and flume experiments and knowledge in both microbiology and fluid mechanics.”

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RESEARCH ABSTRACT:  Sediment transport is a key process controlling coastal and riverine erosion, which cost the U.S. billions of dollars per year. Most natural sediment, such as mud and fine sand, inevitably harbors microbial biofilms. Biofilms have been shown to alter the threshold and rate of sediment transport by up to 40-fold. However, predictive sediment transport equations that account for the impacts of biofilms are lacking. A key challenge in developing such predictive equations is that the transport of sediment at macroscale (> 1 m) is controlled by biofilms at micro (10^-6 to 10^-3 m) to mesoscale (10^-3 to 10^-1 m). Yang’s study aims to combine micro- to mesoscale flow-cell and imaging technology with macroscale flume experiments to quantify the impacts of micro- to mesoscale biofilms on macroscale sediment transport. The team aims to develop predictive equations for biofilm-bound sediment transport. The results of the study will help improve predictions of coastal and riverine erosion, which will guide future coastal and riverine restoration projects, and support better predictions and control of the spread of biofilm-bound particulate contaminants. In addition, hands-on, multiscale educational activities based on the proposed research will be developed and integrated into teaching, mentoring, public outreach and K12 education. These activities will introduce the essence of the research to a diverse range of young learners, including female and Native American students.

The goals of the proposed research are to (1) quantify the impacts of sediment size and hydrodynamic conditions on the properties of micro- to mesoscale biofilms on sediment surfaces; (2) predict the macroscale transport of suspended microscale biofilm-sediment aggregates; and (3) predict the onset of bedload transport for sediment covered with mesoscale biofilm mats. Systematically controlled experiments with confocal microscopic imaging with submicron resolution will be conducted in microfluidic flow cells to visualize and quantify the development of micro- to mesoscale biofilms on sediment surfaces and the formation of biofilm-sediment aggregates. Flume experiments combined with digital imaging, tensile tests, rheometer measurements, hydrodynamic measurements, and topographic measurements will be conducted to quantify the impacts of biofilms with varying morphological and rheological properties on macroscale sediment transport. The results from both microfluidic and flume experiments will be used to develop predictive equations for the transport of suspended biofilm-sediment aggregates and biofilm mat-covered bedload.

In addition to research, Yang plans to develop new curriculums and outreach activities to engage college and K12 students of diverse backgrounds in water-related research. “I am always looking for motivated students and postdocs to join my team and work together to increase the sustainability of our environment,” Yang added.