How fluid, sediment, and biota interactions regulate aquatic ecosystems by Dr. Yang

• Dr. Judy Yang, currently a McKnight Land-Grant Assistant Professor in the Department of Civil, Environmental, and Geo-Engineering and Saint Anthony Falls Laboratory at the University of Minnesota will give a presentation on How fluid, sediment, and biota interactions regulate aquatic ecosystems.

A wide variety of global environmental issues involve physical and biological interactions among fluids, particles or surfaces, and microbes at both micro- and macro-scales. For example, macro- or channel-scale sediment transport, a key process that controls coastal erosion, can vary by several orders of magnitude due to micro-scale sediment-sediment and sediment-bacteria interactions, including aggregation and biofilm formation. Other examples include clay algae flocculation, one of the most promising methods to remove harmful algal blooms, and soil carbon storage, responsible for the uptake of about 20% of annual anthropogenic carbon emissions, both of which are strongly impacted by the physical and biogeochemical interactions between particles and microbes at the micro-scale. Experimental studies of fluid- particle/surface-bacteria interactions across both micro- and macro-scales are needed to address these issues, yet such experiments are currently lacking. In this talk, I will first discuss how my group designs microfluidic experiments to study biofilm formation on surfaces under various flow conditions and the sorption and degradation of organic matter in soil. Second, I will discuss how we design meso-scale (centimeter- to decimeter-scale) experiments to study bacterial spreading in a model soil. Third, I will discuss how we design macroscale flume experiments to study the impact of microscale aggregation and mesoscale biota on sediment transport and hyporheic exchange. Afterward, I will discuss how my group is integrating technologies at different scales to advance fundamental understanding of multiscale biota- particle-fluid interactions to address a variety of environmental issues.