Microbe-fluid-sediment interactions in aquatic and terrestrial ecosystems*

A wide variety of global environmental and health 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 discuss how I use flume experiments to study sediment transport, microfluidic experiments to study soil carbon dynamics, and meso-scale microbial experiments to study bacterial spreading in soil. Afterward, I will discuss how my group is integrating technologies at different scales to develop fundamental understanding of biota-particle-fluid interactions to address the above global issues.