Many naturally occurring microorganisms can produce soap-like substances, called biosurfactants, that alter how fluids and other substances in the liquids move through porous spaces such as soils and biological tissues. However, scientists still do not know how far and how fast these biosurfactants spread or how they redirect substances ranging from nutrients and pollutants to disease-causing bacteria. Yet, these microbial agents play important roles in the health of soils, plant roots, and even human lungs. This project tackles this knowledge gap by using laboratory models that mimic real soils to observe the microbes and biosurfactants in action and quantify their influence on the transport of fluids and dissolved chemicals. Outcomes from the project could support improved soil remediation strategies, more sustainable agricultural practices, and new methods to manage the spread of harmful bacteria. The project also promotes national goals in science and education by training undergraduate and graduate students, supporting interdisciplinary collaboration, and conducting outreach activities to help K-12 students appreciate fluid mechanics and microbiology and their relevance to daily life. This project integrates multiscale experiments and physics-based modeling to investigate how biosurfactants and the microbes that secrete them alter mass transport in unsaturated porous media. The goals are to: (1) quantify how time-dependent biosurfactant production alters transport beh