Microbes living in a confined space can push up against each other with enough force to physically damage their environment.
A team led by Oskar Hallatschek of the University of California, Berkeley, created a microscopic chamber that would hold roughly 100 cells of budding yeast (Saccharomyces cerevisiae). As the cells proliferated, they did not leave the chamber in a steady stream through a narrow exit channel but instead jammed together, building up contact pressures of almost 1 megapascal. This force was enough to cause cracks in agar gels containing growing yeast cells, and to slow down the organism's growth.
Self-driven jamming may help microbes to invade soft materials, which could contribute to biofouling — the accumulation of unwanted microbial material on surfaces, the authors say.
Nature Phys. http://dx.doi.org/10.1038/nphys3741 (2016)