Aaron and Josh measured the height of the bacterial colony with a laser-scanning microscope called a profilometer, which reveals the waves very clearly.

New preprint! Do you like ocean waves? We found similar waves on bacterial colonies! We found that this collective behavior, known as rippling, is nothing but surface waves on an active nematic. @princeton.edu @mpipks.bsky.social @ub.edu @icreacommunity.bsky.social

www.biorxiv.org/content/10.1...

n these streams, bacteria are densely packed but can still freely move past one another. Capillary forces allow bacteria to pack densely without cell-cell adhesion, avoiding jamming.

Capillary forces organize gliding bacteria into different phases. In the movie, menisci are initially wide but weak, and bacteria form a gas. When water is made less available, capillary forces become strong and organize the colony into nematic streams. Watch until the end!

When their menisci touch, bacterial cells experience capillary attraction. Check out the video! This attractive interaction promotes bacterial aggregation.