Circles of Life

Running in circles is often a criticism – a metaphor for going nowhere fast. But spiralling or chiral movement may be an effective way of cautiously exploring an environment, especially if you’re a bacterium. Here a throng of cyanobacteria – the oldest living organism on Earth – glide in and out of a droplet of water. While appearing chaotic at first, the bacteria inside the droplet stretch out like holidaymakers in a jacuzzi (although ~3000 times smaller), while cells leaving the water begin to bend, turning in a clockwise direction until they find water again. Differences in velocity between the 'head' and 'tail' of the bacteria yield this natural curve to the right. Such studies of chirality in ancient organisms may yield insights to asymmetry in other types of bacteria, but also in understanding, and tackling cyanobacteria in harmful algal blooms.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Video from work by Andrej Vilfan and colleagues
• Laboratory for Fluid Physics, Pattern Formation and Biocomplexity (LFPB), Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
• Video originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Proceedings of the National Academy of Science (PNAS), February 2026