Nonlinear Phototaxis and Instabilities in Suspensions of Light-Seeking Algae

Synopsis

“Nonlinear Phototaxis and Instabilities in Suspensions of Light-Seeking Algae,”

by Aina Ramamonjy, Julien Dervaux , and Philippe Brunet

Phys. Rev. Lett. 128, 258101 (2022)

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.258101

See also the Physics Viewpoint “Complex Dance of Light-Seeking Algae in Light Gradients,”

by Anupam Sengupta

https://physics.aps.org/articles/v15/88

Motile microbes move in response to various external stimuli by biasing their swimming direction. At large enough concentrations of microswimmers, self-organized structures and flow patterns emerge, a phenomenon called bioconvection. In this paper, the authors investigate the phototactic response of a population of the Chlamydomonas algae which seeks optimal light conditions. They reveal that its response to light stimuli is highly nonlinear and that the cells’ self-organization can become unstable due to interactions between phototaxis and other bioconvection.

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