Regensburg 2025 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 43: Active Matter IV (joint session BP/CPP/DY)
DY 43.2: Vortrag
Freitag, 21. März 2025, 10:00–10:15, H44
Metabolic activity controls the emergence of coherent flows in microbial suspensions — •Florian Böhme1, Alexandros Fragkopoulos1,2, Nicole Drewes2, and Oliver Bäumchen1,2 — 1University of Bayreuth, Experimental Physics V, 95447 Bayreuth, Germany — 2Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany
Photosynthetic microbes have evolved and successfully adapted to the spatio-temporal variations of environmental parameters within their habitat. In the abscence of light, they can still sustain their biological functionality and metabolic activity through aerobic respiration. However, for the soil-dwelling microalga Chlamydomonas reinhardtii, their environment may be deprived of both oxygen and light, resulting in a significant reduction of their swimming velocity [1]. Here, we study the effect of motility and cell density of C. reinhardtii in a confined system, on the emergence of bioconvection [2]. This collective phenomenon can be reversibly switched by light and arises due to the natural tendency of the bottom-heavy cells to move against gravity. We show that the rate at which the system evolves, as well as the dominant wavelength of the instability can both be directly controlled by the number density of cells. Further, we provide insights on the internal flow fields and density profiles of single bioconvection plumes for different parameters.
[1] A.A. Fragkopoulos et al., J. R. Soc. Interface 18, 20210553 (2021).
[2] A.A. Fragkopoulos et al., arXiv:2407.09884 (2024)
Keywords: Microswimmers; Chlamydomonas; Bioconvection; Active suspensions; Living fluids