Bulletin of the American Physical Society
71st Annual Meeting of the APS Division of Fluid Dynamics
Volume 63, Number 13
Sunday–Tuesday, November 18–20, 2018; Atlanta, Georgia
Session E26: Focus Session: From Single Swimmers to Swarms: Active Matter in Fluids at Intermediate Reynolds Numbers
5:10 PM–6:15 PM,
Sunday, November 18, 2018
Georgia World Congress Center Room: B314
Chair: Daphne Klotsa, University of North Carolina
Abstract ID: BAPS.2018.DFD.E26.3
Abstract: E26.00003 : Directed percolation theory and experiments of ultra-fast hydrodynamic quorum sensing*
5:36 PM–5:49 PM
Arnold JTM Mathijssen
Arnold JTM Mathijssen
Responding to external stimuli promptly is key to survival, so the biophysical relationships between physiological sensors and actuators were fundamental to the development of complex life forms. We study the protist Spirostomum ambiguum, which is unicellular but can grow up to 4mm in size. As a defence against predators, this ciliate releases toxins by contracting its long body within milliseconds. These rapid contractions also generate long-ranged vortex flows that trigger neighbouring cells, in turn, which collectively leads to an ultra-fast hydrodynamic signal transduction across a colony that moves hundreds of times faster than the swimming speed. By combining high-speed PIV and rheosensing experiments we determine the critical colony density required to sustain these signal waves. Synchronised toxin discharges could facilitate the repulsion of large-scale predators cooperatively, but false triggers are costly. We investigate this decision-making process in a framework of quorum sensing and percolation theory.
*AM acknowledges funding from the Human Frontier Science Program (Fellowship LT001670/2017).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.DFD.E26.3
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