title: Dynamics of enhanced tracer diffusion in suspensions of swimming eukaryotic microorganisms.
abstract: In contexts such as suspension feeding in marine ecologies there is an interplay between brownian motion of nonmotile particles and their advection by flows from swimming microorganisms. As a laboratory realization, we study passive tracers in suspensions of eukaryotic swimmers, the alga Chlamydomonas reinhardtii. While the cells behave ballistically over short intervals, the tracers behave diffusively, with a time-dependent but self-similar probability distribution function of displacements consisting of a gaussian core and robust exponential tails. We emphasize the role of flagellar beating in creating oscillatory flows that exceed brownian motion far from each swimmer.
authors.affiliation: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom.
authors.forename: Kyriacos C
authors.initials: KC
authors.lastname: Leptos
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Guasto
authors.forename: J P
authors.initials: JP
authors.lastname: Gollub
authors.forename: Adriana I
authors.initials: AI
authors.lastname: Pesci
authors.forename: Raymond E
authors.initials: RE
authors.lastname: Goldstein
mesh_terms: D016825:Chlamydomonas reinhardtii / Q000166:cytology / Q000502:physiology*; D004058:Diffusion; D009068:Movement / Q000502:physiology*; D011336:Probability; D013535:Suspensions; D013550:Swimming
chemical_list: D013535:Suspensions