title: Preferential Sampling and Small-Scale Clustering of Gyrotactic Microswimmers in Turbulence.
abstract: Recent studies show that spherical motile microorganisms in turbulence subject to gravitational torques gather in down-welling regions of the turbulent flow. By analyzing a statistical model we analytically compute how shape affects the dynamics, preferential sampling, and small-scale spatial clustering. We find that oblong organisms may spend more time in up-welling regions of the flow, and that all organisms are biased to regions of positive fluid-velocity gradients in the upward direction. We analyze small-scale spatial clustering and find that oblong particles may either cluster more or less than spherical ones, depending on the strength of the gravitational torques.
authors.affiliation: Department of Physics, Gothenburg University, SE-41296 Gothenburg, Sweden.|Department of Physics and INFN, University of Rome 'Tor Vergata', 00133 Rome, Italy.
authors.forename: K
authors.initials: K
authors.lastname: Gustavsson
authors.affiliation: Department of Physics, Gothenburg University, SE-41296 Gothenburg, Sweden.
authors.forename: F
authors.initials: F
authors.lastname: Berglund
authors.affiliation: Department of Biological and Environmental Sciences-Tjärnö, SE-45296 Strömstad, Sweden.
authors.forename: P R
authors.initials: PR
authors.lastname: Jonsson
authors.affiliation: Department of Physics, Gothenburg University, SE-41296 Gothenburg, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Mehlig
mesh_terms: D016000:Cluster Analysis; D017709:Fractals; D006112:Gravitation; D018466:Gravity Sensing; D057446:Hydrodynamics; D015233:Models, Statistical; D008962:Models, Theoretical; D009068:Movement; D013550:Swimming