title: Oscillatory flows induced by microorganisms swimming in two dimensions.
abstract: We present the first time-resolved measurements of the oscillatory velocity field induced by swimming unicellular microorganisms. Confinement of the green alga C. reinhardtii in stabilized thin liquid films allows simultaneous tracking of cells and tracer particles. The measured velocity field reveals complex time-dependent flow structures, and scales inversely with distance. The instantaneous mechanical power generated by the cells is measured from the velocity fields and peaks at 15 fW. The dissipation per cycle is more than 4 times what steady swimming would require.
authors.affiliation: Department of Physics, Haverford College, Haverford, Pennsylvania 19041, USA.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Guasto
authors.forename: Karl A
authors.initials: KA
authors.lastname: Johnson
authors.forename: J P
authors.initials: JP
authors.lastname: Gollub
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D016825:Chlamydomonas reinhardtii / Q000502:physiology*; D009068:Movement / Q000502:physiology; D011336:Probability; D012212:Rheology; D013997:Time Factors