title: A new angle on microscopic suspension feeders near boundaries.
abstract: Microscopic sessile suspension feeders are a critical component in aquatic ecosystems, acting as an intermediate trophic stage between bacteria and higher eukaryotic taxa. Because they live attached to boundaries, it has long been thought that recirculation of the feeding currents produced by sessile suspension feeders inhibits their ability to access fresh fluid. However, previous models for the feeding flows of these organisms assume that they feed by pushing fluid perpendicular to surfaces they live upon, whereas we observe that sessile suspension feeders often feed at an angle to these boundaries. Using experiments and calculations, we show that living suspension feeders (Vorticella) likely actively regulate the angle that they feed relative to a substratum. We then use theory and simulations to show that angled feeding increases nutrient and particle uptake by reducing the reprocessing of depleted water. This work resolves an open question of how a key class of suspension-feeding organisms escapes physical limitations associated with their sessile lifestyle.
authors.affiliation: Departments of Integrative Biology and Civil and Environmental Engineering, University of California at Berkeley, Berkeley, California. Electronic address: rpepper77@gmail.com.
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Pepper
authors.forename: Marcus
authors.initials: M
authors.lastname: Roper
authors.forename: Sangjin
authors.initials: S
authors.lastname: Ryu
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Moeto
authors.initials: M
authors.lastname: Nagai
authors.forename: Howard A
authors.initials: HA
authors.lastname: Stone
mesh_terms: D059001:Aquatic Organisms / Q000502:physiology*; D004058:Diffusion; D017753:Ecosystem; D005247:Feeding Behavior; D008853:Microscopy; D008954:Models, Biological; D016802:Oligohymenophorea / Q000502:physiology*; D013535:Suspensions; D013997:Time Factors; D059008:Time-Lapse Imaging; D019415:Torque
chemical_list: D013535:Suspensions