Meeting Abstract

2-2  Thursday, Jan. 5 08:15 – 08:30  Nature’s Peristaltic Pump: Quantification of Flow around the Undulating Tail of Appendicularians GEMMELL, BJ*; SUTHERLAND, K; CONLEY, K; BOUQUET, J-M; THOMPSON, E; University of South Florida; University of Oregon; University of Oregon; Sars International Centre for Marine Molecular Biology; Sars International Centre for Marine Molecular Biology bgemmell@usf.edu http://bradgemmell.wixsite.com/scientist-site

Appendicularians are pelagic tunicates (Phylum: Chordata, Subphylum: Tunicata) that can dominate zooplankton communities and their grazing can alter material flux in the water column. Understanding the mechanics and fluid dynamics of their feeding has important implications for predicting their impact on particle distributions in the upper ocean. We use high resolution, high speed video as well as a new method of micro-Particle Image Velocimetry (µPIV) to gain unprecedented spatial and temporal resolution of body kinematics and fluid motion during feeding. We show that Appendicularians produce a strikingly different flow pattern compared to other species that exhibit undulatory swimming. The resulting flows appear to be due to the tail acting as a peristaltic pump rather than a vortex-based pattern of fluid motion seen in other organisms. These findings provide insight into the unique feeding mechanism employed by these important grazers.