3D Tracking of Diatom Motion in Turbulent Flow

Evan A Variano1, Luca Brandt2, Gaetano Sardina2, Mehdi Ardekani2, Nimish Pujara1, Stephanie Ayers3, Kevin Du Clos4, Lee Karp-Boss5 and Peter A. Jumars5, (1)University of California Berkeley, Berkeley, CA, United States, (2)KTH Royal Institute of Technology, Mechanics, Stockholm, Sweden, (3)University of Maine, Department of Marine Sciences, Orono, ME, United States, (4)University of South Florida, Integrative Biology, Tampa, FL, United States, (5)University of Maine, School of Marine Sciences, Orono, ME, United States
Abstract:
We present laboratory measurements of single-celled and chain forming diatom motion in a stirred turbulence tank. The overarching goal is to explore whether diatoms track flow with fidelity (passive tracers) or whether interactions with cell density and shape result in biased trajectories that alter settling velocities. Diatom trajectories are recorded in 3D using a stereoscopic, calibrated tracking tool. Turbulence is created in a novel stirred tank, designed to create motions that match those found in the ocean surface mixed layer at scales less than ~10 cm. The data are analyzed for evidence of enhanced particle clustering, an indicator of turbulently altered settling rates