Wednesday, May 29, 11:00 in Aud. 31, Building 306: Life at High Reynolds Number
Life at High Reynolds Number
David. R. Nelson (Lyman Laboratory of Physics, Harvard University, and Niels Bohr Institute )
Microorganisms living in the ocean can be subject to strong turbulence, with cell division times in the middle of a Kolmogorov-like cascade of eddy turnover times. We explore the dynamics of a Fisher equation describing cell proliferation in one and two dimensions, as well as turbulent advection and diffusion. Because of inertial effects and cell buoyancy, we argue that the effective advecting velocity field is compressible. For strong enough compres-sible turbulence, microorgnisms such as bacteria and phytoplan-kton track, in a quasilocalized fashion, sinks in the turbulent field, with important consequences for the carrying capacity and for fixation times when two genetically different species compete.
