This investigation is part of GLOBEC - Global Ocean Ecosystems Dynamics - of the U.S. Global Chenage Research Program. It is aimed at quantification of the interrelation between plankton trophodynamics and turbulence. This project stems from the fact that the literature assumes that trophodynamics and consequent population dynamics depend only on the relative density of predator and prey organisms, yet growing theoretical and empirical evidence indicates that turbulence can alter the contact rate. Using a supercomputer, turbulence can be simulated directly from the Navier-Stokes equation (DNS) so the simulated field is a "real" flow. Flow visualization at the scale of an individual planktonic organism is the best way to educate our scientific mind. Accumulated oceanic turbulence measurements provide enough information to interpret the numerically simulated turbulence as oceanic turbulent flow. A lognormal probability density function will be used to model the statistics of turbulent flow around a planktonic organism. A computer program will be developed to reduce the amount of computation required for DNS. This program will create a kinematically correct random flow field at a high Reynolds number, which is unavailable from DNS. A data base will be established for the simulated flow field for later uses. A potential use of this data base will be to test the notion of food/ingestion signals. A stochastic model will be employed to model the behavior of a planktonic organism. Currently random walk is the only model used in Lagrangian simulations, however, the organism shows much more complex swimming behavior. A modified Auto-Regressive model will be adapted for this purpose.
