OCEAN PLANKTON POPULATIONS AS EXCITABLE MEDIA

Plankton populations undergo dramatic surges. Rapid increases and decr eases by a factor of 10 or more are observed, often separated by relat ively stable interludes. We propose a description of plankton communit ies as excitable systems. In particular, we present a model for the ev olution of phytoplankton and zooplankton populations which resembles m odels for the behaviour of excitable media. The parameter dependency o f the various ''excitable'' phenomena, trigger mechanism, threshold, a nd slow recovery, is dear, and permits ready investigation of the infl uence of properties of the physical environment, including variations in nutrient fluxes, temperature or pollution levels.