A MODEL OF PLANKTON DYNAMICS COUPLED WITH A LES OF THE SURFACE MIXED LAYER

摘要

The dynamics of phytoplankton populations are not only determined by biological processes such as growth/mortality rates, nutrient levels and predator-prey interactions, but by the distributions of the micro-organisms, which are governed by the physical structures and motions of the ocean (Denman & Gargett 1995). These biological-physical interactions take place over a wide range of different scales, e.g. upwelling gyres over many kilometres are often nutrient rich and associated with high phytoplankton concentrations, whilst individual predator-prey encounters are governed by turbulent motion on the scale of millimetres. In this presentation the influence of physical processes on an intermediate scale (tens of metres), namely those associated with the large-eddy structures of turbulence in the surface mixed layer, on a simple ecosystem will be examined. The objective of the work will be to see what characteristics of the water motion, e.g. horizontal and vertical mixing, vortical structures, are associated with high levels of phytoplankton activity, and how these are correlated with local nutrient and predatory zooplankton concentrations.