In an attempt to understand the dynamics of plankton populations in the worlds oceans and to study the effect of environmental changes on plankton ecosystems, a case tool has been developed to enable biologists to construct arbirarily complex simulations of a closed volume of sea water over an extended period. This Virtual Ecology Workbench (VEW) enables pre-coded science modules to be plugged together using a graphical user interface, the resulting software configuration being compiled automatically into a single sequential C code. Here we discuss the characteristics of the generated code and describe a number of parallelisation strategies for speeding up the dominant Lagrangian components of the simulation. The parallelisation is achiev...