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Equations
Biological Primitive Equations
The model used to create a virtual ecosystem comprises a set of primitive equations. They provide a secure scientific base for virtual ecology. The equations are derived from a reproducible experiment performed under controlled conditions à la Galileo. This method was pioneered by Lewis Fry Richardson (1920) for weather forecasting. It has proves spectacularly successful. Nowadays primitive equation modelling is used to simulate many complex physical systems. Here we show how it can be used to simulate the plankton ecosystem.
Biological primitive equations describe basic functions like photosynthesis, or foraging. They describe the response of a single plankter to its ambient environment. So individual-based modelling is a pre-requisite for gaining the bene. ts of primitive biological equations.
The success of virtual ecology depends on establishing primitive biological equtions for the functions of the thousands of plankton species found in the sea. We are still a long way from achieving that goal.
The necessary experiments have so far been been performed on only a few functions of some common species. For example, Richard Geider has derived primitive biological equations for photosynthesis from experiments on phytoplankton cultures.
Eventually marine biologists will produce a comprehensive portfolio of biological primitive equations for all the funcions of the thousands of species encountered in the ocean. Meanwhile, we invent plausible surrogates using available information, especially from . eld observations. For example, before Geider's equations were published we successfully used surgates based on Trevor Platt's analysis of . eld data. Veri. cation shows that virtual ecosystems based on these surrogates are quite credible. The accuracy of predictions will progressively improve as we substitute true biological primitive equations derived from controlled experiments.
Molecular biology
Performing experiments to derive biological primitive equations is a slow business. Looking to the future we hope that experimental data on a few key species can be extrapolated to many others by using molecular genetics, as indicated in the . gure. This is a grand challenge for marine biology in the 21st century.
