Assessment of some linear food web methods

We review some recent methods for the calculation of energy fluxes through marine ecosystems in terms of linear steady-state webs. We consider some problems in using such methods as input to non-linear dynamic simulations. The problems arise from the great range in space and time scales and from the heterogeneity in data used to determine energy fluxes. These problems compromise the apparent generality of the methods and their ability to assess uncertainties in flux estimates. We consider alternative approaches and illustrate these problems and methods with a budget for the Georges Bank (north-west Atlantic) ecosystem.