Toward Canonical Trophic Aggregations

Abstract

Steady-state input-output analysis of energy flows in an ecosytem delineates the discrete steps of energy processing in a given ecosystem. The fraction of a specific flow between species which results from a given input via any integral number of transfers can be calculated. The portions of all flows which are the same number of steps from any external input may be aggregated. The mapping which creates these groupings preserves the 1st and 2nd laws of thermodynamics. The aggregated compartments are trophic in that they are ordered according to the number of transfers from an external input. They do not represent a sequential chain of energy flow in the strict sense. Transfers between compartments which are not nearest neighbors in the chain are still present. A secondary transformation which decouples the exchanges between non-neighboring compartments can be effected. In the resultant chain of flows more energy appears to be dissipated in the lower trophic levels. There is no a priori reason why the 2nd law of thermodyanmics should be preserved under the 2nd transformation.