Eco-exergy to Emergy flow ratio

The ratio of eco-exergy to emergy flow is a conceptual tool derived from two orientors, emergy and eco-exergy. Orientors have been developed in the last years to give an holistic framework to ecological studies. The study of thermodynamics produced a number of functions that measure the distance from thermodynamic equilibrium of a system under study with respect to the outside environment. This index has been used in the field of ecology to indicate the solar (direct and indirect) flow required by the ecosystems to produce or maintain a unit of their organization or structure. On the other hand, the ratio of the variation of eco-exergy and emergy flow can be used to express, from an holistic point of view, the concept of pollution in an ecosystem. © 2008 Elsevier B.V. All rights reserved.