This aim of this short chapter is to place the DEB model in the context of research in eco-energetics, and to evaluate some of its concepts. The chapter loops back to the general introduction in the first chapter, and especially to the section on modelling, cf. {7}. I first focus on the DEB theory, as presented in this book, then follows a comparison with some other approaches to the subject of energetics.

Energetics and metabolism

Metabolism can be defined as the chemical transformation of chemical compounds (in living systems), which has energetic aspects. These energetic aspects are sometimes particularly interesting themselves; for example, the thermal balance of endotherms, or the dissipation of heat in bioreactors, or particular stoichiometries in biochemical reactions. The main role of energy in the context of the DEB theory, however, is that of an abstract variable that has close links with transformations of chemical compounds. The fluxes of many compounds through organisms are frequently closely linked to each other, and rather than following one particular compound, energy is followed. This has several advantages in systems that can be understood with only one reserve component as state variable. If the fluxes of various compounds are not closely linked, such as in photoautotrophic systems, this simplification breaks down and we need to follow a set of compounds, as well as energy (in the form of light and dissipating heat). This extension can be considered as a multi-variate analogue of the mono-variate situation.