The power and reactive continuum models as particular cases of the q-theory of organic matter dynamics

Abstract

The reactive continuum model (Boudreau and Ruddick, 1991), the power model (Janssen, 1984; Middelburg, 1989), and the q-theory (Bosatta and Ågren, 1991a) have been used to describe decomposition of organic matter; the reactive continuum model has also been used to model the kinetics of kerogen cracking, i.e., of oil and gas generation (Burnham et al., 1987). The reactive continuum model describes the organic matter as being composed of a continuous distribution of reactive types; the basic premise in the power model is that the reactivity of organic matter decreases with time. The q-theory is based on the idea that organic matter is composed of an infinite spectrum of interacting (through microbial and physicochemical processes) reactive types. We show here that the reactive continuum model and the power model can be deduced as particular cases of the q-theory. The q-theory reduces to the reactive continuum model if all interactions between the components of the spectrum are neglected, whereas the power model is obtained under specific assumptions about microbial properties. The q-theory is, therefore, not only mathematically more general but has also a larger explanatory power.