No abstract

No abstract

In conclusion, the resource (food)-feedback model of bioturbation, Eq. 3, not only predicts the existence of a finitedepth bioturbated zone in sediments, but substitution of currently available parameter values into this model indicates that the mean mixing depth should be a worldwide constant of 9.7 cm, independent of water depth or sedimentation rate. This result agrees with the data compilations in Fig. 1 and in Boudreau (1994). If this paper had dealt with a problem of physics or chemistry where predictive theories are the norm, then the model and calculations presented here would be valuable, but not overly remarkable; however, the natural sciences, and particularly geochemistry and ecology, are singularly lacking in successful quantitative theories. The complexities of the phenomena studied in these fields is thought to preclude simple and predictive explanations. This paper also illustrates the fallacy of such a belief.