Stability and instability of marine ecosystems, illustrated by examples from the Red Sea

Abstract

With all the limitations of novelty, ecology today is able to discern certain practices that may be destructive to the existing ecosystems, and to predict what the damages in the systems will be if preventive measures are not taken. The aim of this paper is to present some ideas about the importance of predictable evolution of all the compounds of ecosystems leading toward the development of climax communities, with high homeostatic power. Recent perturbations, caused mostly by human activity, have disturbed the predictability of events, and as a result also the stability of ecosystem development. Such disturbances produce situations de novo in ecosystems, cause reselection of the biological partners, and eliminate the more sensitive ones. These ideas are illustrated in several investigations performed in the coral reef region of the Gulf of Aqaba, Red Sea. The results of these studies showed that the perturbations caused by man's activity increase the instability of coral reef ecosystems. This is illustrated by a decrease in the affinity of samples taken at the same spot and a decrease in the evenness of distribution. These changes produce new forms of ecosystems, unpredictable as to their final stages of development.