Natural control mechanisms in models of aquatic ecosystems

Based on cybernetic categories of natural control mechanisms, four generati ons of ecosystem models are distinguished: feed-forward, feedback, self-ada ptation and self-organization models. The analysis of the natural control m echanisms in aquatic ecosystems suggests that different processes are contr olled in different ways, and, although the four mechanisms were identified in historical sequence, they all operate simultaneously. The concept of sel f-organization of an ecosystem is introduced and specified for a model of a n aquatic pelagic ecosystem. The concept of the ecosystem as a multilayer, multigoal and multiechelon hierarchical system with hierarchy of the levels of biological organization is also introduced. (C) 2001 Elsevier Science B .V. All rights reserved.