Ocean Basin Ecosystems

Abstract

Natural scientists have for 100 years wrestled with the difficulty of formalizing the concept of a functional entity of biological and physical organization. In a review of the concept, Evans (1956) discusses Möbius’s (1877) use of biocoenose, Forbes’s (1887) use of microcosm, Markus’s (1926) use of naturkomplex, Friederich’s (1927) use of holocoen, and Thienemann’s (1939) use of biosystem; but Evans prefers Tansley’s (1935) use of ecosystem to describe the basic unit of ecology. Evans’s thesis is that there is a functional entity of biological and physical organization (i.e., an ecosystem), and that level of organization should be the fundamental unit of ecology. Two particularly important discussions of the ecosystem concept are those of Odum (1969; 1977). Odum (1969) provides our current working definition of ecosystem as the unit of biological organization interacting with the physical environment such that the flow of energy and mass leads to a characteristic trophic structure and material cycles. This definition emphasizes that the existence of a characteristic trophic structure and characteristic material cycles provides the means to determine the boundary between one ecosystem and another. The 1969 article goes on to suggest that ecological succession is a central tenet of ecosystem theory. This line of reasoning causes concern for me as an ocean ecologist, or at least as a pelagic ocean ecologist.