Table 2.1 represents the context within which the vision of the ocean ecosystem may be framed. According to the Convention on Biological Diversity (1992) the ecosystem is ‘a dynamic complex of plant, animal and micro-organism communities and their non-living environment interacting as a functional unit’ (Article 2). As a result, it is thought of as a system including two components; the abiotic component, comprising the nonorganic elements of the environment and subject to physical and chemical processes, and the biotic component, which is subject to biological processes and interacts with the abiotic component. In this chapter attention will be concentrated on the abiotic component, while the biotic component will be presented and discussed in the next chapter. The abiotic component of the ocean ecosystem includes (a) the composition and processes of the lower atmosphere of which climate is the key manifestation, (b) fresh, brackish and saltwater (the hydrosphere’s elements and processes), and (c) soil features

consisting of geology and geomorphology (the lithosphere’s elements and processes).