CHAPTER ONE
- INTRODUCTION
The concept “ecosystem” was originally used in a publication by Tansley (1935). He indicated that the organism should not be regarded without its ambient environment. Afterward Lindeman (1942) introduced the transfer of energy between the parts of anecosystem within this concept. Moreover, Odum (1953) argued that the most important contribution of the concept “ecosystem” toecological understanding was to incorporate causal relationships among the factors in an area. Later, Odum (1964) developed thefield of “systems ecology”, which concerned “the structure and function of levels of organization beyond that of the individual and species.” In addition, Odum (1968) further concluded that the core of ecosystem analysis is “eco-energetic.” Dynamic ecology,including the laws of thermodynamics, had been gradually viewed as fundamental to ecosystem theory, such as the definition of productivity as a flow of energy (Odum, 1968; Patten, 1966; Watt, 1968). Afterwards, with the application of computers and mathematics for modeling, the emphasis of ecosystem studies changed from description to prediction (Cherrett and Bradshaw,1989). By synthesizing previous works, Willis (1997) refined the definition of ecosystem as “a unit comprising a community (orcommunities) of organisms and their physical and chemical environment, at any scale, desirably specified, in which there are continuous fluxes of matter and energy in an interactive open system.” Ecosystem definitions include the concepts of a spatial area delimited by physical, chemical and biological energy fluxes and interactions that are stable over years (Odum, 1968; Society et al.,1989; Blew, 1996; Rowe, 1997; Willis, 1997). Here, we also define an ecosystem as an enduring, spatially bounded environment where biological and energy interactions are greater within than with other ecosystems.Environmental classifications help distinguish marine ecosystems, and environmental conditions determine the abundance and distribution of biological species, including fisheries (NRC, 1999; Watson et al., 2003). These conditions also influence variation in oxygen concentration, absorption and release of carbon dioxide, release of water vapor and aerosols (Schimel, 2013), and atmospheric concentrations of greenhouse gases (Doney and Schimel, 2007; Archer, 2010). Thus knowing how many marine ecosystems exist and their distribution could contribute to understanding biogeography, managing natural resources, and modelingsea-air interactions that influence climate.