3. ECOSYSTEMS DESCRIPTIONS 



USE OF ECOSYSTEMS DIAGRAMS 



The ecosystems diagram approach is a procedure that integrates a large 

 amount of diverse information about a natural system into a graphic model. 

 This model may then be used to predict impacts resulting from changes in the 

 system. Collected information includes data about organisms, chemical and 

 physical factors, substrates, morphology, hydrology, and natural processes of 

 coastal areas. Any topic within these disciplines is complicated and it is 

 only through substantial inquiry and continued synthesis of both new and old 

 information that a better understanding of coastal environments results. 



A relatively new discipline, "system" science, has been essential to this 

 process. Individual small pieces concerning systems are fitted into a much 

 larger context. With the advent of this systems approach, scientists are able 

 to describe the operation of various complex natural systems that have been 

 recognized for a long time as distinct entities. The ecosystems diagram is 

 one application of the systems approach. 



Each ecosystem is made up of a number of components: populations of orga- 

 nisms, chemical materials, substrates, and other parts. Each system has not 

 only characteristics of its individual components but also characteristics that 

 result from combinations and interactions of the components. A key realization 

 regarding populations is that energy acquisition and use are basic to every 

 organism. Physiological and morphological adaptations, day-to-day functioning, 

 and evolutionary strategy are closely linked to the energy sources and stress 

 in the natural system. 



There is a network of connections between populations of species. The 

 connections include the food web, for example, as well as complicated and subtle 

 linkages with heat, salinity, sediment, fire, soil moisture, and other com- 

 ponents. 



In order to describe the complex network of the system, some common con- 

 necting link is needed. By using the first law of thermodynamics, we can 

 express the link between components in units of energy flow. Thus, energy can 

 serve as the required link. 



15 



