WETLAND AREA 

 MUDFLAT AREA 

 OYSTER REEF AREA 1 



TOTAL 

 INTERTIDAL 

 AREA 



Driving force or onergv source - indicates 8 lource of energy outtide the tyitem under consideration. Example: Staady 

 flowing source - rive rjvari able source - sunlight. 



^ X X^ ^ Energy or material storage tank — indicates passive storage of energy or matter within the system. Example: energy itorad 

 ^\^^ / in a water tank: water contained with an estuarine basin. 



Interaction or work gate - indicates the interaction of two or more types of energy required for a process. Example: fer- 

 tilizer requirements for plant growth. 



Production unit or green plants — indicates the processes, interactions, storage, etc., involved in producing high-quality 

 energy from dilute sources like sunlight. Example: biomass of green plants. 



^ 



>l/ HMt sink — energy lottet to heat according to the Mcond law of tharmodynamics. 



Figure 22. Regional level conceptual model and explanation of symbols, 



72 



