STRESS AND ECOSYSTEMS 



85 



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< 

 > 



a 



< 



LU 



X 



10 



(bl 



Sun 



Tide 



Waves 



Fresh 

 water 



Nitrogen 



Fossil 

 fuel 



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a 



en 

 O 



CO 

 O 



Fig. 6 Calculation of the energy signature of a marsh ecosystem 

 under the influence of thermal pollution (a) [data from H. T. Odum 

 et al. (1977)]. The symbols in (a) are described in Fig. 2. Note that, 

 when all the energies are expressed on the basis of equal quality 

 (fossil fuel equivalents), their relative importance (c) changes in 

 comparison to calculations based on heat equivalents (b). 



