lation designed to protect rivers and streams. A basic property of all 

 natural ecosystems is that they are open-ended; that is, there is a contin- 

 uous flow of energy, nutrients, and pollutants across ecosystem boundaries. 

 To be effective, any form of environmental management must recognize this 

 fundamental principle. 



LITERATURE CITED 



Boysen- Jensen, P. 1914. Studies concerning the organic matter of the 

 sea-bottom. Rep. Danish Biol. Sta. 22:1-39. 



de la Cruz, A. A. 1973. The role of tidal marshes in the productivity 

 of coastal waters. Assoc. Southeast. Biol. Bull., 20(4) :153. 



de la Cruz. A. A. 1977. Present status and future needs of primary 

 study in freshwater wetlands. Proc. Symp. Freshwater Marshes: present 

 status and future needs. Rutgers Univ. 



Hackney, C. T., and A. A. de la Cruz. 1977. Transport of suspended 

 particulate materials and factors affecting their concentration in 

 a Mississippi Tidal Marsh System (unpublished). 



Keefe, C. W. 1972. Marsh production: a summary of the literature. 

 Univ. Texas, Contributions to Marine Science, 16:163-181. 



Matthiessen, G. C. 1962. Tidemarshes: a vanishing resource. 

 Massachusetts Audubon Society. 



Odum, E. P. 1961. The role of tidal marshes in estuarine production. 

 The Conservationist, June-July. 



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