IV-492 



MAN'S ACTIVITIES AND ESTUARINE SYSTEM STRESS 



Part IV, Chapter 4 showed the presently identifiable trends 

 associated with population and economic development and with 

 specific activities affecting the estuarine zone. At present, 

 however, the rate of change effected by these trends on estuarine 

 ecological systems is little known. The most recent work by 

 ecologists is generally concerned with identification of system 

 types, the development of general theory, and the measurement of 

 system characteristics and operating phenomena. Much is known about 

 certain elements of estuarine ecological systems, such as tem- 

 peratures, salinities, abundance of certain biotic communities, 

 but the specific processes and causal relationships of complex 

 whole systems and interacting subsystems have only recently been 

 partially understood. 



Modification of estuarine ecological systems is nevertheless a 

 trend which can be qualitatively, if not quantitatively, observed. 

 Figure IV. 6.1 indicates the general relationships between man's 

 activities and estuarine ecological system modification. 



The Nation's population and economy have expanded rapidly in the 

 recent past and will continue to grow substantially in the foresee- 

 able future. Moderate projections indicate a doubling of national 

 population by the turn of the century. Much of this growth, 



