IV-496 



changes in temperatures and salinities, changes in 

 circulation patterns, and destruction of physical 

 components of the system. 



(2) Species diversity and organization is simplified. 



(3) Trends toward severely modified ecosystems are 

 established. 



A review of recent literature indicates, however, that although 

 these effects appear to be generalized, individual estuarine eco- 

 logical systems must be studied in detail to establish precisely 

 the parameters of change involved. Due to the complexity of the 

 systems themselves, and of the causal interactions attributed to 

 man's activities, no attempt can be made to establish national and 

 regional trends in estuarine ecology. At this stage of knowledge 

 such trending, based on scientifically tested information, is 

 impossible. Yet one kind of estuarine ecological system does seem 

 to be increasingly prevalent in the estuarine zone, and may become 

 the predominant type if the impact of the socioeconomic environment 

 on the biophysical environment continues unchecked. 



THE MULTIPLE-STRESSED SYSTEM: 

 ESTUARINE ECOLOGY OF THE FUTURE? 



It seems clear that most, if not all major estuarine areas in the 

 continental United States are now or soon will be affected by 

 disturbances of more than one identifiable type. These systems are 



