308 



A review of recent literature indicates, however, that although these 

 effects appear to be generalized, individual estuarine ecological 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 laiowledge 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 envi- 

 ronment on the biophysical environment continues unchecked. 



THE MULTIPI^-STEESSED SYSTEM: ESTUARINE ECOLOGY OP THE FUTURE? 



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

 tinental United States are now or soon will be affected by disturbances 

 of more than one identifiable type. These systems are characterized 

 by heterogeneous patches of chemicals, fertilized waters, waters low 

 in available oxygen, turbidities, acids and other conditions alien to 

 normal life of estuarine ecosystems. The multiple stressed situation is 

 possibly the Nation's most urgent estuarine problem because the condi- 

 tion is a mixture and the causes several. The stress of many different 

 kinds of wastes may be more difficult for an ecosystem to adapt to than 

 separate types of wastes acting alone. The continual fluctuations re- 

 quire more kinds of adaptation than there may be food energies to sup- 

 port. Some bays receiving mixed wastes which are primarily nutrient 

 of non-toxic nature may develop extremely high metabolic rates and 

 high rates of photosynthetic production. Such bays are almost micro- 

 organism cultures, but have active larger animal populations too. Po- 

 tentially such fertile waters are a food-producing resource, although we 

 know relatively little about the conditions for management of these 

 mixtures which will channel energies into products of use to man, 

 effectively mineralize the wasteSj and stabilize the ecosystem. 



Areas already noted as exhibiting these characteristics are, not sur- 

 prisingly, those systems associated with concentrations of population 

 and economic activity such as Boston Harbor, New York Harbor, 

 Raritan Bay, portions of Chesapeake Bay, Tampa Bay, Galveston Bay 

 and San Francisco Bay. 



In a typical example, which is found in Galveston Bay, one major 

 development alone, the petrochemical complex, is identified as con- 

 tributing 12 major sources of modification to this naturally rich 

 estuarine complex. At least seven identifiable stressed systems result : 

 Sewage waste, dredging impoundments, petroleum snores, pilings, 

 brine pollution, and petrochemical wastes (IV-6-8) . 



Situated at the upper end of Galveston Bay, Tex., is the Houston 

 ship channel along which are located dozens of major industries that 

 release wastes. Refineries, petrochemicals, sanitary wastes, and many 

 others go into waters that pass out into Galveston Bay. The dredged 

 channel is 40 feet deep, floored with waste sludge and generally black, 

 and sometimes stratified with more saline waters on the bottom. Condi- 

 tions are patchy, often low in oxygen, and often with high concentra- 

 tions of oxidants and reducing compounds. 



Similarly, one of the most fertile estuaries in America is Tampa 

 Bay, that receives municipal wastes, food processing wastes, the out- 

 flows from phosphate district of Florida, and many other wastes. 

 There are high concentrations of cells, nutrients, and other organisms. 



