64 



Life forms. — The estuarine zone is recognized as the most produc- 

 tive part of the natural environment. The many forms of life include 

 animals and plants which live in the bottom, on the bottom, in the 

 water, on the water, and in the marshes Avhich border much of the 

 coast. The various communities in the estuarine zone are characterized 

 by measuring the identity, distribution, and abundance of the species 

 present, ranging from bacteria and the minute phytoplankton which 

 are the primary users of solar energy to the fish, shellfish, and other 

 wildlife Avhich are the final steps in the food chain concentrating 

 solar energy for man's use. 



Water' quality. — Even raw domestic sewage is over 99 percent pure 

 water, but the infinitesimal amount of dissolved and suspended ma- 

 terial has effects far out of proportion to its mag-nitude. While ocean 

 water contains dissolved solids measured in concentrations of parts 

 per thousand, water quality measurements, except for temperature, 

 are couched in terms of parts per million and parts per billion whether 

 they are measurements of dissolved oxygen, plant nutrients, organic 

 pollutants, toxic chemicals, or any of the other parameter by which 

 pollutional levels are characterized. 



Upon the very delicate tests by which such minute concentrations 

 are measured depends the quantitative knowledge of pollution and 

 how to control it. 



Nature of the bottom. — The land under the water in the estuarine 

 zone can tell much of the history of water flowing over it. Solids are 

 deposited from the water on the bottom, and creatures and plants 

 living on and in the bottom draw their nourishment from the water 

 itself. Estuarine bottoms are characterized by the kind and amomit 

 of sediments, vegetation, and animal life found there, both near the 

 surface and much deeper. 



Esthetic a'p'peal. — Not all people enjoy the same things; the bustle 

 of the Port of Baltimore might not be appreciated by a salmon fisher- 

 man from Alaska, for example, nor might a shrimp fisherman from the 

 marshes of Louisiana appreciate the bluffs along the California coast. 

 Yet an estuary w^hich has no debris along its edge or floating in it, 

 no smell of oil, or chemicals, or sewage, no dead fish, no floating mats 

 of algae, and no peculiar color is pleasing to all. These things are gen- 

 erally subjective, and since they do not lend themselves to quantitative 

 measurement, are sometimes overlooked in evaluating the quality of the 

 estuarine environment. 



Through measurement of these six kinds of characteristics, the domi- 

 nating environmental factor in the estuarine zone can be understood 

 and made to work for the ultimate benefit of mankind. 



Section 2. The Dominating Environmental Factors 



The diversity of the estuaries, bays, inlets, lagoons, marshes, and 

 other features which make up the estuarine zone presents a discon- 

 certing picture of apparent individual uniqueness and complexity 

 without evident unifying principles for technical and political man- 

 agement. Such unifying principles do exist, however, and the estuarine 

 zone as an environment is governed by a small number of often com- 

 peting dominating factors, having interrelationships which determine 

 the nature of each individual estuarine system. Similarities and con- 

 trasts among estuarine areas in different parts of the coastline point 



