VI-122 



waters, precipitated, and adsorbed to bottom sediments. The 

 presence of high concentrations of copper varying from 209 

 to 600 parts per million on a dry mud basis are also found. 

 These are due to sewage effluents containing human excreta. 

 Nickel is present in amounts ranging from 290 to 1,300 parts 

 per million in muds which are polluted with industrial waste. 

 Investigations of conditions effecting the biological 

 and chemical release of adsorbed or precipitated nutrients 

 and toxicants from marine benthic environments are essential. 

 The bottom sediments also serve as a reservoir into which these 

 materials may be extracted from the water mass. They can also 

 serve as the reservoir of carbonate materials which help to 

 maintain the innate buffering system of marine waters. Thus, 

 any consideration of the estuarine ecosystem must include full 

 understanding of the relationship between the bottom sediments 

 and the overlying water mass. 



Air-Water Interface 



The fourth major interface, that of the water and the atmosphere, 

 frequently is ignored in investigations. These interfaces are 

 characterized by surface films which are areas of concentration 

 not only of surface active materials, but of bacteria and other 

 microorganisms as well as inorganic particles of various kinds. 

 These natural films should be distinguished from layers of oil 



