578 



5. Determine exchanges between the bottom sediments and the 

 overlying water mass. 



6. Increase understanding of the origin, distribution and im- 

 portance of surface films. 



7. Determine exchanges between the atmosphere and the estua- 

 rine water mass. 



It is evident that a fresh new approach to ecological research is 

 necessary if we are to gain needed knowledge and understand estuarine 

 ecosystems in time for it to be of value for management decisions. If 

 the old patterns of investigations are followed, wherein detailed 

 studies by many investigators are made on individual species, it is 

 quite probable that answers will be unavailable in time to be of any 

 real value in shaping decisions for the management of estuarine zones. 

 A highly coordinated approach to this problem is needed. One ap- 

 proach would be to concentrate research in a number of centers where 

 a high degree of proficiency exists, developing a system of coastal 

 laboratories to satisfy both national and regional needs. Extramural 

 reaserch for the most part would probably be done under contract to 

 assure appropriate direction in terms of national goals, bearing in 

 mind, however, that this direction should take full advantage of con- 

 sultation and advice from knowledgeable scientists and engineers from 

 all segments of the industrial, academic, and government communities. 



Section 5. Toxicity 



All too often data required to interpret toxic conditions are ob- 

 tained solely through field observations after the environment has been 

 irreversibly changed and an ecological catastrophe has occurred. Pre- 

 dictions and management decisions based on this kind of information 

 are poor at best. The only way that the knowledge needed by man- 

 agers to cope with potentially toxic situations can be available in time 

 to be useful is by having previously established tolerable levels of 

 pollutants, developed through bioassay techniques, and appropriately 

 extrapolated to natural conditions. Toxicity studies would be con- 

 cerned not simply with levels at which a species could survive, but 

 also at what levels it will reproduce to complete its life cycle without 

 significant change. From such studies, criteria could be established 

 much as they are for public health measures, but relevant to the 

 organisms as well as to man. Only through such long-range programs 

 can the desirable biologically productive aspects of estuaries be pre- 

 served and the other beneficial uses augmented. 



SUBLETHAL EFFECTS 



There is a growing awareness that, in the long term, the major con- 

 cern should be for an understanding of sublethal chronic effects in 

 order that realistic water quality criteria may be developed based 

 upon the interrelationships within ecological systems. Much of the 

 presently available data have been derived from acute toxicity tests 

 on adults without adequate consideration of the chronic effects upon 

 the development of organisms and communities. There is an urgent 

 need, therefore, ior diversified programs to develop new indexes of 



