reverse eutrophication processes; and to (3) develop 

 methods for monitoring eutrophication conditions and 

 for predicting the impact of nutrient sources on the 

 eutrophication of natural waters. 



1971 1972 1973 



$0.46 $0.41 $0.44 



National Science Foundation — Current research on 

 eutrophication supported by NSF grants includes 

 competitive growth responses of various algae to 

 nutrient enrichment in both field and laboratory 

 studies, responses of lake and river ecosystems to 

 enrichment, and the relevance of these findings for the 

 management of enriched aquatic systems. 



1971 1972 1973 



$0.50 $0.35 $0.82 



2. Thermal Additions 



Department of the Interior— The ecological effects 

 of thermal additions to water are studied by the Bureau 

 of Sports Fisheries and Wildlife to provide information 

 on natural productivity of fish in freshwater systems 

 and to determine the effects of environmental variables 

 and contaminants on the fishery resource. Included are 

 studies of life histories, population dynamics, and 

 environmental requirements of principal fishes and the 

 food organisms on which they depend for each of the 

 ecosystems covered. Further studies by the Office of 

 Water Resources Branch and the Geological Survey 

 deal with the interrelationships between organisms 

 and their hydrologic environment including thermal 

 additions to this environment. 



1971 1972 1973 



$0.48 $0.81 $0.96 



Environmental Protection Agency— Ecological 

 studies are conducted on thermal additions to water to 

 determine their effects on the reproduction and life 

 cycles of aquatic organisms in fresh and marine waters. 

 The objective is to improve the basis for developing and 

 implementing thermal standards. 



1971 1972 1973 



$1.00 $1.50 $2.00 



46 



