3. Geographical locations having mild climates and long grow- 

 ing seasons are most favorable for enrichment because of 

 temperature and light factors, 



Uo Heat and light are essentials that may be regulated to some 

 extent by control of border and surface vegetation. 



5. Turbidity^ other than that caused by plankton^ is undesirable. 

 Plankton turbidity is a consequence of the productive metabolism 

 of water and may sometimes be of value. 



6. Rate of water exchange should be at a minimumo 



?o The nature of the bottom affects nutrient loss and productive 

 ability. 



Biological Considerations 



The organisms in an aquatic habitat, relative to fertilization and 

 productivity, were discussed in some detail by Schaeperclaus (1933) - His 

 interpretation of the biological complement, with modification, placed 

 the important flora and fauna in three groups: 1. Basic producers (bac- 

 teria, water molds, phytoplankton, soft waterflora and microfauna)j 2. 

 Intermediate consumers (zooplankton, insects, and other benthic fauna); 

 3. Ultimate consumers (fish). Wiesner (1937) referred to the binding of 

 nutrient elements by organisms as "biological absorption", while Meehean 

 (1935), Lawson (1937) j, Smith and Swingle (I9I4.O), and others indicated the 

 importance of bacteria and higher flora acting in that capacity: Plants 

 also act as a storehouse for nutrient elements (Surber, 19U7) » Inverte- 

 brate fauna links flora to fish in the simplified nutrient chain (Lawson, 

 1937 J Smith and Sxijingle,, 19iiO) , but all orgc^nisras are not beneficial to 

 the productive cj''cleo Nutrients may be lost tenporarily or permanently 

 through the action of denitrifying and sulfate- reducing bacteria (Lawson, 

 1931) Zuur, 19^2), blue-green algae (Easier and Einsele, 19^8), and 

 emergent aquatic plants (li/iesner, 1937) = Excessive growth of soft water- 

 flora may tie up nutrients, crowd the water, or cause anaerobiosis upon 

 decay (V/iebe, 193U| Meehean, 1935) • 



These organisms may be considered, to great advantage, in the pattern 

 of a food chain, or succession of biota from nutrients to removable cropo 

 Meehean (1933) proposed alternative food chains in black-bass culture, and 

 later (Meehean, 193U) outlined a more simplified chain terminating with 

 bass finger lings 



Organic Protozoa 



Fertilizer —^ Bacteria — ^ Rotlfera -^ Zooplankton -y Chironomids 



Nauplii (as Daphnia ) Ostracods 



\ / 



Bass fry ^ Bass fingerling 



