544 CYCLES OF ORGANIC AND INORGANIC SUBSTANCES 



and even classes of phytoplankton organisms. Here we urgently 

 need an exact analysis of the biochemical and physiological 

 processes which are taking place. It would be interesting to learn 

 whether the total quantity of organic matter, especially of pro- 

 teins, oscillates even when the total number of cells remains 

 constant. 



Dotterweich (1940) concluded that even an indi\idual organism 

 cannot attain a balance that is really stable because of the different 

 processes of metabolism. In a biocoenosis, each individual is only 

 one component, but the total stock may become more stable with 

 an increase in the number of different components. According to 

 Friederichs (1930), a balanced biocoenosis is merely theoretical. 

 The more one tries to balance it, the more the equilibrium is 

 disturbed. It should also be pointed out that every balance must 

 be exactly defined. In our case, this means that the total quantity 

 of living matter must be constant when environmental factors 

 remain unchanged. 



Let us continue with the discussion of the model. Normally, a 

 population of phytoplankton is dependent on the dynamic water 

 movements in the oceans, especially in the surface layers. Owing 

 to turbulence the phytoplankton is transported into various layers 

 with different light intensities for varying periods of time. Thus, 

 the oscillating balance of a single cell may be disturbed and 

 depressed when the cells are carried away from the zone of optimum 

 assimilation. Then decomposition, which torms a part of the total 

 respiration, becomes larger and more phosphorus becomes a\ail- 

 able. Because of very different activities, the oscillations increase 

 in period. Steele (1959) has demonstrated four different stages in 

 the interaction between the standing stock of phytoplankton and 

 the upper turbulent layer. The extent of this layer becomes 

 critical when the uptake of physiological energy does counter- 

 balance the cell requirements. Then light becomes the limiting 

 factor, because the ordinary nutrient constituents which may at 

 times be limiting are available in sufficient quantity. The oscillating 

 balance is actually an open unbalanced system. Here it may be 

 said that a relationship exists between two entirely different forms 

 of energy. 



