onset of a bloom is logarithmic, the period of time corre- 

 sponding to this portion of the growth curve would produce 

 a preponderance of living cells with optimal motile capaci- 

 ties. As limiting environmental factors became critical, 

 the rate of cell division would decline and mortality would 

 rise. The number of dead cells would increase, and the 

 dead cells would slowly sink, at a declining rate, as the 

 water density increased. Operation II, with an even tem- 

 perature gradient, provides a theoretical situation in which 

 the distribution of phytoplankton was a function of bloom 

 decline as well as of temperature. Tables 1 and 2 sum up 

 pertinent data for each microorganism. 



MACROPLANKTON 



The distribution charts of macroplankton (refer to 

 appendix) were compared to the temperature structure and 

 turbidity. The only positive relationship demonstrated was 

 with volume displacement. Operation I (fig. 35). The cor- 

 relation was not supported by the individual counts of macro- 

 plankton and was caused by reduction of the effective mesh 

 size of the net by clogging, so that much of the finer materi- 

 al (that is, Gymnodinium flavum) was retained and dominated vol- 

 ume displacement. 



The large relative size and low concentrations of 

 macroplankton made negligible their contribution to total 

 biomass and the attenuation of light. 



In certain cases at night swarms of mysids are 

 attracted to the light beam of the hydrophotometer and can 

 greatly affect light transmission. High numbers of copepod 

 nauplii in a freshwater lake were also shown to affect trans- 

 parency. 



The distributional patterns of macroorganisms for 

 both operations were also compared. No consistent relation- 

 ships were apparent with respect to vertical distribution, 

 diurnal migration, or tidal activity. 



60 



