Ceratium fusus: The general distribution of C. fusus 

 (fig, 13) corresponded with the thermocline in essentially 

 the same fashion as the distribution of G. flavum. The areas 

 of highest population were either within the thermocline 

 (2100 6 July at 28 feet) or above it (09 00 7 July at 8 feet). 



Ceratium furca: Two centers of high population density 

 (2100 6 July at 28 feet and 0900 7 July at 8 feet) (fig. 14) 

 were distributed in and above the thermocline. A third 

 was present below the thermocline at 1300 7 July at 48 feet. 

 Between 1900 6 July and 0200 7 July the distribution pene- 

 trated the thermocline and extended to the bottom. These 

 deviations from the distributional patterns demonstrated 

 by Gymnodinium flavum, C. fusus, and other microorganisms may 

 be attributable to concentrations of dead cells that have 

 settled through the thermal barrier. 



OTHER DINOFLAGELLATES: The several species 

 of dinoflagellates (fig. 15) lumped here demonstrated the 

 same general distribution as the preceding organisms. The 

 bulk of the population was in or above the thermocline with 

 the exception of a bottom extension between 2100 6 July and 

 0200 7 July. 



DIATOMS: Present in low numbers (fig, 16), the 

 vast majority of diatoms were distributed below the thermo- 

 cline. This distribution is consistent with the conjecture 

 that they were dead cells that had settled through the thermal 

 barrier. 



TOTAL MICROORGANISMS: As was true with the 

 distribution of total cell counts and transparency, a positive 

 correlation existed between total cell counts (fig. 17) and 

 temperature gradients. The correlation was due to the 

 presence of a thermal barrier and to the fact that 86 percent 

 of the total microorganisms were represented by concentra- 

 tions of G. flavum, which correlated with thermal structure. In 

 addition, the cumulative contributions of Ceratium fusus, C. furca, 



38 



