200 



Marine Microbiology 



IV 



Vi 



XI XII 



1960 



VII VIII IX 

 MONTHS 

 Ffg. 5. Variations of temperature at station A. 



I 

 1961 



ature. Particularly interesting is the omotermic regimen at a 

 depth of 10 m, where occurred "red water," the temperature of 

 which oscillated within rather narrow limits. 



As it was to be expected, pH showed decreasing values 

 from the surface to the bottom (Fig. 6). Notice the completely 

 irregular behaviour of the O m curve compared to the 20 m one, 

 showing limited changes, between 6.90 and 7.10. At a depth of 

 10 m pH behaviour was irregular which showed some connection 

 with changes in the temperature and in the contents of H.S 

 observed at the same depth. The pH values of the "red water" 

 are between 7.48, as seen on 4 April at 9 m at station A, and 7.00, 

 noticed on the same day at 10 m at station C, and a minimum 

 and maximum of H-S respectively. 



The preliminary results of counts of sulphate-reducing bac- 

 teria confirmed the ones previously obtained (7). In the water 



