128 Marine Microbiology 



The experimental investigations were accompanied by con- 

 tinuous obsenations on the quantitative changes of plankton 

 algae in the sea by direct count of cells. 



The two main groups of plantonic algae of the Black Sea, 

 the diatoms and the dinoflagellates (in general more than 50 

 species) were studied from 1952 to 1960, with special attention 

 to the species: Chaetoceros socials, Chaetoceros curvisetus, 



TABLE 1 



Maximum Division Rate of Plankton Algae 

 OF THE Black Sea in cultures 



Species 



Time Between 



Month of Division of Mean Monthly 



Maximum Cells Temperature 



Development (in Hours) (C°) 



Diatomeae 



Skeletonema costatum (Grev) CI. IV 

 Chaetoceros socialis f. 



vernalis Pr.-Lavr. V 

 Chaetoceros socialis f. 



autumnalis Pr.-Lavr. IX 



Chaetoceros curvisetus CI. IV, V 



Leptocylindrus danicus CI. VIII 



Cerataulina hergonii Perag. IX 



Thalassionema nitzschioides Grun. V, IX 



Coscinodiscus granii Gough VI 



Coscinodiscus janischii A.S. X 



Rhizosolenia alata Bright V 



Rhizosolenia calcar avis Schultze VIII, IX 



Ditylum brightwellii (West) Grun III 



Dinoflagellatae 



Exuviaella cordata Ostenf VIII 



Prorocentrum micans Ehr. VII, VIII 



Peridinium steinii Jorg. VII 

 Peridinium triquetrum (Ehr.) Lebour IX 

 Peridinium trochoideum (Stein) Lcmn. XI 



Gymnodinium wulfii Schiller VI, VII 

 Glenodinium lentictila 



(Bergh) Schiller VII 



Ceratium furcn (Ehr.) Dujardin VII 



Volvocineae 



Chlamdyomonas minima Schiller VII 



Carteria willei Schiller VI 



10 

 14 

 11 

 12 

 19 

 18 

 30 

 20 

 28 

 24 



15 

 12 

 19 

 10 

 16 

 14 



24 

 48 



12 

 6 



17 

 19 



21 

 17-19 



25 



21 

 19-21 



24 



18 



19 

 21-26 



13 



26 

 26 

 26 



17 



24 



23-26 



26 

 26 



26 



24 



