MARINE ORGANISMS AND EXVIROXMEXTAL INFLUEXXES 281 



10° 20° 30°C 0° 10° 20° 30°C 



Fig. 7. Dinoflagellates: growth at different temperatures as percentage of 

 maximal growth rate (Baklcen, unpublished; Xordli, 1957). 



relatively high growth rate of Ceratium tripos at low temperatures, 

 as compared with the other ceratia studied by Nordli, gives a 

 reasonable explanation of the predominance of this species in the 

 cold season in the Oslofjord area, as compared with other species 

 of the genus such as Ceratium f urea and fusus. 



In recent experiments on a strain of Peridinium troehoideum 

 from Golfo di Napoli, the temperature optimum was found to be 

 as high as 25-30°C (Fig. 8), while the Oslofjord strain showed an 

 optimum at 20°C as did the other dinoflagellates from the Oslofjord 

 area (Fig. 7). 



