plankton in the Greenland Sea. As early as June, the reproduction of large Crustacea; Calanus 

 flnmarchicus, Calanus hyperboreus , Themisto libellula and Th. abyssorum took place there . On 

 the other hand, the acceleration of the intensity of the East Greenland current was the cause of a 

 considerable chilling of the waters in the area of Jan Mayen. The low temperature of the water 

 (below + 1°) delayed the reproduction of Calanus flnmarchicus in the areas to the SE from Jan Mayen. 

 This brougjit about a reduction in the plankton biomass. The biomass there at the beginning of June, 

 1954 was one -tenth that of June, 1953. 



Figure 9. Distribution of the main plankton complexes in June, 1951. 1. pre-spawning 



accumulations of Calanus ; 2 . nauplii and young of Calanus ; 3. red Calanus at 

 the surface; 4. re; Calanus descended into the deep; 5. Phaeocystls ; 6. dia- 

 toms; 7. Calanus hyperboreus ; 8. jellyfish. (See Figure 8). 



The large nimiber of dull or cloudy days and the homogeneity of hydrologlcal conditions in 

 June -July hampered the development of phyto plankton in the central and eastern regions of the Nor- 

 wegian Sea. The "spots" and "zones" of abundant or luxuriant "blooming", common to this period, 

 were not observed in 1954. Phytoplankton developed or grew everywhere; but only In small quan- 



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