MARINE ALGAL VEGETATION 



31 



Iceland a physiognomy different from that of the surrounding sea, 

 the distribution of temperature being different even if the tempera- 

 ture is not in any important degree higher than in the East Ice- 

 landic polar current itself." 



The conditions of the currents in N. and E. Iceland are evidently 

 very complicated, and only the direction of the current of the 

 warm water has been given above in outline, but as the observations 

 are so few it is difficult to form an opinion as to how the condi- 







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Fig. 2. Map of Currents. 

 (Helland-Hansen and Nansen.) 



tions of the currents along these coasts vary in other respects from 

 year to year or according to the seasons. 



Further, other current -movements occur in the coast-water 

 which may be deemed to be of importance to the vegetation, 

 that is, such movements as are due to varying specific gravity. In 

 the summer (Nielsen, 52, p. 8) the surface-water along the coast 

 is lighter on account of its mixing with fresh water. A surface- 

 current from the coast outwards then arises, and an under-current 

 from the depth towards the coast. In the winter the surface-water 

 along the coast becomes heavier owing to cooling, and sinks. Then 

 a surface-current from the ocean towards the coast arises, and an 

 under-current from the coast towards the depth. 



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