RECENT HYDROBIOLOGICAL 

 INVESTIGATIONS 



THE GULF STREAM— AND CLIMATE AND CROPS 

 IN NORTHERN EUROPE 



By JAMES JOHNSTONE, B.Sc. 



Fisheries Laboratory , University of Liverpool 



The exploration of the seas of Northern Europe, which has been 

 carried on by most of the fisheries authorities of northern 

 countries for the last half-dozen years, is now affording results 

 of considerable value. There are still gaps in the area investi- 

 gated ; thus parts of the North Atlantic and Norwegian Sea, 

 and some small areas in British seas require fuller study. The 

 length of time, moreover, during which the work has been 

 in progress is not sufficient to enable us to detect the larger 

 periods in the physical changes of the sea-water. For these 

 reasons it would be premature to attempt any general summary 

 of the results of the investigations. Nevertheless, there are 

 some recent memoirs of very great general interest, in particular 

 the work of the Norwegian hydrographers. 



Introductory 



The main facts of the water-circulation of the North Atlantic 

 have long been known, in a general sort of way, but it may 

 be convenient to refer to them here in outline. Premising 

 that there is comparatively little recent work with direct 

 relation to this part of the ocean, 1 and that details still await 

 further investigation, the following account will be sufficient 

 for our present purpose. The impelling force of the water- 

 movements in the North Atlantic is that of the North and 

 South Equatorial Streams. A current produced by the junction 

 of parts of these bodies of water enters the Caribbean Sea and 



1 But see Matthews, " The Surface Waters of the North Atlantic Ocean, South 

 of 6o° N. Latitude, September, 1904, to September, 1905," Second Report (Southern 

 Area) on Fishery and Hydrographical Investigations in the North Sea and 

 Adjacent Waters, 1904-5, part i. (Cd. 3837), 1907, pp. 269-348. 



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