STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 7 



by sea-birds as a resting-platform ; but on the whole this stagnating 

 area is as devoid of animal life as it is of movement. 



There is a corresponding and not dissimilar area in the South 

 Atlantic, which also has calms. It has never been named, though 

 it could well be called the Southern Sargasso. These Sargasso areas 

 contain fewer plants and animals than any other part of the ocean. 

 In both there is a rather fluctuating and not very well marked line or 

 lines of convergence between the warm equatorial waters and the 

 comparatively cool temperate waters. 



We must now return to the temperate waters, which, as we have 

 seen, form a drift right across the Atlantic and into the Polar Basin. 

 starting on the west below latitude 30 °N. and reaching latitude 70 °N, 

 or more on the east side. The counter-movements and mills consequent 

 on this great temperate drift are mostly in an anti-clockwise direction. 

 Thus the waters of the North Sea tend to rotate anti-clockwise, running 

 south down the British coast, east and north round the Heligoland 

 Bight, and north-west from southern Norway. In the Norwegian 

 Sea two major and several minor anti-clockwise mills can be detected, 

 and the waters of the Barents Sea also tend to revolve anti-clockwise. 



But the greatest counter-movement in the North Atlantic is com- 

 posed of the Greenland and Labrador currents, carr)dng cold, heavy 

 water south past Labrador, past Newfoundland and far down the 

 United States' eastern seaboard. This great counter current sets 

 south along the east coast of Greenland down the Denmark Strait 

 between Greenland and Iceland, round Cape Farewell, the southern 

 tip of Greenland carrying with it many bergs tumbled from the sliding 

 glaciers of the inhospitable east Greenland coast, runs north some 

 hundreds of miles up the west coast of Greenland, then west and once 

 more south, collecting the ice of Davis Strait and Baffin Island, and 

 pursues its final course down the Labrador shore. As it turns the 

 corner of Newfoundland and passes over the great shallow Banks, 

 it deposits its last icebergs and suddenly impinges on the northern 

 boundary of the Gulf Stream or W^est Wind Drift. Here a long, 

 well-marked line of convergence extends for many hundreds of miles. 

 The cold water sinks rapidly under the warm, and much turbulence is 

 the result. Many organisms are brought to the surface. There is a 

 steep temperature-gradient and frequent climatic upheavals, including 

 fogs. It is largely because of the cold Labrador current that New 

 York, though a full ten degrees farther south, enjoys a climate similar 

 to that of London though with greater extremes of temperature. 



