127 



PROFILE NO. 10— STATIONS 309, 311-314, AND 325. 



The section, starting in on the Tail of the Bank, runs southward 

 well into the confines of the Gulf Stream. The stations were occupied. 

 May 19-31. 



Salinity. — Inshore on the Bank was found water fresher than 33%(j. 

 There was a sudden transition on the continental edge from 

 water of 33 "/qq to water of 34 ^/^,Q, restricting the Labrador C-urrent, if 

 present at all, to a very narrow zone. Just south of station 312, 

 only 60 miles from the Tail, we met salty Atlantic water >35 %(,, 

 the northern face of which, as outlined by the 35 ^/^o isohaline, was 

 nearly vertical in position and extended from the surface to the 

 limit of investigation, 750 meters (410 fathoms). This water mass, 

 represented by the shaded area in profile No. 10, occupying two-thirds 

 of the picture, grew Salter as we proceeded south, with the highest 

 salinit}^ 5'^et met on patrol, 36.45 %o, near the surface at the outer 

 station. This is pure tropical water, identical to that in the heart of 

 the Gulf Stream off the coast of Florida. 



Temperature. — A thin bottom layer of icy v%^ater lay on the Bank 

 and extended as a thin attentuation down the slope to a depth of 600 

 meters (328 fathoms). Station 312 and southw^ard was flooded by 

 an immense volume of warm water higher than 10° in temperature, 

 extending from the surface to the 750 meter level. A maximum 

 reading of 20° was obtained at the 250 meter (137 fathoms) level at 

 station 311. This body of extremely salt and warm, water lay only 

 60 miles south of the continental edge. Profile No. 10 shows a 

 decided encroachment of the Gulf Stream since the previous obser- 

 vations made April 30-May 4 (profile No. 6), and furthermore 

 indicates sufficient strength on the part of the Gulf Stream nearly 

 to efface the presence of the Labrador Current at the Tail. The 

 fact that a great diminution in the volume of Arctic water in this 

 vicinity occurred between May 4 and May 30 (see profiles No . 6 and 

 No. 10) may be attributable to Gulf Stream encroachment or to dwin- 

 dling Labrador Current, or to both. 



