131 



PROFILE NO. 12— STATIONS 315-319. 



The section runs from station 319, in on the Bank, 100 miles off- 

 shore to the westward. It was taken June 3-4. 



Salinity. — The water inshore on the Bank was fresher than 33.0Voo- 

 Proceeding offshore increasingly Salter water was passed through out 

 to station 317, 30 miles off the slope, where the salinity was at a 

 maximmn for the entire section. But this saltest water was in the 

 form of a wall, only some 15 miles wide at the surface with decidedly 

 lower salinities offshore, in a sm-face pool 75 to 100 meters (41-55 

 fathoms) deep at the outer stations, 315 and 316. Below 250 meters 

 (137 fathoms) the whole breadth of the section cut water of a com- 

 paratively uniform salinity, 34.5 "/oo-35 "/oo- 



Temperature. — The coldest water in the section was on the bottom 

 of the Bank at the inner station, 319, but even this minimum, being 

 above 0°, was not so low as the bottom temperature on the Bank a 

 month previously. (See profile No. 8.) The striking feature of the 

 profile, however, is the trough of warm water, >10°, 150 meters (82 

 fathoms) deep and 11 miles wide, lying 30 miles off the slope at sta- 

 tion 317 and occupying the same general position as the wall of 

 saline water shown in the salinity profile. At the outer station, 315, 

 warm water > 10° was again found, but restricted to the upper 200 me- 

 ters (109 fathoms), and separated from the trough of still higher temp- 

 erature just mentioned by a cooler band. The presence of warm saline 

 water, in trough form at station 317 and in roimded form offshore, 

 has been observed before in this locaUty and, as now, was held to be 

 attributable to the northern edge of the Gulf Stream, which tends to 

 work northward in the surface layers of the oceanic triangle west of 

 the Tail. (See Treasury Bull. No" 10, profile No. 1.) 



Comparing his section with those taken at the same place, 90 miles 

 from the Tail, at three different times during the ice season, brings 

 out the following facts : 



April 17: An unusual amount of Arctic water was spread out in 

 the upper 260 meters (142 fathoms) and to a distance of 120 miles 

 from the slope. 



May 4 : A great shrinkage had occurred in the polar water, which 

 now extended only 42 miles seaward from the slope and to a depth of 

 350 meters (191 fathoms) on the continental edge. 



June 4: Continued shrinkage in the Arctic water had taken place, 

 resulting in its complete disappearance during the brief period of one 

 month. Evidence of the arrival of Gulf Stream water is found in the 

 profile. 





