in the Amundsen Sea in 1,600 fathoms. From Cape Colbeck to the Amundsen 

 Sea, colder water overlays somewhat warmer water j from there eastward 

 through the Bellingshausen Sea the coldest water lies at a depth of 

 about UOO feet. 



h, Bransf ield Strait 



Figure 1? shows five BT traces for the Bransfield Strait area during 

 early February 1955. The most westerly cast shows a thermal structure 

 similar to that obseived in the Bellingshausen Sea, the coldest water 

 occurring between 200 and UOO feet depth. At the Deception Island 

 station (BT slide 229) the influence of wanner water flowing south from 

 Drake Passage is evident in the upper layers. This warm surface water 

 is still in evidence at the mid-strait station (BT slide 230), but is 

 no longer evident at the D'Urville Island station (BT slide 231). 



5. Weddell Sea Area 



Bathythermograph traces from casts taken in the Weddell Sea area 

 during February 1955 are shown in figure 18# Since the ATKA's track 

 followed along the edge of the pack ice, cooling of the surface layers 

 (which is evident in slides numbered 2lili, 252, and 260) is probably- 

 caused by melting ice. Slide number 271 was taken in Penguin Bay at 

 the edge of the fast bay ice. Upon leaving the Weddell Sea along a 

 more easterly course, the traces become sijnilar to those of the 

 Bellingshausen Sea where the coldest water was fotind about UOO feet 

 below the surface (traces 11, 20, U7, U8, 61 and 77). 



6, Conclusions and Recommendations 



Bathythermograph casts were made hourly throughout the cruise 

 exc.ept when the ship was in ice where BT casts were made every k houi^. 

 The slides from these casts are on file at the I^drographic Office and 

 the data are available upon request. Routes followed enroute to and 

 on the return voyage from the area of operations were selected to cover 

 areas not hitherto travelled by ships equipped with BT's, so that a 

 considerable amount of new data was acctuaulated, particvilarly off the 

 eastern coast of South America, 



Further e^qjeditions would do well to repeat the observations across 

 the Antarctic Convergence, particularly between longitudes 80° and 160° W. 

 where no information exists. It would also be of considerable interest 

 to run a line of closely spaced bathythermograph casts through Bransfield 

 Strait in order to portray the corplex thermal structure caused by inflow 

 of warmer Drake Passage water and cold water from the Weddell Sea, 



U3 



