in figure 41 an oxygen minimum layer corresponds in position with 

 the sahnity maximum layer derived from the warm Irminger Current 

 component of the West Greenland Current. Similarly, in figure 43 

 the correspondence between the oxygen minimum layer in the 

 Labrador Sea and the salinity maximum layer shown in figure 38 is 

 even more striking. This correspondence is no longer evident in the 

 Loks Land section (fig. 45), but reference to figure 43 indicates that 

 here the picture is complicated by some addition of low oxygen 

 water from the Baffin Land Current through Davis Strait. Figure 47 

 shows additional indication of downward mixing to about 1,200 

 meters along the Baffin Island side. 



In the summertime conditions shown in figures 41 and 43 the cold 

 bottom water, with oxygen values in excess of 7 ml/1, is separated 

 from the water of high oxygen values at the upper levels along the 

 Greenland coast by water of higher temperature and lower oxygen at 

 intermediate levels. In previous bulletins it has been proposed that 

 this bottom water was formed in the central Labrador Sea in winter- 

 time through vertical convection, probably not every winter and, in 

 winters of its formation, intermittently as to time and geographical 

 location. In the past very few wintertime observations have been 

 available from the central Labrador Sea. During the winter of 

 1961-62, however, several sections were occupied from the chartered 

 Erica Dan by Woods Hole Oceanographic Institution personnel. 

 These observations showed very nearly the same conditions as those 

 characteristically found during the summertime. While it would 

 appear that vertical convection occurs in most winters to depths of 

 about 2,000 meters in the central part of the Labrador Sea, the cold 

 high-oxygen bottom water must have some other source. 



As part of the International Geophysical Year the Anton Dohrn 

 and Gauss occupied several sections between Greenland and the 

 mid-Atlantic ridge from Denmark Strait to Cape Farewell in late 

 summer and again in late winter. These winter observations, made 

 from the Anton Dohrn in March 1958, are of particular interest in 

 the present discussion. They indicate that a possible source of the 

 bottom water of the Labrador Sea is water of the Norwegian Sea 

 crossing the Denmark Strait ridge and moving along bottom near 

 the foot of the Greenland continental slope, sinking as the depth of 

 water increases toward Cape Farewell. For consideration as a pos- 

 sibility the mechanism must stipulate that the contributions from the 

 Norwegian Sea across the Denmark Strait ridge are intermittent in 

 order to account for sections in which water of the appropriate 

 temperature, salinity and oxygen content is missing. 



Near-bottom water of potential temperatures of about 1.3 has been 

 found on the Greenland slope of the Labrador Sea at depths of about 

 3,100 meters along the South Wolf Island-Cape Farewell section, 

 and with potential temperatures of about 1.4 on the Labrador slope 



76 



