Charac,eris.,cs of ,he wa.er-masses or ,hc PK,„ppi„... K.nnadcc and U,„^ , ,.,.„„ 4,, 



thermal convection. 'settlement ol the particles, must give rise to 



THE TONGA-KERMADEC TRENCHES 



c 34.00 

 20 



I5» — 



I0« 



O* 



34.50 



8500 



35 50 X. 



T 1 1 r 



-I — I — I — r 



200 



"1 — I — I — I — [- 



,•200 



V6e45 

 3500' igooo 



1 



I 



X 



J_ J 



Fig. 4. T-S diagram of the water masses of the Philippine and Kerniadcc Trenches. I xccpt foi 

 the uppermost and lowermost observations the figures along the cur\es denote hundreds of m 



position, which is much closer to the sources of the bottom water of the Pacitic 

 This is shown by the minimum temperature, 1-07^ C, at about 5000 m (see Figs. 1 

 and 4). Here also the increase in temperature towards the bottom closely rollings 

 what would be expected from adiabatic heating. 



Galathea Station nr. 686 was taken in the Tonga Trench. 8 degrees of latitude north 

 of the full series of observations of St. 677 in the Kermadcc Trench. Lack oi time 

 prevented us from making more than three observations, but they arc sullicicnt 

 to prove that the deep water is essentially the same. This corroborates \sell the results 

 from the echo-soundings, that the connection between these trenches is below the 



