274 POLAR PROBLEMS 



Sten Vallin on the whaling cruise of Captain C. A. Larsen in Ross 

 Sea in 1 923-1 924 shows that conditions are the same there. The 

 condition of mesothermy may therefore be assumed to exist in the 

 sub-Antarctic and Antarctic seas throughout the whole circuit of 

 the South Polar regions. The cooling influence of the inland ice is 

 thus resisted from the far tropics and to a certain extent overcome. 



Position and Origin of the Intermediate, 

 OR Tropical, Water 



The southern end of this warmer intermediate water lies at the 

 edge of the Antarctic continental shelf or on its outer parts. It does 

 not reach to the outer wall of the inland ice, as the above figures 

 unanimously show. From observations in the region of the Gauss- 

 berg of an extraordinary development of plankton in February it 

 was evident that this warm intermediate water increases in thickness 

 during the southern summer and then sends forth weak thrusts of 

 warm water farther into the shelf sea. On such occasions the shelf-ice 

 masses in front of the inland-ice walls, such as the Ross Barrier and 

 the "West Ice" of the Gauss expedition, are reached in places by its 

 southernmost projections. 



That this intermediate water originates in lower latitudes may 

 be assumed, on the one hand, because of its warmer temperature; 

 on the edge of the continental shelf it dififers by 2° to 3° C. from the 

 water lying above and below it. Its higher salinity also points to the 

 fact that it comes from warmer seas in the north. For this reason it 

 may also be observed that on the southern side of islands, i. e. on the 

 lee side of its movement, it is separated. For example, considerable 

 differences in the temperature of the deep water occur on both sides 

 of the Kerguelen-Gaussberg ridge (Fig. 4), and from this the con- 

 clusion may be drawn that this intermediate warmer water flows 

 southward in greater volume on its western side than on its eastern 

 side.^° Similar conditions were found by Arctowski in the extreme 

 southeastern Pacific region on both sides of Peter I Island. ^^ In 

 addition W. Brennecke,'^^ from his observations during the Deutsch- 

 land expedition, and A. Merz and G. Wiist^^ from the older material 



10 Drygalski, Ozean und Antarktis, pp. 406, 499 ff- 



idem: Der Kerguelen-Gaussberg-Rucken, eine submarine, vulkanische Hohenzone im Indisch- 

 Antarktischen Gebiet, Sitzungsber. Bayer. Akad. der Wiss., Math.-naturw. Abteil., Munich, 1924, 

 pp. 157-164. 



11 Expedition Antarctique Beige: Rapports Scientifiques, Vol. S, Part II, pp. 23 ff.; also J. Rouch: 

 Oceanographie physique (Deuxieme Expedition Antarctique Frangaise 1908-1910, commandee par 

 le Dr. Jean Charcot: Sciences physiques, Documents scientifiques), Paris, 1913. P. 3i- Cf. also 

 Nordenskjold, op. cit.. Vol. i, No. 2, p. 18 and Pis. 3 and 4. 



1- Brennecke, op. cii., pp. 137 ff. 



" A. Merz and G. Wust: Die atlantische Vertikalzirkulation, Zeitschr. Gesell. jiir Erdkunde zu 

 Berlin, 1922, pp. 1-35; 1923. PP- 132-144- 



W. Brennecke and G. Schott: "Die atlantische Vertikalzirkulation": Eine Entgegnung auf 

 die Abhandlungen von A. Merz und G. Wiist, ibid., 1922, pp. 277-288. 



A. Merz: Temperaturschichtung und Vertikalzirkulation im Siidatlantischen Ozean nach den 

 "Challenger"- und " Gazelle "-Beobachtungen, ibid., 1922, pp. 288-300. 



