2i6 DISCOVERY REPORTS 



The hydrological work of Braarud and Klem (i 931) in the area investigated by Gran, 

 has shown that the apparent correlation of the spring thaw with the main spring diatom 

 increase is probably incidental {ibid., p. 77), and that in any case the former does not 

 add to the nutrient salt content of the surface layers appreciably. It is therefore easily 

 understandable that at South Georgia, where the land is much more barren and the 

 initial phosphate content of the surface water higher, the thaw water appears to lead to 

 an actual decrease in the amount of phosphate available. 



Conditions in East Cumberland Bay do not permit of any comparison with those ob- 

 taining far offshore. However, the reasons to which the poverty of the inshore phyto- 

 plankton is attributed probably hold good all round the island. It is thus highly probable 

 that the falling off in quantity of the phytoplankton often observed at the innermost 

 stations of the lines worked on numerous surveys round the island by the research ships 

 is to be explained by the prevalence of the same adverse factors, namely, rapid move- 

 ments of the surface layers caused by wind, and the large amount of fine inorganic 

 material in suspension brought down by land drainage. This last factor greatly hinders 

 the penetration of light, and may also interfere directly with the gaseous interchanges 

 upon which the vital processes of the organisms depend. 



REFERENCES 



Atkins, W. R. G., 1930. Seasonal Variations in the Phosphate and Silicate Content of Sea Water in Relation 



to the Phytoplankton Crop. Part V. Journ. Mar. Biol. Assoc, n.s., xvi, pp. 821-52. 

 Braarud, Trygve, and Klem, Alf., 193 i. Hydrographical and Chemical Investigations in the Coastal Waters 



off More and in the Romsdalsfjord. Hvalradets Skrifter (Norske Vid.-Akad. Oslo), No. i, pp. 5-88. 

 Gran, H. H., 1929. Investigations of the Production of Plankton outside the Romsdalsfjord, 1926-27. Rapports 



et p'roces-verbaux des Reunions, Conseil Internal, pour I'Explor. de la Mer, LVI, pp. 5-1 12. 

 Gran, H. H., and Gaarder, T., 1918. Ober die Einfluss des atmosphdrischen verdnderungen Nordeuropas auf 



die hydrographischen Verhaltnisse des Kristianafjord bet Drobak im Mars, 1916. Publications de 



Circonstance, No. 71. 

 Lohmann, H., 1928. Beitrdge zur Planktonbevolkerung der Weddellsee. Beitrag II, Die Appendicularien- 



Bevolkerung der Weddellsee. Internal. Rev. ges. Hydrobiol. Hydrogr., XX, p. 16. 

 Marshall, S. M., and Orr, A. P., 1927. The Relation of the Plankton to some Chemical and Physical Factors 



in the Clyde Sea area. Journ. Mar. Biol. Assoc, n.s., xiv, pp. 837-68. 

 Station List, 1929-31. Discovery Reports, iv, pp. 222-9. 



