CONTENTS 



Introduction page 3 



The phosphate and silicate cycles in the Southern Ocean 9 



Antarctic surface water 16 



Phosphate content at the surface 16 



Phosphate content of the 0-100 m. layer 23 



Silicate content at the surface 27 



Silicate content of the 0-100 m. layer 35 



Seasonal variation of phosphate at the surface 39 



Seasonal variation of silicate at the surface 40 



Seasonal variation of phosphate in the surface layer around South Georgia 44 



Seasonal variation of silicate in the surface layer around South Georgia . 47 



Seasonal variation of phosphate in the surface layer in the Scotia Sea . 48 



Seasonal variation of silicate in the surface layer in the Scotia Sea . . 51 



Seasonal variation of phosphate in the surface layer in 80° W . . . . 53 



Seasonal variation of silicate in the surface layer in 80° W 54 



Sub-Antarctic surface water zc 



Phosphate and silicate contents at the surface 55 



Subtropical surface water 60 



Phosphate and silicate contents at the surface 60 



Antarctic intermediate water 63 



Phosphate and silicate content 63 



Warm deep water 77 



Phosphate and silicate content 77 



Antarctic bottom water 96 



Phosphate and silicate content 96 



The regeneration of phosphate and silicate 105 



Phosphate and silicate concentration as possible factors limiting plankton 



production m 



Summary nr 



List of literature ny 



Note on the plates 119 



Plates I-XXV following page 120 



