610 



CYCLES OF ORGANIC AND INORGANIC SUBSTANCES 



JM'> 



JOOO - 



}fOO - 



4000 - 



4fOO - 



90 



OXYGEN Ml/L 



Fig. 6. Station Cavall below 2500 in; Change in oxygen content with tin.e 

 The crosshatched envelope includes all obser\ations from four cruises in 1958 

 with Araldite-coated water bottles. The observations in 1922 and 1930, almost 

 certainly from uncoated water bottles, may be too low. The observations from 

 R.R.S. Discovery II in 1952 and 1955 were from coated water bottles. Those from 

 R.V. Sarsia in 1956 were from uncoated water bottles and are all under suspicion. 



1952 there was a drop In oxygen content of the abyssal \vater of 

 nearly 1 ml /liter. Then in a further three years, half the lost oxy- 

 gen came back. In 1955 conditions were not \'ery different from 

 those throughout 1958. 



From the Sarsia observations In 1956 all the minima should 

 probably be rejected but the maxima may be sound. If they are, 

 there was a fall and a recovery of about 0.2 ml/liter between 1955 

 and 1958. 



We see that there are large fluctuations at a single station 

 within seven years which make it difficult to use this e\idence to 



