IV. LABORATORY METHODS 



A. Dissolved Oxygen 



Water samples and bottom samples were brought into the labora- 

 tory at the main base in the heated cab of the Polecat snow vehicle. 

 At NAF McMurdo, Stanford University had established a remarkably 

 well equipped biological laboratory. Erected in 1959, the size of 

 the building was more than doubled during the following year. It 

 is now a structure 20 feet wide and some 120 feet in length and is 

 equipped with refrigerators, freezers, an autoclave, a microfilm- 

 ing and viewing apparatus, constant temperature cold water aquaria, 

 and in fact everything required for advanced biological work. 

 Oxygen samples were titrated in the biological laboratory (Plate 

 XXIX) after being "doped" immediately after each cast at the ice- 

 hole hut. The standard Winkler method was employed, two 100-cc 

 samples being titrated. The sodium thiosulphate solution was 

 standardized, and a blank test made before each station run. 



B. Salinity 



Salinity samples were stored in tight-stoppered Citrate of 

 Magnesia bottles and were shipped to the oceanographic laboratory 

 of the U. S. Navy Hydrographic Office where salinities were run 

 on a University of Washington conductivity bridge ( salinometer). 

 Duplicate runs were made on each sample. Accuracies are considered 

 good to within 0.01 °/oo. 



C. Conductivity and pH 



On one occasion, conductivity tests were made by diluting the 

 sample of water 1 to 1,000 parts in order to bring the values down 

 to the scale of the Evershed and Vignoles field conductivity meter, 

 which was Intended for freshwater use. Values of pH also were 

 determined on one occasion using a Beckman pH meter. 



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