B. Observational and Analytic Techniques 



Nansen bottles, with deep-sea reversing thermometers attached, were 

 used to observe temperatures and to collect water samples for salinity, 

 dissolved oxygen, and inorganic phosphate determinations. The bottles 

 were placed at international standard depths; additional bottles were 

 placed where supplementary information was desired. 



Paired protected reversing thermometers were used to observe in situ 

 water temperatures. When these paired protected thermometers differed 

 by 0.06°C or more, the reading from the thermometer considered most 

 reliable was used. This evaluation of reliability was based on the 

 thermometer's previous history and the credibility of the individual 

 temperature when plotted with better documented adjacent values. 



Unprotected reversing thermometers paired with protected reversing 

 thermometers were used to calculate thermometric depth values. Depth 

 of the sample then was determined using these thermometric depths in 

 conjunction with observed wire angles. 



Salinities were determined by means of an inductively-coupled sali- 

 nometer. Each sample was subjected to two determinations, and if differ- 

 ences exceeded 0.01 %o a third determination was made. Due to equipment 

 difficulties, the 1964 salinities were analyzed at the New Zealand 

 Oceanographic Institute by U.S. Naval Oceanographic Office personnel. 



Dissolved oxygen content was determined aboard ship by this Office's 

 modification of the Swinnerton-Linnenbom-Cheek gas chromatograph parti- 

 tioner method. During the 1963 survey, aerological helium was used and 

 the results were considered tobeinvalid. In 1964, however, 77 oxygen 

 samples were analyzed by the Thompson and Robinson modification of the 

 Winkler titration method and compared with values obtained with the gas 

 partitioner. Using the modified Winkler method as an oxygen standard, 

 the gas partitioner values were considered acceptable and are included 

 on the data listings in Appendix A. 



Dissolved inorganic phosphate was determined by the Strickland and 

 Parsons spectrophotometry method. Phosphate data were obtained at less 

 than half the DEEP FREEZE 63 stations, but the data were complete for 

 DEEP FREEZE 64. 



The above physical and chemical oceanographic data were evaluated, 

 coded, and forwarded to the National Oceanographic Data Center for 

 processing by electronic computer. Machine computations provided temper- 

 ature, salinity, dissolved oxygen, and phosphate interpolations at standard 

 depths, in addition to sigma-t, dynamic depth, and sound velocity calcu- 

 lations from the observed data. 



