680 EIGHTH PACIFIC SCIENCE CONGRESS 



and will be mentioned only briefly here. The MID-PACIFIC Expedition 

 of 1950 in the eastern North Pacific, and the CAPRICORN Expedition 

 of 1952-1953 in the Central Pacific were principally geological and 

 geophysical in intent, studying the shape of the sea floor with the echo- 

 sounder, the character and depth of bottom sediments with bottom 

 samplers and by seismic refraction methods, and the transport of heat 

 through the sea floor with the bottom temperature probe. 



The NORTHERN HOLIDAY Expedition of 1951 in the eastern 

 North Pacific, the SHELLBACK Expedition of 1952 in the eastern Equa- 

 torial Pacific, and the TRANS-PACIFIC Expedition of 1953 in the deep 

 Bering Sea and the western and central North Pacific, were similar in 

 basic purpose. In each case the course was laid out to cross the major 

 current systems and to sample the principal water masses of the area. 

 In each case the major work of the expedition was a series of hydrogra- 

 phic stations at 60- to 90- mile intervals where temperature and salinity 

 were measured down to considerable depths, chemical analyses of water 

 samples made, and quantitative plankton tows carried out. Between 

 stations observations were made with the bathythermogiaph, geomagnetic 

 electro-kinetograph, echo-sounder and midwater trawl. Geological and 

 meteorological observations were also made on each expedition. 



An effort was made to cross the major circulation features at ap- 

 proximate right angles to facilitate velocity and transport computa- 

 tions. By means of water mass and isentropic analysis it will be possi- 

 ble to map out the distribution of water types and to study their origin 

 and subsequent transformation. In particular, the distribution of pro- 

 perties in deep water may cast some light on the little known inter- 

 mediate and deep circulation of the Pacific. The distributions of dis- 

 solved oxygen, phosphate and silicate and of planktonic species are 

 closely related to the distributions of conservative concentrations, and 

 the results of these expeditions will make possible a careful study of 

 this relationship. 



In summary, the results of these five expeditions should contribute 

 substantially to our knowledge of the major circulation and the distri- 

 butions of properties and organisms in the Pacific Ocean, An under- 

 standing of time and space variations in this general picture must await 

 the extension of phase three methods to deep-sea oceanography. 



