The eastern Pacific is characterized by records from Urvina Bay and Wenman islands in the Galapagos. Two records, one from Nauru Island and the other from Guadalcanal, characterize the western Pacific. The north Pacific is characterized by a record from Hawaii, and the south Pacific by a record from Raratonga. All records show the ocean response to the invasion of bomb-radiocarbon, although the timing of the peak and the magnitude of the peak vary systematically about the ocean basin. The peak at the western Pacific sites is intermediate between the subtropical and eastern tropical sites.
All records show significant interannual variability during the bomb era.
This conclusion was reached 10 years earlier by Taro Takahashi in an unpublished report using sparse time series measurements of radiocarbon from flask samples. The general timing of the peaks at different locations can best be explained by the delay in transport of water from subduction in the subtropics to the upwelling region in the eastern tropics. The western Pacific sites can best be explained as a mixture of subtropical and eastern tropical sources. This conclusion was also reached by Takahashi. More detailed study is necessary to describe in more detail exactly how and where mixing occurs in the upwelling system, although sheer produced by the tropical undercurrent is likely to be of central importance.