Silicon-32 profiles in the South Pacific

Abstract

Si and ³²Si were collected from samples of up to 375,000 ℓ of seawater using an in-situ extraction technique with ferric-hydroxide-loaded natural sponges contained in "butterfly" samplers. Results of measurements of dissolved ³²Si and stable silicon in three vertical profiles in the South Pacific (23°-21°S; 175°E-177°W) are compared with ³²Si specific activities observed in shallow and deep-water siliceous sponges collected from the Pacific, and with theoretical calculations of the ³²Si production rate in the atmosphere by cosmic radiation. Good agreement exists between the production rate, the fallout rate, and the ³²Si oceanic inventory of (2±0.5)×10⁻² (dpm/cm²) obtained from the South Pacific profiles.