Bomb 14C in the Indian Ocean measured by accelerator mass spectrometry: oceanographic implications

Abstract

AMS 14C measurements on samples collected in the tropical-equatorial Indian Ocean are presented and compared with β-counting results. The most significant observation is a doubling of the bomb-14C inventory and mean penetration depth in the equatorial zone. Based on hydrologic considerations, two hypotheses can be proposed: 1) direct influx of Pacific mid-latitude waters through the Indonesian archipelago; and 2) advection and/or mixing with Mode Water from the southern gyre of the Indian Ocean. Results obtained with a general circulation model of the ocean suggest that the influx from the Pacific is important in the upper 300 m and that below 500 m the bomb-14 budget is dominated by Mode Water advection. -from Authors