The radiocarbon concentration (Δ14C) in coral skeletons is a unique tracer for investigating the ocean circumstances and global carbon cycle, because corals record the past Δ14C changes in the dissolved inorganic carbon of the surrounding surface seawater during the skeletal accretion. Coral Δ14C dataset with a high-temporal resolution make it possible to understand seasonal cycles of horizontal advections of the ocean, together with CO2 exchanges between atmosphere and ocean over the last several decades to centuries.
We have developed a simple and effective method for CO2 extraction for AMS 14C measurements. Conventional sample preparation methods for corals are time-consuming because two procedures are required; sampling of small aliquots from coral sample and reaction of these portions with acid. Moreover, sampling using a microdrill or a microsaw system cannot avoid some loss of samples. Newly developed system in our laboratory made the procedure more precise and convenient as one step using a CO2 laser heating in helium gas flow. Furthermore, there is a potential to improve the sampling resolution obtained by conventional method (0.5-1 mm, in general). We report the system configuration and experimental procedures as well as the results on assessments of blank and isotope fractionation induced during the CO2 extraction.
See more of Poster Session II
See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)