Pre-treatment methods for carbon and oxygen stable isotope ratio analysis of a Japanese white precious coral (Corallium konojoi)

Abstract

The aim of this study was to examine the necessary pre-processing methods for understand the habitat history of precious coral by using carbon and oxygen stable isotope ratios. The study was conducted on white corals (Corallium konojoi) collected off Hahajima Island, Ogasawara. A growth model was created using thin section images and EPMA mapping images, and powder subsamples were scraped along the annual ring structure. Organic material removal was verified with reference to previous studies and pre-treatment with a 10% hydrogen peroxide solution was carried out, followed by carbon-oxygen stable isotope ratio analysis.Anormal analysis values have obtained for the untreated samples and those pretreated as small pieces due to contamination by impurities such as organic matter. On the other hand, no such effects were observed in the pre-treated powder samples. There was no significant difference in the analyzed values between the untreated and pre-treated samples, and it can be said that the effect of pre-treatment on the analyzed values was minimal.