11:30 AM - 11:45 AM
[AOS13-09] The stepwise acid dissolution for large fish otoliths using a new apparatus
Keywords:otolith, fish migration, migration history, stepwise acid dissolution method
Fish otoliths are calcium carbonate crystals and have been used to analyse as a recorder of habitat change. This is because once crystallised, they do not undergo metabolism and thus retain the environment in which they were formed, as represented by trace element ratios and isotope ones. This formation creates a layered structure in an otolith, which is older on the inside and newer on the outside.
The stepwise acid dissolution method (Yokoyama et al., 2000; Kubota et al., 2015) is known for analysing otoliths to understand the migration history of fish. Sequential dissolution of an otolith is conducted and carbon dioxide produced in the reaction vessel is collected separately and they are reduced to graphite (Yokoyama et al., 2022) that can be measured by Accelerator Mass Spectrometry (AMS: Yokoyama et al., 2019). This method is validated to be efficient to reveal migration histories of fish (Ando et al., in prep.).
However, there was a size limitation to be applied this method due to reaction speed and limitation for graphitizing apparatus, the stepwise acid dissolution method has so far been applied mainly to otoliths of relatively small size. In this study, we designed a new apparatus for conducing the stepwise acid dissolution method to otoliths larger than 2 cm. Using this newly designed apparatus, we found that the the step -wise dissolution can be applied for larger samples to understand migration history of fish that has large otolith.
The stepwise acid dissolution method (Yokoyama et al., 2000; Kubota et al., 2015) is known for analysing otoliths to understand the migration history of fish. Sequential dissolution of an otolith is conducted and carbon dioxide produced in the reaction vessel is collected separately and they are reduced to graphite (Yokoyama et al., 2022) that can be measured by Accelerator Mass Spectrometry (AMS: Yokoyama et al., 2019). This method is validated to be efficient to reveal migration histories of fish (Ando et al., in prep.).
However, there was a size limitation to be applied this method due to reaction speed and limitation for graphitizing apparatus, the stepwise acid dissolution method has so far been applied mainly to otoliths of relatively small size. In this study, we designed a new apparatus for conducing the stepwise acid dissolution method to otoliths larger than 2 cm. Using this newly designed apparatus, we found that the the step -wise dissolution can be applied for larger samples to understand migration history of fish that has large otolith.