[Raman and FTIR characteristics of otolith of ornamental carp].

Otolith is a typical natural biomineral as functional deposit existing in teleost's ears, which is mainly composed of calcium carbonate and organic matter. There is a pair of lapillus, sagitta and asteriscus in fish's inner ear, respectively. The authors compare the asteriscus and lapillus in cultured ornamental carp using FTIR and Raman. The result shows that the mineral phase in lapillus is aragonite, while the mineral phase in asteriscus is vaterite. The pure aragonite and vaterite existing respectively in otolith are of importance as being used as sample to study aragonite/vaterite biomineralization mechanism. Compared with inorganic induced aragonite and vaterite using FTIR and Raman, the authors found that the spectra of aragonite in lapillus are between those of inorganic induced aragonite and other bio induced aragonite; while the spectra of vaterite in asteriscus are similar to those of other bio induced vaterite. It is possible that unstable vaterite was stabilized through the organic effects in biomineralization process.