From the deep-sea hydrothermal vents and cold seeps ecosystems, more than 600 species containing many endemic species have been discovered. The deep-sea mussels of the genus Bathymodiolus are dominant species at deep-sea hydrothermal vents and cold seeps throughout the world. They are known to rely on the nutrients produced by the chemosynthetic symbiont in their gills. In 2009, we found a colony of bathymodiolin mussels at a hydrothermal vent of Myojinsho (Myojin Reef), which is a hardly investigated area. Myojinsho lies in the northern segment of the Izu-Ogasawara (Bonin) Arc and had been volcanically active until recently. We collected specimens from the colony using a remotely operated vehicle. We identified them as Bathymodiolus aduloides by morphological observation and phylogenetic analyses using mitochondrial DNA sequencing. We could not find any other species of mussels during the dive. This result is interesting because this species has not been discovered from hydrothermal vents in this region; the dominant species in this region, including the neighbouring Myojin Knoll Caldera, is B. septemdierum.

The crystallinity, electrical, and optical properties of the ferroelectric/fluorescent oxide structures using sol-gel-derived (Ba0.6Sr0.4)TiO3 (BST) and (Sr0.8Eu0.2)Bi2.2Ta2O9 (Eu-SBT) grown on STO(110) single crystal substrates were introduced for the first time. In the present structures, the SBT films partly included a (116)-oriented Eu-SBT crystallite. The polarization vs. voltage characteristics of the BST/Eu-SBT structures showed the hysteresis loop caused by spontaneous polarization reversal, and then several emission peaks from Eu3+ ion were observed in a photoluminescence spectrum of a present BST/Eu-SBT structure.