start-ver=1.4 cd-journal=joma no-vol=187 cd-vols= no-issue= article-no= start-page=106403 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=202508 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Nitrogen distribution and nitrogen isotope fractionation in synthetic 2:1 phyllosilicates under hydrothermal conditions at 200 °C and saturated vapor pressure en-subtitle= kn-subtitle= en-abstract= kn-abstract=This study investigates nitrogen distribution and isotope fractionation within synthetic 2:1 phyllosilicates, simulating submarine hydrothermal environments at 200 °C and saturated vapor pressure. XRD and EDS results revealed the potential coexistence of multiple cations in the interlayer of synthetic 2:1 phyllosilicate, concurrently suggesting cation substitution in the tetrahedral and/or octahedral sheets. Meanwhile, the iron-enriched 25-5 sample exhibited restricted interlayer expansibility. NH4+ absorptions were identified in the NH4-stretching (3200–2800 cm−1) and NH4-bending (1450–1400 cm−1) regions, with wavenumber shifts indicating the influence of interlayer water removal. At pH 10.56, over 95% of nitrogen was released into the gas phase, while at pH 8.88, nitrogen proportions in the liquid and gas phases were comparable (average 48–49%). Experiments with iron at pH ∼8.80 showed that the nitrogen proportion in the gas phase (average 28%) was more than twofold lower than that in the liquid phase (average 68%). Equilibrium isotope fractionation factors indicated discernible preference for heavier nitrogen isotopes in the solid phase (αsolid-liquid = 1.009–1.021 and αsolid-gas = 1.011–1.027). The αliquid-gas range for sample 25–2 was 1.001–1.008, while that for the iron-enriched composite 25–5 was 0.997–1.010. Our experimental studies have confirmed that, in the absence of exchange interactions with external substances possessing different nitrogen isotope ratios, nitrogen isotope fractionation between ammonium and ammonia, controlled by variations in temperature and pH during mineralization, plays a crucial role in the variation of nitrogen isotope ratios. Additionally, we confirmed that metal-amines influence nitrogen isotope fractionation by modulating ammonia gas emission. These findings enhance our understanding of nitrogen cycling across the gas, liquid, and solid phases in submarine hydrothermal systems. en-copyright= kn-copyright= en-aut-name=JoJaeguk en-aut-sei=Jo en-aut-mei=Jaeguk kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YamanakaToshiro en-aut-sei=Yamanaka en-aut-mei=Toshiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyoshiYouko en-aut-sei=Miyoshi en-aut-mei=Youko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SuzukiMasaya en-aut-sei=Suzuki en-aut-mei=Masaya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KuwaharaYoshihiro en-aut-sei=Kuwahara en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ChibaHitoshi en-aut-sei=Chiba en-aut-mei=Hitoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=LeeBum Han en-aut-sei=Lee en-aut-mei=Bum Han kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Research Institute for Geo-Resources and Environment, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST) kn-affil= affil-num=4 en-affil=Research Institute for Geo-Resources and Environment, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST) kn-affil= affil-num=5 en-affil=Department of Environmental Changes, Faculty of Social and Cultural Studies, Kyushu University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=8 en-affil=Critical Minerals Research Center, Korea Institute of Geoscience & Mineral Resources (KIGAM) kn-affil= en-keyword=Synthetic 2:1 phyllosilicates kn-keyword=Synthetic 2:1 phyllosilicates en-keyword=Nitrogen distribution kn-keyword=Nitrogen distribution en-keyword=Nitrogen isotope fractionation kn-keyword=Nitrogen isotope fractionation en-keyword=Hydrothermal system kn-keyword=Hydrothermal system END start-ver=1.4 cd-journal=joma no-vol=83 cd-vols= no-issue=4 article-no= start-page=841 end-page=848 dt-received= dt-revised= dt-accepted= dt-pub-year=2003 dt-pub=20038 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Sulphur-isotopic composition of the deep-sea mussel Bathymodiolus marisindicus from currently active hydrothermal vents in the Indian Ocean en-subtitle= kn-subtitle= en-abstract= kn-abstract=

Sulphur-isotopic composition of soft tissues from bathymodiolus marisindicus collected from hydrothermal vents in the indian ocean was reported. the [delta]34s values of the soft tissues (+3[similar]+5‰ vs cañyon diablo troilite) were nearly identical to those from the associated hydrothermal fluid and chimney sulphides (+5 to +8‰), but were significantly different from that of the common seawater sulphate (+21‰), which suggested that the endosymbiotic bacteria used sulphide in the fluid as an energy source. transmission electron microscopic observation of the endosymbionts also suggested that the symbiont is a thioautotroph. bathymodiolus species, which depend on either sulphide or methane oxidation, or both, have a worldwide distribution. bathymodiolus marisindicus from the indian ocean has a close relationship with congeners in the pacific ocean as evidenced by form of symbiosis. biogeography and migration of the genus bathymodiolus based on the relevant data are briefly discussed.

en-copyright= kn-copyright= en-aut-name=YamanakaToshiro en-aut-sei=Yamanaka en-aut-mei=Toshiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MizotaChitoshi en-aut-sei=Mizota en-aut-mei=Chitoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=FujiwaraYoshihiro en-aut-sei=Fujiwara en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ChibaHitoshi en-aut-sei=Chiba en-aut-mei=Hitoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HashimotoJun en-aut-sei=Hashimoto en-aut-mei=Jun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=GamoToshitaka en-aut-sei=Gamo en-aut-mei=Toshitaka kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=OkudairaTakamoto en-aut-sei=Okudaira en-aut-mei=Takamoto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil= kn-affil=University of Tsukuba affil-num=2 en-affil= kn-affil=Iwate University affil-num=3 en-affil= kn-affil=Japan Marine Science and Technology Center affil-num=4 en-affil= kn-affil=Okayama University affil-num=5 en-affil= kn-affil=Japan Marine Science and Technology Center, Tokyou affil-num=6 en-affil= kn-affil=Hokkaido University affil-num=7 en-affil= kn-affil=Osaka City University END