Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS11] Aqua planetology

Tue. May 28, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Yasuhito Sekine(Earth-Life Science Insitute, Tokyo Institute of Technology), Tomohiro Usui(Earth-Life Science Institute, Tokyo Institute of Technology), Keisuke Fukushi(Institute of Nature & Environmental Technology, Kanazawa University), Takazo Shibuya(Japan Agency for Marine-Earth Science and Technology)

[MIS11-P10] Experimental study of abiotic nitrate reduction at a high temperature and high-pressure condition and implication for nitrogen chemistry in Hadean hydrothermal environments

*Manabu Nishizawa1, Takuya Saito1, Akiko Makabe1, Takazo Shibuya1, Ken Takai1 (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:prebiotic chemistry, nitrogen, deep sea hydrothermal vents

Nitrogen is an essential element for life as a major component of biomolecules and electron donor/acceptor for energy metabolism. Currently, nitrogen cycle in surface environments is mainly driven by biological processes including nitrogen fixation, nitrification and denitrification. In contrast, little is known about nitrogen cycle in the pre-biotic Earth and its relation to chemical evolution. This study focuses on nitrate chemistry during water-rock interaction in deep-sea hydrothermal environments to understand the fate of atmospherically-derived nitrate in the Hadean ocean. In experiments, artificial seawater with nitrate was reacted with synthetic komatiite at 350oC and 500 bar. Our experiments show that a substantial amount of nitrate was reduced to ammonium in an experimental condition. This implies that the Hadean deep-sea hydrothermal vents may have been favorable for chemical evolution in that both electron acceptor for energy metabolism (nitrate) and reduced nitrogen for organic synthesis (ammonium) were continuously supplied to the hydrothermal fluid-seawater mixing zone.