Concentration and isotope ratio of ammonia in ancient oceans

• Project/Area Number: 15H03741
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: NISHIZAWA Manabu 国立研究開発法人海洋研究開発機構, 深海・地殻内生物圏研究分野, 研究員 (60447539)
• Co-Investigator(Kenkyū-buntansha): 渋谷 岳造 国立研究開発法人海洋研究開発機構, 深海・地殻内生物圏研究分野, 研究員 (00512906)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000); Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000); Fiscal Year 2016: ¥8,580,000 (Direct Cost: ¥6,600,000、Indirect Cost: ¥1,980,000); Fiscal Year 2015: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000)
• Keywords: アンモニア / 濃度 / 窒素同位体比 / 古海洋 / 初期海洋 / 太古代 / 海洋 / 白雲母 / 雲母 / 熱水変質岩 / 年代 / 窒素同位体

Outline of Final Research Achievements

Though ammonia is a key reactant for the synthesis of cellular materials, ammonia concentrations in the early oceans are largely unknown. The purpose of this study is to reconstruct ammonia concentrations in the early oceans from that in minerals in Archean oceanic crusts. We have newly developed the methodologies for separation of tiny minerals from archean basalts and for quantification of concentrations and isotope ratios of ammonium in separated minerals at the nanomole level. We find that the separated minerals preserve ammonium in seawater origin. Experiments for water-rock interaction in the presence of ammonium also support that oceanic crusts preserve ammonium in seawater origin.

Research Products

• [Journal Article] Long-Term Cultivation and Metagenomics Reveal Ecophysiology of Previously Uncultivated Thermophiles Involved in Biogeochemical Nitrogen Cycle (2018)
  • Author(s): Kato, S., Sakai, S., Hirai, M., Tasumi, E., Nishizawa, M., Suzuki, K. and Takai, K.
  • Journal Title: Microbes and Environments Volume: 33 Issue: 1 Pages: 107-110
  • DOI: 10.1264/jsme2.ME17165
  • NAID: 130006581753
  • ISSN: 1342-6311, 1347-4405
  • Peer Reviewed / Open Access
• [Journal Article] Recycled Archean sulfur in the mantle wedge of the Mariana Forearc and microbial sulfate reduction within an extremely alkaline serpentine seamount (2018)
  • Author(s): Aoyama Shinnosuke、Nishizawa Manabu、Miyazaki Junichi、Shibuya Takazo、Ueno Yuichiro、Takai Ken
  • Journal Title: Earth and Planetary Science Letters Volume: 491 Pages: 109-120
  • DOI: 10.1016/j.epsl.2018.03.002
  • Peer Reviewed
• [Journal Article] Removal of organic contaminants from iron sulfides as a pretreatment for mineral-mediated chemical synthesis under prebiotic hydrothermal conditions (2017)
  • Author(s): Nishizawa, M., Saitoh, M., Matsui, Y., Usui, Y. and Shibuya, T.
  • Journal Title: Geochemical Journal Volume: 印刷中
  • NAID: 130006243143
  • Peer Reviewed
• [Presentation] 天体衝突による大気の酸化仮説:後期太古代の地質記録による検証 (2017)
  • Author(s): 斎藤 誠史,黒澤 耕介,臼井 洋一,奥村 知世,尾上 哲治,佐藤 峰南,石田 湧也,渋谷 岳造,西澤 学,松井 洋平,澤木 佑介,佐藤 友彦,上野 雄一郎
  • Organizer: 日本地球化学会第64回年会
• [Presentation] The evolution of Nitrogen Fixation Metabolism (2016)
  • Author(s): Nishizawa, M.
  • Organizer: 18th Annual Meeting of the Society of Evolutionary Studies, Japan
  • Place of Presentation: Tokyo Institute of Technology (Meguro-ku, Tokyo)
  • Year and Date: 2016-08-26
  • Int'l Joint Research / Invited