JpGU-AGU Joint Meeting 2017

講演情報

[EE] ポスター発表

セッション記号 B (地球生命科学) » B-CG 地球生命科学複合領域・一般

[B-CG08] [EE] 深宇宙と深海から挑む生命探査科学

2017年5月23日(火) 15:30 〜 17:00 ポスター会場 (国際展示場 7ホール)

コンビーナ:矢野 創(宇宙航空研究開発機構・宇宙科学研究所)、Christophe Sotin(Jet Propulsion Laboratory)、高井 研(海洋研究開発機構極限環境生物圏研究センター)

[BCG08-P01] Microorganisms involved in the formation of distinctive iron oxide in deep-sea environments of Earth and even in extraterrestrial bodies

*牧田 寛子1,2菊池 早希子1光延 聖3Tanaka Emiko2,1Takaki Yoshihiro1山中 寿朗4土岐 知弘5Noguchi Takuroh6中村 謙太郎7Abe Mariko1Hirai Miho1Yamamoto Masahiro1Uematsu Katsuyuki8宮崎 淳一1布浦 拓郎1高橋 嘉夫7高井 研1 (1.独立行政法人 海洋研究開発機構、2.神奈川工科大学、3.愛媛大学、4.東京海洋大学、5.琉球大学、6.高知大学、7.東京大学、8.マリンワークジャパン)

It has been suggested that iron is one of the most important energy sources for photosynthesis-independent microbial ecosystems in the ocean crust of Earth. Iron-metabolizing chemolithoautotrophs play a key role as primary producers in anoxic-oxic interface environments, but little is known about their distribution and diversity, and ecological roles, particularly iron-oxidizers.
Recently, many iron-dominated flocculent sediments have been discovered at the deep-sea hydrothermal fields in the world. These sites are excellent place for studying iron-utilizing microbial communities and their mineralization of Fe-(oxy)hydroxides associated with deep-sea hydrothermal activities. Indeed, it is still unclear how such microbial populations are involved in iron-dominated flocculent deposit formation.
In this study, we analysed iron-dominated sediments from various deep-sea hydrothermal environments in the Western pacific by using culture-independent molecular techniques and X-ray mineralogical analyses. The SEM-EDS analysis and X-ray absorption fine structure (XAFS) analysis reveal chemical and mineralogical signatures of biogenic Fe-(oxy)hydroxides species as well as the potential contribution of iron-oxidizing bacteria to the in situ production. These key findings provide important insights into the mechanisms of both geomicrobiological iron cycling and formation of iron-dominated sediments in deep-sea hydrothermal fields. In addition, the formation and preservation mechanisms of biological produced iron-dominated sediments point to the possible microbial metabolisms and functions in the fossil records of iron oxide deposits such as banded iron formation (BIF) in the past Earth. Now, many peoples know that iron-oxide mineral deposits are also present in extraterrestrial bodies of our solar system such as Mars and Jupiter’s moon Europa. The formation mechanisms of these extraterrestrial iron-dominating mineral deposits are highly unknown. However, if in situ observations and sample-return-based analyses in future astrobiological exploration of these extraterrestrial red-orange deposits will find certain specific iron oxide structures such as helical, twisted and stringing shapes associated with organic materials, the specific iron oxide structures will be significant bio-markers and will be useful for further detail exploration planning and strategy.