初期の地球におけるアビオティック窒素の減少
関連する実験動画
Updated: Jul 30, 2026

11:10
Conducting Miller-Urey Experiments
Published on: January 21, 2014
J A Brandes1, N Z Boctor, G D Cody
1Geophysical Laboratory, Carnegie Institution of Washington, DC 20015-1305, USA. brandes@gl.ciw.edu
Nature
|October 6, 1998
まとめ
鉱物触媒は,初期の地球条件下で窒素ガス (N2) をアンモニアに変換することができます. このプロセスは,生命の起源を助けるために,ハディアン海に不可欠なアンモニアを供給した可能性があります.
科学分野:
- 地質化学 地質化学
- 天体生物学 アストロバイオロジー
- ミネラロジーは,鉱物学です.
背景:
- 有機前駆物質の生産は,生命の起源にとって不可欠です.
- 窒素 (N2) は,アンモニアよりも有機合成の効率が低い.
- 初期の地球の還元条件は,アンモニアを好むと推定されていたが,実験的な証拠は欠けていた.
研究 の 目的:
- ミネラル触媒による窒素のアンモニアへの固定を実験的に調査する.
- 初期の地殻および水熱条件下でのアンモニア生産の可行性を決定する.
- 早期昏睡太陽パラドックスの解明におけるアンモニアの役割を評価する.
主な方法:
- N2,NO2,NO3をアンモニアに還元する鉱物触媒による実験.
- シミュレートされた地殻と海洋の水熱システム条件 (300800°C,0.10.4 GPa).
- 高温 (800°C以上) で窒素種の安定性の分析.
主要な成果:
- 300800°Cから0.10.4 GPaの間のN2,NO2-,およびNO3-から鉱物催化アンモニア合成が実証されています.
- N2だけが800°C以上で安定し,熱い蓄積過程で大気中のアンモニアの形成を制限することが判明した.
- 鉱物触媒によるN2減少が,ハデアン海へのアンモニアの潜在的重要な源として示されている.
結論:
- 鉱物触媒によるN2還元は,初期のハデアン海に重要なアンモニアを供給した可能性がある.
- 水熱アンモニア交換は大気アンモニアを供給し,早期の薄弱太陽パラドックスを解決することができた.
- この研究は,前生物化学と初期の地球大気条件におけるアンモニアの役割に対する実験的支持を提供します.
関連する概念動画
Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
Overview of Nitrogen Metabolism
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
Inorganic Nitrogen Assimilation
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme nitrate reductase...
Origin of Cellular Life
The origin of life on Earth is a complex and enigmatic event rooted in ancient biochemical processes and geological conditions. Experimental evidence supports the hypothesis that life began with the spontaneous formation of organic molecules such as RNA nucleotides, amino acids, and lipids under early Earth conditions. Factors like volcanic activity, intense UV radiation, and a reducing atmosphere without free oxygen likely facilitated these reactions. Hydrothermal vents on the ocean floor are...
Microbes and the Nitrogen Cycle
The nitrogen cycle is a complex biogeochemical process critical to maintaining the balance of nitrogenous compounds in ecosystems. This cycle involves multiple microbial-mediated transformations through which nitrogen changes oxidation states, supporting essential ecological functions and contributing to plant and microbial growth.Nitrogen Fixation and AmmonificationNitrogen fixation initiates the cycle by converting inert atmospheric nitrogen (N₂) into bioavailable ammonia (NH₃), a process...

