黒海の微生物のサンゴ礁は,メタンの無酸素酸化によって作動しています
Walter Michaelis1, Richard Seifert, Katja Nauhaus
1Institute of Biogeochemistry and Marine Chemistry, University of Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany. michaelis@geowiss.uni-hamburg.de
Science (New York, N.Y.)
|August 10, 2002
まとめ
ブラック海のメタンの浸出地にある微生物マットは,メタンの炭素をバイオマスと炭酸塩に組み込む. これらのアーカイアとバクテリアのコンソーシアムは,炭酸の降水とバイオマスの蓄積を駆動し,地球に影響を及ぼします.
科学分野:
- ゲオミクロバイオロジー
- バイオジオケミカルサイクル
- マリンサイエンス マリンサイエンス・サイエンス
背景:
- 巨大な微生物マットは,無酸素の黒海シェルフ水域のメタン浸出で繁栄します.
- これらのマットは,広範囲にわたる炭酸塩の蓄積を形成し,高さ4メートルに達します.
- 以前の研究では,炭酸塩の形成における微生物活動の役割が強調されています.
研究 の 目的:
- 炭酸塩の降水と黒海メタン漏れで生体質の蓄積を促す微生物のプロセスを調査する.
- 微生物マットと関連する炭酸塩に組み込まれた炭素の源を決定する.
- これらのプロセスが古代の炭素循環に及ぼす影響を理解する.
主な方法:
- 古代生物 (ANME-1) と硫酸塩を減少させる細菌 (Desulfosarcina/Desulfococcus) を中心に微生物マットの組成を分析した.
- 炭素の組み込みを追跡するための安定同位体分析 (13C減少)
- メタン (AOM) の無酸素酸化と硫酸縮小を観察するためのインビトロインキュベーション実験.
主要な成果:
- 13Cの大幅な減少は,炭酸塩,バイオマス,脂質にメタン炭素の組み込みを確認しています.
- 微生物マットは,ANME-1アーカイアとDesulfosarcina/Desulfococcusバクテリアによって支配されています.
- 実験室内インキュベーションでは,これらの微生物コンソーシアムが硫酸還元と結合したメタンの無酸素酸化を実行することを実証しました.
結論:
- メタン浸出における無酸素微生物のコンソーシアムは,炭酸塩の降水と重要なバイオマス生産の両方を誘発することができる.
- これらの発見は,無酸素環境における炭素循環機構の洞察を提供します.
- この研究は,地球の地質学的な過去における同様のプロセスを理解するための意味を持つ.
関連する概念動画
01:15Metabolism of Chemolithotrophs
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation. However, because inorganic electron donors...
01:25Microbial Mats
Microbial communities forming biofilms and mats represent complex, spatially structured ecosystems where metabolic processes are stratified according to light, oxygen, and nutrient gradients. Biofilms are initial colonization stages, only a few millimeters thick, while mature microbial mats can reach centimeter-scale thickness and display intricate vertical organization. Their structural and functional heterogeneity allows microorganisms to occupy distinct ecological niches within a few...
01:26Microbes and Methanogenesis
Methanogenesis is a critical microbial process in anaerobic ecosystems responsible for the biological production of methane, a potent greenhouse gas and valuable biofuel. This metabolic pathway is primarily facilitated by methanogenic archaea, which thrive in anoxic environments such as wetlands, sediments, and animal gastrointestinal tracts. The absence of oxygen in these habitats prevents aerobic respiration, thereby favoring alternative biochemical pathways for organic matter degradation.In...
01:30Marine Microbial Ecology
Marine microbial ecosystems are shaped by distinct physicochemical limits, including high salinity, low nutrient availability, and fluctuating oxygen levels. These conditions favor smaller microbial cell sizes, which maximize their surface-to-volume ratio for efficient nutrient uptake.Microbial activity and community composition are closely linked to biogeochemical cycles, particularly in dynamic environments like estuaries, where halotolerant microbes thrive in response to variable salinity...
01:18Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...
01:27Microbes and Climate Change
Microorganisms are pivotal agents in Earth's biogeochemical cycles, significantly influencing climate dynamics through their metabolic activities. These microbes modulate the levels of key greenhouse gases by both contributing to and helping mitigate climate change.Microbial Contributions to Greenhouse Gas EmissionsRising global temperatures accelerate microbial metabolism, which, in turn, speeds up the decomposition of organic matter. This process releases carbon dioxide (CO₂) through...