地上植物のメタン排出は,エアロビック条件下で発生する
Frank Keppler1, John T G Hamilton, Marc Brass
1Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany. frank.keppler@mpi-hd.mpg.de
Nature
|January 13, 2006
まとめ
科学者たちは,生きている植物が,酸素が豊富な環境でも,強力な温室効果ガスであるメタンを生成することを発見しました. このこれまでに未知の植物性メタン源は,世界のメタン予算と気候変動モデルに大きく影響を与える可能性があります.
科学分野:
- 環境科学 環境科学
- バイオジオケミストリー バイオジオケミストリー
- 植物生理学 植物生理学
背景:
- 大気中のメタンの濃度は,工業化以前の時代からほぼ3倍になり,気候に大きな影響を与えている.
- メタンは,大気化学,平流層オゾン,水蒸気に影響を与える重要な温室効果ガスです.
- 自然メタンの源は主に無毒環境における生物学的プロセスに起因する.
研究 の 目的:
- 陸上の植物の内部でメタン形成の未知の新しいプロセスを調査するために.
- 生きた植物や植物ゴミから生じるメタンの排出量を酸化条件下で定量化するために.
- この新しいメタン源が世界のメタン予算に及ぼす影響を評価する.
主な方法:
- 安定炭素同位体分析を使用して,メタンの形成経路を特定しました.
- 健全な植物と脱落した葉で実験室とフィールドでの化実験を行いました.
- 観測されたメタンの排出量をスケールして,グローバルソースの強さを推定した.
主要な成果:
- 陸上の植物が酸化条件下でメタンを素早くin situで形成することを実証した.
- 健全な植物と脱落した葉の両方からメタンの有意な排出が観察されました.
- 推定の世界的なメタン源濃度は,生きた植物から62~236Tg/年,植物のゴミから1~7Tg/年である.
結論:
- 生きた植物から生じる,これまで認識されなかった生物学的メタン源が特定されました.
- この植物ベースのメタンの生産は,世界のメタン予算に重大な影響を及ぼします.
- この発見は,天然のメタンの源と,過去の気候変動におけるメタンの役割を再検討することを必要としています.
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