世界海に有機炭素を埋めるネオゲン
Ziye Li1,2,3, Yi Ge Zhang4, Mark Torres5
1College of Marine Geosciences, Key Laboratory of Submarine Geosciences and Prospecting Techniques, Ocean University of China, Qingdao, China.
Nature
|January 4, 2023
まとめ
海洋沈殿物の有機炭素埋葬は 気候の重要な調節因子で かつて考えられていたより大きな変動を示しました ミオセンの中期には 埋葬が抑制され 過去の地球温暖化が 増幅された可能性があります
科学分野:
- 古代海洋学
- 地化学
- 気候科学
背景:
- 海洋有機炭素の埋葬は 大気中のCO2と酸素の供給源として重要な役割を果たします
- 過去の有機炭素埋葬率を推定するための従来の方法は,重大な不確実性を持つ質量バランス計算に依存しています.
研究 の 目的:
- 質量バランス方法から独立して,有機炭素埋葬率を計算するための新しい"ボトムアップ"アプローチを開発し,適用する.
- 世界的なデータを用いて,ネオゲン期 (23-3万年) の有機炭素埋葬の歴史を再構築する.
主な方法:
- オーガニックカーボン埋葬率を計算するために,世界各地の81のサイトからデータを利用しました.
- 伝統的な質量バランス計算から独立した新しい方法論を用いた.
- 有機と無機の炭素の分析された炭素同位体値 (δ13C).
主要な成果:
- オーガニック・カーボン埋葬率の空間時間的な変動が 予想より大きいことが明らかになった.
- 初期ミオセーンとプレオセーンで高い埋葬率を特定し,ミオセンの半ばで最も低い割合を記録した.
- ミオセンの中期に最も低い有機炭酸埋葬比率を観測し,モンテレー仮説に反した.
結論:
- 温度に依存する細菌の分解に関連したミオセンの抑制された有機炭素埋葬は,有機炭素循環が地球温暖化に肯定的なフィードバックとして作用することを示唆しています.
- この研究は 過去の炭素循環の動態と 気候への影響について より堅実な理解を提供します
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