北大西洋の深海の酸素化の変化 中期のプレイストセンの移行期
Nicola C Thomas1, Harold J Bradbury1, David A Hodell1
1Department of Earth Science, University of Cambridge, Cambridge, UK.
まとめ
大西洋の奥深くでは 氷河期に酸素濃度が大幅に低下し 二酸化炭素の貯蔵に影響を与えました この研究は 気候の変化を理解するために 過去の海洋酸化を再構築します
科学分野:
- 古代海洋学
- 海洋地化学
- 気候科学
背景:
- 海洋の酸素濃度と大気中の二酸化炭素 (pCO2) は,海洋の炭素循環によって結びついている.
- 深海の有機炭素再鉱化が溶けた無機炭素の貯蔵と酸素レベルに影響する.
研究 の 目的:
- 過去150万年の北大西洋の酸素濃度を再構築する
- 中期プレイストセンの移行期における海洋の脱酸素化,氷の量,大気中のpCO2との関係を調査する.
主な方法:
- パレオ酸素の代理として,ベンシックフォラミニフェラ (epifaunal vs. infaunal) の高解像度炭素同位体グラデントを使用した.
- 北大西洋の深海の酸素濃度の相対的な変化を再構築した.
主要な成果:
- 約9万~9万年前に大西洋の氷河の深海の酸素化が著しく減少したと記録されている.
- 大陸の氷の量が増加し 海洋熱ハリン循環が変化しました
- 結果は深海の酸素の減少,呼吸による炭素の蓄積の増加,氷河によるpCO2の減少を示しています.
結論:
- 氷河期におけるより低い深海の酸素モデルを支持する.
- 深海での炭素貯蔵の増加は,大気中のpCO2の減少に寄与したと考えられます.
- これらの発見は,中期プレイストセンの移行期における海洋気候のフィードバックに関する洞察を提供します.
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