まとめ
北極海のコアの研究は,15.7万年前の最後の脱氷期に溶けた水の流入が顕著であったことを明らかにしています. これは,氷床の変化や淡水輸出の増加を示し,7.2万年前に現代の北極海の条件を確立しました.
科学分野:
- パレオセアノグラフィー
- 気候科学 気候科学
- 北極の海洋学 北極の海洋学
背景:
- 過去の北極海の状況を理解することは,将来の気候変動を予測するために不可欠です.
- 最後の脱氷期 (Termination lb) は,地球上の氷床と海洋循環を大幅に変化させた.
研究 の 目的:
- 最後の脱氷期における北極海の中央部の古海洋学的条件を再構築する.
- 北極海への融水流入のタイミングと源を調査する.
- 現代の北極海の表面と深海の特徴がいつ確立されたかを決定する.
主な方法:
- 北極海の中央部の堆積物核からの酸素同位体記録の分析.
- 北極の同位体記録をフラム海峡とグリーンランド東部の大陸縁のデータと比較.
- 炭素同位体データを利用して,水の質量特性と生産性を理解する.
主要な成果:
- 最後の脱氷期 (15.7万年前) の初期に,北極海の中央部に溶けた水の大きなパルスが発生した証拠です.
- 同位体記録の並行傾向は,ユーラシア北極とグリーンランドの氷床の同期的な変化,または低塩分性の北極海水の輸出の増加を示唆しています.
- 現代の地表と深水の特徴の確立と,終結期lb (7.2千年前) の終わりまでに生産性の増加とともに季節的に氷のない条件.
結論:
- 最後の脱氷は,氷床のダイナミクスや海流の変化によって北極海に重大な水文学的変化を引き起こした.
- 北極海は,約720万年前に,特定の水質特性と生物学的生産性によって特徴づけられた,現代の状態に移った.
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