強化された炭素ポンプは,氷河海における栄養素制限の緩和から推測される
L E Pichevin1, B C Reynolds, R S Ganeshram
1School of Geosciences, Grant Institute, University of Edinburgh, West Main Road, EH10 3JW, Edinburgh, UK. laetitia.pichevin@ed.ac.uk
Nature
|June 26, 2009
まとめ
東方赤道太平洋の鉄の肥料は,氷河期の間,一次生産性を高めました. これにより,生物学的炭素ポンプが強化され,大気中の二酸化炭素レベルを下げるのに役立ちました.
科学分野:
- パレオセアノグラフィー
- バイオジオケミストリー バイオジオケミストリー
- 海洋地質学 海洋地質学
背景:
- 東方赤道太平洋 (EEP) は大気中の炭素の重要な供給源である.
- 現代のEEPのプライマリ生産性は,シリシウム酸と鉄によって制限され,炭素の輸出を妨げています.
- 氷河からの鉄の供給により,生産性と炭素の輸出が増加し,CO2が減った可能性がある.
研究 の 目的:
- 氷河の二酸化炭素排出におけるEEPの役割を調査する.
- ダイアトムのシリカと炭素の吸収に対する鉄の肥料の影響を明らかにする.
- 氷河の炭素循環の動態に対するEEPの貢献を再評価する.
主な方法:
- EEPからの新しいシリコン同位体記録の分析.
- シリコンと窒素の同位体変化の調査.
- 有機炭素埋葬とオパール蓄積率の解釈.
主要な成果:
- 新しいシリコンイソトープ記録は,氷河期EEPのダイアトームによる炭素へのシリコンの吸収の減少を示唆しています.
- このパラドックスは,塵からの鉄の供給量の増加によって説明される.
- 氷河期のEEPの生産性は,鉄,シリコン,窒素によって制限されませんでした.
結論:
- EEPは,最後の氷河期中に活性化された生物学的炭素ポンプを持っていた可能性が高い.
- この改良されたポンプは,大気中の二酸化炭素の排出に寄与した.
- の制限は,低緯度海における氷河生物学的炭素ポンプを制限している可能性があります.
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