南大洋の深海の炭素の輸出は,天然の鉄の肥料化によって強化された
Raymond T Pollard1, Ian Salter, Richard J Sanders
1National Oceanography Centre Southampton, Natural Environment Research Council and University of Southampton, European Way, Southampton SO14 3ZH, UK.
Nature
|January 30, 2009
まとめ
南洋における天然の鉄の肥料化は,植物プランクトンの開花を大幅に促進し,深海への炭素の輸出を増加させます. この自然なプロセスは,人工鉄添加よりも,炭素の結合をより効果的に強化します.
科学分野:
- 海洋学 海洋学とは
- マリン・バイオジオケミストリー
- 気候科学 気候科学
背景:
- 高栄養低塩素 (HNLC) 地域は,鉄の利用可能性によって制限されています.
- これらの地域での植物プランクトンの開花は,大気中の二酸化炭素を吸収します.
- 鉄の天然肥料が長期にわたって炭素を吸収する効率を高める効果はよくわかっていない.
研究 の 目的:
- 南洋における天然鉄の受精が植物プランクトンに与える影響と炭素の輸出を調査する.
- クロゼット諸島の近くの鉄誘発型植物プランクトン・グラデーションが有機炭素の流れを増大させるという仮説を検証するためである.
- 海洋の様々な深さで毎年発生する粒子炭素の流れを定量化するために.
主な方法:
- クロゼット天然鉄受精実験 (CROZEX) を実施しました.
- 表面,深さ3km,そして海底で測定された粒子炭素の流れ.
- 自然に鉄で受精したHNLC地域と非受精したHNLC地域間の炭素フローを比較した.
主要な成果:
- 炭素の流れは,自然に鉄が受精した地域では,受精されていないHNLC地域と比較して2-3倍高かった.
- CROZEXの封じ込め効率は,人工的に誘発された開花よりも大幅に高く,他の自然開花よりも低いものでした.
- 研究結果は,氷河からの鉄の供給の増加が,深海への炭素の輸出を増大させたことを示唆している.
結論:
- 南極亜大陸南洋における天然鉄の肥料化により,炭素の輸出が大幅に増加する.
- 鉄の供給は,海洋の炭素収縮を調節する上で重要な役割を果たします.
- 異なる自然鉄受精イベント間の封じ込め効率の不一致を理解するためにさらなる研究が必要です.
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