気候システムへの土壌温暖化と炭素サイクルフィードバック
J M Melillo1, P A Steudler, J D Aber
1The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA. jmelillo@mbl.edu
Science (New York, N.Y.)
|December 14, 2002
まとめ
森林における土壌の温暖化は,土壌の炭素が限られているため,小さな,一時的な二酸化炭素の放出を引き起こします. しかし,窒素の供給量の増加は植物の成長を促進し,土壌の炭素損失を相殺し,気候モデルに挑戦する可能性があります.
科学分野:
- 森林生態学 森林生態学とは
- 土壌科学 土壌科学
- 気候変動に関する研究
背景:
- 土壌の炭素と窒素の循環は,森林の生態系と地球気候にとって非常に重要です.
- 温度上昇がこれらのサイクルに与える影響を理解することは,正確な気候モデリングに不可欠です.
研究 の 目的:
- 中緯度の硬木林における炭素と窒素の循環に対する土壌温暖化の長期的な影響を調査する.
- これらの変化が気候システムに及ぼす影響を評価する.
主な方法:
- 10年にわたる土壌温暖化実験は,中緯度の硬木林で実施されました.
- 測定は,土壌の有機物質の腐敗,二酸化炭素の流れ,鉱物窒素の利用可能性に焦点を当てた.
主要な成果:
- 土壌の温暖化は,土壌の有機物質の分解と二酸化炭素排出の加速につながったが,その影響は小さく,一時的であった.
- 不安定な土壌の炭素プールが限られているため,温暖化反応は制限された.
- 温暖化により,植物にミネラル窒素の供給が増加した.
結論:
- 温暖化が土壌に排出する炭素への影響は,炭素の可動性が限られているため,予想以上に重要ではない.
- 窒素の供給量が増加すると,植物の成長が刺激され,バイオマスにおける炭素吸収が増加する可能性があります.
- この発見は,森林の温暖化による土壌炭素の長期的損失を予測する気候モデルに異議を唱えている.
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