北極のツンドラの生態系における炭素貯蔵は,長期の栄養素肥料化によって減少しています
Michelle C Mack1, Edward A G Schuur, M Syndonia Bret-Harte
1Department of Botany, University of Florida, Gainesville, Florida 32611, USA. mcmack@ufl.edu
Nature
|September 24, 2004
まとめ
地球温暖化が北部の生態系に影響を及ぼしている. ツンドラの肥料を20年に渡って研究したところ,栄養素の増加は土壌の炭素を大幅に失い,気候温暖化を増幅していることが明らかになった.
科学分野:
- 北極のエコロジー
- 気候変動科学 気候変動科学
- 土壌科学 土壌科学
背景:
- 高緯度の地域では,地球温暖化が拡大している.
- 北部の生態系は,世界の土壌炭素の大部分を貯蔵しています.
- 温暖化に対する生態系の炭素バランス反応を理解することは極めて重要です.
研究 の 目的:
- アラスカのツンドラの炭素バランスに対する栄養素の供給量の増加による長期的な影響を調査する.
- 温暖化による栄養素の放出が生態系の炭素貯蔵に与える影響を評価する.
主な方法:
- アラスカのツンドラで20年間の受精実験が行われました.
- 測定には,植物生産,分解率,土壌の炭素/窒素動態などが含まれていた.
- 温暖化に対するツンドラ生態系の反応の概念モデルが利用されました.
主要な成果:
- 20年間の実験で,地上植物の年間生産量は2倍になりました.
- 植物バイオマスの増加にもかかわらず,平方メートルあたり約2,000グラムの炭素の生態系損失が発生しました.
- 深い土壌層からの大量炭素と窒素の損失は,植物バイオマスとゴミの増加を相殺する.
結論:
- ツンドラ生態系における栄養素の供給量の増加は,生態系の炭素の純損失につながる可能性があります.
- 温暖化に起因する土壌栄養素の放出は,土壌から炭素の放出を拡大する可能性があります.
- このポジティブなフィードバックループは,さらに気候変動を加速させることができます.
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