前例のない北極のツンドラの野火による炭素の損失
Michelle C Mack1, M Syndonia Bret-Harte, Teresa N Hollingsworth
1Department of Biology, University of Florida, PO Box 118525, Gainesville, Florida 32611, USA. mcmack@ufl.edu
Nature
|July 29, 2011
まとめ
北極のツンドラ火災は,かなりの量の炭素を放出し,世界の炭素バランスに影響を与えます. 気候変動による火災頻度の増加は,北極の緑化を相殺するポジティブなフィードバックループを生じさせる可能性がある.
科学分野:
- エコロジー エコロジー エコロジー
- 気候科学 気候科学
- 地質化学 地質化学
背景:
- 北極のツンドラ土壌は,膨大な量の古代の炭素を貯蔵しています.
- 火は歴史的に北極のツンドラでは滅多に発生していないが,気候変動により増加している.
- ツンドラ火災が炭素バランスに与える影響はほとんど不明である.
研究 の 目的:
- 大規模な北極のツンドラ火災による炭素の損失を定量化するために.
- 典型的な炭素交換と比較して,この損失の重要性を評価する.
- 北極の炭素予算と気候フィードバックへの影響を理解する.
主な方法:
- 2007年のアナクトゥヴク川の火災後のツンドラ生態系における炭素損失の分析.
- 土壌の有機物質の炭素損失を測定する.
- 年齢を決定するために残留土壌炭素の放射性炭素年代測定.
主要な成果:
- アナクトゥヴク川の火災により,炭素の損失は2,016 ± 435 g C m−2で,未干渉のツンドラよりも2倍の大きさです.
- 炭素の損失の60%は土壌の有機物質からであり,最大年齢は50年であった.
- 火災により約2.1テラグラムの炭素が放出され,これは毎年北極のツンドラで発生する炭素吸収量に匹敵する.
結論:
- トンドラの火災は,主に最近の土壌の有機物質から,かなりの炭素の損失を引き起こします.
- 気候変動によるツンドラ火災の頻度の増加は,重要なポジティブなフィードバックを表しています.
- このフィードバックは,北極の緑化に対抗し,ツンドラバイオームの純炭素バランスを変化させる可能性があります.
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