地質学的な二酸化炭素吸収源として北極における有機炭素の侵食
Robert G Hilton1, Valier Galy2, Jérôme Gaillardet3
1Department of Geography, Durham University, South Road, Durham DH1 3LE, UK.
Nature
|August 7, 2015
まとめ
北部の土壌は 古代の炭素を貯蔵しています 川の浸食によって炭素が運ばれ,長期にわたる地質学的二酸化炭素の吸収源となる可能性があり,マッケンジー川が重要な役割を果たしている.
科学分野:
- 地化学
- 北極科学
- 気候科学
背景:
- 高緯度の土壌は 千年もの間 相当量の炭素を貯蔵しています
- 永久凍土は土壌から有機炭素を放出し 二酸化炭素 (CO2) を排出します
- 浸食により土壌の有機炭素が河川に流れ込み,海洋堆積物の中に長期にわたって蓄積される可能性があります.
研究 の 目的:
- マッケンジー川の微粒子有機炭素 (POC) の源,流量,運命を定量化するために.
- マッケンジー川が北極海の炭素排出量に 与える影響を評価する
- 地質学的な二酸化炭素吸収源に 侵食された高緯度土壌の炭素が 寄与しているかどうかを判断する.
主な方法:
- 放射性炭素年代測定で POCの年齢を判定する
- 安定した炭素同位体と元素の比率は,生物圏と岩石由来のPOCを区別する.
- POCの含有量と堆積量の分析により,POCの流れが計算される.
主要な成果:
- マッケンジー川の侵食された生物圏 POC は古代であり,平均放射性炭素年齢は5,800 ± 800年である.
- マッケンジー川からの計算された生物圏のPOCフローは,年間2.2 ((+1.3) ((-0.9) テラグラムの炭素です.
- このPOCの流れは,シリケート気象による盆地のCO2排出量の3倍です.
結論:
- マッケンジー川は 古代の侵食された陸上の有機炭素を 効率的に北極海に運びます
- オーガニック・カーボンの効率的な埋葬は,ホロセンの間の海洋沈殿物で,重要な地質学的CO2の沈殿を示唆しています.
- 高緯度の土壌の侵食は北極の炭素循環の 重要な要素ですが 制限が不足しています
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