ローレンチド氷床の脱氷過程における土壌炭素の動態
まとめ
北米の氷床の融解は,土壌の炭素収縮につながった. 泥炭地帯の炭素吸収は継続していますが,人間のCO2排出量と比較して,天然の土壌の炭素貯蔵率は小さいです.
科学分野:
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 土壌科学 土壌科学は,土壌の科学である.
- 炭素循環に関する研究
背景:
- ローランタイド氷床の脱氷により,北アメリカの広大な地域が露出しました.
- 新しく露出した土壌は,大気中の炭素を吸収する可能性がある.
- 過去の炭素収縮の動態を理解することは,将来の炭素予算を予測する上で極めて重要です.
研究 の 目的:
- ローレンティド氷床の脱氷後の土壌における有機炭素の結合のタイミングと速度を調査する.
- 脱氷した泥炭地帯における進行中の炭素吸収を評価する.
- 天然の土壌の炭素収縮率と人為的な二酸化炭素生産を比較する.
主な方法:
- 地質学および土壌記録の分析により,土地の露出と炭素蓄積の時間軸を決定する.
- 放射性炭素年代測定法により,土壌の発達と炭素埋葬の時間表を確立する.
- 土壌の有機炭素含量と堆積環境に基づいて,炭素収縮率の推定.
主要な成果:
- 最も急速な陸地曝露は1万2千年から8千年前に起こった.
- 土壌の炭素収縮率が最も高いのは,8,000~4,000年前に観測された.
- 泥炭地帯における炭素吸収は継続的なプロセスであり,安定した状態はまだ達成されていません.
結論:
- 脱氷は北米で土壌の有機炭素を大量に吸収するようになった.
- 土壌の天然の炭素収縮は重要ですが,現在,人為的なCO2排出量によって追い越されています.
- 泥炭地帯の炭素動態の継続的なモニタリングは,現代の炭素循環を理解するために不可欠です.
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