北極の微生物は,CO2よりも高いUV-B放射線に反応する
David Johnson1, Colin D Campbell, John A Lee
1Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK. D.Johnson@Shef.ac.uk
Nature
|March 8, 2002
まとめ
紫外線B (UV-B) 放射線と二酸化炭素 (CO2) の増加は,亜北極の熱帯で土壌の微生物群を大幅に変化させた. これらの発見は,UV-Bが敏感な極地生態系にわずかな環境影響を与えるという考えに異議を唱える.
科学分野:
- エコロジー エコロジー エコロジー
- 環境科学 環境科学
- 微生物学 微生物学とは
背景:
- オゾン層の減少と,化石燃料の燃焼による大気中の二酸化炭素 (CO2) の増加による地表紫外線B (UV-B) 放射線の上昇は,敏感な極地生態系に影響します.
- 極地植物のコミュニティは,栄養素の循環のために土壌の微生物に依存しており,それらは土壌の炭素 (C) と窒素 (N) に不可欠です.
- 以前の仮定では,UV-Bが土壌の微生物バイオマスに与える影響は限られているが,地下における炭素配分の増加によるCO2の増加により,より強い影響が期待されている.
研究 の 目的:
- 強化されたUV-B放射線と上昇したCO2が,亜北極の熱帯における土壌の微生物バイオマスとコミュニティ構造に及ぼす影響を調査する.
- 炭素と窒素 (C:N) の比率と細菌コミュニティの組成に対するUV-BとCO2の組み合わせた影響を評価する.
主な方法:
- サバークティック熱帯の生態系を5年間,強化されたUV-B放射線と高濃度のCO2に実験的に暴露した.
- 土壌サンプルを分析して,C:N比率と細菌群の構造の変化を決定する.
主要な成果:
- 5年間,高紫外線 (UV-B) 放射線を単独でも,高濃度のCO2と併用しても,土壌の微生物バイオマスに重大な変化をもたらした.
- 観察された主な変化は,土壌のC:N比率と細菌コミュニティの構造の大きな変化です.
結論:
- 強化されたUV-B放射線は,小規模な環境問題に関する以前の考えに反して,土壌の微生物バイオマスと細菌コミュニティの構造に大きな影響を及ぼします.
- この調査結果は,オゾン層の減少とUV-Bの増加が,特に脆弱な極地地域において,生態学的に重大な影響を及ぼすことを強調しています.
- 高濃度のCO2はUV-Bの影響と相互作用し,地球規模の変化の原動力に対する土壌生態系の複雑な反応を強調する可能性がある.
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