スペレオテームは,シベリアの永久凍土の50万年の歴史を明らかにしています
A Vaks1, O S Gutareva, S F M Breitenbach
1Department of Earth Sciences, University of Oxford, Oxford, UK. anton.vaks@earth.ox.ac.uk
Science (New York, N.Y.)
|February 23, 2013
まとめ
永久凍土の土壌は,かなりの量の炭素を貯蔵しています. シベリアの洞窟でのスペレオテム年代測定は,地球温暖化がわずかに上昇したとしても,広範囲の永久凍土地帯が解凍され,炭素の放出に影響を与える可能性があることを明らかにしています.
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
- 永久凍土科学 永久凍土科学とは
- 地質化学 地質化学
背景:
- 永久凍土地域は膨大な量の土壌炭素を貯蔵し,地球気候と北緯度の環境に影響を与えます.
- 気候温暖化に対する永久凍土の反応を理解することは極めて重要ですが,長期的な変化は直接観測能力を超えています.
研究 の 目的:
- 過去の気候状態を使用して,シベリアの永久凍土の歴史を再構築する.
- 異なる氷期間の条件下で永久凍土の融解の値を評価する.
主な方法:
- スペレオテムの成長期は,シベリアの洞窟の南北横断で日付付けられました.
- スペレオテムの成長は,過去の氷河期間の気候条件と相関していた.
主要な成果:
- スピレオテムの成長は,研究されたすべての洞窟で,完全な氷河間期間にのみ観察されました.
- 最も北端の洞窟 (60°N) は,海洋同位体ステージ11以降の成長を示さなかった.
- 海洋同位体第11段階の成長は,適度な温暖な気候下での永久凍土の大きな解凍を示しています.
結論:
- 氷期間の条件は,現在のよりわずかに暖かい場合でも,広範囲にわたる永久凍土の融解を誘導するのに十分です.
- 過去のスプレオテム記録は,永久凍土の長期的な動態と気候フィードバックに関する重要な洞察を提供します.
関連する概念動画
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
01:27Microbes and Climate Change
Microorganisms are pivotal agents in Earth's biogeochemical cycles, significantly influencing climate dynamics through their metabolic activities. These microbes modulate the levels of key greenhouse gases by both contributing to and helping mitigate climate change.Microbial Contributions to Greenhouse Gas EmissionsRising global temperatures accelerate microbial metabolism, which, in turn, speeds up the decomposition of organic matter. This process releases carbon dioxide (CO₂) through...
01:29Diversity of Archaea IV
Hyperthermophilic archaea are a group of extremophiles thriving at temperatures above 80°C, often in hydrothermal vents and volcanic soils where conditions surpass the boiling point of water. At such temperatures, proteins, membranes, and DNA in most organisms degrade, but hyperthermophiles have evolved remarkable adaptations to maintain stability and function.Unique Cellular FeaturesHyperthermophilic membranes are composed of a monolayer of biphytanyl tetraether lipids, which resist thermal...
02:56The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
01:25Microbial Mats
Microbial communities forming biofilms and mats represent complex, spatially structured ecosystems where metabolic processes are stratified according to light, oxygen, and nutrient gradients. Biofilms are initial colonization stages, only a few millimeters thick, while mature microbial mats can reach centimeter-scale thickness and display intricate vertical organization. Their structural and functional heterogeneity allows microorganisms to occupy distinct ecological niches within a few...
01:27Factors Influencing Microbial Growth: Temperature
Microorganisms display remarkable adaptations, enabling them to thrive in diverse ecological niches across a wide range of temperatures. Temperature profoundly influences microbial growth by affecting enzymatic activity, membrane fluidity, and other cellular processes.Each microorganism operates within a specific temperature range defined by three cardinal points: minimum, optimum, and maximum. Below the minimum temperature, membranes lose fluidity, halting transport processes. Above the...