南極付近の温帯雨林 クレタ紀の暖かい時期
Johann P Klages1, Ulrich Salzmann2, Torsten Bickert3
1Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany. Johann.Klages@awi.de.
Nature
|April 3, 2020
まとめ
クレタ紀中期の暖かさは南緯82度で温帯雨林を支えており,南極の氷河は存在しなかったことを示している. これは 植生された地表が 高い二酸化炭素レベルであっても 惑星を大幅に冷却することを示唆しています
科学分野:
- 古代気候学
- 古植物学
- 堆積地質学
背景:
- クレータ紀中期は,大気中の二酸化炭素 (CO2) が千分の100万分の1の量で,非常に暖かい時期でした.
- この温暖な期間の極地氷の存在は,南極圏の南にある地質学的記録が限られているため,議論の余地があります.
研究 の 目的:
- 南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏の南極圏
- 高CO2条件下での極地の氷の存在を判断する.
主な方法:
- 西南極のシェルフの沈殿物の分析,最も南の白亜紀の記録.
- 堆積物の中の化石の根,花粉,そして胞子の検査.
- 気候モデルのシミュレーションで,古気候条件を再構築する.
主要な成果:
- トゥロニアン・サントニアン (92~8300万年前) の南緯82度にある温帯低地熱帯雨林の発見.
- 化石記録には 3メートルの長さの 化石の根のネットワークが含まれています
- 気候モデルによると この温帯気候には 1120~1680ppmの二酸化炭素と 氷のない南極の植生が必要でした
結論:
- 温帯の熱帯雨林は 暖かい白亜紀中期に 南極の高緯度で繁栄しました
- この発見は この時期の大規模な南極氷河が 存在しなかったことを示唆している.
- 植生は気候に大きく影響し,高CO2でもアルベドによって温暖化効果を相殺する.
関連する概念動画
Global Climate Change
28.4K
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.
28.4K
What is Climate?
20.3K
Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, “Climate is what you expect. Weather is what you get.” Climate is influenced by geographic factors, such as latitude, terrain, and proximity to bodies of water.
20.3K
Diversity of Archaea III
257
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like...
257
Responses to Heat and Cold Stress
14.5K
Every organism has an optimum temperature range within which healthy growth and physiological functioning can occur. At the ends of this range, there will be a minimum and maximum temperature that interrupt biological processes.
14.5K
The Fossil Record
26.9K
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...
26.9K
Adaptations that Reduce Water Loss
27.7K
Though evaporation from plant leaves drives transpiration, it also results in loss of water. Because water is critical for photosynthetic reactions and other cellular processes, evolutionary pressures on plants in different environments have driven the acquisition of adaptations that reduce water loss.
27.7K


