東部熱帯太平洋の進化は,プレオ・プレイストセンの氷河期を経て起こった
Kira T Lawrence1, Zhonghui Liu, Timothy D Herbert
1Department of Geological Sciences, Brown University, Box 1846, Providence, RI 02912, USA. kira_lawrence@brown.edu
Science (New York, N.Y.)
|April 8, 2006
まとめ
恒久的なエルニーニョのような気候状態は,海洋の温暖化予算の変化により,300万年前に終わりました. 東部熱帯太平洋の冷却と生産性の変化は,プレオ・プレイストセーン全体を通して,世界の氷の量変化を追跡した.
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
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
背景:
- 熱帯太平洋における恒久的なエルニーニョのような状態は,およそ300万年前に終わったと推測されています.
- この気候の変化は,北半球の大規模な氷床の出現と,海洋の熱予算の再編成と一致しました.
研究 の 目的:
- 過去500万年の東赤道太平洋 (EEP) の過去の気候条件を再構築する.
- EEPの海面温度 (SST) と生産性に対する熱線変化,海洋熱予算,温室効果ガス,軌道変動の影響を調査する.
主な方法:
- EEP条件の高解像度アルケノン再構築.
- 海面温度 (SST) の分析と生物学的生産性の記録.
主要な成果:
- 北半球氷河期の激化が,プレオ・プレイストセーン期のEEPの単調な冷却を止めることはできませんでした.
- EEP SSTと生産性は,41,000年の偏斜周波数で支配的な世界的な氷の量変化と相変化を示した.
- 南半球の変化は,観測された気候の変動を調節する可能性が高い.
結論:
- EEPは,主要な氷河期イベントにもかかわらず,過去500万年にわたって継続的な冷却を経験しました.
- 熱帯太平洋の気候の動態は,地球規模の氷の量,特に傾斜周期と強く結びついていた.
- 南半球の影響は,これらの熱帯気候の変化を調節する上で重要な役割を果たしました.
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.
01:07Speciation Rates
Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.
02:39Gene Flow
Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.
02:35What is Evolutionary History?
Scientists record evolutionary history by analyzing fossil, morphological, and genetic data. The fossil record documents the history of life on Earth and provides evidence for evolution. However, both fossil and living organisms offer evidence that outlines Earth’s evolutionary history.Phylogenetic trees illustrate the evolutionary relationships among these organisms. Scientists infer organisms’ common ancestry by evaluating shared morphological and genetic characteristics. Together, the fossil...
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...
02:39Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...