最後の氷河間期における深海
J C Duplessy1, D M Roche, M Kageyama
1Laboratoire des Sciences du Climat et de l'Environnement/Institut Pierre Simon Laplace (LSCE/IPSL), CNRS/Université de Versailles Saint Quentin (CEA/CNRS/UVSQ), Parc du CNRS, 91198 Gif sur Yvette, France. Jean-Claude.Duplessy@lsce.cnrs-gif.fr
まとめ
過去の氷河期の間,北大西洋深水 (NADW) はより暖かかった. 日焼けによって引き起こされるこの海洋温暖化は,西南極の氷床の融解に寄与したのかもしれない.
科学分野:
- パレオセアノグラフィー
- 気候科学 気候科学
- 海洋学 海洋学とは
背景:
- 深海の気温は,過去の気候動態に関する重要な洞察を提供します.
- 過去の氷河期間の理解は,将来の気候変動を予測するのに役立ちます.
- 北大西洋深水 (NADW) と南極底水 (AABW) は,世界の海洋循環の重要な構成要素です.
研究 の 目的:
- 最後の氷河期間の深海の温度を再構築するために.
- 観測された深海の温度変化の要因を調査するために.
- これらの温度変化が南極の氷床に与える潜在的な影響を評価する.
主な方法:
- 深海のコアから採取したベンシックフォラミニフェラの酸素同位体分析.
- 大西洋と南洋のコアの分析.
- 仮説を検証するための海洋モデルシミュレーション.
主要な成果:
- 北大西洋の深い水域 (NADW) は,最後の氷河間期に今日と比較して0.4°C暖かかった.
- 南極底水 (AABW) の温度は変わらない.
- モデルシミュレーションは,NADW温暖化のための強制メカニズムとして,高緯度の日焼けが示されています.
結論:
- 海洋温暖化は,特に北大西洋では,太陽照射の変化によって引き起こされました.
- NADWの温暖化により,南極海への熱が移った可能性が高い.
- この熱伝達は,最後の氷河期間の西南極の氷床の部分的な融解に寄与した可能性がある.
関連する概念動画
What is an Ecosystem?
Overview
Global 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.
The 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...
Diversity of Protists III
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
Marine Microbial Ecology
Marine microbial ecosystems are shaped by distinct physicochemical limits, including high salinity, low nutrient availability, and fluctuating oxygen levels. These conditions favor smaller microbial cell sizes, which maximize their surface-to-volume ratio for efficient nutrient uptake.Microbial activity and community composition are closely linked to biogeochemical cycles, particularly in dynamic environments like estuaries, where halotolerant microbes thrive in response to variable salinity...
Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...


