冰川事件的淡水北冰洋被厚厚的冰架覆盖
Walter Geibert1, Jens Matthiessen2, Ingrid Stimac2
1Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany. walter.geibert@awi.de.
Nature
|February 4, 2021
概括
证据显示,在广泛的冰架下,北极有两个主要的淡水间隔,影响了过去的海洋状况和海平面记录. 这挑战了以前对北极冰川历史的解释.
科学领域:
- 古海洋学是古海洋学.
- 海洋地质学海洋地质学
背景情况:
- 早期的假设建议过去的北极冰架,由海底水平侵蚀特征支持.
- 海洋沉积物记录缺乏在冰川时期广泛存在北极冰架的明确证据.
研究的目的:
- 为广泛的北极冰架和淡水间隔提供直接的海洋沉积物证据.
- 调查这些事件的时间和对北冰洋条件的影响.
- 为了解释-230记录和沉积率中的异常.
主要方法:
- 分析海洋沉积物核心的同位素特征,特别是-230.
- 石灰质纳米化石的表征,包括Emiliania huxleyi.
- 水文流量估计和边界状况分析.
主要成果:
- 证据表明至少有两个主要的北极淡水间隔与广泛的冰架存在相吻合.
- 这些间隔的约会为70,000-62,000年前 (海洋同位素阶段4) 和150,000-131,000年前 (海洋同位素阶段6).
- 对-230记录中普遍存在的最小值的解释,解决约会差异.
结论:
- 北极海洋被冰架覆盖,并在特定的冰川时期充满了淡水.
- 这些事件涉及大约900万立方公里的淡水,挑战了现有的海平面重建.
- 在短时间内,大量的淡水释放到北大西洋是合理的.
更多相关视频
13:38Laser-Induced Fluorescence Emission L.I.F.E. as Novel Non-Invasive Tool for In-Situ Measurements of Biomarkers in Cryospheric Habitats
Published on: October 26, 2019
8.2K
08:16Ice Generation and the Heat and Mass Transfer Phenomena of Introducing Water to a Cold Bath of Brine
Published on: March 13, 2017
14.2K
相关概念视频
Global Climate Change
28.0K
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.
28.0K
Phase Transitions: Melting and Freezing
14.0K
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...
14.0K
Green Algae
400
Green algae, also referred to as chlorophytes, are different from red algae in having the chloroplasts containing chlorophylls a and b, which give them their distinct green hue. However, they lack phycobiliproteins, preventing them from developing the red or blue-green pigmentation seen in red algae. In terms of photosynthetic pigment composition, green algae closely resemble plants and share a close evolutionary relationship with them. Taxonomically Green algae belong to Phylum Chlorophyta in...
400
The Water Cycle
27.5K
The Earth’s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, the cycling of water is extremely important to ecosystem dynamics.
27.5K
Isothermal Processes
4.4K
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
4.4K
Surface Appendages of Archaea
389
Archaeal surface appendages are highly specialized structures essential for environmental adaptation, encompassing roles in adhesion, biofilm formation, and motility. Among these appendages, pili and archaella stand out for their distinct morphologies and functionalities, enabling archaea to thrive in diverse and often extreme environments.Pili: Adhesion and Biofilm FormationPili are filamentous structures assembled from pilin protein subunits, primarily contributing to adhesion and biofilm...
389
