How does the Southern Ocean palaeoenvironment during Marine Isotope Stage 5e compare to the modern?
How does the Southern Ocean palaeoenvironment during Marine Isotope Stage 5e compare to the modern?
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DOI：
10.1016/j.marmicro.2021.102066
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发表时间：
2021-11-10
影响因子：
1.9
通讯作者：
Hillenbrand, C-D
中科院分区：
文献类型：
--
作者：
Chadwick, M.;Allen, C. S.;Hillenbrand, C-D
海洋同位素阶段（MIS） 5e （130-116 ka）是理解未来人为变暖可能活跃的气候反馈和响应的重要“过程模拟”。重建MIS 5e期间的南大洋（SO）古环境，并将其与现在的环境进行比较，可以深入了解南大洋各部门对气候变暖的不同反应。本文介绍了7个MIS 5e海洋沉积物岩心的新记录及其表层沉积物记录；所有岩心均位于南纬55度以南。我们研究了硅藻种类组合的变化及其伴随的海面温度、冬季海冰范围（WSIE）和冰川融水通量的变化。所有记录都表明，在MIS 5e期间，相对于地表沉积物，WSIE变暖了。虽然太平洋和印度扇区的记录在整个MIS 5e期间显示出非常稳定的条件，但大西洋扇区的记录显示出更多的变化条件，特别是在WSIE方面。这些变化的条件归因于威德尔海的冰山和冰川融水通量增加。在MIS 5e期间，威德尔海的冰山和冰川融水通量增加的证据可能对了解西南极冰盖的稳定性具有重要意义，无论是在MIS 5e期间还是在未来变暖的情况下。
Marine Isotope Stage (MIS) 5e (130-116 ka) represents an important 'process analogue' for understanding the climatic feedbacks and responses likely active under future anthropogenic warming. Reconstructing the Southern Ocean (SO) palaeoenvironment during MIS 5e and comparing it to the present day provides insights into the different responses of the SO sectors to a warmer climate. This study presents new records from seven marine sediment cores for MIS 5e together with their surface sediment records; all cores are located south of 55 degrees S. We investigate changes in diatom species assemblage and the accompanying variations in sea surface temperatures, winter sea-ice extent (WSIE) and glacial meltwater flux. All records show warmer conditions and a reduced WSIE during MIS 5e relative to the surface sediments. While the Pacific and Indian Sector records present very stable conditions throughout MIS 5e, the Atlantic Sector records display much more changeable conditions, particularly with respect to the WSIE. These variable conditions are attributed to higher iceberg and glacial meltwater flux in the Weddell Sea. This evidence for increased iceberg and glacial meltwater flux in the Weddell Sea during MIS 5e may have significant implications for understanding the stability of the West Antarctic Ice Sheet, both during MIS 5e and under future warming.