Variability of sea-ice conditions in the Fram Strait over the past 30,000 years
Variability of sea-ice conditions in the Fram Strait over the past 30,000 years
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DOI：
10.1038/ngeo665
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发表时间：
2009-11
影响因子：
18.3
通讯作者：
J. Müller;G. Massé;R. Stein;S. Belt
中科院分区：
文献类型：
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作者：
J. Müller;G. Massé;R. Stein;S. Belt
海冰是气候系统的重要组成部分：海冰覆盖率的变化影响极地地区的反照率，也影响深水形成的速度。北大西洋海冰覆盖的变化被认为与上一次冰川终止期间气候的突然变化有关，但重建海冰条件的情况很少。在这里，我们使用IP25和Brassicasterol生物标志物的沉积丰度，分别由与海冰相关的硅藻和开放水域浮游植物产生，以生成过去30,000年来最北端大西洋的海冰状况记录。我们的重建表明，在末次冰期期间，海冰覆盖和开阔海洋之间存在着一条静止的边缘，尽管在末次冰盛期的大部分时间里，常年的海冰覆盖占据了主导地位。大约14,000年前的早期变暖与无冰条件有关；然而，季节性海冰存在于整个全新世。我们发现海冰的记录与北欧海温相对较高的大西洋水流量的重建之间存在着时间上的联系。因此，我们得出结论，海冰状况的变化与区域和全球气候异常以及北大西洋的海洋环流有关。
Sea ice is a critical component of the climate system: variations in sea-ice cover affect the albedo of polar regions, and also the rate of deepwater formation,. Changes in the sea-ice cover of the North Atlantic Ocean are thought to have been related to abrupt climate changes throughout the last glacial termination, but reconstructions of sea-ice conditions are rare. Here we use the sedimentary abundance of the IP25and brassicasterol biomarkers, produced by sea-ice-associated diatoms and open-water phytoplankton, respectively, to generate a record of sea-ice conditions in the northernmost Atlantic Ocean for the past 30,000 years. Our reconstruction shows that a stationary margin between sea-ice cover and the open ocean existed during the Last Glacial, although perennial sea-ice cover prevailed for most of the Last Glacial Maximum. An early warming about 14,000 years ago was associated with ice-free conditions; however, seasonal sea ice was present throughout the Holocene. We find temporal links between our record of sea ice and reconstructions of the amount of relatively warm Atlantic water advected into the Nordic Seas,. We therefore conclude that changes in sea-ice conditions are linked to regional and global climate anomalies and oceanographic circulation in the North Atlantic.