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Natural variability of the Arctic Ocean sea ice during the present interglacial [Earth, Atmospheric, and Planetary Sciences]
Proceedings of the National Academy of Sciences of the United States of America ( IF 11.1 ) Pub Date : 2020-10-20 , DOI: 10.1073/pnas.2008996117
Anne de Vernal 1 , Claude Hillaire-Marcel 1 , Cynthia Le Duc 1 , Philippe Roberge 1 , Camille Brice 1 , Jens Matthiessen 2 , Robert F. Spielhagen 3 , Ruediger Stein 2, 4
Affiliation  

The impact of the ongoing anthropogenic warming on the Arctic Ocean sea ice is ascertained and closely monitored. However, its long-term fate remains an open question as its natural variability on centennial to millennial timescales is not well documented. Here, we use marine sedimentary records to reconstruct Arctic sea-ice fluctuations. Cores collected along the Lomonosov Ridge that extends across the Arctic Ocean from northern Greenland to the Laptev Sea were radiocarbon dated and analyzed for their micropaleontological and palynological contents, both bearing information on the past sea-ice cover. Results demonstrate that multiyear pack ice remained a robust feature of the western and central Lomonosov Ridge and that perennial sea ice remained present throughout the present interglacial, even during the climate optimum of the middle Holocene that globally peaked ∼6,500 y ago. In contradistinction, the southeastern Lomonosov Ridge area experienced seasonally sea-ice-free conditions, at least, sporadically, until about 4,000 y ago. They were marked by relatively high phytoplanktonic productivity and organic carbon fluxes at the seafloor resulting in low biogenic carbonate preservation. These results point to contrasted west–east surface ocean conditions in the Arctic Ocean, not unlike those of the Arctic dipole linked to the recent loss of Arctic sea ice. Hence, our data suggest that seasonally ice-free conditions in the southeastern Arctic Ocean with a dominant Arctic dipolar pattern, may be a recurrent feature under “warm world” climate.



中文翻译:

当前冰间期[地球,大气和行星科学]期间北冰洋海冰的自然变化

确定并密切监测持续的人为变暖对北冰洋海冰的影响。但是,它的长期命运仍然是一个悬而未决的问题,因为它在百年至千禧年时间尺度上的自然变异性尚未得到充分的记录。在这里,我们使用海洋沉积记录来重建北极海冰波动。对沿洛蒙诺索夫海岭从北格陵兰延伸至拉普捷夫海的北冰洋收集的岩心进行了放射性碳测年,并对其微古生物学和孢粉学含量进行了分析,两者均具有过去海冰覆盖的信息。结果表明,多年充填冰仍然是罗蒙诺索夫山脊西部和中部的重要特征,并且在整个当前冰期之间,多年生海冰仍然存在,即使在全球全新的中部全新世的最佳气候时期(约6500年前)。相反,东南部的罗蒙诺索夫山脊地区至少在大约4,000年前经历了季节性的无海冰条件。它们的特征是浮游植物的生产力较高,海底的有机碳通量较高,导致生物碳酸盐的保存量较低。这些结果表明,北冰洋的东西表面海况形成了对比,这与最近北极海冰流失有关的北极偶极子情况不同。因此,我们的数据表明,在北冰洋东南部具有极地北极偶极格局的季节性无冰条件可能是“温暖世界”气候下的复发特征。东南罗蒙诺索夫海岭地区至少在大约4,000年前经历了季节性无海冰的情况,至少是零星的。它们的特征是浮游植物的生产力较高,海底的有机碳通量较高,导致生物碳酸盐的保存量较低。这些结果表明,北冰洋的东西表面海况形成了对比,这与最近北极海冰流失有关的北极偶极子情况不同。因此,我们的数据表明,在北冰洋东南部具有极地北极偶极格局的季节性无冰条件可能是“温暖世界”气候下的复发特征。东南罗蒙诺索夫海岭地区至少在大约4,000年前经历了季节性无海冰的情况,至少是零星的。它们的特征是浮游植物的生产力较高,海底的有机碳通量较高,导致生物碳酸盐的保存量较低。这些结果表明,北冰洋的东西表面海况形成了对比,这与最近北极海冰流失有关的北极偶极子情况不同。因此,我们的数据表明,在北冰洋东南部具有极地北极偶极格局的季节性无冰条件可能是“温暖世界”气候下的复发特征。它们的特征是浮游植物的生产力较高,海底的有机碳通量较高,导致生物碳酸盐的保存量较低。这些结果表明,北冰洋的东西表面海况形成了对比,这与最近北极海冰流失有关的北极偶极子情况不同。因此,我们的数据表明,在北冰洋东南部具有极地北极偶极格局的季节性无冰条件可能是“温暖世界”气候下的复发特征。它们的特征是浮游植物的生产力较高,海底的有机碳通量较高,导致生物碳酸盐的保存量较低。这些结果表明,北冰洋的东西表面海况形成了对比,这与最近北极海冰流失有关的北极偶极子情况不同。因此,我们的数据表明,在北冰洋东南部具有极地北极偶极格局的季节性无冰条件可能是“温暖世界”气候下的复发特征。

更新日期:2020-10-20
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