Wegwerth Antje, Arz Helge W, Kaiser Jérôme, Winckler Gisela, Lembke-Jene Lester, Rigalleau Vincent, Ruggieri Nicoletta, Sadatzki Henrik, Lamy Frank
Marine Geology, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany.
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA.
Nat Commun. 2025 Jul 17;16(1):6593. doi: 10.1038/s41467-025-62037-w.
The Antarctic Circumpolar Current (ACC) is a major driver of global ocean circulation and climate. To better understand the interplay between long-term atmospheric and ocean variability in the Southern Ocean since the late Miocene, we present sea surface temperature (SST) and carbonate preservation records from the Subantarctic Eastern South Pacific (IODP Site U1543), along with an extended ACC strength record from Central South Pacific Site U1541. We focus on long-term eccentricity-scale variations showing decreased (increased) SST with enhanced (reduced) CaCO preservation, and stronger (weaker) ACC strength, particularly during the Pliocene. These changes coincide with stronger (weaker) South Pacific SST gradients, possible northward (southward) migration of Southern Ocean fronts, strengthened (weakened) westerlies, and atmospheric CO release. These patterns contrast with Pleistocene glacial-interglacial cycles. Reduced Pacific-Atlantic exchange through the Drake Passage may have weakened Atlantic Meridional Overturning Circulation during warming at Site U1543 across the intensification of Northern Hemisphere Glaciation. Simultaneous stronger ACC and higher CaCO deposition in the high-latitude Pacific suggest a strengthened basin-wide Pacific overturning circulation during parts of the Pliocene.
南极绕极流（ACC）是全球海洋环流和气候的主要驱动力。为了更好地理解自中新世晚期以来南大洋中长期大气和海洋变化之间的相互作用，我们展示了来自亚南极东南太平洋（综合大洋钻探计划U1543站点）的海面温度（SST）和碳酸盐保存记录，以及来自中南太平洋U1541站点的延长的ACC强度记录。我们关注长期偏心率尺度的变化，这些变化表现为随着碳酸钙保存增强（减弱），海面温度降低（升高），以及ACC强度增强（减弱），特别是在上新世期间。这些变化与更强（更弱）的南太平洋SST梯度、南大洋锋面可能向北（向南）移动、西风增强（减弱）以及大气中二氧化碳释放相吻合。这些模式与更新世冰期 - 间冰期循环形成对比。在U1543站点变暖期间，随着北半球冰川作用的加剧，通过德雷克海峡的太平洋 - 大西洋交换减少，可能削弱了大西洋经向翻转环流。上新世部分时期，高纬度太平洋地区同时出现更强的ACC和更高的碳酸钙沉积，表明整个太平洋盆地的翻转环流得到加强。
