Lamont-Doherty Earth Observatory (LDEO), Columbia University, Palisades, NY 10964, USA.
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. Bermuda Institute of Ocean Sciences, St. George's, Bermuda.
Science. 2016 Jul 29;353(6298):470-4. doi: 10.1126/science.aaf5529. Epub 2016 Jun 30.
The most recent ice age was characterized by rapid and hemispherically asynchronous climate oscillations, whose origin remains unresolved. Variations in oceanic meridional heat transport may contribute to these repeated climate changes, which were most pronounced during marine isotope stage 3, the glacial interval 25 thousand to 60 thousand years ago. We examined climate and ocean circulation proxies throughout this interval at high resolution in a deep North Atlantic sediment core, combining the kinematic tracer protactinium/thorium (Pa/Th) with the deep water-mass tracer, epibenthic δ(13)C. These indicators suggest reduced Atlantic overturning circulation during every cool northern stadial, with the greatest reductions during episodic Hudson Strait iceberg discharges, while sharp northern warming followed reinvigorated overturning. These results provide direct evidence for the ocean's persistent, central role in abrupt glacial climate change.
最近的冰期以快速和半球不同步的气候振荡为特征，其起源仍未解决。海洋经向热输送的变化可能导致了这些反复的气候变化，在海洋同位素阶段 3 期间最为明显，这是 25000 到 60000 年前的冰川间隔期。我们在北大西洋深海沉积物岩芯中以高分辨率研究了整个间隔期间的气候和海洋环流示踪剂，将运动示踪剂钍/钕（Pa/Th）与深水团示踪剂、底栖δ(13)C 结合起来。这些指标表明，在每个寒冷的北方冰期，大西洋翻转环流都会减少，而在哈德逊海峡冰山排放的间歇性事件中减少幅度最大，而在翻转环流重新活跃之后，北方会出现急剧变暖。这些结果为海洋在突然的冰川气候变化中持续的核心作用提供了直接证据。
