近日，美国普林斯顿大学Sarah Shackleton团队研究了过去300万年的全球海洋热含量。该研究于2026年3月18日发表在《自然》杂志上。

更新世以全球气候变冷以及冰期旋回强度与持续时间的增加为特征。这一时期区域表层和次表层海洋温度记录呈现不同趋势，表明纬向和经向热量输送及大洋环流发生了动态变化。这些差异趋势也使得确定总海洋热含量演变的努力复杂化。

该研究通过分析南极艾伦山蓝冰区浅层冰芯中的惰性气体（Xe/Kr），提供了过去300万年平均海洋温度的记录。由于地层复杂性，这些记录无法重建单个冰期旋回，可能代表冰期与间冰期条件的加权平均。尽管如此，研究组发现与上新世-更新世转型期（约270万年前）大致同期出现显著降温，而中更新世转型期（120万至80万年前）温度保持稳定。与近期全球海表温度汇编的比较显示，长期降温趋势基本一致，但在上新世-更新世和中更新世转型期存在重要差异。

研究组认为这些时期海表温度与平均海洋温度的不同趋势，与深层水形成和上升流变化引起的地表与次表层热量再分配有关。通过解卷积底栖有孔虫δ¹⁸O记录，该温度记录还可估算300万至50万年前的全球冰量变化，并揭示中更新世转型期前后存在冰盖扩张增强阶段。

附：英文原文

Title: Global ocean heat content over the past 3 million years

Author: Shackleton, Sarah, Hishamunda, Valens, Yan, Yuzhen, Carter, Austin, Morgan, Jacob, Severinghaus, Jeff, Aarons, Sarah, Marks-Peterson, Julia, Epifanio, Jenna, Buizert, Christo, Brook, Edward, Kurbatov, Andrei V., Bender, Michael L., Higgins, John

Issue&Volume: 2026-03-18

Abstract: The Pleistocene epoch was characterized by global cooling and an increase in the intensity and duration of glacial cycles. Regional surface and subsurface ocean temperature records follow distinct trends over this interval, suggesting dynamic changes in zonal and meridional heat transport and ocean circulation. These differing trends also complicate efforts to determine the evolution of total ocean heat content. Here we provide a record of mean ocean temperature over the past 3 million years from noble gas (Xe/Kr) measurements in shallow ice cores recovered in the Allan Hills blue ice area, Antarctica1. The stratigraphically complex records preclude reconstruction of individual glacial cycles and probably represent a weighted averaging of glacial and interglacial conditions2. Nonetheless, we find pronounced cooling roughly coincident with the Plio-Pleistocene Transition (around 2.7million years ago), and steady temperatures across the Mid-Pleistocene Transition (1.2 to 0.8million years ago). Comparisons with a recent global sea surface temperature compilation3 show broad consistency in long-term cooling but important differences at the Plio-Pleistocene and Mid-Pleistocene transitions. We suggest that the different trends in surface temperature and mean ocean temperature during these intervals are related to a redistribution of heat between the surface and subsurface via changes in deep water formation and upwelling. Our temperature record also permits an estimate of global ice volume changes between 3 and 0.5million years ago through a deconvolution of the benthic foraminiferal δ18O record and points to a period of enhanced ice sheet growth around the time of the Mid-Pleistocene Transition.

DOI: 10.1038/s41586-026-10116-3

Source: https://www.nature.com/articles/s41586-026-10116-3