近日，加拿大地质调查局（大西洋）Alexandre Normandeau团队研究了沿海海洋的冬季：季节性冻结导致海底膨胀和收缩。2025年10月31日，《科学-进展》杂志发表了这一成果。

极地地区的海底测绘已经使人们认识到与海底永久冻土有关的地貌。尽管最近的研究表明海底永久冻土正在迅速退化，但关于海底季节性变化的信息仍然有限。

研究组使用延时多波束测深（2021-2024）和底水温数据，揭示地表沉积物中作为冰形式的小冰泡（5米宽，20 - 50厘米高）的季节性形成和退化。这些冰泡于2021年10月在深度≤25米处消退，但在2023年7月广泛存在。它们在2023年7月至11月之间融化，在接下来的冬天重新形成，并在2024年8月再次出现。来自系泊底水传感器和沉积物岩心的数据表明，冰泡的形成和退化受深度季节性温度变化的驱动，并受到表层沉积物中新鲜孔隙水的影响。这项研究记录了以前未被认识到的由新鲜孔隙水的冻融循环驱动的海底季节性扩张和收缩。

附：英文原文

Title: Winter in the coastal ocean: Seasonal freezing causes seafloor expansion and contraction

Author: Alexandre Normandeau, Barret L. Kurylyk, Emma J. Harrison, Haley D. Geizer, Genevieve Philibert, Robert Way, Christopher L. Algar, Zachary MacMillan-Kenny, Jennifer L. Eamer, Nicolas Van Nieuwenhove, Jordan B. R. Eamer, Liz Pijogge, Frédéric Cyr, Ian Church, Eric Oliver, Michelle Saunders, Audrey Limoges

Issue&Volume: 2025-10-31

Abstract: Seafloor mapping in polar regions has led to the recognition of landforms associated with subsea permafrost. Despite recent studies indicating rapid subsea permafrost degradation, information on seasonal seafloor changes remains limited. Here, we use time-lapse multibeam bathymetry (2021–2024) and bottom-water temperature data to reveal seasonal formation and degradation of small frost blisters (5 meters wide and 20 to 50 centimeters high) as ice forms within surficial sediments. These frost blisters were degraded in October 2021 at depths of ≤25 meters but were widespread in July 2023. They thawed between July and November 2023, reformed over the following winter, and were present again in August 2024. Data from moored bottom-water sensors and sediment cores indicate that the formation and degradation of frost blisters are driven by seasonal temperature changes at depth and influenced by freshened porewater in surficial sediments. This study documents previously unrecognized seasonal expansion and contraction of the seafloor driven by freeze-thaw cycles of freshened porewater.

DOI: adw7439

Source: https://www.science.org/doi/10.1126/sciadv.adw7439