近日，瑞典斯德哥尔摩大学Hong, W.-L.团队揭示了冰川消融推动海水入渗，减缓海底地下水排放。相关论文于2025年8月6日发表在《自然—地球科学》杂志上。

海底地下水排放-地下水流入海洋-在形成沿海生物地球化学循环中起着重要作用。近端冰川负荷驱动的近海地下水动力学缺乏时间限制，妨碍了人们评估其环流在可想象的无冰极地如何变化。

研究组估计了咸水在挪威北部沿海大陆架断裂附近一个活跃的海底地下水排放和甲烷渗漏点的停留时间。由于芬诺斯坎德冰盖的动态变化，该地区的地下水文经历了剧烈的变化，这为了解冰川-间冰期转变对近海地下水的影响提供了见解。通过对上行平流地下水中溶解无机碳的放射性碳定年，研究组在两个不同的发射地点确定了咸水的停留时间为11.5 ~ 8.8凯尔和4.8~2.6凯尔。

沉积物孔隙水中大气水成分的存在证实了由过去冰川负荷驱动的近海地下水更新。这表明，随着冰盖的消退和海平面的上升，海水开始渗入地下，取代淡水补给。该结果提供了观测证据，精确地指出了在边缘消冰后海水入渗的开始。这些发现表明，冰川的退缩将深刻地改变近海地下水的组成并降低排放速率。

附：英文原文

Title: Deglaciation drove seawater infiltration and slowed submarine groundwater discharge

Author: ten Hietbrink, S., Patton, H., Dugan, B., Szymczycha, B., Sen, A., Lepland, A., Knies, J., Kim, J.-H., Chen, N.-C., Hong, W.-L.

Issue&Volume: 2025-08-06

Abstract: Submarine groundwater discharge—the flow of groundwater into the ocean—plays an important role in shaping coastal biogeochemical cycles. The absence of temporal constraints on offshore groundwater dynamics driven by proximal glacial loading hinders our assessment of how its circulation may vary in conceivable ice-free polar regions. Here we estimate residence times of saline groundwater at an active submarine groundwater discharge and methane seep site off the coast of northern Norway, near the continental shelf break. The subsurface hydrology in this area experienced drastic changes due to Fennoscandian Ice Sheet dynamics, offering insights into the consequences of glacial–interglacial transitions for offshore groundwater. Using radiocarbon dating of dissolved inorganic carbon in the upwards-advected groundwater, we determined saline groundwater residence times of 11.5 to 8.8kyr and 4.8 to 2.6kyr at two distinct discharge sites. The presence of a meteoric water component in sediment porewaters confirms offshore groundwater freshening driven by past glacial loading. This indicates that, as the ice sheet retreated and sea levels rose, seawater began to infiltrate the subsurface, replacing freshwater recharge. Our results provide observational evidence pinpointing the onset of seawater infiltration following deglaciation of the margin. These findings suggest that retreating marine-terminating glaciers will profoundly alter offshore groundwater composition and reduce discharge rates.

DOI: 10.1038/s41561-025-01750-z

Source: https://www.nature.com/articles/s41561-025-01750-z