近日，北京大学王学军团队揭示了气候变暖极大地放大了南极海岸冰融，使其成为关键的碳汇。该项研究成果发表在2025年12月8日出版的《美国科学院院刊》杂志上。
南大洋通过吸收大气二氧化碳在全球碳循环中扮演重要角色，助力减缓气候变化。南极沿海冰间湖是关键的二氧化碳吸收区，但关于这些二氧化碳是否能以有机碳形式有效封存于海洋沉积物，以及该过程的时空动态和驱动机制尚不明确。研究组结合现有数据与实地测量，重建了从全新世（约距今12000年以来）至今冰间湖沉积物中有机碳累积通量与来源的高分辨率记录。结果发现，尽管南极沿海冰间湖仅占南大洋面积的3%，却贡献了南大洋现代有机碳总累积量的约42%。自全新世以来，在气候变暖驱动下，有机碳累积量增长了九倍，其主要贡献来自海洋初级生产力的提升。
结构方程模型显示：气候变暖通过扩大和延长冰间湖的开阔水域面积，增强了生物碳泵效率与有机碳累积效率，且面积更大的冰间湖表现出更强的反馈效应。此外，冰架底部融化释放的细颗粒物质进一步促进了有机碳累积。该研究结果揭示，气候变暖已显著增强了南极沿海冰间湖的碳封存效率，使其成为南大洋中快速扩张的关键碳汇，未来可能对气候变化产生重要的负反馈调节作用。
附：英文原文
Title: Warming substantially amplifies Antarctic coastal polynyas as key carbon sinks
Author: Zhou, Chengzhen, Liu, Maodian, Rosenheim, Brad E., Bianchi, Thomas S., Zhang, Nikki H., Cai, Xingrui, Zhang, Qianru, Wang, Xuejun
Issue&Volume: 2025-12-8
Abstract: The Southern Ocean plays an important role in the global carbon cycle by absorbing atmospheric CO2, aiding climate change mitigation. Antarctic coastal polynyas (ACPs) are key CO2 uptake areas, yet whether this CO2 is effectively sequestered as organic carbon (OC) in marine sediments, and the spatiotemporal dynamics and drivers of this process, remains unclear. Here, we reconstruct a high-resolution record of Holocene (~12,000 y BP) to present-day OC accumulation fluxes and sources in ACP sediments using existing data as well as our measurements. We find that despite covering only 3% of the Southern Ocean, ACPs account for approximately 42% of the modern OC accumulation across the Southern Ocean. Since the Holocene, OC accumulation has increased ninefold due to climate warming, largely driven by marine primary production. Structural equation modeling reveals that warming enhances the biological carbon pump and OC accumulation efficiency by expanding and prolonging open water areas in ACPs, with larger ACPs showing stronger feedback. Furthermore, basal melt from ice shelves releases fine particulate matter, further boosting OC accumulation. Our findings highlight that climate warming has greatly amplified ACPs’ carbon-sequestration efficiency, making them rapidly expanding and crucial carbon sinks in the Southern Ocean, with the potential to provide strong negative feedback in future climate change.
DOI: 10.1073/pnas.2511585122
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2511585122