近日，德国奥尔登堡卡尔·冯·奥西茨基大学Torben Struve团队揭示了南太平洋碳吸收受南极西部冰盖动力学控制。2026年2月2日出版的《自然—地球科学》杂志发表了这项成果。

微量营养元素铁的供应增加会促进缺铁的南大洋输出生产力的提升，从而形成动态的大气二氧化碳汇，这一机制放大了过去的气候变化。通常认为该机制主要受控于风尘输送铁的总量及其溶解度。

研究组通过沉积学与地球化学示踪手段，研究了南大洋南极带最大区域（太平洋扇区）的铁输入与碳吸收过程。数据显示，过去50万年间，西南极冰盖动态的千年尺度变化同时控制了该区域颗粒铁的供应量与陆源颗粒组成（影响颗粒溶解度）。研究表明，相比于总铁输入量，化学性质更原始的冰川海洋颗粒（高溶解度）的丰度提升对提供生物可利用铁、增强输出生产力具有关键作用。

高陆源铁通量往往对应化学性质成熟的颗粒（低溶解度），这尤其出现在西南极冰盖显著消融期。相应的输出生产力在此期间处于低值，表明这种“冰盖-铁反馈”机制在冰盖退缩阶段呈正反馈效应——即冰盖退缩导致铁溶解性降低，反而削弱了海洋固碳能力。因此，未来西南极冰盖的退缩很可能降低南大洋太平洋扇区这一广阔海域的碳吸收能力。

附：英文原文

Title: South Pacific carbon uptake controlled by West Antarctic Ice Sheet dynamics

Author: Struve, Torben, Lamy, Frank, Gng, Frederik, Klages, Johann P., Kuhn, Gerhard, Esper, Oliver, Lembke-Jene, Lester, Winckler, Gisela

Issue&Volume: 2026-02-02

Abstract: Increased supply of the micronutrient iron promotes export production in the iron-limited Southern Ocean, thus acting as a dynamic sink of atmospheric CO2 that has amplified past climate variations. This mechanism is typically considered to be regulated by the amount and solubility of iron delivered by aeolian transport. Here we use sedimentological and geochemical tracers to investigate iron input and carbon uptake in the largest sector of the Southern Ocean Antarctic Zone. Our data show that millennial-scale variations in West Antarctic Ice Sheet dynamics controlled both the supply of particulate iron and lithogenic particle composition (affecting particle solubility) in the Pacific Antarctic Zone over the last 500,000 years. Rather than the total iron input, a higher abundance of chemically more pristine glaciomarine particles (high particle solubility) was critical for providing bioavailable iron, which enhanced export production. High lithogenic iron fluxes are characterized by chemically mature particles (low particle solubility), in particular during phases of pronounced ice loss in West Antarctica. The corresponding export production was low, indicating that this ‘ice-sheet–iron feedback’ is positive during these retreat phases. Accordingly, future West Antarctic Ice Sheet retreat is likely to decrease carbon uptake in the large Pacific sector of the Southern Ocean.

DOI: 10.1038/s41561-025-01911-0

Source: https://www.nature.com/articles/s41561-025-01911-0