近日，法国布雷斯特大学Eva Bucciarelli团队报道了西印度亚南极浮游植物大量繁殖，受到富含铁的阿古拉斯水的滋养。这一研究成果于2025年10月27日发表在《自然—地球科学》杂志上。
在西印度亚南极区持续观察到跨越100万平方公里的浮游植物繁盛。这个位于南大洋印度板块的亚热带和亚南极锋面之间的海洋区域贡献了20-40%的南大洋向深海输出的碳。然而，作为初级生产的关键限制养分，风吹来的铁只支持了浮游植物对铁的一半需求。
研究组揭示了西印度亚南极地区的初级生产是通过阿古拉斯洋流（沿非洲南部海岸向西南流动的最强洋流之一）的铁的远程运输来维持的。漂浮物轨迹和高分辨率模型诊断表明，这些在非洲边缘富含铁的水域，通过该地区强烈的中尺度涡旋变率穿过亚热带锋。在模型中去除非洲沉积铁质会使西印度亚南极区表面铁浓度降低55%，使年初级产量和碳输出分别减少25%和26%。因此，在过去130年里，阿古拉斯回流的加强可能增加了印度亚南极区的铁供应和古生产力，可能导致大气中二氧化碳的减少。
附：英文原文
Title: Western Indian subantarctic phytoplankton blooms fertilized by iron-enriched Agulhas water
Author: Bucciarelli, Eva, Penven, Pierrick, Pous, Stphane, Tagliabue, Alessandro
Issue&Volume: 2025-10-27
Abstract: A phytoplankton bloom spanning 1 million km2 is consistently observed in the western Indian Subantarctic Zone. This oceanic region between the Subtropical and Subantarctic fronts in the Indian sector of the Southern Ocean contributes 20–40% of Southern Ocean carbon export to the deep ocean. However, aeolian inputs of iron, the key limiting nutrient for primary production, support only half of the phytoplanktonic iron demand of this bloom. Here we show that primary production in the western Indian Subantarctic Zone is sustained by long-range transport of iron via the Agulhas Current, one of the strongest ocean currents, which flows southwestward along the southern African coast. Float trajectories and high-resolution model diagnostics indicate that these waters, enriched with iron over the African margin, cross the Subtropical Front via the region’s intense mesoscale eddy variability. Removing the African sedimentary iron source in the model decreases surface iron concentrations in the western Indian Subantarctic Zone by 55%, reducing annual primary production and carbon export by 25% and 26%, respectively. Strengthening of the Agulhas Return Current over the past 130 kyr may therefore have increased iron supply and palaeoproductivity in the Indian Subantarctic Zone, potentially leading to enhanced atmospheric CO2 drawdown.
DOI: 10.1038/s41561-025-01823-z
Source: https://www.nature.com/articles/s41561-025-01823-z