澳大利亚塔斯马尼亚大学Weis Jakob研究小组报道，南大洋三分之一的生产力是由灰泥沉积支撑的。2024年5月15日出版的《自然》杂志发表了这项成果。

据悉，南大洋被风吹起的灰泥自然铁肥化可以提高生物生产力并调节气候。然而，这一过程从未在整个南大洋和年度尺度上被量化。

本研究将来自自主生物地球化学海洋剖面浮标的11年的硝酸盐观测数据与南半球灰泥模拟相结合，以实证推导出铁含量限制的南大洋灰泥-铁沉积与年净群落产量(ANCP)之间的关系。根据这一关系，研究人员确定了当前和末次盛冰期(LGM)南大洋远洋长期无冰区对灰泥铁离子的生物响应。

研究估计灰泥-铁现在支撑着南大洋ANCP33%±15%的海域。在LGM时期，当灰泥沉积比现在高5-40倍时，灰泥对南大洋ANCP的贡献要大得多，估计为64%±13%。研究结果提供了南大洋盆地范围内灰泥铁肥化的定量证据，及其对冰期-间冰期时间尺度的潜在影响程度，并支持了灰泥在全球碳循环和气候中发挥重要作用的观点。

附：英文原文

Title: One-third of Southern Ocean productivity is supported by dust deposition

Author: Weis, Jakob, Chase, Zanna, Schallenberg, Christina, Strutton, Peter G., Bowie, Andrew R., Fiddes, Sonya L.

Issue&Volume: 2024-05-15

Abstract: Natural iron fertilization of the Southern Ocean by windblown dust has been suggested to enhance biological productivity and modulate the climate. Yet, this process has never been quantified across the Southern Ocean and at annual timescales. Here we combined 11years of nitrate observations from autonomous biogeochemical ocean profiling floats with a Southern Hemisphere dust simulation to empirically derive the relationship between dust-iron deposition and annual net community production (ANCP) in the iron-limited Southern Ocean. Using this relationship, we determined the biological response to dust-iron in the pelagic perennially ice-free Southern Ocean at present and during the last glacial maximum (LGM). We estimate that dust-iron now supports 33%±15% of Southern Ocean ANCP. During the LGM, when dust deposition was 5–40-fold higher than today, the contribution of dust to Southern Ocean ANCP was much greater, estimated at 64%±13%. We provide quantitative evidence of basin-wide dust-iron fertilization of the Southern Ocean and the potential magnitude of its impact on glacial–interglacial timescales, supporting the idea of the important role of dust in the global carbon cycle and climate.

DOI: 10.1038/s41586-024-07366-4

Source: https://www.nature.com/articles/s41586-024-07366-4