Droughts and climate-change-driven warming are leading to more frequent and intense wildfires^1,2,3, arguably contributing to the severe 2019–2020 Australian wildfires⁴. The environmental and ecological impacts of the fires include loss of habitats and the emission of substantial amounts of atmospheric aerosols^5,6,7. Aerosol emissions from wildfires can lead to the atmospheric transport of macronutrients and bio-essential trace metals such as nitrogen and iron, respectively^8,9,10. It has been suggested that the oceanic deposition of wildfire aerosols can relieve nutrient limitations and, consequently, enhance marine productivity^11,12, but direct observations are lacking. Here we use satellite and autonomous biogeochemical Argo float data to evaluate the effect of 2019–2020 Australian wildfire aerosol deposition on phytoplankton productivity. We find anomalously widespread phytoplankton blooms from December 2019 to March 2020 in the Southern Ocean downwind of Australia. Aerosol samples originating from the Australian wildfires contained a high iron content and atmospheric trajectories show that these aerosols were likely to be transported to the bloom regions, suggesting that the blooms resulted from the fertilization of the iron-limited waters of the Southern Ocean. Climate models project more frequent and severe wildfires in many regions^1,2,3. A greater appreciation of the links between wildfires, pyrogenic aerosols¹³, nutrient cycling and marine photosynthesis could improve our understanding of the contemporary and glacial–interglacial cycling of atmospheric CO₂ and the global climate system.

干旱和气候变化驱动的变暖正在导致更频繁和更强烈的野火^1,2,3，可以说是造成 2019-2020 年澳大利亚严重野火⁴的原因。火灾对环境和生态的影响包括栖息地的丧失和大量大气气溶胶的排放^5,6,7。野火产生的气溶胶排放可导致常量营养素和生物必需微量金属（如氮和铁）的大气运输，分别为^8,9,10。有人提出，野火气溶胶的海洋沉积可以缓解营养限制，从而提高海洋生产力^11,12，但缺乏直接观察。在这里，我们使用卫星和自主生物地球化学 Argo 浮标数据来评估 2019-2020 年澳大利亚野火气溶胶沉积对浮游植物生产力的影响。从 2019 年 12 月到 2020 年 3 月，我们在澳大利亚的南大洋顺风处发现了异常广泛的浮游植物水华。来自澳大利亚野火的气溶胶样本含有高铁含量，大气轨迹表明这些气溶胶很可能被运送到水华地区，这表明水华是由南大洋含铁量有限的水域施肥造成的。^{气候模型预测在许多地区1,2,3}会发生更频繁和更严重的野火。进一步了解野火与热源气溶胶之间的联系¹³，养分循环和海洋光合作用可以提高我们对大气CO ₂的当代和冰川-间冰期循环和全球气候系统的理解。