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

• 成果类型: Article
• 署名作者: Weis, Jakob; Chase, Zanna; Schallenberg, Christina; Strutton, Peter G.; Bowie, Andrew R.; Fiddes, Sonya L.
• 署名单位: University of Tasmania; University of Tasmania; University of Tasmania; University of Tasmania; Commonwealth Scientific & Industrial Research Organisation (CSIRO); CSIRO Environment
• 刊物名称: Nature
• ISSN/ISSBN: 0028-6390
• DOI: 10.1038/s41586-024-07366-4
• 发表日期: 2024-05-16
• 页码: 603-+
• 关键词: iron-fertilization experiment; dissolved iron; atlantic sector; mineral dust; nutrient; MODEL; biogeochemistry; variability; nitrate; fluxes

摘要

Natural iron fertilization of the Southern Ocean by windblown dust has been suggested to enhance biological productivity and modulate the climate(1-3). Yet, this process has never been quantified across the Southern Ocean and at annual timescales(4,5). 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(6-8).