Microbial iron limitation in the ocean's twilight zone

• 成果类型: Article
• 署名作者: Li, Jingxuan; Babcock-Adams, Lydia; Boiteau, Rene M.; Mcilvin, Matthew R.; Manck, Lauren E.; Sieber, Matthias; Lanning, Nathan T.; Bundy, Randelle M.; Bian, Xiaopeng; Streanga, Iulia-Madalina; Granzow, Benjamin N.; Church, Matthew J.; Fitzsimmons, Jessica N.; John, Seth G.; Conway, Tim M.; Repeta, Daniel J.
• 署名单位: Woods Hole Oceanographic Institution; Massachusetts Institute of Technology (MIT); State University System of Florida; Florida State University; University of Minnesota System; University of Minnesota Twin Cities; University of Montana System; University of Montana; State University System of Florida; University of South Florida; Texas A&M University System; Texas A&M University College Station; University of Washington; University of Washington Seattle; University of Southern California; University of California System; University of California San Diego; Scripps Institution of Oceanography
• 刊物名称: Nature
• ISSN/ISSBN: 0028-4356
• DOI: 10.1038/s41586-024-07905-z
• 发表日期: 2024-09-26
• 关键词: amphiphilic siderophores; membrane affinity; trace-elements; marine; GROWTH; remineralization; pacific; ligands; complexation; metabolism

摘要

Primary production in the sunlit surface ocean is regulated by the supply of key nutrients, primarily nitrate, phosphate and iron (Fe), required by phytoplankton to fix carbon dioxide into biomass1-3. Below the surface ocean, remineralization of sinking organic matter rapidly regenerates nutrients, and microbial metabolism in the upper mesopelagic 'twilight zone' (200-500 m) is thought to be limited by the delivery of labile organic carbon4,5. However, few studies have examined the role of nutrients in shaping microbial production in the mesopelagic6-8. Here we report the distribution and uptake of siderophores, biomarkers for microbial Fe deficiency9 across a meridional section of the eastern Pacific Ocean. Siderophore concentrations are high not only in chronically Fe-limited surface waters but also in the twilight zone underlying the North and South Pacific subtropical gyres, two key ecosystems for the marine carbon cycle. Our findings suggest that bacterial Fe deficiency owing to low Fe availability is probably characteristic of the twilight zone in several large ocean basins, greatly expanding the region of the marine water column in which nutrients limit microbial metabolism, with potential implications for ocean carbon storage. The distribution and uptake of siderophores across a meridional section of the eastern Pacific Ocean suggests that iron availability limits microbial metabolism in the upper mesopelagic in several large ocean basins.