Anthropogenic iron alters the spring phytoplankton bloom in the North Pacific transition zone

• 成果类型: Article
• 署名作者: Hawco, Nicholas J.; Conway, Tim M.; Coesel, Sacha N.; Barone, Benedetto; Seelen, Emily A.; Yang, Shun - Chung; Bundy, Randelle M.; Gonzalez, Paulina; Bian, Xiaopeng; Sieber, Matthias; Lanning, Nathan T.; Fitzsimmons, Jessica N.; Foreman, Rhea K.; Konig, Daniela; Groussman, Mora J.; Allen, James G.; Juranek, Lauren W.; White, Angelicque E.; Karl, David M.; Armbrust, E. Virginia; John, Seth G.
• 署名单位: University of Hawaii System; University of Hawaii Manoa; State University System of Florida; University of South Florida; University of Washington; University of Washington Seattle; University of Southern California; University of Alaska System; University of Alaska Fairbanks; Oregon State University; Texas A&M University System; Texas A&M University College Station; Massachusetts Institute of Technology (MIT); Morgan State University; National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8468
• DOI: 10.1073/pnas.2418201122
• 发表日期: 2025-06-10
• 关键词: isotope ratios; co-limitation; aerosol iron; time-series; ocean; nutrient; fe; responses; climate; surface

摘要

Industrial activities have increased the supply of iron to the ocean, but the magnitude of anthropogenic input and its ecological consequences are not well-constrained by observations. Across four expeditions to the North Pacific transition zone, we document a repeated supply of isotopically light iron from an atmospheric source in spring, reflecting an estimated 39 +/- 9 % anthropogenic contribution to the surface ocean iron budget. Expression of iron-stress genes in metatranscriptomes, and evidence for colimitation of ecosystem productivity by iron and nitrogen, indicates that enhanced iron supply should spur spring phytoplankton blooms, accelerating the seasonal drawdown of nitrate delivered by winter mixing. This effect is consistent with regional trends in satellite ocean color, which show a shorter, more intense spring bloom period, followed by an earlier arrival of oligotrophic conditions in summer. Continued iron emissions may contribute to poleward shifts in transitional marine ecosystems, compounding the anticipated impacts from ocean warming and stratification.