Hawco Nicholas J, Conway Tim M, Coesel Sacha N, Barone Benedetto, Seelen Emily A, Yang Shun-Chung, Bundy Randelle M, Pinedo-Gonzalez Paulina, Bian Xiaopeng, Sieber Matthias, Lanning Nathan T, Fitzsimmons Jessica N, Foreman Rhea K, König Daniela, Groussman Mora J, Allen James G, Juranek Lauren W, White Angelicque E, Karl David M, Armbrust E Virginia, John Seth G
Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI 96822.
College of Marine Science, University of South Florida, St. Petersburg, FL 33701.
Proc Natl Acad Sci U S A. 2025 Jun 10;122(23):e2418201122. doi: 10.1073/pnas.2418201122. Epub 2025 Jun 2.
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.
工业活动增加了海洋中铁的供应量，但人为输入的规模及其生态后果尚未得到观测数据的充分限制。在对北太平洋过渡区进行的四次考察中，我们记录到春季有来自大气源的同位素轻质铁的反复供应，这反映出人为因素对表层海洋铁预算的贡献估计为39±9%。宏转录组中缺铁应激基因的表达，以及铁和氮共同限制生态系统生产力的证据，表明铁供应增加应会刺激春季浮游植物大量繁殖，加速冬季混合作用带来的硝酸盐的季节性消耗。这种效应与卫星海洋颜色的区域趋势一致，即春季水华期更短、强度更大，随后夏季贫营养状况提前到来。持续的铁排放可能会导致过渡性海洋生态系统向极地转移，加剧海洋变暖和分层预期带来的影响。
