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

ABSTRACT: 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 s

SUBMITTER: Hawco NJ 

PROVIDER: S-EPMC12168011 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature