Abstract Hydrogen (H 2 ) influences the climate by prolonging the lifetime of greenhouse gases via consuming hydroxyl radicals. Despite the ocean's crucial role in regulating atmospheric H 2 , its marine biogeochemical cycle is poorly constrained. To bridge this gap, our research in the Western Tropical Pacific Ocean (WTPO) revealed a north–south increasing gradient in the surface (1.40–23.4 nmol L −1 ). Key processes encompassing photo‐production (1.43–4.36 nmol L −1 h −1 ), microbial consumption (0.57–1.92 nmol L −1 h −1 ), and sea‐to‐air exchange (1.19–11.3 × 10 −3 nmol L −1 h −1 ) were conducted to refine the budget estimation for the mixed layer. The highest photo‐production and consumption rates occurred at equatorial stations driven by La Niña–induced upwelling that supplied nutrients and organic matter. The sea–air flux in the WTPO was large enough to influence the turnover of atmospheric H 2 above the ocean. This research provides critical constraints for assessing oceanic H 2 emission and environmental impact.
Jiang et al. (Mon,) studied this question.