Contrasting greenhouse gas dynamics along a coastal‐to‐oligotrophic ocean continuum

Abstract The oceans play the dual role of carbon sinks and greenhouse gases (GHGs) sources in global climate change, but there are still gaps in understanding the GHG fluxes and regulation mechanisms across ecosystem scales. We conducted five cruises across a coastal‐to‐oligotrophic ocean continuum to evaluate the distributions and air‐sea exchange of carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 ). The results show that GHGs exhibit significant positive fluxes in the coastal zone, with N 2 O and CH 4 (CO 2 equivalent) accounting for 30–50% of the total flux. In contrast, about 40% of the CO 2 uptake is offset in the pelagic ocean, suggesting a spatial gradient pattern of “coastal enhancement–pelagic compensation.” In addition, we identified critical drivers and causal pathways for temperature, oxygen and nutrients. The study shows that oceanic non‐CO 2 gases have significant positive climate effects, which highlights the importance of the multi‐gas synergistic framework in assessing regional climate feedback.