Biogeochemical Shifts During Arctic Spring: Potential Reduction of CH4 and N2O Emissions Driven by Surfactants in the Sea-surface Microlayer

Methane (CH₄) and nitrous oxide (N₂O) are potent greenhouse gases whose marine emissions offset a significant part of the global ocean CO₂ uptake. Yet, the magnitude, temporal-spatial variability and underlying mechanisms driving their exchange across the sea-air interface still constitute some of the largest uncertainties in marine greenhouse gas emissions. Such uncertainties are especially evident in polar ecosystems, in which the difficulty of access is a major constraint. Writing in The Cryosphere, Holthusen and colleagues present the first assessment on the role of the sea surface microlayer (SML) as a physical/chemical interface that could significantly reduce CH₄ and N₂O emissions from the Arctic. Through targeted sampling of undisturbed leads and under-ice water during the onset of sea ice melt and an early algal bloom in the Fram Strait (Arctic Ocean), the authors revealed that the region acted as a minor source of CH₄ and N₂O, potentially in connection with the accumulation of algal-derived surfactants in the SML. Their findings highlight the importance of resolving short-term surface processes during seasonal transitions and of integrating SML dynamics into investigating trace gas fluxes in polar regions.

Reference: Holthusen, L.A., Bange, H.W., Badewien, T.H., et al. (2026). Biogeochemical shifts during Arctic spring: potential reduction of CH4 and N2O emissions driven by surfactants in the sea-surface microlayer. The Cryosphere, 20, 535–550. https://doi.org/10.5194/tc-20-535-2026