Seasonal Variation of CO2 air-sea flux and Effects of Warming in the Kuroshio Current of the East China Sea

Shou-En Tsao, Po-Yen Shen, Chun-Mao Tseng^*

The partial pressure of CO₂ (pCO₂) and CO₂ air-sea flux exhibit marked spatial and temporal variability across ocean margins, reflecting the complex interplay of regional environmental processes. Understanding these variations is fundamental to comprehending the global carbon cycle and predicting how oceans may respond to climate change.

A recent study published in Marine Chemistry documented seasonal CO₂ flux dynamics within the Kuroshio Current of the East China Sea (ECS), particularly in the context of warming oceans. The research reveals that the Kuroshio functions as a net CO₂ sink, with an annual uptake of approximately 1.3 mol C m⁻² yr⁻¹—less than the ECS shelf’s higher rate of ~1.8 mol C m⁻² yr⁻¹. Seasonal fluxes are thermally driven, making the Kuroshio a strong CO₂ sink in winter and transitioning to a weak source or net-neutral state in summer, contrasting with the biologically and physically driven fluxes of the ECS shelf. This highlights the contrasting controls on carbon dynamics within marginal seas, with tropical and subtropical regions, like the Kuroshio, being particularly vulnerable to the effects of climate warming.

Looking forward, ongoing warming trends could disrupt the seasonal balance of CO₂ fluxes, leading to shifts in interannual carbon dynamics. and impacting carbon storage potential and removal feasibilitiess in marginal seas. Long-term monitoring of dynamic systems like the Kuroshio Current is essential to understanding their evolving role in the global carbon cycle under climate change.

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S.-E. Tsao, P.-Y. Shen, C.-M. Tseng* (2024) Seasonal variation of CO₂ air-sea flux and effects of warming in the Kuroshio Current of the East China Sea, Marine Chemistry, 267, 104469, https://doi.org/10.1016/j.marchem.2024.104469.

A conceptual comparison of seasonal mean pCO₂, CO fluxes, and their controlling mechanisms between (a) the East China Sea (ECS) shelf and (b) the Kuroshio.