biostudies-literatureUnknown10(37)Wang ZCoastal oceans, traditionally seen as a conduit for transporting atmospheric carbon dioxide (CO₂)-derived anthropogenic carbon (C_ANT) to open oceans, exhibit complex carbon exchanges at their interface. South China Sea (SCS) exemplifies this complexity, where interactions with the Pacific, particularly through Kuroshio intrusion, challenge the understanding of C_ANT source and variability in a coastal ocean. Contrary to prevailing paradigm expectations, our high-resolution, long-term data reveal that C_ANT in the SCS primarily originates from Pacific water injection across the Luzon Strait rather than atmospheric CO₂ invasion. Over the past two decades, the SCS has experienced increasing C_ANT levels, with notable interannual fluctuations driven by El Niño and La Niña events influencing Kuroshio intrusion, generating anomalously high and low C_ANT inventories, respectively. This highlights an overlooked C_ANT transport pathway from open to coastal oceans, responsible for cumulative ocean acidification that has already affected coral reefs enriched in the SCS located west of the Coral Triangle.Science advanceseadn9171https://www.ebi.ac.uk/biostudies/studies/S-EPMC11397484biostudies-literaturePacific Ocean-originated anthropogenic carbon and its long-term variations in the South China Sea.PMC11397484Roberts ELiu ZDai MCao ZZhai WGan JLuo YLin YWang ZfalsePacific Ocean-originated anthropogenic carbon and its long-term variations in the South China Sea.Coastal oceans, traditionally seen as a conduit for transporting atmospheric carbon dioxide (CO₂)-derived anthropogenic carbon (C_ANT) to open oceans, exhibit complex carbon exchanges at their interface. South China Sea (SCS) exemplifies this complexity, where interactions with the Pacific, particularly through Kuroshio intrusion, challenge the understanding of C_ANT source and variability in a coastal ocean. Contrary to prevailing paradigm expectations, our high-resolution, long-term data reveal that C_ANT in the SCS primarily originates from Pacific water injection across the Luzon Strait rather than atmospheric CO₂ invasion. Over the past two decades, the SCS has experienced increasing C_ANT levels, with notable interannual fluctuations driven by El Niño and La Niña events influencing Kuroshio intrusion, generating anomalously high and low C_ANT inventories, respectively. This highlights an overlooked C_ANT transport pathway from open to coastal oceans, responsible for cumulative ocean acidification that has already affected coral reefs enriched in the SCS located west of the Coral Triangle.2024-01-01T00:00:00Z2024 Sep2025-04-05T18:42:01.872Z2025-04-05T18:42:01.872ZS-EPMC113974843927002310.1126/sciadv.adn9171