Different Types of Freshwaters Have Different Impacts on Sea Surface pCO2 in the Arctic Ocean

Tozawa et al., (2024)


The Arctic Ocean uptake carbon dioxide (CO2) from the atmosphere strongly because of its low partial pressure of carbon dioxide (pCO2). Sea surface pCO2 varies due to temperature, freshwater, and biological activity. In addition, the Arctic Ocean is strongly affected by global warming. To predict the future impact of environmental changes on CO2 exchange, it is important to quantitatively assess the factors contributing to variations in sea surface pCO2. By investigating the carbonate chemistry in the sea ice meltwater to assess the freshwater effect, we found that low salinity sea ice has higher pCO2 despite of lower dissolved inorganic carbon (DIC) and total alkalinity (TA). It means that lower salinity meltwater, such as snow meltwater and multi-year ice meltwater, has smaller effect on reducing pCO2 than meltwater from younger sea ice. Therefore, changes in the inflow of each freshwater type must be estimated, and their impact on pCO2 must be assessed.

Reference: Tozawa, M., Nomura, D., Matsuura, M., et al. (2024). Quantitative assessment of factors contributing to variations in sea surface pCO2 in the pacific sector of the Arctic Ocean. J. Geophys. Res.: Oceans, 129, e2024JC021012. https://doi.org/10.1029/2024JC021012

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