Concentrations and controls of dissolved inorganic carbon in Arctic summer sea ice and adjacent surface seawaters

• Published in: Marine environmental research Vol. 190; p. 106083
• Main Authors: Cai, Xiaoxia, Zhuang, Yanpei, Wu, Yingxu, Lin, Hongmei, Qi, Di
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2023
• Subjects: Arctic Ocean; Arctic region; carbon; Carbon cycle; carbonates; climate; DIC; dissolved inorganic carbon; Ice melt; oceans; sea ice; Sea-ice carbon pump; summer; surface water; Arctic Ocean; Arctic region; Carbon cycle; Sea-ice carbon pump; Arctic Ocean; Ice melt; DIC
• ISSN: 0141-1136; 1879-0291; 1879-0291
• DOI: 10.1016/j.marenvres.2023.106083

The carbonate chemistry of sea ice plays a critical role in global ocean carbon cycles, particularly in polar regions which are subject to significant climate change-induced sea ice variation. However, less is known about the interaction of carbonate system between sea ice and its adjacent seawaters due to sparse sampling and disparities in reported results. Here we provide an insight into this issue by collecting and measuring dissolved inorganic carbon (DIC) and associated environmental parameters in Arctic sea ice during a cruise in the summer of 2014. Our observations show that DIC in Arctic summer sea ice has a mean concentration of 463.3 ± 213.0 μmol/kg and appears to be controlled mainly by the fraction of brine water in the ice. The low Chl a and nutrients content in sea ice indicate minor contribution of biological uptake to sea-ice DIC in the western Arctic Ocean. The DIC concentration in surface water (<100 m depth) decreased from a mean of 2108.3 ± 45.4 μmol/kg in 1994 to a mean of 2052.4 ± 98.6 μmol/kg in 2014, due to the enhanced sea ice melting that dilutes the DIC concentrations of surrounding seawaters. •Sea-ice DIC has a mean concentration of 463.3 ± 213.0 μmol/kg during a summer cruise in the western Arctic Ocean.•Sea-ice DIC is controlled mainly by the fraction of brine water in sea ice rather than biological uptake.•The meltwater input might have caused the observed decrease in DIC concentration in surface water between 1994 and 2014.