Sea ice supplies carbon equal to 14.7% of ice-edge phytoplankton production

Sea ice in the Southern Ocean delivers a substantial share of the organic carbon that supports Antarctic marine ecosystems, according to a study published in Biogeosciences. A research team led by Keigo D. Takahashi collected sea ice samples and examined the factors controlling the amounts of particulate organic carbon and nitrogen they contain, together with the stable isotope ratios of those materials.

The analysis showed that nutrients and organic matter influence the isotope compositions recorded in sea ice. By combining hydrographic measurements with sea-ice data, the team estimated how much particulate organic carbon the ice supplies to surrounding waters.

The estimate is notable: the carbon supplied from sea ice was equivalent to 14.7 percent of phytoplankton production near the ice edge. That figure points to sea-ice derived material as a meaningful contributor to the base of the Antarctic food web, complementing open-water plankton growth.

Because the findings rest on field collections and isotope measurements from the Southern Ocean, they provide a quantitative basis for assessing the role of sea-ice derived materials in Antarctic ecosystems. The study highlights the importance of ice-associated organic matter for carbon cycling in polar waters.

Subject of Research: Biogeochemical controls on particulate organic matter in Southern Ocean sea ice and its carbon supply to Antarctic ecosystems

Article Title: Biogeochemical controls on the concentrations and stable isotope compositions of sea-ice particulate organic matters in the Southern Ocean

Article References: Takahashi, K. D., Makabe, R., Sano, M., Nakata, K., Kimura, N., Nomura, D., Yamamoto-Kawai, M., Matsuda, R., Nojiro, N., Ito, M., Takao, S., Horimoto-Miyazaki, N., Tachibana, A., Kurosawa, N., Tamura, T., Komatsu, M., Ohshima, K. I., Mizobata, K., Aoki, S., & Moteki, M. (2026). Biogeochemical controls on the concentrations and stable isotope compositions of sea-ice particulate organic matters in the Southern Ocean. Biogeosciences, 23(20), 7505-7522. https://doi.org/10.5194/bg-23-7505-2026

Image Credits: AI Generated

DOI: 10.5194/bg-23-7505-2026

Keywords: Southern Ocean, sea ice, particulate organic carbon, stable isotopes, phytoplankton production, Antarctic ecosystems, biogeochemistry, ice edge, carbon cycling, nutrients, Biogeochemical, controls