Glacial and Hydrothermal Sources of Dissolved Iron (II) in Southern Ocean Waters Surrounding Heard and McDonald Islands

Heard and McDonald Islands (HIMI) serve as significant sources of dissolved iron (II) (DFe(II)) in the Southern Ocean, with distinct mechanisms governing its release. Heard Island's glacial runoff contributes reduced iron, while McDonald Islands' shallow hydrothermal activity is a notable source. The study, conducted during the austral summer of 2016, used DFe(II) and hydrogen peroxide measurements to identify these sources. Elevated DFe(II) concentrations around HIMI, reaching up to 1.01 nmol L⁻¹ near McDonald Islands, suggest increased iron availability for marine biota and potential transport to the broader Kerguelen Plateau, where annual plankton blooms occur.

Holmes, T. M., Wuttig, K., Chase, Z., Schallenberg, C., van der Merwe, P., Townsend, A. T., & Bowie, A. R. (2020). Glacial and Hydrothermal Sources of Dissolved Iron (II) in Southern Ocean Waters Surrounding Heard and McDonald Islands. Journal of Geophysical Research: Oceans, 125(10). Portico. https://doi.org/10.1029/2020jc016286