High Lability Fe Particles Sourced From Glacial Erosion Can Meet Previously Unaccounted Biological Demand: Heard Island, Southern Ocean

A significant source of bioavailable iron (Fe) in the Southern Ocean, previously unaccounted for, has been identified through glacial erosion on Heard Island. The study found that suspended particles from glacial erosion and fluvial outflow near Heard Island contain a high fraction of labile Fe (18 ± 2.8% of total Fe), sufficient to meet phytoplankton demand in the region. Researchers surveyed 11 stations around Heard and McDonald Islands, comparing particulate Fe lability using chemical leaching techniques. Unlike McDonald Island, where refractory minerals dominate, Heard Island's unique geological signature enhances Fe supply. This discovery underscores the critical role of glacial erosion in supporting the productivity of this historically highly productive region, with potential implications for future ecosystem shifts under climate change.

van der Merwe, P., Wuttig, K., Holmes, T., Trull, T. W., Chase, Z., Townsend, A. T., Goemann, K., & Bowie, A. R. (2019). High Lability Fe Particles Sourced From Glacial Erosion Can Meet Previously Unaccounted Biological Demand: Heard Island, Southern Ocean. Frontiers in Marine Science, 6. https://doi.org/10.3389/fmars.2019.00332