RV Investigator Voyage Summary: HEOBI – Heard Earth-Ocean-Biosphere Interactions

Iron supply limits oceanic primary production in the Southern Ocean as well as elsewhere in the global ocean. We aim to test the hypothesis that hydrothermal activity driven by active submarine magmatism fertilises surface waters with iron, thereby enhancing biological productivity. Heard and McDonald islands on the Kerguelen Plateau are among the world’s most active hotspot volcanoes, and are type examples sourced from a particular geochemical component in the Earth’s mantle (enriched mantle 1, or EM1). Existing data indicate that fields of submarine volcanoes extend for several hundred kilometres away from the islands.