Environmental context. Iron is an essential component of many enzyme systems of marine plants (phytoplankton), but in large areas of the global ocean iron is in such short supply as to hinder phytoplankton growth. This is of major environmental interest because phytoplankton growth can remove carbon from the atmosphere. This contribution seeks to improve the understanding of how dust transported through, and processed within, the atmosphere helps to supply usable iron to the plants of the remote ocean.

Abstract. Soil dust mobilised from arid regions is transported through and processed within the atmosphere before deposition to marine and terrestrial ecosystems remote from the source regions. This process represents a significant source of iron to the oceans, which creates feedback loops throughout the Earth’s system. The very limited solubility of iron from dust makes the determination of this solubility, how it varies and how this may influence ocean biogeochemistry of considerable importance. In this short communication we summarise a series of recent studies of mechanisms that control solubility and then consider how these results influence the inputs of iron to the oceans and their isotopic signature.