Global modeling study of aerosol iron deposition into marine ecosystems in the Anthropocene

Abstract

Anthropogenic, pyrogenic, and lithogenic iron (Fe) aerosols affect marine ecosystems and climate through the food chain starting with phytoplankton (primary producers) by providing vital nutrient (Fe) to the ocean surface layer. However, there is a large uncertainty in the estimate of nutrient supply from those sources. Particularly in the Southern Ocean, underestimates of observed data on the mass concentration of bioaccessible Fe in aerosols have led to hypotheses such as missing sources in global models and underestimation of Fe dissolution rates (Ito et al., Science Advances, 2019). In this review paper, we summarize the progress in research on how bioaccessible Fe in aerosols affects marine biogeochemistry and ecosystems from atmosphere (emission, transformation, radiation, and deposition processes) to post-deposition (leaching into seawater as bioavailable Fe). Future perspectives include interdisciplinary research of field observational, laboratory experimental, and numerical modeling studies.