Southern Ocean Upwelling and the Marine Iron Cycle
Thomas Weber
Abstract
Abstract The iron (Fe) supply to phytoplankton communities in the Southern Ocean surface exerts a strong control on oceanic carbon storage and global climate. Hydrothermal vents are one potential Fe source to this region, but it is not known whether hydrothermal Fe persists in seawater long enough to reach the surface before it is removed by particle scavenging. A new study (Jenkins, 2020, https://doi.org/10.1029/2020GL087266 ) fills an important gap in this puzzle: a helium‐3 mass balance model is used to show that it takes ~100 yr for deep hydrothermally influenced waters to upwell to the surface around Antarctica. However, estimates of Fe scavenging time scales range from tens to hundreds of years and must be more narrowly constrained to fully resolve the role of hydrothermal Fe in the ocean's biological pump.