Sources of dFe and pFe and biogeochemical processes associated with the ‘meltwater pump’ vertical buoyancy-driven circulation in the Dotson Ice Shelf cavity are indicated, showing upper and lower mCDW layers and pathways (dark blue), ice shelf meltwater that includes both dFe from the ice melt itself and interactions with ice-entombed particles and glacial till (light blue), and discharge of subglacial meltwater (yellow). Dissolved and particulate Fe indicated with circles and squares, respectively. Also shown are entrainment and mixing of subglacial and ice shelf meltwaters with inflowing upper mCDW to form a buoyant plume, particulate Fe sources and settling, and relevant measurements of the concentration and isotopic composition of dissolved Fe. Note symbol density is not in strict proportion to relative dissolved and particulate Fe concentrations. Pie chart shows the calculated contribution of dFe from ice shelf meltwater, subglacial discharge, mCDW, and sedimentary sources, at the Dotson Ice Shelf outflow station.
[8/8] Cette étude montre que la fonte agit surtout comme une pompe physique. Elle favorise la remontée vers la surface d’un fer profond déjà enrichi. Comprendre la circulation océanique devient donc central pour anticiper l’évolution des écosystèmes antarctiques. #geography #ironcycle #SouthernOcean
