Iron supply pathways between the surface and subsurface waters of the Southern Ocean: From winter entrainment to summer storms
International audience Dissolved iron (DFe) plays an immeasurable role in shaping the biogeochemical processes of the open‐ocean Southern Ocean. However, due to observational constraints iron supply pathways remain poorly understood. Using an idealized eddy‐resolving physical‐biogeochemical model re...
Published in: | Geophysical Research Letters |
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Main Authors: | , , , , , |
Other Authors: | , , , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2019
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Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-02422875 https://hal.archives-ouvertes.fr/hal-02422875/document https://hal.archives-ouvertes.fr/hal-02422875/file/Nicholson_FINAL_GRL2019_R2_CLEAN_FIGURES.pdf https://doi.org/10.1029/2019GL084657 |
Summary: | International audience Dissolved iron (DFe) plays an immeasurable role in shaping the biogeochemical processes of the open‐ocean Southern Ocean. However, due to observational constraints iron supply pathways remain poorly understood. Using an idealized eddy‐resolving physical‐biogeochemical model representing a turbulent sector of the Southern Ocean with seasonal buoyancy forcing and zonal winds overlaid by storms, we quantify the importance of a range of subsurface and surface iron supply mechanisms. The main physical supply pathways to the surface layer are via eddy advection and winter convective mixing in equal proportions. The associated subsurface loss of DFe is restocked via net remineralization (75%) and eddy advection (25%). Summer storms resulted in weak DFe supplies relative to the seasonal supplies (<7.6%). However, in situations of deep summer mixed layers and when interacting with underlying ocean fronts, summer storms resulted in enhanced diffusive and advective DFe supplies and raised summer primary production by 20% for several days. |
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