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- Title
Sensitivity of ocean biogeochemistry to the iron supply from the Antarctic ice sheet explored with a biogeochemical model.
- Authors
Person, Renaud; Aumont, Olivier; Madec, Gurvan; Vancoppenolle, Martin; Laurent Bopp; Merino, Nacho
- Abstract
Iron (Fe) delivery by the Antarctic Ice Sheet (AIS) through ice shelf and iceberg melting enhances primary productivity in the largely iron-limited Southern Ocean (SO). To explore this fertilization capacity, we implemented a simple representation of the AIS iron source in the global ocean biogeochemical model NEMO-PISCES. We evaluated the response of Fe, surface chlorophyll, primary production and carbon export to the magnitude and hypothesized vertical distributions of the AIS Fe fluxes. Surface Fe and chlorophyll concentrations are increased up to 25% and 12%, respectively, over the whole SO. The AIS Fe delivery is found to have a relatively modest impact on SO primary production and C export which are increased by 0.063±0.036PgCyr-1 and 0.028±0.016PgCyr-1, respectively. However, in highly fertilized areas, primary production and C export can be increased by up to 30% and 42%, respectively. Icebergs are predicted to have a much larger impact on Fe, surface chlorophyll and primary productivity than ice shelves in the SO. The response of surface Fe and chlorophyll is maximum in the Atlantic sector, northeast of the tip of the Antarctic Peninsula, and along the East Antarctic coast. The iceberg Fe delivery below the mixed layer may, depending on its assumed vertical distribution, fuel a non-negligible subsurface reservoir of Fe. The Fe supply is effective all year round and seasonal variations in iceberg melting have regional impacts which are almost negligible for annual-mean primary productivity and C export at the scale of the SO.
- Subjects
ANTARCTIC ice; ICE sheets; BIOGEOCHEMISTRY; ICE shelves; OCEAN; MIXING height (Atmospheric chemistry)
- Publication
Biogeosciences Discussions, 2019, p1
- ISSN
1810-6277
- Publication type
Article
- DOI
10.5194/bg-2019-134