|Calcium carbonate saturation states along the West Antarctic Peninsula
In: Antarctic Science. Cambridge University Press: Oxford. ISSN 0954-1020; e-ISSN 1365-2079, meer
alkalinity; aragonite; Circumpolar Deep Water; inorganic carbon system; meltwater
- Jones, E.M.
- Hoppema, M.
- Bakker, K., meer
- de Baar, H.J.W., meer
The waters along the West Antarctic Peninsula (WAP) have experienced warming and increased freshwater inputs from melting sea ice and glaciers in recent decades. Challenges exist in understanding the consequences of these changes on the inorganic carbon system in this ecologically important and highly productive ecosystem. Distributions of dissolved inorganic carbon (CT), total alkalinity (AT) and nutrients revealed key physical, biological and biogeochemical controls of the calcium carbonate saturation state (Ωaragonite) in different water masses across the WAP shelf during the summer. Biological productionin spring and summer dominated changes in surface water Ω aragonite (ΔΩaragonite up to +1.39; ~90%) relative to underlying Winter Water. Sea-ice and glacial meltwaterconstituted a minor source of AT that increased surface water Ω aragonite (ΔΩaragonite up to +0.07; ~13%). Remineralization of organic matter and an influx of carbon-rich brines led to cross-shelf decreases in Ωaragonite in Winter Water and Circumpolar Deep Water. A strong biological carbon pump over the shelf created Ωaragonite oversaturation in surface waters and suppression of Ωaragonite in subsurface waters. Undersaturation of aragonite occurred at < ~1000 m. Ongoing changes along the WAP will impact the biologically driven and meltwater-driven processes that influence the vulnerability of shelf waters to calcium carbonate undersaturation in the future.