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| Titel |
Calcium carbonate saturation in the surface water of the Arctic Ocean: undersaturation in freshwater influenced shelves |
| VerfasserIn |
M. Chierici, A. Fransson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 11 ; Nr. 6, no. 11 (2009-11-04), S.2421-2431 |
| Datensatznummer |
250004083
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| Publikation (Nr.) |
 copernicus.org/bg-6-2421-2009.pdf |
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| Zusammenfassung |
| In the summer of 2005, we sampled surface water and measured pH and total
alkalinity (AT) underway aboard IB Oden along the Northwest Passage from Cape
Farewell (South Greenland) to the Chukchi Sea. We investigated the
variability of carbonate system parameters, focusing particularly on
carbonate concentration [CO32−] and calcium carbonate
saturation states, as related to freshwater addition, biological processes
and physical upwelling. Measurements on AT, pH at 15°C, salinity
(S) and sea surface temperature (SST), were used to calculate total
dissolved inorganic carbon (CT), [CO32−] and the
saturation of aragonite (ΩAr) and calcite (ΩCa) in the
surface water. The same parameters were measured in the water column of the
Bering Strait. Some surface waters in the Canadian Arctic Archipelago (CAA)
and on the Mackenzie shelf (MS) were found to be undersaturated with respect
to aragonite (ΩAr<1). In these areas, surface water was low in
AT and CT (<1500 μmol kg−1) relative to seawater and
showed low [CO32−]. The low saturation states were probably due to
the likely the effect of dilution due to freshwater addition by sea ice melt
(CAA) and river runoff (MS). High AT and CT and low pH,
corresponded with the lowest [CO32−], ΩAr and ΩCa,
observed near Cape Bathurst and along the South Chukchi Peninsula. This was
linked to the physical upwelling of subsurface water with elevated CO2.
The highest surface ΩAr and ΩCa of 3.0 and 4.5,
respectively, were found on the Chukchi Sea shelf and in the cold water
north of Wrangel Island, which is heavily influenced by high CO2
drawdown and lower CT from intense biological production. In the
western Bering Strait, the cold and saline Anadyr Current carries water that
is enriched in AT and CT from enhanced organic matter
remineralization, resulting in the lowest ΩAr (~1.2) of the
area. |
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