Health & Environmental Research Online (HERO)


Print Feedback Export to File
3243113 
Journal Article 
Calcium carbonate saturation in the surface water of the Arctic Ocean: undersaturation in freshwater influenced shelves 
Chierici, M; Fransson, A 
2009 
Yes 
Biogeosciences
ISSN: 1726-4170
EISSN: 1726-4189 
6 
11 
2421-2431 
WOS:000272232200006 
In the summer of 2005, we sampled surface water and
measured pH and total alkalinity (A(T)) 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 A(T), pH at 15 degrees C, salinity (S) and sea surface temperature
(SST), were used to calculate total dissolved inorganic carbon (C-T), [CO32-] and the saturation
of aragonite (Omega Ar) and calcite (Omega Ca) 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 (Omega Ar<1). In these areas, surface water was low in AT and CT (<1500 mu mol 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 A(T) and C-T and low pH, corresponded with the lowest [CO32-], Omega Ar and Omega Ca,
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 Omega Ar and Omega
Ca 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 C-T from intense
biological production. In the western Bering Strait, the cold and saline Anadyr Current carries
water that is enriched in A(T) and C-T from enhanced organic matter remineralization, resulting
in the lowest Omega Ar (similar to 1.2) of the area.