Alkalinity of sea ice in the high-latitudinal arctic according to the surveys performed at north pole drifting station 34 and characterization of the role of the arctic ice in the CO2 exchange

摘要

The variability of the total alkalinity in the sea ice of the high-latitudinal Arctic from November 2005 to May 2006 is considered. For the bulk of the one- and two-year sea ice, the alkalinity dependence on the salinity is described as TA = k × Sal, where k is the salinity: alkalinity ratio in the under-ice water. The given relationship is valid within a wide salinity range from 0.1 psu in the desalinated fraction of two-year ice to 36 psu in the snow on the young ice surface. Geochemically significant deviations from the relationship noted were observed exclusively in the snow and the upper layer of one-year ice. In the upper layer of one-year ice, an alkalinity deficiency is observed (ΔTA -0.07 mequiv/kg, or -15%). In the snow on the surface of the one-year ice, an alkalinity excess is formed under the desalination (ΔTA is as high as 1.3 mequiv/kg, 380%). The deviations registered are caused by the possibility of carbonate precipitation in the form of CaCO3 · 6H2O under the seawater freezing. It is shown that the ice formation and the following melting might cause a loss of the atmospheric CO2 of up to 3 × 1012 g C/year. (PUBLICATION ABSTRACT)