Abstract:
Ocean acidification is predicted to occur first in polar oceans. We investigated the
saturation state of waters with respect to calcite (Wcal) and aragonite (Warg) in six sections
along an Arctic outflow pathway through the Canadian Arctic Archipelago (CAA) and into
the northwestern Atlantic using dissolved inorganic carbon and total alkalinity
measurements from 2003 to 2005. The study area, a key region connecting the Arctic and
the North Atlantic, includes Smith Sound, Barrow Strait, Baffin Bay, Davis Strait,
Hudson Strait, and the Labrador Sea. The average Warg in the Arctic outflow was 1.18 ± 0.17
in Barrow Strait and 1.31 ± 0.14 in Smith Sound, with areas where Warg < 1. The Arctic
outflow through the CAA has a high content of Pacific waters, which have a low
saturation state. These waters can be traced along the western Baffin Bay to Davis Strait.
South of Davis Strait, this outflow is modified by mixing with slope and offshore waters
of Atlantic origin and with the outflow from Hudson Strait. Despite the mixing, low
saturation state water can still be identified on the southern Labrador Shelf. The
aragonite saturation horizon is found at ∼150 m in Barrow Strait; at 200 m in Baffin
Bay, Davis Strait, and Hudson Strait; and at 2300 m in the Labrador Sea. This study
provides baseline data of the saturation states for the waters of the CAA and the
northwest Atlantic. It also illustrates the downstream evolution of low saturation state
Arctic outflow in the northwest Atlantic.
