Halocline structure in the Canada Basin of the Arctic Ocean

Abstract

We examine the varieties and spatial distributions of Pacific and Eastern Arctic origin halocline waters in the Canada Basin using 2002–2003 hydrographic data. The halocline structure in the Canada Basin is different from the Eastern Arctic halocline because it includes fresher Pacific Winter Waters that form a “cold halostad” which lies above the Eastern Arctic origin lower halocline waters. The structure of the halostad in the Canada Basin, however, is not spatially uniform, and depends on the pathway and history of the source water. Pacific Winter Water entering through the Bering Strait becomes salty due to sea ice formation and this, in turn, is dependent on the occurrence and distribution of polynyas. In particular, saline water from the eastern Chukchi Sea forms thick halostad and causes depression of the isohalines in the southern Canada Basin. This depression influences thermohaline structure of the oceanic Beaufort Gyre.

Low <i>p</i>CO<sub>2</sub> under sea-ice melt in the Canada Basin of the western Arctic Ocean

“…In the western Arctic Ocean, the water at the temperature minimum layer (∼ 150 dbar) is known to originate in the North Pacific and be advected into the Arctic through the Bering Strait (POW: Pacific-origin water; Shimada et al, 2005), and the water in the layer above the temperature minimum is thought to be a mixture of this POW with sea-ice melt (SIM) and RRO. To determine the fractions (f ) of the three different source waters -POW, SIM, and RRO -in the upper-layer waters of the Chukchi Sea and the Canada Basin, we used the relationship between salinity and TA and the following mass balance equations.…”

Origin of freshwater and polynya water in the Arctic Ocean halocline in summer 2007

“…The strong vertical gradients in the Arctic Ocean halocline insulate the sea ice cover from the heat in the relatively warm Atlantic waters underneath (Björk and Söderkvist, 2002;Shimada et al, 2005). Below the surface mixed layer there is a strong and cold halocline, which is largely maintained by waters from the shelf seas (Aagaard et al, 1981) as well as convective offshore processes (Steele and Boyd, 1998).…”

Ocean currents shape the microbiome of Arctic marine sediments

“…Atlantic water enters the Arctic through the Fram Strait, and moves counter-clockwise along the ABS break. During summer, as ice melts and vertical mixing is reduced, water on the ABS is density stratified, resulting in a layer of Pacific origin water sandwiched between an Arctic surface layer, and a deep, cold and saline layer of Atlantic origin water (Carmack and Macdonald, 2002;McLaughlin et al, 2004;Shimada et al, 2005). The halocline (40-100 m) between surface and Pacific water and pycnocline (200 m) between Pacific and Atlantic water physically separates these masses (McLaughlin et al, 2004;Pickart, 2004).…”