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Data obtained during the last 20 years from selected hydrographic stations throughout the Arctic Ocean basins and at the continental slopes and northern parts of the surrounding shelf seas are examined to estimate the contribution of Atlantic water to the upper part of the Arctic Ocean water column, and to follow the circulation of the Atlantic derived halocline waters around the Arctic Ocean basins. A substantial fraction of the Atlantic water entering the Arctic Ocean in the two inflow branches, the Fram Strait branch and the Barents Sea branch, is transformed into less dense waters. The inflow through Fram Strait encounters and melts sea ice. Its upper part becomes less saline, and in winter, ice formation homogenizes this low salinity upper part into a winter mixed layer, which follows the boundary flow eastward. The inflow over the Barents Sea mainly becomes colder, less saline and denser due to cooling and net precipitation, but melting of sea ice also here creates a less dense upper layer, which is subsequently homogenized by haline convection. Both these components enter the Nansen Basin via the St. Anna Trough and flow eastward along the Siberian continental slope. A third component of the Barents Sea inflow, mainly comprising Norwegian Coastal Current water, remains on the shelf, where it absorbs the runoff from the large Siberian rivers and evolves into low salinity shelf water. This part continues as far east as the Laptev Sea before a major inflow to the deep Arctic Ocean basins occurs. Winter convection, which in most of the Nansen Basin extends to the Atlantic layer, then becomes limited to the injected low salinity shelf water, and the more saline upper layers of the Fram Strait and the Barents Sea branches are transformed into halocline waters. The Fram Strait branch supplies the halocline water of the Amundsen, Makarov and part of the Canada basins, while the upper part of the Barents Sea branch, initially confined to the Siberian continental slope, becomes the main source of the lower halocline below the Pacific water in the Canada Basin beyond the Chukchi Cap. Less dense Pacific water close to the North American continent prevents the Atlantic derived upper layers from fl owing through the Canadian Arctic Archipelago and their main exit is Fram Strait. Only some of the Barents Sea branch halocline water passes through Nares Strait and may occasionally renew the deep and bottom waters of Baffin Bay. [ABSTRACT FROM AUTHOR]

It has been predicted that the Arctic Ocean will sequester much greater amounts of carbon dioxide (CO2) from the atmosphere as a result of sea ice melt and increasing primary productivity. However, this prediction was made on the basis of observations from either highly productive ocean margins or ice-covered basins before the recent major ice retreat. We report here a high-resolution survey of sea-surface CO2 concentration across the Canada Basin, showing a great increase relative to earlier observations. Rapid CO2 invasion from the atmosphere and low biological CO2 drawdown are the main ' causes for the higher CO2, which also acts as a barrier to further CO2 invasion. Contrary to the current view, we predict that the Arctic Ocean basin will not become a large atmospheric CO2 sink under ice-free conditions. [ABSTRACT FROM AUTHOR]

Abstract: From August 2002 to September 2004 a high-resolution mooring array was maintained across the western Arctic boundary current in the Beaufort Sea north of Alaska. The array consisted of profiling instrumentation, providing a timeseries of vertical sections of the current. Here we present the first-year velocity measurements, with emphasis on the Pacific water component of the current. The mean flow is characterized as a bottom-intensified jet of O (15cms−1) directed to the east, trapped to the shelfbreak near 100m depth. Its width scale is only 10–15km. Seasonally the flow has distinct configurations. During summer it becomes surface-intensified as it advects buoyant Alaskan Coastal water. In fall and winter the current often reverses (flows westward) under upwelling-favorable winds. Between the storms, as the eastward flow re-establishes, the current develops a deep extension to depths exceeding 700m. In spring the bottom-trapped flow advects winter-transformed Pacific water emanating from the Chukchi Sea. The year-long mean volume transport of Pacific water is 0.13±0.08Sv to the east, which is less than 20% of the long-term mean Bering Strait inflow. This implies that most of the Pacific water entering the Arctic goes elsewhere, contrary to expected dynamics and previous modeling results. Possible reasons for this are discussed. The mean Atlantic water transport (to 800m depth) is 0.047±0.026Sv, also smaller than anticipated. [Copyright &y& Elsevier]

Provides information on a study conducted to determine the factors which contributes to changes in temperature and tracer properties in the Arctic Ocean. Factors which contributes to changes in the salinity of North Atlantic waters; Methodology used; Mechanisms involved in thermohaline transitions which appeared in Nansen, Amunsden and Makarov basins; Other findings obtained in the study.