Freshwater budget of the Canada Basin, Arctic Ocean, from salinity, δ18O, and nutrients

The contribution of freshwater components ( e. g., meteoric, sea ice, and Pacific water) in the Canada Basin is quantified using salinity, delta O-18, and nutrient data collected in 2003 and 2004. The penetration depth of sea ice meltwater is limited to the upper 30 m, and brine, rejected during sea ice formation, is observed from 30 to 250 m depth. The fraction of meteoric water is high in the upper 50 m and decreases with depth. Pacific water entering via Bering Strait is the main source of freshwater below 50 m depth. Bering Strait throughflow, which transports Pacific water with salinity 32.5 together with meteoric water supplied upstream of the Bering Strait, contributes up to 75% of freshwater input (>3200 km(3) a(-1)) to the Canada Basin. The mean residence time of Pacific water in the Canada Basin is estimated to be 11 years. Precipitation and river runoff from both North American and Eurasian continents add >800 km(3) a(-1) and sea ice formation removes <900 km(3) a(-1) (< 0.6 m a(-1)) of fresh water. The export of ice and liquid fresh water from the Canada Basin contributes similar to 40% of the freshwater flux from the Arctic Ocean to the North Atlantic Ocean.