Physical and chemical oceanography in the Arctic Ocean


Data from sections across the Eurasian Basin of the Arctic Ocean occupied by the German Research Vessel Polarstern in 1987 and by the Swedish icebreaker Oden in 1991 are used to derive information on the freshwater balance of the Arctic Ocean halocline and on the sources of the deep waters of the Nansen, Amundsen and Makarov basins.Salinity, d18O and mass balances allow separation of the river-runoff and the sea-ice meltwater fractions contained in the Arctic halocline. This provides the basis for tracking the river-runoff signal from the shelf seas across the central Arctic Ocean to Fram Strait. The halocline has to be divided into at least three lateral regimes: the southern Nansen Basin with net sea-ice melting, the northern Nansen Basin and Amundsen Basin with net sea-ice formation and increasing river-runoff fractions, and the Canadian Basin with minimum sea-ice meltwater and maximum river-runoff fractions and water of Pacific origin. In the Canadian Basin, silicate is used as a tracer to identify Pacific water entering through Bering Strait and an attempt is made to quantify its influence on the halocline waters of the Canadian Basin. For this purpose literature data from the CESAR and LOREX ice camps are used.Based on mass balances and depending on the value of precipitation over the area of the Arctic Ocean the average mean residence time of the river-runoff fraction contained in the Arctic Ocean halocline is determined to be about 14 or 11 years. Water column inventories of river-runoff and sea-ice meltwater are calculated for a section just north of Fram Strait and implications for the ice export rate through Fram Strait are discussed.Salinity, tritium, 3He and the d18O ratio of halocline waters sampled during the 1987 Polarstern cruise to the Nansen Basin are used to estimate the mean residence time of the river-runoff component in the halocline and on the shelves of the Arctic Ocean. These estimates are done by comparing ages of the halocline waters based on a combination of tracers yielding different time information: the tritium 'vintage' age which records the time that has passed since the river-runoff entered the shelf and the tritium/3He age which reflects the time since the shelf waters left the shelf. The difference between the ages determined by these two methods is about 3 to 6 years. Correction for the initial tritium/3He age of the shelf waters (about 0.5 to 1.5 years) yields a mean residence time of the river-runoff on the shelves of about 3.5 ± 2 years. Comparison of the 18O/16O ratios of shelf water, Atlantic water and the deep waters of the Arctic Ocean indicate that the sources of the deep and bottom waters of the Eurasian Basin are located in the Barents and Kara seas.

Supplement to: Bauch, Dorothea (1995): The distribution of d18O in the Arctic Ocean: implications for the freshwater balance of the halocline and the sources of deep and bottom waters (Die Verteilung von d18O im Arktischen Ozean: Implikationen für die Süßwasserbilanz der Halokline und die Quellen des Tiefen- und Bodenwassers). Berichte zur Polarforschung = Reports on Polar Research, 159, 144 pp

Related Identifier
Metadata Access
Creator Bauch, Dorothea ORCID logo
Publisher PANGAEA
Publication Year 1995
Funding Reference Fourth Framework Programme Crossref Funder ID MAS3970141 Silicon Cycling in the World Ocean; Fourth Framework Programme Crossref Funder ID MAS3980185 Quaternary Environment of the Eurasian North
Rights Creative Commons Attribution 3.0 Unported;
OpenAccess true
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 6 datasets
Discipline Earth System Research
Spatial Coverage (-17.520W, 70.000S, 163.603E, 88.277N); off Novaya Zemlya; Nordenskiöld Bay; Wilczek Island; off Franz-Josef-Land; Chejsa Island; Green Bell Island; Greenland Sea; Arctic Ocean; North Greenland Sea
Temporal Coverage Begin 1987-06-10T18:41:00Z
Temporal Coverage End 1992-01-01T00:00:00Z