Interception of atmospheric fluxes by Arctic sea ice: Evidence from cosmogenic super(7)Be

• Published in: Journal of geophysical research. Oceans Vol. 116; no. C12
• Main Authors: Camara-Mor, P, Masque, P, Garcia-Orellana, J, Kern, S, Cochran, J K, Hanfland, C
• Format: Journal Article
• Language: English
• Published: 01-12-2011
• Subjects: Marine
• ISSN: 2169-9275; 2169-9291
• DOI: 10.1029/2010JC006847

The natural cosmogenic radionuclide super(7)Be (T sub(1/2) = 53.4 d) is supplied to the surface ocean from the atmosphere and, in the Arctic Ocean, can be used as a tracer of the efficiency with which sea ice intercepts the atmospheric fluxes of chemical species and of the importance of ice as a transport mechanism for particulate matter and chemical species. Analyses of super(7)Be in samples of surface water, surface sea ice, water beneath the ice, sea ice sediments, and precipitation from the Eurasian Basin of the Arctic Ocean show that the fraction of sea ice coverage determines the amount of super(7)Be in the surface water. When sea ice coverage is <40%, the super(7)Be inventory in the upper ocean (130 plus or minus 19 Bq m super(-2)) is in good agreement with that expected from the inventory from super(7)Be atmospheric flux (128 plus or minus 21 Bq m super(-2)). In contrast, when ice coverage is >80%, the water column inventory drops to 58 plus or minus 20 Bq m super(-2). The super(7)Be inventory in sea ice is 39 plus or minus 23 Bq m super(-2), and mass balance calculations show that sea ice can intercept 30 plus or minus 18% of the atmospheric flux of super(7)Be during the studied period. We suggest that other atmospherically transported contaminants should be similarly intercepted. super(7)Be in the ice also can be used to estimate that the annual transport and release of sediment to the ablation area of the Fram Strait is 500 g m super(-2), a value comparable to previously measured fluxes in sediment traps deployed in the area. Key Points * Sea ice intercepts 7Be atmospheric fluxes efficiently * Sea ice coverage determines the amount of 7Be in the surface water * 7Be is a useful tracer to study atmosphere-sea ice-ocean interaction