Evaluation of anthropogenic carbon in the Nordic Seas using observed relationships of N, P and C versus CFCs

Citation:
Jutterstrom, S, Jeansson E, Anderson LG, Bellerby R, Jones EP, Smethie WM, Swift JH.  2008.  Evaluation of anthropogenic carbon in the Nordic Seas using observed relationships of N, P and C versus CFCs. Progress in Oceanography. 78:78-84.

Date Published:

Jul

Keywords:

anthropogenic carbon, calibration, CFCs, co2, dioxide, east greenland current, greenland sea, Iceland Sea, nordic seas, north-atlantic ocean, norwegian sea, nutrient relationships, seawater, water mass ages

Abstract:

Several methods to compute the anthropogenic component of total dissolved inorganic carbon (C-T(anthro)) the ocean have been reported, all in some way deducing (a) the effect by the natural processes, and (b) the background concentration in the pre-industrial scenario. In this work we present a method of calculating C-T(anthro) using nutrient and CFC data, which takes advantage of the linear relationships found between nitrate (N), phosphate (P) and CFC-11 in the Nordic Seas sub-surface waters. The basis of the method is that older water has lower CFC-11 concentration and also has been exposed to more sinking organic matter that has decayed, resulting in the slopes of P versus CFC-11 and N versus CFC-11 being close to the classic Redfield ratio of 1:16. Combining this with the slope in total alkalinity (A(T)) versus CFC-11 to correct for the dissolution of metal carbonates gives us the possibility to deduce the concentration of anthropogenic C-T in the Nordic Seas. This further allowed us to compute the inventory of anthropogenic C-T below 250 m in the Nordic Seas in spring 2002, to similar to 1.2 Gt C. (C) 2008 Elsevier Ltd. All rights reserved.

Notes:

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Website

DOI:

10.1016/j.pocean.2007.06.001