The seasonal cycle of δ13CDIC in the North Atlantic subpolar gyre

This study introduces for the first time the δ13CDIC seasonality in the North Atlantic subpolar gyre (NASPG) using δ13CDIC data obtained in 2005-2006 and 2010-2012 with dissolved inorganic carbon (DIC) and nutrient observations. On the seasonal scale, the NASPG is characterized by higher δ13CDIC val...

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Bibliographic Details
Published in:Biogeosciences 2014-03, Vol.11, p.1683-1692
Main Authors: Racapé, Virginie, Metzl, Nicolas, Pierre, Catherine, Reverdin, Gilles, Quay, P. D., Ólafsdóttir, Sólveig R.
Format: Article
Language:English
Subjects:
Earth Sciences
Environmental Sciences
Geophysics
Global Changes
Physics
Sciences of the Universe
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Summary:This study introduces for the first time the δ13CDIC seasonality in the North Atlantic subpolar gyre (NASPG) using δ13CDIC data obtained in 2005-2006 and 2010-2012 with dissolved inorganic carbon (DIC) and nutrient observations. On the seasonal scale, the NASPG is characterized by higher δ13CDIC values during summer than during winter, with a seasonal amplitude between 0.70 ± 0.10‰ (August 2010-March 2011) and 0.77 ± 0.07‰ (2005-2006). This is mainly attributed to photosynthetic activity in summer and to a deep remineralization process during winter convection, sometimes influenced by ocean dynamics and carbonate pumps. There is also a strong and negative linear relationship between δ13CDIC and DIC during all seasons. Winter data also showed a large decrease in δ13CDIC associated with an increase in DIC between 2006 and 2011-2012, but the observed time rates (-0.04‰ yr-1and +1.7 μmol kg-1 yr-1) are much larger than the expected anthropogenic signal.
ISSN:1726-4170
1726-4189
DOI:10.5194/BG-11-1683-2014