The seasonal cycle of δ3CDIC in the North Atlantic subpolar gyre

Autor: V. Racapé, N. Metzl, C. Pierre, G. Reverdin, P. D. Quay, S. R. Olafsdottir
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: Biogeosciences, Vol 11, Iss 6, Pp 1683-1692 (2014)
Druh dokumentu: article
ISSN: 1726-4170
1726-4189
DOI: 10.5194/bg-11-1683-2014
Popis: 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.
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