Trends of anthropogenic CO2 along 20º W in the Iberian Basin

Nm Fajar,M Vázquez-Rodríguez,L Carracedo,Af Ríos,Pc Pardo,Ff Pérez

doi:10.7773/cm.v38i1b.1810

Nm Fajar, M Vázquez-Rodríguez + Show 4 more

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https://doi.org/10.7773/cm.v38i1b.1810

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Journal: Ciencias Marinas	Publication Date: Oct 24, 2011
Citations: 7	License type: cc-by

Affiliation: Instituto de Investigacións Mariñas

Abstract

The carbon system in the water masses of the Iberian Basin (North Atlantic Ocean) has been affected over the last two decades by the increase in anthropogenic CO2 (Cant). In order to study the storage of Cant in the Iberian Basin, variables of the carbonic system (i.e., pH, total inorganic carbon, and total alkalinity), among others, were measured during the CAIBOX cruise conducted between July and August 2009 within the framework of the CAIBEX project (Shelf-Ocean Exchanges in the Canary-Iberian Large Marine Ecosystem). The storage of Cant was estimated using two different back-calculation techniques (i.e., the φCºT and TrOCA methods) and for six layers of the water column corresponding to the approximate locations of the characteristic water masses of the region and the mixed layers. For the whole water column and for the year 2009 the Cant storage values determined by the φCºT and TrOCA methods were 88.1 ± 3.8 and 93.7 ± 3.7 molC m–2, respectively. Moreover, the Cant storage rate from 1993 to 2009 was also estimated considering data from three additional cruises (OACES 1993, CHAOS 1998, and OACES 2003). The Cant storage rates were 1.41 ± 0.25 and 1.67 ± 0.13 molC m–2 yr–1 with the φCºT and TrOCA methods, respectively. An increase in anthropogenic CO2 uptake by the ocean can be seen when compared with previous published results. Between the periods 1977–1997 and 1993–2009, the Cant concentration increased around 28–49% in the first 2000 m.

Highlights

Since the 18th century, the beginning of the industrial period, humankind has emitted large quantities of CO2 into the atmosphere (Le Quéré 2009), the global average atmospheric CO2 rising from 280 ppm at the start of the industrial revolution to 381 ppm in 2006 (Canadell et al 2007)
The concentration of CO2 antropogénico (Cant) was estimated by the φCT0 and TrOCA methods for each of the cruises previously described (OACES 1993, CHAOS 1998, OACES 2003) and section 20o W from CAIBOX 2009, and the distributions of the variables obtained with each method are shown in figure 3
The range of variation depends on the cruise and slightly on the method, and gradually increases from 0–50 μmol kg–1 in OACES 1993 to 0–70 μmol kg–1 in CAIBOX 2009

Summary

Introduction

Since the 18th century, the beginning of the industrial period, humankind has emitted large quantities of CO2 into the atmosphere (Le Quéré 2009), the global average atmospheric CO2 rising from 280 ppm at the start of the industrial revolution to 381 ppm in 2006 (Canadell et al 2007). Los resultados de los modelos actuales limitan las tasas medias de captación de CO2 de la tierra y el océano para el periodo 1990–2000 a 2.6 ± 0.7 y 2.2 ± 0.4 Pg C año−1, Ciencias Marinas, Vol 38, No 1B, 2012 models estimated that the CO2 uptake rates were 2.7 ± 1.0 and 2.3 ± 0.5 Pg C yr−1 for land and ocean, respectively (Le Quéré et al 2009). These results show the variability of these CO2 sinks and the decreasing trend in the ocean CO2 uptake fraction. As the world’s oceanic reservoir accounts for approximately 90% of the natural carbon (Sabine and Tanhua 2010), better knowledge of the variability in the rate of uptake and size of the ocean CO2 sink is needed to predict global climate effects

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