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| Titel |
Observed acidification trends in North Atlantic water masses |
| VerfasserIn |
M. Vázquez-Rodríguez, F. F. Pérez, A. Velo, A. F. Ríos, H. Mercier |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 12 ; Nr. 9, no. 12 (2012-12-18), S.5217-5230 |
| Datensatznummer |
250007466
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| Publikation (Nr.) |
 copernicus.org/bg-9-5217-2012.pdf |
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| Zusammenfassung |
| The lack of observational pH data has made it difficult to assess recent rates
of ocean acidification, particularly in the high latitudes. Here we present
a time series that spans over 27 yr (1981–2008) of high-quality carbon
system measurements in the North Atlantic, which comprises fourteen cruises
and covers the important water mass formation areas of the Irminger and
Iceland Basins. We provide direct quantification of acidification rates in
upper and intermediate North Atlantic waters. The highest rates were
associated with surface waters and with Labrador Sea Water (LSW). The
Subarctic Intermediate and Subpolar Mode Waters (SAIW and SPMW) showed
acidification rates of −0.0019 ± 0.0001 and −0.0012 ± 0.0002 yr−1,
respectively. The deep convection activity in the North Atlantic
Subpolar Gyre injects surface waters loaded with anthropogenic CO2 into
lower layers, provoking the remarkable acidification rate observed for LSW
in the Iceland Basin (−0.0016 ± 0.0002 yr−1). An extrapolation of
the observed linear acidification trends suggests that the pH of LSW could
drop 0.45 units with respect to pre-industrial levels by the time
atmospheric CO2 concentrations reach ~775 ppm. Under circulation
conditions and evolution of CO2 emission rates similar to those of the
last three decades, by the time atmospheric CO2 reaches 550 ppm, an
aragonite undersaturation state could be reached in the cLSW of the Iceland
Basin, earlier than surface SPMW. |
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