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Titel |
Spectrophotometric Measurements of the Carbonate Ion Concentration: Aragonite Saturation States in the Mediterranean Sea and Atlantic Ocean |
VerfasserIn |
Maribel I. Garcia-Ibañez, Noelia M. Fajar, Henar SanLeón-Bartolomé, Marta Álvarez, Fiz F. Perez |
Konferenz |
EGU General Assembly 2016
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 18 (2016) |
Datensatznummer |
250121386
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Publikation (Nr.) |
EGU/EGU2016-81.pdf |
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Zusammenfassung |
Measurements of ocean pH, alkalinity, and carbonate ion concentrations ([CO32−]) during
three cruises in the Atlantic Ocean and one in the Mediterranean Sea were used to assess the
reliability of the recent spectrophotometric [CO32−] methodology and to determine
aragonite saturation states. Measurements of [CO32−] along the Atlantic Ocean showed
high consistency with the [CO32−] values calculated from pH and alkalinity, with
negligible biases (0.4 ± 3.4 μmol⋅kg−1). In the warm, salty, high alkalinity and high pH
Mediterranean waters, the spectrophotometric [CO32−] methodology underestimates the
measured [CO32−] (4.0 ± 5.0 μmol⋅kg−1), with anomalies positively correlated to
salinity. These waters also exhibited high in situ [CO32−] compared to the expected
aragonite saturation. Their very high buffering capacity allows the Mediterranean Sea
waters to remain over the saturation level of aragonite for long periods of time.
Conversely, the relatively thick layer of undersaturated waters between 500 and 1000
m depths in the Tropical Atlantic is expected to progress to even more negative
undersaturation values. Moreover, the northern North Atlantic presents [CO32−]
slightly above the level of aragonite saturation, and the expected anthropogenic
acidification could result in reductions of the aragonite saturation levels during future
decades, acting as a stressor for the large population of cold-water-coral communities. |
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