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| Titel |
Coupled CO2 and O2-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System |
| VerfasserIn |
E. Mayol, S. Ruíz-Halpern, C. M. Duarte, J. C. Castilla, J. L. Pelegrí |
| 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. 3 ; Nr. 9, no. 3 (2012-03-28), S.1183-1194 |
| Datensatznummer |
250006853
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| Publikation (Nr.) |
 copernicus.org/bg-9-1183-2012.pdf |
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| Zusammenfassung |
| Carbon dioxide and coupled CO2 and O2-driven compromises to marine
life were examined along the Chilean sector of the Humboldt Current System,
a particularly vulnerable hypoxic and upwelling area, applying the
Respiration index (RI = log10 pO2pCO2) and the
pH-dependent aragonite saturation (Ω) to delineate the water masses
where aerobic and calcifying organisms are stressed. As expected, there was
a strong negative relationship between oxygen concentration and pH or
pCO2 in the studied area, with the subsurface hypoxic Equatorial
Subsurface Waters extending from 100 m to about 300 m depth and supporting
elevated pCO2 values. The lowest RI values, associated to aerobic
stress, were found at about 200 m depth and decreased towards the Equator.
Increased pCO2 in the hypoxic water layer reduced the RI values by as
much as 0.59 RI units, with the thickness of the upper water layer that
presents conditions suitable for aerobic life (RI>0.7) declining by half
between 42° S and 28° S. The intermediate waters hardly reached those
stations closer to the equator so that the increased pCO2 lowered pH and
the saturation of aragonite. A significant fraction of the water column
along the Chilean sector of the Humboldt Current System suffers from
CO2–driven compromises to biota, including waters corrosive to
calcifying organisms, stress to aerobic organisms or both. The habitat free
of CO2-driven stresses was restricted to the upper mixed layer and to
small water parcels at about 1000 m depth. Overall pCO2 acts as a hinge
connecting respiratory and calcification challenges expected to increase in
the future, resulting in a spread of the challenges to aerobic organisms. |
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