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| Titel |
Interdecadal changes in intensity of the oxygen minimum zone off Concepción, Chile (~ 36° S), over the last century |
| VerfasserIn |
B. Srain, S. Pantoja, J. Sepulveda, C. B. Lange, P. Muñoz, R. E. Summons, J. McKay, M. Salamanca |
| 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 ; 12, no. 20 ; Nr. 12, no. 20 (2015-10-22), S.6045-6058 |
| Datensatznummer |
250118136
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| Publikation (Nr.) |
 copernicus.org/bg-12-6045-2015.pdf |
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| Zusammenfassung |
| We reconstructed oxygenation changes in the upwelling ecosystem off
Concepción (36° S), Chile, using inorganic and organic
proxies in a sediment core covering the last ca. 110 years of sedimentation
in this area. Authigenic enrichments of Mo, U and Cd were observed between
ca. 1935 and 1971 CE, implying a prolonged period with predominantly more
reduced conditions in bottom waters and surface sediments. Significant
positive correlations between redox-sensitive metals, algal sterols,
biomarkers of micro-aerophilic and anaerobic microorganisms, and archaeal
glycerol dialkyl glycerol tetraethers point to a tight coupling among bottom
water O2 depletion and increased primary and export production. The
time interval with low O2 of ca. 35 years seems to follow low-frequency
interdecadal variation of the Pacific Decadal Oscillation, and it may have
resulted in O2 depletion over the entire continental shelf off
Concepción. Taking this together with the concurrent increase in sedimentary
molecular indicators of micro-aerophilic and anaerobic microbes, we can
suggest that changes in oxygenation of the water column are reflected by
changes in microbial community. This study can inform our understanding of
ecological consequences to projected trends in ocean deoxygenation. |
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