The El Niño Southern Oscillation is the major source of global interannual climate variability. However, little is known about the long-term variability of this phenomenon.
Oceanography and climate along the coast of Peru are fundamentally linked to ENSO variability.
Between the El Niño events, extensive upwelling of cool and nutrient-rich water makes the Peruvian continental shelf one of the most bioproductive marine systems. Organic matter decay causes strong oxygen minimum conditions between 50 and 650 m water depths, favouring the preservation of laminated diatomaceous and diatom bearing oozes.
During El Niño events, upwelling of nutrient rich water (and therefore bioproduction) is subdued and extensive rainfall reaches into some regions of otherwise (hyper-) arid coastal deserts. Precipitation run-off erodes fine-grained lithics from soils. These are flushed via rivers into the sea where they are dispersed over hundreds of kilometres along the continental shelf by the Peru Current. Sedimentary archives on the outer continental shelf thus can integrate the discharge of riverine lithic suspension from a great number of river catchments along the Peruvian coast.
Sediment cores with laminated marine sediments were recovered on the continental shelf and slope off Peru between 9°S and 14°S during cruise SO-147 with the German Research Vessel Sonne.
Slide show: Works during Cruise SO-147 [avi , 4.7 MB]
We use the fine-grained lithic fraction and the photosynthetic pigments in the sediments and sea surface temperature reconstructions from alkenones as proxies for paleo El Niño activity.
In-situ reflectance spectroscopy techniques developed during this project revealed proxy data from these cores which resolve interannual variability during the last two interglacial periods and Terminations since 130,000 years ago. Glacial periods are resolved with decadal to multi-decadal resolution.
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Rein, B., A. Lückge, R. Lutz, F. Sirocko, A Wolf, C-W. Dullo (2005): El Niño varia-bility off Peru during the last 20,000 years. Paleoceanography, 20, PA4003 (1-17), doi:10.1029/2004PA001099. [ PDF]
Rein, B., Lückge & F. Sirocko (2004): A major Holocene ENSO anomaly during the Medieval period. Geophysical Research Letters, 31: L17211, doi:10.1029/2004GL020161. [ PDF incl. aux. mat.]
Rein, B. (rev. ms subm.): How do the 1982/83 and 1997/98 El Niños rank in a geological record from Peru? Quaternary International. [ PDF]
Rein, B., F. Sirocko, A. Lückge, L. Reinhardt, A. Wolf, C-W. Dullo (revised ms subm.): Abrupt change of El Niño activity during the last interglacial. In Frank Sirocko, Thomas Litt, Martin Claussen, F. Sanchez-Goni (eds.): The climate of the past interglacials. [ PDF]
Downloads
106KL data for the last 20 kyrs:
Lithics – lithic concentrations and flux rates (Excel-File).
Suggested citation:
- concentrations 0-12 kyrs cal BP (Rein et al., 2004)
- concentrations 12-20 kyrs cal BP (Rein et al., 2005)
- flux rates (0-20 kyrs cal BP (Rein et al., 2005)
Chlorins – chlorin concentrations and flux rates (Excel-File)
Suggested citation:
- (Rein et al., 2005)
Carotenoids – carotenoid concentrations and flux rates (Excel-File).
Suggested citation:
- (Rein et al., 2005)
Sea surface temperatures reconstructed from alkenones (Excel-File).
Suggested citation:
- (Rein et al., 2005)
Other high resolution techniques for the acquisition of paleoclimate proxy data from sediments (multispectral digital image analysis of laminated sediments).