IBBEA   24401
INSTITUTO DE BIODIVERSIDAD Y BIOLOGIA EXPERIMENTAL Y APLICADA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Comparison of oxygen isotope records from lakes and tree-rings in southern Patagonia (OXICLIM)
Autor/es:
DUBOIS, NATHALIE; MAUAD, MELINA; SMITH, REBECCA; MAYR, C.; GARCÍA, MARÍA LUJÁN; RODRIGUEZ-CATÓN, MILAGROS; ZOLITSCHKA, B.; LÜCKE, ANDREAS; MASSAFERRO, J.; SRUR, ANA
Lugar:
Vienna
Reunión:
Congreso; European Geosciences Union General Assembly 2018; 2018
Resumen:
The recently launched Argentinean-German joint project ?Synthesis of oxygen isotope proxies for climate reconstructionin southern Patagonia? (OXICLIM) is a scientific initiative intended to combine regional continentalclimate archives by means of oxygen isotope records. The long-term aim of our study is to provide the foundationfor quantitative climate reconstructions using statistical methods and mechanistic models. The study area, close toLos Glaciares National Park in southern Patagonia, exhibits a distinct humidity gradient evident as a transition fromhumid Andean Nothofagus forest to Patagonian steppe. The ends of this gradient, humid and dry, are representedhere by Laguna Verde (49.20°S; 72.98°W) and Laguna Las Gemelas Este (49.39°S; 72.90°W), respectively. ForLaguna Verde we have found weak but significant negative correlations (r2=-0.28 and r2=-0.26) of tree-ring widthwith temperature variability and the Southern Annular Mode index, respectively. For both sites, we have extractedcellulose from multi-decadal tree-ring records from the lakes? catchments and analysed the 18O/16O ratios of singleyears. Concurrently, chironomid head capsules and aquatic cellulose were extracted from the lake sedimentsand their oxygen isotope ratios were analysed. Radiometric dating (210Pb, 137Cs) and tephrochronology provide arobust chronology of the last century for the sediment cores, whereas tree-rings are annually dated from presentdaybackwards. The oxygen isotope composition of tree-ring cellulose from Nothofagus pumilio reflects the sourcewater isotopic composition overprinted by plant physiology and air humidity changes. The lacustrine oxygen isotoperecords reflect the isotopic composition of lake water, which is determined by hydrological constraints suchas the lake water balance and the history of air masses controlled by orography and moisture sources. Combiningboth oxygen isotope archives tree-ring cellulose and lake sediment - is a novel and challenging approach. The bestway to test its applicability is possible in areas with a strong hydrological gradient, such as along the eastern flanksof the Patagonian Andes.