Reconstructing Past Climates of the Amazon Basin from the Isotopic Analysis of Tropical Trees

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The primary goal of this research is to reconstruct Amazon climate, primarily precipitation at annual resolution, for the past few centuries by constructing tree-ring width chronologies and analyzing the carbon and oxygen isotopic composition of cellulose from tropical trees that are known to produce annual rings. The research will be conducted, primarily, in the Amazon Basin and includes a Peruvian Andes altitudinal transect, Peruvian lowlands site, and two Brazilian lowlands sites.Previous research has shown that tree-ring width indices and oxygen isotope ratios are correlative with precipitation and that carbon isotopic ratios are related to water-use efficiency and precipitation. Further calibration of the isotopic and ring-width proxies, however, is needed. Likewise the ring-width chronology will be tested at each site by analyzing Carbon-14 in tree cellulose and comparing these values with the known Southern hemisphere atmospheric Carbon-14 signal. Broad goals of the research include a better understanding of climate variability from the geochemical examination of tropical tree rings, support of a post-doctoral scholar, and close international collaboration with colleagues in South America.