The Xingu River is a large clearwater tributary in the eastern Amazon with unique biodiversity and socioeconomic importance. Anthropogenic impacts such as deforestation and hydropower dams building can promote shifts in hydroclimate and sedimentation, affecting ecosystems and carbon cycling. Severe climatic changes are expected to affect the eastern Amazon during the next decades. However, the impacts and responses of these climatic anomalies remain unsettled. The reconstruction of Holocene hydroclimate in the Xingu basin is a critical issue to improve the reliability of climate change projections and their effects on Amazonian rivers. As such, we propose to study a sediment core collected at the Xingu River mouth under the influence of the Amazon River plume to constrain hydroclimate changes during the middle and late Holocene using organic geochemistry proxies. Soil and suspended sediment samples will be used to characterize signals of organic geochemistry proxies in the modern system. The hydrogen and stable carbon isotope ratios of plant lipids will be used as proxies for paleoprecipitation and paleoenvironmental conditions. Alkane abundances will indicate the relative contribution of modern and petrogenic sources to the sedimentary record. The comparison of organic and inorganic geochemistry proxies will elucidate the climatic controls affecting the hydrodynamic interaction between the Amazon and the Xingu rivers through the last 4,000 years. It will also provide a remarkable high resolution record for paleoenvironmental conditions in eastern Amazon. The internship will be developed at the MARUM - Center for Marine Environmental Sciences (Germany) under supervision of Dr. Enno Schefu². This proposal will enable the proponent to learn the analytical procedures of biomarkers and compound specific isotopes as well as to interpret the obtained data.
News published in Agência FAPESP Newsletter about the scholarship: