Astrid Contreras Rosales

PhD project:

Changes in hydrology and land cover in three large river catchments of southern Asia during the Holocene recorded in marine archives

This PhD project is developed within the frame of a large cooperation project funded by the BMBF entitled “Natural versus anthropogenic controls of past monsoon variability in Central Asia recorded in marine archives (CARIMA)”. The specific objectives of my PhD project are (1) to assess the influence that changes on land cover and the hydrological cycle, within three large-river drainage basins, had on the composition and quantity of the transported terrestrial organic matter to the ocean, and (2) to identify the possible effects that human-induced changes on land-cover had on the precipitation patterns in the studied areas. For these purposes three sediment cores from the South China Sea (MD05-2905), the Bay of Bengal (SO188-342KL) and the Arabian Sea (SO130-289KL) will be analyzed. These sediment cores are located in the neighborhood of the Pearl River, Ganges-Brahmaputra and Indus River deltas respectively. Sediment samples from the cores will be analyzed for bulk parameters (C[total], N[total], C[org], δ13C[org], δ15N), amino acids composition, plant-derived n-alkanes composition, and compound-specific stable isotopes (δ13C, δD) in n-alkanes. These biochemical proxies will be used for the reconstruction of terrestrial organic matter deposition and degradation state in marine sediments, and the relations between vegetation and precipitation patterns in the drainage basins of the mentioned rivers. This project will deepen our knowledge of the connections between land-cover and the hydrological cycle during the Holocene, a period characterized by ever larger human population and land-transformations, in relation to the Asian monsoon system evolution.

Research Theme: A "Ocean and Climate"