Logo Universitat Bremen
Die Inhalte dieser Seite sind leider nicht auf Deutsch verfügbar.

Shuwen Sun

Institution:University of Bremen
Phone:+49 421 218 - 65139
E-mail:[Bitte aktivieren Sie Javascript]
Shuwen Sun

PhD project:

Combined use of δ13C and Δ14C values of lignin oxidation products to trace sources, transportand depositional process of terrestrial particulate organic matter in sediments of the AmazonRiver

Good biomarkers of terrestrial vascular plants include plant wax lipids and lignin. The latter serves as rigidifying constituent in stems and leaves of higher land plants. Both groups of biomarkers have been widely used to study the fate of terrestrial organic carbon in marine environment. However, the parallel utilization of 13C and 14C compositions of lignin-derived phenols is relatively rare compared with that of plant wax lipids. In my PhD project, lignin-derived phenos and their 13C and 14C signature will be employed to provide insights into the sources, transport and distribution of terrestrial organic carbon in sediments of Amazon River and shelf and unravelling the paleoclimate conditions of the Amazon basin.

My project will be based on surface sediment samples collected from the main tributaries of the Amazon River in dry and rainy seasons, and on surface sediments from the Amazon shelf. Furthermore, a sediment core from the Amazon slope will be studied. The main objectives of my research are summarized as follows.
  1. The different methods of compound-specific isotope analysis and radiocarbon analysis of lignin-derived phenols will be employed and compared to each other to find the most suitable one. This part of work is based on standard compounds of lignin-derived phenols and a test sediment sample collected from the Amazon shelf.
  2. On the basis of bulk parameters (TOC, C/N, δ13C of bulk sample), lignin content, δ13C and ages of lignin phenols in sediments from the main tributaries and the Amazon shelf, a new understanding of sources, transport, distribution and deposition of terrestrial organic carbon in the Amazon River and shelf will be obtained.
  3. According to the results of surface sediment analyses, a station will be chosen to conduct a down-core study, which will provide information about the vegetation composition of the Amazon rainforest and the paleoclimatic changes.

Thesis committee:

Prof. Dr. Gesine MollenhauerAlfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI), Bremerhaven
Dr. Enno SchefussUniversity of Bremen
Dr. Marcus ElvertUniversity of Bremen
PD Dr. Matthias ZabelUniversity of Bremen