Vegetation reconstruction during the last millennium – derived by a lacustrine pollen record from Northern Siberia (Chatanga, Russia)

• Main Author: Schreiber, Xenia
• Format: Thesis
• Language: unknown
• Published: Technische Universität Dresden 2014
• Subjects: Alfred Wegener Institute; Taimyr; Tundra; Siberia
• Online Access: https://epic.awi.de/id/eprint/42129/; https://epic.awi.de/id/eprint/42129/1/Xenia_Schreibe_Master-Thesis.pdf; https://hdl.handle.net/10013/epic.48887; https://hdl.handle.net/10013/epic.48887.d001

Northern Central Siberia is sparsely investigated even the area is provides many suitable archives for palaeoenvironmental studies. Studies are needed to understand the reaction of the highly sensible ecosystem to environmental dynamics and build the basic for ongoing research. The objective of this thesis is to reconstruct the vegetation development at 72°N in Arctic Siberia and to deduce environmental reasons for the changes in the vegetation cover. Sediment samples from a small lake in the vicinity of Chatanga on the Taimyr Peninsula were prepared for light microscopy and pollen analyses were conducted at the Alfred-Wegener-Institute for Polar and Marine Research in Potsdam. The ages of the upper samples were determined by the Environmental Radioactivity Research Centre at the University of Liverpool and deductively ascertained for the rest of the core. The dataset of the pollen count was used to generate highly resolved pollen diagrams of the last millennium: one entire pollen diagram for all taxa, which have been counted throughout the short core, and the other pollen diagram, pollen influx diagram and Iversendiagram for the primary taxa. Statistical analyses were performed to verify significant pollen assemblage zones and to construct synthetic environmental gradients. The pollen assemblages are reflecting three phases of vegetation development during the last millennium, which correspond to the termination of the Medieval Warm Period to the subsequent Little Ice Age and to the Recent Warming period. The Medieval Warm Period reaches till 1308 AD and is predominantly characterized by the regression of Alnus pollen, whereby the percentages of Cyperaceae pollen are increasing. Betula and the herb species do not show comparably trends. The mild climate of the Medieval Warm Period became cooler and drier, which is reflected by the decrease of Alnus pollen so that the dense canopy of the shrub tundra became more lightly and sedges established the light places during the termination of the Medieval Warm Period to ...