Tracking lake ecosystem response to asymmetric arctic warming

• Antragstellerin: Dr. Juliane Wischnewski
• Fachliche Zuordnung: Paläontologie
• Förderung: Förderung von 2013 bis 2017
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 229225839

The rate and asynchrony of recent warming in the Arctic combined with the uncertainty over its ecological consequences are the background to this proposed project, which will investigate change in algae community structure and biodiversity in arctic lakes from Greenland and Siberia. Comprehensive studies, mainly from arctic Canada and Scandinavia, show evidence of biological changes in lake ecosystems concurrent with anthropogenic-induced temperature increase since AD1850. There remains, however, an almost complete lack of information on how the many lake ecosystems in arctic Siberia and Greenland (particularly East Greenland), which account for two thirds of the arctic land mass, have responded to the recent temperature changes. How the different lake ecosystems across the Arctic have responded to climate change, whether they have similar trajectories of change or whether there are differences between the distinctive lake types represented in these arctic regions, is so far very poorly investigated. The proposed study seeks to address this significant knowledge gap by investigating the response of algal communities in lake ecosystems in Greenland and Siberia. Algal communities form the basis of lake food webs and are therefore an ideal starting point to study ecosystem change. To account for spatial heterogeneity, modern and fossil diatom, Pediastrum and pigment assemblages from ~100 lake surface sediment samples and 24 lake sediment cores will be used to reconstruct and evaluate environmental change during the last ~200 years. Site selection will follow the principle of choosing sites that differ in current temperature anomalies, and sites that exhibit different catchment/vegetation characteristics. A set of well-established and more novel statistical methods will be applied to investigate patterns, controls and differences of algae community response, major regime shifts and ecosystem resilience across spatial and temporal scales within and between the two different arctic regions. The proposed study is novel in that it will compare algal community change resulting from both slow and rapid climate warming across regions with different catchment characteristics and biodiversity. Thes comparison of Greenland and Siberia and the large number of lakes covering long biotic and abiotic gradients, provides a unique opportunity to track the nature of across region lake ecosystem response to climate change and contribute to the controversially discussed questions concerning present - day and future arctic warming.

• DFG-Verfahren: Forschungsstipendien
• Internationaler Bezug: Dänemark
• Gastgeber: Professor Erik Jeppesen