QUantifying the Impact of vegetation succession on Carbon dynamics in arctic DRAINed lake basins (QUIC-DRAIN)

• Applicant: Dr. Juliane Wolter
• Subject Area: Physical Geography
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 459818777

The main goals of QUIC-DRAIN are (i) to quantify carbon storage in drained thermokarst lake basins and its relation to changes in vegetation, and (ii) to upscale these findings to the regional scale to identify potential current and future GHG emission hotspots. It will conduct field surveys of surface sediment and vegetation and sediment coring from the Lena Delta across Alaska to the western Canadian Arctic. QUIC-DRAIN will follow an interdisciplinary approach combining laboratory analyses of organic matter and plant macrofossils, incubation experiments, remote sensing, and machine learning-aided upscaling techniques. Thaw of ice-rich permafrost may create water-filled depressions in the landscape, the so-called thermokarst lakes. These lakes are ubiquitous in Arctic lowlands from Siberia to the western Canadian Arctic (Beringia), and drain frequently. After drainage, the lake sediment generally refreezes, wetlands develop and pioneer vegetation colonizes the basins. Thermokarst lakes are important contributors to greenhouse gas emissions from arctic lowlands because of increased microbial activity in thawed zones beneath them. Permafrost refreezing after lake drainage may potentially limit these emissions. Yet, data on vegetation succession, organic matter composition and carbon storage, and even drainage frequencies are extremely scarce and spatial coverage is low. Estimations of carbon contribution from permafrost regions to the atmosphere must include reliable data from drained thermokarst lake basins, which is currently missing. QUIC-DRAIN will fill this knowledge gap by focussing on three objectives:1 Defining the timing, spatio-temporal patterns and drivers of Holocene thermokarst lake drainage2 Assessing vegetation succession and carbon dynamics following drainage at plot-scale 3 Upscaling carbon pools and cycling in different vegetation succession stages to regional scale and identifying potential future GHG production hotspotsThese objectives will be addressed by reconstructing drainage ages and environmental drivers of drainage using remote sensing and sediment cores from drained lake basins (O1). It will study post-drainage vegetation succession, organic matter properties and vegetation-organic matter relationships in sediment cores as well as in surveys of vegetation and surface sediment (O2). Finally, QUIC-DRAIN will upscale these findings to region scale using remote sensing and machine-learning techniques, with remotely sensed land cover as a proxy for carbon dynamics (O3). QUIC-DRAIN is unique in that it specifically targets past and present drainage events and the environmental conditions following them across large regions. The project will be based at the University of Potsdam, which is a strong contender in Geoscience, Biology and data science, thus combining all three main research areas of the project.

• DFG Programme: Research Grants