Warm COCOA
Warming-induced Changes in Organic CarbOn cycling in the Arctic (Warm COCOA)
Deltas are dynamic environments that are subject to dramatic changes on short timescales, making them hotspots for carbon turnover. The Mackenzie River is the largest arctic river of North America with an annual discharge of about 1 Mt of carbon. It is expected that under current accelerated warming the many lakes of the Mackenzie delta, which have connectivity to the main river, will undergo environmental changes under intensified precipitation and earlier melting of ice. A key tool to understand carbon cycling is the radiocarbon composition of specific biomarkers, which enables the detection of mobilized ancient permafrost carbon and its transport and incorporation into different carbon pools. I will study the dynamics of deltaic lake ecosystems over the past century through the application of recently developed molecular (lipid biomarker) and isotopic (radiocarbon and stable isotopes) proxies to lake sedimentary records. This will unravel the impact of old carbon input into aquatic ecosystems. I will develop a novel method to measure the stable and radiocarbon composition of long-chain diols to trace the different pools of carbon in aquatic ecosystems. Furthermore, the effect of the human-induced warming of the last century will be studied via analysis of sediment cores from multiple deltaic lakes.