Collaborative Research: Impacts of Climate Seasonality on Carbon Accumulation and Methane Emissions of Alaskan Ecosystems during the Holocene Thermal Maximum

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The Arctic has been experiencing great warming and ecological changes in recent decades. The last pronounced warm period occurred about 11,000-9,000 years ago in Alaska. The warm and possibly dry climate resulted in unusual ecosystem types and processes, including novel poplar-willow deciduous forests in uplands, and rapid peatland expansion and growth in lowlands. The proposed research will test the hypothesis that the enhanced climate seasonality at that time played a major role in causing such contrasting responses of ecosystems on uplands and wetlands. To look into the past, the researchers will analyze microfossils preserved in peat. They will integrate their findings and test the hypothesis using simulation modeling. The project's objectives are to document ecosystem changes that occurred 10,000 years ago across Alaska and to assess effects of a warmer climate and different seasonality on nutrient and water cycling using the Terrestrial Ecosystem Model. This research addresses an important topic in global change, how a warming climate will interact with changing precipitation to influence ecosystem structure and functioning in the Arctic. An improved ability to model ecosystem processes will allow for better prediction of changes in carbon cycling under a changing climate in Alaska, and potentially for Pan-Arctic ecosystems in the future. In response to the public's keen interest in Arctic warming and its biological impacts, the investigators will disseminate results through the popular press. Undergraduates, graduate students, and a postdoctoral researcher will be trained on this project.