LTREB Renewal: The reorganization and resynchronization of biogeochemical cycles after an unprecedented tundra fire

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

Fire has been historically rare in the Arctic tundra, but is projected to increase in severity and frequency in a future warmer world. The rarity of fires in this biome has made it challenging to measure, understand, and predict the consequences of fire on important ecosystem services such as species diversity and ecosystem carbon cycling. Furthermore, the impacts of fire last a long time-- years to decades-- by altering critical biogeochemical cycles that are important for long term ecosystem recovery. Since fire severity can dramatically reduce soil nutrient availability, it is hypothesized that ecosystem recovery is dependent on both burn severity and post-fire soil resources. This project continues a ten-year project studying the effects of fire on terrestrial carbon cycling in Alaskan tundra ecosystems. The research combines long-term ecological observations, a nutrient addition experiment, and improvement of an ecosystem model. Training and workforce relevant skills for both undergraduate students and graduate students are being provided. A children’s book will be published to reach the general public, as well as a YouTube video. A large amount of data about ecosystem processes is being contributed to public databases. This research will acquire and synthesize a multi-decadal record (2008-2026) of ecosystem function from the unprecedented 2007 Anaktuvuk River fire on the North Slope of Alaska. Eddy covariance fluxes and biomass harvests will measure temporal changes in ecosystem carbon fluxes and stocks across a burn severity gradient (Severe-, Moderate-, and Un-burned tundra), while nutrient fertilization experiments at the Severe- and Un-burned tundra sites will determine the role of nutrient availability on the rate of ecosystem recovery. These records will inform a coupled biogeochemical model (i.e. the Multiple Element Limitation [MEL] model) to improve predictions of the long term impacts of fire on Arctic ecosystem carbon cycling. The development of the MEL model will provide a powerful tool for scientists, land managers, and policy makers to quantify the future impacts of fire in this rapidly-changing region. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.