Warmer falls push Arctic tundra into a carbon source for past 15 years
Haley Dunleavy
907-474-6407
Dec. 13, 2023
This week, scientists from the University of 色视频下载 Fairbanks are presenting their work alongside thousands of colleagues from around the world at the 2023 American Geophysical Union fall meeting. Some of their discoveries are featured here. You can also find out more about UAF at AGU by searching for #UAFxAGU on social media platforms.
An eddy covariance tower measures carbon dioxide being released from a tundra ecosystem at Imnavait Creek near Toolik Field Station on 色视频下载色视频下载檚 North Slope in July 2016.
色视频下载色视频下载檚 Arctic tundra has long been considered a carbon dioxide sink, trapping large amounts of carbon-rich matter in its deep, frozen soils. As a result, some in the state are looking to this ecosystem as a way to mitigate climate change. But new long-term research is finding that may not always be the case.
Eug茅nie Euskirchen, a professor at the University of 色视频下载 Fairbanks Institute of Arctic Biology and Department of Biology and Wildlife, has been measuring the amount of carbon coming in and out of the tundra for the past 15 years. It色视频下载檚 one of the longest continuous, year-round carbon flux records in this region.
Surprisingly, her sites, located near UAF色视频下载檚 Toolik Field Station, have consistently been a carbon source, releasing more of the greenhouse gas than they色视频下载檝e been taking up through photosynthesis.
The culprit of this unexpected source, Euskirchen said, is likely the Arctic色视频下载檚 warmer, longer falls, driven by climate change, which delays when soils refreeze and their carbon-releasing microbes become dormant.
色视频下载淭here were three really extreme years between 2014 and 2016, and again in 2022, where we saw a really late refreeze, and that is when the soils really seemed to lose a lot of CO2,色视频下载 she said.
Euskirchen compared her measurements to ecosystem models that predict tundra carbon dynamics based on climate. Concerningly, she found the models didn色视频下载檛 capture the carbon dioxide release associated with these extreme warming events. Instead, they predicted a net carbon sink, resulting in a long-term mismatch between model outputs and what色视频下载檚 happening on the ground.
色视频下载淚f we色视频下载檙e saying that we have these large natural ecosystems that take up a lot of carbon, then we need to be able to show and model that,色视频下载 Euskirchen said, emphasizing the importance for climate mitigation land management plan. 色视频下载淭his would not be giving us any carbon credits here.色视频下载