Jonathan A. O’Donnell Michael P. Carey Sarah M. Laske Xiaomei Xu Kenneth H. Dunton Vanessa R. von Biela Ashley E. Stanek 2024 <div class="abstract-group "><div class="article-section__content en main"><p>Climate change alters the sources and age of carbon in Arctic food webs by fostering the release of older carbon from degrading permafrost. Radiocarbon (¹⁴C) traces carbon sources and age, but data before rapid warming are rare and limit assessments over time. We capitalized on<span>&nbsp;</span>¹⁴C data collected ~ 40 years ago that used fish as natural samplers by resampling the same species today. Among resampled fish, those using freshwater food webs had the oldest<span>&nbsp;</span>¹⁴C ages (&gt; 1000 yr BP), while those using marine food webs had the youngest<span>&nbsp;</span>¹⁴C ages (near modern). One migratory species encompassed the entire range of<span>&nbsp;</span>¹⁴C ages because juveniles fed in freshwater streams and adults fed in offshore marine habitats. Over ~ 40 yr, average<span>&nbsp;</span>¹⁴C ages of freshwater and marine feeding fish shifted closer to atmospheric values, suggesting a potential influence from “greening of the Arctic.”</p></div></div> application/pdf 10.1002/lol2.10442 en Association for the Sciences of Limnology and Oceanography Arctic fishes reveal patterns in radiocarbon age across habitats and with recent climate change article