Warming accelerates the decomposition of root-derived hydrolysable lipids in a temperate forest and is depth- and compound class-dependent

作者：Binyan Sun, Cyrill Zosso, Guido L. B. Wiesenberg, Elaine Pegoraro, Margaret Torn, Michael W. Schmidt · 发表于：SOIL · 年份：2025 · DOI：10.5194/soil-11-1077-2025 · 被引用次数：2 · 研究领域：Soil Carbon and Nitrogen Dynamics、Biocrusts and Microbial Ecology、Soil erosion and sediment transport

Abstract. Global warming could potentially increase the decomposition rate of soil organic matter (SOM), not only in the topsoil (<20 cm) but also in the subsoil (>20 cm). Despite its low carbon content, subsoil holds on average nearly as much SOM as topsoil across various ecosystems. However, significant uncertainties remain regarding the impact of warming on SOM decomposition in subsoil, particularly root-derived carbon, which serves as the primary organic input at these horizons. In a whole-soil field warming experiment at Blodgett Forest Research Station (California, USA), we investigated whether warming accelerates the decomposition of root-derived hydrolysable lipids in the top- (10–14 cm) and subsoil (45–49, 85–89 cm) by using molecular markers and in-situ incubation of 13C-labeled root litter at each depth. Our results reveal that at compound-class level, hydrolysable lipids presented compound-dependent responses. Warming consistently reduced fatty acid mass change across soil depths, particularly at 85–89 cm. In subsoil, there was accumulation of fatty acids, which primarily originated from microbial-derived mid-chain fatty acids such as octadecanoic acid (C18:0 fatty acids), octadecenoic acid (C18:1 fatty acids), and hexadecanoic acid (C16:0 fatty acids). Higher temperature attenuated this accumulation, indicating less microbial transformation of root-derived carbon under warming. At monomer level, ω-hydroxy acids and diacids as suberin markers were more resis...