摘要：Heating temperature (HT) during forest fires is a critical factor in regulating the quantity and quality of pyrogenic dissolved organic matter (DOM). However, the temperature thresholds at which maximum amounts of DOM are produced (TTmax) and at which the DOC gain turns into net DOC loss (TT0) remain unidentified on a component-specific basis. Here, based on solid-state C-13 nuclear magnetic resonance, absorbance and fluorescence spectroscopies, and Fourier transform ion cyclotron resonance mass spectrometry, we analyzed variations in DOM composition in detritus and soil with HT (150-500 degrees C) and identified temperature thresholds for components on structural, fluorophoric, and molecular formula levels. TTmax was similar for detritus and soil and ranged between 225 and 250 degrees C for bulk dissolved organic carbon (DOC) and most DOM components. TT0 was consistently lower in detritus than in soil. Moreover, temperature thresholds differed across the DOM components. As the HT increased, net loss was observed initially in molecular formulas tentatively associated with carbohydrates and aliphatics, then proteins, peptides, and polyphenolics, and ultimately condensed aromatics. Notably, at temperatures lower than TT0, particularly at TTmax, burning increased the DOC quantity and thus might increase labile substrates to fuel soil microbial community. These composition-specific variations of DOM with temperature imply nonlinear and multiple temperature-dependent wildfire impacts on soil organic matter properties.

关键字：soil organic matter; black carbon; heating temperature; thermogenic dissolved organic matter; spectroscopic characteristics; Fourier transform ion cyclotron resonance mass spectrometry

ISSN号：0013-936X

卷、期、页：卷57期45: 17291-17301

发表日期：2023-11-02

期刊分区（SCI为中科院分区）：一区

收录情况：SCI（科学引文索引印刷版）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：ENVIRONMENTAL SCIENCE & TECHNOLOGY

参与作者：张强,王映辉,关萍,张鹏,莫小涵,尹格格,曲波,徐树军,张干,Dittmar, Thorsten,王俊坚

第一作者：何晨,史权

论文类型：期刊论文

论文概要：张强,王映辉,关萍,张鹏,莫小涵,尹格格,曲波,徐树军,何晨,史权,张干,Dittmar, Thorsten,王俊坚，Temperature Thresholds of Pyrogenic Dissolved Organic Matter in Heating Experiments Simulating Forest Fires，ENVIRONMENTAL SCIENCE & TECHNOLOGY，2023，卷57期45: 17291-17301

论文题目：Temperature Thresholds of Pyrogenic Dissolved Organic Matter in Heating Experiments Simulating Forest Fires