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Ultraviolet humic-like component contributes to riverine dissolved organic matter biodegradation
Ni, Maofei1,3,4; Li, Siyue2,4
2023-02-01
摘要Biological degradation of dissolved organic matter (DOM) regulates its structure and fate in river ecosystems. Previous views suggested that labile components were dominantly consumed by microbial metabolism. Here we provide new observations that a part of recalcitrant compounds largely contribute to riverine DOM biodegradation. The excitation emission matrix fluorescent spectroscopy combined with peak picking and parallel factor analysis are used to explore component variability during DOM incubation. Humic-like and tryptophan-like DOM are the primary components of riverine DOM, with proportion contributions of 39%???82% and 16%???61% for % of the maximum fluorescence intensity, respectively. After 56 days of aerobic incubation in the dark, large amounts of tyrosine-like DOM generation are observed. Elevated temperature enhances the decomposition of ultraviolet humiclike substance and further stimulates labile DOM bio-mineralization into carbon dioxide. Meanwhile, averaged proportions of amino acid compositions (peak B and T) markedly increase ( p < 0.05) as the humic-like compositions (peak A, M and C) decrease after DOM incubation, suggesting incomplete degradation of refractory DOM from high-molecular to low-molecular weight compounds. The findings support the new notion of the continuous DOM biodegradation in a mode as ???steps by steps???, contributing to a new understanding of carbon cycling for the UN Sustainable Development Goal. ?? 2022 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
关键词Dissolved organic matter (DOM) Sequential biodegradation Recalcitrant compounds Component and fate Fluorescence analysis
DOI10.1016/j.jes.2021.10.011
发表期刊JOURNAL OF ENVIRONMENTAL SCIENCES
ISSN1001-0742
卷号124页码:165-175
通讯作者Li, Siyue(syli2006@163.com)
收录类别SCI
WOS记录号WOS:000797162500009
语种英语