Sources, degradation, and thermal stability of organic matter in riparian soils along two major rivers of China

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena Pub Date : 2025-02-05 DOI:10.1016/j.catena.2025.108783

Le Wang , Peng Yao , Zheng Wang , Bin Zhao , Nan Wang , Xiwen Ye , Chao Gao

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引用次数: 0

Abstract

Riparian zones function as critical interfaces for the cycling of organic matter (OM) among terrestrial, aquatic, and oceanic environments. However, the characteristics of OM in riparian soils are not yet well understood. This study examined total organic carbon (TOC), stable carbon isotopic composition (δ¹³C), lignin phenols, and thermal gravimetric properties of OM in riparian soils along the Changjiang and Huanghe. The primary objective of this study was to enhance our understanding of the sources, distribution, degradation, and thermal stability of soil OM in these two major river systems in China. The TOC and lignin contents (Λ₈) in riparian soils along the Changjiang were found to be relatively higher than those in the Huanghe soils. Both river systems exhibited considerable spatial heterogeneity and seasonal variability. Analyses of δ¹³C, carbon-to-nitrogen (C/N) ratios, and Λ₈ indicate that the OM in the soils of both river systems primarily originates from terrestrial higher plants and aquatic vegetation, but modified by microbial processes. However, the lignin decay parameters and the ratios of TOC and Λ₈ to specific surface area (SSA) suggest that the degradation of OM in these soils is less extensive compared to that in riverine particulate matters and coastal sediments. This indicates a substantial loss of terrestrial OM and an addition of marine OM during the transport from soils to rivers and estuaries. The carbon reactivity index (CRI) of the soils, as determined by thermogravimetric analysis, ranged from 50% to 100%, which is generally lower than that observed in coastal sediments, suggesting that the OM in these soils exhibits greater thermal reactivity. This study addresses a critical knowledge gap regarding the lignin and thermal stability of OM in China’s terrestrial ecosystems, providing a foundation for a better understanding of the fate of terrestrial OM as it transitions from land to ocean.

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来源期刊

Catena 环境科学-地球科学综合

CiteScore

10.50

自引率

9.70%

发文量

816

审稿时长

54 days

期刊介绍： Catena publishes papers describing original field and laboratory investigations and reviews on geoecology and landscape evolution with emphasis on interdisciplinary aspects of soil science, hydrology and geomorphology. It aims to disseminate new knowledge and foster better understanding of the physical environment, of evolutionary sequences that have resulted in past and current landscapes, and of the natural processes that are likely to determine the fate of our terrestrial environment. Papers within any one of the above topics are welcome provided they are of sufficiently wide interest and relevance.