Soil organic matter composition along altitudinal gradients in permafrost affected soils of the Subpolar Ural Mountains

Дымов, А. А.; Жангуров, Е. В.; Hagedorn, Frank

doi:10.1016/j.catena.2015.03.020

Cited by 25 publications

(10 citation statements)

References 44 publications

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“…The comparative analyses of molecular structure and elemental composition show that FAs are enriched in oxygen components, which determine increased hydrophilicity and ability to migrate in aqueous solutions (Table 3). Similar results were obtained previously for soils of Alaska [23] and the Ural Mountains [24]. The high relative content of carboxylic groups in FAs would increase their migration ability and biogeochemical activity in Polar terrestrial ecosystems.…”

Section: Resultssupporting

confidence: 88%

¹³C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands

Abakumov

Лодыгин

Томашунас

2015

International Journal of Ecology

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Humic acids (HAs) and fulvic acids (FAs) of two Polar soils were investigated by13C NMR and ESR spectroscopies, investigating the degree of humification and the molecular structure. One soil, from Bolshoi Lyakhovsky Island, contains two humus horizons: modern and buried. The other soil, from Wrangel Island, had only one modern humus horizon. The HAs and FAs of the two soils investigated show essential differences. The HAs show fewer oxygen-containing groups in comparison with the FAs, whereas the degree of aromaticity is two or three times higher in the HAs. The13C NMR data also show that HAs are very different from FAs in terms of their molecular composition and hydrophobicity. Humification in the Arctic is limited by the very low content of lignin-derived compounds, due to the restricted vascular flora. As a result, the HAs, isolated from Polar soils, are more similar to the corresponding FAs than to the typical HAs of temperate soils. This was confirmed by ESR data, which show similar levels of free radical concentration for HAs and FAs and are related to the low level of aromaticity of both materials investigated. Apparently, the humification process in the soils of Polar Arctic deserts is in an initial stage.

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Section: Resultssupporting

confidence: 88%

¹³C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands

Abakumov

Лодыгин

Томашунас

2015

International Journal of Ecology

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“…Previous studies have found that the alkyl C and aromatic C concentrations of SOC vary among sites. For example, higher alkyl (~60%) and lower aromatic C (~19%) levels of the SOC were observed in an untouched forest soil in the northern part of the Subpolar Urals 54 and a significantly lower alkyl C (~10%) and higher aromatic C (~30%) of SOC were measured in the soil of Spanish oak forests 55 . Different alkyl C and aromatic C proportions among the study sites are probably explained by differences in plant functional types, microbial community structure, climate, and soil parent material.…”

Section: Discussionmentioning

confidence: 97%

Recalcitrant carbon components in glomalin-related soil protein facilitate soil organic carbon preservation in tropical forests

Zhang

Tang

Zhong

et al. 2017

Sci Rep

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Glomalin-related soil protein (GRSP) is known as an important microbial by-product which is crucial for preserving or accumulating soil organic carbon (SOC). However, the underlying mechanisms are not well understood. In this study, we investigated the chemical structures of GRSP and its relationship with SOC using 13C nuclear magnetic resonance (NMR) in three tropical forests. The three forests, including a planted forest (PF), a secondary forest (MF) and a primary forest (BF), were selected to represent the natural successional process after disturbance in southern China. Results showed that the average concentrations of GRSP were (3.94 ± 1.09) mg cm−3 and accounting for (3.38 ± 1.15)% of the SOC in the top 10 cm soil. NMR analysis indicated rich aromatic C (~30%) and carboxyl C (~40%) in GRSP, and abundant alkyl C (~30%) and O-alkyl C (~50%) in SOC. The recalcitrance indexes (RI), as defined as the ratio of sum of alkyl C and aromatic C over sum of O-alkyl C and carboxyl C, was (98.6 ± 18.9)%, (145.5 ± 10.9)% and (20.7 ± 0.3)% in GRSP higher than that in SOC in the PF, MF and BF, respectively. This study demonstrated that the stubborn structure of GRSP probably regulate the resistance of SOC sequestration in tropical forests, especially in the planted and secondary forests.

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“…Although the SOC densities showed relatively less variations with depth (Figure ), the upper 10 cm of soil in the control and exposed stages showed much higher organic carbon mineralization rates than the deeper soil layers. This result could be explained by the higher labile organic carbon contents that usually decrease with depth [ Dymov et al ., ] (i.e., the upper 10 cm of the control soils and exposed soils has higher labile organic matter contents). In contrast, some of these fractions were lost in drape stage, which resulted in less variation of the accumulative CO 2 production with depth.…”

Section: Discussionmentioning

confidence: 99%

Carbon loss and chemical changes from permafrost collapse in the northern Tibetan Plateau

Zhang

et al. 2016

JGR Biogeosciences

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Permafrost collapse, known as thermokarst, can alter soil properties and carbon emissions. However, little is known regarding the effects of permafrost collapse in upland landscapes on the biogeochemical processes that affect carbon balance. In this study, we measured soil carbon and physiochemical properties at a large thermokarst feature on a hillslope in the northeastern Tibetan Plateau. We categorized surfaces into three different microrelief patches based on type and extent of collapse (control, drape, and exposed areas). Permafrost collapse resulted in substantial decreases of surface soil carbon and nitrogen stocks, with losses of 29.6 ± 4.2% and 28.9 ± 3.1% for carbon and nitrogen, respectively, in the 0-10 cm soil layer. Laboratory incubation experiments indicated that control soil had significantly higher CO 2 production rates than that of drapes. The results from Fourier transform infrared spectroscopy analysis showed that exposed soils accumulated some organic matter due to their low position within the feature, which was accompanied by substantial changes in the chemical structure and characteristics of the soil carbon. Exposed soils had higher hydrocarbon and lignin/phenol backbone content than in control and drape soils in the 0-10 cm layer. This study demonstrates that permafrost collapse can cause abundant carbon and nitrogen loss, potentially from mineralization, leaching, photodegradation, and lateral displacement. These results demonstrate that permafrost collapse redistributes the soil organic matter, changes its chemical characteristics, and leads to losses of organic carbon due to the greenhouse gas emission.Permafrost collapse including thaw slumps can occur rapidly in permafrost regions and result in the release of greenhouses gases, particulates, and dissolved organic carbon [Jensen et al., 2014]. In addition, dissolved organic carbon can be released from thawing permafrost [Cory et al., 2013; Wickland et al., 2007], and MU ET AL. PERMAFROST COLLAPSE CAUSED CARBON LOSS

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Soil organic matter composition along altitudinal gradients in permafrost affected soils of the Subpolar Ural Mountains

Cited by 25 publications

References 44 publications

¹³C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands

¹³C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands

Recalcitrant carbon components in glomalin-related soil protein facilitate soil organic carbon preservation in tropical forests

Carbon loss and chemical changes from permafrost collapse in the northern Tibetan Plateau

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Soil organic matter composition along altitudinal gradients in permafrost affected soils of the Subpolar Ural Mountains

Cited by 25 publications

References 44 publications

13C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands

13C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands

Recalcitrant carbon components in glomalin-related soil protein facilitate soil organic carbon preservation in tropical forests

Carbon loss and chemical changes from permafrost collapse in the northern Tibetan Plateau

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¹³C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands

¹³C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands