Fluorescence spectroscopy studies of humic substance fractions isolated from permanently frozen sediments of Yakutian coastal lowlands

Shirshova, L. T.; Kholodov, Alexander; Zolotareva, B. N.; Fominykh, L. A.; Yermolayev, A. M.

doi:10.1016/j.geoderma.2008.11.026

Cited by 11 publications

(5 citation statements)

References 24 publications

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“…The upper layers of the undisturbed yedoma core under study (Units 2 and 3) contained much more degraded OM with the higher humification index (C HA /C FA ratio) as compared to the deep permafrost layers from Unit 1 (13–15 m). This is consistent with reports of a higher transformation rate of OM in the upper layers of the yedoma deposits as compared to the deeper ones (Shirshova et al, ). Still, the highest value for the humification index (up to 7) was observed for OM in the deep layer of the alas core, which reflects the greater humification degree of the alas OM as compared to the yedoma OM.…”

Section: Discussionsupporting

confidence: 93%

The Molecular Composition of Humic Substances Isolated From Yedoma Permafrost and Alas Cores in the Eastern Siberian Arctic as Measured by Ultrahigh Resolution Mass Spectrometry

et al. 2019

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Ongoing climate change is making the large pool of organic matter (OM) stored in Arctic permafrost vulnerable to mobilization; thus, garnering a deeper understanding of molecular transformations within the abundant pool of soil OM, specifically humic substances, is crucial. Here we present the first high-resolution mass-spectrometry examination of molecular compositions of humic acid (HA) and fulvic acid (FA) isolated from organic-rich deep yedoma (Pleistocene age ice-rich permafrost) and alas (thermokarst deposit formed during permafrost thaw) cores. The FA fractions were dominated by oxygen-rich unsaturated compounds, whereas the HA fractions were mostly composed of relatively reduced saturated and aromatic moieties. A substantial increase in contribution of both CHO-only and N-containing aliphatic compounds was observed in the HA fractions of the yedoma OM with depth, whereas the alas HA fractions were depleted in aliphatics but enriched with condensed and hydrolyzable tannins. The observed differences in compositional space of the immobile OM stored in the deep yedoma versus alas deposits were consistent with evolution of OM during thermokarst lake genesis, implying intense microbial degradation of N-rich OM released from the yedoma deposits and accumulation of highly degraded, plant-derived OM. The patterns of molecular transformations of OM were apparent in compositional space of the least degraded HA fractions as compared to much more oxidized FA fractions. This shows great promise of molecular exploration of the alkali-extracted OM, comprising up to 50% of the total organic carbon in deep permafrost both for paleoreconstructions and predictions of climate feedback to released OM due to permafrost thaw.

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Section: Discussionsupporting

confidence: 93%

The Molecular Composition of Humic Substances Isolated From Yedoma Permafrost and Alas Cores in the Eastern Siberian Arctic as Measured by Ultrahigh Resolution Mass Spectrometry

et al. 2019

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“…Changes in the intensity and the position of characteristic peaks in synchronous scan spectra depend on the degree of humification and the chemical structure of the analyzed substances (Hur Shirshova et al, 2009). The percentage share of each of the components responsible for the presence of the characteristic band in the analyzed spectra was calculated as the area under the fluorescence spectrum (integral fluorescence intensity).…”

Section: Synchronous Scan Spectramentioning

confidence: 99%

“…Although fluorophore groups are present in small amounts in HS macromolecules, the analysis of fluorescence spectra provides a lot of valuable information on the spatial structure related to the degree of their polymerization and polycondensation, as well as the intermolecular and intramolecular SOM interactions (Boguta, Pieczywek, & Sokołowska, 2016;J. Chen, Gu, LeBoeuf, Pan, & Dai, 2002;Fuentes, Gonzalez-Gaitano, & Garcia-Mina, 2006;Miano & Senesi, 1992;Poulin et al, 2014;Senesi, 1990;Shirshova, Kholodov, Zolotareva, Fominykh, & Yermolayev, 2009;Yan, Fu, Li, Gao, & Wang, 2013).…”

Section: Introductionmentioning

confidence: 99%

Fluorescence properties of humic substances transformed in ectohumus horizons of Podzols affected by alkaline fly‐ash

et al. 2021

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“…Standards of humic substances are generally used in solution as model of a part of the soils organic matter. In solution they fluoresce for an excitation of 250 nm and 350 nm, with an emission from 400 to 450 nm, depending on soils origin [12,25]. Few studies were done on their fluorescence in solid state [20] and no exhaustive exploration was done until now.…”

Section: Introductionmentioning

confidence: 99%

Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system

Mounier

Nicolodelli

Redon

et al. 2017

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model.

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Fluorescence spectroscopy studies of humic substance fractions isolated from permanently frozen sediments of Yakutian coastal lowlands

Cited by 11 publications

References 24 publications

The Molecular Composition of Humic Substances Isolated From Yedoma Permafrost and Alas Cores in the Eastern Siberian Arctic as Measured by Ultrahigh Resolution Mass Spectrometry

The Molecular Composition of Humic Substances Isolated From Yedoma Permafrost and Alas Cores in the Eastern Siberian Arctic as Measured by Ultrahigh Resolution Mass Spectrometry

Fluorescence properties of humic substances transformed in ectohumus horizons of Podzols affected by alkaline fly‐ash

Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system

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