Characterization of humic acids from tundra soils of northern Western Siberia by electron paramagnetic resonance spectroscopy

Чуков, С. Н.; Ejarque, Elisabet; Abakumov, Evgeny

doi:10.1134/s1064229317010057

Cited by 23 publications

(23 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The free-radical content was higher in the superficial levels than in the isolated ones. This corresponds well with previous reports (Chukov et al, 2017;Abakumov et al, 2015) that connect the isolation of buried organic matter in the suprapermafrost with declining free-radical content. This reveals the increased biochemical activity of HAs in topsoil.…”

Section: Resultssupporting

confidence: 93%

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from <sup>13</sup>C NMR and electron spin resonance spectroscopy

Abakumov

Alekseev

2018

Solid Earth

View full text Add to dashboard Cite

Abstract. Previously, the structure and molecular composition of the Antarctic soil organic matter (SOM) has been investigated using 13C-NMR methods, which showed that in typical organo-mineral soils the aliphatic carbon prevails over the aromatic one, owing to the non-ligniferous nature of its precursor material. In this study, the SOM was analysed from different sample areas (surface level and partially isolated supra-permafrost layer) of the tundra-barren landscape of the Fildes Peninsula, King George Island, Western Antarctica. We found that the humic acids (HAs) of the cryoturbated, buried areas had lower amounts of alkyl aromatic and protonized aromatic compounds. In contrast, the HAs from the surface layers contain less alkyl carbon components. The free-radical content was higher in the surface layers than in the buried layers due to the presence of fresh organic remnants in superficial soil samples. New data on SOM quality from these two representative Cryosols will enable a more precise assessment of SOM stabilization rate in sub-Antarctic tundras. Comparison of the 13C-NMR spectra of the HAs and the bulk SOM revealed that humification occurs in the Antarctic and results in accumulation of aromatic and carboxylic compounds and reductions in alkylic ones. This indicates that humification is one of the ways of soil organic matter stabilization.

show abstract

Section: Resultssupporting

confidence: 93%

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from <sup>13</sup>C NMR and electron spin resonance spectroscopy

Abakumov

Alekseev

2018

Solid Earth

View full text Add to dashboard Cite

show abstract

“…This reveals the increased biochemical activity of HAs in topsoil. Compared to data from Lupachev (2017), the differences between exposed and isolated areas are less pronounced but, in general, the HAs of the Antarctic soils contain more unstable free radicals on average than the tundra soils of the Kolyma Lowland (Lupachev et al, 2017) and are comparable to the soils from the Yamal tundra (Chukov et al, 2017). Taken together, the free-radical content found in our study was lower than in anthropogenically affected boreal and forest steppe soils of the East European Plain .…”

Section: Resultscontrasting

confidence: 75%

“…Magnesium powder with fixed radical concentration was used as an external standard. The concentration of the paramagnetic centres in powdered samples was determined by comparison to relative signal intensities of the external standard using the program JES-FA swESR v. 3.0.0.1 (JEOL, Japan; Chukov et al, 2017).…”

Section: Sampling and Laboratory Analysismentioning

confidence: 99%

Stability of soil organic matter in Cryosols of Maritime Antarctic: Insights from 13-C NMR and electron spin resonance spectroscopy

Abakumov¹,

Alekseev²

2018

Preprint

View full text Add to dashboard Cite

Abstract. In this study, the soil organic matter (SOM) was analyzed from different sample areas (surface level and partially isolated supra-permafrost layer) of the tundra-barren landscape of the Fildes Peninsula, King George Island, Western Antarctica. We found that the humic acids (HAs) of the cryoturbated, buried areas had lower amounts of alkylaromatic and protonized aromatic compounds. In contrast, the HAs from the surface layers contain less alkyl carbon components. The free radical content was higher in the surface layers than in the buried layers due to the presence of fresh organic remnants in superficial soil samples. New data on SOM quality from these two representative Cryosols will enable more precise assessment of SOM stabilization rate in sub-Antarctic tundras. Comparison of the 13C-NMR spectra of the HAs and the bulk SOM revealed that humification occurs in the Antarctic and results in accumulation of aromatic and carboxylic compounds and reductions in alkylic ones.

show abstract

“…The role of free radicals in soil formation and humification is underestimated (Senesi, ); however, it is known that free radicals take part in step‐by‐step polymerization, which is the basic process of humification. The degree of humification negatively correlates with free radicals content in a zonal environmental gradient (Chukov, Ejaque, & Abakumov, ). Therefore, we can conclude that fire results in events that are opposite to humification—destruction and destabilization of the molecules.…”

Section: Resultsmentioning

confidence: 99%

Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods

2017

View full text Add to dashboard Cite

The effect of wildfires on the soils of the south taiga and forest‐steppe environments of Central Russia (Histic Spodosols and Eutric Fluvic Arenosols) was investigated in terms of the content and quality of humic acids (HAs) using instrumental spectroscopic methods (solid‐state carbon‐13 nuclear magnetic resonance and electron spin resonance). The bulk elemental composition of HAs was not essentially altered in postfire soils; however, the organic matter of fire‐affected superficial soil layers was characterized by changes in the structural composition and biochemical activity levels. Solid‐state carbon‐13 nuclear magnetic resonance spectroscopy showed that there is an intensive increase in aromatic compounds in HA molecules in soil from both the south taiga and forest‐steppe environments. There is a pronounced and statistically significant decline of aliphatic chain content in response to exposure to fire. The free radicals content and the degree of molecular stabilization assessed with electron spin resonance showed an essential alteration of the HAs, expressed in the increase in the radical's portion, in postfire soils compared with that found in soils not exposed to fire. It was also shown that the accumulation of aromatic compounds indicates only apparent stabilization of HAs due to the loss of periphery alkylic carbon species, which was confirmed by destabilization of the molecules as illustrated by the increase of free radicals.

show abstract

Characterization of humic acids from tundra soils of northern Western Siberia by electron paramagnetic resonance spectroscopy

Cited by 23 publications

References 13 publications

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from <sup>13</sup>C NMR and electron spin resonance spectroscopy

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from <sup>13</sup>C NMR and electron spin resonance spectroscopy

Stability of soil organic matter in Cryosols of Maritime Antarctic: Insights from 13-C NMR and electron spin resonance spectroscopy

Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods

Contact Info

Product

Resources

About

Characterization of humic acids from tundra soils of northern Western Siberia by electron paramagnetic resonance spectroscopy

Cited by 23 publications

References 13 publications

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from &lt;sup&gt;13&lt;/sup&gt;C NMR and electron spin resonance spectroscopy

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from &lt;sup&gt;13&lt;/sup&gt;C NMR and electron spin resonance spectroscopy

Stability of soil organic matter in Cryosols of Maritime Antarctic: Insights from 13-C NMR and electron spin resonance spectroscopy

Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods

Contact Info

Product

Resources

About

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from <sup>13</sup>C NMR and electron spin resonance spectroscopy

Stability of soil organic matter in Cryosols of the maritime Antarctic: insights from <sup>13</sup>C NMR and electron spin resonance spectroscopy