Stabilization of organic carbon isolated from cryoconite holes in polar and mountain systems by 13С NMR spectroscopy

2021 ◽  
Author(s):  
Vjacheslav Polyakov ◽  
Evgeny Abakumov
Keyword(s):  
Carbon Dioxide ◽  
Organic Matter ◽  
Nmr Spectroscopy ◽  
Humic Acids ◽  
Carbon Dioxide Emissions ◽  
Heterogeneous Systems ◽  
Basic Research ◽  
13C Nmr Spectroscopy ◽  
The Arctic ◽  
Additional Contribution

<p>Black carbon is one of the short-lived climatically significant factors. This term refers to climate-forming substances that are located for a short amount of time in the atmosphere - from several days to several years. To identify the role of cryoconite in the conditions of a possible climatic crisis, the stabilization of organic matter isolated from cryoconite holes was assessed. Humic acids are part of the organic matter accumulating in soils and cryoconites and are heterogeneous systems of high-molecular condensed compounds formed as a result of the decomposition of organic remains of plants and animals in terrestrial and aquatic ecosystems. Climatic parameters, precursors of humification, and the local position in the landscape determine the diversity of the composition and properties of HAs. Stabilization of organic material is defined as the transformation of organic matter into a state inaccessible to soil microorganisms, and the very property of stabilization is a characteristic stage in the dynamics of carbon. Using 13C NMR spectroscopy, we determined the proportion of aromatic and aliphatic compounds in the composition of HAs in order to assess the stabilization of organic matter in cryoconites from Mount Elbrus (Caucasus Mountains, Russia), the Arctic (Severnaya Zemlya archipelago, Russia) and Antarctica (King George Island, West Antarctica).</p><p>Samples for qualitative analysis of carbon accumulated in cryoconites were carried out during fieldwork in 2020. The studied samples were analyzed at the Department of Applied Ecology, St. Petersburg State University. Humic acids (HAs) were extracted from each sample according to a published IHSS protocol. Solid-state CP/MAS <sup>13</sup>C-NMR spectra of HAs were measured with a Bruker Avance 500 NMR spectrometer.</p><p>Thus, it follows from the obtained results that aliphatic fragments of humic acids predominate in all studied cryoconites. A similar composition of humic acids testifies to a single mechanism of accumulation and development of organic matter in glacier regions. Low biological activity and climatic features prevent condensation of high-molecular compounds in the organic matter of cryoconite holes. This is an essential prerequisite for high rates of carbon dioxide emissions into the atmosphere under the conditions of deglaciation of the studied regions. With the thawing of glaciers and the ingress of cryoconites into warmer conditions, an additional contribution of carbon dioxide to the atmosphere can occur and, therefore, increase the possible climate crisis on our planet.</p><p>This study was supported by Russian Foundation for Basic Research No. 19-05-50107.</p>

scholarly journals Stabilization of organic material from soils and soil-like bodies in the Lena River Delta (13C-NMR spectroscopy analysis)

2020 ◽  
Vol 10 ◽  
Author(s):  
Vyacheslav Polyakov ◽  
Evgeny Abakumov
Keyword(s):  
Nmr Spectroscopy ◽  
Humic Acids ◽  
Soil Layer ◽  
13C Nmr Spectroscopy ◽  
River Delta ◽  
The Arctic ◽  
Polar Regions ◽  
Alluvial Deposits ◽  
Lena River ◽  
Lena River Delta

The Arctic ecosystem has a huge reservoir of soil organic carbon stored in permafrost-affected soils and biosediments. During the short vegetation season, humification and mineralization processes in the active soil layer result in the formation of specific soil organic substances – humic substances. Humic acids are high molecular, specific, thermodynamically stable macromolecules. The study was conducted in the Lena River Delta, the largest river delta located in the Arctic. Cryosol-type soils on alluvial deposits of the river form an area of about 45 thousand km<sup>2</sup> under permafrost conditions. The vegetation cover is represented by moss-lichen communities with the presence of <em>Salix glauca</em> in the flooded areas, as well as <em>Betula nana</em> in the areas not subject to flooding. The paper presents the elemental and molecular composition of humic acids isolated from soils, integral indicators of humification (stabilization) of organic matter in the soils of the Lena River Delta. The study was conducted using the <sup>13</sup>C (CP/MAS) NMR spectroscopy method. In the work, it was revealed that up to 33% of aromatic and up to 15% COOR fragments are accumulated in humic acids. The AR/AL ratio ranged from 0.69 to 0.89. The studied soils are variants of modern soil formation (not subjected to alluvial processes) and soil-like bodies that melted from the IC of the river delta. A relatively high degree of condensation of humic acid macromolecules in comparison with other polar regions of the Arctic and Antarctic was noted.

Characterisation of humic acids, isolated from selected sub-antarctic soils by 13C-NMR spectroscopy

2017 ◽  
Vol 7 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Evgeny Abakumov
Keyword(s):  
Organic Matter ◽  
Nmr Spectroscopy ◽  
Humic Acids ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Fildes Peninsula ◽  
Antarctic Soils ◽  
West Antarctic ◽  
The Antarctic

Soils of Antarctic considered as underestimated in terms of soils organic matter polls, organic remnants humification/mineralization rates and biogenic-abiogenic interactions. Humic acids of selected Sub Antarctic soils were investigated in terms of elemental and structural composition with special reference to evaluation of organic matter stabilisation degree and assessment of carbon species distributions in the molecules with use of solid state 13C-NMR spectroscopy. It was shown, that the prevailing of aliphatic compounds on the aromatic one is more pronounced in Antarctic soils than in Arctic ones. Average portion of the aromatic compounds is about 20% in humic acids, extracted from soils with evident ornitogenic effect from Fildes Peninsula (Norh-West Antarctic peninsula). This indicates that the role of humification precursors composition is the leading in the humification process. The stabilisation rate of the Antarctic HAs can be assessed as low and the potential risk of biodegradation of their molecules are high.

scholarly journals Stability and biodegradability of humic substances from Arctic soils of Western Siberia: insights from <sup>13</sup>C-NMR spectroscopy and elemental analysis

2015 ◽  
Vol 7 (4) ◽  
pp. 3021-3052 ◽  
Author(s):  
E. Ejarque ◽  
E. Abakumov
Keyword(s):  
Organic Matter ◽  
Nmr Spectroscopy ◽  
Western Siberia ◽  
13C Nmr Spectroscopy ◽  
Total Carbon ◽  
The Arctic ◽  
Total Carbon Content ◽  
Ambient Temperatures ◽  
Arctic Soils ◽  
Spatial Coverage

Abstract. Arctic soils contain large amounts of organic matter which, globally, exceed the amount of carbon stored in vegetation biomass and in the atmosphere. Recent studies emphasize the potential sensitivity for this soil organic matter (SOM) to be mineralised when faced with increasing ambient temperatures. In order to better refine the predictions about the response of SOM to climate warming, there is a need to increase the spatial coverage of empirical data on SOM quantity and quality in the Arctic area. This study provides, for the first time, a characterisation of SOM from the Gydan Peninsula in the Yamal Region, Western Siberia, Russia. On the one hand, soil humic acids and their humification state were characterised by measuring the elemental composition and diversity of functional groups using solid-state 13C-NMR spectroscopy. Also, the total mineralisable carbon was measured. Our results show that there is a uniformity of SOM characteristics throughout the studied region, as well as within soil profiles. Such in-depth homogeneity, together with a predominance of aliphatic carbon structures, suggests the accumulation in soil of raw and slightly decomposed organic matter. Moreover, results on total mineralisable carbon suggest a high lability of these compounds. The mineralisation rate was found to be independent of SOM quality, and to be mainly explained solely by the total carbon content. Overall, our results provide further evidence on the fundamental role that the soils of Western Siberia may have on regulating the global carbon balance when faced with increasing ambient temperatures.

Accurate continuous observations of carbon dioxide and methane dry mole fractions in the arctic atmosphere near the Dikson settlement, Siberia

2021 ◽  
Author(s):  
Alexey Panov ◽  
Anatoly Prokushkin ◽  
Jošt Lavrič ◽  
Karl Kübler ◽  
Mikhail Korets ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Basic Research ◽  
Local Environment ◽  
The Arctic ◽  
Taimyr Peninsula ◽  
Data Quality Control ◽  
Max Planck ◽  
Frozen Ground ◽  
Gas Measurements ◽  
Arctic Atmosphere

&lt;div&gt; &lt;p&gt;&lt;span&gt;Measurements of the atmospheric sources and sinks of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) and methane (CH&lt;sub&gt;4&lt;/sub&gt;) in the pan-Arctic domain are extremely sparse that limits our knowledge of carbon cycling over this dramatically sensitive environment and making predictions about a fate of carbon conserved in currently frozen ground. Especially critical are the gaps in the arctic latitudes of Siberia, covered by the vast permafrost underlain tundra, where only few continuous atmospheric observation stations are currently operational.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;We present the first two years of accurate continuous observations of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; dry mole fractions at the new atmospheric carbon observation station located near the Dikson settlement (73.33&amp;#176; N, 80.34&amp;#176; E) on the seashore of the western part of the Taimyr Peninsula in Siberia. Data quality control of trace gas measurements is achieved by regular calibrations against WMO-traceable reference gases from pressurized dry air tanks filled at the Max Planck Institute for Biogeochemistry (Jena, Germany). Associated meteorological variables permit evaluation of the climate variability of the local environment and provide a background for screening and interpreting the greenhouse gases (GHG) data records.&amp;#160;&lt;/span&gt;&lt;span&gt;Here we summarize the scientific rationale of the new site, give technical details of the instrumental setup, analyse the local environments and present CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt; and CH&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt; fluctuations in the arctic atmosphere. Along with the temporal variability of GHG&amp;#8217;s, we provide an overview of the angular distribution of detected GHG signals in the region and their input to the atmospheric fluctuations on the measurement site. Observation records deal with the daytime mixed layer and may be considered as representative throughout the vast area (~500&amp;#8211;1000 km), and cover the period from September 2018 to September 2020.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;The &lt;/span&gt;&lt;span&gt;reported study&lt;/span&gt;&lt;span&gt; was funded by Russian Foundation for Basic Research, Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science, project number 20-45-242908, RFBR project &lt;/span&gt;&lt;span&gt;18-05-60203&lt;/span&gt;&lt;span&gt; and &lt;/span&gt;&lt;span&gt;by the Max Planck Society (Germany)&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;

scholarly journals Temporal biomass dynamics of an Arctic plankton bloom in response to increasing levels of atmospheric carbon dioxide

2012 ◽  
Vol 9 (9) ◽  
pp. 12543-12592 ◽  
Author(s):  
K. G. Schulz ◽  
R. G. J. Bellerby ◽  
C. P. D. Brussaard ◽  
J. Büdenbender ◽  
J. Czerny ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Organic Matter ◽  
Trophic Levels ◽  
The Arctic ◽  
Second Phase ◽  
Chl A ◽  
Co2 Effects ◽  
Autotrophic Biomass ◽  
Plankton Bloom ◽  
Standing Stocks

Abstract. Ocean acidification and carbonation, driven by anthropogenic emissions of carbon dioxide (CO2), have been shown to affect a variety of marine organisms and are likely to change ecosystem functioning. High latitudes, especially the Arctic, will be the first to encounter profound changes in carbonate chemistry speciation at a large scale, namely the under-saturation of surface waters with respect to aragonite, a calcium carbonate polymorph produced by several organisms in this region. During a CO2 perturbation study in 2010, in the framework of the EU-funded project EPOCA, the temporal dynamics of a plankton bloom was followed in nine mesocosms, manipulated for CO2 levels ranging initially from about 185 to 1420 μatm. Dissolved inorganic nutrients were added halfway through the experiment. Autotrophic biomass, as identified by chlorophyll a standing stocks (Chl a), peaked three times in all mesocosms. However, while absolute Chl a concentrations were similar in all mesocosms during the first phase of the experiment, higher autotrophic biomass was measured at high in comparison to low CO2 during the second phase, right after dissolved inorganic nutrient addition. This trend then reversed in the third phase. There were several statistically significant CO2 effects on a variety of parameters measured in certain phases, such as nutrient utilization, standing stocks of particulate organic matter, and phytoplankton species composition. Interestingly, CO2 effects developed slowly but steadily, becoming more and more statistically significant with time. The observed CO2 related shifts in nutrient flow into different phytoplankton groups (mainly diatoms, dinoflagellates, prasinophytes and haptophytes) could have consequences for future organic matter flow to higher trophic levels and export production, with consequences for ecosystem productivity and atmospheric CO2.

scholarly journals Modern Landfills as Potential Feed Back Processes to Counteract Global Warming

2017 ◽  
pp. 780-787
Author(s):  
Torleif Bramryd ◽  
Michael Johansson
Keyword(s):  
Carbon Dioxide ◽  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Dioxide Emissions ◽  
Landfill Gas ◽  
Mineral Soil ◽  
Motor Fuel ◽  
Total Carbon ◽  
Water Evaporation ◽  
Total Carbon Content

Provided that produced biogas is effectively collected, landfills are important sinks for organic carbon compensating for emissions of CO2 from burning of fossil fuels. Sequestrating of long-lived organic carbon in the landfill itself is the most pronounced factor, but also other processes during landfill management will increase the capture and binding of CO2.. Compost produced in connection to the landfills and applied as soil improvement, is another important sink for organic carbon.The landfills in the World have been estimated to accumulate around 100 x 106 metric tons of C. Normally about 25-40 percent of the total carbon content in the waste can be converted into biogas in traditional landfills. During landfilling most of the organic carbon in fossil derived products, like plastics, synthetic rubber, textiles and other synthetic materials, As these products take part in the methane gas production, the landfill gas (biogas) can be regarded as a true biofuel. In contrast to incineration, high moisture content in the waste will not decrease the yield of energy per ton of waste. In a reactor landfill treating approximately 100 000 tons of waste per year, a longlived organic fraction corresponding to about 45 000 metric tons of carbon dioxide is longterm accumulated each year. This compensates for the annual carbon dioxide emissions from about 15 000 – 20 000 cars, provided that each one runs 15 000 km per year with fossil fuel. The technique for effective collection of landfill gas, and new techniques to upgrade and liquefy the biogas, have decreased the risk for emissions to the atmosphere. Modern bioreactor landfills have been estimated to have less than 10% diffuse biogas emissions to the atmosphere. Also in Sweden (Helsingborg), plants are built to convert landfill gas to upgraded, liquefied motor fuel. This will lead to strongly reduced diffuse emissions of landfill gas to the atmosphere. The utilization of leachates as forest fertilizer results in an improved biomass production and increased accumulation of soil organic matter. Increased tree and field layer productivity also means that the potential for water evaporation (eg. evapotranspiration) increase, reducing the costs for waste-water treatment or the risk for diffuse ground water pollution. Also in the mineral soil, increased long-lived fractions of humus normally are found. This should be added to the carbon accumulating effect of the landfill itself, where long-lived organic matter, mainly derived from lignin and from fossil fractions as plastics and synthetic textiles is long-term accumulated. In this respect the landfill system has similar effects compared to natural peatlands and lake and sea sediments, Ifproduced biogas is collected effectively, the landfill thus can be an important factor to counteract the “green-house effect” and climate change.

Soil nitrogen mineralisation and organic matter composition revealed by 13C NMR spectroscopy under repeated prescribed burning in eucalypt forests of south-east Queensland

Soil Research ◽  
1999 ◽  
Vol 37 (1) ◽  
pp. 123 ◽  
Author(s):  
D. F. Guinto ◽  
Z. H. Xu ◽  
P. G. Saffigna ◽  
A. P. N. House ◽  
M. C. S. Perera
Keyword(s):  
Organic Matter ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Prescribed Burning ◽  
13C Nmr Spectroscopy ◽  
High Ratio ◽  
N Mineralisation ◽  
Total N ◽  
Organic C ◽  
Organic Matter Composition

The effects of burning on in situ extractable nitrogen (NH+4-N+NO-3-N) and net Nmineralisation following scheduled fuel reduction burns in repeatedly burnt dry and wet sclerophyll forest sites in south-east Queensland were assessed. In addition, soil organic matter composition in the wet sclerophyll site was assessed by 13C NMR spectroscopy. The results showed that at the dry sclerophyll site, extractable N and net N mineralisation for 1 year were largely unaffected by burning, while at the wet sclerophyll site, these parameters decreased. 13C NMR analysis of soil samples from the wet sclerophyll site revealed that there was a significant reduction in the proportion of O-alkyl (alkoxy/carbohydrate) C with increasing burning frequency. Statistically significant effects on the other chemical shift regions were not detected. The ratio of alkyl C to O-alkyl C, a proposed index of organic matter decomposition, increased with increasing burning frequency. A high ratio of alkyl C to O-alkyl C suggests low amounts of carbohydrates relative to waxes and cutins, which could in turn lead to slower mineralisation. The findings are in accord with this hypothesis. There were significant linear relationships between cumulative N mineralisation for 1 year and the proportions of alkyl C and O-alkyl C, and the ratio of alkyl C/O-alkyl C. Thus, in addition to reductions in substrate quantity (low organic C and total N for burnt soils), there was also an alteration of substrate quality as revealed by 13C NMR spectroscopy which is reflected in low N mineralisation.

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