Generation,sink, and emission of greenhouse gases by urban soils at different stages of the floodplain development in Moscow     

Lebed-Sharlevich  Yana  Kulachkova  Svetlana  Mozharova  Nadezhda 《Journal of Soils and Sediments》2019,19(8):3204-3216

Purpose

The purpose of this research was to study the generation, sink, and emission of greenhouse gases by soils on technogenic parent materials, created at different stages of the Moskva River floodplain development (1—construction and 2—landscaping of residential areas).

Materials and methods

Field surveys revealed the spatial trends of concentration and emission of the greenhouse gases in following groups of soils: Retisols (RT-ab-ct) and Fluvisols (FL-hu, FL-hi.gl) before land engineering preparation for the construction, Urbic Technosols Transportic (TC-ub-ar.tn and TC-ub-hu.tn) at stage 1 and Urbic Technosols Folic (TC-ub-fo) at stage 2. CO₂ and CH₄ concentration in soils and their emission were determined using subsurface soil air equilibration tubes and the closed chamber method, respectively. Bacterial methane generation rate (MGR) and methane oxidation rate (MOR) were measured by kinetic methods.

Results and discussion

In natural soils MOR is caused only by intra-aggregate methanogenesis. The imbalance of methane generation and oxidation was observed in FL-hi.gl. It caused CH₄ accumulation in the profile (7.5 ppm) and its emission to the atmosphere (0.11 mg CH₄ m^?2 h^?1). RT-ab-ct acted as the sink of atmospheric methane. CO₂ emission was 265.1?±?24.0 and 151.9?±?37.2 mg CO₂ m^?2 h^?1 from RT-ab-ct and FL-hi.gl, respectively. In Technosols CH₄ concentration was predominantly low (median was 2.7, 2.9, and 3.0 ppm, in TC-ub-ar.tn, TC-ub-hu.tn, and TC-ub-fo, respectively), but due to the occurrence of peat sediments under technogenic material, it increased to 1–2%. Methane emission was not observed due to functioning of biogeochemical barriers with high MOR. In TC-ub-ar.tn and TC-ub-hu.tn, the barriers were formed at 60-cm depth. In TC-ub-fo, the system of barriers was formed in Folic and Technic horizons (at 10- and 60-cm depth). CO₂ emission was 2 times lower from TC-ub-ar.tn and TC-ub-hu.tn and 1.5 times higher from TC-ub-fo than from natural soils.

Conclusions

Greenhouse gas generation, sink, and emission by natural soils and Technosols in floodplain were estimated. CO₂ and CH₄ content in Technosols varied depending on the properties of parent materials. Technosols at stage 1 did not emit CH₄ due to formation of biogeochemical barriers—soil layers of high CH₄ utilization rates. Urbic Technosols (Folic) at stage 2 performed as a source of significant CO₂ emission.

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Biofiltration of methane by soil and soil-like constructions and specifics of their functioning     

O. V. Lisovitskaya  Ya. I. Lebed-Sharlevich  N. V. Mozharova  S. A. Kulachkova  M. V. Gorlenko 《Moscow University Soil Science Bulletin》2013,68(3):135-141

Methane consumption in constructions is driven by its intense biofiltration which differs by seasons according to the general specifics of the functioning of methanotrophs. Three stages of methane biofiltration were identified—adaptation, optimum, and stress. It was established that methane biofiltration in soil construction is 1.5–2.0 times higher than in soil-like constructions. The biofiltration process under intense methane inflow leads to filtrate acidity increase; the Eh value drops in the summer period in constructions and grows during the winter season; a significant increase in microbial community stability is observed.  相似文献