Features of the organic matter transformation in the active layer of permafrost in the Bureya river basin
L. M. KONDRATYEVA1, D. V. ANDREEVA1, Z. N. LITVINENKO1, V. P. SHESTERKIN1, E. M. GOLUBEVA2
1Khabarovsk Federal Research Center Institute of the Water and Ecology Problems FEB RAS
2Yu. A. Kosygin Institute of Techtonics and Geophysics FEB RAS
Keywords: water composition, permafrost, active layer, microbial complexes, humic substances
Abstract
Climate change contributes to increased attention on factors determined the dynamics of biogeochemical processes in active layer of biosphere (seasonally thawing/freezing soils) on the border with permafrost. There are geological, geomorphic, weather conditions associated with atmospheric precipitations, which determine the differences in the segregation and depth of permafrost thawing in different regions. Research area is Bureya River Basin with intermittent distribution of permafrost within unique landscape units - marshes. It is formed in swampy, poorly drained areas, where the active soil layer is in contact with permafrost, and has a direct impact on the quality of surface waters. The results of the study include the information about composition of water in different order tributaries by hydrochemical parameters; spectral characteristics of soluble organic matters (OM) in water extracts of soils from different horizons of the active layer; assessment of the activity of microbial complexes in relation to humic substances depending on the permafrost depth. The heterogeneity of landscapes is an important factor influencing the transport of OM into watercourses. Microbial complexes of the active layer involved in the transformation of humic substances played a decisive role in changing the composition of soluble OM. It was experimentally shown that temperature influences the qualitative composition of humic metabolism products, including the ratio between aliphatic, aromatic fragments and chromophore groups responsible for the color of natural waters.
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