Biophile elements, mineral composition and microbiological peculiarities of soils of halomorphic oases of the intracontinental endorheic Uldza-Torey lake basin
L. L. UBUGUNOV1,2, V. I. UBUGUNOVA1, T. A. AYUSHINA1, TS. N. NASATUEVA1, A. S. SYRENZHAPOVA2, E. I. LASTOCHKIN3, A. D. ZHAMBALOVA1, O. V. VISHNYAKOVA1, E. YU. ABIDUEVA1
1Institute of General and Experimental Biology of SB RAS, Ulan-Ude, Russia
2Buryat State Agricultural Academy named after V. R. Filippov, Ulan-Ude, Russia
3Institute of Geology named after N. L. Dobretsov of SB RAS, Ulan-Ude, Russia
Keywords: biophilic macro- and microelements, halomorphic soils of oases, Uldza-Torey endorheic lake basin, biotic and abiotic components of ecosystems
Abstract
The content of biophilic elements in soils and minerals of coastal depressions of highly mineralized chloride lakes of the Uldza-Torey endorheic basin (Russia, Dauria) and the microbiota involved in the cycles of these elements were studied comprehensively for the first time. Obtained data on the gross content and mobile forms of biophilic macro- (N, P, K, Na, Ca, Mg, Fe, S) and microelements (Mn, Zn, Cu, Cr, Ni, Co) in soils of the local “node” of biota concentration of the Uldza-Torey basin revealed differences in the geosphere-biosphere interactions of biotic and abiotic components in quasi-gley solonchaks, saline humus-gley and saline light-humus soils. High significance of halomorphic soils for preserving the biodiversity of steppe territories (Dauria, Transbaikalia) has been established. Maximal concentrations of the total content of biophilic elements and mobile forms of nitrogen, sulfur, calcium, sodium, manganese, and magnesium were revealed within the Sg, ca horizon of the quasi-gley solonchak. This layer is characterized by the highest index of microbial diversity, a significant proportion of taxa participating in the cycles of biophilic elements, and formation of new minerals with wide variations of silicon, aluminum, and sodium. The underlying horizons of solonchak (CQs) are enriched in sodium, magnesium, and sulfur under the impact of sulfate-chloride-sodium ground waters. Calcite, calcium amphiboles, and monocyte predominate in their mineralogical composition. Enrichment of solonchaks with mobile forms of biophilic elements, presence of various minerals containing Na, Ca, Mg, Fe, and rare earth elements (Ce, La, Nd, Sm, Th) confirm both the sodium and rare-earth hypotheses of animal lithophagy. A significant deficit of most gross and mobile forms of biophilic elements, decrease in microbial diversity, and typical for acidic rocks minerals, rarely basites, were noted in the upper horizons of humus-gley saline and light-humus saline soils. In the lower layers formed by paleohydromorphic lake sediments, oxides with a low proportion of chlorine, sulfur and sodium (8-15 %), and enrichment in easily soluble salts and mobile forms of sodium and sulfur were revealed. The content of other biophilic elements was estimated as low and very low.
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