TY - JOUR

T1 - Experimental transformation of organic matter by the microbial community from the bottom sediments of Akademichesky Ridge (Lake Baikal)

AU - Pavlova, O. N.

AU - Bukin, S. V.

AU - Kostyreva, E.

AU - Moskvin, V. I.

AU - Manakov, A. Yu

AU - Morozov, I. V.

AU - Galachyants, Yu P.

AU - Khabuev, A. V.

AU - Zemskaya, T. I.

N1 - Publisher Copyright: © 2019, V.S. Sobolev IGM, Siberian Branch of the RAS. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2019/8

Y1 - 2019/8

N2 - We discuss the results of a model experiment on cultivation of the microbial community from the area of the Khoboy mud volcano (Akademichesky Ridge) conducted under conditions typical of the hydrocarbon generation zone (80 °C, 5 MPa). The cultivation under conditions of biomass enrichment with the Baikal diatom Synedra acus changed the composition of organic matter. The transformation degree of organic matter in the sediment after the experiment was 16%, whereas the concentration of phenanthrenes relative to methyl-substituted homologues, including retene, decreased, and the concentration of dibenzothiophenes relative to normal alkanes increased. We have identified tri- and monoaromatic steroids, including 17-dismethyl, 23-methyl monoaromatic steroids C27. An increase in the concentration of tri- and monoaromatic steroids in the sediments after the experiment might indicate that the biomass of the Baikal diatom S. acus was destructed, which led to an increase in the steroid concentration. In the control (sterile) sediment, we detected no changes in the composition of organic matter. Representatives of various taxa capable of surviving in anaerobic thermophilic conditions have been identified in the microbial community by molecular genetic methods. Their presence in the surface sediments might be due to the inflow of deep-seated mineralized fluids and breccia from deep-seated sedimentary rocks.

AB - We discuss the results of a model experiment on cultivation of the microbial community from the area of the Khoboy mud volcano (Akademichesky Ridge) conducted under conditions typical of the hydrocarbon generation zone (80 °C, 5 MPa). The cultivation under conditions of biomass enrichment with the Baikal diatom Synedra acus changed the composition of organic matter. The transformation degree of organic matter in the sediment after the experiment was 16%, whereas the concentration of phenanthrenes relative to methyl-substituted homologues, including retene, decreased, and the concentration of dibenzothiophenes relative to normal alkanes increased. We have identified tri- and monoaromatic steroids, including 17-dismethyl, 23-methyl monoaromatic steroids C27. An increase in the concentration of tri- and monoaromatic steroids in the sediments after the experiment might indicate that the biomass of the Baikal diatom S. acus was destructed, which led to an increase in the steroid concentration. In the control (sterile) sediment, we detected no changes in the composition of organic matter. Representatives of various taxa capable of surviving in anaerobic thermophilic conditions have been identified in the microbial community by molecular genetic methods. Their presence in the surface sediments might be due to the inflow of deep-seated mineralized fluids and breccia from deep-seated sedimentary rocks.

KW - Deep biosphere

KW - Lake Baikal

KW - Microbial community

KW - Temperature and pressure conditions

KW - Transformation of organic matter

UR - http://www.scopus.com/inward/record.url?scp=85079492990&partnerID=8YFLogxK

U2 - 10.15372/RGG2019099

DO - 10.15372/RGG2019099

M3 - Article

VL - 60

SP - 926

EP - 937

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 8

ER -