Distribution of functional microorganisms and its significance for iron, sulphur, and nitrogen cycles in reservoir sediments

• Published in: Acta geochimica Vol. 40; no. 6; pp. 961 - 972
• Main Authors: Bai, Shuang, Yang, Meilin, Chen, Zheng, Yang, Ming, Ma, Jing, Chen, Xue-Ping, Wang, Fushun
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.12.2021; Springer Nature B.V; School of Environmental and Chemical Engineering,Shanghai University,99 Shangda Road,BaoShan District,Shanghai 200444,China%Department of Health and Environmental Sciences,Xi'an Jiaotong-Liverpool University,Suzhou 215123,Jiangsu,China
• Subjects: Aerobic respiration; Biodegradation; Biogeochemical cycle; Biogeochemical cycles; Contaminants; Denitrification; Distribution; Earth and Environmental Science; Earth Sciences; Electrons; Geochemistry; Iron; Microorganisms; Nitrogen; Nutrients; Original Article; Oxidoreductions; Pore water; Reservoirs; Respiration; Sediment; Sediments; Stratification; Sulfate reduction; Sulfates; Sulfur; Sulphate reduction; Sulphides; Sulphur; Vertical distribution; Redox; Denitrification; Geochemical cycle; Microbial community; Reservoir sediment
• DOI: 10.1007/s11631-021-00492-0
• ISSN: 2096-0956

The biogeochemical cycles of sulphur (S), iron (Fe) and nitrogen (N) elements play a key role in the reservoir ecosystem. However, the spatial positioning and interrelationship of S, Fe and N cycles in the reservoir sediment profile have not been explored to a greater extent. Here, we measure the gradients of Fe 2+ , SO 4 2− , NO 3 − , NH 4 + , DOC, TC and TN in the pore water of the sediment, and combining the vertical distribution of the functional microorganisms involved in S, Fe and N cyclings in the sediments to determine the redox stratification in the sediment. It is found that the geochemical gradient of S, Fe and N of the reservoir sedimentary column is mainly defined by the redox process involved in the related functional microorganisms. According to the type of electron acceptor, the sediment profile is divided into 3 redox intervals, namely aerobic respiration (0–10 cm), denitrification/iron reduction (10–28 cm) and sulfate reduction (28–32 cm). In the aerobic respiration zone, NH 4 + is oxidized by aerobic AOB to NO 3 − (0–5 cm), and Fe 2+ is oxidized by microaerobic FeRB to Fe 3+ (3–10 cm). In the denitrification/iron reduction zone, Acinetobacter and Pseudomonas , as the dominant NRB genera, may use nitrate as an electron acceptor to oxidize Fe 2+ (11–16 cm). The dominant genera in SOB, such as Sulfururvum , Thiobacillus and Thioalkalispira , may use nitrate as an electron acceptor to oxidize sulfide, leading to SO 4 2− accumulation (14–24 cm). In the sulfate reduction zone, SO 4 2− is reduced by SRB. This study found that functional microorganisms forming comprehensive local ecological structures to adapt to changing geochemical conditions, and which would be potentially important for the degradation and preservation of C and the fate of many nutrients and contaminants in reservoirs.