Bacterial and archaeal compositions and influencing factors in soils under different submergence time in a mercury-sensitive reservoir
Introduction
Reservoirs are different from other aquatic ecosystem in that the water level changes periodically due to artificial regulation, and a certain area of water-level-fluctuating zone (WLFZ) is formed in the drying period. Since 1980s, it has been found in North America and Europe that the concentrations of methylmercury (MeHg) in plankton, insects and fish in many new reservoirs increased significantly due to the construction of reservoirs (Abernathy and Cumbie, 1977; Lodenius et al., 1983). Therefore, new reservoirs are found to be conducive to the activation and methylation of mercury (Hg) and are considered to be a typical “Hg sensitive ecosystem” (Feng et al., 2009a; Xiang et al., 2014, 2018). The increase of MeHg caused by reservoir construction is called “reservoir effect” of Hg (Feng, 2011). Extensive research on the biogeochemical cycle of Hg in reservoirs were conducted worldwide (Eckley et al., 2017; Feng et al., 2009a, 2009b; Gray and Hines, 2009; Hecky et al., 1991; Jackson, 1988; Wasik et al., 2015). Among millions of reservoirs constructed worldwide, Three Gorges Reservoir (TGR) seems to be by far the largest annual regulation one as a world-renowned super-large project. Since its completion, its water level has been periodically adjusted and controlled up to 175 m per year, resulting in the formation of WLFZ of 30 m in vertical height and 350 km2 in area. The periodic and critically considerable fluctuation makes TGR possess conspicuous “reservoir effect” of Hg from other old reservoirs, which means TGR possesses the characteristics of Hg of new reservoirs every year (Zhao et al., 2015). More importantly, previous research has revealed that soils inundated by water for different periods of time in the WLFZ, TGR had disparate characteristics to Hg and MeHg (Du et al., 2017; He, 2013; Xiang et al., 2014, 2018). Therefore, the reservoir effect of Hg in TGR has raised great concern in the past years. In addition, the biogeochemical circle of Hg is a complex process and is confirmed to be affected by a wide variety of environmental factors, including microbial species and structures, concentrations of Hg2+ and MeHg, cation exchange capacity (CEC), base saturation (BS), organic matter (OM), pH values, Fe2+, NH4+, SO42−, etc. (Frohne et al., 2012; Merritt and Amirbahman, 2009; Ullrich et al., 2001). Currently, microbial species being confirmed to possess essential roles in biogeochemical cycle of Hg primarily include sulfate reducing bacteria (SRB), iron reducing bacteria (IRB) and methanogens, distributed mainly in δ-Proteobacteria (Parks et al., 2013; Ranchoupeyruse et al., 2009), Clostridia (Gilmour et al., 2013), and Methanobacteria (Gilmour et al., 2013, 2018; Yu et al., 2013; Podar et al., 2015). However, it is still not known that what kind of microorganisms are dominantly distributed in different soil types of the WLFZ of TGR, and how these microbial species are affected by various biogeochemical factors in reservoir ecosystem under artificial interference. Therefore, the main objective of this study is to analyze and compare dominant microorganisms in soils under different submergence time and how they are affected by biogeochemical factors, especially Hg and MeHg concentrations, in the biggest reservoirs worldwide so far.
Section snippets
Study area
Chongqing is located in the upper reaches of Yangtze River in the eastern part of Sichuan Basin, southwest China. The tested soil and sediment samples were collected from the WLFZ of Xinzheng Village, Shibao County (S for short), Zhong County, Chongqing (Fig. 1) (E108°7′41"; N30°25′40″). Previous research had demonstrated that SRB-related Hg-methylators were of higher α-diversity and abundance in Shibao County among several sites researched (Du et al., 2017), so it was selected in this research
Species richness, evenness and diversities
A total of 12 samples were sequenced on PE300 platform. The number of reads ranged from 32041 to 62665, with average length of 447.9 bp for archaea, while the number of reads for bacterial 16S rRNA sequencing ranged from 33060 to 58606, with average length of 439.7 bp. Bacteria and archaea 16S rRNA amplicon sequencing yielded 3786 and 489 OTUs based on the minimum sample sequence, which matched to 734 and 59 known genera respectively. Rarefaction curves showing relationship between the number
Conclusion
Bacterial and archaeal richness, α-diversities and compositions, as well as affecting variables among soils and sediments under different submergence time, namely inundated, semi-inundated soil and non-inundated soils, as well as sediment in a Hg-sensitive reservoir, TGR were investigated and compared based on 16S rRNA amplicon high throughput sequencing. As expected, the sediment being deeply-submerged in water throughout the whole year had significantly higher bacterial and archaeal richness
Notes
The authors declare no competing financial interest.
CRediT authorship contribution statement
Hongxia Du: Formal analysis, Writing - original draft. Tao Sun: Data curation, Methodology. Dingyong Wang: Supervision, Writing - review & editing. Ma Ming: Conceptualization, Methodology, Data curation.
Acknowledgements
This work was supported by the National Natural Science Foundation of China (No. 41603098 & 41877382), Fundamental Research Funds for the Central Universities (No. XDJK2018B043 & XDJK2019B073), Natural Science Foundation of Chongqing (No. cstc2017jcyjAX0250) and Natural Technical Innovation and Application Demonstration Project of Chongqing (No. cstc2018jscx-msybX0080).
References (64)
- et al.
Soil suppressiveness and its relations with the microbial community in a Brazilian subtropical agroecosystem under different management systems
Soil Biol. Biochem.
(2016) - et al.
Water-level fluctuations influence sediment porewater chemistry and methylmercury production in a flood-control reservoir
Environ. Pollut.
(2017) - et al.
Mercury mass balance study in wujiangdu and dongfeng reservoirs, guizhou, China
Environ. Pollut.
(2009) - et al.
Geochemical processes of mercury in wujiangdu and dongfeng reservoirs, guizhou, China
Environ. Pollut.
(2009) - et al.
Electron accepting capacity of dissolved and particulate organic matter control CO2 and CH4 formation in peat soils
Geochem. Cosmochim. Acta
(2019) - et al.
Carbon, cations and CEC: interactions and effects on microbial activity in peat
Geoderma
(2009) - et al.
Biogeochemical mercury methylation influenced by reservoir eutrophication, salmon falls creek reservoir, Idaho, USA
Chem. Geol.
(2009) - et al.
Physico-chemical properties and microbial responses in biochar-amended soils: mechanisms and future directions
Agric. Ecosyst. Environ.
(2015) - et al.
Influence of dissolved organic matter (DOM) characteristics on dissolved mercury (Hg) species composition in sediment porewater of lakes from southwest china
Water Res.
(2018) - et al.
Long-term effects of organic and synthetic soil fertility amendments on soil microbial communities and the development of southern blight
Soil Biol. Biochem.
(2007)
Evolution of microbial community along with increasing solid concentration during high-solids anaerobic digestion of sewage sludge
Bioresource technol
Characteristics of archaea and bacteria in rice rhizosphere along a mercury gradient
Sci. Total Environ.
Mercury methylation dynamics in estuarine and coastal marine environments-a critical review
Earth Sci. Rev.
Environmental contamination of mercury from Hg-mining areas in Wuchuan, northeastern Guizhou, China
Environ. Pollut.
Soil pH drives the spatial distribution of bacterial communities along elevation on Changbai Mountain
Soil Biol. Biochem.
A review of studies on the biogeochemical behaviors of mercury in the three gorges reservoir, China
Bull. Environ. Contam. Toxicol.
Water level fluctuations influence microbial communities and mercury methylation in soils in the Three Gorges Reservoir, China
J. Environ. Sci.
Effect of biochar additions to soil on nitrogen leaching, microbial biomass and bacterial community structure
Eur. J. Soil Biol.
Mercury accumulation by largemouth bass (Micropterus-Salmoides) in recently impounded reservoirs
Bull. Environ. Contam. Toxicol.
Chemical and biological gradients along the damma glacier soil chronosequence, Switzerland
Vadose Zone J.
Support for an anaerobic sulfur cycle in two Canadian peatland soils
J. Geophys. Res. Biogeosci.
Geochemistry and environmental threats of soils surrounding an abandoned mercury mine
Environ. Sci. Pollut. Res.
Phylogenetic diversity and ecological pattern of ammonia-oxidizing archaea in the surface sediments of the western pacific
Microb. Ecol.
Sediment microbial diversity of three deep-sea hydrothermal vents southwest of the azores
Microb. Ecol.
Soil bacterial diversity in the Arctic is not fundamentally different from that found in other biomes
Environ. Microbiol.
Surface exposure to sunlight stimulates CO2 release from permafrost soil carbon in the Arctic
Proc. Natl. Acad. Sci.
Mercury-methylating genes dsrB and hgcA in soils/sediments of the Three Gorges Reservoir
Environ. Sci. Pollut. Res.
Soil microbial community composition and environmental controls in northern temperate steppe of China
Acta Sci. Nauralium Univ. Pekin.
A review on mercury biogeochemical cycling in reservoirs
Environ. Prot. Technol.
Toward an ecological classification of soil bacteria
Ecology
Second-generation environmental sequencing unmasks marine metazoan biodiversity
Nat. Commun.
Biogeochemical factors affecting mercury methylation rate in two contaminated floodplain soils
Biogeosciences
Cited by (6)
Mechanisms and biological effects of organic amendments on mercury speciation in soil–rice systems: A review
2023, Ecotoxicology and Environmental SafetyMicrobial diversity alteration reveals biomarkers of contamination in soil-river-lake continuum
2022, Journal of Hazardous MaterialsCitation Excerpt :Actibacter was found significantly abundant in aquatic sediments, Thiobacillus in the river and soil compartments (LEfSe, p < 0.05), while LEfSe revealed no specific habitat for Anaerolinea (Fig. 4). Interestingly, Anaerolinea has been detected in mercury contaminated soil/water transition zone (Du et al., 2020), being more abundant in sediment than in soil. It is likely that this genus is well adapted to the variation of environmental parameters as that occurring in mixing zone such as soil-river-lake continuum.