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Mo J, Song Z, Che Y, Li J, Liu T, Feng J, Wang Z, Rong J, Gu S. Effects of aeolian deposition on soil properties and microbial carbon metabolism function in farmland of Songnen Plain, China. Sci Rep 2024; 14:14791. [PMID: 38926449 DOI: 10.1038/s41598-024-65578-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 06/21/2024] [Indexed: 06/28/2024] Open
Abstract
The effects of wind erosion, one of the crucial causes of soil desertification in the world, on the terrestrial ecosystem are well known. However, ecosystem responses regarding soil microbial carbon metabolism to sand deposition caused by wind erosion, a crucial driver of biogeochemical cycles, remain largely unclear. In this study, we collected soil samples from typical aeolian deposition farmland in the Songnen Plain of China to evaluate the effects of sand deposition on soil properties, microbial communities, and carbon metabolism function. We also determined the reads number of carbon metabolism-related genes by high-throughput sequencing technologies and evaluated the association between sand deposition and them. The results showed that long-term sand deposition resulted in soil infertile, roughness, and dryness. The impacts of sand deposition on topsoil were more severe than on deep soil. The diversity of soil microbial communities was significantly reduced due to sand deposition. The relative abundances of Nitrobacteraceae, Burkholderiaceae, and Rhodanobacteraceae belonging to α-Proteobacteria significantly decreased, while the relative abundances of Streptomycetaceae and Geodermatophilaceae belonging to Actinobacteria increased. The results of the metagenomic analysis showed that the gene abundances of carbohydrate metabolism and carbohydrate-activity enzyme (GH and CBM) significantly decreased with the increase of sand deposition amount. The changes in soil microbial community structure and carbon metabolism decreased soil carbon emissions and carbon cycling in aeolian deposition farmland, which may be the essential reasons for land degradation in aeolian deposition farmland.
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Affiliation(s)
- Jixian Mo
- College of Resources and Environment, Northeast Agricultural University, Harbin, 150030, China
- College of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, 161006, China
| | - Ziwei Song
- College of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, 161006, China
| | - Yanjing Che
- College of Resources and Environment, Northeast Agricultural University, Harbin, 150030, China
| | - Jie Li
- College of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, 161006, China
| | - Tianyi Liu
- College of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, 161006, China
| | - Jingyi Feng
- College of Resources and Environment, Northeast Agricultural University, Harbin, 150030, China
| | - Ziying Wang
- College of Resources and Environment, Northeast Agricultural University, Harbin, 150030, China
| | - Jiandong Rong
- Qiqihar Experimental Station, Heilongjiang Province Hydraulic Research Institute, Qiqihar, 161006, China
| | - Siyu Gu
- College of Resources and Environment, Northeast Agricultural University, Harbin, 150030, China.
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Liao H, Hao X, Li Y, Ma S, Gao S, Cai P, Chen W, Huang Q. Protists regulate microbially mediated organic carbon turnover in soil aggregates. GLOBAL CHANGE BIOLOGY 2024; 30:e17102. [PMID: 38273557 DOI: 10.1111/gcb.17102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 11/05/2023] [Accepted: 11/09/2023] [Indexed: 01/27/2024]
Abstract
Soil protists, the major predator of bacteria and fungi, shape the taxonomic and functional structure of soil microbiome via trophic regulation. However, how trophic interactions between protists and their prey influence microbially mediated soil organic carbon turnover remains largely unknown. Here, we investigated the protistan communities and microbial trophic interactions across different aggregates-size fractions in agricultural soil with long-term fertilization regimes. Our results showed that aggregate sizes significantly influenced the protistan community and microbial hierarchical interactions. Bacterivores were the predominant protistan functional group and were more abundant in macroaggregates and silt + clay than in microaggregates, while omnivores showed an opposite distribution pattern. Furthermore, partial least square path modeling revealed positive impacts of omnivores on the C-decomposition genes and soil organic matter (SOM) contents, while bacterivores displayed negative impacts. Microbial trophic interactions were intensive in macroaggregates and silt + clay but were restricted in microaggregates, as indicated by the intensity of protistan-bacterial associations and network complexity and connectivity. Cercozoan taxa were consistently identified as the keystone species in SOM degradation-related ecological clusters in macroaggregates and silt + clay, indicating the critical roles of protists in SOM degradation by regulating bacterial and fungal taxa. Chemical fertilization had a positive effect on soil C sequestration through suppressing SOM degradation-related ecological clusters in macroaggregate and silt + clay. Conversely, the associations between the trophic interactions and SOM contents were decoupled in microaggregates, suggesting limited microbial contributions to SOM turnovers. Our study demonstrates the importance of protists-driven trophic interactions on soil C cycling in agricultural ecosystems.
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Affiliation(s)
- Hao Liao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, China
| | - Xiuli Hao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, China
| | - Yiting Li
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Silin Ma
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, China
| | - Shenghan Gao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, China
| | - Peng Cai
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, China
| | - Wenli Chen
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Qiaoyun Huang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, China
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Wuhan, China
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Yang J, He J, Jia L, Gu H. Integrating metagenomics and metabolomics to study the response of microbiota in black soil degradation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:165486. [PMID: 37442461 DOI: 10.1016/j.scitotenv.2023.165486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/10/2023] [Accepted: 07/10/2023] [Indexed: 07/15/2023]
Abstract
As the largest commercial food production base and ecological security barrier, land degradation in black soil areas seriously threatens the global food supply and natural ecosystems. Therefore, determining the response of soil microbiota is crucial to restoring degraded soils. This study combined metagenomics and metabolomics to investigate the effect of different degrees of soil degradation on microbial community composition and metabolic function in black soils. It was found that alpha diversity in degraded soils (Shannon: 22.3) was higher than in nondegraded soil (ND) (Shannon: 21.8), and the degree of degradation significantly altered the structure and composition of soil microbial communities. The results of LEfSe analysis obtained 9 (ND), 7 (lightly degraded, LD), 10 (moderately degraded, MD), and 1 (severely degraded, SD) biomarkers in four samples. Bradyrhizobium, Sphingomonas, and Ramlibacter were significantly affected by soil degradation and can be considered biomarkers of ND, MD, and SD, respectively. Soil nutrient and enzyme activities decreased significantly with increasing black soil degradation, soil organic matter (SOM) content decreased from 11.12 % to 1.97 %, and Sucrase decreased from 23.53 to 6.59 mg/g/d. In addition, C was the critical driver affecting microbial community structure, contributing 61.2 % to differences in microbial community distribution, and microbial altering relative abundance which participle in the carbon cycle to respond to soil degradation. Metabolomic analyses indicated that soil degradation significantly modified the soil metabolite spectrum, and the metabolic functions of most microorganisms responding to soil degradation were adversely affected. The combined multi-omics analysis further indicated that biomarkers dominate in accumulating metabolites. These findings confirmed that due to their role in the composition and functioning of these degraded soils, these biomarkers could be employed in strategies for managing and restoring degraded black soils.
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Affiliation(s)
- Jia Yang
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Jianhu He
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Lin Jia
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Huiyan Gu
- School of Forestry, Northeast Forestry University, Harbin 150040, China.
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Cheng Y, Zhou L, Liang T, Man J, Wang Y, Li Y, Chen H, Zhang T. Deciphering Rhizosphere Microbiome Assembly of Castanea henryi in Plantation and Natural Forest. Microorganisms 2021; 10:microorganisms10010042. [PMID: 35056492 PMCID: PMC8779262 DOI: 10.3390/microorganisms10010042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/26/2022] Open
Abstract
Based on the importance and sensitivity of microbial communities to changes in the forest ecosystem, soil microorganisms can be used to indicate the health of the forest system. The metagenome sequencing was used to analyze the changes of microbial communities between natural and plantation Castanea henryi forests for understanding the effect of forest types on soil microbial communities. Our result showed the soil microbial diversity and richness were higher in the natural forests than in the plantation. Proteobacteria, Actinobacteria, and Acidobacteria are the dominant categories in the C. henryi rhizosphere, and Proteobacteria and Actinobacteria were significantly enriched in the natural forest while Acidobacteria was significantly enriched in the plantation. Meanwhile, the functional gene diversity and the abundance of functions in the natural forest were higher than that of the plantation. Furthermore, we found that the microbial network in the natural forests had more complex than in the plantation. We also emphasized the low-abundance taxa may play an important role in the network structure. These results clearly showed that microbial communities, in response to different forest types, provide valuable information to manipulate microbiomes to improve soil conditions of plantation.
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Affiliation(s)
- Yuanyuan Cheng
- Oil Tea Research Center of Fujian Province, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.C.); (L.Z.); (T.L.); (Y.L.)
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
- International Joint Laboratory of Forest Symbiology, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lexin Zhou
- Oil Tea Research Center of Fujian Province, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.C.); (L.Z.); (T.L.); (Y.L.)
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
| | - Tian Liang
- Oil Tea Research Center of Fujian Province, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.C.); (L.Z.); (T.L.); (Y.L.)
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
| | - Jiayin Man
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
- International Joint Laboratory of Forest Symbiology, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yinghao Wang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
- International Joint Laboratory of Forest Symbiology, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yu Li
- Oil Tea Research Center of Fujian Province, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.C.); (L.Z.); (T.L.); (Y.L.)
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
| | - Hui Chen
- Oil Tea Research Center of Fujian Province, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.C.); (L.Z.); (T.L.); (Y.L.)
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
- Correspondence: (H.C.); (T.Z.); Tel.: +86-139-5034-3791 (H.C.); +86-180-0691-1945 (T.Z.)
| | - Taoxiang Zhang
- Oil Tea Research Center of Fujian Province, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.C.); (L.Z.); (T.L.); (Y.L.)
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.M.); (Y.W.)
- International Joint Laboratory of Forest Symbiology, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Correspondence: (H.C.); (T.Z.); Tel.: +86-139-5034-3791 (H.C.); +86-180-0691-1945 (T.Z.)
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Gao Y, Xu X, Ding J, Bao F, De Costa YG, Zhuang W, Wu B. The Responses to Long-Term Water Addition of Soil Bacterial, Archaeal, and Fungal Communities in A Desert Ecosystem. Microorganisms 2021; 9:microorganisms9050981. [PMID: 33946616 PMCID: PMC8147197 DOI: 10.3390/microorganisms9050981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/22/2021] [Accepted: 04/28/2021] [Indexed: 12/13/2022] Open
Abstract
The response of microbial communities to continual and prolonged water exposure provides useful insight when facing global climate changes that cause increased and uneven precipitation and extreme rainfall events. In this study, we investigated an in situ manipulative experiment with four levels of water exposure (ambient precipitation +0%, +25%, +50%, and +100% of local annual mean precipitation) in a desert ecosystem of China. After 9 years of water addition, Illumina sequencing was used to analyze taxonomic compositions of the soil bacterial, archaeal, and fungal communities. The results showed significant increases in microbial biomass carbon (MBC) at higher amended precipitation levels, with the highest values reported at 100% precipitation. Furthermore, an increase in the bacterial species richness was observed along the water addition gradient. In addition, the relative abundance of several bacterial phyla, such as Proteobacteria, significantly increased, whereas that of some drought-tolerant taxa, including Actinobacteria, Firmicutes, and Bacteroidetes, decreased. In addition, the phyla Planctomycetes and Nitrospirae, associated with nitrification, positively responded to increased precipitation. Archaeal diversity significantly reduced under 100% treatment, with changes in the relative abundance of Thaumarchaeota and Euryarchaeota being the main contributors to shifts in the archaeal community. The fungal community composition was stable in response to water addition. Results from the Mantel test and structural equation models suggested that bacterial and archaeal communities reacted contrastingly to water addition. Bacterial community composition was directly affected by changing soil moisture and temperature, while archaeal community composition was indirectly affected by changing nitrogen availability. These findings highlight the importance of soil moisture and nitrogen in driving microbial responses to long-term precipitation changes in the desert ecosystem.
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Affiliation(s)
- Ying Gao
- Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China; (X.X.); (F.B.)
- Correspondence: (Y.G.); (B.W.); Tel.: +86-010-62824029 (Y.G.); +86-010-62824078 (B.W.)
| | - Xiaotian Xu
- Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China; (X.X.); (F.B.)
- Beijing Academy of Forestry and Pomology Sciences, Beijing 100093, China
| | - Junjun Ding
- Key Laboratory of Dryland Agriculture, Ministry of Agriculture, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
| | - Fang Bao
- Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China; (X.X.); (F.B.)
| | - Yashika G. De Costa
- Department of Civil and Environmental Engineering, The University of Auckland, Auckland 1023, New Zealand; (Y.G.D.C.); (W.Z.)
| | - Weiqin Zhuang
- Department of Civil and Environmental Engineering, The University of Auckland, Auckland 1023, New Zealand; (Y.G.D.C.); (W.Z.)
| | - Bo Wu
- Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China; (X.X.); (F.B.)
- Correspondence: (Y.G.); (B.W.); Tel.: +86-010-62824029 (Y.G.); +86-010-62824078 (B.W.)
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Zou Y, Ning D, Huang Y, Liang Y, Wang H, Duan L, Yuan T, He Z, Yang Y, Xue K, Van Nostrand JD, Zhou J. Functional structures of soil microbial community relate to contrasting N 2O emission patterns from a highly acidified forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 725:138504. [PMID: 32302850 DOI: 10.1016/j.scitotenv.2020.138504] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 04/04/2020] [Accepted: 04/04/2020] [Indexed: 05/23/2023]
Abstract
Nitrous oxide (N2O) is an important greenhouse gas contributing to global climate change. Emissions of N2O from acidic forests are increasing rapidly; however, little is known about the mechanisms driving these emissions. We analyzed soil samples from a high N2O emission area (HEA, 224-601 μg N m-2 h-1) and an adjacent low emission area (LEA, 20-30 μg N m-2 h-1) of a highly acidified forest. HEA showed similar carbon and nitrogen (N) pools and microbial biomass to LEA, but significantly higher moisture and extractable nutrients than LEA did. GeoChip 4 detected 298 gene families (unadjusted P < 0.05; 94, adjusted P < 0.05) showing significantly different structures between HEA and LEA. Both areas had highly diverse N cycling functional genes. However, HEA had higher relative abundances of nor, P450nor, and archaeal nitrifier nirK, which provided evidence for the importance of denitrifiers in N2O emission. HEA also showed significantly higher relative abundances of lignin- and cellulose-degrading genes, oxygen-limitation-response genes and denitrifier ppk, but lower abundances of N- and phosphorus (P) -limitation-response genes especially denitrifier pstS, corresponding to the higher moisture and extractable nutrients conducive to denitrification. The moisture, extractable nutrients and pH explained over 50% variation in microbial communities, and extractable P appeared as the key factor driving community variation and consequently regulated N2O production. CAPSULE ABSTRACT: N2O emission in highly acidified forest soils was related to the diverse N functional genes, especially denitrification genes, and was affected by soil properties.
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Affiliation(s)
- Yina Zou
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Daliang Ning
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China; Institute for Environmental Genomics, Department of Microbiology and Plant Biology, The University of Oklahoma, Norman, OK, USA
| | - Yong Huang
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Yuting Liang
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Hui Wang
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
| | - Lei Duan
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Tong Yuan
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, The University of Oklahoma, Norman, OK, USA
| | - Zhili He
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, The University of Oklahoma, Norman, OK, USA
| | - Yunfeng Yang
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Kai Xue
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, The University of Oklahoma, Norman, OK, USA
| | - Joy D Van Nostrand
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, The University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China; Institute for Environmental Genomics, Department of Microbiology and Plant Biology, The University of Oklahoma, Norman, OK, USA; Earth Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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Zheng M, Song J, Ru J, Zhou Z, Zhong M, Jiang L, Hui D, Wan S. Effects of Grazing, Wind Erosion, and Dust Deposition on Plant Community Composition and Structure in a Temperate Steppe. Ecosystems 2020. [DOI: 10.1007/s10021-020-00526-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zhou F, Ding J, Li T, Zhang X. Plant communities are more sensitive than soil microbial communities to multiple environmental changes in the Eurasian steppe. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2019.e00779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Progressive Microbial Community Networks with Incremental Organic Loading Rates Underlie Higher Anaerobic Digestion Performance. mSystems 2020; 5:5/1/e00357-19. [PMID: 31911462 PMCID: PMC6946792 DOI: 10.1128/msystems.00357-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although biotic interactions among members of microbial communities have been conceived to be crucial for community assembly, it remains unclear how changes in environmental conditions affect microbial interaction and consequently system performance. Here, we adopted a random matrix theory-based network analysis to explore microbial interactions in triplicate anaerobic digestion (AD) systems, which is widely applied for organic pollutant treatments. The digesters were operated with incremental organic loading rates (OLRs) from 1.0 g volatile solids (VS)/liter/day to 1.3 g VS/liter/day and then to 1.5 g VS/liter/day, which increased VS removal and methane production proportionally. Higher resource availability led to networks with higher connectivity and shorter harmonic geodesic distance, suggestive of more intense microbial interactions and quicker responses to environmental changes. Strikingly, a number of topological properties of microbial network showed significant (P < 0.05) correlation with AD performance (i.e., methane production, biogas production, and VS removal). When controlling for environmental parameters (e.g., total ammonia, pH, and the VS load), node connectivity, especially that of the methanogenic archaeal network, still correlated with AD performance. Last, we identified the Methanothermus, Methanobacterium, Chlorobium, and Haloarcula taxa and an unclassified Thaumarchaeota taxon as keystone nodes of the network.IMPORTANCE AD is a biological process widely used for effective waste treatment throughout the world. Biotic interactions among microbes are critical to the assembly and functioning of the microbial community, but the response of microbial interactions to environmental changes and their influence on AD performance are still poorly understood. Using well-replicated time series data of 16S rRNA gene amplicons and functional gene arrays, we constructed random matrix theory-based association networks to characterize potential microbial interactions with incremental OLRs. We demonstrated striking linkage between network topological features of methanogenic archaea and AD functioning independent of environmental parameters. As the intricate balance of multiple microbial functional groups is responsible for methane production, our results suggest that microbial interaction may be an important, previously unrecognized mechanism in determining AD performance.
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