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Yalçın G, Yıldız D, Calderó-Pascual M, Yetim S, Şahin Y, Parakatselaki ME, Avcı F, Karakaya N, Ladoukakis ED, Berger SA, Ger KA, Jeppesen E, Beklioğlu M. Quality matters: Response of bacteria and ciliates to different allochthonous dissolved organic matter sources as a pulsed disturbance in shallow lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:170140. [PMID: 38244618 DOI: 10.1016/j.scitotenv.2024.170140] [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: 09/25/2023] [Revised: 12/11/2023] [Accepted: 01/11/2024] [Indexed: 01/22/2024]
Abstract
Shallow lake ecosystems are particularly prone to disturbances such as pulsed dissolved organic matter (allochthonous-DOM; hereafter allo-DOM) loadings from catchments. However, the effects of allo-DOM with contrasting quality (in addition to quantity) on the planktonic communities of microbial loop are poorly understood. To determine the impact of different qualities of pulsed allo-DOM disturbance on the coupling between bacteria and ciliates, we conducted a mesocosm experiment with two different allo-DOM sources added to mesocosms in a single-pulse disturbance event: Alder tree leaf extract, a more labile (L) source and HuminFeed® (HF), a more recalcitrant source. Allo-DOM sources were used as separate treatments and in combination (HFL) relative to the control without allo-DOM additions (C). Our results indicate that the quality of allo-DOM was a major regulator of planktonic microbial community biomass and/or composition through which both bottom-up and top-down forces were involved. Bacteria biomass showed significant nonlinear responses in L and HFL with initial increases followed by decreases to pre-pulse conditions. Ciliate biomass was significantly higher in L compared to all other treatments. In terms of composition, bacterivore ciliate abundance was significantly higher in both L and HFL treatments, mainly driven by the bacterial biomass increase in the same treatments. GAMM models showed negative interaction between metazoan zooplankton biomass and ciliates, but only in the L treatment, indicating top-down control on ciliates. Ecosystem stability analyses revealed overperformance, high resilience and full recovery of bacteria in the HFL and L treatments, while ciliates showed significant shift in compositional stability in HFL and L with incomplete taxonomic recovery. Our study highlights the importance of allo-DOM quality shaping the response within the microbial loop not only through triggering different scenarios in biomass, but also the community composition, stability, and species interactions (top-down and bottom-up) in bacteria and plankton.
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Affiliation(s)
- Gülce Yalçın
- Limnology Laboratory, Biological Sciences Department, Middle East Technical University, 06800 Ankara, Turkey; Ecosystem Research and Implementation Center, Middle East Technical University, 06800 Ankara, Turkey.
| | - Dilvin Yıldız
- Limnology Laboratory, Biological Sciences Department, Middle East Technical University, 06800 Ankara, Turkey; Earth System Sciences, Graduate School of Natural and Applied Science, Middle East Technical University, Ankara, Turkey.
| | - Maria Calderó-Pascual
- Centre for Freshwater and Environmental Studies, Dundalk Institute of Technology, Dundalk, Marshes Upper, Co. Louth A91 K584, Ireland..
| | - Sinem Yetim
- Limnology Laboratory, Biological Sciences Department, Middle East Technical University, 06800 Ankara, Turkey
| | - Yiğit Şahin
- Department of Biotechnology, Graduate School of Natural and Applied Sciences, Ege University, 35100 Izmir, Turkey; Department of Bioengineering, Faculty of Engineering, Ege University, 35100, Izmir, Turkey
| | | | - Feride Avcı
- Limnology Laboratory, Biological Sciences Department, Middle East Technical University, 06800 Ankara, Turkey.
| | | | - Emmanuel D Ladoukakis
- Department of Biology, University of Crete, Voutes University Campus, 70013 Heraklion, Greece.
| | - Stella A Berger
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Department of Plankton and Microbial Ecology, Zur alten Fischerhuette 2, 16775 Stechlin, Germany.
| | - Kemal Ali Ger
- Department of Ecology (DECOL), Federal University of Rio Grande do Norte, Natal, RN 59078-970, Brazil..
| | - Erik Jeppesen
- Limnology Laboratory, Biological Sciences Department, Middle East Technical University, 06800 Ankara, Turkey; Ecosystem Research and Implementation Center, Middle East Technical University, 06800 Ankara, Turkey; Department of Ecoscience, Aarhus University, 8000C Aarhus, Denmark; Sino-Danish Centre for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, China.
| | - Meryem Beklioğlu
- Limnology Laboratory, Biological Sciences Department, Middle East Technical University, 06800 Ankara, Turkey; Ecosystem Research and Implementation Center, Middle East Technical University, 06800 Ankara, Turkey.
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Koloti LE, Nkuna R, Matambo TS. Impact of current anthropogenic activities on Blesbokspruit wetland microbiome and functions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:170010. [PMID: 38219994 DOI: 10.1016/j.scitotenv.2024.170010] [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: 05/16/2023] [Revised: 01/03/2024] [Accepted: 01/06/2024] [Indexed: 01/16/2024]
Abstract
Till present, natural wetlands have been continuously subjected to intensive pollution stress in recent years, mainly because of the rapidly growing industrialization and urbanization that are associated with a myriad of anthropogenic activities and land use practices. These man-made sources of pollution change the chemical properties of the natural wetlands, which in turn alter their microbial ecological biodiversity and functions. For the first time, the impact of the current anthropogenic activities and land use practices on the Blesbokspruit wetland chemical status and their consequential effect on the microbial structure and functions were investigated. Sites of high pollution intensity were identified using geographic information systems mapping (GISMapping) and the wetland microbiome and functional profile were studied through the use of high throughput shotgun metagenomics sequencing analysis. The predominant phyla that stemmed along the Blesbokspruit wetland were found to be Proteobacteria which was more dominant in water (93 %) than in the sediments (89 %), followed by firmicutes which was more abundant in sediments (9 %) than in water (6 %), and Bacteroidetes were relatively low in abundance within both the sediments (2 %) and the overlying water (1 %). The genera Klebsiella (70.4 %-28.2 %), Citrobacter (52.0 %-30.6 %), Escherichia (51.0 %-8.4 %), and Lynsinibacillus (9.3 %-1.5 %) were observed in most water and sediment samples. Within the six polluted sites, Site 2 was found to be the most highly polluted site in the Blesbokspruit wetland with very high COD (900 mg/L), TOC (11.60 mg/L), NO3- (39.74 mg/L), NO2- (12.64 mg/L), PO43 (4.14 mg/L), Fl- (143.88 mg/L), Cl- (145.95 mg/L) concentrations recorded in the water and high levels of TOC (0.37 mg/L), TC (6.92 %), TN (1.82 %), TS (0.53 %) in sediments. The microbial community structure and functions were found to be strongly influenced by the high organic content from the intense agricultural activities and sewage spillages and heavy metals from the mining activities nearby.
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Affiliation(s)
- Lebohang E Koloti
- Institute for the Development of Energy for African Sustainability (IDEAS), University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa
| | - Rosina Nkuna
- Institute for the Development of Energy for African Sustainability (IDEAS), University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa
| | - Tonderayi S Matambo
- Institute for the Development of Energy for African Sustainability (IDEAS), University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa; Centre of Competence in Environmental Biotechnology, College of Agriculture and Environmental Sciences, University of South Africa, Christiaan De Wet/Pioneer, P.O. Box X6, FL 1710, South Africa.
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Kajan K, Osterholz H, Stegen J, Gligora Udovič M, Orlić S. Mechanisms shaping dissolved organic matter and microbial community in lake ecosystems. WATER RESEARCH 2023; 245:120653. [PMID: 37742402 DOI: 10.1016/j.watres.2023.120653] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/17/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023]
Abstract
Lakes are active components of the global carbon cycle and host a range of processes that degrade and modify dissolved organic matter (DOM). Through the degradation of DOM molecules and the synthesis of new compounds, microbes in aquatic environments strongly and continuously influence chemodiversity, which can feedback to influence microbial diversity. Developing a better understanding of the biodiversity patterns that emerge along spatial and environmental gradients is one of the key objectives of community ecology. A changing climate may affect ecological feedback, including those that affect microbial communities. To maintain the function of a lake ecosystem and predict carbon cycling in the environment, it is increasingly important to understand the coupling between microbial and DOM diversity. To unravel the biotic and abiotic mechanisms that control the structure and patterns of DOM and microbial communities in lakes, we combined high-throughput sequencing and ultra-high resolution mass spectrometry together with a null modeling approach. The advantage of null models is their ability to evaluate the relative influences of stochastic and deterministic assembly processes in both DOM and microbial community assemblages. The present study includes spatiotemporal signatures of DOM and the microbial community in six temperate lakes contrasting continental and Mediterranean climates during the productive season. Different environmental conditions and nutrient sources characterized the studied lakes. Our results have shown high covariance between molecular-level DOM diversity and the diversity of individual microbial communities especially with diversity of microeukaryotes and free-living bacteria indicating their dynamic feedback. We found that the differences between lakes and climatic regions were mainly reflected in the diversity of DOM at the molecular formula-level and the microeukaryota community. Furthermore, using null models the DOM assembly was governed by deterministic variable selection operating consistently and strongly within and among lakes. In contrast, microbial community assembly processes were highly variable across lakes with different trophic status and climatic regions. Difference in the processes governing DOM and microbial composition does not indicate weak coupling between these components, rather it suggests that distinct factors may be influencing microbial communities and DOM assemblages separately. Further understanding of the DOM-microbe coupling (or lack thereof) is key to formulating predictive models of future lake ecology and function.
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Affiliation(s)
- Katarina Kajan
- Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; Center of Excellence for Science and Technology-Integration of Mediterranean Region (STIM), Split, Croatia
| | - Helena Osterholz
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany; Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| | - James Stegen
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P. O. Box 999, Richland, WA 99352, USA
| | - Marija Gligora Udovič
- Department of Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
| | - Sandi Orlić
- Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; Center of Excellence for Science and Technology-Integration of Mediterranean Region (STIM), Split, Croatia.
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Sagua MI, Nuozzi G, Sánchez ML, Huber P, Perdomo S, Schiaffino MR. Unraveling the effect of land use on the bacterioplankton community composition from highly impacted shallow lakes at a regional scale. FEMS Microbiol Ecol 2023; 99:fiad109. [PMID: 37715304 DOI: 10.1093/femsec/fiad109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 09/17/2023] Open
Abstract
Bacterioplankton communities play a crucial role in global biogeochemical processes and are highly sensitive to changes induced by natural and anthropogenic stressors in aquatic ecosystems. We assessed the influence of Land Use Land Cover (LULC), environmental, and geographic changes on the bacterioplankton structure in highly connected and impacted shallow lakes within the Salado River basin, Buenos Aires, Argentina. Additionally, we investigated how changes in LULC affected the limnological characteristics of these lakes at a regional scale. Our analysis revealed that the lakes were ordinated by sub-basins (upper and lower) depending on their LULC characteristics and limnological properties. In coincidence, the same ordination was observed when considering the Bacterioplankton Community Composition (BCC). Spatial and environmental predictors significantly explained the variation in BCC, although when combined with LULC the effect was also important. While the pure LULC effect did not explain a significant percentage of BCC variation, the presence of atrazine in water, an anthropogenic variable linked to LULC, directly influenced both the BCC and some Amplicon Sequence Variants (ASVs) in particular. Our regional-scale approach contributes to understanding the complexity of factors driving bacterioplankton structure and how LULC pervasively affect these communities in highly impacted shallow lake ecosystems from the understudied Southern Hemisphere.
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Affiliation(s)
- Mara I Sagua
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Roque Saez Pena 456 (6000), Junín, Buenos Aires, Argentina
- Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires (CIT NOBA) - UNNOBA-UNSAdA-CONICET, Monteagudo 2772 (2700), Pergamino, Buenos Aires, Argentina
| | - Guillermina Nuozzi
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Roque Saez Pena 456 (6000), Junín, Buenos Aires, Argentina
- Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires (CIT NOBA) - UNNOBA-UNSAdA-CONICET, Monteagudo 2772 (2700), Pergamino, Buenos Aires, Argentina
| | - María L Sánchez
- CONICET - Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Universidad de Buenos Aires, Intendente Guiraldes 2160 (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, Intendente Guiraldes 2160 (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Paula Huber
- Instituto Nacional de Limnología (INALI, CONICET-UNL). Colectora RN 168 Km 0 (3000), Paraje El Pozo, Santa Fe, Argentina
- Departamento de Hydrobiologia, Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luis S/N - Monjolinho (13565-905), São Carlos, São Paulo, Brazil
| | - Santiago Perdomo
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Roque Saez Pena 456 (6000), Junín, Buenos Aires, Argentina
- Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires (CIT NOBA) - UNNOBA-UNSAdA-CONICET, Monteagudo 2772 (2700), Pergamino, Buenos Aires, Argentina
| | - María R Schiaffino
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Roque Saez Pena 456 (6000), Junín, Buenos Aires, Argentina
- Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires (CIT NOBA) - UNNOBA-UNSAdA-CONICET, Monteagudo 2772 (2700), Pergamino, Buenos Aires, Argentina
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Sylvain FÉ, Bouslama S, Holland A, Leroux N, Mercier PL, Val AL, Derome N. Bacterioplankton Communities in Dissolved Organic Carbon-Rich Amazonian Black Water. Microbiol Spectr 2023; 11:e0479322. [PMID: 37199657 PMCID: PMC10269884 DOI: 10.1128/spectrum.04793-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 05/04/2023] [Indexed: 05/19/2023] Open
Abstract
The Amazon River basin sustains dramatic hydrochemical gradients defined by three water types: white, clear, and black waters. In black water, important loads of allochthonous humic dissolved organic matter (DOM) result from the bacterioplankton degradation of plant lignin. However, the bacterial taxa involved in this process remain unknown, since Amazonian bacterioplankton has been poorly studied. Its characterization could lead to a better understanding of the carbon cycle in one of the Earth's most productive hydrological systems. Our study characterized the taxonomic structure and functions of Amazonian bacterioplankton to better understand the interplay between this community and humic DOM. We conducted a field sampling campaign comprising 15 sites distributed across the three main Amazonian water types (representing a gradient of humic DOM), and a 16S rRNA metabarcoding analysis based on bacterioplankton DNA and RNA extracts. Bacterioplankton functions were inferred using 16S rRNA data in combination with a tailored functional database from 90 Amazonian basin shotgun metagenomes from the literature. We discovered that the relative abundances of fluorescent DOM fractions (humic-, fulvic-, and protein-like) were major drivers of bacterioplankton structure. We identified 36 genera for which the relative abundance was significantly correlated with humic DOM. The strongest correlations were found in the Polynucleobacter, Methylobacterium, and Acinetobacter genera, three low abundant but omnipresent taxa that possessed several genes involved in the main steps of the β-aryl ether enzymatic degradation pathway of diaryl humic DOM residues. Overall, this study identified key taxa with DOM degradation genomic potential, the involvement of which in allochthonous Amazonian carbon transformation and sequestration merits further investigation. IMPORTANCE The Amazon basin discharge carries an important load of terrestrially derived dissolved organic matter (DOM) to the ocean. The bacterioplankton from this basin potentially plays important roles in transforming this allochthonous carbon, which has consequences on marine primary productivity and global carbon sequestration. However, the structure and function of Amazonian bacterioplanktonic communities remain poorly studied, and their interactions with DOM are unresolved. In this study, we (i) sampled bacterioplankton in all the main Amazon tributaries, (ii) combined information from the taxonomic structure and functional repertory of Amazonian bacterioplankton communities to understand their dynamics, (iii) identified the main physicochemical parameters shaping bacterioplanktonic communities among a set of >30 measured environmental parameters, and (iv) characterized how bacterioplankton structure varies according to the relative abundance of humic compounds, a by-product from the bacterial degradation process of allochthonous DOM.
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Affiliation(s)
| | - Sidki Bouslama
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Quebec, Canada
| | - Aleicia Holland
- La Trobe University, School of Life Science, Department of Ecology, Environment and Evolution, Centre for Freshwater Ecosystems, Albury/Wodonga Campus, Victoria, Australia
| | - Nicolas Leroux
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Quebec, Canada
| | - Pierre-Luc Mercier
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Quebec, Canada
| | - Adalberto Luis Val
- Instituto Nacional de Pesquisas da Amazônia, Laboratório de Ecofisiologia e Evolução Molecular, Manaus, Brazil
| | - Nicolas Derome
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Quebec, Canada
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Differential Effects of Viruses on the Growth Efficiency of Freshwater Bacterioplankton in Eutrophic Relative to Non-Eutrophic Lakes. Microorganisms 2023; 11:microorganisms11020384. [PMID: 36838349 PMCID: PMC9966266 DOI: 10.3390/microorganisms11020384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/04/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
In aquatic environments, the consensus of viral impact on bacterial carbon metabolism with the nutrient environment as an important axis is limited. Henceforth, we explored the viral regulation of carbon-based bacterial growth efficiency (BGE) in a set of freshwater systems from French Massif Central, which were broadly classified based on two trophic statuses: eutrophic and non-eutrophic lakes. Comparative analysis showed that microbial abundances (viruses and bacteria) were 3-fold higher in eutrophic compared with non-eutrophic lakes, and so were bacterial production and viral lytic infection. The observed variability in BGE (10-60%) was explained by the uncoupling between bacterial respiration and production. Viruses through selective lysis of susceptible host communities had an antagonistic impact on BGE in the eutrophic lakes, whereas the release of substrates via viral shunt exerted a synergistic influence on the carbon metabolism of non-targeted host populations in non-eutrophic lakes. The decisive effect of the two individual processes (i.e., lysis and substrate release) on BGE was supported by regressions of bacterial abundance as a function of bacterial production, which is considered as a proxy of top-down processes. The role of viruses through their negative impact via mortality and positive impact via substrate supply can eventually have implications on carbon transfer through bacterioplankton in freshwaters.
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Humic Lake Exhibits Higher Microbial Functional Gene Diversity and Weaker Gene Interaction Efficiency than a Common Alkaline Lake. BIOLOGY 2022; 11:biology11101448. [PMID: 36290352 PMCID: PMC9598760 DOI: 10.3390/biology11101448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/16/2022] [Accepted: 09/27/2022] [Indexed: 11/05/2022]
Abstract
Humic lakes (HLs) are special water bodies (high organic matter content, low pH, and low transparency) that are important sources of major greenhouse gases. The knowledge about microbial functional potentials and the interactions among different genes in HL water has been scarcely understood. In this study, we used 16S rRNA gene sequencing and the GeoChip 5.0 to investigate microbial community compositions and functional gene structures in an HL and a reference weakly alkaline lake (RAL). The HL microbial communities showed distinct compositions and functional gene structures than those in the RAL. The functional gene diversity was significantly higher in the HL than in the RAL. Specifically, higher gene relative intensities in carbon and nitrogen fixations, the degradation of various types of carbon, methane oxidation and methanogenesis, ammonification, denitrification, and assimilatory N reduction were observed in the HL samples. By contrast, the metabolic potentials of microorganisms involved in dissimilatory N reduction, phosphorus degradation, and sulfur oxidation were weaker in the HL than in the RAL. Despite higher functional gene diversity, the interaction efficiency among genes (reflected by network geodesic distance and clustering coefficient) might be reduced in the HL. Different functional microbes may develop less interdependent relationships in acquiring nutrients given the high resource availability in the HL. Overall, the enhanced microbial metabolic potentials and less efficient functional interactions might have great consequences on nutrient cycling and greenhouse gas emissions in the HL ecosystem.
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Xu Q, Du Z, Wang L, Xue K, Wei Z, Zhang G, Liu K, Lin J, Lin P, Chen T, Xiao C. The Role of Thermokarst Lake Expansion in Altering the Microbial Community and Methane Cycling in Beiluhe Basin on Tibetan Plateau. Microorganisms 2022; 10:1620. [PMID: 36014037 PMCID: PMC9412574 DOI: 10.3390/microorganisms10081620] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/05/2022] [Accepted: 08/07/2022] [Indexed: 11/16/2022] Open
Abstract
One of the most significant environmental changes across the Tibetan Plateau (TP) is the rapid lake expansion. The expansion of thermokarst lakes affects the global biogeochemical cycles and local climate regulation by rising levels, expanding area, and increasing water volumes. Meanwhile, microbial activity contributes greatly to the biogeochemical cycle of carbon in the thermokarst lakes, including organic matter decomposition, soil formation, and mineralization. However, the impact of lake expansion on distribution patterns of microbial communities and methane cycling, especially those of water and sediment under ice, remain unknown. This hinders our ability to assess the true impact of lake expansion on ecosystem services and our ability to accurately investigate greenhouse gas emissions and consumption in thermokarst lakes. Here, we explored the patterns of microorganisms and methane cycling by investigating sediment and water samples at an oriented direction of expansion occurred from four points under ice of a mature-developed thermokarst lake on TP. In addition, the methane concentration of each water layer was examined. Microbial diversity and network complexity were different in our shallow points (MS, SH) and deep points (CE, SH). There are differences of microbial community composition among four points, resulting in the decreased relative abundances of dominant phyla, such as Firmicutes in sediment, Proteobacteria in water, Thermoplasmatota in sediment and water, and increased relative abundance of Actinobacteriota with MS and SH points. Microbial community composition involved in methane cycling also shifted, such as increases in USCγ, Methylomonas, and Methylobacter, with higher relative abundance consistent with low dissolved methane concentration in MS and SH points. There was a strong correlation between changes in microbiota characteristics and changes in water and sediment environmental factors. Together, these results show that lake expansion has an important impact on microbial diversity and methane cycling.
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Affiliation(s)
- Qian Xu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiheng Du
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Lei Wang
- Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Zhuhai 519087, China
| | - Kai Xue
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiqiang Wei
- Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Zhuhai 519087, China
| | - Gaosen Zhang
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730000, China
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Keshao Liu
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Jiahui Lin
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
| | - Penglin Lin
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
| | - Tuo Chen
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730000, China
| | - Cunde Xiao
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
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Calderini ML, Salmi P, Rigaud C, Peltomaa E, Taipale SJ. Metabolic plasticity of mixotrophic algae is key for their persistence in browning environments. Mol Ecol 2022; 31:4726-4738. [PMID: 35844067 PMCID: PMC9544590 DOI: 10.1111/mec.16619] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 07/06/2022] [Accepted: 07/11/2022] [Indexed: 11/30/2022]
Abstract
Light availability is the main regulator of primary production, shaping photosynthetic communities and their production of ecologically important biomolecules. In freshwater ecosystems, increasing dissolved organic carbon (DOC) concentrations, commonly known as browning, leads to lower light availability and the proliferation of mixotrophic phytoplankton. Here, a mixotrophic algal species (Cryptomonas sp.) was grown under five increasing DOC concentrations to uncover the plastic responses behind the success of mixotrophs in browning environments and their effect in the availability of nutritionally important biomolecules. In addition to the browning treatments, phototrophic, heterotrophic and mixotrophic growth conditions were used as controls. Despite reduced light availability, browning did not impair algal growth compared to phototrophic conditions. Comparative transcriptomics showed that genes related to photosynthesis were down‐regulated, whereas phagotrophy gene categories (phagosome, lysosome and endocytosis) were up‐regulated along the browning gradient. Stable isotope analysis of phospholipid fractions validated these results, highlighting that the studied mixotroph increases its reliance on heterotrophic processes with browning. Metabolic pathway reconstruction using transcriptomic data suggests that organic carbon is acquired through phagotrophy and used to provide energy in conjunction with photosynthesis. Although metabolic responses to browning were observed, essential fatty acid content was similar between treatments while sterol content was slightly higher upon browning. Together, our results provide a mechanistic model of how a mixotrophic alga responds to browning and how such responses affect the availability of nutritionally essential biomolecules for higher trophic levels.
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Affiliation(s)
- Marco L Calderini
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Department of Biological and Environmental Science, University of Jyvaskyla, Finland
| | - Pauliina Salmi
- Spectral Imaging Laboratory, Faculty of Information Technology, University of Jyväskylä, Jyväskylä, Finland
| | - Cyril Rigaud
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Elina Peltomaa
- Institute of Atmospheric and Earth System Research (INAR)/Forest Sciences, University of Helsinki, Helsinki, Finland.,Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Helsinki, Finland
| | - Sami J Taipale
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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10
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DeWolf EI, Calder WJ, Harrison JG, Randolph GD, Noren BE, Weinig C. Aquatic Macrophytes Are Associated With Variation in Biogeochemistry and Bacterial Assemblages of Mountain Lakes. Front Microbiol 2022; 12:777084. [PMID: 35154025 PMCID: PMC8828945 DOI: 10.3389/fmicb.2021.777084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/16/2021] [Indexed: 01/04/2023] Open
Abstract
In aquatic systems, microbes likely play critical roles in biogeochemical cycling and ecosystem processes, but much remains to be learned regarding microbial biogeography and ecology. The microbial ecology of mountain lakes is particularly understudied. We hypothesized that microbial distribution among lakes is shaped, in part, by aquatic plant communities and the biogeochemistry of the lake. Specifically, we investigated the associations of yellow water lilies (Nuphar polysepala) with the biogeochemistry and microbial assemblages within mountain lakes at two scales: within a single lake and among lakes within a mountain range. We first compared the biogeochemistry of lakes without water lilies to those colonized to varying degrees by water lilies. Lakes with >10% of the surface occupied by water lilies had lower pH and higher dissolved organic carbon than those without water lilies and had a different microbial composition. Notably, cyanobacteria were negatively associated with water lily presence, a result consistent with the past observation that macrophytes outcompete phytoplankton and can suppress cyanobacterial and algal blooms. To examine the influence of macrophytes on microbial distribution within a lake, we characterized microbial assemblages present on abaxial and adaxial water lily leaf surfaces and in the water column. Microbial diversity and composition varied among all three habitats, with the highest diversity of microbes observed on the adaxial side of leaves. Overall, this study suggests that water lilies influence the biogeochemistry and microbiology of mountains lakes.
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Affiliation(s)
- Ella Ide DeWolf
- Department of Botany, University of Wyoming, Laramie, WY, United States
- *Correspondence: Ella Ide DeWolf,
| | | | | | | | | | - Cynthia Weinig
- Department of Botany, University of Wyoming, Laramie, WY, United States
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11
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Tandon K, Wan MT, Yang CC, Yang SH, Baatar B, Chiu CY, Tsai JW, Liu WC, Ng CS, Tang SL. Aquatic microbial community is partially functionally redundant: Insights from an in situ reciprocal transplant experiment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 786:147433. [PMID: 33971597 DOI: 10.1016/j.scitotenv.2021.147433] [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: 03/03/2021] [Revised: 04/06/2021] [Accepted: 04/25/2021] [Indexed: 06/12/2023]
Abstract
Microbial communities are considered to be functionally redundant, but few studies have tested this hypothesis empirically. In this study, we performed an in situ reciprocal transplant experiment on the surface and bottom waters of two lakes (Tsuei-Feng (T) and Yuan-Yang (Y)) with disparate trophic states and tracked changes in their microbial community composition and functions for 6 weeks using high-throughput sequencing and functional approaches. T lake's surface (Ts) and bottom (Tb) water active bacterial community (16S rRNA gene-transcript) was dominated by Actinobacteria, Bacteroidia, and Cyanobacteria, whereas Y lake's surface (Ys) and bottom (Yb) water had Gammaproteobacteria, Alphaproteobacteria, and Bacteroidia as the dominant classes. The community composition was resistant to changes in environmental conditions following the reciprocal transplant, but their functions tended to become similar to the incubating lakes' functional profiles. A significant linear positive relationship was observed between the microbial community and functional attributes (surface: R2 = 0.5065, p < 0.0001; bottom: R2 = 0.4592, p < 0.0001), though with varying scales of similarity (1-Bray Curtis distance), suggesting partial functional redundancy. Also, the entropy-based L-divergence measure identified high divergence in community composition (surface: 1.21 ± 0.54; bottom: 1.17 ± 0.51), and relatively low divergence in functional attributes (surface: 0.04 ± 0.01; bottom: 0.04 ± 0.01) in the two lakes' surface and bottom waters, providing further support for the presence of partial functional redundancy. This study enriches our understanding of community functional relationships and establishes the presence of partial functional redundancy in freshwater ecosystems.
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Affiliation(s)
- Kshitij Tandon
- Biodiversity Research Center, Academia Sinica, Taipei 11529, Taiwan; Bioinformatics Program, Institute of Information Science, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan; Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Min-Tao Wan
- EcoHealth Microbiology Laboratory, WanYu Co., Ltd., Chiayi 600, Taiwan
| | - Chia-Chin Yang
- Biodiversity Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Shan-Hua Yang
- Institute of Fisheries Science, National Taiwan University, Taipei 10617, Taiwan
| | | | - Chih-Yu Chiu
- Biodiversity Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Jeng-Wei Tsai
- China Medical University, Department of Biological Science and Technology, Taichung 404, Taiwan
| | - Wen-Cheng Liu
- Department of Civil and Disaster Prevention Engineering, National United University, Miao-Li, Taiwan
| | - Chen Siang Ng
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Sen-Lin Tang
- Biodiversity Research Center, Academia Sinica, Taipei 11529, Taiwan; Bioinformatics Program, Institute of Information Science, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan.
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12
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Fontaine L, Khomich M, Andersen T, Hessen DO, Rasconi S, Davey ML, Eiler A. Multiple thresholds and trajectories of microbial biodiversity predicted across browning gradients by neural networks and decision tree learning. ISME COMMUNICATIONS 2021; 1:37. [PMID: 37938633 PMCID: PMC9723588 DOI: 10.1038/s43705-021-00038-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/27/2021] [Accepted: 07/30/2021] [Indexed: 08/20/2023]
Abstract
Ecological association studies often assume monotonicity such as between biodiversity and environmental properties although there is growing evidence that nonmonotonic relations dominate in nature. Here, we apply machine-learning algorithms to reveal the nonmonotonic association between microbial diversity and an anthropogenic-induced large-scale change, the browning of freshwaters, along a longitudinal gradient covering 70 boreal lakes in Scandinavia. Measures of bacterial richness and evenness (alpha-diversity) showed nonmonotonic trends in relation to environmental gradients, peaking at intermediate levels of browning. Depending on the statistical methods, variables indicative for browning could explain 5% of the variance in bacterial community composition (beta-diversity) when applying standard methods assuming monotonic relations and up to 45% with machine-learning methods taking non-monotonicity into account. This non-monotonicity observed at the community level was explained by the complex interchangeable nature of individual taxa responses as shown by a high degree of nonmonotonic responses of individual bacterial sequence variants to browning. Furthermore, the nonmonotonic models provide the position of thresholds and predict alternative bacterial diversity trajectories in boreal freshwater as a result of ongoing climate and land-use changes, which in turn will affect entire ecosystem metabolism and likely greenhouse gas production.
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Affiliation(s)
- Laurent Fontaine
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Maryia Khomich
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Tom Andersen
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dag O Hessen
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Serena Rasconi
- Université Savoie Mont Blanc, INRAE, CARRTEL, Thonon-les-Bains, France
| | - Marie L Davey
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Alexander Eiler
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway.
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway.
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13
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Dey J, Vijay R. A critical and intensive review on assessment of water quality parameters through geospatial techniques. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:41612-41626. [PMID: 34105074 DOI: 10.1007/s11356-021-14726-4] [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: 01/11/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
Evaluation of water quality is a priority work nowadays. In order to monitor and map, the water quality for a wide range on different scales (spatial, temporal), the geospatial technique has the potential to minimize the field and laboratory work. The review has emphasized the advance of remote sensing for the effectiveness of spectral analysis, bio-optical estimation, empirical method, and application of machine learning for water quality assessment. The water quality parameters (turbidity, suspended particles, chlorophyll, etc.) and their retrieval techniques are described in a scientific manner. Available satellite, bands, resolution, and spectrum ranges for specific parameters are critically described in this review with challenges in remote sensing for water quality analysis, considering non-optical active parameters. The application of statistical programmes like linear (multiple regression analysis) and non-linear approaches is discussed for better assessment of water quality. Emphasis is given on comparison between different models to increase the accuracy level of remote sensing of water quality assessment. A direction is suggested for future development in the field of estimation of water pollution assessment through geospatial techniques.
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Affiliation(s)
- Jaydip Dey
- Wastewater Technology Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nagpur, Maharashta, 440020, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India
| | - Ritesh Vijay
- Wastewater Technology Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nagpur, Maharashta, 440020, India.
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14
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Hofmann R, Uhl J, Hertkorn N, Griebler C. Linkage Between Dissolved Organic Matter Transformation, Bacterial Carbon Production, and Diversity in a Shallow Oligotrophic Aquifer: Results From Flow-Through Sediment Microcosm Experiments. Front Microbiol 2020; 11:543567. [PMID: 33250862 PMCID: PMC7674671 DOI: 10.3389/fmicb.2020.543567] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 09/10/2020] [Indexed: 11/24/2022] Open
Abstract
Aquifers are important reservoirs for organic carbon. A fundamental understanding of the role of groundwater ecosystems in carbon cycling, however, is still missing. Using sediment flow-through microcosms, long-term (171d) experiments were conducted to test two scenarios. First, aquifer sediment microbial communities received dissolved organic matter (DOM) at low concentration and typical to groundwater in terms of composition (DOM-1x). Second, sediments received an elevated concentration of DOM originating from soil (DOM-5x). Changes in DOM composition were analyzed via NMR and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Carbon production, physiological adaptations and biodiversity of groundwater, and sediment prokaryotic communities were monitored by total cell counts, substrate use arrays, and deep amplicon sequencing. The experiments showed that groundwater microbial communities do not react very fast to the sudden availability of labile organic carbon from soil in terms of carbon degradation and biomass production. It took days to weeks for incoming DOM being efficiently degraded and pronounced cell production occurred. Once conditioned, the DOM-1x supplied sediments mineralized 294(±230) μgC L−1sed d−1, 10-times less than the DOM-5x fed sediment communities [2.9(±1.1) mgC L−1sed d−1]. However, the overall biomass carbon production was hardly different in the two treatments with 13.7(±4.8) μgC L−1sed d−1 and 14.3(±3.5) μgC L−1sed d−1, respectively, hinting at a significantly lower carbon use efficiency with higher DOM availability. However, the molecularly more diverse DOM from soil fostered a higher bacterial diversity. Taking the irregular inputs of labile DOM into account, shallow aquifers are assumed to have a low resilience. Lacking a highly active and responsive microbial community, oligotrophic aquifers are at high risk of contamination with organic chemicals.
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Affiliation(s)
- Roland Hofmann
- Institute of Groundwater Ecology, Helmholtz Center Munich, Neuherberg, Germany
| | - Jenny Uhl
- Research Unit Analytical Biogeochemistry, Helmholtz Center Munich, Neuherberg, Germany
| | - Norbert Hertkorn
- Research Unit Analytical Biogeochemistry, Helmholtz Center Munich, Neuherberg, Germany
| | - Christian Griebler
- Institute of Groundwater Ecology, Helmholtz Center Munich, Neuherberg, Germany.,Division of Limnology, Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
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15
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Mayr MJ, Besemer K, Sieczko A, Demeter K, Peduzzi P. Bacterial community composition and function along spatiotemporal connectivity gradients in the Danube floodplain (Vienna, Austria). AQUATIC SCIENCES 2020; 82:28. [PMID: 32165802 PMCID: PMC7045780 DOI: 10.1007/s00027-020-0700-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 01/02/2020] [Indexed: 05/25/2023]
Abstract
It is well recognized that river-floodplain systems contribute significantly to riverine ecosystem metabolism, and that bacteria are key players in the aquatic organic carbon cycle, but surprisingly few studies have linked bacterial community composition (BCC), function and carbon quality in these hydrologically highly dynamic habitats. We investigated aquatic BCC and extracellular enzymatic activity (EEA) related to dissolved organic carbon quality and algae composition, including the impact of a major flood event in one of the last remaining European semi-natural floodplain-systems. We found that surface connectivity of floodplain pools homogenizes BCC and EEA, whereas low connectivity led to increased BCC and EEA heterogeneity, supported by their relationship to electrical conductivity, an excellent indicator for surface connection strength. Hydrogeochemical parameters best explained variation of both BCC and EEA, while the algal community and chromophoric DOM properties explained only minor fractions of BCC variation. We conclude that intermittent surface connectivity and especially permanent isolation of floodplain pools from the main river channel may severely alter BCC and EEA, with potential consequences for nutrient cycling, ecological services and greenhouse gas emissions. Disentangling microbial structure-function coupling is therefore crucial, if we are to understand and predict the consequences of human alterations on these dynamic systems.
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Affiliation(s)
- Magdalena J. Mayr
- Department of Limnology and Oceanography, University of Vienna, Althanstrasse 14, 1090 Wien, Austria
| | - Katharina Besemer
- WasserCluster Lunz, Dr. Carl Kupelwieser Promenade 5, 3293 Lunz Am See, Austria
| | - Anna Sieczko
- Department of Limnology and Oceanography, University of Vienna, Althanstrasse 14, 1090 Wien, Austria
- Department of Thematic Studies–Environmental Change, Linköping University, Tema M, Campus Valla, 581 83 Linköping, Sweden
| | - Katalin Demeter
- Department of Limnology and Oceanography, University of Vienna, Althanstrasse 14, 1090 Wien, Austria
| | - Peter Peduzzi
- Department of Limnology and Oceanography, University of Vienna, Althanstrasse 14, 1090 Wien, Austria
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16
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Baña Z, Abad N, Uranga A, Azúa I, Artolozaga I, Unanue M, Iriberri J, Arrieta JM, Ayo B. Recurrent seasonal changes in bacterial growth efficiency, metabolism and community composition in coastal waters. Environ Microbiol 2019; 22:369-380. [PMID: 31713276 DOI: 10.1111/1462-2920.14853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 09/25/2019] [Accepted: 11/03/2019] [Indexed: 11/28/2022]
Abstract
The microbial response to environmental changes in coastal waters of the eastern Cantabrian Sea was explored for four years by analysing a broad set of environmental variables along with bacterial community metabolism and composition. A recurrent seasonal cycle emerged, consisting of two stable periods, characterized by low bacterial metabolic activity (winter) from October to March, and high bacterial metabolic activity (summer) from May to August. These two contrasting periods were linked by short transition periods in April (TA ) and September (TS ). The phylogenetic groups Alphaproteobacteria and Bacteroidetes were dominant during winter and summer respectively, and their recurrent alternation was mainly driven by the bloom of eukaryotic phytoplankton before TA and the bloom of prokaryotic phytoplankton before TS . Bacterial growth efficiency remained high and stable during the winter and summer periods but dropped during the two short transition periods. Our results suggest that bacterial growth efficiency should be considered a very resilient property that reflects different stages in the adaptation of the bacterial community composition to the environmental changes occurring throughout the seasonal cycle in this coastal ecosystem.
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Affiliation(s)
- Zuriñe Baña
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain
| | - Naiara Abad
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain
| | - Ainhoa Uranga
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain
| | - Iñigo Azúa
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain
| | - Itxaso Artolozaga
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain
| | - Marian Unanue
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain
| | - Juan Iriberri
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain.,Research Centre for Experimental Marine Biology and Biotechnology PiE-UPV/EHU, Areatza Hiribidea 47, Plentzia, 48620, Spain
| | - Jesus M Arrieta
- Oceanographic Center of Canary Island, Spanish Institute of Oceanography IEO, Vía Espaldón, Parcela 8, Santa Cruz De Tenerife, 38180, Spain
| | - Begoña Ayo
- Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of Basque Country (UPV/EHU), Sarriena S/N, Leioa, 48940, Spain.,Research Centre for Experimental Marine Biology and Biotechnology PiE-UPV/EHU, Areatza Hiribidea 47, Plentzia, 48620, Spain
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17
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Tittel J, Hüls M, Koschorreck M. Terrestrial Vegetation Drives Methane Production in the Sediments of two German Reservoirs. Sci Rep 2019; 9:15944. [PMID: 31685881 PMCID: PMC6828770 DOI: 10.1038/s41598-019-52288-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/12/2019] [Indexed: 11/21/2022] Open
Abstract
Inland waters and reservoirs in particular are significant sources of methane to the atmosphere. However, little information is available on the extent to which organic carbon from terrestrial vegetation or from internal photosynthesis fuels the methane production. This limits our ability to constrain methane emissions efficiently. We studied the isotopic composition (13C, 14C) of pelagic and sedimentary carbon sources in two small German reservoirs. The methane was enriched by radiocarbon with isotopic ranges (∆14C 5‰ to 31‰) near to fresh terrestrial organic carbon (OC, 17‰ to 26‰). In contrast, potential source OC produced by internal photosynthesis was characterized by negative ∆14C values (-30‰ and -25‰) as derived from signatures of inorganic carbon in the reservoirs. The particulate OC in stream supplies (terrestrial OC) was also 14C depleted in almost all cases, but highly variable in ∆14C (-131‰ to 42‰). Although the import of terrestrial OC was lower than the amount of OC produced by reservoir-internal photosynthesis, we conclude that the methane production was predominantly fuelled by catchment vegetation. The utilized terrestrial OC was of contemporary origin, fixed within years to decades before sampling and supplemented with reservoir-internal or aged terrestrial OC. Our results indicate that terrestrial biomass is an important driver of methane production in reservoirs receiving significant imports of terrestrial OC.
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Affiliation(s)
- Jörg Tittel
- Helmholtz Centre for Environmental Research - UFZ, Department Lake Research, Brückstraße 3a, D-39114, Magdeburg, Germany.
| | - Matthias Hüls
- Leibniz-Laboratory for Radiometric Dating and Stable Isotope Research, Max-Eyth-Str. 11-13, D-24118, Kiel, Germany
| | - Matthias Koschorreck
- Helmholtz Centre for Environmental Research - UFZ, Department Lake Research, Brückstraße 3a, D-39114, Magdeburg, Germany
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18
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Yan YW, Yang HC, Tang L, Li J, Mao YX, Mo ZL. Compositional Shifts of Bacterial Communities Associated With Pyropia yezoensis and Surrounding Seawater Co-occurring With Red Rot Disease. Front Microbiol 2019; 10:1666. [PMID: 31396184 PMCID: PMC6664831 DOI: 10.3389/fmicb.2019.01666] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 07/04/2019] [Indexed: 12/31/2022] Open
Abstract
Pyropia yezoensis is commercially the most important edible red alga in China, and red rot disease is viewed as one of the major constraints for its cultivation. Microbes within the oomycetic genus Pythium have been reported as the causative agents for this disease; however, little is known about the interactions between the disease and the epiphytic and planktonic bacterial communities. In the present study, bacterial communities associated with uninfected, locally infected, and seriously infected thalli collected from cultivation farms, and within seawater adjacent to the thalli, were investigated using in-depth 16S ribosomal RNA (rRNA) gene sequencing in conjunction with assessing multiple environmental factors. For both thalli and seawater, uninfected and infected communities were significantly different though alpha diversity was similar. Phylogenetic differences between epiphytic bacterial communities associated with P. yezoensis were mainly reflected by the relative changes in the dominant operational taxonomic units (OTUs) assigned as genus Flavirhabdus, genus Sulfitobacter, and family Rhodobacteraceae. The prevalent OTUs in seawater also differed in relative abundance across the communities and were affiliated with diverse taxa, including the phyla Actinobacteria, Verrucomicrobia, and Bacteroidetes, and the classes Alpha- and Gamma-proteobacteria. The differentiation of bacterial communities associated with P. yezoensis and seawater was primarily shaped by reactive silicate (RS) content and salinity, respectively. In particular, 14 potential indicators (two OTUs on P. yezoensis and twelve OTUs in seawater) were identified that significantly differentiated P. yezoensis health statuses and correlated with environmental changes. Overall, the present study provides insights into the alterations of bacterial communities associated with P. yezoensis and surrounding seawater co-occurring with red rot disease. Observed changes were closely associated with health status of algal host, and highlight the potential of using community differentiation to forecast disease occurrence.
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Affiliation(s)
- Yong-Wei Yan
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Hui-Chao Yang
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China.,College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Lei Tang
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jie Li
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Yun-Xiang Mao
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhao-Lan Mo
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China.,College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
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19
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Ávila MP, Brandão LPM, Brighenti LS, Tonetta D, Reis MP, Stæhr PA, Asmala E, Amado AM, Barbosa FAR, Bezerra-Neto JF, Nascimento AMA. Linking shifts in bacterial community with changes in dissolved organic matter pool in a tropical lake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 672:990-1003. [PMID: 30981171 DOI: 10.1016/j.scitotenv.2019.04.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/15/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Bacterioplankton communities have a pivotal role in the global carbon cycle. Still the interaction between microbial community and dissolved organic matter (DOM) in freshwater ecosystems remains poorly understood. Here, we report results from a 12-day mesocosm study performed in the epilimnion of a tropical lake, in which inorganic nutrients and allochthonous DOM were supplemented under full light and shading. Although the production of autochthonous DOM triggered by nutrient addition was the dominant driver of changes in bacterial community structure, temporal covariations between DOM optical proxies and bacterial community structure revealed a strong influence of community shifts on DOM fate. Community shifts were coupled to a successional stepwise alteration of the DOM pool, with different fractions being selectively consumed by specific taxa. Typical freshwater clades as Limnohabitans and Sporichthyaceae were associated with consumption of low molecular weight carbon, whereas Gammaproteobacteria and Flavobacteria utilized higher molecular weight carbon, indicating differences in DOM preference among clades. Importantly, Verrucomicrobiaceae were important in the turnover of freshly produced autochthonous DOM, ultimately affecting light availability and dissolved organic carbon concentrations. Our findings suggest that taxonomically defined bacterial assemblages play definite roles when influencing DOM fate, either by changing specific fractions of the DOM pool or by regulating light availability and DOC levels.
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Affiliation(s)
- Marcelo P Ávila
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Luciana P M Brandão
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Ludmila S Brighenti
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Denise Tonetta
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Mariana P Reis
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil.
| | - Peter A Stæhr
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, Box 358, 4000 Roskilde, Denmark
| | - Eero Asmala
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, Box 358, 4000 Roskilde, Denmark; Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland
| | - André M Amado
- Limnology Laboratory, Department of Oceanography and Limnology, Universidade Federal do Rio Grande do Norte, Rio Grande do Norte, Brazil
| | - Francisco A R Barbosa
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - José F Bezerra-Neto
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Andréa M A Nascimento
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil.
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20
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Xiao F, Bi Y, Li X, Huang J, Yu Y, Xie Z, Fang T, Cao X, He Z, Juneau P, Yan Q. The Impact of Anthropogenic Disturbance on Bacterioplankton Communities During the Construction of Donghu Tunnel (Wuhan, China). MICROBIAL ECOLOGY 2019; 77:277-287. [PMID: 29951743 DOI: 10.1007/s00248-018-1222-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Bacterioplankton are both primary producers and primary consumers in aquatic ecosystems, which were commonly investigated to reflect environmental changes, evaluate primary productivity, and assess biogeochemical cycles. However, there is relatively less understanding of their responses to anthropogenic disturbances such as constructions of dams/tunnels/roads that may significantly affect the aquatic ecosystem. To fill such gap, this study focused on the bacterioplankton communities' diversity and turnover during a tunnel construction across an urban lake (Lake Donghu, Wuhan, China), and five batches of samples were collected within 2 months according to the tunnel construction progress. Results indicated that both resources and predator factors contributed significant to the variations of bacterioplankton communities, but the closed area and open areas showed different diversity patterns due to the impacts of tunnel construction. Briefly, the phytoplankton, TN, and TP in water were still significantly correlated with the bacterioplankton composition and diversity like that in normal conditions. Additionally, the organic matter, TN, and NH4-N in sediments also showed clear effects on the bacterioplankton. However, the predator effects on the bacterioplankton in the closed-off construction area mainly derived from large zooplankton (i.e., cladocerans), while small zooplankton such as protozoa and rotifers are only responsible for weak predator effects on the bacterioplankton in the open areas. Further analysis about the ecological driving forces indicated that the bacterioplankton communities' turnover during the tunnel construction was mainly governed by the homogeneous selection due to similar environments within the closed area or the open areas at two different stages. This finding suggests that bacterioplankton communities can quickly adapt to the environmental modifications resulting from tunnel construction activities. This study can also give references to enhance our understanding on bacterioplankton communities' response to ecological and environmental changes due to intensification of construction and urbanization in and around lake ecosystems.
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Affiliation(s)
- Fanshu Xiao
- Environmental Microbiomics Research Center, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, and the School of Environmental Science and Engineering, Sun Yat-sen University, 132 East Circle, University Town, Guangzhou, 510006, China
| | - Yonghong Bi
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Xinghao Li
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Jie Huang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yuhe Yu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Zhicai Xie
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Tao Fang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Xiuyun Cao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Zhili He
- Environmental Microbiomics Research Center, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, and the School of Environmental Science and Engineering, Sun Yat-sen University, 132 East Circle, University Town, Guangzhou, 510006, China
| | - Philippe Juneau
- Département des Sciences biologiques - GRIL - TOXEN, Laboratory of Aquatic Microorganism Ecotoxicology, Université du Québec à Montréal, Succ. Centre-Ville, C.P. 8888, Montréal, Québec, H3C 3P8, Canada
| | - Qingyun Yan
- Environmental Microbiomics Research Center, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, and the School of Environmental Science and Engineering, Sun Yat-sen University, 132 East Circle, University Town, Guangzhou, 510006, China.
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21
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Fitch A, Orland C, Willer D, Emilson EJS, Tanentzap AJ. Feasting on terrestrial organic matter: Dining in a dark lake changes microbial decomposition. GLOBAL CHANGE BIOLOGY 2018; 24:5110-5122. [PMID: 29998600 PMCID: PMC6220883 DOI: 10.1111/gcb.14391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/30/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Boreal lakes are major components of the global carbon cycle, partly because of sediment-bound heterotrophic microorganisms that decompose within-lake and terrestrially derived organic matter (t-OM). The ability for sediment bacteria to break down and alter t-OM may depend on environmental characteristics and community composition. However, the connection between these two potential drivers of decomposition is poorly understood. We tested how bacterial activity changed along experimental gradients in the quality and quantity of t-OM inputs into littoral sediments of two small boreal lakes, a dark and a clear lake, and measured the abundance of operational taxonomic units and functional genes to identify mechanisms underlying bacterial responses. We found that bacterial production (BP) decreased across lakes with aromatic dissolved organic matter (DOM) in sediment pore water, but the process underlying this pattern differed between lakes. Bacteria in the dark lake invested in the energetically costly production of extracellular enzymes as aromatic DOM increased in availability in the sediments. By contrast, bacteria in the clear lake may have lacked the nutrients and/or genetic potential to degrade aromatic DOM and instead mineralized photo-degraded OM into CO2 . The two lakes differed in community composition, with concentrations of dissolved organic carbon and pH differentiating microbial assemblages. Furthermore, functional genes relating to t-OM degradation were relatively higher in the dark lake. Our results suggest that future changes in t-OM inputs to lake sediments will have different effects on carbon cycling depending on the potential for photo-degradation of OM and composition of resident bacterial communities.
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Affiliation(s)
- Amelia Fitch
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
| | - Chloe Orland
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
| | - David Willer
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
| | - Erik J. S. Emilson
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
- Natural Resources Canada, Great Lakes Forestry CentreSault Ste. MarieOntario
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22
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Ruiz-González C, Archambault E, Laforest-Lapointe I, del Giorgio PA, Kembel SW, Messier C, Nock CA, Beisner BE. Soils associated to different tree communities do not elicit predictable responses in lake bacterial community structure and function. FEMS Microbiol Ecol 2018; 94:5037915. [DOI: 10.1093/femsec/fiy115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 06/14/2018] [Indexed: 01/09/2023] Open
Affiliation(s)
- Clara Ruiz-González
- Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain
- Department of Biological Sciences, University of Québec at Montréal, Montréal, Canada
| | - Esther Archambault
- Department of Biological Sciences, University of Québec at Montréal, Montréal, Canada
| | | | - Paul A del Giorgio
- Department of Biological Sciences, University of Québec at Montréal, Montréal, Canada
| | - Steven W Kembel
- Department of Biological Sciences, University of Québec at Montréal, Montréal, Canada
| | - Christian Messier
- Department of Biological Sciences, University of Québec at Montréal, Montréal, Canada
| | - Charles A Nock
- Geobotany, Faculty of Biology, University of Freiburg, Germany
| | - Beatrix E Beisner
- Department of Biological Sciences, University of Québec at Montréal, Montréal, Canada
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23
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Taube R, Ganzert L, Grossart HP, Gleixner G, Premke K. Organic matter quality structures benthic fatty acid patterns and the abundance of fungi and bacteria in temperate lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 610-611:469-481. [PMID: 28818662 DOI: 10.1016/j.scitotenv.2017.07.256] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/27/2017] [Accepted: 07/29/2017] [Indexed: 05/25/2023]
Abstract
Benthic microbial communities (BMCs) play important roles in the carbon cycle of lakes, and benthic littoral zones in particular have been previously highlighted as biogeochemical hotspots. Dissolved organic matter (DOM) presents the major carbon pool in lakes, and although the effect of DOM composition on the pelagic microbial community composition is widely accepted, little is known about its effect on BMCs, particularly aquatic fungi. Therefore, we investigated the composition of benthic littoral microbial communities in twenty highly diverse lakes in northeast Germany. DOM quality was analyzed via size exclusion chromatography (SEC), fluorescence parallel factor analyses (PRAFACs) and UV-Vis spectroscopy. We determined the BMC composition and biomass using phospholipid-derived fatty acids (PLFA) and extended the interpretation to the analysis of fungi by applying a Bayesian mixed model. We present evidence that the quality of DOM structures the BMCs, which are dominated by heterotrophic bacteria and show low fungal biomass. The fungal biomass increases when the DOM pool is processed by microorganisms of allochthonous origin, whereas the opposite is true for bacteria.
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Affiliation(s)
- Robert Taube
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Dept. Chemical Analytics and Biogeochemistry, 12587 Berlin, Germany; Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Biogeochemistry, 15374 Müncheberg, Germany.
| | - Lars Ganzert
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Dept. Experimental Limnology, 16775 Stechlin, Germany
| | - Hans-Peter Grossart
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Dept. Experimental Limnology, 16775 Stechlin, Germany; Potsdam University, Institute for Biochemistry and Biology, 14469 Potsdam, Germany
| | - Gerd Gleixner
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Katrin Premke
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Dept. Chemical Analytics and Biogeochemistry, 12587 Berlin, Germany; Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Biogeochemistry, 15374 Müncheberg, Germany
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24
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Deng YJ, Wang SY. Complex carbohydrates reduce the frequency of antagonistic interactions among bacteria degrading cellulose and xylan. FEMS Microbiol Lett 2017; 364:fnx019. [PMID: 28130369 DOI: 10.1093/femsle/fnx019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 01/24/2017] [Indexed: 11/14/2022] Open
Abstract
Bacterial competition for resources is common in nature but positive interactions among bacteria are also evident. We speculate that the structural complexity of substrate might play a role in mediating bacterial interactions. We tested the hypothesis that the frequency of antagonistic interactions among lignocellulolytic bacteria is reduced when complex polysaccharide is the main carbon source compared to when a simple sugar such as glucose is available. Results using all possible pairwise interactions among 35 bacteria isolated from salt marsh detritus showed that the frequency of antagonistic interactions was significantly lower on carboxymethyl cellulose (CMC)-xylan medium (7.8%) than on glucose medium (15.5%). The two interaction networks were also different in their structures. Although 75 antagonistic interactions occurred on both media, there were 115 that occurred only on glucose and 20 only on CMC-xylan, indicating that some antagonistic interactions were substrate specific. We also found that the frequency of antagonism differed among phylogenetic groups. Gammaproteobacteria and Bacillus sp. were the most antagonistic and they tended to antagonize Bacteroidetes and Actinobacteria, the most susceptible groups. Results from the study suggest that substrate complexity affects how bacteria interact and that bacterial interactions in a community are dynamic as nutrient conditions change.
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25
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Roiha T, Peura S, Cusson M, Rautio M. Allochthonous carbon is a major regulator to bacterial growth and community composition in subarctic freshwaters. Sci Rep 2016; 6:34456. [PMID: 27686416 PMCID: PMC5043279 DOI: 10.1038/srep34456] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 09/14/2016] [Indexed: 11/09/2022] Open
Abstract
In the subarctic region, climate warming and permafrost thaw are leading to emergence of ponds and to an increase in mobility of catchment carbon. As carbon of terrestrial origin is increasing in subarctic freshwaters the resource pool supporting their microbial communities and metabolism is changing, with consequences to overall aquatic productivity. By sampling different subarctic water bodies for a one complete year we show how terrestrial and algal carbon compounds vary in a range of freshwaters and how differential organic carbon quality is linked to bacterial metabolism and community composition. We show that terrestrial drainage and associated nutrients supported higher bacterial growth in ponds and river mouths that were influenced by fresh terrestrial carbon than in large lakes with carbon from algal production. Bacterial diversity, however, was lower at sites influenced by terrestrial carbon inputs. Bacterial community composition was highly variable among different water bodies and especially influenced by concentrations of dissolved organic carbon (DOC), fulvic acids, proteins and nutrients. Furthermore, a distinct preference was found for terrestrial vs. algal carbon among certain bacterial tribes. The results highlight the contribution of the numerous ponds to cycling of terrestrial carbon in the changing subarctic and arctic regions.
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Affiliation(s)
- Toni Roiha
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada
| | - Sari Peura
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
| | - Mathieu Cusson
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada
| | - Milla Rautio
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada.,Centre for Northern Studies (CEN), Laval University, Quebec City, Quebec, Canada.,Group for Interuniversity Research in Limnology and aquatic environment (GRIL), University of Montreal, Montreal, Quebec, Canada
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26
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Xue Q, Su X, Steinman AD, Cai Y, Zhao Y, Xie L. Accumulation of microcystins in a dominant Chironomid Larvae (Tanypus chinensis) of a large, shallow and eutrophic Chinese lake, Lake Taihu. Sci Rep 2016; 6:31097. [PMID: 27499175 PMCID: PMC4976359 DOI: 10.1038/srep31097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/13/2016] [Indexed: 11/25/2022] Open
Abstract
Although there have been numerous studies on microcystin (MC) accumulation in aquatic organisms recently, the bioaccumulation of MCs in relatively small sized organisms, as well as potential influencing factors, has been rarely studied. Thus, in this study, we investigated the bioaccumulation of three MC congeners (-LR, -RR and -YR) in the chironomid larvae of Tanypus chinensis (an excellent food source for certain fishes), the potential sources of these MCs, and potentially relevant environmental parameters over the course of one year in Lake Taihu, China. MC concentrations in T. chinensis varied temporally with highest concentrations during the warmest months (except August 2013) and very low concentrations during the remaining months. Among the three potential MC sources, only intracellular MCs were significantly and positively correlated with MCs in T. chinensis. Although MC concentrations in T. chinensis significantly correlated with a series of physicochemical parameters of water column, cyanobacteria species explained the most variability of MC accumulation, with the rest primarily explained by extraMC-LR. These results indicated that ingestion of MC-producing algae of cyanobacteria accounted for most of the MC that accumulated in T. chinensis. The high MC concentrations in T. chinensis may pose a potential health threat to humans through trophic transfer.
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Affiliation(s)
- Qingju Xue
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaomei Su
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Alan D Steinman
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
| | - Yongjiu Cai
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
| | - Yanyan Zhao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
| | - Liqiang Xie
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
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27
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Song L, Li L. Variations in Bacterial Community in a Temperate Lake Associated with an Agricultural Watershed. MICROBIAL ECOLOGY 2016; 72:277-286. [PMID: 27216530 DOI: 10.1007/s00248-016-0783-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/08/2016] [Indexed: 06/05/2023]
Abstract
Terrestrially derived carbon and nutrients are washed into lakes, providing nutritional drivers for both microbial heterotrophy and phototrophy. Changes in the quantity and diversity of carbon and nutrients exported from watersheds in response to alterations in long-term land use have led to a need for evaluation of the linkage between watershed-exported carbon and nutrients and bacterial community structure in watershed associated lakes. To learn more about these interactions, we investigated Muskrat Lake in Michigan, which has a well-defined moderately sized watershed dominated by agriculture. We measured the water chemistry, characterized the dissolved organic carbon, and determined the structure of the bacterial communities at the inlet and center of this lake (five depths per site) over the summer and fall of 2008. The lake had temporal and rain event-based fluctuations in water chemistry, as well as temporal and rain event-dependent shifts in bacterial communities as measured by terminal restriction fragment length polymorphism. Agricultural watershed inputs were observed in the lake during and after rain events. Terminal restriction fragment length polymorphism and 454 pyrosequencing of the bacterial communities indicated that there were differences over time and that the dominant phylotypes shifted between summer and late fall. Some populations (e.g., Polynucleobacter and Mycobacterium) increased during fall, while others (e.g., Gemmatimonas) diminished. Redundancy and partitioning analyses showed that water chemistry is highly correlated with variations in the bacterial community of the lake, which explained 34 % of the variations in the bacterial community. Dissolved organic carbon had the greatest effects on variations in the Muskrat Lake bacterial community (2 %). The results of this study provide information that will enable a better understanding of the interaction between the bacterial community of lakes and changes in chemical properties as a result of nutrient importation from the surrounding watershed.
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Affiliation(s)
- Liyan Song
- Environmental Microbiology and Ecology Research Center, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 401122, China.
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, 48824, USA.
| | - Lei Li
- Environmental Microbiology and Ecology Research Center, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 401122, China
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28
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He P, Li L, Liu J, Bai Y, Fang X. Diversity and distribution of catechol 2, 3-dioxygenase genes in surface sediments of the Bohai Sea. FEMS Microbiol Lett 2016; 363:fnw086. [DOI: 10.1093/femsle/fnw086] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2016] [Indexed: 11/14/2022] Open
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29
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Ricão Canelhas M, Eiler A, Bertilsson S. Are freshwater bacterioplankton indifferent to variable types of amino acid substrates? FEMS Microbiol Ecol 2016; 92:fiw005. [PMID: 26738554 DOI: 10.1093/femsec/fiw005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2016] [Indexed: 11/13/2022] Open
Abstract
A wide range of carbon compounds sustain bacterial activity and growth in freshwater ecosystems and the amount and quality of these substrates influence bacterial diversity and metabolic function. Biologically labile low-molecular-weight compounds, such as dissolved free amino acids, are particularly important substrates and can fuel as much as 20% of the total heterotrophic production. In this study, we show that extensive laboratory incubations with variable amino acids as substrates caused only minimal differences in bacterial growth rate, growth yield, quantitative amino acid usage, community composition and diversity. This was in marked contrast to incubations under dark or light regimes, where significant responses were observed in bacterial community composition and with higher diversity in the dark incubations. While a few individual taxa still responded to amendment with specific amino acids, our results suggest that compositional shifts in the specific supply of amino acids and possibly also other labile organic substrates have a minor impact on heterotrophic bacterioplankton communities, at least in nutrient rich lakes and compared to other prevailing environmental factors.
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Affiliation(s)
- Monica Ricão Canelhas
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, SE-75236, Uppsala, Sweden
| | - Alexander Eiler
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, SE-75236, Uppsala, Sweden
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, SE-75236, Uppsala, Sweden
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30
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Cuss C, Guéguen C. Characterizing the Labile Fraction of Dissolved Organic Matter in Leaf Leachates: Methods, Indicators, Structure, and Complexity. LABILE ORGANIC MATTER-CHEMICAL COMPOSITIONS, FUNCTION, AND SIGNIFICANCE IN SOIL AND THE ENVIRONMENT 2015. [DOI: 10.2136/sssaspecpub62.2014.0043] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- C.W. Cuss
- Environmental and Life Science Graduate Program; 1600 West Bank Drive Peterborough Ontario Canada K9J 7B8
| | - C. Guéguen
- Chemistry Dep.; Trent University; 1600 West Bank Drive Peterborough Ontario Canada K9J 7B8
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31
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Lehmann K, Singer A, Bowes MJ, Ings NL, Field D, Bell T. 16S rRNA assessment of the influence of shading on early-successional biofilms in experimental streams. FEMS Microbiol Ecol 2015; 91:fiv129. [PMID: 26499485 PMCID: PMC4657191 DOI: 10.1093/femsec/fiv129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/30/2022] Open
Abstract
Elevated nutrient levels can lead to excessive biofilm growth, but reducing nutrient pollution is often challenging. There is therefore interest in developing control measures for biofilm growth in nutrient-rich rivers that could act as complement to direct reductions in nutrient load. Shading of rivers is one option that can mitigate blooms, but few studies have experimentally examined the differences in biofilm communities grown under shaded and unshaded conditions. We investigated the assembly and diversity of biofilm communities using in situ mesocosms within the River Thames (UK). Biofilm composition was surveyed by 454 sequencing of 16S amplicons (∼400 bp length covering regions V6/V7). The results confirm the importance of sunlight for biofilm community assembly; a resource that was utilized by a relatively small number of dominant taxa, leading to significantly less diversity than in shaded communities. These differences between unshaded and shaded treatments were either because of differences in resource utilization or loss of diatom-structures as habitats for bacteria. We observed more co-occurrence patterns and network interactions in the shaded communities. This lends further support to the proposal that increased river shading can help mitigate the effects from macronutrient pollution in rivers. Riparian shading as a mitigation of harmful algal blooms leads to significant structural changes to both bacterial and algal communities in river biofilms.
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Affiliation(s)
- Katja Lehmann
- NERC Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK
| | - Andrew Singer
- NERC Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK
| | - Michael J Bowes
- NERC Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK
| | | | - Dawn Field
- NERC Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK
| | - Thomas Bell
- Imperial College London, Department of Life Sciences, Silwood Park Campus, SL5 7PY, UK
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32
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Lindh MV, Lefébure R, Degerman R, Lundin D, Andersson A, Pinhassi J. Consequences of increased terrestrial dissolved organic matter and temperature on bacterioplankton community composition during a Baltic Sea mesocosm experiment. AMBIO 2015; 44 Suppl 3:402-12. [PMID: 26022323 PMCID: PMC4447689 DOI: 10.1007/s13280-015-0659-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Predicted increases in runoff of terrestrial dissolved organic matter (DOM) and sea surface temperatures implicate substantial changes in energy fluxes of coastal marine ecosystems. Despite marine bacteria being critical drivers of marine carbon cycling, knowledge of compositional responses within bacterioplankton communities to such disturbances is strongly limited. Using 16S rRNA gene pyrosequencing, we examined bacterioplankton population dynamics in Baltic Sea mesocosms with treatments combining terrestrial DOM enrichment and increased temperature. Among the 200 most abundant taxa, 62 % either increased or decreased in relative abundance under changed environmental conditions. For example, SAR11 and SAR86 populations proliferated in combined increased terrestrial DOM/temperature mesocosms, while the hgcI and CL500-29 clades (Actinobacteria) decreased in the same mesocosms. Bacteroidetes increased in both control mesocosms and in the combined increased terrestrial DOM/temperature mesocosms. These results indicate considerable and differential responses among distinct bacterial populations to combined climate change effects, emphasizing the potential of such effects to induce shifts in ecosystem function and carbon cycling in the future Baltic Sea.
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Affiliation(s)
- Markus V. Lindh
- />Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Linnaeus University, 391 82 Kalmar, Sweden
| | - Robert Lefébure
- />Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden
- />Marine Stewardship Council, 1 Snow Hill, London, EC1A 2DH UK
| | - Rickard Degerman
- />Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden
| | - Daniel Lundin
- />Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Linnaeus University, 391 82 Kalmar, Sweden
| | - Agneta Andersson
- />Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden
| | - Jarone Pinhassi
- />Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Linnaeus University, 391 82 Kalmar, Sweden
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33
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Lindh MV, Figueroa D, Sjöstedt J, Baltar F, Lundin D, Andersson A, Legrand C, Pinhassi J. Transplant experiments uncover Baltic Sea basin-specific responses in bacterioplankton community composition and metabolic activities. Front Microbiol 2015; 6:223. [PMID: 25883589 PMCID: PMC4381636 DOI: 10.3389/fmicb.2015.00223] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/05/2015] [Indexed: 11/21/2022] Open
Abstract
Anthropogenically induced changes in precipitation are projected to generate increased river runoff to semi-enclosed seas, increasing loads of terrestrial dissolved organic matter and decreasing salinity. To determine how bacterial community structure and functioning adjust to such changes, we designed microcosm transplant experiments with Baltic Proper (salinity 7.2) and Bothnian Sea (salinity 3.6) water. Baltic Proper bacteria generally reached higher abundances than Bothnian Sea bacteria in both Baltic Proper and Bothnian Sea water, indicating higher adaptability. Moreover, Baltic Proper bacteria growing in Bothnian Sea water consistently showed highest bacterial production and beta-glucosidase activity. These metabolic responses were accompanied by basin-specific changes in bacterial community structure. For example, Baltic Proper Pseudomonas and Limnobacter populations increased markedly in relative abundance in Bothnian Sea water, indicating a replacement effect. In contrast, Roseobacter and Rheinheimera populations were stable or increased in abundance when challenged by either of the waters, indicating an adjustment effect. Transplants to Bothnian Sea water triggered the initial emergence of particular Burkholderiaceae populations, and transplants to Baltic Proper water triggered Alteromonadaceae populations. Notably, in the subsequent re-transplant experiment, a priming effect resulted in further increases to dominance of these populations. Correlated changes in community composition and metabolic activity were observed only in the transplant experiment and only at relatively high phylogenetic resolution. This suggested an importance of successional progression for interpreting relationships between bacterial community composition and functioning. We infer that priming effects on bacterial community structure by natural episodic events or climate change induced forcing could translate into long-term changes in bacterial ecosystem process rates.
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Affiliation(s)
- Markus V Lindh
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar Sweden
| | - Daniela Figueroa
- Department of Ecology and Environmental Science, Umeå University, Umeå Sweden ; Umeå Marine Sciences Centre, Umeå University, Umeå Sweden
| | - Johanna Sjöstedt
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar Sweden
| | - Federico Baltar
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar Sweden ; Department of Marine Science, University of Otago, Dunedin New Zealand
| | - Daniel Lundin
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar Sweden
| | - Agneta Andersson
- Department of Ecology and Environmental Science, Umeå University, Umeå Sweden ; Umeå Marine Sciences Centre, Umeå University, Umeå Sweden
| | - Catherine Legrand
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar Sweden
| | - Jarone Pinhassi
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar Sweden
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Crevecoeur S, Vincent WF, Comte J, Lovejoy C. Bacterial community structure across environmental gradients in permafrost thaw ponds: methanotroph-rich ecosystems. Front Microbiol 2015; 6:192. [PMID: 25926816 PMCID: PMC4396522 DOI: 10.3389/fmicb.2015.00192] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 02/20/2015] [Indexed: 11/15/2022] Open
Abstract
Permafrost thawing leads to the formation of thermokarst ponds that potentially emit CO2 and CH4 to the atmosphere. In the Nunavik subarctic region (northern Québec, Canada), these numerous, shallow ponds become well-stratified during summer. This creates a physico-chemical gradient of temperature and oxygen, with an upper oxic layer and a bottom low oxygen or anoxic layer. Our objective was to determine the influence of stratification and related limnological and landscape properties on the community structure of potentially active bacteria in these waters. Samples for RNA analysis were taken from ponds in three contrasting valleys across a gradient of permafrost degradation. A total of 1296 operational taxonomic units were identified by high throughput amplicon sequencing, targeting bacterial 16S rRNA that was reverse transcribed to cDNA. β-proteobacteria were the dominant group in all ponds, with highest representation by the genera Variovorax and Polynucleobacter. Methanotrophs were also among the most abundant sequences at most sites. They accounted for up to 27% of the total sequences (median of 4.9% for all samples), indicating the importance of methane as a bacterial energy source in these waters. Both oxygenic (cyanobacteria) and anoxygenic (Chlorobi) phototrophs were also well-represented, the latter in the low oxygen bottom waters. Ordination analyses showed that the communities clustered according to valley and depth, with significant effects attributed to dissolved oxygen, pH, dissolved organic carbon, and total suspended solids. These results indicate that the bacterial assemblages of permafrost thaw ponds are filtered by environmental gradients, and are complex consortia of functionally diverse taxa that likely affect the composition as well as magnitude of greenhouse gas emissions from these abundant waters.
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Affiliation(s)
- Sophie Crevecoeur
- Département de Biologie and Takuvik Joint International Laboratory, Université Laval Québec, QC, Canada ; Centre d'Études Nordiques, Université Laval Québec, QC, Canada ; Institut de Biologie Intégrative et des Systèmes, Université Laval Québec, QC, Canada
| | - Warwick F Vincent
- Département de Biologie and Takuvik Joint International Laboratory, Université Laval Québec, QC, Canada ; Centre d'Études Nordiques, Université Laval Québec, QC, Canada
| | - Jérôme Comte
- Département de Biologie and Takuvik Joint International Laboratory, Université Laval Québec, QC, Canada ; Centre d'Études Nordiques, Université Laval Québec, QC, Canada ; Institut de Biologie Intégrative et des Systèmes, Université Laval Québec, QC, Canada
| | - Connie Lovejoy
- Département de Biologie and Takuvik Joint International Laboratory, Université Laval Québec, QC, Canada ; Institut de Biologie Intégrative et des Systèmes, Université Laval Québec, QC, Canada ; Québec Océan, Université Laval Québec, QC, Canada
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Llirós M, Inceoğlu Ö, García-Armisen T, Anzil A, Leporcq B, Pigneur LM, Viroux L, Darchambeau F, Descy JP, Servais P. Bacterial community composition in three freshwater reservoirs of different alkalinity and trophic status. PLoS One 2014; 9:e116145. [PMID: 25541975 PMCID: PMC4277477 DOI: 10.1371/journal.pone.0116145] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/03/2014] [Indexed: 11/21/2022] Open
Abstract
In order to investigate the factors controlling the bacterial community composition (BCC) in reservoirs, we sampled three freshwater reservoirs with contrasted physical and chemical characteristics and trophic status. The BCC was analysed by 16S rRNA gene amplicon 454 pyrosequencing. In parallel, a complete dataset of environmental parameters and phytoplankton community composition was also collected. BCC in the analysed reservoirs resembled that of epilimnetic waters of natural freshwater lakes with presence of Actinobacteria, Alpha- and Betaproteobacteria, Cytophaga–Flavobacteria–Bacteroidetes (CFB) and Verrucomicrobia groups. Our results evidenced that the retrieved BCC in the analysed reservoirs was strongly influenced by pH, alkalinity and organic carbon content, whereas comparatively little change was observed among layers in stratified conditions.
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Affiliation(s)
- Marc Llirós
- Laboratory of Freshwater Ecology, University of Namur, Namur, Belgium
| | - Özgül Inceoğlu
- Ecologie des Systèmes Aquatiques, Université Libre de Bruxelles, Brussels, Belgium
| | | | - Adriana Anzil
- Ecologie des Systèmes Aquatiques, Université Libre de Bruxelles, Brussels, Belgium
| | - Bruno Leporcq
- Laboratory of Freshwater Ecology, University of Namur, Namur, Belgium
| | | | - Laurent Viroux
- Laboratory of Freshwater Ecology, University of Namur, Namur, Belgium
| | | | - Jean-Pierre Descy
- Laboratory of Freshwater Ecology, University of Namur, Namur, Belgium
| | - Pierre Servais
- Ecologie des Systèmes Aquatiques, Université Libre de Bruxelles, Brussels, Belgium
- * E-mail:
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Pang X, Shen H, Niu Y, Sun X, Chen J, Xie P. Dissolved organic carbon and relationship with bacterioplankton community composition in 3 lake regions of Lake Taihu, China. Can J Microbiol 2014; 60:669-80. [PMID: 25302531 DOI: 10.1139/cjm-2013-0847] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To clarify the relationships between dissolved organic carbon (DOC) and bacterioplankton community composition (BCC), a 1-year survey (June 2009 - May 2010) was conducted in 3 regions of Lake Taihu (Meiliang Bay, Lake Center, and Eastern Taihu), China. Polymerase chain reaction - denaturing gradient gel electrophoresis was used to analyze the composition and heterogeneity of the bacterioplankton community. Canonical correspondence analysis was used to explore the relationships between DOC concentration and BCC. We found a significant negative correlation between DOC concentration and bacterioplankton community diversity (as measured by the Shannon-Wiener index (H')). The results show that spatial variation in the bacterioplankton population was stronger than the seasonal variation and that DOC concentration influences BCC in Lake Taihu. DOC concentration, followed by macrophyte biomass, water turbidity, and phytoplankton biomass were the most influential factors that account for BCC changes in Lake Taihu. More detailed studies on the relationship between DOC concentration and BCC should focus on differences in DOC concentrations and quality among these lake regions. DOC had a significant impact on BCC in Meiliang Bay. The relationship between DOC and BCC in the 2 other regions studied (Lake Center and Eastern Taihu) was weaker. The results of this study add to our understanding of the BCC in eutrophic lakes, especially regarding the role of the microbial loop in lake ecosystems.
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Affiliation(s)
- Xinghong Pang
- a Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, People's Republic of China
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Miki T, Yokokawa T, Matsui K. Biodiversity and multifunctionality in a microbial community: a novel theoretical approach to quantify functional redundancy. Proc Biol Sci 2013; 281:20132498. [PMID: 24352945 PMCID: PMC3871314 DOI: 10.1098/rspb.2013.2498] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Ecosystems have a limited buffering capacity of multiple ecosystem functions against biodiversity loss (i.e. low multifunctional redundancy). We developed a novel theoretical approach to evaluate multifunctional redundancy in a microbial community using the microbial genome database (MBGD) for comparative analysis. In order to fully implement functional information, we defined orthologue richness in a community, each of which is a functionally conservative evolutionary unit in genomes, as an index of community multifunctionality (MF). We constructed a graph of expected orthologue richness in a community (MF) as a function of species richness (SR), fit the power function to SR (i.e. MF = cSRa), and interpreted the higher exponent a as the lower multifunctional redundancy. Through a microcosm experiment, we confirmed that MF defined by orthologue richness could predict the actual multiple functions. We simulated random and non-random community assemblages using full genomic data of 478 prokaryotic species in the MBGD, and determined that the exponent in microbial communities ranged from 0.55 to 0.75. This exponent range provided a quantitative estimate that a 6.6–8.9% loss limit in SR occurred in a microbial community for an MF reduction no greater than 5%, suggesting a non-negligible initial loss effect of microbial diversity on MF.
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Affiliation(s)
- Takeshi Miki
- Institute of Oceanography, National Taiwan University, , Number 1, Section 4 Roosevelt Road, Taipei 10617, Taiwan, Republic of China, Center for Marine Environmental Studies (CMES), Ehime University, , 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan, Laboratory of Environmental Biological Science, Faculty of Science and Technology, Kinki University, , 3-4-1 Kowakae Higashiosaka, Osaka 577-8502, Japan
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Massicotte P, Frenette JJ. A mechanistic-based framework to understand how dissolved organic carbon is processed in a large fluvial lake. ACTA ACUST UNITED AC 2013. [DOI: 10.1215/21573689-2372976] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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40
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Comte J, Fauteux L, Del Giorgio PA. Links between metabolic plasticity and functional redundancy in freshwater bacterioplankton communities. Front Microbiol 2013; 4:112. [PMID: 23675372 PMCID: PMC3650318 DOI: 10.3389/fmicb.2013.00112] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 04/18/2013] [Indexed: 12/01/2022] Open
Abstract
Metabolic plasticity and functional redundancy are fundamental properties of microbial communities, which shape their response to environmental forcing, and also mediate the relationship between community composition and function. Yet, the actual quantification of these emergent community properties has been elusive, and we thus do not know how they vary across bacterial communities, and their relationship to environmental gradients and to each other. Here we present an experimental framework that allows us to simultaneously quantify metabolic plasticity and functional redundancy in freshwater bacterioplankton communities, and to explore connections that may exists between them. We define metabolic plasticity as the rate of change in single-cell properties (cell wall integrity, cell size, single-cell activity) relative to changes in community composition. Likewise, we define functional redundancy as the rate of change in carbon substrate uptake capacities relative to changes in community composition. We assessed these two key community attributes in transplant experiments where bacterioplankton from various aquatic habitats within the same watershed were transplanted from their original water to waters from other systems that differ in their main resources. Our results show that metabolic plasticity is an intrinsic property of bacterial communities, whereas the expression of functional redundancy appears to be more dependent on environmental factors. Furthermore, there was an overall strong positive relationship between the level of functional redundancy and of metabolic plasticity, suggesting no trade-offs between these community attributes but rather a possible co-selection. The apparent continuum in the expression of both functional redundancy and plasticity among bacterial communities and the link between them, in turn suggest that the link between community diversity and function may also vary along a continuum, from being very tight, to being weak, or absent.
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Affiliation(s)
- Jérôme Comte
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal Montréal, QC, Canada ; Département de Biologie, Centre d'Études Nordiques, Unité Mixte Internationale Takuvik, Institut de Biologie Intégrative et des Systèmes, Université Laval QC, Canada
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41
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Llames ME, Del Giorgio PA, Zagarese H, Ferraro M, Izaguirre I. Alternative states drive the patterns in the bacterioplankton composition in shallow Pampean lakes (Argentina). ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:310-321. [PMID: 23584972 DOI: 10.1111/1758-2229.12020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 10/12/2012] [Accepted: 11/22/2012] [Indexed: 06/02/2023]
Abstract
We assessed the influence of environmental factors in shaping the free-living bacterial community structure in a set of shallow lakes characterized by contrasting stable state patterns (clear-vegetated, inorganic-turbid and phytoplankton-turbid). Six temperate shallow lakes from the Pampa Plain (Argentina) were sampled over an annual cycle, and two fingerprinting techniques were applied: a 16S rDNA analysis was performed using denaturing gradient gel electrophoresis (DGGE) profiles, and a 16S-23S internally transcribed spacer region analysis was conducted by means of automated ribosomal intergenic spacer analysis (ARISA) profiles. Our results show that the steady state that characterized the different shallow lakes played a major role in structuring the community: the composition of free-living bacteria differed significantly between clear-vegetated, inorganic-turbid and phytoplankton-turbid shallow lakes. The state of the system was more important in determining these patterns than seasonality, geographical location or degree of hydrological connectivity. Moreover, this strong environmental control was particularly evident in the pattern observed in one of the lakes, which shifted from a clear to a turbid state over the course of the study. This lake showed a directional selection of species from a typical clear-like to a turbid-like community. The combined DGGE/ARISA approach revealed not only broad patterns among different alternative steady states, but also more subtle differences within different regimes.
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Affiliation(s)
- Maria E Llames
- Laboratorio de Ecología y Fotobiología Acuática, Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico Chascomús, CONICET, UNSAM, Camino de Circunvalación Laguna Km 8, Chascomús, pcia. de Buenos Aires, Argentina, CP (B 7130 IWA).
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Ylla I, Peter H, Romaní AM, Tranvik LJ. Different diversity-functioning relationship in lake and stream bacterial communities. FEMS Microbiol Ecol 2013; 85:95-103. [DOI: 10.1111/1574-6941.12101] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 02/08/2013] [Accepted: 02/21/2013] [Indexed: 11/26/2022] Open
Affiliation(s)
- Irene Ylla
- Institute of Aquatic Ecology; University of Girona; Girona; Spain
| | | | - Anna M. Romaní
- Institute of Aquatic Ecology; University of Girona; Girona; Spain
| | - Lars J. Tranvik
- Department of Ecology and Genetics, Limnology; Uppsala University; Uppsala; Sweden
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Horemans B, Vandermaesen J, Smolders E, Springael D. Cooperative dissolved organic carbon assimilation by a linuron-degrading bacterial consortium. FEMS Microbiol Ecol 2012; 84:35-46. [DOI: 10.1111/1574-6941.12036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 10/11/2012] [Accepted: 10/14/2012] [Indexed: 11/28/2022] Open
Affiliation(s)
- Benjamin Horemans
- Division of Soil and Water Management; Department of Earth and Environmental Sciences; Faculty of Bioscience Engineering; KU Leuven; Leuven; Belgium
| | - Johanna Vandermaesen
- Division of Soil and Water Management; Department of Earth and Environmental Sciences; Faculty of Bioscience Engineering; KU Leuven; Leuven; Belgium
| | - Erik Smolders
- Division of Soil and Water Management; Department of Earth and Environmental Sciences; Faculty of Bioscience Engineering; KU Leuven; Leuven; Belgium
| | - Dirk Springael
- Division of Soil and Water Management; Department of Earth and Environmental Sciences; Faculty of Bioscience Engineering; KU Leuven; Leuven; Belgium
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Paver SF, Nelson CE, Kent AD. Temporal succession of putative glycolate-utilizing bacterioplankton tracks changes in dissolved organic matter in a high-elevation lake. FEMS Microbiol Ecol 2012; 83:541-51. [DOI: 10.1111/1574-6941.12012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 09/10/2012] [Accepted: 09/11/2012] [Indexed: 11/29/2022] Open
Affiliation(s)
- Sara F. Paver
- Program in Ecology, Evolution, and Conservation Biology; University of Illinois; Urbana; IL; USA
| | - Craig E. Nelson
- Marine Science Institute; University of California; Santa Barbara; CA; USA
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Sintes E, Witte H, Stodderegger K, Steiner P, Herndl GJ. Temporal dynamics in the free-living bacterial community composition in the coastal North Sea. FEMS Microbiol Ecol 2012; 83:413-24. [PMID: 22938648 PMCID: PMC3561708 DOI: 10.1111/1574-6941.12003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 06/06/2012] [Accepted: 08/22/2012] [Indexed: 11/29/2022] Open
Abstract
The coastal North Sea is characterized by strong seasonal dynamics in abiotic and biotic variables. Hence, pronounced temporal changes in the bacterioplankton community composition can be expected. Catalyzed reporter deposition fluorescence in situ hybridization analysis showed a seasonal succession, with Alphaproteobacteria dominating before the spring phytoplankton bloom, Bacteroidetes increasing during the bloom (up to 60% of the prokaryotic community) and being replaced by Gammaproteobacteria during the postbloom period (on average 30% of prokaryotic cells). Daily changes in similarity of the bacterioplankton community assessed by Terminal Restriction Fragment Length Polymorphism averaged 0.08 day−1 (Whittaker similarity index) for the free-living bacterial community, resulting in a decreasing similarity between samples with increasing time up to approximately 150 days. After about 150 days, the community composition became increasingly similar to the initial composition. Changes in the bacterial community showed periods of fairly stable composition, interrupted by periods of rapid changes. Taken together, our results support the notion of a recurring bacterioplankton community in the coastal North Sea and indicate a tight coupling between the resources, the bacterial community metabolism, physiological structure and community composition throughout the seasonal cycle in the coastal North Sea.
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Affiliation(s)
- Eva Sintes
- Department of Biological Oceanography, Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands.
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46
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Jones SE, Cadkin TA, Newton RJ, McMahon KD. Spatial and temporal scales of aquatic bacterial beta diversity. Front Microbiol 2012; 3:318. [PMID: 22969757 PMCID: PMC3431545 DOI: 10.3389/fmicb.2012.00318] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 08/14/2012] [Indexed: 11/15/2022] Open
Abstract
Understanding characteristic variation in aquatic bacterial community composition (BCC) across space and time can inform us about processes driving community assembly and the ability of bacterial communities to respond to perturbations. In this study, we synthesize BCC data from north temperate lakes to evaluate our current understanding of how BCC varies across multiple scales in time and space. A hierarchy of average similarity emerged with the highest similarity found among samples collected within the same lake, especially within the same basin, followed by similarity among samples collected through time within the same lake, and finally similarity among samples collected from different lakes. Using decay of similarity across time and space, we identified equivalent temporal (1 day) and spatial (10 m) scales of BCC variation. Finally, we identify an intriguing pattern of contrasting patterns of intra- and inter-annual BCC variation in two lakes. We argue our synthesis of spatio-temporal variation of aquatic BCC informs expectations for the response of aquatic bacterial communities to perturbation and environmental change. However, further long-term temporal observations will be needed to develop a general understanding of inter-annual BCC variation and our ability to use aquatic BCC as a sensitive metric of environmental change.
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Affiliation(s)
- Stuart E Jones
- Department of Biological Sciences, University of Notre Dame Notre Dame, IN, USA
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Steven B, McCann S, Ward NL. Pyrosequencing of plastid 23S rRNA genes reveals diverse and dynamic cyanobacterial and algal populations in two eutrophic lakes. FEMS Microbiol Ecol 2012; 82:607-15. [DOI: 10.1111/j.1574-6941.2012.01429.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 05/24/2012] [Accepted: 06/06/2012] [Indexed: 11/26/2022] Open
Affiliation(s)
- Blaire Steven
- Department of Molecular Biology; University of Wyoming; Laramie; WY; USA
| | - Sage McCann
- Department of Molecular Biology; University of Wyoming; Laramie; WY; USA
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Lindström ES, Langenheder S. Local and regional factors influencing bacterial community assembly. ENVIRONMENTAL MICROBIOLOGY REPORTS 2012; 4:1-9. [PMID: 23757223 DOI: 10.1111/j.1758-2229.2011.00257.x] [Citation(s) in RCA: 260] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The classical view states that microbial biogeography is not affected by dispersal barriers or historical events, but only influenced by the local contemporary habitat conditions (species sorting). This has been challenged during recent years by studies suggesting that also regional factors such as mass effect, dispersal limitation and neutral assembly are important for the composition of local bacterial communities. Here we summarize results from biogeography studies in different environments, i.e. in marine, freshwater and soil as well in human hosts. Species sorting appears to be the most important mechanism. However, this result might be biased since this is the mechanism that is easiest to measure, detect and interpret. Hence, the importance of regional factors may have been underestimated. Moreover, our survey indicates that different assembly mechanisms might be important for different parts of the total community, differing, for example, between generalists and specialists, and between taxa of different dispersal ability and motility. We conclude that there is a clear need for experimental studies, first, to clearly separate regional and local factors in order to study their relative importance, and second, to test whether there are differences in assembly mechanisms depending on different taxonomic or functional groups.
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Affiliation(s)
- Eva S Lindström
- Limnology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18 D, 752 36 Uppsala, Sweden
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Frossard A, Gerull L, Mutz M, Gessner MO. Disconnect of microbial structure and function: enzyme activities and bacterial communities in nascent stream corridors. ISME JOURNAL 2011; 6:680-91. [PMID: 22030674 DOI: 10.1038/ismej.2011.134] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A fundamental issue in microbial and general ecology is the question to what extent environmental conditions dictate the structure of communities and the linkages with functional properties of ecosystems (that is, ecosystem function). We approached this question by taking advantage of environmental gradients established in soil and sediments of small stream corridors in a recently created, early successional catchment. Specifically, we determined spatial and temporal patterns of bacterial community structure and their linkages with potential microbial enzyme activities along the hydrological flow paths of the catchment. Soil and sediments were sampled in a total of 15 sites on four occasions spread throughout a year. Denaturing gradient gel electrophoresis (DGGE) was used to characterize bacterial communities, and substrate analogs linked to fluorescent molecules served to track 10 different enzymes as specific measures of ecosystem function. Potential enzyme activities varied little among sites, despite contrasting environmental conditions, especially in terms of water availability. Temporal changes, in contrast, were pronounced and remarkably variable among the enzymes tested. This suggests much greater importance of temporal dynamics than spatial heterogeneity in affecting specific ecosystem functions. Most strikingly, bacterial community structure revealed neither temporal nor spatial patterns. The resulting disconnect between bacterial community structure and potential enzyme activities indicates high functional redundancy within microbial communities even in the physically and biologically simplified stream corridors of early successional landscapes.
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Affiliation(s)
- Aline Frossard
- Department of Aquatic Ecology, Eawag (Swiss Federal Institute of Aquatic Science and Technology), Dübendorf, Switzerland.
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50
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Massicotte P, Frenette JJ. Spatial connectivity in a large river system: resolving the sources and fate of dissolved organic matter. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2011; 21:2600-2617. [PMID: 22073647 DOI: 10.1890/10-1475.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Large rivers are generally heterogeneous and productive systems that receive important inputs of dissolved organic matter (DOM) from terrestrial and in situ sources. Thus, they are likely to play a significant role in the biogeochemical cycling of the DOM flowing to the oceans. The asymmetric spatial gradient driven by directional flow and environmental heterogeneity contributes to the fate of DOM flowing downstream. Yet, the relative effects of spatial connectivity and environmental heterogeneity on DOM dynamics are poorly understood. For example, since environmental variables show spatial heterogeneity, the variation explained by environmental and spatial variables may be redundant. We used the St. Lawrence River (SLR) as a representative large river to resolve the unique influences of environmental heterogeneity and spatial connectivity on DOM dynamics. We used three-dimensional fluorescence matrices combined with parallel factor analysis (PARAFAC) to characterize the DOM pool in the SLR. Seven fluorophores were modeled, of which two were identified to be of terrestrial origin and three from algal exudates. We measured a set of environmental variables that are known to drive the fate of DOM in aquatic systems. Additionally, we used asymmetric eigenvector map (AEM) modeling to take spatial connectivity into account. The combination of spatial and environmental models explained 85% of the DOM variation. We show that spatial connectivity is an important driver of DOM dynamics, as a large fraction of environmental heterogeneity was attributable to the asymmetric spatial gradient. Along the longitudinal axis, we noted a rapid increase in dissolved organic carbon (DOC), mostly controlled by terrestrial input of DOM originating from the tributaries. Variance partitioning demonstrated that freshly produced protein-like DOM was found to be the preferential substrate for heterotrophic bacteria undergoing rapid proliferation, while humic-like DOM was more correlated to the diffuse attenuation coefficient of UVA radiation.
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Affiliation(s)
- Philippe Massicotte
- Université du Québec à Trois-Rivières, Département de Chimie-Biologie, C.P. 500, Trois-Rivières, Québec G9A 5H7, Canada
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