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Kivistik C, Käiro K, Tammert H, Sokolova IM, Kisand V, Herlemann DPR. Distinct stages of the intestinal bacterial community of Ampullaceana balthica after salinization. Front Microbiol 2022; 13:767334. [PMID: 36110301 PMCID: PMC9468257 DOI: 10.3389/fmicb.2022.767334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 07/19/2022] [Indexed: 12/15/2022] Open
Abstract
Environmental disturbances influence bacterial community structure and functioning. To investigate the effect of environmental disturbance caused by changes in salinity on host-protected bacterial communities, we analyzed the microbiome within the gastrointestinal tract of Ampullaceana balthica in different salinities. A. balthica is a benthic gastropod found in fresh- and mesohaline waters. Whereas the total energy reserves of A. balthica were unaffected by an increase of salinity to 3, a high mortality rate was detected after a shift from freshwater to salinity 6 suggesting a major disruption of energy homeostasis. The shift to salinity 6 also caused a change in the gastrointestinal bacterial community composition. At salinity 3, the bacterial community composition of different host individuals was related either to the freshwater or salinity 6 gastrointestinal bacterial community, indicating an ambivalent nature of salinity 3. Since salinity 3 represents the range where aquatic gastropods are able to regulate their osmolarity, this may be an important tipping point during salinization. The change in the intestinal microbiome was uncoupled from the change in the water bacterial community and unrelated to the food source microbiome. Our study shows that environmental disturbance caused by salinity acts also on the host-protected microbiome. In light of the sea-level rise, our findings indicate that salinization of the near-shore freshwater bodies will cause changes in organisms' intestinal microbiomes if a critical salinity threshold (presumably ∼3) is exceeded.
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Affiliation(s)
- Carmen Kivistik
- Estonian University of Life Sciences, Center for Limnology, Tartu, Estonia
| | - Kairi Käiro
- Estonian University of Life Sciences, Center for Limnology, Tartu, Estonia
| | - Helen Tammert
- Estonian University of Life Sciences, Center for Limnology, Tartu, Estonia
| | - Inna M. Sokolova
- Department of Marine Biology, Institute for Biological Sciences, University of Rostock, Rostock, Germany
- Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Veljo Kisand
- Estonian University of Life Sciences, Center for Limnology, Tartu, Estonia
- Institute of Technology, University of Tartu, Tartu, Estonia
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Xiao X, Powers LC, Liu J, Gonsior M, Zhang R, Zhang L, MacIntyre HL, Chen X, Hu C, Batt J, Shi Q, Xu D, Zhang Y, Jiao N. Biodegradation of Terrigenous Organic Matter in a Stratified Large-Volume Water Column: Implications of the Removal of Terrigenous Organic Matter in the Coastal Ocean. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5234-5246. [PMID: 35357815 DOI: 10.1021/acs.est.1c08317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Large amounts of terrigenous organic matter (TOM) are delivered to the ocean every year. However, removal processes of TOM in the ocean are still poorly constrained. Here, we report results from a 339-day dark incubation experiment with a unique system holding a vertically stratified freshwater-seawater column. The quality and quantity of dissolved organic matter (DOM), RNA-based size-fraction microbial communities, and environmental factors were high-frequency-monitored. Microbial processes impacted TOM composition, including an increased DOM photobleaching rate with incubation time. The mixed layer had changed the bacterial community structure, diversity, and higher oxygen consumption rate. A two-end member modeling analysis suggested that estimated nutrient concentrations and prokaryotic abundance were lower, and total dissolved organic carbon was higher than that of the measured values. These results imply that DOM biodegradation was stimulated during freshwater-seawater mixing. In the bottom layer, fluorescent DOM components increased with the incubation time and were significantly positively related to highly unsaturated, oxygenated, and presumably aromatic compound molecular formulas. These results suggest that surfaced-derived TOM sinking leads to increased DOM transformation and likely results in carbon storage in the bottom water. Overall, these results suggest that microbial transforming TOM plays more important biogeochemical roles in estuaries and coastal oceans than what we know before.
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Affiliation(s)
- Xilin Xiao
- College of the Environment and Ecology, Xiamen University, Xiamen361102, China
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Leanne C Powers
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, Maryland20688, United States
| | - Jihua Liu
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
- Institute of Marine Science and Technology, Shandong University, Qingdao266237, China
| | - Michael Gonsior
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, Maryland20688, United States
| | - Rui Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Lianbao Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Hugh L MacIntyre
- Department of Oceanography, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Xiaowei Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Chen Hu
- College of the Environment and Ecology, Xiamen University, Xiamen361102, China
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - John Batt
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
- Department of Oceanography, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Qiang Shi
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
- Department of Oceanography, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Dapeng Xu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Yao Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
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3
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Wang C, Zhang H, Liu P, Wang Y, Sun Y, Song Z, Hu X. Divergent Patterns of Bacterial Community Structure and Function in Response to Estuarine Output in the Middle of the Bohai Sea. Front Microbiol 2021; 12:630741. [PMID: 33763048 PMCID: PMC7982528 DOI: 10.3389/fmicb.2021.630741] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/08/2021] [Indexed: 12/11/2022] Open
Abstract
Understanding environment-community relationships under shifting environmental conditions helps uncover mechanisms by which environmental microbial communities manage to improve ecosystem functioning. This study investigated the microbial community and structure near the Yellow Sea River estuary in 12 stations across the middle of the Bohai Sea for over two seasons to elucidate the influence of estuarine output on them. We found that the dominant phyla in all stations were Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, and Planctomycetes. Alpha-diversity increased near the estuary and bacterial community structure differed with variation of spatiotemporal gradients. Among all the environmental factors surveyed, temperature, salinity, phosphate, silicon, nitrate, and total virioplankton abundance played crucial roles in controlling the bacterial community composition. Some inferred that community functions such as carbohydrate, lipid, amino acid metabolism, xenobiotics biodegradation, membrane transport, and environmental adaptation were much higher in winter; energy and nucleotide metabolism were lower in winter. Our results suggested that estuarine output had a great influence on the Bohai Sea environment and changes in the water environmental conditions caused by estuarine output developed distinctive microbial communities in the middle of the Bohai Sea. The distinctive microbial communities in winter demonstrated that the shifting water environment may stimulate changes in the diversity and then strengthen the predicted functions.
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Affiliation(s)
- Caixia Wang
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Haikun Zhang
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Pengyuan Liu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yibo Wang
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yanyu Sun
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zenglei Song
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoke Hu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
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Individual Physiological Adaptations Enable Selected Bacterial Taxa To Prevail during Long-Term Incubations. Appl Environ Microbiol 2019; 85:AEM.00825-19. [PMID: 31152013 DOI: 10.1128/aem.00825-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 05/24/2019] [Indexed: 01/22/2023] Open
Abstract
Enclosure experiments are frequently used to investigate the impact of changing environmental conditions on microbial assemblages. Yet, how the incubation itself challenges complex bacterial communities is thus far unknown. In this study, metaproteomic profiling, 16S rRNA gene analyses, and cell counts were combined to evaluate bacterial communities derived from marine, mesohaline, and oligohaline conditions after long-term batch incubations. Early in the experiment, the three bacterial communities were highly diverse and differed significantly in their compositions. Manipulation of the enclosures with terrigenous dissolved organic carbon resulted in notable differences compared to the control enclosures at this early phase of the experiment. However, after 55 days, bacterial communities in the manipulated and the control enclosures under marine and mesohaline conditions were all dominated by gammaproteobacterium Spongiibacter In the oligohaline enclosures, actinobacterial cluster I of the hgc group (hgc-I) remained abundant in the late phase of the incubation. Metaproteome analyses suggested that the ability to use outer membrane-based internal energy stores, in addition to the previously described grazing resistance, may enable the gammaproteobacterium Spongiibacter to prevail in long-time incubations. Under oligohaline conditions, the utilization of external recalcitrant carbon appeared to be more important (hgc-I). Enclosure experiments with complex natural microbial communities are important tools to investigate the effects of manipulations. However, species-specific properties, such as individual carbon storage strategies, can cause manipulation-independent effects and need to be considered when interpreting results from enclosures.IMPORTANCE In microbial ecology, enclosure studies are often used to investigate the effect of single environmental factors on complex bacterial communities. However, in addition to the manipulation, unintended effects ("bottle effect") may occur due to the enclosure itself. In this study, we analyzed the bacterial communities that originated from three different salinities of the Baltic Sea, comparing their compositions and physiological activities both at the early stage and after 55 days of incubation. Our results suggested that internal carbon storage strategies impact the success of certain bacterial species, independent of the experimental manipulation. Thus, while enclosure experiments remain valid tools in environmental research, microbial community composition shifts must be critically followed. This investigation of the metaproteome during long-term batch enclosures expanded our current understanding of the so-called "bottle effect," which is well known to occur during enclosure experiments.
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5
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Wang X, Jiang L, Gai Z, Tao F, Tang H, Xu P. The plasticity of indigenous microbial community in a full-scale heavy oil-produced water treatment plant. JOURNAL OF HAZARDOUS MATERIALS 2018; 358:155-164. [PMID: 29990802 DOI: 10.1016/j.jhazmat.2018.06.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/08/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Indigenous microbial communities are main and promising performers for bioremediation due to their excellent adaptability, degradation capability, and inherent plasticity. Treating heavy oil-produced water (HOPW) is a challenge owing to the high recalcitrance and heterogeneity of chemicals it contains. A full-scale HOPW treatment plant was built at a capacity of 10,000 m3/d with the indigenous microbial community. After the treatment, the outlet water reached the design standard. The microbial community structures in all treatment stages were analyzed by using Illumina MiSeq 16S rRNA gene sequencing. The composition of microbial community changed greatly with the changes in environmental conditions, especially with the only artificially regulated parameter of dissolved oxygen. In the anaerobic stage, the community converted the recalcitrant chemical oxygen demand to biological oxygen demand (BOD), and played a major role in enhancing the biodegradability of HOPW. During the aerobic stage, the community mainly mineralized BOD. These results suggest that the structures of indigenous microbial community differed in different treatment stages to accomplish the corresponding functions. Based on these findings, it is proposed that exploiting the plasticity of microbial communities for bioremediation is feasible, especially treating wastewater with varied components.
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Affiliation(s)
- Xiaoyu Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Limin Jiang
- Jinuson Bioengineering Co., Ltd., Daqing 163161, Heilongjiang, People's Republic of China
| | - Zhonghui Gai
- Jinuson Bioengineering Co., Ltd., Daqing 163161, Heilongjiang, People's Republic of China
| | - Fei Tao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Hongzhi Tang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
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6
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Zhu L, Zhou H, Xie X, Li X, Zhang D, Jia L, Wei Q, Zhao Y, Wei Z, Ma Y. Effects of floodgates operation on nitrogen transformation in a lake based on structural equation modeling analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 631-632:1311-1320. [PMID: 29727955 DOI: 10.1016/j.scitotenv.2018.03.134] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/26/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Floodgates operation is one of the primary means of flood control in lake development. However, knowledge on the linkages between floodgates operation and nitrogen transformation during the flood season is limited. In this study, water samples from six sampling sites along Lake Xingkai watershed were collected before and after floodgates operation. The causal relationships between environmental factors, bacterioplankton community composition and nitrogen fractions were determined during flood season. We found that concentrations of nitrogen fractions decreased significantly when the floodgates were opened, while the concentrations of total nitrogen (TN) and NO3- increased when the floodgates had been shut for a period. Further, we proposed a possible mechanism that the influence of floodgates operation on nitrogen transformation was largely mediated through changes in dissolved organic matter, dissolved oxygen and bacterioplankton community composition as revealed by structural equation modeling (SEM). We conclude that floodgates operation has a high risk for future eutrophication of downstream watershed, although it can reduce nitrogen content temporarily. Therefore, the environmental impacts of floodgates operation should be carefully evaluated before the floodwaters were discharged into downstream watershed.
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Affiliation(s)
- Longji Zhu
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Haixuan Zhou
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Xinyu Xie
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Xueke Li
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Duoying Zhang
- School of Civil Engineering, Heilongjiang University, Harbin 150080, China
| | - Liming Jia
- Environmental Monitoring Center of Heilongjiang Province, Harbin 150056, China
| | - Qingbin Wei
- Environmental Monitoring Center of Heilongjiang Province, Harbin 150056, China
| | - Yue Zhao
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Zimin Wei
- College of Life Science, Northeast Agricultural University, Harbin 150030, China.
| | - Yingying Ma
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
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Osterholz H, Kirchman DL, Niggemann J, Dittmar T. Diversity of bacterial communities and dissolved organic matter in a temperate estuary. FEMS Microbiol Ecol 2018; 94:5037919. [DOI: 10.1093/femsec/fiy119] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/10/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Helena Osterholz
- ICBM-MPI Bridging Group for Marine Geochemistry, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University, Oldenburg, Germany
| | - David L Kirchman
- School of Marine Science and Policy, University of Delaware, Lewes, DE 19958, USA
| | - Jutta Niggemann
- ICBM-MPI Bridging Group for Marine Geochemistry, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University, Oldenburg, Germany
| | - Thorsten Dittmar
- ICBM-MPI Bridging Group for Marine Geochemistry, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University, Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity, Carl von Ossietzky University, Oldenburg, Germany
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8
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Shen D, Jürgens K, Beier S. Experimental insights into the importance of ecologically dissimilar bacteria to community assembly along a salinity gradient. Environ Microbiol 2018; 20:1170-1184. [DOI: 10.1111/1462-2920.14059] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 12/18/2017] [Accepted: 01/27/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Dandan Shen
- Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Department of Biological Oceanography, Seestr. 15; D-18119 Rostock Germany
| | - Klaus Jürgens
- Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Department of Biological Oceanography, Seestr. 15; D-18119 Rostock Germany
| | - Sara Beier
- Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Department of Biological Oceanography, Seestr. 15; D-18119 Rostock Germany
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Klier J, Dellwig O, Leipe T, Jürgens K, Herlemann DPR. Benthic Bacterial Community Composition in the Oligohaline-Marine Transition of Surface Sediments in the Baltic Sea Based on rRNA Analysis. Front Microbiol 2018; 9:236. [PMID: 29520255 PMCID: PMC5827536 DOI: 10.3389/fmicb.2018.00236] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/31/2018] [Indexed: 12/16/2022] Open
Abstract
Salinity has a strong impact on bacterial community composition such that freshwater bacterial communities are very different from those in seawater. By contrast, little is known about the composition and diversity of the bacterial community in the sediments (bacteriobenthos) at the freshwater-seawater transition (mesohaline conditions). In this study, partial 16S-rRNA sequences were used to investigate the bacterial community at five stations, representing almost freshwater (oligohaline) to marine conditions, in the Baltic Sea. Samples were obtained from the silty, top-layer (0-2.5 cm) sediments with mostly oxygenated conditions. The long water residence time characteristic of the Baltic Sea, was predicted to enable the development of autochthonous bacteriobenthos at mesohaline conditions. Our results showed that, similar to the water column, salinity is a major factor in structuring the bacteriobenthos and that there is no loss of bacterial richness at intermediate salinities. The bacterial communities of marine, mesohaline, and oligohaline sediments differed in terms of the relative rRNA abundances of the major bacterial phyla/classes. At mesohaline conditions typical marine and oligohaline operational taxonomic units (OTUs) were abundant. Putative unique OTUs in mesohaline sediments were present only at low abundances, suggesting that the mesohaline environment consists mainly of marine and oligohaline bacteria with a broad salinity tolerance. Our study provides a first overview of the diversity patterns and composition of bacteria in the sediments along the Baltic Sea salinity gradient as well as new insights into the bacteriobenthos at mesohaline conditions.
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Affiliation(s)
- Julia Klier
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - Olaf Dellwig
- Department of Marine Geology, Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - Thomas Leipe
- Department of Marine Geology, Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - Klaus Jürgens
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - Daniel P. R. Herlemann
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Rostock, Germany
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