Regime transition Shapes the Composition, Assembly Processes, and Co-occurrence Pattern of Bacterioplankton Community in a Large Eutrophic Freshwater Lake

Abstract At certain nutrient concentrations, shallow freshwater lakes are generally characterized by two contrasting ecological regimes with disparate patterns of biodiversity and biogeochemical cycles: a macrophyte-dominated regime (MDR) and a phytoplankton-dominated regime (PDR).To reveal ecological mechanisms that affect bacterioplankton along the regime shift, Illumina MiSeq sequencing of the 16S rRNA gene combined with a novel network clustering tool (Manta) were used to identify patterns of bacterioplankton community composition across the regime shift in Taihu Lake, China. Marked divergence in the composition and ecological assembly processes of bacterioplankton community were observed under the regime shift. The alpha diversity of bacterioplankton community was observed to consistently and continuously decrease with the regime shift from MDR to PDR, while the beta diversity presents the opposite. Moreover, as the regime shifted from MDR to PDR, the contribution of deterministic processes first decreased and then increased again closer to the PDR, most likely as a consequence of differences in nutrient concentration. The topological properties of bacterioplankton co-occurrence networks along the regime shift differed, and the co-occurrences among species changed in structure and were significantly shaped by the environmental variables along the regime transition from MDR to PDR. The divergent environmental state of the regimes with diverse nutritional status may be the most important factor that contributes to the dissimilarity of bacterioplankton community composition along the regime shift and could be represented by phosphorus concentrations as well as several indicator species.

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Macrophyte Species Drive the Variation of Bacterioplankton Community Composition in a Shallow Freshwater Lake

Applied and Environmental Microbiology ◽

10.1128/aem.05117-11 ◽

2011 ◽

Vol 78 (1) ◽

pp. 177-184 ◽

Cited By ~ 44

Author(s):

Jin Zeng ◽

Yuanqi Bian ◽

Peng Xing ◽

Qinglong L. Wu

Keyword(s):

Community Composition ◽

Denaturing Gradient Gel Electrophoresis ◽

Single Species ◽

Freshwater Lake ◽

Clone Libraries ◽

Bacterioplankton Community ◽

Macrophyte Species ◽

Gradient Gel Electrophoresis ◽

Microcosm Studies ◽

Species Specific

ABSTRACTMacrophytes play an important role in structuring aquatic ecosystems. In this study, we explored whether macrophyte species are involved in determining the bacterioplankton community composition (BCC) in shallow freshwater lakes. The BCC in field areas dominated by different macrophyte species in Taihu Lake, a large, shallow freshwater lake, was investigated over a 1-year period. Subsequently, microcosm experiments were conducted to determine if single species of different types of macrophytes in an isolated environment would alter the BCC. Denaturing gradient gel electrophoresis (DGGE), followed by cloning and sequence analysis of selected samples, was employed to analyze the BCC. The DGGE results of the field investigations indicated that the BCC changed significantly from season to season and that the presence of different macrophyte species resulted in lower BCC similarities in the summer and fall. LIBSHUFF analysis of selected clone libraries from the summer demonstrated different BCCs in the water column surrounding different macrophytes. Relative to the field observations, the microcosm studies indicated that the BCC differed more pronouncedly when associated with different species of macrophytes, which was also supported by LIBSHUFF analysis of the selected clone libraries. Overall, this study suggested that macrophyte species might be an important factor in determining the composition of bacterial communities in this shallow freshwater lake and that the species-specific influence of macrophytes on BCC is variable with the season and distance.

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Seasonal dynamics of the bacterioplankton community in a large, shallow, highly dynamic freshwater lake

Canadian Journal of Microbiology ◽

10.1139/cjm-2018-0126 ◽

2018 ◽

Vol 64 (11) ◽

pp. 786-797 ◽

Cited By ~ 3

Author(s):

Zhaoyu Kong ◽

Wenbo Kou ◽

Yantian Ma ◽

Haotian Yu ◽

Gang Ge ◽

...

Keyword(s):

Water Level ◽

Relative Abundance ◽

Poyang Lake ◽

Nutrient Status ◽

Diversity Indices ◽

Freshwater Lake ◽

Rrna Gene ◽

Bacterioplankton Community ◽

Α Diversity ◽

Composition Structure

The spatiotemporal shifts of the bacterioplankton community can mirror their transition of functional traits in an aquatic ecosystem. However, the spatiotemporal variation of the bacterioplankton community composition structure (BCCS) within a large, shallow, highly dynamic freshwater lake is still poorly understood. Here, we examined the seasonal and spatial variability of the BCCs within Poyang Lake by sequencing the 16S rRNA gene amplicon to explore how hydrological changes affect the BCCs. Principal coordinate analysis showed that the BCCs varied significantly among four sampling seasons, but not spatially. The seasonal changes of the BCCs were mainly attributed to the differences between autumn and spring–winter. Higher α diversity indices were observed in autumn. Redundancy analysis indicated that the BCCs co-variated with water level, pH, temperature, total phosphorus, ammoniacal nitrogen, electrical conductivity, total nitrogen, and turbidity. Among them, water level was the key determinant separating autumn BCCs from the BCCs in other seasons. A significantly lower relative abundance of Burkholderiales (betI and betVII) and a higher relative abundance of Actinomycetales (acI, acTH1, and acTH2) were found in autumn than in other seasons. Overall, our results suggest that water level changes associated with pH, temperature, and nutrient status shaped the seasonal patterns of the BCCs within Poyang Lake.

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Significant changes in the bacterioplankton community structure of a maritime Antarctic freshwater lake following nutrient enrichment

Microbiology ◽

10.1099/mic.0.27258-0 ◽

2005 ◽

Vol 151 (10) ◽

pp. 3237-3248 ◽

Cited By ~ 33

Author(s):

David A. Pearce ◽

Christopher J. van der Gast ◽

Kelly Woodward ◽

Kevin K. Newsham

Keyword(s):

Population Density ◽

Environmental Change ◽

Nutrient Enrichment ◽

Denaturing Gradient Gel Electrophoresis ◽

Acid Methyl Ester ◽

Freshwater Lake ◽

Rrna Gene ◽

Maritime Antarctic ◽

Lake Chemistry ◽

Bacterioplankton Community

Nutrient enrichment is known to increase bacterioplankton population density in a variety of Antarctic freshwater lakes. However, relatively little is known about the associated changes in species composition. In this study, the bacterioplankton community composition of one such lake was studied following natural nutrient enrichment to investigate the resistance of the system to environmental change. Heywood Lake is an enriched freshwater maritime Antarctic lake, with nitrogen and phosphorus concentrations significantly higher than its more oligotrophic neighbours (by at least an order of magnitude). This major change in lake chemistry has occurred following large increases in the fur seal population over the last 30 years. Using analysis of 16S rRNA gene fragments, fatty acid methyl ester analysis, denaturing gradient gel electrophoresis and fluorescence in situ hybridization, significant changes are reported in lake microbiology which have resulted in a distinct bacterioplankton community. In comparison to its more oligotrophic neighbours, nutrient-enriched Heywood Lake has a high bacterioplankton population density, reduced species richness and an increasing evenness among key groups. Only 42·3 % of the clones found with ≥97 % similarity to a named genus were also present in adjacent oligotrophic lakes, including three of the dominant groups. Critically, there was an apparent shift in dominance with trophic status (from the β-Proteobacteria to the Actinobacteria). Other key observations included the absence of a dominant group of Cyanobacteria and the presence of marine bacteria. The significant impact of natural nutrient enrichment on the microbiology of Heywood Lake, therefore, suggests that low-temperature oligotrophic freshwater lake systems might have low resistance to environmental change.

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Filling a Freshwater Lake—Sediment Remediation Considering Net Environmental Benefit for Multiple Stakeholder Goals

Ports 2019 ◽

10.1061/9780784482629.004 ◽

2019 ◽

Author(s):

Jessi Massingale ◽

Megan King ◽

Don Robbins

Keyword(s):

Lake Sediment ◽

Freshwater Lake ◽

Environmental Benefit ◽

Sediment Remediation ◽

Multiple Stakeholder

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Contribution of large bacteria to bacterial biomass in a deep freshwater lake (Lake Biwa, Japan)

Aquatic Microbial Ecology ◽

10.3354/ame01949 ◽

2020 ◽

Vol 85 ◽

pp. 131-139

Author(s):

S Shen ◽

Y Shimizu

Keyword(s):

Cell Volume ◽

Bacterial Cell ◽

Lake Biwa ◽

Bacterial Biomass ◽

Spatial Variations ◽

Freshwater Lake ◽

Heterotrophic Nanoflagellates ◽

Bacterial Productivity ◽

Transmission Electron ◽

Seasonal And Spatial Variations

Despite the importance of bacterial cell volume in microbial ecology in aquatic environments, literature regarding the effects of seasonal and spatial variations on bacterial cell volume remains scarce. We used transmission electron microscopy to examine seasonal and spatial variations in bacterial cell size for 18 mo in 2 layers (epilimnion 0.5 m and hypolimnion 60 m) of Lake Biwa, Japan, a large and deep freshwater lake. During the stratified period, we found that the bacterial cell volume in the hypolimnion ranged from 0.017 to 0.12 µm3 (median), whereas that in the epilimnion was less variable (0.016 to 0.033 µm3, median) and much lower than that in the hypolimnion. Additionally, in the hypolimnion, cell volume during the stratified period was greater than that during the mixing period (up to 5.7-fold). These differences in cell volume resulted in comparable bacterial biomass in the hypolimnion and epilimnion, despite the fact that there was lower bacterial abundance in the hypolimnion than in the epilimnion. We also found that the biomass of larger bacteria, which are not likely to be grazed by heterotrophic nanoflagellates, increased in the hypolimnion during the stratified period. Our data suggest that estimation of carbon flux (e.g. bacterial productivity) needs to be interpreted cautiously when cell volume is used as a constant parametric value. In deep freshwater lakes, a difference in cell volume with seasonal and spatial variation may largely affect estimations.

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