scholarly journals Bacterial Communities Along Environmental Gradients in Tropical Soda Lakes

Author(s):  
Thierry A. Pellegrinetti ◽  
Simone R. Cotta ◽  
Hugo Sarmento ◽  
Juliana S. Costa ◽  
Endrews Delbaje ◽  
...  

Abstract Soda lakes environment is known to be variable and can have distinct differences according to geographical location. In this study, we investigated the effect of different environmental conditions of six adjacent soda lakes on bacterial communities and their functioning using a metagenomic approach combined with flow cytometry and chemical analyses. Ordination analysis using flow cytometry and water chemistry data from two sampling periods (wet and dry) clustered soda lakes in three different profiles: eutrophic turbid (ET), oligotrophic turbid (OT), and clear vegetated oligotrophic (CVO). Analysis of bacterial community composition and functioning corroborated this ordination; the exception was one ET lake, that was similar to one OT lake during the wet season, indicating drastic shifts between seasons. Microbial abundance and diversity increased during the dry period, along with a considerable number of limnological variables, all indicative of a strong effect of the precipitation-evaporation balance in these systems. Cyanobacteria were linked to high electric conductivity, pH, and nutrient availability, whereas Actinobacteria, Alphaproteobacteria, and Betaproteobacteria were correlated with landscape morphology variability (surface water, surface perimeter, and lake volume) and less stressed lake conditions. Stress response metabolism was overrepresented in ET and OT lakes and underrepresented in CVO lakes. Altogether, this study illustrated the sensitivity of tropical soda lakes to climate change, as slight changes in hydrological regimes might produce drastic shifts in community diversity.

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5508 ◽  
Author(s):  
Yan Li ◽  
Yan Kong ◽  
Dexiong Teng ◽  
Xueni Zhang ◽  
Xuemin He ◽  
...  

BackgroundRecently, researches have begun to investigate the microbial communities associated with halophytes. Both rhizobacterial community composition and the environmental drivers of community assembly have been addressed. However, few studies have explored the structure of rhizobacterial communities associated with halophytic plants that are co-occurring in arid, salinized areas.MethodsFive halophytes were selected for study: these co-occurred in saline soils in the Ebinur Lake Nature Reserve, located at the western margin of the Gurbantunggut Desert of Northwestern China. Halophyte-associated bacterial communities were sampled, and the bacterial 16S rDNA V3–V4 region amplified and sequenced using the Illumina Miseq platform. The bacterial community diversity and structure were compared between the rhizosphere and bulk soils, as well as among the rhizosphere samples. The effects of plant species identity and soil properties on the bacterial communities were also analyzed.ResultsSignificant differences were observed between the rhizosphere and bulk soil bacterial communities. Diversity was higher in the rhizosphere than in the bulk soils. Abundant taxonomic groups (from phylum to genus) in the rhizosphere were much more diverse than in bulk soils. Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Planctomycetes were the most abundant phyla in the rhizosphere, while Proteobacteria and Firmicutes were common in bulk soils. Overall, the bacterial community composition were not significantly differentiated between the bulk soils of the five plants, but community diversity and structure differed significantly in the rhizosphere. The diversity ofHalostachys caspica,Halocnemum strobilaceumandKalidium foliatumassociated bacterial communities was lower than that ofLimonium gmeliniiandLycium ruthenicumcommunities. Furthermore, the composition of the bacterial communities ofHalostachys caspicaandHalocnemum strobilaceumwas very different from those ofLimonium gmeliniiandLycium ruthenicum. The diversity and community structure were influenced by soil EC, pH and nutrient content (TOC, SOM, TON and AP); of these, the effects of EC on bacterial community composition were less important than those of soil nutrients.DiscussionHalophytic plant species played an important role in shaping associated rhizosphere bacterial communities. When salinity levels were constant, soil nutrients emerged as key factors structuring bacterial communities, while EC played only a minor role. Pairwise differences among the rhizobacterial communities associated with different plant species were not significant, despite some evidence of differentiation. Further studies involving more halophyte species, and individuals per species, are necessary to elucidate plant species identity effects on the rhizosphere for co-occurring halophytes.


2020 ◽  
Vol 12 (5) ◽  
pp. 1864
Author(s):  
Jiling Cao ◽  
Yuxiong Zheng ◽  
Yusheng Yang

Despite increasing investigations having studied the changing patterns of soil microbial communities along forest plantation development age sequences, the underlying phylogenetic assemblages are seldom studied for microbial community. Here, the soil bacterial taxonomic and phylogenetic diversity as well as the phylogenetic structure were examined to elucidate the community diversity and assembly in three typical ages (young, middle and mature) of Cunninghamia lanceolata plantations, a dominant economic tree species in southern China. Results indicated that the soil bacterial phylogenetic not taxonomic diversity increased with the increasing in stand age. The bacterial community composition differed significantly among the young, middle and mature plantations. Phylogenetic signals showed that bacterial communities were phylogenetically clustered and structured by environmental filtering in all studied plantations. In mature plantation, the effect of environmental filtering becomes stronger and bacteria taxa tend to intraspecific interact more complexly as characterized by co-occurrence network analysis. This suggests that ecological niche-based environmental filtering could be a dominant assembly process that structured the soil bacterial community along age sequences of Cunninghamia lanceolata plantations.


mSphere ◽  
2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Alexandra M. Linz ◽  
Benjamin C. Crary ◽  
Ashley Shade ◽  
Sarah Owens ◽  
Jack A. Gilbert ◽  
...  

ABSTRACT Lakes are excellent systems for investigating bacterial community dynamics because they have clear boundaries and strong environmental gradients. The results of our research demonstrate that bacterial community composition varies by year, a finding which likely applies to other ecosystems and has implications for study design and interpretation. Understanding the drivers and controls of bacterial communities on long time scales would improve both our knowledge of fundamental properties of bacterial communities and our ability to predict community states. In this specific ecosystem, bog lakes play a disproportionately large role in global carbon cycling, and the information presented here may ultimately help refine carbon budgets for these lakes. Finally, all data and code in this study are publicly available. We hope that this will serve as a resource for anyone seeking to answer their own microbial ecology questions using a multiyear time series. Bacteria play a key role in freshwater biogeochemical cycling, but long-term trends in freshwater bacterial community composition and dynamics are not yet well characterized. We used a multiyear time series of 16S rRNA gene amplicon sequencing data from eight bog lakes to census the freshwater bacterial community and observe annual and seasonal trends in abundance. The sites that we studied encompassed a range of water column mixing frequencies, which we hypothesized would be associated with trends in alpha and beta diversity. Each lake and layer contained a distinct bacterial community, with distinct levels of richness and indicator taxa that likely reflected the environmental conditions of each lake type sampled, including Actinobacteria in polymictic lakes (i.e., lakes with multiple mixing events per year), Methylophilales in dimictic lakes (lakes with two mixing events per year, usually in spring and fall), and “Candidatus Omnitrophica” in meromictic lakes (lakes with no recorded mixing events). The community present during each year at each site was also surprisingly unique. Despite unexpected interannual variability in community composition, we detected a core community of taxa found in all lakes and layers, including Actinobacteria tribe acI-B2 and Betaprotobacteria lineage PnecC. Although trends in abundance did not repeat annually, each freshwater lineage within the communities had a consistent lifestyle, defined by persistence, abundance, and variability. The results of our analysis emphasize the importance of long-term multisite observations, as analyzing only a single year of data or one lake would not have allowed us to describe the dynamics and composition of these freshwater bacterial communities to the extent presented here. IMPORTANCE Lakes are excellent systems for investigating bacterial community dynamics because they have clear boundaries and strong environmental gradients. The results of our research demonstrate that bacterial community composition varies by year, a finding which likely applies to other ecosystems and has implications for study design and interpretation. Understanding the drivers and controls of bacterial communities on long time scales would improve both our knowledge of fundamental properties of bacterial communities and our ability to predict community states. In this specific ecosystem, bog lakes play a disproportionately large role in global carbon cycling, and the information presented here may ultimately help refine carbon budgets for these lakes. Finally, all data and code in this study are publicly available. We hope that this will serve as a resource for anyone seeking to answer their own microbial ecology questions using a multiyear time series.


2016 ◽  
Vol 62 (6) ◽  
pp. 455-463 ◽  
Author(s):  
Lei Zhang ◽  
Guang Gao ◽  
Xiangming Tang ◽  
Keqiang Shao ◽  
Yi Gong

The bacteria inhabiting brackish lake environments are poorly known, and there are few studies on the microbial diversity of these environments. Lake Bosten, a large brackish inland lake, is the largest lake in Xinjiang Province in northwestern China. Because sediments record past limnic changes, the analysis of sedimentary bacteria in Lake Bosten may help elucidate bacterial responses to environmental change. We employed 454 pyrosequencing to investigate the diversity and bacterial community composition in Lake Bosten. A total of 48 230 high-quality sequence reads with 16 314 operational taxonomic units were successfully obtained from the 4 selected samples, and they were numerically dominated by members of the Deltaproteobacteria (17.1%), Chloroflexi (16.1%), Betaproteobacteria (12.6%), Bacteroidetes (6.6%), and Firmicutes (5.7%) groups, accounting for more than 58.1% of the bacterial sequences. The sediment bacterial communities and diversity were consistently different along the 2 geographic environmental gradients: (i) freshwater–brackish water gradient and (ii) oligotrophic–mesotrophic habitat gradient. Deltaproteobacteria, Chloroflexi, and Betaproteobacteria were amplified throughout all of the sampling sites. More Bacteroidetes and Firmicutes were found near the Kaidu River estuary (site 14). Our investigation showed that Proteobacteria did not display any systematic change along the salinity gradient, and numerous 16S rRNA sequences could not be identified at the genus level. Our data will provide a better understanding of the diversity and distribution of bacteria in arid region brackish lakes.


2020 ◽  
Vol 96 (5) ◽  
Author(s):  
William L King ◽  
Nachshon Siboni ◽  
Tim Kahlke ◽  
Michael Dove ◽  
Wayne O'Connor ◽  
...  

ABSTRACT Different organs of a host represent distinct microenvironments resulting in the establishment of multiple discrete bacterial communities within a host. These discrete bacterial communities can also vary according to geographical location. For the Pacific oyster, Crassostrea gigas, the factors governing bacterial diversity and abundance of different oyster microenvironments are poorly understood. In this study, the factors shaping bacterial abundance, diversity and composition associated with the C. gigas mantle, gill, adductor muscle and digestive gland were characterised using 16S (V3-V4) rRNA amplicon sequencing across six discrete estuaries. Both location and tissue-type, with tissue-type being the stronger determinant, were factors driving bacterial community composition. Bacterial communities from wave-dominated estuaries had similar compositions and higher bacterial abundance despite being geographically distant from one another, possibly indicating that functional estuarine morphology characteristics are a factor shaping the oyster bacterial community. Despite the bacterial community heterogeneity, examinations of the core bacterial community identified Spirochaetaceae bacteria as conserved across all sites and samples. Whereas members of the Vulcaniibacterium, Spirochaetaceae and Margulisbacteria, and Polynucleobacter were regionally conserved members of the digestive gland, gill and mantle bacterial communities, respectively. This indicates that baseline bacterial community profiles for specific locations are necessary when investigating bacterial communities in oyster health.


2019 ◽  
Vol 48 (1) ◽  
pp. 43-55
Author(s):  
Qiao Liu ◽  
Mengmeng Liu ◽  
Qi Zhang ◽  
Yanlin Bao ◽  
Na Yang ◽  
...  

Abstract In this study, we conducted a comparative analysis of the abundance and diversity of bacteria on the surface of the submerged macrophyte Myriophyllum spicatum, as well as in the surrounding water column and sediment in the low-salinity area of Hangzhou Bay, China. Bacterial clones from three clone libraries were classified into 2089 operational taxonomic units (OTUs), most of which affiliated with bacterial divisions commonly found in marine ecosystems. Alphaproteobacteria, Cyanobacteria and Gammaproteobacteria were the most abundant groups of bacteria on the surface of plants, in the water column and sediment, respectively. Epiphytic bacterial communities were more closely related to those in the sediment than bacterioplankton, and some species of epiphytic bacteria were found only on the surface of M. spicatum. The relative abundance of epiphytic bacterial genera associated with breakdown of organic compounds and with cellulose digestion was higher in October than that in July. These results suggested that bacterial communities on the surface of M. spicatum may originate from sediment bacterial communities and their specific structure was gradually formed on the surface of M. spicatum after being cultivated in low-salinity seawater.


2020 ◽  
Author(s):  
Zhang Tao ◽  
Dang Han Li ◽  
Wang Zhong Ke ◽  
Lv Xin Hua ◽  
Zhuang Li

Abstract Background Ferula sinkiangensis is a desert short-lived medicinal plant, and its number is rapidly decreasing. Rhizosphere microbial community plays an important role in regulating global biogeochemical cycle, plant growth and adaptability. However, the Ferula sinkiangensis bacterial community and the processes that drive its assembly remain unclear. Results In this study, based on Illumina HiSeq high-throughput sequencing, we explored the diversity, structure and composition of Ferula sinkiangensis rhizosphere bacterial communities at different slope positions (upper, middle and bottom) and soil depths (0-10 cm, 10-25 cm, 25-40 cm) and their correlation with soil physicochemical properties. Actinobacteria (22.7%), Proteobacteria (18.6%), Acidobacteria (14.0%), Gemmatimonadetes (10.1%), Cyanobacteria (7.9%), Bacteroidetes (6.9%), Planctomycetes (3.9%), Verrucomicrobia (3.5%), Firmicutes (3.4%) and Chloroflexi (3.2%) were the dominant bacterial phyla in Ferula sinkiangensis rhizosphere soil. Variance analysis showed that the diversity and abundance of rhizosphere bacterial community in Ferula sinkiangensis were significantly different at various slope positions and soil depths. Specifically, the diversity of bacterial community was significantly higher at the top than the bottom of the slope, and the diversity and richness of bacterial community were significantly greater in the 0-10cm than the 25-40cm soil layer. Linear discriminant effect size (LEfSe) analysis showed the specific phyla and genera of bacteria affected by slope position and soil depth. For example, Planctomycetes, Sphingomonas , Rubrobacter and Adhaeribacter by slope position and significant impact on soil depth. In addition, distance-based redundancy analysis (db-RDA) and variance analysis showed that soil physicochemical factors jointly explained 29.81% of variation in Ferula sinkiangensis rhizosphere bacterial community structure. There was a significant positive correlation between available phosphorus(AP)and the diversity of Ferula sinkiangensis rhizosphere bacterial community ( p < 0.01), whereas pH largely explained the variation of Ferula sinkiangensis rhizosphere bacterial community structure (5.58%, p < 0.01), followed by altitude (5.53%), total salt (TS, 5.21%) and total phosphorus (TP, 4.90%). Conclusion Our results revealed the heterogeneity and variation trends of Ferula sinkiangensis rhizosphere bacterial community diversity and abundance on a fine spatial scale (slope position and depth) and shed new light on the mechanisms of coevolution and interaction between Ferula sinkiangensis and their rhizosphere bacterial communities across environmental gradients.


Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 542
Author(s):  
Yeon-Ji Chae ◽  
Hye-Ji Oh ◽  
Kwang-Hyeon Chang ◽  
Ihn-Sil Kwak ◽  
Hyunbin Jo

The gut bacterial communities of copepods can affect metabolic processes, and consequently, their activity can be related to the release of organic substances to the environment. Hence, they are important for organic matter cycling in marine coast food webs. However, information regarding the variation in gut bacterial communities based on copepod species and environmental variations is limited. We analysed the differences in gut bacterial communities from dominant copepod species, i.e., Acartia hudsonica, Sinocalanus tenellus, and Pseudodiaptomus inopinus, in a brackish reservoir. The core bacteria among the copepod species and locations consisted of the following main operational taxonomic units (OTUs): Novosphingobium capsulatum and the family Rhodobacteraceae belonging to Alphaproteobacteria, which is abundant in seawater and freshwater aquatic ecosystems as a zooplankton-associated bacterial community. The bacterial community composition of each copepod (except the core species) showed high variability. The bacterial community diversity differed depending on the copepod species and the sites’ environmental conditions, especially salinity, e.g., compositional variations in the bacterial community of P. inopinus were high at sites with low salinity. Therefore, the gut bacterial community of each copepod species responds differently to the environment.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jemma L Geoghegan ◽  
Francesca Di Giallonardo ◽  
Michelle Wille ◽  
Ayda Susana Ortiz-Baez ◽  
Vincenzo A Costa ◽  
...  

Abstract Revealing the determinants of virome composition is central to placing disease emergence in a broader evolutionary context. Fish are the most species-rich group of vertebrates and so provide an ideal model system to study the factors that shape virome compositions and their evolution. We characterized the viromes of nineteen wild-caught species of marine fish using total RNA sequencing (meta-transcriptomics) combined with analyses of sequence and protein structural homology to identify divergent viruses that often evade characterization. From this, we identified twenty-five new vertebrate-associated viruses and a further twenty-two viruses likely associated with fish diet or their microbiomes. The vertebrate-associated viruses identified here included the first fish virus in the Matonaviridae (single-strand, negative-sense RNA virus). Other viruses fell within the Astroviridae, Picornaviridae, Arenaviridae, Reoviridae, Hepadnaviridae, Paramyxoviridae, Rhabdoviridae, Hantaviridae, Filoviridae, and Flaviviridae, and were sometimes phylogenetically distinct from known fish viruses. We also show how key metrics of virome composition—viral richness, abundance, and diversity—can be analysed along with host ecological and biological factors as a means to understand virus ecology. Accordingly, these data suggest that that the vertebrate-associated viromes of the fish sampled here are predominantly shaped by the phylogenetic history (i.e. taxonomic order) of their hosts, along with several biological factors including water temperature, habitat depth, community diversity and swimming behaviour. No such correlations were found for viruses associated with porifera, molluscs, arthropods, fungi, and algae, that are unlikely to replicate in fish hosts. Overall, these data indicate that fish harbour particularly large and complex viromes and the vast majority of fish viromes are undescribed.


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