scholarly journals Microbiome divergence across four major Indian riverine water ecosystems impacted by anthropogenic contamination: A comparative metagenomic analysis

Author(s):  
Raj Kumar Regar ◽  
Mohan Kamthan ◽  
Vivek Kumar gaur ◽  
Satyendra Pratap Singh ◽  
Seema Mishra ◽  
...  

Abstract Background Indian rivers are a major source of livelihood as river water is used for drinking, agriculture, and religious purposes to a large population. In this study, we report comparative microbial structures and functional potential of four major rivers of India, namely Ganga, Narmada, Cauvery, and Gomti. Comparative microbiome study of these geographically distinct rivers was performed using the samples collected from the source to the downstream sites of each river. We employed metagenomic approach to comprehensively determine the taxonomic and functional potential of river microbiome. Results In this study, we report the pollution influences on microbial composition and functional potential of four distantly located rivers. Results revealed significant microbial diversity in contaminated locations as compared to the upstream samples. A total number of 37 bacterial phyla were detected out of which Proteobacteria, Actinobacteria, Bacteroidetes, Planctomycetes, and Verrucomicrobia were abundant. Microbial diversity in respect to anthropogenic activities revealed the prevalence of Acidobacteria, Actinobacteria, Verrucomicrobia, Firmicutes, and Nitrospirae phyla, whereas a decline in Proteobacteria and Bacteroides. Virulent and temperate bacteriophages were found high in Ganga when compared to others. Interestingly, the abundance of bacteriophage decreased with increasing pollution load in the river Ganga, unlike in other rivers. The carbon utilization studies indicated a correlation with functional genes occurred in metal contaminated sites. Ganga water has relatively higher trace elements at pristine-upstream than in the Narmada and Cauvery, indicating its origin from Himalayan rocky mountains and also both Ganga and Cauvery rivers found to harbour a large number of metal resistance genes. Conclusion Our findings indicate a correlation between pollution and the microbiome composition. The insights obtained suggest the role of high abundance of microbial communities with implications for human health and demonstrate the functional capabilities contributed by the microbial communities. Among the four rivers studied, the distinctiveness of Ganga in comparison to others, particularly upstream of Ganga revealed a highly dynamic microbial structure. Bhagirathi and Alaknanda confluence to form Ganga, the microbiome revealed that Alaknanda has the foremost contribution to Ganga with respect to microbial community, bacteriophages, and the type of trace elements and heavy metals detected.

2020 ◽  
Vol 9 (1) ◽  
pp. 231-250
Author(s):  
Birendra Prasad Sharma ◽  
Subash Adhikari ◽  
Ganesh Paudel ◽  
Namita Paudel Adhikari

Microorganisms, as successive members of the food web, play a major role in biological processes. They are found in environments ranging from extremely hot to harsh cold temperatures. Thus, the study of bacterial communities in various ecosystems is of great concern around the world. The glacier is one of the parts of the cryosphere, which is the key component and sensitive indicator of climatic and environmental changes. A glacial ecosystem is a habitat for various microorganisms, i.e., autotrophic and heterotrophic. Different physicochemical parameters like temperature, pH, electrical conductivity, the input of nutrient concentration, precipitation, ions concentrations, etc. influence the microbial diversity in the glacial ecosystem for their metabolic processes. Successive studies of bacterial communities in the Himalayan glacial ecosystem are reliable proxies to know the relationships between microbial biodiversity and climate change since the Himalayan glaciers are free from anthropogenic activities. After the study of the relevant literature, it is clear that the researches. have been carried out in the Polar Regions, and the Tibetan plateau mainly focused on the glacial ecosystem. This review concluded that Proteobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, Verrucomicrobia, and Actinobacteria were the most dominant bacterial phyla via 16S rRNA clone libraries and Illumina MiSeq. Alter in landscapes, nutrient cycles, exposure of light, shifting on the concentration of different elements, glacier retreats were the major components for survival strength of dominant bacterial phyla. However, limited studies on the glacial ecosystem of the Himalayas have been published. Thus, the study of bacterial abundance, diversity, and community in the Himalayas will help plug this research gap.


2006 ◽  
Vol 72 (11) ◽  
pp. 6902-6906 ◽  
Author(s):  
Eitan Ben-Dov ◽  
Orr H. Shapiro ◽  
Nachshon Siboni ◽  
Ariel Kushmaro

ABSTRACT To overcome the shortcomings of universal 16S rRNA gene primers 8F and 907R when studying the diversity of complex microbial communities, the 3′ termini of both primers were replaced with inosine. A comparison of the clone libraries derived using both primer sets showed seven bacterial phyla amplified by the altered primer set (8F-I/907R-I) whereas the original set amplified sequences belonging almost exclusively to Proteobacteria (95.8%). Sequences belonging to Firmicutes (42.6%) and Thermotogae (9.3%) were more abundant in a library obtained by using 8F-I/907R-I at a PCR annealing temperature of 54°C, while Proteobacteria sequences were more frequent (62.7%) in a library obtained at 50°C, somewhat resembling the result obtained using the original primer set. The increased diversity revealed by using primers 8F-I/907R-I confirms the usefulness of primers with inosine at the 3′ termini in studying the microbial diversity of environmental samples.


2020 ◽  
Vol 21 (6) ◽  
pp. 1001-1010 ◽  
Author(s):  
Kathrin Busch ◽  
Lindsay Beazley ◽  
Ellen Kenchington ◽  
Frederick Whoriskey ◽  
Beate M. Slaby ◽  
...  

Abstract Establishment of adequate conservation areas represents a challenging but crucial task in the conservation of genetic diversity and biological variability. Anthropogenic pressures on marine ecosystems and organisms are steadily increasing. Whether and to what extent these pressures influence marine genetic biodiversity is only starting to be revealed. Using 16S rRNA gene amplicon sequencing, we analysed the microbial community structure of 33 individuals of the habitat-forming glass sponge Vazella pourtalesii, as well as reference seawater, sediment, and biofilm samples. We assessed how two anthropogenic impacts, i.e. habitat destruction by trawling and artificial substrate provision (moorings made of composite plastic), correspond with in situ V. pourtalesii microbiome variability. In addition, we evaluated the role of two bottom fishery closures in preserving sponge-associated microbial diversity on the Scotian Shelf, Canada. Our results illustrate that V. pourtalesii sponges collected from protected sites within fishery closures contained distinct and taxonomically largely novel microbial communities. At the trawled site we recorded significant quantitative differences in distinct microbial phyla, such as a reduction in Nitrospinae in the four sponges from this site and the environmental references. Individuals of V. pourtalesii growing on the mooring were significantly enriched in Bacteroidetes, Verrucomicrobia and Cyanobacteria in comparison to sponge individuals growing on the natural seabed. Due to a concomitant enrichment of these taxa in the mooring biofilm, we propose that biofilms on artificial substrates may ‘prime’ sponge-associated microbial communities when small sponges settle on such substrates. These observations likely have relevant management implications when considering the increase of artificial substrates in the marine environment, e.g., marine litter, off-shore wind parks, and petroleum platforms.


2018 ◽  
Author(s):  
Davies Kiambi Kaimenyi ◽  
Etienne P De Villiers ◽  
Joyce Ngoi ◽  
James B Ndiso ◽  
Santie M De Villiers

Background. Metagenomics studies have reported on the complexity of microbiomes associated with seagrass and can provide critical insights into the sustainable use and conservation of seagrasses. Recent conservation activities in Kenya focused mainly on coral reefs and mangrove forests with little direct action taken to conserve seagrass meadows. Pollution, over-exploitation of marine resources and minimal efforts towards enforcement of conservation laws of marine environments, have caused degradation and defoliation of seagrass habitats. Little is known about the microbes associated with seagrass species in Kenya and this study aimed to characterize the genetic diversity of the microbiomes of two prominent seagrass species, Enhalus acoroides and Thallasodendron ciliatum, which are the most commonly occurring species. Methods. Replicate microbiome samples were collected from leaves, roots, sediment and water columns associated with the two seagrass species from two sites on the Kenyan coast. The microbial communities of the samples were characterized and compared using 16S ribosomal RNA gene PCR and sequencing. Microbiome features including diversity and taxonomic composition were used to compare within and between sample types and sites. Results. Leaf samples from both E. acoroides and T. ciliatum had significantly different microbial communities comparted to root and sediment samples, revealing a diversity gradient with lowest diversity in water samples and highest in sediment. There were no significant variation in seagrass microbial composition associated with leaf and rhizosphere microbiomes of either E. acoroides or T. ciliatum. However, we did see a difference between water samples associated with each seagrass species. Discussion. This study of the microbiomes associated with the sediments, roots, leaves and surrounding water of E. acoroides and T. ciliatum, included a limited number of samples from a small geographic area, providing a valuable first assessment of the microbial diversity of seagrass beds on the Kenyan coast. We found no significant differences between the plant-associated bacterial communities of the two-seagrass species investigated. Significant differences however, were observed amongst leaf-, root-, sediment- and water-associated bacterial communities. This work will contribute to understanding the dynamic environment of seagrass beds and will contribute to helping conserving and re-establishing seagrass beds degraded by due to anthropogenic activities.


Author(s):  
Kathrin Busch ◽  
Lindsay Beazley ◽  
Ellen Kenchington ◽  
Frederick Whoriskey ◽  
Beate Slaby ◽  
...  

ABSTRACTEstablishment of adequate conservation areas represents a challenging but crucial task in the conservation of genetic diversity and biological variability. Anthropogenic pressures on marine ecosystems and organisms are steadily increasing. Whether and to what extent these pressures influence marine genetic biodiversity is only starting to be revealed. Using 16S rRNA gene amplicon sequencing, we analysed the microbial community structure of 33 individuals of the habitat-forming glass sponge Vazella pourtalesii, as well as reference seawater, sediment, and biofilm samples. We assessed how two anthropogenic impacts, i.e. habitat destruction by trawling and artificial substrate provision (moorings made of composite plastic), correspond with in situ V. pourtalesii microbiome variability. In addition, we evaluated the role of two bottom fishery closures in preserving sponge-associated microbial diversity on the Scotian Shelf, Canada. Our results illustrate that V. pourtalesii sponges collected from pristine sites within fishery closures contained distinct and taxonomically largely novel microbial communities. At the trawled site we recorded significant quantitative differences in distinct microbial phyla, such as a reduction in Nitrospinae in sponges and environmental references. Individuals of V. pourtalesii growing on the mooring were significantly enriched in Bacteroidetes, Verrucomicrobia and Cyanobacteria in comparison to sponge individuals growing on the natural seabed. Due to a concomitant enrichment of these taxa in the mooring biofilm, we propose that biofilms on artificial substrates may ‘prime’ sponge-associated microbial communities when small sponges settle on such substrates. These observations likely have relevant management implications when considering the increase of artificial substrates in the marine environment, e.g., marine litter, off-shore wind parks, and petroleum platforms.


Author(s):  
James Skelton ◽  
Kevin M Geyer ◽  
Jay T Lennon ◽  
Robert P Creed ◽  
Bryan L Brown

Communities of symbiotic microbes obtained from the environment are an integral component of animal fitness and ecology. Thus a general and practical understanding of the processes that drive microbiome assembly and structure are paramount to understanding animal ecology, health, and evolution. We conceptualized a series of ecological filters that operate at the environment, host, and host tissue levels during microbiome assembly and discuss key ecological processes that structure animal microbiomes at each level. We conducted a survey of crayfish across four sites within the contiguous range of the of stream-inhabiting crayfish Cambarus sciotensis in western Virginia, USA, to characterize multiscale variation in the crayfish microbiome. We also conducted an in situ experiment to assess local drivers of microbial diversity on the closely related Cambarus chasmodactylus. We used a combination of DNA fingerprinting and next-generation sequencing to characterize microbiome diversity and composition from crayfish carapaces and gills to identify key filters affecting microbiome structure. Field survey showed that local environment and host tissues interact to create patterns of microbial diversity and composition, but the strongest effects on microbial community structure were observed at the level of host tissue. Our field experiment confirmed strong effects of host tissue, and also showed that a metazoan ectosymbiont which feeds on biofilms (Annelida; Branchiobdellida) had significant effects on microbial composition of the host carapace. Crayfish carapaces were colonized by diverse and taxonomically even microbial communities that were similar to, and correlated with, microbial communities of the ambient environment. Conversely, crayfish gills were colonized by less diverse communities and dominated by two families of bacteria with potentially significant functional roles: Comamonadaceae and Chitinophagaceae. Our results suggest that microbial assembly of the carapace is driven by external biotic and abiotic processes, whereas assembly on the gills appears to be coupled to host biology that favors interactions with few specific taxa. Our work shows how multi-scale studies of symbiont community assembly provide valuable insights into how the animal microbiome is structured under conditions of natural complexity and help identify other symbiont taxa, i.e., the branchiobdellidans, that may further influence microbiome assembly and structure.


2016 ◽  
Author(s):  
James Skelton ◽  
Kevin M Geyer ◽  
Jay T Lennon ◽  
Robert P Creed ◽  
Bryan L Brown

Communities of symbiotic microbes obtained from the environment are an integral component of animal fitness and ecology. Thus a general and practical understanding of the processes that drive microbiome assembly and structure are paramount to understanding animal ecology, health, and evolution. We conceptualized a series of ecological filters that operate at the environment, host, and host tissue levels during microbiome assembly and discuss key ecological processes that structure animal microbiomes at each level. We conducted a survey of crayfish across four sites within the contiguous range of the of stream-inhabiting crayfish Cambarus sciotensis in western Virginia, USA, to characterize multiscale variation in the crayfish microbiome. We also conducted an in situ experiment to assess local drivers of microbial diversity on the closely related Cambarus chasmodactylus. We used a combination of DNA fingerprinting and next-generation sequencing to characterize microbiome diversity and composition from crayfish carapaces and gills to identify key filters affecting microbiome structure. Field survey showed that local environment and host tissues interact to create patterns of microbial diversity and composition, but the strongest effects on microbial community structure were observed at the level of host tissue. Our field experiment confirmed strong effects of host tissue, and also showed that a metazoan ectosymbiont which feeds on biofilms (Annelida; Branchiobdellida) had significant effects on microbial composition of the host carapace. Crayfish carapaces were colonized by diverse and taxonomically even microbial communities that were similar to, and correlated with, microbial communities of the ambient environment. Conversely, crayfish gills were colonized by less diverse communities and dominated by two families of bacteria with potentially significant functional roles: Comamonadaceae and Chitinophagaceae. Our results suggest that microbial assembly of the carapace is driven by external biotic and abiotic processes, whereas assembly on the gills appears to be coupled to host biology that favors interactions with few specific taxa. Our work shows how multi-scale studies of symbiont community assembly provide valuable insights into how the animal microbiome is structured under conditions of natural complexity and help identify other symbiont taxa, i.e., the branchiobdellidans, that may further influence microbiome assembly and structure.


2021 ◽  
Author(s):  
Liping Qiu ◽  
Weibo Kong ◽  
Hansong Zhu ◽  
Qian Zhang ◽  
Samiran Banerjee ◽  
...  

Abstract Background: Salinization is an important global environmental problem influencing sustainable development of terrestrial ecosystems. Salt-tolerant halophytes are often used as a promising approach to remedy the saline soils. Yet, how halophytes affect rhizosphere microbial diversity, and microbes’ association and functions in saline ecosystems remains unclear, restricting our ability to assess plant fitness to salt stress and to remediate saline ecosystems. Herein, we examined bacterial and fungal diversities, compositions, and co-occurrence networks in the rhizospheres of six halophytes and bulk soils in a semiarid inland saline ecosystem. We also established the relationship of microbial structure and network complexity to microbial functions.Results: The microbial communities in rhizospheres were more diverse and complex than those the bulk soils. The connections of taxa in the rhizosphere microbial communities increased with fungi-fungi and bacteria-fungi connections and fungal diversity, but decreased with bacteria-bacteria connections and bacterial diversity. The proportion of the fungi-related central connections were larger in the rhizospheres (13-73%) than the bulk soils (3%). Additionally, fungi accounted for 27-63% of the keystone taxa identified in the microbial co-occurrence networks present in the rhizospheres, whereas the keystone taxa identified in the bulk soils were all bacteria/archaea. Moreover, microbial activity and residues were significantly higher in the halophyte rhizospheres than the bulk soils, and were significantly correlated with microbial composition and co-occurrence network complexity.Conclusions: These results indicated that halophytes shaped rhizosphere microbiomes and increased microbial diversity and network complexity in inland saline ecosystem, while fungi enhanced rhizosphere microbiota associations. The increased microbial network complexity contributed to the higher microbial functions in rhizosphere soils.


2018 ◽  
Author(s):  
Davies Kiambi Kaimenyi ◽  
Etienne P De Villiers ◽  
Joyce Ngoi ◽  
James B Ndiso ◽  
Santie M De Villiers

Background. Metagenomics studies have reported on the complexity of microbiomes associated with seagrass and can provide critical insights into the sustainable use and conservation of seagrasses. Recent conservation activities in Kenya focused mainly on coral reefs and mangrove forests with little direct action taken to conserve seagrass meadows. Pollution, over-exploitation of marine resources and minimal efforts towards enforcement of conservation laws of marine environments, have caused degradation and defoliation of seagrass habitats. Little is known about the microbes associated with seagrass species in Kenya and this study aimed to characterize the genetic diversity of the microbiomes of two prominent seagrass species, Enhalus acoroides and Thallasodendron ciliatum, which are the most commonly occurring species. Methods. Replicate microbiome samples were collected from leaves, roots, sediment and water columns associated with the two seagrass species from two sites on the Kenyan coast. The microbial communities of the samples were characterized and compared using 16S ribosomal RNA gene PCR and sequencing. Microbiome features including diversity and taxonomic composition were used to compare within and between sample types and sites. Results. Leaf samples from both E. acoroides and T. ciliatum had significantly different microbial communities comparted to root and sediment samples, revealing a diversity gradient with lowest diversity in water samples and highest in sediment. There were no significant variation in seagrass microbial composition associated with leaf and rhizosphere microbiomes of either E. acoroides or T. ciliatum. However, we did see a difference between water samples associated with each seagrass species. Discussion. This study of the microbiomes associated with the sediments, roots, leaves and surrounding water of E. acoroides and T. ciliatum, included a limited number of samples from a small geographic area, providing a valuable first assessment of the microbial diversity of seagrass beds on the Kenyan coast. We found no significant differences between the plant-associated bacterial communities of the two-seagrass species investigated. Significant differences however, were observed amongst leaf-, root-, sediment- and water-associated bacterial communities. This work will contribute to understanding the dynamic environment of seagrass beds and will contribute to helping conserving and re-establishing seagrass beds degraded by due to anthropogenic activities.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10995
Author(s):  
Muhammad Yasir ◽  
Arooj K. Qureshi ◽  
Esam I. Azhar

Microorganisms in geothermal springs can offer insights into the fundamental and applied study of extremophiles. However, low microbial abundance and culturing requirements limit the ability to analyze microbial diversity in these ecosystems. In this study, culture-dependent and culture-independent techniques were used to analyze sediment samples from the non-volcanic Tatta Pani hot springs in district Poonch of Azad Kashmir. Microbial composition, temperature gradient, and enrichment effects on rare taxa were evaluated. In total, 31 distinct bacterial phyla and 725 genera were identified from the non-enriched Tatta Pani hot spring sediment samples, and 33 distinct bacterial phyla and 890 genera from the enriched sediment samples. Unique phyla specimens from the enriched samples included Candidatus Cloacimonetes, Caldiserica, and Korarchaeota archaea. The enriched samples yielded specific microbiota including 805 bacteria and 42 archaea operational taxonomic units with 97% similarity, though decreased thermophilic microbiota were observed in the enriched samples. Microbial diversity increased as temperature decreased. Candidate novel species were isolated from the culture-dependent screening, along with several genera that were not found in the 16S amplicon sequencing data. Overall, the enriched sediments showed high microbial diversity but with adverse changes in the composition of relatively dominant bacteria. Metagenomic analyses are needed to study the diversity, phylogeny, and functional investigation of hot spring microbiota.


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