scholarly journals Temporal and spatial mediated changes in subsurface microbial community assemblages and functions

2020 ◽  
Author(s):  
Madison C. Davis

Abstract. Groundwater ecosystems can host different habitats with unique microbial assemblages and functions. Although groundwater microbes are important to subsurface processes, little is known about the drivers of change in these communities. Illumina sequencing and bioinformatic tools were used to examine whether different groundwater zones could have the same patterns of microbial community change over a two-year period. Five different groundwater zones from Hospital Hole, a stratified sinkhole in west-central Florida, were used in this study since they have been previously shown to host distinct microbial communities. Seasonal patterns of microbial community assemblages and potential metabolic functions were not identified in the sinkhole communities. Different physicochemical parameters correlated to microbial community change within each zone. Local hydrogeology appears to play an important role in subsurface microbial community change since Hurricane Irma and seasonal turnover events did not appear to cause a large perturbation in the microbial communities. Nutrient availability and local hydrogeochemistry appear to be important drivers of microbial community change in the subsurface.

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 865
Author(s):  
Lantian Su ◽  
Xinxin Liu ◽  
Guangyao Jin ◽  
Yue Ma ◽  
Haoxin Tan ◽  
...  

In recent decades, wild sable (Carnivora Mustelidae Martes zibellina) habitats, which are often natural forests, have been squeezed by anthropogenic disturbances such as clear-cutting, tilling and grazing. Sables tend to live in sloped areas with relatively harsh conditions. Here, we determine effects of environmental factors on wild sable gut microbial communities between high and low altitude habitats using Illumina Miseq sequencing of bacterial 16S rRNA genes. Our results showed that despite wild sable gut microbial community diversity being resilient to many environmental factors, community composition was sensitive to altitude. Wild sable gut microbial communities were dominated by Firmicutes (relative abundance 38.23%), followed by Actinobacteria (30.29%), and Proteobacteria (28.15%). Altitude was negatively correlated with the abundance of Firmicutes, suggesting sable likely consume more vegetarian food in lower habitats where plant diversity, temperature and vegetation coverage were greater. In addition, our functional genes prediction and qPCR results demonstrated that energy/fat processing microorganisms and functional genes are enriched with increasing altitude, which likely enhanced metabolic functions and supported wild sables to survive in elevated habitats. Overall, our results improve the knowledge of the ecological impact of habitat change, providing insights into wild animal protection at the mountain area with hash climate conditions.


Data ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 44
Author(s):  
Jae-Hyun Lim ◽  
Il-Nam Kim

Marine bacteria are known to play significant roles in marine biogeochemical cycles regarding the decomposition of organic matter. Despite the increasing attention paid to the study of marine bacteria, research has been too limited to fully elucidate the complex interaction between marine bacterial communities and environmental variables. Jinhae Bay, the study area in this work, is the most anthropogenically eutrophied coastal bay in South Korea, and while its physical and biogeochemical characteristics are well described, less is known about the associated changes in microbial communities. In the present study, we reconstructed a metagenomics data based on the 16S rRNA gene to investigate temporal and vertical changes in microbial communities at three depths (surface, middle, and bottom) during a seven-month period from June to December 2016 at one sampling site (J1) in Jinhae Bay. Of all the bacterial data, Proteobacteria, Bacteroidetes, and Cyanobacteria were predominant from June to November, whereas Firmicutes were predominant in December, especially at the middle and bottom depths. These results show that the composition of the microbial community is strongly associated with temporal changes. Furthermore, the community compositions were markedly different between the surface, middle, and bottom depths in summer, when water column stratification and bottom water hypoxia (low dissolved oxygen level) were strongly developed. Metagenomics data contribute to improving our understanding of important relationships between environmental characteristics and microbial community change in eutrophication-induced and deoxygenated coastal areas.


2020 ◽  
Author(s):  
Joeselle M. Serrana ◽  
Bin Li ◽  
Tetsuya Sumi ◽  
Yasuhiro Takemon ◽  
Kozo Watanabe

AbstractBackgroundRiver restoration efforts are expected to influence and change the diversity and functions of microbial communities following the recovery of habitat characteristics in the river ecosystem. The recreation or restoration of gravel bars in the Trinity River in California aims to rehabilitate the environmental heterogeneity downstream of the dam impounded channel. Here, we profiled the community composition, estimated diversity, and annotated putative metabolic functions of the sediment microbial communities to assess whether the construction and restoration of gravel bars in the Trinity River in California enhanced environmental heterogeneity, with the increase in the microbial beta diversity of these in-channel structures against the free-flowing reach of the main channel with comparison to its undisturbed tributaries.ResultsMicrobial community composition of the free-flowing (i.e., no gravel bars) communities were relatively closer regardless of dam influence, whereas the Trinity River gravel bar and tributaries’ gravel bar communities were highly dissimilar. Proteobacteria, Bacteroidetes, and Acidobacteria were the highly abundant sediment microbial phyla on most sites, specifically in the Trinity River gravel bar communities. Putative functional annotation of microbial taxa revealed that chemoheterotrophy and aerobic chemoheterotrophy were the most prevalent microbial processes, with the Trinity River gravel bars having relatively higher representations. The considerably large abundance of heterotrophic taxa implies that gravel bars provide suitable areas for heterotrophic microorganisms with metabolic functions contributing to the net respiration in the river.ConclusionsOur results provide supporting evidence on the positive impact of habitat restoration being conducted in the Trinity River with the non-dam influenced, undisturbed tributaries as the basis of comparison. Gravel bar recreation and restoration contributed to the increased microbial biodiversity through the restoration of environmental heterogeneity at the river scale. We provided valuable insights into the potential microbial processes in the sediment that might be contributing to the biogeochemical processes carried out by the microbial communities in the Trinity River. The significant positive correlation between the functional diversity of the identified microbial taxa and beta diversity suggests that differences in the detected metabolic functions were closely related to dissimilarities in community composition.


Author(s):  
Zhang-Xian Xie ◽  
Ke-Qiang Yan ◽  
Ling-Fen Kong ◽  
Ying-Bao Gai ◽  
Tao Jin ◽  
...  

AbstractUnderstanding the mechanisms, structuring microbial communities in oligotrophic ocean surface waters remains a major ecological endeavor. Functional redundancy and metabolic tuning are two mechanisms that have been proposed to shape microbial response to environmental forcing. However, little is known about their roles in the oligotrophic surface ocean due to less integrative characterization of community taxonomy and function. Here, we applied an integrated meta-omics-based approach, from genes to proteins, to investigate the microbial community of the oligotrophic northern Indian Ocean. Insignificant spatial variabilities of both genomic and proteomic compositions indicated a stable microbial community that was dominated by Prochlorococcus, Synechococcus, and SAR11. However, fine tuning of some metabolic functions that are mainly driven by salinity and temperature was observed. Intriguingly, a tuning divergence occurred between metabolic potential and activity in response to different environmental perturbations. Our results indicate that metabolic tuning is an important mechanism for sustaining the stability of microbial communities in oligotrophic oceans. In addition, integrated meta-omics provides a powerful tool to comprehensively understand microbial behavior and function in the ocean.


2007 ◽  
Vol 3 (5) ◽  
pp. 487-490 ◽  
Author(s):  
Richard D Bardgett ◽  
Andreas Richter ◽  
Roland Bol ◽  
Mark H Garnett ◽  
Rupert Bäumler ◽  
...  

When glaciers retreat they expose barren substrates that become colonized by organisms, beginning the process of primary succession. Recent studies reveal that heterotrophic microbial communities occur in newly exposed glacial substrates before autotrophic succession begins. This raises questions about how heterotrophic microbial communities function in the absence of carbon inputs from autotrophs. We measured patterns of soil organic matter development and changes in microbial community composition and carbon use along a 150-year chronosequence of a retreating glacier in the Austrian Alps. We found that soil microbial communities of recently deglaciated terrain differed markedly from those of later successional stages, being of lower biomass and higher abundance of bacteria relative to fungi. Moreover, we found that these initial microbial communities used ancient and recalcitrant carbon as an energy source, along with modern carbon. Only after more than 50 years of organic matter accumulation did the soil microbial community change to one supported primarily by modern carbon, most likely from recent plant production. Our findings suggest the existence of an initial stage of heterotrophic microbial community development that precedes autotrophic community assembly and is sustained, in part, by ancient carbon.


Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 972 ◽  
Author(s):  
Madison Davis ◽  
James Garey

Anchialine sinkholes provide insight into coastal aquifer systems and coastal mixing processes. Aquifer microbial community function is usually inferred from hydrochemical information, but there are few direct studies of microbial communities in the Floridan Aquifer. Hospital Hole is a 43 m-deep stratified sinkhole under the Weeki Wachee River, FL, with three distinct brackish layers: a hypoxic layer, a chemocline and a sulfidic anoxic layer. Illumina sequencing and bioinformatic tools were used to reconstruct metabolic functions and interactions of microbial communities in each layer. Each layer appears to originate from different parts of the coastal mixing zone and has a distinct microbial community with unique functions, which are influenced by the respective hydrochemistry. Sulfide oxidation and nitrate reduction are the most abundant functions. Syntrophy between methane oxidizers, methanogens and sulfate reducers is present. Similarities between the hydrochemistry and potential connectivity of Hospital Hole and the Floridan Aquifer coastal mixing zone suggest that microbial communities of Hospital Hole could be a surrogate for the coastal mixing zone of the aquifer in the absence of direct studies. Understanding how groundwater microbial communities react to saltwater intrusion and nutrient flux will be useful in predicting how coastal aquifer regions might react to anthropogenic change.


2021 ◽  
Author(s):  
Teal S Potter ◽  
Amber C Churchill ◽  
William D Bowman ◽  
Brian L Anacker

Purpose: Plants and soil microbes both influence how ecosystems respond to environmental change. Yet, we lack the ability to generalize how plants and soil microbes influence each other in the same or varying soil conditions. This limitation thwarts ecologists' ability to understand and predict effects of environmental changes such and elevated anthropogenic nitrogen (N) deposition. Accordingly, we examined the specificity of plant species' influence on soil microbial community composition. Methods: We tested (1) whether congeneric grass species have unique effects on soil microbial communities, (2) how relative abundances of microbial taxa can be explained by Poa phylogeny, plant traits, and range-wide traits (annual temperature and soil pH), and (3) whether N addition alters associations between Poa species and soil microbes, and (4) whether the magnitude of microbial community change in response to elevated N can be explained by plant growth responses to N. We conducted a greenhouse experiment with seven Poa species and native soils. Results: We found that individual Poa species were associated with different soil fungi but similar soil bacteria. Differences in microbial composition were not attributable to Poa phylogeny, plant traits, or range-wide traits. Nitrogen addition enhanced the unique effects of Poa species on fungal and bacterial community compositions. Conclusion: These results demonstrate how ecological interactions of related plant species vary depending on resource supply, revealing important context dependency for accurately predicting microbially-mediated nutrient cycling and ecosystem responses to changes in nutrient availability.


2021 ◽  
Author(s):  
Ying Liu ◽  
Mengchu Zeng ◽  
Zhe Xie ◽  
Daliang Ning ◽  
Jizhong Zhou ◽  
...  

Abstract Background: Microbial-mediated decomposition of particulate organic matter (POM) during its downward transport from the surface to the deep ocean constitutes a critical component of the global ocean carbon cycle. However, the extent to which hydrostatic pressure affects microbial community structuring and metabolic functions is largely underexplored. Results: In this study, we investigated microbial community succession, phylogenetic and functional diversity, and metabolic capabilities during POM decomposition by particle-attached (PAM) and free-living microorganisms (FLM) under increasing hydrostatic pressures. Diatom-originated 13C-labeled POM was used to incubate surface water microbial communities from the East China Sea (ECS) at pressures of 0.1, 20, and 40 MPa (megapascal). Our results showed that the PAM and FLM communities exhibited contrasting patterns and pressure-dependencies in diversity, richness, and evenness. Microbial assembly was governed predominantly by stochastic processes at low pressure and by deterministic processes at high pressure. Network analysis uncovered the non-randomly structured PAM and FLM communities and clusters of operational taxonomic units (OTUs) that reflected different functional and ecological capacities of the subgroups. Metatranscriptomic analysis revealed that gene expression of known metabolic pathways (carbohydrate, amino acid, and energy production) varied greatly with pressure and between PAM and FLM. Furthermore, the FLM communities maintained higher metabolic activities than the PAM communities at high pressures, indicating the apparent difference in resource utilization capacity and ecological functions of PAM and FLM in different pelagic zones of the ocean. Overall, we demonstrated that marine heterotrophic microbial assemblage patterns were non-random; the PAM were crucial in community structuring, whereas the FLM played more important roles in POM decomposition in the deep. Conclusions: Our results provide detailed insights into and increased mechanistic understanding of the structuring and succession of microbial communities and metabolic functions associated with POM degradation in the pelagic ocean.


2019 ◽  
Vol 85 (15) ◽  
Author(s):  
Renxing Liang ◽  
Maggie Lau ◽  
Tatiana Vishnivetskaya ◽  
Karen G. Lloyd ◽  
Wei Wang ◽  
...  

ABSTRACTThe prevalence of microbial life in permafrost up to several million years (Ma) old has been well documented. However, the long-term survivability, evolution, and metabolic activity of the entombed microbes over this time span remain underexplored. We integrated aspartic acid (Asp) racemization assays with metagenomic sequencing to characterize the microbial activity, phylogenetic diversity, and metabolic functions of indigenous microbial communities across a ∼0.01- to 1.1-Ma chronosequence of continuously frozen permafrost from northeastern Siberia. Although Asp in the older bulk sediments (0.8 to 1.1 Ma) underwent severe racemization relative to that in the youngest sediment (∼0.01 Ma), the much lowerd-Asp/l-Asp ratio (0.05 to 0.14) in the separated cells from all samples suggested that indigenous microbial communities were viable and metabolically active in ancient permafrost up to 1.1 Ma. The microbial community in the youngest sediment was the most diverse and was dominated by the phylaActinobacteriaandProteobacteria. In contrast, microbial diversity decreased dramatically in the older sediments, and anaerobic, spore-forming bacteria withinFirmicutesbecame overwhelmingly dominant. In addition to the enrichment of sporulation-related genes, functional genes involved in anaerobic metabolic pathways such as fermentation, sulfate reduction, and methanogenesis were more abundant in the older sediments. Taken together, the predominance of spore-forming bacteria and associated anaerobic metabolism in the older sediments suggest that a subset of the original indigenous microbial community entrapped in the permafrost survived burial over geological time.IMPORTANCEUnderstanding the long-term survivability and associated metabolic traits of microorganisms in ancient permafrost frozen millions of years ago provides a unique window into the burial and preservation processes experienced in general by subsurface microorganisms in sedimentary deposits because of permafrost’s hydrological isolation and exceptional DNA preservation. We employed aspartic acid racemization modeling and metagenomics to determine which microbial communities were metabolically active in the 1.1-Ma permafrost from northeastern Siberia. The simultaneous sequencing of extracellular and intracellular genomic DNA provided insight into the metabolic potential distinguishing extinct from extant microorganisms under frozen conditions over this time interval. This in-depth metagenomic sequencing advances our understanding of the microbial diversity and metabolic functions of extant microbiomes from early Pleistocene permafrost. Therefore, these findings extend our knowledge of the survivability of microbes in permafrost from 33,000 years to 1.1 Ma.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicholas C. Dove ◽  
Margaret S. Torn ◽  
Stephen C. Hart ◽  
Neslihan Taş

AbstractIncreasing global temperatures are predicted to stimulate soil microbial respiration. The direct and indirect impacts of warming on soil microbes, nevertheless, remain unclear. This is particularly true for understudied subsoil microbes. Here, we show that 4.5 years of whole-profile soil warming in a temperate mixed forest results in altered microbial community composition and metabolism in surface soils, partly due to carbon limitation. However, microbial communities in the subsoil responded differently to warming than in the surface. Throughout the soil profile—but to a greater extent in the subsoil—physiologic and genomic measurements show that phylogenetically different microbes could utilize complex organic compounds, dampening the effect of altered resource availability induced by warming. We find subsoil microbes had 20% lower carbon use efficiencies and 47% lower growth rates compared to surface soils, which constrain microbial communities. Collectively, our results show that unlike in surface soils, elevated microbial respiration in subsoils may continue without microbial community change in the near-term.


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