scholarly journals Investigating variability in microbial community composition in replicate environmental DNA samples down lake sediment cores

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0250783
Author(s):  
John K. Pearman ◽  
Georgia Thomson-Laing ◽  
Jamie D. Howarth ◽  
Marcus J. Vandergoes ◽  
Lucy Thompson ◽  
...  
Keyword(s):  
16S Rrna ◽  
Sediment Cores ◽  
Microbial Community Composition ◽  
Environmental Dna ◽  
Scaling Analysis ◽  
Biological Communities ◽  
Accumulation Curves ◽  
Community Dissimilarity ◽  
Sample Heterogeneity ◽  
Read Abundance

Lake sediments are natural archives that accumulate information on biological communities and their surrounding catchments. Paleolimnology has traditionally focussed on identifying fossilized organisms to reconstruct past environments. In the last decade, the application of molecular methodologies has increased in paleolimnological studies, but further research investigating factors such as sample heterogeneity and DNA degradation are required. In the present study we investigated bacterial community heterogeneity (16S rRNA metabarcoding) within depth slices (1-cm width). Sediment cores were collected from three lakes with differing sediment compositions. Samples were collected from a variety of depths which represent a period of time of approximately 1,200 years. Triplicate samples were collected from each depth slice and bacterial 16S rRNA metabarcoding was undertaken on each sample. Accumulation curves demonstrated that except for the deepest (oldest) slices, the combination of three replicate samples were insufficient to characterise the entire bacterial diversity. However, shared Amplicon Sequence Variants (ASVs) accounted for the majority of the reads in each depth slice (max. shared proportional read abundance 96%, 86%, 65% in the three lakes). Replicates within a depth slice generally clustered together in the Non-metric multidimensional scaling analysis. There was high community dissimilarity in older sediment in one of the cores, which was likely due to the laminae in the sediment core not being horizontal. Given that most paleolimnology studies explore broad scale shifts in community structure rather than seeking to identify rare species, this study demonstrates that a single sample is adequate to characterise shifts in dominant bacterial ASVs.

scholarly journals Environmental DNA variability in lake sediment cores

2021 ◽  
Vol 4 ◽  
Author(s):  
John Pearman ◽  
Georgia Thomson-Laing ◽  
Jamie Howarth ◽  
Marcus Vandergoes ◽  
Lucy Thompson ◽  
...  
Keyword(s):  
16S Rrna ◽  
General Trend ◽  
Sediment Cores ◽  
Environmental Dna ◽  
Biological Communities ◽  
The Core ◽  
Community Dissimilarity ◽  
Sample Heterogeneity ◽  
Read Abundance ◽  
Natural Archives

Lake sediments are natural archives that accumulate information about biological communities and their surrounding catchments. Paleolimnology has traditionally focussed on identifying fossilized organisms to reconstruct past environments. In the last decade, the application of molecular methodologies has increased in paleolimnological studies, but further studies investigating factors such as sample heterogeneity and DNA degradation are required. Here we investigated bacterial community heterogeneity (16S rRNA metabarcoding) within depth slices. Sediment cores were collected from three lakes with differing sediment compositions. Samples were collected from a variety of depths (1-cm width) which represent a period of time of approximately 1,200 years. Triplicate samples were collected from each slice and bacterial 16S rRNA metabarcoding was undertaken on each sample. Rarefaction curves showed that except for the deepest (oldest) slices, the combination of three replicate samples were insufficient to characterise the entire bacterial diversity. However, shared Amplicon Sequence Variants (ASVs) accounted for the majority of the reads in each slice (max. shared proportional read abundance 96%, 86%, 65% in the three lakes). Within slice similarity was higher than between slice similarity. No general trend was observed in variability among replicates with depth amongst the lakes. In one core. there was a higher community dissimilarity in older sediment, which may be due to laminae not being horizontal. These results highlight the fact that microbial communities can be differentiated with depth however it is critical to interpret these results in the context of the stratigraphic data of the core.

scholarly journals Environmental DNA preserved in marine sediment for detecting jellyfish blooms after a tsunami

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mizuki Ogata ◽  
Reiji Masuda ◽  
Hiroya Harino ◽  
Masayuki K. Sakata ◽  
Makoto Hatakeyama ◽  
...  
Keyword(s):  
Marine Sediment ◽  
Oil Spills ◽  
Sediment Cores ◽  
Environmental Dna ◽  
Target Species ◽  
Tank Experiment ◽  
Polycyclic Aromatic ◽  
Flow Through ◽  
High Concentrations ◽  
One Year

AbstractEnvironmental DNA (eDNA) can be a powerful tool for detecting the distribution and abundance of target species. This study aimed to test the longevity of eDNA in marine sediment through a tank experiment and to use this information to reconstruct past faunal occurrence. In the tank experiment, juvenile jack mackerel (Trachurus japonicus) were kept in flow-through tanks with marine sediment for two weeks. Water and sediment samples from the tanks were collected after the removal of fish. In the field trial, sediment cores were collected in Moune Bay, northeast Japan, where unusual blooms of jellyfish (Aurelia sp.) occurred after a tsunami. The samples were analyzed by layers to detect the eDNA of jellyfish. The tank experiment revealed that after fish were removed, eDNA was not present in the water the next day, or subsequently, whereas eDNA was detectable in the sediment for 12 months. In the sediment core samples, jellyfish eDNA was detected at high concentrations above the layer with the highest content of polycyclic aromatic hydrocarbons, reflecting tsunami-induced oil spills. Thus, marine sediment eDNA preserves a record of target species for at least one year and can be used to reconstruct past faunal occurrence.

scholarly journals Evaluation of the microbial community structure of potable water samples from occupied and unoccupied buildings using16S rRNA amplicon sequencing

2020 ◽  
Author(s):  
Kimothy L Smith ◽  
Howard A Shuman ◽  
Douglas Findeisen
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
Water Samples ◽  
Ad Hoc ◽  
Microbial Community Composition ◽  
Amplicon Sequencing ◽  
The Other ◽  
Water Usage ◽  
16S Rrna Amplicon Sequencing ◽  
Oxford Nanopore

AbstractWe conducted two studies of water samples from buildings with normal occupancy and water usage compared to water from buildings that were unoccupied with little or no water usage due to the COVID-19 shutdown. Study 1 had 52 water samples obtained ad hoc from buildings in four metropolitan locations in different states in the US and a range of building types. Study 2 had 36 water samples obtained from two buildings in one metropolitan location with matched water sample types. One of the buildings had been continuously occupied, and the other substantially vacant for approximately 3 months. All water samples were analyzed using 16S rRNA amplicon sequencing with a MinION from Oxford Nanopore Technologies. More than 127 genera of bacteria were identified, including genera with members that are known to include more than 50 putative frank and opportunistic pathogens. While specific results varied among sample locations, 16S rRNA amplicon abundance and the diversity of bacteria were higher in water samples from unoccupied buildings than normally occupied buildings as was the abundance of sequenced amplicons of genera known to include pathogenic bacterial members. In both studies Legionella amplicon abundance was relatively small compared to the abundance of the other bacteria in the samples. Indeed, when present, the relative abundance of Legionella amplicons was lower in samples from unoccupied buildings. Legionella did not predominate in any of the water samples and were found, on average, in 9.6% of samples in Study 1 and 8.3% of samples in Study 2.SynopsisComparison of microbial community composition in the plumbing of occupied and unoccupied buildings during the COVID-19 pandemic shutdown.

scholarly journals Changes in the Active, Dead, and Dormant Microbial Community Structure across a Pleistocene Permafrost Chronosequence

2019 ◽  
Vol 85 (7) ◽  
Author(s):  
Alexander Burkert ◽  
Thomas A. Douglas ◽  
Mark P. Waldrop ◽  
Rachel Mackelprang
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Communities ◽  
Community Composition ◽  
Environmental Conditions ◽  
Microbial Community Composition ◽  
Rrna Gene ◽  
Subzero Temperatures ◽  
Dormant Cells

ABSTRACTPermafrost hosts a community of microorganisms that survive and reproduce for millennia despite extreme environmental conditions, such as water stress, subzero temperatures, high salinity, and low nutrient availability. Many studies focused on permafrost microbial community composition use DNA-based methods, such as metagenomics and 16S rRNA gene sequencing. However, these methods do not distinguish among active, dead, and dormant cells. This is of particular concern in ancient permafrost, where constant subzero temperatures preserve DNA from dead organisms and dormancy may be a common survival strategy. To circumvent this, we applied (i) LIVE/DEAD differential staining coupled with microscopy, (ii) endospore enrichment, and (iii) selective depletion of DNA from dead cells to permafrost microbial communities across a Pleistocene permafrost chronosequence (19,000, 27,000, and 33,000 years old). Cell counts and analysis of 16S rRNA gene amplicons from live, dead, and dormant cells revealed how communities differ between these pools, how they are influenced by soil physicochemical properties, and whether they change over geologic time. We found evidence that cells capable of forming endospores are not necessarily dormant and that members of the classBacilliwere more likely to form endospores in response to long-term stressors associated with permafrost environmental conditions than members of theClostridia, which were more likely to persist as vegetative cells in our older samples. We also found that removing exogenous “relic” DNA preserved within permafrost did not significantly alter microbial community composition. These results link the live, dead, and dormant microbial communities to physicochemical characteristics and provide insights into the survival of microbial communities in ancient permafrost.IMPORTANCEPermafrost soils store more than half of Earth’s soil carbon despite covering ∼15% of the land area (C. Tarnocai et al., Global Biogeochem Cycles 23:GB2023, 2009, https://doi.org/10.1029/2008GB003327). This permafrost carbon is rapidly degraded following a thaw (E. A. G. Schuur et al., Nature 520:171–179, 2015, https://doi.org/10.1038/nature14338). Understanding microbial communities in permafrost will contribute to the knowledge base necessary to understand the rates and forms of permafrost C and N cycling postthaw. Permafrost is also an analog for frozen extraterrestrial environments, and evidence of viable organisms in ancient permafrost is of interest to those searching for potential life on distant worlds. If we can identify strategies microbial communities utilize to survive in permafrost, it may yield insights into how life (if it exists) survives in frozen environments outside of Earth. Our work is significant because it contributes to an understanding of how microbial life adapts and survives in the extreme environmental conditions in permafrost terrains.

Retrieval of nearly complete 16S rRNA gene sequences from environmental DNA following 16S rRNA-based community fingerprinting

2005 ◽  
Vol 7 (5) ◽  
pp. 670-675 ◽  
Author(s):  
Manfred G. Hofle ◽  
Sebastien Flavier ◽  
Richard Christen ◽  
Julia Botel ◽  
Matthias Labrenz ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Environmental Dna ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Community Fingerprinting

scholarly journals Estimating Population Turnover Rates by Relative Quantification Methods Reveals Microbial Dynamics in Marine Sediment

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Richard Kevorkian ◽  
Jordan T. Bird ◽  
Alexander Shumaker ◽  
Karen G. Lloyd
Keyword(s):  
Population Dynamics ◽  
Microbial Community ◽  
16S Rrna ◽  
Sulfate Reduction ◽  
Relative Quantification ◽  
Turnover Rates ◽  
Content Type ◽  
Sulfate Reducing ◽  
Population Turnover ◽  
Read Abundance

ABSTRACT The difficulty involved in quantifying biogeochemically significant microbes in marine sediments limits our ability to assess interspecific interactions, population turnover times, and niches of uncultured taxa. We incubated surface sediments from Cape Lookout Bight, North Carolina, USA, anoxically at 21°C for 122 days. Sulfate decreased until day 68, after which methane increased, with hydrogen concentrations consistent with the predicted values of an electron donor exerting thermodynamic control. We measured turnover times using two relative quantification methods, quantitative PCR (qPCR) and the product of 16S gene read abundance and total cell abundance (FRAxC, which stands for “fraction of read abundance times cells”), to estimate the population turnover rates of uncultured clades. Most 16S rRNA reads were from deeply branching uncultured groups, and ∼98% of 16S rRNA genes did not abruptly shift in relative abundance when sulfate reduction gave way to methanogenesis. Uncultured Methanomicrobiales and Methanosarcinales increased at the onset of methanogenesis with population turnover times estimated from qPCR at 9.7 ± 3.9 and 12.6 ± 4.1 days, respectively. These were consistent with FRAxC turnover times of 9.4 ± 5.8 and 9.2 ± 3.5 days, respectively. Uncultured Syntrophaceae, which are possibly fermentative syntrophs of methanogens, and uncultured Kazan-3A-21 archaea also increased at the onset of methanogenesis, with FRAxC turnover times of 14.7 ± 6.9 and 10.6 ± 3.6 days. Kazan-3A-21 may therefore either perform methanogenesis or form a fermentative syntrophy with methanogens. Three genera of sulfate-reducing bacteria, Desulfovibrio, Desulfobacter, and Desulfobacterium, increased in the first 19 days before declining rapidly during sulfate reduction. We conclude that population turnover times on the order of days can be measured robustly in organic-rich marine sediment, and the transition from sulfate-reducing to methanogenic conditions stimulates growth only in a few clades directly involved in methanogenesis, rather than in the whole microbial community. IMPORTANCE Many microbes cannot be isolated in pure culture to determine their preferential growth conditions and predict their response to changing environmental conditions. We created a microcosm of marine sediments that allowed us to simulate a diagenetic profile using a temporal analog for depth. This allowed for the observation of the microbial community population dynamics caused by the natural shift from sulfate reduction to methanogenesis. Our research provides evidence for the population dynamics of uncultured microbes as well as the application of a novel method of turnover rate analysis for individual taxa within a mixed incubation, FRAxC, which stands for “fraction of read abundance times cells,” which was verified by quantitative PCR. This allows for the calculation of population turnover times for microbes in a natural setting and the identification of uncultured clades involved in geochemical processes.

Organotrophic and Mixotrofic Sulfur Oxidation in an Acidic Salt Flat in Northern Chile

2015 ◽  
Vol 1130 ◽  
pp. 63-66 ◽  
Author(s):  
Lorena Escudero ◽  
Jonathan Bijman ◽  
Guajardo M. Mariela ◽  
Juan José Pueyo Mur ◽  
Guillermo Chong ◽  
...  
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Community Composition ◽  
Iron Concentration ◽  
Rrna Gene ◽  
Salt Flat ◽  
Significant Difference ◽  
Acidic Salt ◽  
The 16S Rrna Gene

To understand the microbial community inhabiting in an acidic salt flat the phylogenetic diversity and the geochemistry of this system was compared to acid mine drainage (AMD) systems. The microbial community structure was assessed by DNA extraction/PCR/DGGE and secuencing for the 16S rRNA gene and the geochemistry was analyzed using several approaches. Prediction of metagenome functional content was performed from the 16S rRNA gene survey using the bioinformatics software package Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). The geochemical results revealed a much lower iron concentration in the salt flat than in AMD systems (39 and 21804 mg L-1, respectively) and a significant difference in chloride levels. Sequences inferred to be from potential sulfur metabolizing organisms constituted up to 70% of the microbial community in the acidic salt flat meanwhile predominat iron-metabolizing acidophile populations were reported in AMD systems. Interestingly, the microbial assemblage in the acidic salt flat was dominated by mixotrophic and organotrophic sulfur oxidizers as well as by photoautotrophic acidophiles. Our results suggests that the salt concentration in Salar de Gorbea (average Cl-= 40 gL-1) is in the limit for the occurrence of chemolithotrophic oxidation of sulfur compounds. In addition, the investigation allows concluding that salinity rather than extremes of pH is the major environmental determinant of microbial community composition.

scholarly journals Integration of Microbial Ecology and Statistics: a Test To Compare Gene Libraries

2004 ◽  
Vol 70 (9) ◽  
pp. 5485-5492 ◽  
Author(s):  
Patrick D. Schloss ◽  
Bret R. Larget ◽  
Jo Handelsman
Keyword(s):  
16S Rrna ◽  
Microbial Community Composition ◽  
Integral Form ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Soil Productivity ◽  
Pairwise Comparisons ◽  
Rrna Gene ◽  
Ecological Inference ◽  
Gene Libraries

ABSTRACT Libraries of 16S rRNA genes provide insight into the membership of microbial communities. Statistical methods help to determine whether differences in library composition are artifacts of sampling or are due to underlying differences in the communities from which they are derived. To contribute to a growing statistical framework for comparing 16S rRNA libraries, we present a computer program, ∫-LIBSHUFF, which calculates the integral form of the Cramér-von Mises statistic. This implementation builds upon the LIBSHUFF program, which uses an approximation of the statistic and makes a number of modifications that improve precision and accuracy. Once ∫-LIBSHUFF calculates the P values, when pairwise comparisons are tested at the 0.05 level, the probability of falsely identifying a significant P value is 0.098 for a study with two libraries, 0.265 for three libraries, and 0.460 for four libraries. The potential negative effects of making the multiple pairwise comparisons necessitate correcting for the increased likelihood that differences between treatments are due to chance and do not reflect biological differences. Using ∫-LIBSHUFF, we found that previously published 16S rRNA gene libraries constructed from Scottish and Wisconsin soils contained different bacterial lineages. We also analyzed the published libraries constructed for the zebrafish gut microflora and found statistically significant changes in the community during development of the host. These analyses illustrate the power of ∫-LIBSHUFF to detect differences between communities, providing the basis for ecological inference about the association of soil productivity or host gene expression and microbial community composition.

scholarly journals MAUI-seq: Metabarcoding using amplicons with unique molecular identifiers to improve error correction

2019 ◽  
Author(s):  
Bryden Fields ◽  
Sara Moeskjær ◽  
Ville-Petri Friman ◽  
Stig U. Andersen ◽  
J. Peter W. Young
Keyword(s):  
Genetic Diversity ◽  
16S Rrna ◽  
Error Correction ◽  
High Throughput ◽  
Environmental Dna ◽  
Amplicon Sequencing ◽  
Efficient Elimination

AbstractBackgroundSequencing and PCR errors are a major challenge when characterising genetic diversity using high-throughput amplicon sequencing (HTAS).ResultsWe have developed a multiplexed HTAS method, MAUI-seq, which uses unique molecular identifiers (UMIs) to improve error correction by exploiting variation among sequences associated with a single UMI. We show that two main advantages of this approach are efficient elimination of chimeric and other erroneous reads, outperforming DADA2 and UNOISE3, and the ability to confidently recognise genuine alleles that are present at low abundance or resemble chimeras.ConclusionsThe method provides sensitive and flexible profiling of diversity and is readily adaptable to most HTAS applications, including microbial 16S rRNA profiling and metabarcoding of environmental DNA.

scholarly journals Microbial composition, diversity, and activity varies across different types of basal ice

2021 ◽  
Author(s):  
Shawn M. Doyle ◽  
Brent C. Christner
Keyword(s):  
Organic Matter ◽  
16S Rrna ◽  
Meta Analysis ◽  
Microbial Composition ◽  
Glacial Ice ◽  
Microbiome Composition ◽  
Basal Ice ◽  
Different Types ◽  
Insight Into ◽  
Read Abundance

ABSTRACTBasal ice often contains entrained subglacial debris and sediment which can serve as a source of nutrients and organic matter and provide habitat for microorganisms adapted to frozen conditions. However, basal ice comes in many different forms and comparatively little is known about how microbial composition, diversity, and activity vary across different types of basal ice. Here, we investigated these parameters in four different types of basal ice from two different glaciers and then used a meta-analysis to compare our findings with microbiome studies of other permanently frozen environments. We found microbiome composition varies substantially between basal ice types, even within the same glacier. Further, the microbiomes of sediment-rich basal ices were distinct from those found in glacial ice and instead were most like those found in permafrost. Consistent with this, microbial diversity was also comparable to that found in permafrost and was much higher relative to glacial ice. Patterns of 16S rRNA read abundance from RNA relative to DNA implicated certain taxa as potentially active in basal ice with ice temperature appearing to be an important predictor for the diversity of taxa inferred to be active. Our results improve our understanding of the microbial ecology of different basal ice types and provide insight into which types are likely habitats for metabolizing microbial communities.

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