scholarly journals Graphene oxide affects soil bacterial and fungal diversity even at parts-per-trillion concentrations

2019 ◽  
Author(s):  
Christian Forstner ◽  
Thomas G. Orton ◽  
Adam Skarshewski ◽  
Peng Wang ◽  
Peter M. Kopittke ◽  
...  

AbstractGraphene oxide (GO) is an oxidized form of graphene that is relatively cheap and easy to produce. This has heralded its widespread use in a range of industries, with its likelihood of release into the environment increasing accordingly. In pure culture, GO has been shown to influence bacteria and fungi, but its effects on environmental microbial communities remain poorly characterized, despite the important ecosystem services that these organisms underpin. Here, we characterized the effects of GO and graphite, over time and at three concentrations (1 ng, 1 µg and 1 mg kg dry soil-1), on soil bacterial and fungal diversity using 16S rRNA and ITS2 gene amplicon sequencing. Graphite was included as a reference material as it is widely distributed in the environment. Neither GO or graphite had significant effects on the alpha diversity of microbial communities. The composition of bacterial and fungal communities, however, was significantly influenced by GO and graphite. These effects were equally apparent between doses and varied over time. Predicted KEGG pathways and fungal guild structures were not significantly influenced by the treatments. Our study demonstrates that GO can influence soil microbial diversity, even at parts-per-trillion concentration, which is equivalent to the rates of release predicted for similar nanomaterials such as carbon nanotubes.ImportanceGraphene oxide is a nanomaterial with broad and expanding industrial applications. Some evidence indicates that it can influence the growth of microorganisms, many of which support important ecosystem services, such as the provision of food and clean water. The amount of graphene oxide currently entering soils is not known but is likely to be similar to other nanomaterials, such as carbon nanotubes (i.e. parts-per-trillion to parts-per-billion per year). In this study, we demonstrate that graphene oxide added to soil at these concentrations (or higher) can alter the composition of bacterial and fungal communities. Nonetheless, we found that these changes were of similar magnitude to those associated with the addition of graphite, which is common and occurs naturally in soils. Further research is recommended to determine whether the changes in microbial community composition that we have shown can be induced by graphene oxide, have deleterious consequences for soil health.

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
S. Emilia Hannula ◽  
Anna M. Kielak ◽  
Katja Steinauer ◽  
Martine Huberty ◽  
Renske Jongen ◽  
...  

ABSTRACT Microorganisms are found everywhere and have critical roles in most ecosystems, but compared to plants and animals, little is known about their temporal dynamics. Here, we investigated the temporal stability of bacterial and fungal communities in the soil and how their temporal variation varies between grasses and forb species. We established 30 outdoor mesocosms consisting of six plant monocultures and followed microbial communities for an entire year in these soils. We demonstrate that bacterial communities vary greatly over time and that turnover plays an important role in shaping microbial communities. We further show that bacterial communities rapidly shift from one state to another and that this is related to changes in the relative contribution of certain taxa rather than to extinction. Fungal soil communities are more stable over time, and a large part of the variation can be explained by plant species and by whether they are grasses or forbs. Our findings show that the soil bacterial community is shaped by time, while plant group and plant species-specific effects drive soil fungal communities. This has important implications for plant-soil research and highlights that temporal dynamics of soil communities cannot be ignored in studies on plant-soil feedback and microbial community composition and function. IMPORTANCE Our findings highlight how soil fungal and bacterial communities respond to time, season, and plant species identity. We found that succession shapes the soil bacterial community, while plant species and the type of plant species that grows in the soil drive the assembly of soil fungal communities. Future research on the effects of plants on soil microbes should take into consideration the relative roles of both time and plant growth on creating soil legacies that impact future plants growing in the soil. Understanding the temporal (in)stability of microbial communities in soils will be crucial for predicting soil microbial composition and functioning, especially as plant species compositions will shift with global climatic changes and land-use alterations. As fungal and bacterial communities respond to different environmental cues, our study also highlights that the selection of study organisms to answer specific ecological questions is not trivial and that the timing of sampling can greatly affect the conclusions made from these studies.


2020 ◽  
Vol 97 (1) ◽  
Author(s):  
Mohammad Bayranvand ◽  
Moslem Akbarinia ◽  
Gholamreza Salehi Jouzani ◽  
Javad Gharechahi ◽  
Yahya Kooch ◽  
...  

ABSTRACT The objective of the present study was to evaluate how altitudinal gradients shape the composition of soil bacterial and fungal communities, humus forms and soil properties across six altitude levels in Hyrcanian forests. Soil microbiomes were characterized by sequencing amplicons of selected molecular markers. Soil chemistry and plant mycorrhizal type were the two dominant factors explaining variations in bacterial and fungal diversity, respectively. The lowest altitude level had more favorable conditions for the formation of mull humus and exhibited higher N and Ca contents. These conditions were also associated with a higher proportion of Betaproteobacteria, Acidimicrobia, Acidobacteria and Nitrospirae. Low soil and forest floor quality as well as lower bacterial and fungal diversity characterized higher altitude levels, along with a high proportion of shared bacterial (Thermoleophilia, Actinobacteria and Bacilli) and fungal (Eurotiomycetes and Mortierellomycota) taxa. Beech-dominated sites showed moderate soil quality and high bacterial (Alphaproteobacteria, Acidobacteria, Planctomycetes and Bacteroidetes) and fungal (Basidiomycota) diversity. Particularly, the Basidiomycota were well represented in pure beech forests at an altitude of 1500 m. In fertile and nitrogen rich soils with neutral pH, soil quality decreased along the altitudinal gradient, indicating that microbial diversity and forest floor decomposition were likely constrained by climatic conditions.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8078 ◽  
Author(s):  
Jingjing Li ◽  
Chao Yang

Background Soil aggregate-size classes and microbial communities within the aggregates are important factors regulating the soil organic carbon (SOC) turnover. However, the response of soil bacterial and fungal communities in aggregates to litter decomposition in different aggregate-size classes is poorly understand. Methods Soil samples from un-grazed natural grassland were separated into four dry aggregate classes of different sizes (2–4 mm, 1–2 mm, 0.25–1 mm and <0.25 mm). Two types of plant litter (leaf and stem) of Leymus chinensis were added to each of the four aggregate class samples. The CO2 release rate, SOC storage and soil microbial communities were measured at the end of the 56-day incubation. Results The results showed that the 1–2 mm aggregate had the highest bacterial Shannon and CO2 release in CK and leaf addition treatments, and the SOC in the <0.25 mm aggregate was higher than that in the others across the treatments. The relative abundance of Ascomycota was higher in the 2–4 mm and <0.25 mm aggregates than in the 1–2 mm and 0.25–1 mm aggregates in the treatment without litter addition, and the relative abundance of Aphelidiomycota was lower in the 2–4 mm and <0.25 mm aggregates than in the 1–2 mm and 0.25–1 mm aggregates. Also, litter addition increased the relative abundance of Proteobacteria and Bacteroidetes, but decreased the relative abundance of Acidobacteria, Gemmatimonadetes, and Actinobacteria. The relative abundance of Ascomycota and Aphelidiomycota increased by more than 10% following leaf litter addition. The bacterial Shannon index had a significantly positive and direct effect on SOC concentration and CO2 release, while the fungal Shannon index was significantly correlated with SOC concentration. Our results indicate that the soil bacterial diversity contributes positively to both carbon emissions and carbon storage, whereas soil fungal diversity can promote carbon storage and decrease carbon emissions.


2019 ◽  
Vol 671 ◽  
pp. 140-148 ◽  
Author(s):  
Christian Forstner ◽  
Thomas G. Orton ◽  
Adam Skarshewski ◽  
Peng Wang ◽  
Peter M. Kopittke ◽  
...  

2019 ◽  
Vol 682 ◽  
pp. 356-363 ◽  
Author(s):  
Christian Forstner ◽  
Thomas G. Orton ◽  
Peng Wang ◽  
Peter M. Kopittke ◽  
Paul G. Dennis

2021 ◽  
Author(s):  
Liping Qiu ◽  
Qian Zhang ◽  
Hansong Zhu ◽  
Peter B. Reich ◽  
Samiran Banerjee ◽  
...  

AbstractWhile soil erosion drives land degradation, the impact of erosion on soil microbial communities and multiple soil functions remains unclear. This hinders our ability to assess the true impact of erosion on soil ecosystem services and our ability to restore eroded environments. Here we examined the effect of erosion on microbial communities at two sites with contrasting soil texture and climates. Eroded plots had lower microbial network complexity, fewer microbial taxa, and fewer associations among microbial taxa, relative to non-eroded plots. Soil erosion also shifted microbial community composition, with decreased relative abundances of dominant phyla such as Proteobacteria, Bacteroidetes, and Gemmatimonadetes. In contrast, erosion led to an increase in the relative abundances of some bacterial families involved in N cycling, such as Acetobacteraceae and Beijerinckiaceae. Changes in microbiota characteristics were strongly related with erosion-induced changes in soil multifunctionality. Together, these results demonstrate that soil erosion has a significant negative impact on soil microbial diversity and functionality.


2018 ◽  
Author(s):  
Jordyn Bergsveinson ◽  
Benjamin J. Perry ◽  
Claudia Sheedy ◽  
Larry Braul ◽  
Sharon Reedyk ◽  
...  

AbstractBacterial and fungal communities of four pesticide rinsate treatment biobeds constructed in Alberta and Saskatchewan, Canada were profiled via high throughput DNA sequencing to assess the effect of biobed depth and pesticide application on microbial community composition. Biobeds differed in geographical location and biobed design, and composition of pesticide rinsates (including herbicides, fungicides, and insecticides). All biobeds achieved similar treatment efficacy and supported greater bacterial diversity relative to fungal diversity, yet selected for similar abundant bacterial orders of Actinomycetales, Acidobacteria, Rhizobiales, and Sphingobacteriales and fungal taxonomic groups of Dothideomycetes, Eurotiales, Hypocreales, and Sordariales. Biobeds differed in the presence of unique and differentiated genera and operational taxonomic units. Biobed depth did not uniformly impact the diversity and/or the microbial community structure. Overall, pesticide application increased bacterial diversity, but had limited effect on the more variable fungal diversity, therefore suggesting broader implication for the effect of applied fungicides on biobed fungal communities.HighlightsBiobeds support diverse bacterial and fungal communitiesSpecific “core” bacterial and fungal taxa are abundant in biobeds of different design and treatmentMicrobial diversity is not directly linked with pesticide type or diversity.


Author(s):  
Sakeenah Adenan ◽  
Jane Oja ◽  
Talaat Abdel-Fattah ◽  
Juha Alatalo

Given the vast expanse of Qatar’s dryland ecosystems, agricultural productivity and soil stability is highly dependent on the diversity of soil microbiota. The soil environment is a heterogeneous habitat shaped by various components like chemical (organic matter, salinity and nutrients) and biological (fungal diversity and vegetation) properties that form multitudes of different microhabitats. Soil microbial diversity changes along environmental gradients. It is hypothesized that a “stable” microhabitat is one that is inhabited by a large diversity of established microorganisms that are best adapted to the niche. Microorganisms like fungi serve as the underlying biological drivers for biochemical processes within the soil. The key objective of this study is to evaluate the fungal diversity and abundance present within the Qatari soil using molecular-based tools and evaluate potential relationships between the identified fungal communities with chemical properties of the habitat. We found that the composition of fungi and AMF varied between different habitats around Qatar. Despite the lack of significant differences in the measured soil chemical parameters between sampled sites, it is evident that AMF species are more abundant than compared to that of other fungal species in most of the study sites; thus, suggesting that other factors like land use may also be an essential component explaining the variation in fungal communities.


2021 ◽  
Vol 87 (6) ◽  
Author(s):  
F. Fracchia ◽  
L. Mangeot-Peter ◽  
L. Jacquot ◽  
F. Martin ◽  
C. Veneault-Fourrey ◽  
...  

ABSTRACT Through their roots, trees interact with a highly complex community of microorganisms belonging to various trophic guilds and contributing to tree nutrition, development, and protection against stresses. Tree roots select for specific microbial species from the bulk soil communities. The root microbiome formation is a dynamic process, but little is known on how the different microorganisms colonize the roots and how the selection occurs. To decipher whether the final composition of the root microbiome is the product of several waves of colonization by different guilds of microorganisms, we planted sterile rooted cuttings of gray poplar obtained from plantlets propagated in axenic conditions in natural poplar stand soil. We analyzed the root microbiome at different time points between 2 and 50 days of culture by combining high-throughput Illumina MiSeq sequencing of the fungal ribosomal DNA internal transcribed spacer and bacterial 16S rRNA amplicons with confocal laser scanning microscopy observations. The microbial colonization of poplar roots took place in three stages, but bacteria and fungi had different dynamics. Root bacterial communities were clearly different from those in the soil after 2 days of culture. In contrast, if fungi were also already colonizing roots after 2 days, the initial communities were very close to that in the soil and were dominated by saprotrophs. They were slowly replaced by endophytes and ectomycorhizal fungi. The replacement of the most abundant fungal and bacterial community members observed in poplar roots over time suggest potential competition effect between microorganisms and/or a selection by the host. IMPORTANCE The tree root microbiome is composed of a very diverse set of bacterial and fungal communities. These microorganisms have a profound impact on tree growth, development, and protection against different types of stress. They mainly originate from the bulk soil and colonize the root system, which provides a unique nutrient-rich environment for a diverse assemblage of microbial communities. In order to better understand how the tree root microbiome is shaped over time, we observed the composition of root-associated microbial communities of naive plantlets of poplar transferred in natural soil. The composition of the final root microbiome relies on a series of colonization stages characterized by the dominance of different fungal guilds and bacterial community members over time. Our observations suggest an early stabilization of bacterial communities, whereas fungal communities are established following a more gradual pattern.


Ecosystems ◽  
2021 ◽  
Author(s):  
Fiona M. Seaton ◽  
Sabine Reinsch ◽  
Tim Goodall ◽  
Nicola White ◽  
Davey L. Jones ◽  
...  

AbstractThe response of soil microbial communities to a changing climate will impact global biogeochemical cycles, potentially leading to positive and negative feedbacks. However, our understanding of how soil microbial communities respond to climate change and the implications of these changes for future soil function is limited. Here, we assess the response of soil bacterial and fungal communities to long-term experimental climate change in a heathland organo-mineral soil. We analysed microbial communities using Illumina sequencing of the 16S rRNA gene and ITS2 region at two depths, from plots undergoing 4 and 18 years of in situ summer drought or warming. We also assessed the colonisation of Calluna vulgaris roots by ericoid and dark septate endophytic (DSE) fungi using microscopy after 16 years of climate treatment. We found significant changes in both the bacterial and fungal communities in response to drought and warming, likely mediated by changes in soil pH and electrical conductivity. Changes in the microbial communities were more pronounced after a longer period of climate manipulation. Additionally, the subsoil communities of the long-term warmed plots became similar to the topsoil. Ericoid mycorrhizal colonisation decreased with depth while DSEs increased; however, these trends with depth were removed by warming. We largely ascribe the observed changes in microbial communities to shifts in plant cover and subsequent feedback on soil physicochemical properties, especially pH. Our results demonstrate the importance of considering changes in soil microbial responses to climate change across different soil depths and after extended periods of time.


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