scholarly journals Response of Soil Microbial Communities to Warming and Clipping in Alpine Meadows in Northern Tibet

2020 ◽  
Vol 12 (14) ◽  
pp. 5617
Author(s):  
Haorui Zhang ◽  
Shaowei Li ◽  
Guangyu Zhang ◽  
Gang Fu
Keyword(s):  
Microbial Communities ◽  
Community Composition ◽  
Soil Microbial Communities ◽  
Alpine Meadows ◽  
Soil Microbial ◽  
Alpine Steppe ◽  
Total Plfa ◽  
Kobresia Meadow ◽  
Low Altitude ◽  
Steppe Meadow

In order to explore responses of soil microbial communities among different alpine meadows under warming and clipping, soil microorganisms of three alpine meadow sites (low altitude: 4313 m, alpine steppe meadow, 30°30′ N, 91°04′ E; mid-altitude: 4513 m, alpine steppe meadow, 30°31′ N, 91°04′ E; and high altitude: 4693, alpine Kobresia meadow, 30°32′ N, 91°03′ E) were measured using the phospholipid fatty acid (PLFA) method. Both warming and clipping significantly reduced PLFA content and changed the community composition of soil microbial taxa, which belong to bacterial and fungal communities in the alpine Kobresia meadow. Warming significantly reduced the soil total PLFA content by 36.1% and the content of soil fungi by 37.0%; the clipping significantly reduced the soil total PLFA content by 57.4%, the content of soil fungi by 49.9%, and the content of soil bacteria by 60.5% in the alpine Kobresia meadow. Only clipping changed the total fungal community composition at a low altitude. Neither clipping nor warming changed the microbial community composition at a moderate altitude. Soil temperature, soil moisture, and pH were the main factors affecting soil microbial communities. Therefore, the effects of warming and clipping on soil microbial communities in alpine meadows were related to grassland types and soil environmental conditions.

scholarly journals Effects of Wildfire and Harvest Disturbances on Forest Soil Bacterial Communities

2007 ◽  
Vol 74 (1) ◽  
pp. 216-224 ◽  
Author(s):  
Nancy R. Smith ◽  
Barbara E. Kishchuk ◽  
William W. Mohn
Keyword(s):  
Microbial Biomass ◽  
Microbial Communities ◽  
Community Composition ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Biomass Carbon ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Rrna Gene ◽  
Microbial Biomass Nitrogen ◽  
Soil Microbial

ABSTRACT Wildfires and harvesting are important disturbances to forest ecosystems, but their effects on soil microbial communities are not well characterized and have not previously been compared directly. This study was conducted at sites with similar soil, climatic, and other properties in a spruce-dominated boreal forest near Chisholm, Alberta, Canada. Soil microbial communities were assessed following four treatments: control, harvest, burn, and burn plus timber salvage (burn-salvage). Burn treatments were at sites affected by a large wildfire in May 2001, and the communities were sampled 1 year after the fire. Microbial biomass carbon decreased 18%, 74%, and 53% in the harvest, burn, and burn-salvage treatments, respectively. Microbial biomass nitrogen decreased 25% in the harvest treatment, but increased in the burn treatments, probably because of microbial assimilation of the increased amounts of available NH4 + and NO3 − due to burning. Bacterial community composition was analyzed by nonparametric ordination of molecular fingerprint data of 119 samples from both ribosomal intergenic spacer analysis (RISA) and rRNA gene denaturing gradient gel electrophoresis. On the basis of multiresponse permutation procedures, community composition was significantly different among all treatments, with the greatest differences between the two burned treatments versus the two unburned treatments. The sequencing of DNA bands from RISA fingerprints revealed distinct distributions of bacterial divisions among the treatments. Gamma- and Alphaproteobacteria were highly characteristic of the unburned treatments, while Betaproteobacteria and members of Bacillus were highly characteristic of the burned treatments. Wildfire had distinct and more pronounced effects on the soil microbial community than did harvesting.

scholarly journals Ammonium and nitrate additions differentially affect soil microbial biomass of different communities and enzyme activities in slash pine plantation in subtropical China

2017 ◽  
Author(s):  
Chuang Zhang ◽  
Xin-Yu Zhang ◽  
Hong-Tao Zou ◽  
Liang Kou ◽  
Yang Yang ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Soil Ph ◽  
Enzyme Activities ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Inhibitory Effects ◽  
Specific Enzyme ◽  
Total N ◽  
Soil Microbial ◽  
Total Plfa

Abstract. The ratios of nitrate to ammonium in wet atmosphere nitrogen (N) deposition compounds were increasing recently. However, the individual effects of nitrate and ammonium deposition on soil microbial communities biomass and enzyme activities are still unclear. We conducted a four-year N addition field experiment to evaluate the responses of soil microbial communities biomass and enzyme activities to ammonium (NH4Cl) and nitrate (NaNO3) additions. Our results showed that (1) the inhibitory effects of ammonium additions on total mass of phospholipid fatty acid (PLFA) were stronger than those of nitrate additions. Both decreased total PLFA mass about 24 % and 11 %, respectively. The inhibitory effects of ammonium additions on gram positive bacteria (G+) and bacteria, fungi, actinomycetes (A), and arbuscular mycorrhizal fungi (AMF) PLFA mass ranged from 14 %–40 %. (2) Both ammonium and nitrate additions inhibited absolute activities of C, N, and P hydrolyses and oxidases, and nitrate additions had stronger inhibition effects on the acid phosphatase (AP) than ammonium additions. Both ammonium and nitrate additions decreased N-acquisition specific enzyme activities (enzyme activities normalized by total PLFA mass) about 21 % or 43 %, respectively. However, ammonium additions increased P-acquisition specific enzyme activities about 19 % comparing to control. (3) Redundancy analysis (RDA) showed that the measured C, N, and P hydrolyses and polyphenol oxidase (PPO) activities were positively correlated with soil pH and ammonium contents, but negatively with nitrate contents; the mass of PLFA biomarkers were positively correlated with soil pH, soil organic carbon (SOC), and total N contents, but negatively with ammonium contents. (4) The soil enzyme activities varied seasonally in the order of March > June > October. On the contrary, microbial PLFA mass was higher in October than in March and June. Our results concluded that inhibition of mass of PLFA biomarkers and enzyme activities might be contributed to acidification caused by ammonium addition. Soil absolute enzyme activities were inhibited indirectly by acidification and nitrification, but specific enzyme activities normalized by PLFA were directly affected by N additions. It was meaningful to separate the effects of ammonium and nitrate additions on soil microbial communities and enzyme activities.

scholarly journals Apple Root stocks and Pre-plant Soil Treatments Alter Soil Microbial Community Composition in a New York Orchard

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1128C-1128
Author(s):  
Shengrui Yao ◽  
Ian A. Merwin ◽  
Janice E. Thies
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Community Composition ◽  
Soil Microbial Community ◽  
Microbial Community Composition ◽  
Soil Microbial Communities ◽  
Growth And Yield ◽  
Soil Microbial ◽  
Plant Soil ◽  
Soil Microbial Community Composition

Apple (Malu ×domestica) replant disease (ARD) is a soil-borne disease syndrome of complex etiology that occurs worldwide when establishing new orchards in old fruit-growing sites. Methyl bromide (MB) has been an effective soil fumigant to control ARD, but safer alternatives to MB are needed. We evaluated soil microbial communities, tree growth, and fruit yield for three pre-plant soil treatments (compost amendment, soil treatment with a broad-spectrum fumigant, and untreated controls), and five clonal rootstocks (M7, M26, CG6210, CG30, and G16), in an apple replant site at Ithaca, N.Y. Molecular fingerprinting (PCR-DGGE) techniques were used to study soil microbial community composition of root-zone soil of the different soil treatments and rootstocks. Tree caliper, shoot growth, and yield were measured annually from 2002–04. Among the five rootstocks we compared, trees on CG6210 had the most growth and yield, while trees on M26 had the least growth and yield. Soil treatments altered soil microbial communities during the year after pre-plant treatments, and each treatment was associated with distinct microbial groups in hierarchical cluster analyses. However, those differences among fungal and bacterial communities diminished during the second year after planting, and soil fungal communities equilibrated faster than bacterial communities. Pre-plant soil treatments altered bulk-soil microbial community composition, but those shifts in soil microbial communities had no obvious correlation with tree performance. Rootstock genotypes were the dominant factor in tree performance after 3 years of observations, and different rootstocks were associated with characteristic bacterial, pseudomonad, fungal, and oomycetes communities in root-zone soil.

scholarly journals Patterns of local, intercontinental and interseasonal variation of soil bacterial and eukaryotic microbial communities

2020 ◽  
Vol 96 (3) ◽  
Author(s):  
Johan De Gruyter ◽  
James T Weedon ◽  
Stéphane Bazot ◽  
Steven Dauwe ◽  
Pere-Roc Fernandez-Garberí ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Microbial Communities ◽  
Community Composition ◽  
Temporal Dynamics ◽  
Soil Microbial Communities ◽  
Soil Microbiome ◽  
Ongoing Research ◽  
Soil Microbial ◽  
Spatio Temporal ◽  
Microbial Groups

ABSTRACT Although ongoing research has revealed some of the main drivers behind global spatial patterns of microbial communities, spatio-temporal dynamics of these communities still remain largely unexplored. Here, we investigate spatio-temporal variability of both bacterial and eukaryotic soil microbial communities at local and intercontinental scales. We compare how temporal variation in community composition scales with spatial variation in community composition, and explore the extent to which bacteria, protists, fungi and metazoa have similar patterns of temporal community dynamics. All soil microbial groups displayed a strong correlation between spatial distance and community dissimilarity, which was related to the ratio of organism to sample size. Temporal changes were variable, ranging from equal to local between-sample variation, to as large as that between communities several thousand kilometers apart. Moreover, significant correlations were found between bacterial and protist communities, as well as between protist and fungal communities, indicating that these microbial groups change in tandem, potentially driven by interactions between them. We conclude that temporal variation can be considerable in soil microbial communities, and that future studies need to consider temporal variation in order to reliably capture all drivers of soil microbiome changes.

scholarly journals An Examination of Soil Microbial Communities and Litter Decomposition in Five Urban Land Uses in Metropolitan Milwaukee, WI, U.S.

2016 ◽  
Vol 42 (1) ◽  
Author(s):  
Keith Turnquist ◽  
Les Werner ◽  
Brian Sloss
Keyword(s):  
Microbial Communities ◽  
Community Composition ◽  
Fungal Community ◽  
C:N Ratio ◽  
Soil Microbial Communities ◽  
Urban Land ◽  
Land Uses ◽  
Fungal Community Composition ◽  
Soil Microbial ◽  
Physical And Chemical

The process of urbanization may alter the ability of microorganisms to supply nutrients to plants. However, both the composition and structure of soil biological communities, and the extent of variation within these communities, is not clear in urban areas. Therefore, baseline information regarding the impact of urban land management practices on soil microbial communities is essential to improving individuals’ ability to manage urban soils and the plants they support. This study examined soil microbial communities over five urban land uses with different degrees of urbanization in metropolitan Milwaukee, Wisconsin, U.S. The objectives were to 1) determine if differences exist in bacterial and fungal community composition, biological activity, and the soil physical and chemical environment across five urban land uses, and 2) determine if differences in the bacterial and fungal compositions compare to differences in the soil’s physical and chemical characteristics. Bulk density, soil organic matter, pH, magnesium, sodium, total nitrogen, and C:N ratio displayed significant differences between streets and forests. Microbial biomass did not differ between land uses, and the differences in bacterial and fungal community composition reflect only a small portion of the total microbial pool. The decomposition of transposed leaf litter showed significant decline in C:N ratio over time, but no statistical differences between land use were observed. The results display a highly redundant microbial assemblage, and suggest that in locations with adequate levels of soil carbon and where parent material and soil forming processes are homogeneous, urbanization and landscape management have less impact on soil microbiology than expected.

scholarly journals Soil Bacterial and Fungal Response to Wildfires in the Canadian Boreal Forest Across a Burn Severity Gradient

2019 ◽  
Author(s):  
Thea Whitman ◽  
Ellen Whitman ◽  
Jamie Woolet ◽  
Mike D Flannigan ◽  
Dan K Thompson ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Microbial Communities ◽  
Community Composition ◽  
Soil Microbial Communities ◽  
Total Carbon ◽  
Burn Severity ◽  
Ecosystem Functions ◽  
Moisture Regime ◽  
Soil Microbial ◽  
Canadian Boreal Forest

Global fire regimes are changing, with increases in wildfire frequency and severity expected for many North American forests over the next 100 years. Fires can result in dramatic changes to C stocks and can restructure plant and microbial communities, which can have long-lasting effects on ecosystem functions. We investigated wildfire effects on soil microbial communities (bacteria and fungi) in an extreme fire season in the northwestern Canadian boreal forest, using field surveys, remote sensing, and high-throughput amplicon sequencing. We found that fire occurrence, along with vegetation community, moisture regime, pH, total carbon, and soil texture are all significant predictors of soil microbial community composition. Communities become increasingly dissimilar with increasingly severe burns, and the burn severity index (an index of the fractional area of consumed organic soils and exposed mineral soils) best predicted total bacterial community composition, while burned/unburned was the best predictor for fungi. Globally abundant taxa were identified as significant positive fire responders, including the bacteria Massilia sp. (64x more abundant with fire) and Arthrobacter sp. (35x), and the fungi Penicillium sp. (22x) and Fusicladium sp. (12x) Bacterial and fungal co-occurrence network modules were characterized by fire responsiveness as well as pH and moisture regime. Building on the efforts of previous studies, our results identify specific fire-responsive microbial taxa and suggest that accounting for burn severity improves our understanding of their response to fires, with potentially important implications for ecosystem functions.

scholarly journals Successive DNA extractions improve characterization of soil microbial communities

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2915 ◽  
Author(s):  
Mauricio R. Dimitrov ◽  
Annelies J. Veraart ◽  
Mattias de Hollander ◽  
Hauke Smidt ◽  
Johannes A. van Veen ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Dna Extraction ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Soil Microbial Communities ◽  
Soil Samples ◽  
Soil Microbial ◽  
Dna Yield ◽  
Microbial Groups

Currently, characterization of soil microbial communities relies heavily on the use of molecular approaches. Independently of the approach used, soil DNA extraction is a crucial step, and success of downstream procedures will depend on how well DNA extraction was performed. Often, studies describing and comparing soil microbial communities are based on a single DNA extraction, which may not lead to a representative recovery of DNA from all organisms present in the soil. The use of successive DNA extractions might improve soil microbial characterization, but the benefit of this approach has only been limitedly studied. To determine whether successive DNA extractions of the same soil sample would lead to different observations in terms of microbial abundance and community composition, we performed three successive extractions, with two widely used commercial kits, on a range of clay and sandy soils. Successive extractions increased DNA yield considerably (1–374%), as well as total bacterial and fungal abundances in most of the soil samples. Analysis of the 16S and 18S ribosomal RNA genes using 454-pyrosequencing, revealed that microbial community composition (taxonomic groups) observed in the successive DNA extractions were similar. However, successive DNA extractions did reveal several additional microbial groups. For some soil samples, shifts in microbial community composition were observed, mainly due to shifts in relative abundance of a number of microbial groups. Our results highlight that performing successive DNA extractions optimize DNA yield, and can lead to a better picture of overall community composition.

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