Download or read book Bacterial Communities Under Soil Disturbance from Experimental Mixing in the Lab to Tillage and Bioturbation in the Field written by Jaimie West and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil microhabitats are heterogeneous, disconnected, and isolated. Thus, soil supports a vast diversity of microbial inhabitants. How do physical disturbances-which disrupt soil microhabitats-affect bacterial community composition and community assembly processes (e.g., selection and dispersal)? Starting in the lab, we evaluated how bacterial communities are affected by soil mixing at various frequencies over a 16-week incubation. We hypothesized that soil mixing would decrease bacterial richness, and that community assembly would be driven by homogenizing dispersal and homogeneous selection. Using 16S rRNA gene sequencing, we found support for our hypotheses, and results further implied that the vast diversity observed in soil is a direct function of the generally unmixed, isolated nature of microbial communities. When we recapitulated this soil mixing experiment under anoxic conditions, findings corroborated the original study: soil mixing homogenized bacterial communities and increased fast growth potential, regardless of oxygen regime. Further, we found that the static anoxic environment decreased bacterial richness overall, and suppressed the influence of mixing-driven selection relative to the oxic treatment. We then took these fundamental ecological findings at the laboratory-scale, and applied them to field settings in southern Wisconsin under real-world soil mixing mechanisms, evaluating long-term tillage in agricultural soils and earthworm bioturbation in forested soils. With these field experiments, we specifically targeted the effects of disturbance on soil aggregation-which protects soil organic matter and promotes soil carbon persistence-and the bacterial communities that inhabit soil microaggregates. The effects of tillage mirrored those of the lab mixing experiments, resulting in more homogeneous soil bacterial communities, driven by homogenizing dispersal. However, bioturbation and aggregate generation due to the casting activity of non-native earthworms (co-occurring Amynthas tokioensis and A. agrestis) did not consistently impose a strong selective filter on the soil bacterial community. Despite high levels of activity in an otherwise relatively undisturbed forest environment, it does not seem that this earthworm activity necessarily acts to homogenize soil communities via dispersal. Further, we did not identify major distinctions between bacterial communities of the free microaggregate vs. occluded-within-macroaggregate microaggregate fractions in either the agricultural tillage study or the forest earthworm bioturbation study, thus suggesting that soil microaggregates readily shift between these operationally defined fractions, particularly at the end of the agricultural growing season, or in the presence of Amynthas spp. earthworms. With this work, we improve our understanding of the microbial response to soil disturbance, and thus the potential implications of increased soil disturbance under global change.

Download or read book Bacterial Community Structure in Soils of the Oldest Agronomic Experiment Fields in the United States the Morrow Plots and of the Original Tallgrass Prairie written by Abiramasundari Ganesan and published by . This book was released on 2019 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diversity of soil microbial communities and their influence on plants growth are widely studied to develop and improve sustainable agricultural practices. Soil-microbe interactions are very complex to interpret given that it involves other biotic and abiotic environmental factors, and the traditional culture-based methods followed by physicochemical analysis are either extremely laborious or not robust enough to investigate the broad picture and intricate details of these complex interactions. The use of molecular technologies like qPCR has resolved some of the shortcomings of culture-based methods, but still exhibited biases in both qualitative and quantitative analyses of microbial communities. New molecular techniques that focus on high throughput DNA sequencing techniques such as 454 pyrosequencing and the MiSeq sequencing platforms revolutionized the field of microbial diversity studies. These techniques are widely used in projects such as the Earth Microbiome Project (EMP), a collective attempt to establish microbial fingerprints in different environments of the planet. Additional applications include studies on long-term effects of crop rotation and different fertilization regimen on bacterial community structure. We tried to build on these studies and assess microbial community structure in the Morrow Plots, the oldest agronomic experimental fields in the United States, and adjacent tallgrass prairie with emphasis on members of the genus Frankia. The Morrow Plots were established in 1876 on tallgrass prairie soils to evaluate the effects of different cropping systems and soil treatments on crop yields, and include the oldest continuous corn plots in the world. Illumina-based l 6S rRNA V3 gene amplicon sequencing retrieved a total of 26.4 7 M effective sequences obtained from 44 samples, i.e. 12 soils with different vegetation and fertilization regimen, and 3 to 6 replicates per soil, with 313,695 to 906,328 reads per sample. At a sequencing depth of 300,000 sequences for each sample, Acidobacteria, Actinobacteria, Proteobacteria and Verrumicrobia were the most abundant bacterial phyla present across all soil samples accounting for 74±4% of the reads. Crop rotation increased diversity of the bacterial community, which was also affected by the fertilization regimen. Reads representing frankiae accounted for 0.1 to 1.0% of all reads, with generally higher percentages in fertilized soils. Reads represented frankiae of clusters la, 2, 3, and 4, but also a group of frankiae that could not reliably be assigned to a cultured relative. The results provide evidence of long-term establishment of Frankia populations in agricultural soils under different management conditions.

Download or read book Understanding Terrestrial Microbial Communities written by Christon J. Hurst and published by Springer. This book was released on 2019-03-27 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a summary of terrestrial microbial processes, which are a key factor in supporting healthy life on our planet. The authors explain how microorganisms maintain the soil ecosystem through recycling carbon and nitrogen and then provide insights into how soil microbiology processes integrate into ecosystem science, helping to achieve successful bioremediation as well as safe and effective operation of landfills, and enabling the design of composting processes that reduce the amount of waste that is placed in landfills. The book also explores the effect of human land use, including restoration on soil microbial communities and the response of wetland microbial communities to anthropogenic pollutants. Lastly it discusses the role of fungi in causing damaging, and often lethal, infectious diseases in plants and animals.

Download or read book Disturbance Ecology of Soil Microbial Communities in Response to the Centralia Pa Coal Fire written by Jackson Winther Sorensen and published by . This book was released on 2019 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial communities are ubiquitous in our world and play important roles in biogeochemical and ecosystems processes on Earth. The ability of these microbial communities to provide these different processes is frequently tied to their community structure, which can be thought of both in terms of membership (i.e. who is there) and the relative abundance of these members. Changes in environmental conditions often lead to changes in microbial community structure as well. Microbial communities are formed through the process of assembly, which in turn is driven by the four processes of 1) Selection 2) Dispersal 3) Drift and 4) Diversification. Understanding the relative importance of each of these processes in different systems is important for predicting how microbial communities will change in response to disturbances. This dissertation presents work that uses the coal fire in Centralia, PA as a model press disturbance for understanding soil microbial community responses to and recovery from disturbance. The experiments herein aim to shed light the relative roles of Selection, Dispersal, and Drift in governing these responses in soil microbial communities experience a temperature disturbance. An observation study of a chronosequence of fire disturbance in Centralia, PA is used to generate hypotheses as to the relative roles of Selection, Dispersal, and Drift in the assembly of soil microbial communities experiencing a temperature disturbance. Further, an in depth look at some of these communities using shotgun metagenomics is used to observe specific microbial traits and characteristics selected for by the temperature disturbance. Finally, a laboratory soil mesocosm warming experiment investigates the relative influence of Dispersal and dormancy in governing responses to and recovery from disturbance.

Download or read book Biocommunication in Soil Microorganisms written by Günther Witzany and published by Springer Science & Business Media. This book was released on 2010-11-01 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: Communication is defined as an interaction between at least two living agents which share a repertoire of signs. These are combined according to syntactic, semantic and context-dependent, pragmatic rules in order to coordinate behavior. This volume deals with the important roles of soil bacteria in parasitic and symbiotic interactions with viruses, plants, animals and fungi. Starting with a general overview of the key levels of communication between bacteria, further reviews examine the various aspects of intracellular as well as intercellular biocommunication between soil microorganisms. This includes the various levels of biocommunication between phages and bacteria, between soil algae and bacteria, and between bacteria, fungi and plants in the rhizosphere, the role of plasmids and transposons, horizontal gene transfer, quorum sensing and quorum quenching, bacterial-host cohabitation, phage-mediated genetic exchange and soil viral ecology.

Download or read book Genetic Diversity of Soil Bacterial Communities written by Carmine Crecchio and published by MDPI. This book was released on 2020-11-13 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book contains research articles and reviews recently published online for the MDPI journal Diversity, in the Special Issue "Genetic diversity of soil bacterial communities". The issue aimed to collect up to date information from the international scientific community to get insight in the "black box", as soil has been defined in the last decades, focusing in detail on the role that the microbial communities have in soil processes such as carbon and nutrient fluxes and on their genetic and functional diversity. The book meets the interests of scientific communities directly involved in the topics investigated, as well as of PhD students, scholars, professional organizations interested in improving their knowledge on a group of organisms considered vitally important to the maintenance and sustainability of the biosphere, where soil has a key role as an important natural resource.

Download or read book Biological Soil Crusts An Organizing Principle in Drylands written by Bettina Weber and published by Springer. This book was released on 2016-05-21 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume summarizes our current understanding of biological soil crusts (biocrusts), which are omnipresent in dryland regions. Since they cover the soil surface, they influence, or even control, all surface exchange processes. Being one of the oldest terrestrial communities, biocrusts comprise a high diversity of cyanobacteria, algae, lichens and bryophytes together with uncounted bacteria, and fungi. The authors show that biocrusts are an integral part of dryland ecosystems, stabilizing soils, influencing plant germination and growth, and playing a key role in carbon, nitrogen and water cycling. Initial attempts have been made to use biocrusts as models in ecological theory. On the other hand, biocrusts are endangered by local disruptions and global change, highlighting the need for enhanced recovery methods. This book offers a comprehensive overview of the fascinating field of biocrust research, making it indispensable not only for scientists in this area, but also for land managers, policy makers, and anyone interested in the environment.

Download or read book Links Between Soil Microbial Communities and Transformations of Soil Carbon and Nitrogen Along a Gradient in Land use History and Soil Disturbance written by Kerri Loraine Steenwerth and published by . This book was released on 2003 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unravelling the Soil Microbiome written by Rama Kant Dubey and published by Springer. This book was released on 2019-05-24 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the significance of soil microbial diversity to understand its utility in soil functions, ecosystem services, environmental sustainability, and achieving the sustainable development goals. With a focus on agriculture and environment, the book highlights the importance of the microbial world by providing state-of-the-art technologies for examining the structural and functional attributes of soil microbial diversity for applications in healthcare, industrial biotechnology, and bioremediation studies. In seven chapters, the book will act as a primer for students, environmental biotechnologists, microbial ecologists, plant scientists, and agricultural microbiologists. Chapter 1 introduces readers to the soil microbiome, and chapter 2 discusses the below ground microbial world. Chapter 3 addresses various methods for exploring microbial diversity, chapter 4 discusses the genomics methods, chapter 5 provides the metaproteomics and metatranscriptomics approaches and chapter 6 details the bioinformatics tools for soil microbial community analysis, and chapter 7 concludes the text with future perspectives on further soil microbial uses and applications.

Download or read book Genetic Characterization of Soil Bacterial Communities in the DOK Long term Agricultural Field Experiment written by Martin Hartmann and published by . This book was released on 2006 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experiments in Soil Bacteriology written by Oscar Nelson Allen and published by . This book was released on 1959 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Laboratory Manual of Soil Bacteriology written by Edwin Broun Fred and published by . This book was released on 1916 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recovery of Soil Microbial Communities After Disturbance written by Sadikshya Rana Dangi and published by ProQuest. This book was released on 2008 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil microbial communities were examined in two chronosequences of reclaimed surface mine soil and in a chronosequence of previously burned sites to determine how these communities recover through time after disturbance. Phospholipid fatty acid (PLFA) methods for microbial community analysis were used to quantify microbial biomass, diversity, and abundance of specific microbial groups (gram positive bacteria, gram negative bacteria, fungi, arbuscular mycorrhizal fungi, and actinomycetes). Multivariate analysis of variance (MANOVA) and discriminant analysis (DA) were used to compare soil microbial communities and site environmental factors. The soil microbial community in sagebrush-grassland ecosystems disturbed by fire appeared to recover to similar levels of biomass and diversity as in unburned soil within 3 to 7 years. In the surface mine reclamation sites, microbial recovery was seen in 5 to 10 years after reclamation in sites dominated by sagebrush and within 14 years after reclamation in the sites dominated by cool season grasses. Plant community composition was found to have influences in soil microbial recovery. Microbial communities in soil under crested wheatgrass (Agropyron cristatum) recovered to greater biomass than did the communities associated with other plant species. Soil fungi appeared to be the most adversely affected by soil disturbance associated with surface mining than the other microbial groups examined, and they were also slow to recover after the initiation of reclamation. A general trend of recovery towards the undisturbed condition with reclamation age was found for all microbial groups after disturbance. Our data on microbial community recovery from fire and impacts of surface mining suggests that soil microbial communities are highly resilient to disturbances.

Download or read book Exploring Bacterial Communities and Their Function for Soil Health Under Different Cropping Systems written by Ru Li and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rhizosphere and soil bacteria are important drivers in nearly all biochemical cycles in terrestrial ecosystems and participate in maintaining health and productivity of soil in agriculturally managed systems. However, the effect of agricultural management systems on bacterial communities is still poorly understood. In this study, cultural methods and advanced molecular methods (terminal restriction fragment length polymorphism (TRFLP) and 454- pyrosequencing) were used to identify shifts in soil and rhizosphere bacterial diversity, community composition, and functions under different cropping systems in Manitoba, Canada. This included monoculture vs. rotation, zero tillage vs. conventional tillage, and organic farming vs. conventional farming. Results showed that: (1) different cropping systems did not significantly influence the diversity of bacterial communities. However, a significant variation in relative abundances of bacterial communities at both the phylum and genus level was observed among different cropping systems. Compared to conventional farming systems, organic farming system had a higher percentage of the phylum Proteobacteria (many Plant Growth Promoting Rhizosbacteria) and a lower percentage of the phylum Actinobacteria. When canola monoculture was compared to wheat-oat-canola-pea rotation, a significantly higher percentage of Proteobacteria and a lower percentage of Actinobacteria were found in the rotational system. Wheat monoculture shared similar bacterial communities with wheat-oat-canola-pea rotation. Zero tillage did not change bacterial community profiles except for an increase in Firmicutes (many PGPR), compared to conventional tillage. At the genus level, significant differences were found for the dominant genera Pseudomonas, Rhizobium, Stenotrophomonas, Brevundimonas, Burkholderia, Marmoricola, Microlunatus, and Solirubrobacter. The bacterial distribution was strongly associated with soil pH. (2) The cropping systems also influenced the antibiotic-producing Pseudomonas populations determined through PCR-based screening for the detection of genes involved in the biosynthesis of antibiotics. It was found that pyrrolnitrin- and phenazine- producing Pseudomonas spp. were more prevalent in the soil under zero tillage and organic farming systems, while 2,4-DAPG and pyoluteorin-producing strains were not found in this study. This comprehensive study provided fundamental information on how different cropping systems affect soil and rhizosphere bacterial communities, which can be used to guide Manitoba farmers to choose proper farming systems to maintain soil health and increase PGPR populations in soil.

Download or read book Biological Soil Crusts Spatio temporal Development and Ecological Functions of Soil Surface Microbial Communities across Different Scales written by Shubin Lan and published by Frontiers Media SA. This book was released on 2024-08-09 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological soil crusts (biocrusts) are widely distributed throughout the world, and cover approximately 12% of the terrestrial surface. Biocrusts are composed of cyanobacteria, algae, lichens, mosses, and a great diversity of other microorganisms, which bind soil particles together to form a layer of biological-soil matrix on the soil surface typically of several millimetres thickness. They are important sites of regional and global microbial diversity and perform multiple ecological functions (multifunctionality). During the evolution of terrestrial life on earth, biocrusts are regarded as the main colonising photosynthetic organisms before the advent of vascular vegetation. They not only represent the early stages of terrestrial ecosystems, but also facilitate the ecosystem’s development and succession. Therefore, biocrusts are recognised as ecological engineers in the natural development of ecosystems and for the restoration of degraded terrestrial ecosystems. The development of biocrusts is highly heterogeneous, which is reflected on both temporal and spatial scales, and this heterogeneity is still clearly visible even in a small scale. However, up to now, only limited knowledge is acquired on biocrust temporal and spatial organisation. In particular there still is a large knowledge gap regarding the various biocrust communities under different developmental states and their related physiological metabolisms and ecological functions. Therefore, in-depth studies of these issues will undoubtedly further promote our understanding of the heterogeneous development of biocrusts, as well as their ecological multifunctionality in terrestrial ecosystems. The relevant contributions are expected to provide a scientific basis for the management of biocrusts and technology development (e.g. cyanobacteria-induced biocrust technology) for ecological restoration and the promotion of soil health.

Download or read book Effects of Nutrient Availability and Disturbance on the Composition and Diversity of Soil Microorganisms written by Joshua C. Thigpen and published by . This book was released on 2015 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Determining how factors such as disturbance and nutrient availability affect species diversity in a community has been a major goal of community ecology. The purpose of this study was to look at how species diversity and composition of soil bacterial communities are affected by nutrient addition and disturbance. I characterized soil microbial communities at the long-term ecological research site at the West Research Campus (WRC) located in Pitt County, NC. Briefly, DNA extracted from soils was analyzed using amplicon sequencing of the 16S ribosomal RNA gene. The Illumina Platform was used to sequence the bacterial DNA from each sample, and the Mothur Pipeline was used to analyze the DNA sequences. I hypothesized that changes in nutrient availability and disturbance would impact soil microbial community composition and diversity through direct and indirect effects mediated by plant-soil interactions. My research complemented previous work carried out in the WRC determining the effects of nutrient addition and disturbance on plant communities. Analysis of 2013 plant data showed that mowing increased plant species richness, and fertilization decreased plant species richness significantly. The experimental treatments as well as the proximity of the blocks to a drainage ditch all had significant effects on plant community composition. Analysis of the microbial community data showed that both fertilization and mowing significantly increased mean species richness. Relative abundance microbial community composition varied significantly due to the proximity of the blocks to the ditch. Presence/absence microbial community analyses showed significant effects of the treatments, as well as ditch proximity on microbial composition differences. Also, unknown microbial communities showed significant variation of the communities due to the treatments. The results of the presence/absence analysis and the unknown microbial community analysis show the importance of rare taxa and unknown microbial communities to the differences in composition of our soil microbial communities. Analysis of the soil chemical and physical data showed very little variation due to the treatments. This study will contribute to our understanding of how both plant and soil bacterial community diversity are affected by anthropogenic nutrient addition and disturbances. Maintaining diversity is important for ecosystem stability and functioning.

Download or read book Modern Soil Microbiology Second Edition written by Jan Dirk van Elsas and published by CRC Press. This book was released on 2006-12-21 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the ten years since the publication of Modern Soil Microbiology, the study of soil microbiology has significantly changed, both in the understanding of the diversity and function of soil microbial communities and in research methods. Ideal for students in a variety of disciplines, this second edition provides a cutting-edge examination of a fascinating discipline that encompasses ecology, physiology, genetics, molecular biology, and biotechnology, and makes use of biochemical and biophysical approaches. The chapters cover topics ranging from the fundamental to the applied and describe the use of advanced methods that have provided a great thrust to the discipline of soil microbiology. Using the latest molecular analyses, they integrate principles of soil microbiology with novel insights into the physiology of soil microorganisms. The authors discuss the soil and rhizosphere as habitats for microorganisms, then go on to describe the different microbial groups, their adaptive responses, and their respective processes in interactive and functional terms. The book highlights a range of applied aspects of soil microbiology, including the nature of disease-suppressive soils, the use of biological control agents, biopesticides and bioremediation agents, and the need for correct statistics and experimentation in the analyses of the data obtained from soil systems.