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Jeffery, Simon. „The microbiology of arable soil surfaces“. Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/2245.
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Whilst much is known about the physics and erosion of soil surfaces on a millimetre scale, little is known about the associated microbiology, particularly in temperate arable systems. The vast majority of research regarding microbial interactions at soil surfaces has concerned microbiotic crusts. However, such surface crusts take many years to form and then only in relatively undisturbed soil systems. Arable soil surfaces are subject to relatively extreme environmental conditions, potentially undergoing rapid changes in relation to temperature, water status and solar radiation compared to deeper soil zones. These extreme environmental parameters are likely to have a large impact on the biota found at the arable soil surface when compared to that which occurs in deeper soil zones. Phenotypic profiling using phospholipid fatty acid (PLFA) analysis, microbial biomass, and chlorophyll concentration were used to characterise soil microbial communities with the aim of quantifying differences within the surface layers of arable systems on a millimetre scale. This field work was supported with a series of microcosm-scale studies in which parameters such as length of time between disturbance events and the quality of light reaching the soil surface were controlled. Using microcosms subjected to simulated rainfall and imaged using X-ray computed tomography scanning, the effects of the soil surface microbiota on associated physical properties including structural integrity, porosity, erodibility and hydrological properties were investigated. This research showed that given sufficient time between disturbance events, environmental parameters such as temperature and wet:dry cycling were sufficient to drive the formation of a distinct soil surface phenotype, which appeared to be consistently confined to an order of depth of circa 1 mm. It was notable that the PLFA 16:0 was consistently associated with discrimination between phenotypes between soil surface layers. Calculation of the ratio of fungal to bacterial PLFA biomarkers showed a consistently higher ratio of fungi to bacteria present in the soil surface layer to a depth of circa 1 mm, providing evidence that fungi grow preferentially over the soil surface compared to through the soil matrix. Further investigation demonstrated that light, particularly at photosynthetically active wavelengths, was the main driving factor in the establishment of the distinct soil surface phenotypes. The inocula which drove the formation of such soil-surface community phenotypes, especially the photoautotrophic components, was demonstrated to derive predominantly from aerial sources. Functionally the nature of the soil surface community was found to affect run-off generation and shear strength at the surface. There was no significant impact of the soil surface microbiota on erodibility or water infiltration rates, although whilst distinct surface phenotypes had developed in this experimental circumstance, these were relatively deficient in photoautotrophs compared to other microcosm experiments and field circumstances, and hence extrapolation of this conclusion is not sound. This project has demonstrated that a soil surface ecological niche may exist in other unexplored soil surfaces and highlights the needs to explore this possibility and to examine any associated functional consequence should such niches be found to exist.
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Jones, Frances Patricia. „The microbiology of lean and obese soil“. Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/69408/.
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The bacterial genus Bradyrhizobium is biologically important within soils, with different representatives found to perform a range of functions including nitrogen fixation through symbioses, photosynthesis and denitrification. The Highfield experiment at Rothamsted provides an opportunity to study the impact of plants on microbial communities as it has three long-term contrasting regimes; permanent grassland, arable and bare fallow (devoid of plants). The bare fallow plots have a significant reduction in soil carbon and microbial biomass. Bradyrhizobium has been shown by metagenomic studies on soil to be one of the most abundant and active groups including in bare fallow soil indicating that some phenotypes are adapted to survive in the absence of plants. A culture collection was created with isolates obtained from contrasting soil types from Highfield in addition to woodland soil, gorse (Ulex europeaus) and broom (Cytisus scoparius) root nodules. The collection’s phylogeny has been explored by sequencing housekeeping genes to determine whether soil treatment affects the core genome. One grassland and one bare fallow isolate had their genome sequenced and differences have been assessed to establish their potential for a range of functions and to direct future experiments. The functional diversity of the collection has been investigated using carbon metabolism assays to identify key substrates and determine whether the isolates group according to soil treatment. Symbiosis capacity and role in nitrogen cycling has been examined using nodulation tests, anaerobic growth on nitrate and nitrous oxide production and reduction through denitrification. A high level of diversity can be seen throughout the collection with differences being linked to niche adaptation. Understanding more about Bradyrhizobium could give clues on how above ground management impacts a key group within the soil community. Furthermore, the first assembled genomes of two non-symbiotic Bradyrhizobium strains isolated from soil provide an important resource for microbiology and soil ecology.
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Paulse, Arnelia N. (Arnelia Natalie). „Soil stabilization by microbial activity“. Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53593.
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Thesis (MSc)--Stellenbosch University, 2003.ENGLISH ABSTRACT: Microorganisms play an important role in the stability and maintenance of the ecosystem and in the condition of the soil. However, in their natural environment, microorganisms often experience changing and hostile conditions. They therefore need to be able to adapt physiologically and modify their micro-environment. Biofilm formation is one mechanism to establish favorable micro-environments. The extracellular polymeric substances (EPS) that are typically associated with biofilm formation may also have an impact on soil structure. The aim of this project was to evaluate the potential of microbial manipulation on EPS production and the possible impact thereof on soil structure in order to improve water retention. Specific objectives of this study included the screening of natural environments for EPS-producers, developing techniques to observe EPS production and accumulation in the pores between soil particles, measuring the effect of EPS production on soil water hydraulic gradient, as well as determining the fate and impact of EPS-producers when introduced to naturally-occurring soil microbial communities. Several environmental samples have been screened for EPS-producing microorganisms. Soil columns were then inoculated with these EPS-producers and the passage of 20 mlaliquots water through the columns measured at 3 or 4-day intervals. Microbes isolated from soil, through their EPS production capability proved to retain water more effectively than was the case for water-borne EPS-forming microbes. This phenomenon was further studied using flow cells, filled with soil and inoculated with the EPS-producers isolated from either soil or water. Fluorescence microscopy showed that the soil microbes produced EPS that clogged pores between sand particles more effectively. This clogging resulted in lowering the soil water hydraulic gradient. To evaluate the effect of EPS-producers on existing soil microbial communities, cell counts, Biolog™whole-community carbon utilization studies and T-RFLP (terminal-restriction fragment length polymorphism) analyses were performed. Shifts in the soil microbial community could not be readily seen by observing microbial numbers and T-RFLP-analysis, but was noticeable in carbon utilization patterns.
AFRIKAANSE OPSOMMING: Mikroorganismes speel 'n belangrike rol in die stabiliteit en instandhouding van die ekosisteem en in die kondisie van die grond. In hul natuurlike omgewing ervaar mikroorganismes dikwels veranderlike en ongunstige toestande. Mikroorganismes het dus nodig om hulself fisiologies aan te pas en verander hul mikro-omgewing daarvolgens. Biofilm-vorming is een meganisme om gunstige mikro-omgewings te skep. Die ekstrasellulêre polimeriese produkte (EPP) wat tydens biofilm-vorming gevorm word, mag ook 'n impak hê op die grondstruktuur. Die doel van hierdie projek was om die potensiaal van mikrobiese manipulasie op EPP-vorming te evalueer asook die moontlike impak daarvan op grondstruktuur wat sodoende waterretensie kon bevorder. Die spesifieke doelwitte van hierdie studie het ingesluit die isolasie van EPPproduseerders vanuit natuurlike omgewings, die ontwikkeling van verskeie tegnieke waarvolgens EPP-produksie en die akkumulasie daarvan in die porieë tussen gronddeeltjies bestudeer kon word, die effek van EPP-produksie op hidrouliese gradiënt van grondwater en om die lot en impak wat EPP-produseerders op natuurlike grondmikrobiese populasies te bepaal. Verskeie grond- en watermonsters was getoets vir die voorkoms van EPP-produserende mikroorganismes. Grondkolomme is geïnokuleer met EPP-produseerders en die vloei van 20 ml-volumes water deur die kolomme is gemeet met 3 of 4-dag intervalle. Grond-geïsoleerde mikrobes het beter waterretensie tot gevolg gehad as water- geïsoleerde mikrobes. Hierdie verskynsel was verder bestudeer deur die gebruik van vloeiselle, gevul met grond of sand en geïnokuleer met EPP-produseerders geïsoleer vanuit grond of water. Fluoressensie mikroskopie het aangetoon dat grondmikrobes EPP produseer wat die porieë tussen gronddeeltjies meer effektief verstop. Dié verstopping het gelei tot die verlaging van die grondwater se hidrouliese gradiënt wat bepaal is deur die gebruik van die konstante-vlak bepalingsmetode. Om die effek van EPP-produseerders op bestaande mikrobiese populasies te bepaal, is seltellings, Biolog™ heel-gemeenskap koolstofverbruik studies en T-RFLP (terminale-restriksie fragment-lengte polimorfisme) analises uitgevoer. Veranderinge in die mikrobiese populasie kon nie geredelik bloot deur die bepaling van mikrobiese getalle en T-RFLP-analise waargeneem word nie, maar wel met die koolstofverbruikspatrone.
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Wagai, Rota. „Climatic and Lithogenic Controls on Soil Organic Matter-Mineral Associations“. Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/WagaiR2005.pdf.
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Marí, Marí Teresa. „Changes in soil biodiversity and activity along management and climatic gradients“. Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/457976.
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Els anomenats “rangelands” són àrees sense cultivar, àmpliament pasturades per animals domèstics i salvatges, actualment amenaçats pels canvis climàtic i en l’ús del sòl. Els microorganismes del sòl tenen un paper clau tant en la descomposició com en diversos processos de l’ecosistema, fet pel qual composició i funció de la comunitat microbiana han estat utilitzats durant molt temps com a índexs de fertilitat del sòl.
Els rangelands europeus i africans comparteixen un origen antropogènic comú, però el clima i la gestió del sòl els afecten d’una manera diferent. És per això que aquesta tesi pretén analitzar la comunitat microbiana d’ambdós tipus d’ecosistemes, per tal d’observar els efectes d’algunes de les amenaces comunes des d’una perspectiva més global.
Mentre que la sobrepastura va demostrar tenir l’efecte més perjudicial sobre la funció microbiana en sòls kenyans, es va trobar un efecte més fort del clima sobre els prats europeus. Els fongs i els bacteris van covariar al llarg de gradients altitudinals i climàtics, però la comunitat bacteriana va mostrar una recuperació més ràpida després de les pertorbacions biològiques i físico-químiques del sòl.
Aquest conjunt d’estudis afegeix nous coneixements sobre l’estructura i funció dels rangelands africans i europeus, i convida a explorar noves línies de recerca que incloguin tant bacteris com fongs alhora d’estudiar la comunitat microbiana del sòl.Los llamados "rangelands" son áreas sin cultivar, ampliamente pastoreadas por animales domésticos y salvajes, actualmente amenazados por los cambios climático y de uso del suelo. Los microorganismos del suelo tienen un papel clave tanto en la descomposición como en diversos procesos del ecosistema, por lo que composición y función de la comunidad microbiana han sido utilizados durante mucho tiempo como índices de fertilidad del suelo. Los rangelands europeos y africanos comparten un origen antropogénico común, pero el clima y la gestión del suelo les afectan de una manera diferente. Es por ello que esta tesis pretende analizar la comunidad microbiana de ambos tipos de ecosistemas, a fin de observar los efectos de algunas de las amenazas comunes desde una perspectiva más global. Mientras que el sobrepastoreo demostró tener el efecto más perjudicial sobre la función microbiana en suelos kenianos, se encontró un efecto más fuerte del clima sobre los prados europeos. Los hongos y las bacterias covariaron a lo largo de gradientes altitudinales y climáticos, pero la comunidad bacteriana mostró una recuperación más rápida después de las perturbaciones biológicas y físico-químicas del suelo. Este conjunto de estudios añade nuevos conocimientos sobre la estructura y función de los rangelands africanos y europeos, e invita a explorar nuevas líneas de investigación que incluyan tanto bacterias como hongos en el estudio de la comunidad microbiana del suelo.
Rangelands are uncultivated areas extensively grazed by wild and domestic animals, currently threatened by land use and climatic changes. Soil microorganisms play a key role in decomposition and several ecosystem processes and the composition and function of the microbial community have been long used as indices of soil fertility. African and European rangelands share a common anthropogenic origin, but climate and management affect them in a different way. That is why this thesis aimed to analyze the microbial community of both in order to observe the effects of some common threats from a more global perspective. While overgrazing proved to have the most detrimental effect on the soil microbial function in Kenyan soils, a stronger effect of climate was found to affect European grasslands. Fungi and bacteria co-varied along altitudinal and climatic gradients, but the bacterial community showed a fast recovery after biological and soil physico-chemical disturbances. This group of studies adds new knowledge on the structure and function of the African and European rangelands, and invite to explore new lines of research including both fungal and bacterial consortia when studying the soil microbial community.
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Rodriguez, Luis A. (Luis Antonio). „Adenylate Energy Charge Determinations of Soil Bacteria Grown in Soil Extract Medium“. Thesis, University of North Texas, 1988. https://digital.library.unt.edu/ark:/67531/metadc500662/.
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The adenylate energy charge values of twenty bacteria isolated from soil and cultured in a medium consisting of soil and distilled water were determined by the luciferin-luciferase bioluminescense method. The purpose of this study was to examine the growth and energy charge values of these organisms in soil extract medium, and to determine what effect the addition of glucose has on their energy charge values. Three of the organisms employed in this study showed energy charge values similar to those reported for bacteria grown in enriched media. The remainder of the isolates demonstrated low energy charge values, and scant growth in the soil medium.
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Bester, Reinhard. „Growth and survival of Saccharomyces cerevisiae in soil“. Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/16597.
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Thesis (MSc)--University of Stellenbosch, 2005.ENGLISH ABSTRACT: Saccharomyces cerevisiae is commonly associated with the wine industry. However, this yeast was also isolated from soils not associated with vines. Despite the fact that S. cerevisiae is not perceived as an autochthonous soil yeast, its interaction with other soil microbiota suggests the contrary. Aside from a few in vitro studies, the fate of S. cerevisiae in soil is largely unknown. This may partly be ascribed to the lack of reliable methods to enumerate fermentative yeasts in soil. Consequently, we evaluated an enumeration procedure for fermentative yeasts in soil, whereby yeast malt extract (YM) agar plates containing selective agents, were incubated in anaerobic jars before the colonies were enumerated. This procedure proved to be selective for fermentative yeasts, such as industrial strains of S. cerevisiae. We then commenced studying the growth and survival of S. cerevisiae in soil differing in moisture content and nutrient levels, using S. cerevisiae strain S92 and the genetically modified strain S. cerevisiae ML01, as well as two autochthonous soil yeasts, Cryptococcus laurentii and Cryptococcus podzolicus. The yeast strains were each inoculated into three series of microcosms containing sterile soil with a moisture content of ca. 30% (v/w), a moisture content of ca. 15% (v/w), or a moisture content of ca. 30% supplemented with nutrients used in agriculture. Growth of each strain was monitored for a period of 48 days and all the yeasts were found to grow or survive under these conditions, up until the end of the incubation period. Generally, the cryptococci reached larger population sizes in the soil than the Saccharomyces strains, which may be due to their ability to utilize a wider range of carbon sources and to survive in semi-arid soils. Aside from cell numbers observed in nutrient supplemented soil, in which S. cerevisiae ML01 reached higher numbers than S92, there was no significant difference between the growth and survival of the Saccharomyces strains. In all the microcosms, metabolic rates, as determined by measuring CO2 emissions from soil, reached a maximum within the first day and then declined over the remainder of the trial, possibly due to depletion of nutrients. Differences in CO2 emissions from the different series of microcosms were attributed to different metabolic rates and energy expenditure needed to maintain yeast populations under different conditions. Each of the above-mentioned yeasts was subsequently inoculated in a microcosm prepared from non-sterile soil and monitored using selective enumeration procedures. The Saccharomyces strains were enumerated using the above-mentioned soil dilution plates incubated in anaerobic jars. The presence of natural soil biota caused a decrease in viable yeast numbers for all strains and this was ascribed to competition with and predation by other soil borne organisms. Further evidence for competition and/or amensalism impacting on Saccharomyces populations in soil was obtained when monitoring co-cultures of Saccharomyces with C. laurentii 1f and C. podzolicus 3f in soil microcosms, revealed a significant reduction in Saccharomyces numbers during a 28 day incubation period. However, when the two Saccharomyces strains were cultured in soil microcosms inoculated with a protistan predator, populations of both strains increased and remained at these high levels for the duration of the trial. These findings point to a possible symbiosis between Saccharomyces and the protista whereby the predators ensure continuous nutrient cycling within the soil microcosms. In the final part of the study, epifluorescence microscopy revealed that, similar to known soil cryptococci, the two Saccharomyces strains were able to form biofilms in oligotrophic conditions. The results of this study showed that in the presence of natural soil microbes, no differences exist between the growth and survival of S. cerevisiae S92 and S. cerevisiae ML01. Also, the findings point to a natural niche for this species somewhere in the soil habitat.
AFRIKAANSE OPSOMMING: Saccharomyces cerevisiae word algemeen met die wynindustrie geassosieer. Hierdie gis is egter ook uit grond geïsoleer wat nie met wingerd geassosieer word nie. Ten spyte van die feit dat S. cerevisiae nie as ‘n outogtoniese grondgis beskou word nie, dui sy interaksie met ander grondmikrobiota op die teendeel. Behalwe vir ‘n paar in vitro studies, is die lot van S. cerevisiae in grond grootliks onbekend. Dit mag gedeeltelik aan die gebrek aan betroubare metodes om fermenterende giste in grond te tel, toegeskryf word. Ons het gevolglik ‘n tellingsmetode vir fermenterende giste in grond geëvalueer waarin gis-mout ekstrak (GM) agar plate, bevattende selektiewe agente, in anaërobiese flesse geïnkubeer is voordat die kolonies getel is. Hierdie metode was selektief vir fermenterende giste, soos die industriële stamme van S. cerevisiae. Hierna is die groei en oorlewing van S. cerevisiae bestudeer in gronde met verskillende vog- en nutriëntvlakke deur gebruik te maak van S. cerevisiae stam S92 en die geneties gemodifiseerde stam S. cerevisiae ML01, asook twee outogtoniese grondgiste, Cryptococcus laurentii en Cryptococcus podzolicus. Die gisstamme is elk geïnokuleer in drie reekse van mikrokosmosse bestaande uit steriele grond met ‘n vogvlak van ca. 30% (v/w), ‘n vogvlak van ca. 15% (v/w), of ‘n vogvlak van ca. 30% aangevul met landbounutriënte. Die groei van elke stam is waargeneem vir ‘n tydperk van 48 dae en al die giste het onder hierdie omstandighede tot aan die einde van die inkubasietydperk gegroei of oorleef. Oor die algemeen het die cryptococci groter populasies in die grond gevorm as die Saccharomyces stamme, wat toegereken kan word aan hul vermoë om ‘n wyer reeks koolstofbronne te benut en om in droë gronde te oorleef. Behalwe dat S. cerevisiae ML01 ‘n hoër aantal selle in nutriënt aangevulde grond behaal het as S92, was daar geen beduidende verskil tussen die groei en oorlewing van die Saccharomyces stamme nie. In al hierdie mikrokosmosse het die metaboliese tempo, soos bepaal deur CO2 vrystellings vanuit grond te meet, ‘n maksimum bereik binne die eerste dag en dan het dit afgeneem oor die res van die toetsperiode, waarskynlik as gevolg van die uitputting van die nutriënte. Verskille in die CO2 vrystellings wat vir die verskillende reekse van mikrokosmosse aangeteken is, is te wyte aan die verskillende metaboliese tempo’s en energiegebruik benodig om gispopulasies onder verskillende omstandighede in stand te hou. Elk van bogenoemde giste is vervolgens geïnokuleer in ‘n mikrokosmos wat voorberei is van nie-steriele grond, en waargeneem deur selektiewe enumerasie prosedures toe te pas. Die Saccharomyces stamme is getel deur gebruik te maak van bogenoemde grondverdunningsplate wat in anaërobiese flesse geïnkubeer is. Die teenwoordigheid van natuurlike grondbiota het in alle stamme ‘n afname in lewensvatbare gisgetalle veroorsaak en is toegeskryf aan die kompetisie met en predasie deur ander grondorganismes. Verdere bewys van die impak van kompetisie en/of amensalisme op Saccharomyces populasies in die grond, is die beduidende afname in Saccharomyces getalle tydens ‘n 28 dag inkubasie tydperk, waartydens ko-kulture van Saccharomyces stamme met C. laurentii 1f en C. podzolicus 3f in grond mikrokosmosse ondersoek is. Toe die twee Saccharomyces stamme egter in grond mikrokosmosse opgekweek is wat met ‘n protistiese predator geïnokuleer is, het populasies van albei stamme gegroei en om hierdie hoë vlakke gebly tot aan die einde van die toets. Hierdie bevindings dui ‘n moontlike simbiose tussen Saccharomyces en die protista aan waardeur die predatore deurlopende nutriëntsiklering binne die grondmikrokosmos verseker. In die laaste deel van die studie toon epifluoressensie mikroskopie aan dat, net soos bekende grond cryptococci, die twee Saccharomyces stamme in staat is om biofilms in oligotrofiese omstandighede te vorm. Die resultaat van die studie toon aan dat in die teenwoordigheid van natuurlike grondmikrobe daar geen verskil tussen die groei en oorlewing van S. cerevisiae S92 en S. cerevisiae ML01 is nie. Die bevindings dui ook aan dat daar ‘n natuurlike nis vir hierdie spesie iewers in die grondhabitat is.
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Coyle, Kieran. „An investigation of the role of soil micro-organisms in phosphorus mobilisation : a report submitted to fulfil the requrements of the degree of Doctor of Philosophy“. Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phc8814.pdf.
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Hoyle, Frances Carmen. „The effect of soluble organic carbon substrates, and environmental modulators on soil microbial function and diversity /“. Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0050.
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Jenkins, Anthony Blaine. „Organic carbon and fertility of forest soils on the Allegheny Plateau of West Virginia“. Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2486.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains x, 282 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
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Menefee, Dorothy. „Anthropogenic influences on soil microbial properties“. Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32657.
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Master of ScienceDepartment of Agronomy
Ganga M. Hettiarachchi
Human activities have the potential to alter soil biochemical properties in a number of different ways. This thesis will focus on how agricultural practices (tillage and cropping system), climate change, and urban soil pollution (primarily lead and arsenic) affect soil biochemical properties. Two incubation studies were conducted to determine how human activities influence soil biochemical properties. The first study focused on how altered temperature and moisture regimes affected soil properties from four different agroecosystems. Four different soils were incubated under two different soil preparation methods (sieved <4mm and <0.25 mm), three different temperature treatments (12, 24, and 36°C), and two different moisture treatments (field capacity and 80% of field capacity) for 180 days. Destructive samples were taken at 7, 30, 60, 120, and 180 days and the soil microbial community was analyzed using phospholipid fatty acid analysis (PLFA). The second study investigated how soil amendment treatments (Mushroom Compost and Composted Biosolids) of an industrially contaminated site affected the biochemical properties of that soil. Surface soil samples collected 435 days after compost addition from urban garden test plots located adjacent to a former rail yard in Monon, Indiana. Soils were incubated for 30 days to stimulate microbial activity. Following incubation, the soil was analyzed for PLFA, soil enzymes, and available metal fractions. In the first study the greatest differences were found between the <4mm and the <0.25 mm size fractions – which highlights the effect of soil aggregation and structure on microbial populations. After aggregation effects, temperature treatment had the next largest effect on microbial populations, with the greatest biomass in the middle (24°C) treatment. The second study assessed different soil amendments on soil microbial properties and metal availability. Composted biosolids reduced metal availability and increased microbial enzyme activity and biomass.
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Sutanto, Yovita. „Manure from grazing cattle effects on soil microbial communities and soil quality in northern West Virginia pastures /“. Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3933.
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Thesis (M.S.)--West Virginia University, 2005.Title from document title page. Document formatted into pages; contains vii, 72 p. : ill. (some col.), map. Includes abstract. Includes bibliographical references.
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Sheremata, Tamara W. „The influence of soil organic matter on the fate of trichloroethylene in soil“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0017/NQ44582.pdf.
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Blair, Jennifer M. „Mechanistic modelling of bioavailability : putting soil microbiology in its pore scale context“. Thesis, Abertay University, 2007. https://rke.abertay.ac.uk/en/studentTheses/bf7beb4b-07fa-41a8-8eeb-25aabf2669a7.
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The soil-microbe complex was investigated in terms of the relationship between the physical soil structure and related functional characteristics. The use of CT scanning technology provided a means of obtaining high-resolution digital reconstructions of the internal soil structures in three dimensions thus allowing, for the first time, the internal architecture of soil to be investigated. The investigation of soil structure was facilitated through the development of a theoretical modelling framework that acted as a virtual laboratory. A suite of metrics was implemented within the modelling framework to allow the quantification of the physical soil structure. The analysis of a range of CT imaged soil structures via the quantification metrics showed that the micro-structure of soil can span a range of porosities and textures. The metric values obtained for individual structures characterise the features of the structures that play an influential role in mediating the functional value of a sample. A model that simulates soil structure in three dimensions from two-dimensional data is shown to reproduce the key structural characteristics of soil at the micro-scale. Data extracted from the CT imaged soil samples were extracted to parameterise the model and thus the simulated soil structures were validated against the original CT imaged structure using the quantification metrics. In general, the model adequately reconstructed the variation found across the CT imaged samples. However, for low porosity samples the complex pore architectures were not captured. The soil structures were used to simulated oxygen transport through the microenvironment to microbial active sites thus allowing the examination of the impact of physical structure on microbial respiration. The results presented show that soil structure is the determining factor in bulk respiration of the soil microenvironment.
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Watts, Dexter Brown. „Mineralization in soils amended with manure as affected by environmental conditions“. Auburn, Ala. :, 2007. http://repo.lib.auburn.edu/2007%20Spring%20Dissertations/WATTS_DEXTER_20.pdf.
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Williams, David. „Ecophysiological studies of soil ammonia oxidising bacteria“. Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26464.
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Jones, Hilary A. „The oxidation of methane in landfill soil cover“. Thesis, University of Essex, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306045.
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18
Trubl, Gareth. „Pioneering Soil Viromics to Elucidate Viral Impacts on Soil Ecosystem Services“. The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543425468999981.
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Herron, Paul Robert. „Interactions between actinophage and streptomycetes in soil“. Thesis, University of Warwick, 1991. http://wrap.warwick.ac.uk/79686/.
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A method was developed based upon soil dispersion using an ion exchange resin and differential centrifugation that allowed the selective isolation of Streptomyces spores rather than mycelia; this allowed the characterisation of a germination/sporulation cycle in situ. The method was able to detect relatively low numbers of streptomycetes in soil, through its concentrating action. The ecology of a temperate actinophage derived from 4'C31, containing the thiostrepton-resistance gene, was studied in conjunction with strains of Streptomyces lividans. In sterile amended soil, phage numbers showed initial increases due to a corresponding germination of the host spore inoculum; subsequently phage numbers declined when the host streptomycete was no longer in the mycelial state and hence receptive to phage infection. Lysogens were readily obtained in sterile amended soil; use of the spore extraction method and another method that isolated both spores and mycelia enabled lysogenic mycelia to be first detected after 2 days and lysogenic spores after 5 days. Phagemediated gene transfer of the thiostrepton-resistance gene from a lysogenic donor to a non-lysogenic recipient was also demonstrated in sterile amended soil. In nonsterile soil, host growth was considerably retarded with respect to sterile amended soil, although phage numbers showed a similar pattern with an initial burst of activity followed by subsequent decline. Lysogens were only rarely found in nonsterile soil and were also found to be less fit in situ than the parent strain. No difference was found in sterile amended soil.
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Padua, Roberto R. „Purification and characterization of an antimicrobial compound secreted by a soil bacterium /“. Abstract Full Text (HTML) Full Text (PDF), 2008. http://eprints.ccsu.edu/archive/00000530/02/1979FT.htm.
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Thesis (M.A.) -- Central Connecticut State University, 2008.Thesis advisor: Michael A. Davis. "... in partial fulfillment of the requirements for the degree of Master of Arts in Biomolecular Sciences." Includes bibliographical references (leaves 36-39). Also available via the World Wide Web.
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Mansoor, E. Y. „Immunological approaches to the ecology of Arthrobacter in soil“. Thesis, University of Essex, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315755.
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Caleb, Oluwafemi James. „Microbial community structure as an indicator of soil health in apple orchards“. Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4133.
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Thesis (MSc (Microbiology))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The relationship between various land management practices, soil properties and the soil microbial communities are complex and little is known about the effect of these interactions on plant productivity in agricultural systems. Although it would be advantageous to have a single organism or property that can be used as a measure of soil health, it may not be possible. Soil organisms which include both the microorganisms as well as soil fauna are subjected to the effect of their immediate environment. This microenvironment in turn is determined by the soil properties as well as above ground flora and their interactions. Most soil indicators interact with each other, and these interactions can modify or influence the soil properties. The complexities of the interactions between critical soil indicator values often preclude its practical use by land managers and policy makers. However, soil microbial communities (e.g. diversity and structural stability) may serve as a relative indicator of soil quality. These communities are sensitive to land management practices and changes in the microenvironment. The objective of this study was to gain an understanding of the complex relationships by investigating the effect of conventional, integrated and organic apple production systems on the physical, chemical and biological (particularly soil microbial diversity) properties of the soil. Automated Ribosomal Intergenic spacer analysis (ARISA) was used to characterise fungal (F-ARISA) and bacterial (B-ARISA) communities from soil samples obtained from an experimental apple orchard in Elgin, Grabouw. The intergenic spacer (ITS) region from the fungal rRNA operon was amplified using ITS4 and fluorescently FAM (6- carboxylfluorescein) labelled ITS5 primers. Similarly, the 16S-23S intergenic spacer region from the bacterial rRNA operon was amplified using ITSR and FAM-labelled ITSF primers. The sensitivity of the technique allowed us to discriminate between the soil microbial communities of the different treatments. From our results we observed significant increase (p < 0.05) in the fungal community diversity between the February and April samples, while the bacterial community diversity was consistent (p > 0.05). Also, treatments with mulch showed a significantly higher microbial diversity than the other treatments at a 5 % significance level. Fungal communities showed significant correlation with the potassium concentration in the soil, while bacterial communities depicted a significant correlation with the soil phosphorous concentration. Based on the results we concluded that different management practices have a significant effect on the soil microbial communities and that these communities are particularly sensitive to small changes in the environment. However, there is still a need to determine what the composition of the soil microbial communities are to be able to correlate our observations with soil health.
AFRIKAANSE OPSOMMING: Die verhouding tussen verskillende landboubestuurspraktyke, grondeienskappe en die mikrobiese gemeenskappe in grond is kompleks en weinig is bekend oor die uitwerking van hierdie interaksies op die produktiwiteit van landboustelsels. Alhoewel dit voordelig sou wees om ‘n enkele organisme of eienskap te kan hê wat die gesondheid van grond kan meet, sal dit dalk nie moontlik wees nie. Grondorganismes wat die mikroörganismes sowel as die grondfauna insluit, is onderworpe aan die invloed van hulle onmiddelike omgewings. Hierdie mikro-omgewings op hulle beurt word weer beïnvloed deur die grondeienskappe sowel as die die oppervlak flora en hulle wisselwerkinge. Meeste van die grondaanwysers toon ook wisselwerkinge met mekaar, en hierdie wisselwerkinge kan die grondeienskappe beïnvloed or selfs verander. Die kompleksiteit van die wisselwerkinge tussen kritiese grond aanwysers is meestal die rede waarom dit nie deur grondbestuurders en beleidsmakers gebruik word nie. Dit is ongeag die feit dat grond mikrobiese gemeenskappe (bv. diversiteit en stukturele stabiliteit) mag dien as ‘n relatiewe aanwyser van grondkwaliteit. Hierdie gemeenskappe is sensitief vir bestuurspraktyke en veranderinge in die mikro-omgewing. Die doel van die studie was om die ingewikkelde verhoudings in die grondgemeenskappe te bestudeer en die uitwerking van konventionele, geïntegreerde en organiese appel produksie sisteme op die fisiese, chemiese en biologiese eienskappe (veral die grond mikrobiologiese diversiteit) te bepaal. Geoutomatiseerde Ribosomale Intergeniese Spasie Analise (ARISA) is gebruik om die fungus (F-ARISA) en bakteriese (B-ARISA) gemeenskappe van grondmonsters wat vanaf ‘n proef appelboord in Elgin (Grabouw) verkry is, te bepaal. Die intergeenspasie (ITS) area van die fungus rDNA operon is vermeerder deur die ITS4 en fluoresserende FAM (6-karboxylfluorescein) gemerkte ITS5 inleiers te gebruik. Soortgelyk is die 16S-23S intergeenspasie area van die bakteriese rDNA operon vermeerder deur ITSR en FAM-gemerkte ITSF inleiers te gebruik. Die sensitiwiteit van die tegniek laat ons toe om te onderskei tussen die grond mikrobiese gemeenskappe vanaf verskillende grondbehandelings. Vanuit die resultate kon ons aflei dat daar ‘n toename (p < 0.05) in die fungus gemeenskap diversiteit vanaf Februarie to April was terwyl die bakteriese gemeenskap ‘n konstante diversteit getoon het (p > 0.05). Behandelings met grondbedekking het ook ‘n beduidend hoër mikrobiese diversiteit getoon as ander behandelings. Fungus gemeenskappe het beduidende korrelasies getoon met kalium konsentrasies in die grond, terwyl bakteriese gemeenskappe ‘n beduidende korrelasie getoon het met grond fosfor konsentrasies. Gebaseer op die resultate kon ons aflei dat verskillende bestuurspraktyke ‘n uitwerking kan hê op die grond mikrobiese gemeenskappe en dat hierdie gemeenskappe sensitief is vir klein veranderinge in die omgewing. Dit sal egter nog nodig wees om die spesifieke samestelling van die grond mikrobiese gemeenskappe te bepaal voor ons hierdie waarnemings kan korreleer met grondgesondheid.
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Kinneer, Krista L. „Size fractionation of bacterial functional diversity within soils“. Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1095.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 68 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 47-48).
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Lynch, Ryan P. „Controlling Soilborne Diseases of Potato and Influencing Soil Microbiology with Brassica Cover Crops“. Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/LynchRP2008.pdf.
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Moodley, Kamini. „Microbial diversity of Antarctic Dry Valley mineral soil“. Thesis, University of the Western Cape, 2004. http://etd.uwc.ac.za/index.php?module=etd&.
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Antarctica provides some of the most extreme environments on earth. Low temperatures, low water availability and nutrient deficiency are contributing factors to the limited colonisation of Antarctic biotopes, particularly in the continental Dry Valleys. The survival of microorganisms in this harsh continent provides the basis for the significance of this study. This study aimed to explore microbial phylotypic diversity across a 500 m altitudinal transect in the Miers Dry Valley, Ross Desert, East Antarctica. The study also attempted to infer from phylogenetic data, the possible presence of indicative phenotypes which might contribute to a functional microbial community.
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Rhode, Owen H. J. „Intraspecies diversity of Cryptococcus laurentii (Kufferath) C.E. Skinner and Cryptococcus podzolicus (Bab’eva & Reshetova) originating from a single soil sample“. Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1812.
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Thesis (MSc (Microbiology))--University of Stellenbosch, 2005.Intraspecific diversity among yeasts, including basidiomycetous yeasts has mostly been studied from a taxonomic point of view. The heterobasidiomycetous genus Cryptococcus is no exception and it was found to contain species that display heterogeneity both on a genetic and physiological level, i.e. diversity among strains originating from different geographical areas. It was stated that this diversity within yeast species is possibly caused by intrinsic attributes of the different habitats the strains of a particular species originate from. However, little is known about the diversity of a species within a specific habitat. Thus, in this study intraspecific diversity among selected cryptoccoci isolated from a single soil sample originating from pristine Fynbos vegetation , was investigated.
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Kumaresa, Deepak. „Molecular ecology of methanotrophs in a landfill cover soil“. Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/2771/.
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Landfills are a major anthropogenic source of methane and understanding the factors influencing the activity and diversity of methane oxidizing bacteria (methanotrophs) in landfill cover soil is critical to devise better landfill cover soil management strategies. A detailed study was carried out to investigate the effect of earthworms on soil methane oxidation potential and community structure of active methanotrophs in a landfill cover soil. Earthworms were found increase soil methane oxidation potential by 15% ± 7%. However, no substantial shifts in the community structure of active methanotrophs were observed. A Bacteroidetes-related bacterium was identified only in active bacterial community of earthworm-incubated landfill cover soil. However, its role in methane cycling is uncertain. In a subsequent study, a larger experimental system was used to simulate in situ landfill conditions and also to mimic the in situ environmental heterogeneity. A mRNA-based microarray analysis revealed that earthworm activity in landfill cover soil stimulates activity and diversity of Type I methanotrophs compared to Type II methanotrophs. Understanding spatio-temporal distribution pattern of microorganisms and the factors influencing their distribution pattern are integral for a better understanding of microbial functions in ecosystems. A pmoA-based microarray analysis of methanotroph community structure in a landfill cover soil revealed a temporal shift in methanotroph populations across different seasons. In the case of spatial distribution, only minor differences in methanotroph community structure were observed with no recognizable patterns. Correlation analysis between soil abiotic parameters (total C, N, NH4 +, NO3 - and water content) and distribution of methanotrophs revealed a lack of conclusive evidence for any distinct correlation pattern between measured abiotic parameters and methanotroph community structure, suggesting that complex interactions of several physic-chemical parameters shape methanotroph diversity and activity in landfill cover soils. A study was designed to investigate the shift in functional diversity of methanotrophs when microniches created by soil aggregates are physically altered. mRNA-based analysis of the bacterial transcription activity revealed an effect of physical disruption on active methanotrophs. The result emphasized that a change in a particular microbial niche need not be accompanied by an immediate change to the bacterial functional diversity and it depends on the ability of the bacterial communities to respond to the perturbation and perform the ecosystem function. DNA-SIP and mRNA based microarray techniques were compared for the assessment of active methanotroph community structure. Results from this study indicated that assessment of active methanotroph community structure by both the techniques were congruent. This suggested that the mRNA based microarray technique could be used to study active methanotroph community structure in situations where SIP experiments are not practical. However, both DNA-SIP and mRNA-microarray have their advantages and limitations and the selection of appropriate technique to assess active community structure depends on the nature of the study.
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Pino, Vanessa. „Soil Microbial Diversity Across Different Agroecological Zones in New South Wales“. Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16705.
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A synergistic relationship between soil diversity (pedodiversity) and soil microbial diversity (biodiversity) seems axiomatic. Soil microbes contribute with biogeochemical cycles on which rely soil services (e.g. food production) and; vice-versa the soil matrix provides the living conditions that structure its microbial communities. A better insight would enable us to quantify/qualify and so sustain, protect, and improve those processes underpinned by soil microorganisms. We hypothesize that the structural patterns of soil microbes rely on multivariate soil units and gradients (e.g. soil horizons) instead of single discrete ‘factors’ (soil pH) and that the microbial patterns can become a well-defined property of determined soils. We began exploring this biotic-abiotic dynamic by modeling soil microbial α-diversity using two orthogonal transects (~900 km each) across NSW. Soils were sampled from paired conserved and disturbed ecosystems. Soil biophysicochemistry was characterized using 16SrDNA/ITS metabarcoding and pedometric approaches. Soil microbial patterns and physicochemical attributes were assessed using linear and non-linear relationships (bootstraped regression trees models) whose output enabled the microbial mapping at 1km across NSW. These maps showed a higher diversity of soil microbes in western than eastern NSW. Despite this gradient, fungi and archaea were respectively lower and higher in Vertosols, whereas bacteria distribution was less clear. Our results suggested that microbial structural patterns relate to most pedological attributes and, the extent of this relationship varies according to the structural parameters analyzed (taxa composition, abundance, diversity metric). Therefore, microbial patterns are more consistent with grouped features defining soil gradients (soil types) rather than on individual soil properties. These conclusions will be supported by analyzing microbial and pedological dissimilarities (β-diversity) in a further research.
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Leech, Fiona. „Influence of alternative fertilizers on pasture production, soil properties and soil microbial community structure“. Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21460.
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Alternative fertilizers are commonly promoted for use on pastures to improve productivity and support a more ‘healthy’ soil microbial environment. However, minimal field research has been conducted to validate such claims. A 6-year study (2009–14) was conducted on phosphorus (P) deficient soils at three sites near Yass, NSW, to investigate the effect of top-dressing native perennial grass-based pastures with a range of alternative fertilizers and with single superphosphate (SSP). The alternative fertilizers included manures, composts, concentrated ash, crushed rock, rock phosphate-derived and microbial products. Annual measurements were made of soil chemical properties, pasture yield and botanical composition as well as relative effectiveness of products per unit of pasture grown. Soil microbial community structure was also analysed in the sixth year. Fertilizers with large quantities of P resulted in higher pasture production and clover content compared to the unfertilized control. Their cost-effectiveness in relation to pasture growth varied considerably and was a function of rate and frequency of application as well as amount and solubility of P applied. Despite large differences in pasture growth across the fertilizer treatments, there was no effect on microbial community structure compared with either the SSP or unfertilized controls. The observed variation in bacterial, fungal and archaeal community structures across all treatments was best explained by soil pH or aluminium concentration, which was influenced differentially by the fertilizer products. Fungal community structure was also correlated to pasture productivity parameters (i.e. pasture yield, clover percent and soil available P). These findings reveal a highly resilient soil microbial community influenced minimally by use of the alternative fertilizers, highlighting that on-farm management decisions regarding fertilizer product choice should primarily focus on pasture response and cost-effectiveness.
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Cartwright, Colin. „Biodegradation and impact of phthalate plasticisers on a soil microbial community“. Thesis, University of Kent, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264768.
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Burden, John P. „The survival, activity and distribution of gentamicin-producing Micromonospora in soil“. Thesis, University of Warwick, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302692.
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Kurtboke, Dilber Ipek. „New approaches to the isolation of non-streptomycete actinomycetes from soil“. Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314514.
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AraÃjo, Jackson de Lima. „Arthropods and attributes soil microbiology in fruit trees en Vale do Curu-CE, Brasil“. Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13481.
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A major concern related to agricultural management systems used by the man lies on the effects on biological processes in the soil, whose action within ecosystems aiming at the farm, modifies the intensity of these processes under use of techniques that exclusively aim to maximize crop yield. One of the challenges of research in soil biology is precisely understand the impacts on the complex interactions of all soil organisms at the community level by the management that are critical in maintaining soil quality. The objective of this work was to evaluate the influence of management practices on fruit trees (mango, guava and coconut trees) in the composition and distribution of soil arthropods (edaphic macrofauna, mesofauna) and on microbial biomass, the activity and interaction with the chemical, physical and environmental attributes. The study of soil arthropods began in July 2013 and followed until May 2014, with measurements at four periods. Microbiological soil activities were evaluated by the determination of microbial soil properties (RBS, CBM, NBM, NBM / N, qCO2 and qMIC). It was found that the soil arthropods were sensitive to changes arising from different soil tillage systems, allowing it to be used as an important tool to apply as bio-indicators of the quality of edaphic system. The system with guava cultivation proved to be unstable over time in relation to the structure of the community of soil arthropods. The system with coconut tree cultivation allows for better soil quality, increase in abundance and species richness of invertebrate macrofauna. The microbial biomass carbon (MBC), microbial biomass nitrogen (NBM) and the metabolic quotient (qCO2) were the main microbiological soil properties responsible for identifying dissimilarities between areas. Correlations between microbiological and faunal characteristics of the soil were low with significant correlations only between Collembola, NBM and NBM / N.Uma das grandes preocupaÃÃes relacionadas aos sistemas de manejo agrÃcola adotado pelo homem reside nos efeitos sobre os processos biolÃgicos que ocorrem no solo, cuja aÃÃo dentro dos ecossistemas visando à exploraÃÃo agrÃcola, modifica a intensidade desses processos em virtude do emprego de prÃticas que objetivam exclusivamente a maximizaÃÃo da produÃÃo vegetal. Um dos desafios da pesquisa em biologia do solo à justamente entender os impactos do manejo sobre as complexas interaÃÃes de todos os organismos edÃficos ao nÃvel de comunidade que sÃo fundamentais na manutenÃÃo da qualidade do solo. Objetivou-se avaliar a influÃncia dos manejos em cultivos de fruteiras (mangueira, goiabeira e coqueiro) na composiÃÃo e distribuiÃÃo dos artrÃpodes de solo (mesofauna e macrofauna edÃfica) e sobre a biomassa microbiana, sua atividade e interaÃÃo com os atributos quÃmicos, fÃsicos e ambientais. O estudo dos artrÃpodes edÃficos teve inÃcio em julho de 2013 e seguiu atà maio de 2014, com coletas realizadas em quatro perÃodos. As atividades microbiolÃgicas do solo foram avaliadas mediante as determinaÃÃes dos atributos microbianos do solo (RBS, CBM, NBM, NBM/N, qCO2 e qMIC). Constatou-se que os artrÃpodes de solo mostraram-se sensÃveis as alteraÃÃes ocasionadas pelos sistemas de manejos do solo, possibilitando a sua indicaÃÃo como importante ferramenta para aplicar-se como bioindicadores da qualidade do sistema edÃfico. O sistema com cultivo de goiabeiras mostrou-se instÃvel ao longo do tempo em relaÃÃo à estrutura da comunidade dos artrÃpodes de solo. O sistema com cultivo de coqueiros propicia melhores caracterÃsticas do solo e aumento na abundÃncia e riqueza de espÃcies da macrofauna invertebrada. O carbono da biomassa microbiana (CBM), nitrogÃnio da biomassa microbiana (NBM) e o quociente metabÃlico (qCO2), foram os principais atributos microbiolÃgicos do solo responsÃveis por identificar dissimilaridades entre as Ãreas. CorrelaÃÃes entre as variÃveis microbiolÃgicas e faunÃsticas do solo foram baixas, com correlaÃÃes significativas somente entre Collembola, NBM e NBM/N.
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Wang, Jing, und 王静. „Culture-independent analysis of anammox, AOA and AOB in paddy soil of Sanjiang Plain in Northeast China“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B4622158X.
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Walter, Diana Joyce, und dianawalter@internode on net. „The Environmental Impact of Genetically Modified Crop Plants on the Microbiology of the Rhizosphere“. Flinders University. Biotechnology, 2005. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20070301.161014.
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The effect of genetically modified crop plants on the microbiology of the rhizosphere was investigated using the single-gene Bt cotton as a case study. The project compared the rhizosphere microbiota of four Ingard® 1cotton plant varieties that were closely matched with their non-GM parental strains. The plants were grown in
three different Australian soils, ie, a vertisol from a cotton-growing region, and two soils, a fine sandy loam and a red sand from South Australia that had not been exposed to cotton.
At the time of the commencement of the project, the only commercially available genetically modified plants were cotton and carnations. The cotton industry in Australia is worth $1.5b annually, and care of the soil and the dynamics of its living microbial consortia needs to be understood for optimum management to enable
agricultural sustainability. The general outline of the thesis incorporated four main sections:
1. Experimental setup and analysis of the soils and plants to be used, quantification of the Cry1A(c) plant-produced Bt protein, and its
persistence in the soil environment.
2. Measurement of the selected microbial populations of bacteria, fungi, AMfungi,
protozoans and nematodes, by counting and estimation by dilution and most-probable number methods.
3. Assessment of selected metabolic pathways to determine the effects on the soil microbial community by chemical and other biochemical methods
4. An overall analysis between different group ratios of expression of each of the variables tested, and the summary of the risk analysis and conclusion.
The outcome of this work was the acquisition of scientific data to produce an environmental impact report. The findings of this study showed that generally the microbial populations and the products of major metabolic pathways correlated more closely within the non-GM and GM plant rhizospheres of the paired trials than those
of separate trials, indicating that soil and plant cultivar had a stronger environmental effect. The results obtained from the paired trials did not show that there were consistent effects on the rhizosphere soil microbiota that could be attributed to the presence of the Cry1A(c) Bt plant protein on the selected strains of cotton plants.
The results from the tests of the paired trials correlate highly with previously published work that the risk factors of genetically modified cotton plants on the microbiology of the rhizosphere soil were found be negligible and not consistent across trials.
1 ® Monsanto Co. St Louis, MO.
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Edvantoro, Bagus Bina. „Bioavailability, toxicity and microbial volatilisation of arsenic in soils from cattle dip sites“. Title page, Contents and Abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09A/09ae24.pdf.
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Quinones, Casilda. „Influence of three organic solvents on soil microbial activity“. Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_420_sip1_w.pdf&type=application/pdf.
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Barakat, Mohammad 1962. „Seasonal fluctuation in soil and thatch microbial populations in an 80%:20% sand:peat creeping bentgrass putting green“. Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277909.
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A study was conducted to determine the influence of a bio-organic amendment 'Greens Restore' (6N-1P-3K) and a nitrogen fertilizer (21N-7P-14K) on the microbial numbers, thatch degradation, and soil respiration. A complete randomized block design was used with 3 treatments/4 replications. Both treatments were applied at a rate of 28.6 kg N/ha every 60 and 30 days for the first and second year respectively. No significant changes were observed due to treatments for all the parameters measured except for soil fungi and thatch thickness. Control plots had the lowest and the fertilized plots had the highest values for both parameters. Microbial numbers showed significant differences with time except for the denitrifiers. Thatch bacterial, fungal, and actinomycetes numbers were greater than in soil. Two peaks in microbial numbers and soil respiration occurred in spring and autumn. Soil pH also changed with time and peaked in spring and autumn.
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Chapman, Joshua A. „Soil microbial communities from the alimentary canal of the earthworm Lumbricus terrestris (Oligochaeta: lumbricidae)“. Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4756.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains viii, 75 p. : ill. (some col.), map. Includes abstract. Includes bibliographical references.
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Millar, Neville. „The effect of improved fallow residue quality on nitrous oxide emissions from tropical soils“. Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268667.
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Woodward, Rebecca Stanton Wain. „Analysis of tetracycline resistance in compost bacilli“. Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259753.
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Johnson-Rollings, Ashley S. „A polyphasic approach to the study of chitinolytic bacteria in soil“. Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/51637/.
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Chitin is the most abundant nitrogen-containing polymer in nature, with >1x10 10 tonnes produced annually in terrestrial and marine habitats. Chitinolytic bacteria are able to degrade this recalcitrant substrate through a multiplicity of chitinases. A polyphasic approach was taken to studying these organisms within three diverse soil communities. Fluorometric assays employing 4-methylumbelliferyl-labelled chitinooligosaccharides were used to estimate basal soil chitinase activity as well as its chitinolytic potential in response to a- and b-chitin amendment. A molecular approach was adopted to profile the bacterial community and functional chi gene diversity within the soils. Finally, a method of exploring the metaexoproteome, enabling investigation of the dominant chitin degraders at a functional level, was developed and implemented. The metaexoproteome and metaproteome, extracted with an existing method, were compared and used to infer the functional dominance of chitinolytic phyla. The basal chitinase activity in all soils was found to be low, yet chitin amendment rapidly induced chitinases in all soils although intersite differences were seen. b-chitin amendment induced more chitinolytic activity in Cayo Blanco (CB) compared to Sourhope (SH). The Test Soil (TS), a site biannually amended with carapaces, retained higher chitinolytic potential many months after chitin had been consumed. Next-generation pyrosequencing enabled >50% of the potential OTUs present in the soil to be recovered. The 16S rRNA gene analysis of SH revealed dominant phyla to be Proteobacteria, Actinobacteria, and Acidobacteria with little change between amendments. The TS was dominated by the same phyla but saw a proliferation of Actinobacteria with chitin amendment. CB experienced the inverse response to the Test Soil, initially dominated by Actinobacteria only for Proteobacteria to dominate with amendment. Firmicutes were also prevalent with b-chitin amendment. Functional chi gene analysis found Streptomyces-like GH19 chi genes to dominate in both SH and CB. A rare Actinomycete Planobispora dominated chitin-amended TS. This organism is usually found in extremely arid soil. It was not found in the 16S rRNA gene analysis or the metaproteome; further analysis is required to confirm its presence. Streptomyces- like GH18 chi genes only dominated CB with amendment and were absent in SH. A large number of OTUs were identified as uncultured organisms suggesting a large pool of uncharacterized GH18 chi genes. Metaproteomics is the functional analysis of complex communities at a given point in time. The heterogeneity of soil, associated microbial communities, and presence of interfering compounds make the extraction of protein from soil a technical challenge. Chitinases are extracellular and so the metaexoproteome was targeted after development of a novel method that biased extraction towards exoproteins. The protocol successfully extracted the largest soil metaproteome to date. Actinobacterial chitinases were found to be functionally dominant in the Test Soil, especially in response to b-chitin amendment.
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Mueller, Sabrina R. „Chromium, DNA, and Soil Microbial Communities“. Cincinnati, Ohio : University of Cincinnati, 2006. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1141334651.
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Thesis (Ph. D.)--University of Cincinnati, 2008.Advisor: Brian K. Kinkle. Title from electronic thesis title page (viewed Apr. 23, 2009). Keywords: SEC-ICP-MS; Fungal community; bacterial community; DGGE. Includes abstract. Includes bibliographical references.
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Nielsen, Uffe Nygaard. „Influences on species richness and composition of belowground communities at multiple spatial scales“. Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=24811.
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Iker, Brandon Charles. „Application of Advanced Molecular Techniques in Applied Environmental Microbiology“. Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/301699.
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Recent advancements in molecular biology such as next generation sequencing and more sensitive and rapid molecular detection methods like qPCR, have historically been developed for clinical applications in human genetics and for health care diagnostic purposes. The high demand for faster and more accurate molecular assays in the health care field has driven rapid development of inexpensive molecular techniques that when applied to the science of environmental microbiology, provides an unprecedented level of understanding of the microbial world around us. The goal of this dissertation is to begin to apply more advanced molecular technologies to problems in applied environmental microbiology. Appendix A is a brief literature review of next generation sequencing technologies for applications in environmental microbiology. Appendix B focuses on the development of a more robust virus nucleic extraction kit for the detection of viral genomes from environmental samples found to contain high concentrations of qPCR inhibitors, such as humic acids or heavy metals. Appendix C summarizes one of the largest virus surveys done in the US, using state of the art qPCR technologies in both wastewater influent and effluent from two wastewater treatment plants in the Southwest. Data suggests that traditional virus indicators may not be a viable tool to evaluate fecally impacted source water or virus removal during water treatment. The third study summarized in Appendix D, provides one of the first insights into the microbial ecology of biofilms utilized as biological treatment media using Roche 454 amplicon sequencing of the 16S rRNA gene.
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Cundiff, Gary Thomas. „Using Arbuscular Mycorrhizae to Influence Yield, Available Soil Nutrients and Soil Quality in Conventional VS. Organic Vegetable Production“. TopSCHOLAR®, 2012. http://digitalcommons.wku.edu/theses/1155.
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This research is a two year study on the effects of endomycorrhizae on vegetable production using conventional vs. organic practices. Objective of this study was initiated to determine if mycorrhizae improve yield, available soil nutrients and soil quality from two different fertilizer sources. Measurements were taken on yield, available soil nutrients, and soil quality in comparison of glomalin production and soil loss percentage. Two plant species were chosen, Tomatoes (‘Big Beef’) and Bush Beans (‘Tenderette’). A randomized split block 2 x 3 factorial treatment arrangement was used with two crops and three different inputs: Mo- 0 mycorrhizae, M1- recommended rate, and M2- 2x recommended rate of mycorrhizae. Each mycorrhizal input was replicated three times in both the conventional and organic system. Results show there was no difference in yield based on mycorrhizae additions at any rate.
There was a significant yield difference based on conventional production over organic production in tomatoes and snap beans in 2010 and tomatoes in 2011. Possible explanations for yield difference in the organic production system include: different insect controls and a slower release of nutrients from poultry litter.
Available soil nutrients were not influenced in the study based on mycorrhizal inputs in inorganic or organic tomato production. Soil available nutrients were significantly influenced in organic tomato when compared to inorganic tomato production at selected sampling dates.
Mycorrhizae did not influence soil fertility in inorganic snap bean or organic snap bean production. Soil available nutrients were significantly influenced in organic snap bean when compared to inorganic snap bean production at selected sampling dates.
Glomalin production and soil loss percentage were not shown to be significantly different within organic or inorganic treatments based on mycorrhizae inputs. However, glomalin production was shown to be significantly greater in organic production compared to inorganic in 2011. An explanation of this could be due to the use of leaf mulch as organic weed control. Although a numerical decrease was observed in soil loss percentage in organic production compared to inorganic production from the first year to the second, it was not shown to be a significant amount.
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Parekh, Nisha Rajnikant Parekh. „New approaches to the selective isolation of wall chemotype IV actinomycestes from soil“. Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333669.
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Cogram, Kirstie J. „The effects of seaweed extracts on soilborne diseases, soil microbiology and the growth of wheat“. Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336244.
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Lanza, G. R., und Phillip R. Scheuerman. „Effect of Soil Amendments on In Situ Biodegradation in Creosote Contaminated Soils“. Digital Commons @ East Tennessee State University, 1996. https://dc.etsu.edu/etsu-works/2910.
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Davies, Nicholas Julian. „Microbial response to simulated climate change in Antarctic fellfield soil“. Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242859.
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