scholarly journals Bacterial physiological adaptations to contrasting edaphic conditions identified using landscape scale metagenomics

2017 ◽  
Author(s):  
Ashish A. Malik ◽  
Bruce C. Thomson ◽  
Andrew S. Whiteley ◽  
Mark Bailey ◽  
Robert I. Griffiths
Keyword(s):  
Alpha Diversity ◽  
Gamma Diversity ◽  
Organic C ◽  
Edaphic Conditions ◽  
Acquisition Strategies ◽  
Physiological Adaptations ◽  
Geographically Distributed ◽  
C And N ◽  
Functional Profiles ◽  
The Relationship

AbstractEnvironmental factors relating to soil pH are widely known to be important in structuring soil bacterial communities, yet the relationship between taxonomic community composition and functional diversity remains to be determined. Here, we analyze geographically distributed soils spanning a wide pH gradient and assess the functional gene capacity within those communities using whole genome metagenomics. Low pH soils consistently had fewer taxa (lower alpha and gamma diversity), but only marginal reductions in functional alpha diversity and equivalent functional gamma diversity. However, coherent changes in the relative abundances of annotated genes between pH classes were identified; with functional profiles clustering according to pH independent of geography. Differences in gene abundances were found to reflect survival and nutrient acquisition strategies, with organic-rich acidic soils harboring a greater abundance of cation efflux pumps, C and N direct fixation systems and fermentation pathways indicative of anaerobiosis. Conversely, high pH soils possessed more direct transporter-mediated mechanisms for organic C and N substrate acquisition. These findings show that bacterial functional versatility may not be constrained by taxonomy, and we further identify the range of physiological adaptations required to exist in soils of varying nutrient availability and edaphic conditions.

Carbon and nitrogen mineralization in soil treated with chloride and phosphate salts

1999 ◽  
Vol 79 (3) ◽  
pp. 427-429 ◽  
Author(s):  
D. Curtin ◽  
H. Steppuhn ◽  
C. A. Campbell ◽  
V. O. Biederbeck
Keyword(s):  
Organic Matter ◽  
Field Capacity ◽  
Organic C ◽  
Treated Soil ◽  
Carbon And Nitrogen ◽  
Inhibition Of Nitrification ◽  
Chloride Sulfate ◽  
C And N ◽  
Phosphate Salts ◽  
The Relationship

This study was undertaken to characterize the response of organic matter mineralization to soluble electrolyte concentration. We added salts (either KCl or KH2PO4) to a non-saline Black Chernozem at rates of 0 to 64 mmol kg−1 and measured the amounts of C and N mineralized in a 40 d incubation (21 °C and field capacity). Precipitation of calcium phosphate in KH2PO4-treated soil resulted in electrical conductivity (EC), measured in a 1:2 soil:water extract, being lower than in KCl-treated soil. Dissolved organic C (DOC) was increased (up to twofold) by KH2PO4 addition but KCl had little effect. The relationship between C mineralization and EC appeared to be independent of salt type. Mineralization decreased sharply (by 50%) when EC increased from 0.5 dS m−1 (check value) to 1.3 dS m−1. Inhibition of nitrification was not detected until EC increased to about 2 dS m–1. Key words: Mineralization, organic matter, salinity, chloride, sulfate

scholarly journals Uso de la tierra y diversidades alfa, beta y gamma de diplópodos en la cuenca del río Otún, Colombia

2010 ◽  
Vol 15 (1) ◽  
pp. 59 ◽  
Author(s):  
Darío Hernán Ruiz-Cobo ◽  
Julián Bueno-Villegas ◽  
Alexander Feijoo-Martínez
Keyword(s):  
Species Turnover ◽  
Alpha Diversity ◽  
Land Uses ◽  
Gamma Diversity ◽  
Crop Fields ◽  
Colombian Andes ◽  
Alpha Beta ◽  
Beta And Gamma Diversity ◽  
Del Rio ◽  
The Relationship

<p><strong></strong> <strong>Objective: </strong>To determine the relationship between changes in ecosystems and agrosystems provoked by human intervention and the alpha, beta and gamma diversity of the Diplopoda in the middle basin of the Otún river. <strong>Materials and methods: </strong>In this research we used a stratified systematic design with seven sampling windows and 16 sampling points. Millipedes were divided into families and morphotypes to calculate the alpha, beta and gamma diversity related to the heterogeneity of land uses. <strong>Results: </strong>We identified 35 morphotypes from 12 families and five orders. Alpha diversity of Diplopoda revealed significant differences between land uses (P &lt;0.05) and a decrease of richness from preserved areas to transformed areas by human activity. A high number of exclusive morphotypes were found in forest relicts and fallow with low species turnover between them, while the pastures, crop fields and plantations presented similar numbers of morphotypes but the species turnover between them was high (complementarity &gt; 85%) in spite of the low diversity in the land uses, which determined the high contribution of the beta diversity to the gamma diversity of the landscape. <strong>Conclusion: </strong>The heterogeneity of land uses showed that the changes modify the structure of diversity in Diplopoda with gradients diverging from the preserved ones to the highly transformed ones.</p> <p><strong>Key words: </strong>alpha, beta, gamma diversity, Colombian Andes, soil Diplopoda.</p><br />

Manipulation of rhizosphere organisms to enhance glomalin production and C sequestration: Pitfalls and promises

2014 ◽  
Vol 94 (6) ◽  
pp. 1025-1032 ◽  
Author(s):  
F. L. Walley ◽  
A. W. Gillespie ◽  
Adekunbi B. Adetona ◽  
J. J. Germida ◽  
R. E. Farrell
Keyword(s):  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Plant Growth Promoting Rhizobacteria ◽  
C Sequestration ◽  
Ionization Mass ◽  
Edge Structure ◽  
Organic C ◽  
Soil C ◽  
N Storage ◽  
C And N

Walley, F. L., Gillespie, A. W., Adetona, A. B., Germida, J. J. and Farrell, R. E. 2014. Manipulation of rhizosphere organisms to enhance glomalin production and C-sequestration: Pitfalls and promises. Can. J. Plant Sci. 94: 1025–1032. Arbuscular mycorrhizal fungi (AMF) reportedly produce glomalin, a glycoprotein that has the potential to increase soil carbon (C) and nitrogen (N) storage. We hypothesized that interactions between rhizosphere microorganisms, such as plant growth-promoting rhizobacteria (PGPR), and AMF, would influence glomalin production. Our objectives were to determine the effects of AMF/PGPR interactions on plant growth and glomalin production in the rhizosphere of pea (Pisum sativum L.) with the goal of enhancing C and N storage in the rhizosphere. One component of the study focussed on the molecular characterization of glomalin and glomalin-related soil protein (GRSP) using complementary synchrotron-based N and C X-ray absorption near-edge structure (XANES) spectroscopy, pyrolysis field ionization mass spectrometry (Py-FIMS), and proteomics techniques to characterize specific organic C and N fractions associated with glomalin production. Our research ultimately led us to conclude that the proteinaceous material extracted, and characterized in the literature, as GRSP is not exclusively of AMF origin. Our research supports the established concept that GRSP is important to soil quality, and C and N storage, irrespective of origin. However, efforts to manipulate this important soil C pool will remain compromised until we more clearly elucidate the chemical nature and origin of this resource.

scholarly journals Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Gustavo Pereira Duda ◽  
José Guilherme Marinho Guerra ◽  
Marcela Teixeira Monteiro ◽  
Helvécio De-Polli ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Vegetation Management ◽  
Pueraria Phaseoloides ◽  
Organic C ◽  
Arachis Pintoi ◽  
Factorial Combination ◽  
C And N ◽  
Microbial C ◽  
Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

Soil organic carbon and nitrogen sequestration and turnover in aggregates under subtropical leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 632 ◽  
Author(s):  
Kathryn Conrad ◽  
Ram C. Dalal ◽  
Ryosuke Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Soil Mass ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
Carbon And Nitrogen ◽  
Nitrogen Sequestration ◽  
C And N

Stabilisation and protection of soil organic carbon (SOC) in macroaggregates and microaggregates represents an important mechanism for the sequestration of SOC. Legume-based grass pastures have the potential to contribute to aggregate formation and stabilisation, thereby leading to SOC sequestration. However, there is limited research on the C and N dynamics of soil organic matter (SOM) fractions in deep-rooted legume leucaena (Leucaena leucocephala)–grass pastures. We assessed the potential of leucaena to sequester carbon (C) and nitrogen (N) in soil aggregates by estimating the origin, quantity and distribution in the soil profile. We utilised a chronosequence (0–40 years) of seasonally grazed leucaena stands (3–6 m rows), which were sampled to a depth of 0.3 m at 0.1-m intervals. The soil was wet-sieved for different aggregate sizes (large macroaggregates, >2000 µm; small macroaggregates, 250–2000 µm; microaggregates, 53–250 µm; and <53 µm), including occluded particulate organic matter (oPOM) within macroaggregates (>250 µm), and then analysed for organic C, N and δ13C and δ15N. Leucaena promoted aggregation, which increased with the age of the leucaena stands, and in particular the formation of large macroaggregates compared with grass in the upper 0.2 m. Macroaggregates contained a greater SOC stock than microaggregates, principally as a function of the soil mass distribution. The oPOM-C and -N concentrations were highest in macroaggregates at all depths. The acid nonhydrolysable C and N distribution (recalcitrant SOM) provided no clear distinction in stabilisation of SOM between pastures. Leucaena- and possibly other legume-based grass pastures have potential to sequester SOC through stabilisation and protection of oPOM within macroaggregates in soil.

scholarly journals Carbon and Nitrogen Stable Isotope Abundances and Soil Stoichiometry of Zanthoxylum Planispinum Var. Dintanensis Plantations at Different Ages

2021 ◽  
Author(s):  
Yanghua Yu ◽  
Yingu Wu ◽  
Yanping Song ◽  
Yitong Li
Keyword(s):  
Stable Isotope ◽  
Leaf Litter ◽  
Microbial Biomass Carbon ◽  
Guizhou Province ◽  
Soil C ◽  
Soil Microbial ◽  
Plantation Age ◽  
Soil Stoichiometry ◽  
C And N ◽  
The Relationship

Abstract Background and aimsUnderstanding the relationship between carbon, nitrogen and their stable isotope 13C, 15N and soil stoichiometry may assist to reveal the distribution pattern and stability mechanism of nutrient elements in karst ecosystem.MethodsFour plantations of Zanthoxylum planispinum var. dintanensis (5–7, 10–12, 20–22 and 30–32 years) in the karst plateau gorge area of Guizhou Province, China, were selected as the research objects to clarify the variation characteristics and interaction effects of leaf, litter, soil C, N and their isotopes with plantation age, and to explore the relationship between soil stoichiometry and the 13C, 15N of Zanthoxylum planispinum var. dintanensis plantation.Results(1) the 13C in leaf, litter and soil were − 28.04‰±0.59‰, -26.85‰±0.67‰ and − 19.39‰±1.37‰, respectively, correspondingly, the contents of 15N were 2.01‰±0.99‰, 2.91‰±1.32‰ and 3.29‰±0.69‰, respectively. The contents of the 13C and 15N can be rank ordered as soil > litter > leaf; (2) with the increase of plantation age, the soil 13C decreased; the leaf and litter 15N increased first then decreased; the litter 13C and soil 15N did not vary significantly; (3) the litter layer positively correlated to soil 13C, and negatively correlated to 15N; (4) redundancy analysis showed that soil microbial biomass carbon (MBC) and bacteria/fungi (BAC/FUN) were the dominant factors affecting C and N isotope natural abundances.ConclusionsThis study indicated that the species and acidity of soil microbial can affect the C and N isotope natural abundance.

scholarly journals Linking the lithogenic, atmospheric, and biogenic cycles of silicate, carbonate, and organic carbon in the ocean

2009 ◽  
Vol 6 (4) ◽  
pp. 6579-6599
Author(s):  
S. V. Smith ◽  
J.-P. Gattuso
Keyword(s):  
Carbon Storage ◽  
Chemical Weathering ◽  
Dissolved Inorganic Carbon ◽  
North Pacific Ocean ◽  
Atmospheric Co2 ◽  
Molar Ratio ◽  
Co2 Uptake ◽  
Organic C ◽  
Co2 Gas ◽  
The Relationship

Abstract. Geochemical theory describes long term cycling of atmospheric CO2 between the atmosphere and rocks at the Earth surface in terms of rock weathering and precipitation of sedimentary minerals. Chemical weathering of silicate rocks takes up atmospheric CO2, releases cations and HCO3− to water, and precipitates SiO2, while CaCO3 precipitation consumes Ca2+ and HCO3− and releases one mole of CO2 to the atmosphere for each mole of CaCO3 precipitated. At steady state, according to this theory, the CO2 uptake and release should equal one another. In contradiction to this theory, carbonate precipitation in the present surface ocean releases only about 0.6 mol of CO2 per mole of carbonate precipitated. This is a result of the buffer effect described by Ψ, the molar ratio of net CO2 gas evasion to net CaCO3 precipitation from seawater in pCO2 equilibrium with the atmosphere. This asymmetry in CO2 flux between weathering and precipitation would quickly exhaust atmospheric CO2, posing a conundrum in the classical weathering and precipitation cycle. While often treated as a constant, Ψ actually varies as a function of salinity, pCO2, and temperature. Introduction of organic C reactions into the weathering-precipitation couplet largely reconciles the relationship. ψ in the North Pacific Ocean central gyre rises from 0.6 to 0.9, as a consequence of organic matter oxidation in the water column. ψ records the combined effect of CaCO3 and organic reactions and storage of dissolved inorganic carbon in the ocean, as well as CO2 gas exchange between the ocean and atmosphere. Further, in the absence of CaCO3 reactions, Ψ would rise to 1.0. Similarly, increasing atmospheric pCO2 over time, which leads to ocean acidification, alters the relationship between organic and inorganic C reactions and carbon storage in the ocean. Thus, the carbon reactions and ψ can cause large variations in oceanic carbon storage with little exchange with the atmosphere.

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