Microcalorimetric study of some Amazonian soils

Barros, Nieves; Feijóo, Sergio; Simoni, José A.; Prado, Alexandre G.S.; Barboza, Fernando D.; Airoldi, Cláudio

doi:10.1016/s0040-6031(98)00629-7

Cited by 50 publications

(25 citation statements)

References 14 publications

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“…1 synthetic medium for actinomycetes. The population of living microorganisms (N 0 ) was estimated by a viable count on serial spread plates (Barros et al, 1999;Shatalin et al, 2008). A series of 10-fold dilutions of the samples were prepared with 90 ml of sterilized de-ionized water and 10.0 g of the soil samples.…”

Section: Biological Properties Determinationmentioning

confidence: 99%

Simple heat profiles and biogeochemical patterns for analysis the influence on soil microbial community of plastic-greenhouse and open field condition

et al. 2018

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The diversity of the soil microbial community is remarkably sensitive to different cropping techniques. To examine the effects of cultivation in a greenhouse on the soil microbial activity and diversity, we collected soil samples from vegetable crops continuously grown in a plastic greenhouse (G) and an open field (N). Heat profiling was obtained using microcalorimeter in the presence of different carbon sources. Power time curves were recorded after glucose and ammonium sulphate supplementation. The total heat release QT (Jg-1), maximum heat flow Pmax (μW) and growth rate constant k (h-1) are higher in G treatment group than the in N treatment group. On the other hand, the time (tmax) to reach the peak heat flow is lower in G treatment group compared to N treatment group, as is cell specific heat rate JQ/N (J cell-1). Sample G1 has the highest Pmax (1246.07 μW) and the lowest tmax (11.86 h); in contrast, sample N5 has the lowest Pmax (411.03 μW) and the highest tmax (21.78 h). The microbial community in the soil was estimated from phospholipid fatty acid (PLFA) biomarkers analysis and a viable count, followed by a subsequent determination of the physicochemical parameters. The total average PLFA concentration range is found as 129.76 - 142.54 nmol g-1. Both thermodynamics properties and PLFA concentration was are significantly greater in G1, G2 and G3 treatment than in the other two (N5 & N6) management systems (P < 0.05). Combination of both thermodynamic and PLFA profiling determines that the microbial population is higher in the soil from the greenhouse fertilization than from the open field cultivation. This novel approach could be applicable to a better understanding of (i) the changes in the soil microbial community in green house and open field cultivation practices, and (ii) the relationship between physicochemical properties and soil microbial community’s diversity. Moreover, this would be a notable technique for the decision maker to choose the potential cultivation method for sustainable green-food development program.

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Section: Biological Properties Determinationmentioning

confidence: 99%

Simple heat profiles and biogeochemical patterns for analysis the influence on soil microbial community of plastic-greenhouse and open field condition

et al. 2018

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“…Apparent microbial growth rate and generation time were calculated for the different carbon sources according to the method previously described in Kimura and Takahashi (1985) and in Barros et al (1999).…”

Section: Measurement Of Microbial Activities In Moonmilkmentioning

confidence: 99%

Microbiological activities in moonmilk monitored using isothermal microcalorimetry (Cave of Vers chez le Brandt, Neuchatel, Switzerland)

Braissant¹,

Bindschedler²,

Daniels³

et al. 2012

JCKS

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Studies of the influence of microbial communities on calcium carbonate deposits mostly rely on classical or molecular microbiology, isotopic analyses, and microscopy. Using these techniques, it is difficult to infer microbial activities in such deposits. In this context, we used isothermal microcalorimetry, a sensitive and nondestructive tool, to measure microbial activities associated with moonmilk ex-situ. Upon the addition of diluted LB medium and other carbon sources to fresh moonmilk samples, we estimated the number of colony forming units per gram of moonmilk to be 4.8 3 10 5 6 0.2 3 10 5 . This number was close to the classical plate counts, but one cannot assume that all active cells producing metabolic heat were culturable. Using a similar approach, we estimated the overall growth rate and generation time of the microbial community associated with the moonmilk upon addition of various carbon sources. The range of apparent growth rates of the chemoheterotrophic microbial community observed was between 0.025 and 0.067 h 21 and generation times were between 10 and 27 hours. The highest growth rates were observed for citrate and diluted LB medium, while the highest carbon-source consumption rates were observed for low molecular weight organic acids (oxalate and acetate) and glycerol. Considering the rapid degradation of organic acids, glucose, and other carbon sources observed in the moonmilk, it is obvious that upon addition of nutrients during snow melting or rainfall these communities can have high overall activities comparable to those observed in some soils. Such communities can influence the physico-chemical conditions and participate directly or indirectly to the formation of moonmilk.

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“…The samples were collected from a depth of 5-10 cm, after removal of the top surface layer 13 . The samples were air dried for thirty days and homogenized by sieving, less than 2 mm 14 .…”

Section: Soil Samplesmentioning

confidence: 99%

Monitoring of the harmful concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) in soils with and without organic matter

Prado¹,

Vieira²,

Rezende³

2001

J. Braz. Chem. Soc.

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Os pesticidas têm sido usados para eliminar formas indesejáveis de vida nocivas à agricultura ou em áreas urbanas. O êxodo rural e, conseqüentemente, o aumento de preço da mão-de-obra remanescente nas áreas agrícolas levaram a um aumento do uso de herbicidas nas lavouras, principalmente do 2,4-D. Através de processos de adsorção-dessorção a mobilidade do herbicida 2,4-D pode ser avaliada. A contribuição da matéria orgânica do solo foi avaliada no processo de sorção do referido herbicida, constatando-se que a mesma contribui para o aumento de sua adsorção. A concentração ideal de 2,4-D a ser aplicada em um solo tipo latossolo roxo foi determinada através de experimentos de adsorção-dessorção.Agrochemicals have been used to eliminate different undesirable forms of life both in agriculture and in urban areas. The rural exodus and the increase of labor costs in the agricultural areas have induced a greater use of herbicides in crops, mainly of 2,4-D. Through adsorption-desorption processes the mobility of this herbicide can be evaluated. The effect of organic matter on sorption of 2,4-D in soil has been studied. Organic matter contributed to the increase of 2,4-D adsorption. The ideal concentrations of 2,4-D in yellow-red Latosol soils were determined based on adsorptiondesorption experiments.

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Microcalorimetric study of some Amazonian soils

Cited by 50 publications

References 14 publications

Simple heat profiles and biogeochemical patterns for analysis the influence on soil microbial community of plastic-greenhouse and open field condition

Simple heat profiles and biogeochemical patterns for analysis the influence on soil microbial community of plastic-greenhouse and open field condition

Microbiological activities in moonmilk monitored using isothermal microcalorimetry (Cave of Vers chez le Brandt, Neuchatel, Switzerland)

Monitoring of the harmful concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) in soils with and without organic matter

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