59 research outputs found
Automated real-space lattice extraction for atomic force microscopy images
No full textAnalyzing atomically resolved images is a time-consuming process requiring solid experience and substantial human intervention. In addition, the acquired images contain a large amount of information such as crystal structure, presence and distribution of defects, and formation of domains, which need to be resolved to understand a material’s surface structure. Therefore, machine learning techniques have been applied in scanning probe and electron microscopies during the last years, aiming for automatized and efficient image analysis. This work introduces a free and open source tool (AiSurf: Automated Identification of Surface Images) developed to inspect atomically resolved images via scale-invariant feature transform and clustering algorithms. AiSurf extracts primitive lattice vectors, unit cells, and structural distortions from the original image, with no pre-assumption on the lattice and minimal user intervention. The method is applied to various atomically resolved non-contact atomic force microscopy images of selected surfaces with different levels of complexity: anatase TiO2(101), oxygen deficient rutile TiO2(110) with and without CO adsorbates, SrTiO3(001) with Sr vacancies and graphene with C vacancies. The code delivers excellent results and is tested against atom misclassification and artifacts, thereby facilitating the interpretation of scanning probe microscopy images
Identification of specific interactions between bacteria and heavy metals accumulating plants
No full textEffects of natural and NH4-charged zeolite amendments and their combination with 3,4-dimethylpyrazole phosphate (DMPP) on soil gross ammonification and nitrification rates
No full textNo abstract availabl
Interactions between accumulation of trace elements and macronutrients in Salix caprea after inoculation with rhizosphere microorganisms.
No full textAlthough the beneficial effects on growth and trace element accumulation in Salix spp. inoculated with
microbes are well known, little information is available on the interactions among trace elements and
macronutrients. The main purpose of this study was to assess the effect of phytoaugmentation with
the rhizobacteria Agromyces sp., Streptomyces sp., and the combination of each of them with the fungus
Cadophora finlandica on biomass production and the accumulation of selected trace elements (Zn, Cd, Fe)
and macronutrients (Ca, K, P and Mg) in Salix caprea grown on a moderately polluted soil. Dry matter production
was significantly enhanced only upon inoculation with Agromyces sp. Regarding the phytoextraction
of Cd and Zn, shoot concentrations were mostly increased after inoculation with Streptomyces sp. and
Agromyces sp. + C. finlandica. These two treatments also showed higher translocation factors from roots to
the leaves for both Cd and Zn. The accumulation of Cd and Zn in shoots was related to increased concentrations
of K. This suggests that microorganisms that contribute to enhanced phytoextraction of Cd and
Zn affect also the solubility and thus phytoavailability of K. This study suggests that the phytoextraction
of Zn and Cd can be improved by inoculation with selected microbial strains
EXPLORING NUTRIENT RECYCLING POTENTIAL OF STRUVITE AND ZEOLITES IN SOIL: INSIGHTS ON IMMEDIATE CARBON AND NITROGEN DYNAMICS
No full textAmplitude and frequency of wetting and drying cycles drive N2 and N2O emissions from a subtropical pasture
No full textThis study investigated the effects of irrigation frequency on N2 and N2O emissions from an intensively managed pasture in the subtropics. Irrigation volumes were estimated to replace evapotranspiration and were applied either once (low frequency) or split into four applications (high frequency). To test for legacy effects, a large rainfall event was simulated at the end of the experiment. Over 15 days, 7.9 ± 2.7 kg N2 + N2O-N ha−1 was emitted on average regardless of irrigation frequency, with N2O accounting for 25% of overall N2 + N2O. Repeated, small amounts of irrigation produced an equal amount of N2 + N2O losses as a single, large irrigation event. The increase in N2O emissions after the large rainfall event was smaller in the high-frequency treatment, shifting the N2O/(N2O + N2) ratio towards N2, indicating a treatment legacy effect. Cumulative losses of N2O and N2 did not differ between treatments, but higher CO2 emissions were observed in the high-frequency treatment. Our results suggest that the increase in microbial activity and related O2 consumption in response to small and repeated wetting events can offset the effects of increased soil gas diffusivity on denitrification, explaining the lack of treatment effect on cumulative N2O and N2 emissions and the abundance of N cycling marker genes. The observed legacy effect may be linked to increased mineralisation and subsequent increased dissolved organic carbon availability, suggesting that increased irrigation frequency can reduce the environmental impact (N2O), but not overall magnitude of N2O and N2 emissions from intensively managed pastures
Culturable bacteria from Zn- and Cd-accumulating Salix caprea with differential effects on plant growth and heavy metal availability.
No full textAims: To characterize bacteria associated with Zn ⁄ Cd-accumulating Salix
caprea regarding their potential to support heavy metal phytoextraction.
Methods and Results: Three different media allowed the isolation of 44 rhizosphere
strains and 44 endophytes, resistant to Zn ⁄Cd and mostly affiliated with
Proteobacteria, Actinobacteria and Bacteroidetes ⁄ Chlorobi. 1-Aminocyclopropane-
1-carboxylic acid deaminase (ACCD), indole acetic acid and siderophore
production were detected in 41, 23 and 50% of the rhizosphere isolates and in
9, 55 and 2% of the endophytes, respectively. Fifteen rhizosphere bacteria and
five endophytes were further tested for the production of metal-mobilizing
metabolites by extracting contaminated soil with filtrates from liquid cultures.
Four Actinobacteria mobilized Zn and ⁄ or Cd. The other strains immobilized
Cd or both metals. An ACCD- and siderophore-producing, Zn ⁄ Cd-immobilizing
rhizosphere isolate (Burkholderia sp.) and a Zn ⁄ Cd-mobilizing Actinobacterium
endophyte were inoculated onto S. caprea. The rhizosphere isolate
reduced metal uptake in roots, whereas the endophyte enhanced metal accumulation
in leaves. Plant growth was not promoted.
Conclusions: Metal mobilization experiments predicted bacterial effects on
S. caprea more reliably than standard tests for plant growth-promoting activities.
Significance and Impact of the Study: Bacteria, particularly Actinobacteria,
associated with heavy metal-accumulating Salix have the potential to increase
metal uptake, which can be predicted by mobilization experiments and may be
applicable in phytoremediation
Aldo Gorfer e la cultura alpina
No full textBilancio storiografico delle ricerche di un autorevole studioso e pubblicista trentin
Recycling nitrogen from liquid digestate via novel reactive struvite and zeolite minerals to mitigate agricultural pollution
No full textRecycling nutrients is of paramount importance. For this reason, struvite and nitrogen enriched zeolite fertilizers produced from wastewater treatments are receiving growing attention in European markets. However, their effects on agricultural soils are far from certain, especially struvite, which only recently was implemented in EU Fertilizing Product Regulations. In this paper, we investigate the effects of these materials in acid sandy arable soil, particularly focusing on N dynamics, evaluating potential losses, transformation pathways, and the effects of struvite and zeolitic tuffs on main soil biogeochemical parameters, in comparison to traditional fertilization with digestate. Liming effect (pH alkalinization) was observed in all treatments with varying intensities, affecting most of the soil processes. The struvite was quickly solubilized due to soil acidity, and the release of nutrients stimulated nitrifying and denitrifying microorganisms. Zeolitic tuff amendments decreased the NOx gas emissions, which are precursors to the powerful climate altering N2O gas, and the N enriched chabazite tuff also recorded smaller NH3 emissions compared to the digestate. However, a high dosage of zeolites in soil increased NH3 emissions after fertilization, due to pronounced pH shifts. Contrasting effects were observed between the two zeolitic tuffs when applied as soil amendments; while the chabazite tuff had a strong positive effect - increasing up to ∼90% the soil microbial N immobilization - the employed clinoptilolite tuff had immediate negative effects on the microbial biomass, likely due to the large quantities of sulphur released. However, when applied at lower dosages, the N enriched clinoptilolite also contributed to the increase of microbial N. From these outcomes, we confirm the potential of struvite and zeolites to mitigate the outfluxes of nutrients from agricultural systems. To gain the best results and significantly lower environmental impacts, extension practitioners could give recommendations based on the soils that are planned for zeolite application
Effect of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on N-turnover, the N2O reductase-gene nosZ and N2O:N2 partitioning from agricultural soils
No full textNitrification inhibitors (NIs) have been shown to reduce emissions of the greenhouse gas nitrous oxide (N2O) from agricultural soils. However, their N2O reduction efficacy varies widely across different agro-ecosystems, and underlying mechanisms remain poorly understood. To investigate effects of the NI 3,4-dimethylpyrazole-phosphate (DMPP) on N-turnover from a pasture and a horticultural soil, we combined the quantification of N2 and N2O emissions with 15N tracing analysis and the quantification of the N2O-reductase gene (nosZ) in a soil microcosm study. Nitrogen fertilization suppressed nosZ abundance in both soils, showing that high nitrate availability and the preferential reduction of nitrate over N2O is responsible for large pulses of N2O after the fertilization of agricultural soils. DMPP attenuated this effect only in the horticultural soil, reducing nitrification while increasing nosZ abundance. DMPP reduced N2O emissions from the horticultural soil by >50% but did not affect overall N2 + N2O losses, demonstrating the shift in the N2O:N2 ratio towards N2 as a key mechanism of N2O mitigation by NIs. Under non-limiting NO3− availability, the efficacy of NIs to mitigate N2O emissions therefore depends on their ability to reduce the suppression of the N2O reductase by high NO3− concentrations in the soil, enabling complete denitrification to N2
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