Metal and metalloid foliar uptake by various plant species exposed to atmospheric industrial fallout: Mechanisms involved for lead

Fine and ultrafine metallic particulatematters (PMs) are emitted frommetallurgic activities in peri-urban zones into the atmosphere and can be deposited in terrestrial ecosystems. The foliar transfer ofmetals andmetalloids and their fate in plant leaves remain unclear, although this way of penetration may be a major contributor to the transfer of metals into plants. This study focused on the foliar uptake of various metals and metalloids from enriched PM(Cu, Zn, Cd, Sn, Sb, As, and especially lead (Pb)) resulting fromthe emissions of a battery-recycling factory.Metal and metalloid foliar uptake by various vegetable species, exhibiting different morphologies, use (food or fodder) and life-cycle (lettuce, parsley and rye-grass) were studied. The mechanisms involved in foliar metal transfer from atmospheric particulate matter fallout, using lead (Pb) as a model element was also investigated. Several complementary techniques (micro-X-ray fluorescence, scanning electron microscopy coupled with energy dispersive X-ray microanalysis and time-of-flight secondary ion mass spectrometry) were used to investigate the localization and the speciation of lead in their edible parts, i.e. leaves. The results showed lead-enriched PM on the surface of plant leaves. Biogeochemical transformations occurred on the leaf surfaces with the formation of lead secondary species (PbCO3 and organic Pb). Some compounds were internalized in their primary form (PbSO4) underneath an organic layer. Internalization through the cuticle or penetration through stomata openings are proposed as two major mechanisms involved in foliar uptake of particulate matter

Early Struggles for Bilingual Schools and the French Language in the Windsor Border Region, 1851–1910

In 1910, Bishop Michael Fallon of London called for the abolition of the bilingual schools of Ontario because of their inefficiencies. Concerns about the value of a bilingual education and the French language in particular predate Fallon and go back to the 1850s in the Windsor border region. These concerns were voiced by both francophones and Anglophones, and illustrate that the struggle for the survival of the French language in the churches and schools of the area predated the arrival of Fallon and the Ontario government’s imposition of Regulation XVII

Variable selection in near infrared spectra for the biological characterization of soil and earthworm casts

International audienceNear infrared reflectance spectroscopy (NIRS) was used to predict six biological properties of soil and earthworm casts including extracellular soil enzymes, microbial carbon, potential nitrification and denitrification. Partial least squares regression (PLSR) models were developed with a selection of the most important near infrared wavelengths. They reached coefficients of determination ranging from 0.81 to 0.91 and ratios of performance-to-deviation above 2.3. Variable selection with the variable importance in the projection (VIP) method increased dramatically the prediction performance of all models with an important contribution from the 1750–2500 nm region. We discuss whether selected wavelengths can be attributed to macronutrient availability or to microbial biomass. Wavelength selection in NIR spectra is recommended for improving PLSR models in soil research

Spatial biases reduce the ability of Earth system models to simulate soil heterotrophic respiration fluxes

Heterotrophic respiration (Rh) is, at a global scale, one of the largest CO2 fluxes between the Earth's surface and atmosphere and may increase in the future. The previous generation of Earth system models (ESMs) was able to reproduce global fluxes relatively well, but at that, time no gridded products were available to perform an in-depth evaluation. The capacity of the new generation of ESMs used within the Coupled Model Intercomparison Project Phase 6 (CMIP6) to reproduce this flux has not been evaluated, meaning that the realism of resulting CO2 flux estimates is unclear. In this study, we combine recently released observational data on Rh and ESM simulations to evaluate the ability of 13 ESMs from CMIP6 to reproduce Rh. Only 4 of the 13 tested ESMs were able to reproduce the total Rh flux, but spatial analysis underlined important bias compensation for most of the ESMs, which generally showed an overestimation in tropical regions and an underestimation in arid regions. To identify the main drivers of the bias, we performed an analysis of the residuals and found that mean annual precipitation was the most important driver explaining the difference between ESM simulations and observation-derived products of Rh, with a higher bias between ESM simulations and Rh products where precipitation was high. Based on our results, next-generation ESMs should focus on improving the response of Rh to soil moisture.</p

Contribution à la topographie antique de Lugdunum : la porte monumentale et l’espace funéraire du site de la montée de la Butte

L’article concerne le site antique de la montée de la Butte à Lyon fouillé en 2001, situé sur la rive gauche de la Saône, à l’angledu quai Saint-Vincent et de la montée de la Butte, dans le premier arrondissement. Il traite des dernières phases d’occupation du site, caractérisées par la construction d’une porte monumentale, le creusement d’un fossé et l’installation d’un espace funéraire dans le courant du iie s.La porte contrôlait une voie longeant la rive gauche de la Saône et délimitait un espace urbain dont l’étendue et le statut sont difficiles à préciser. Associée à une enceinte, cette porte était-elle essentiellement symbolique ou s’agissait-il d’un ensemble architectural exclusivement défensif ? Outre l’intérêt considérable qu’apporte la découverte inédite d’un élément de l’enceinte de Lugdunum, l’étude de l’espace funéraire a fourni des données qui viennent enrichir le corpus des ensembles funéraires périurbains antiques lyonnais.La porte et l’ensemble funéraire sont abandonnés autour de la seconde moitié du ve s. et un four à chaux est construit pour transformer les matériaux calcaires de l’élévation du monument.This paper deals with the Roman site of la Montée de la Butte excavated in 2001 and located on the left bank of the Saône, at the corner of the Saint Vincent quay and the “Montée de la Butte” in Lyon’s first arrondissement. It centres on the last phases of the site characterized by the building of a monumental archway, the digging of a ditch and the founding of a cemetery during the 2nd century AD.The archway controlled a road that ran along the left bank of the Saône and delimited the urban area the expanse and status of which are not known. The archway can be linked to the urban enclosure, but was this ensemble only symbolic or was it an architectural construction for defensive purposes ? In addition to the considerable interest aroused by the discovery of an element of Lugdunum’s city enclosure, the study of the burial area has significantly enriched the funerary data from peripheral Roman cemeteries. The archway and the burial area fell into disuse around the second half of the 5th century AD and a lime oven was built in order to transform the limestone blocks from the monument into quicklime.Gegenstand dieses Artikels ist die 2001 ausgegrabene Fundstätte Montée de la Butte in Lyon auf dem linken Ufer der Saône im 1. Arrondissement, dort, wo die Montée de la Butte auf das Quai Saint-Vincent stößt. Er behandelt die letzten Siedlungsphasen, die durch den Bau eines monumentalen Tors, den Aushub eines Grabens und die Installation eines Grabbereichs im Laufe des 2. Jh. gekennzeichnet sind.Das Tor kontrollierte eine Straße, die am linken Ufer der Saône entlangführte und begrenzte ein städtisches Areal, dessen Ausmaß und Status schwierig zu bestimmen sind. Spielte das zu einer Stadtmauer gehörige Tor hauptsächlich eine symbolische Rolle ? oder handelte es sich um ein Bauwerk mit ausschließlich defensivem Charakter ? Abgesehen von dem Stellenwert der Entdeckung eines Elements der Stadtmauer von Lugdunum haben die bei der Erforschung des Grabbereiches gewonnenen Informationen das Corpus der antiken stadtnahen Nekropolen bereichert.Das Tor und der Friedhof werden um die zweite Hälfte des 5. Jh. aufgegeben und es wird ein Kalkofen für die Verarbeitung der Kalksteine des Bauwerks gebaut

Cournon-d’Auvergne – Carré du Buisson (lotissement Bois Joli 2)

Identifiant de l'opération archéologique : 2006/78 Date de l'opération : 2007 (EX) La commune de Cournon d’Auvergne, située à quelque5km au sud-est de Clermont-Ferrand, s’inscrit entre la grande plaine de La Limagne au nord, la dépression du bassin de Sarliève à l’ouest, bordé lui-même par des collines calcaires et la rivière Allier à l’est. Elle se situe donc au débouché du bassin de l’Allier vers la plaine. Le bassin de Sarliève, qui intéresse plus particulièrement, notre dossier est dominé..

Soil fungal community shift evaluation as a potential cadaver decomposition indicator

Fungi metabolise organic matter in situ and so alter both the bio-/physico-chemical properties and microbial community structure of the ecosystem. In particular, they are responsible reportedly for specific stages of decomposition. Therefore, this study aimed to extend previous bacteria-based forensic ecogenomics research by investigating soil fungal community and cadaver decomposition interactions in microcosms with garden soil (20 kg, fresh weight) and domestic pig (Sus scrofa domesticus) carcass (5 kg, leg). Soil samples were collected at depths of 0–10 cm, 10–20 cm and 20–30 cm on days 3, 28 and 77 in the absence (control −Pg) and presence (experimental +Pg) of Sus scrofa domesticus and used for total DNA extraction and nested polymerase chain reaction and denaturing gradient gel electrophoresis (PCR–DGGE) profiling of the 18S rRNA gene. The Shannon–Wiener (H′) community diversity indices were 1.25 ± 0.21 and 1.49 ± 0.30 for the control and experimental microcosms, respectively, while comparable Simpson species dominance (S) values were 0.65 ± 0.109 and 0.75 ± 0.015. Generally, and in contrast to parallel studies of the bacterial 16S rRNA and 16S rDNA profiles, statistical analysis (t-test) of the 18S dynamics showed no mathematically significant shifts in fungal community diversity (H′; p = 0.142) and dominance (S; p = 0.392) during carcass decomposition, necessitating further investigations

Soil organic carbon models need independent time-series validation for reliable prediction

Numerical models are crucial to understand and/or predict past and future soil organic carbon dynamics. For those models aiming at prediction, validation is a critical step to gain confidence in projections. With a comprehensive review of ~250 models, we assess how models are validated depending on their objectives and features, discuss how validation of predictive models can be improved. We find a critical lack of independent validation using observed time series. Conducting such validations should be a priority to improve the model reliability. Approximately 60% of the models we analysed are not designed for predictions, but rather for conceptual understanding of soil processes. These models provide important insights by identifying key processes and alternative formalisms that can be relevant for predictive models. We argue that combining independent validation based on observed time series and improved information flow between predictive and conceptual models will increase reliability in predictions

Climate change effects on the stability and chemistry of soil organic carbon pools in a subalpine grassland

Mountain soils stock large quantities of carbon as particulate organic matter that may be highly vulnerable to climate change. To explore potential shifts in soil organic matter (SOM) form and stability under climate change (warming and reduced precipitations), we studied the dynamics of SOM pools of a mountain grassland in the Swiss Jura as part of a climate manipulation experiment. The climate manipulation (elevational soil transplantation) was set up in October 2009 and simulated two realistic climate change scenarios. After 4 years of manipulation, we performed SOM physical fractionation to extract SOM fractions corresponding to specific turnover rates, in winter and in summer. Soil organic matter fraction chemistry was studied with ultraviolet, 3D fluorescence, and mid-infrared spectroscopies. The most labile SOM fractions showed high intra-annual dynamics (amounts and chemistry) mediated via the seasonal changes of fresh plant debris inputs and confirming their high contribution to the microbial loop. Our climate change manipulation modified the chemical differences between free and intra-aggregate organic matter, suggesting a modification of soil macro-aggregates dynamics. Interestingly, the 4-year climate manipulation affected directly the SOM dynamics, with a decrease in organic C bulk soil content, resulting from significant C-losses in the mineral-associated SOM fraction (MAOM), the most stable form of SOM. This SOC decrease was associated with a decrease in clay content, above- and belowground plants biomass, soil microbial biomass and activity. The combination of these climate changes effects on the plant–soil system could have led to increase C-losses from the MAOM fraction through clay-SOM washing out and DOC leaching in this subalpine grassland