Uptake and surface chemistry of SO2 on natural volcanic dusts

V-dust (v-dust) is a highly variable source of natural particles in the atmosphere, and during the period of high volcanic activity it can provide a large surface for heterogeneous interactions with other atmospheric compounds. Icelandic v-dust was chosen as a case study due to frequency of volcanic eruptions and high aeolian activity in the area. In this study, we focus on the kinetics and mechanism of the reaction of sulfur dioxide (SO2) with natural v-dust samples under atmospheric conditions using coated wall flow tube reactor and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Steady state uptake coefficients determined are in the range of 10−9 to 10−8 depending on the considered v-dust. Concomitantly with SO2 uptake, both sulfites and sulfates are monitored on the surface of v-dust, with sulfates being the final oxidation product, attesting of SO2 surface reaction. Surface hydroxyl groups play a crucial role in the conversion of SO2 to sulfites as evidenced from both flow tube and DRIFTS experiments. Based on these experimental results, a mechanism for SO2 interaction with different surface sites of v-dust is proposed and discussed. This study provides original insights in the kinetics of SO2 uptake under simulated atmospheric conditions and its mechanism and transformation on volcanic material. To that regards, it brings an accurate perspective on SO2 heterogeneous sinks in the atmosphere.The authors acknowledge Mr Vincent Gaudion and Dr Mohamad Zeineddine (SAGE, IMT Lille Douai) for their assistance in the lab. We are grateful to Mr Bruno Malet and Dr Laurent Alleman (SAGE, IMT Lille Douai) for conducting the ICP-MS experiments. This work was achieved in the frame of Labex CaPPA, funded by ANR through the PIA under contract ANR-11-LABX-0005-01, and CPER CLIMIBIO project, both funded by the Hauts-de-France Regional Council and the European Regional Development Fund (ERDF). J. Lasne acknowledges support from the Labex CaPPA and CPER CLIMIBIO projects and the Hauts-de-France Regional Council for his post-doctoral fellowship.Peer Reviewe

Early detection of invasion risk by exotic plant species introduced in forest arboretum in south-eastern France. Emergence of species of the genus Hakea. Measures for management

L’acclimatation d’espèces végétales exotiques dans le sud-est de la France, en particulier depuis la 2ème moitié du XIXème siècle, a contribué à la domestication d’espèces sauvages destinées à l’horticulture ornementale, l’industrie de la parfumerie ou le paysage. Quelques espèces exotiques se sont naturalisées ; certaines sont devenues envahissantes et impactent la flore indigène à fort taux d’endémisme de cette région. La détection précoce d’espèces en cours de naturalisation et l’évaluation des risques d’invasion biologique permettent d’alerter les politiques publiques pour la mise en place d’opérations de contrôle ou d’éradication. La question est posée pour des espèces végétales ligneuses introduites à partir de 1973 dans un arboretum forestier du massif de l’Estérel. Sur 400 espèces plantées initialement, 13 se naturalisent, parmi lesquelles plusieurs espèces du genre Hakea (Proteaceae), originaires d’Australie. L’objectif de cette étude était de rassembler les données utiles à l’évaluation du risque d’invasion: traits de reproduction, banque de graines, modalités de dispersion, histoire de l’introduction. L’analyse de risque a confirmé que plusieurs espèces peuvent devenir une menace pour l’environnement si elles se naturalisent à l’extérieur de l’arboretum. Deux d’entre elles (Hakea salicifolia (Vent.) B.L. Burtt et Hakea sericea Schrad. & J.C. Wendl.) ont déjà un statut d’espèces exotiques envahissantes dans d’autres pays méditerranéens. L’étude a conduit à la réalisation d’un itinéraire technique et à la sensibilisation des opérateurs locaux pour mettre en place des actions de contrôle. La méthode pourra être appliquée à d’autres arboretums, en particulier ceux qui sont situés en région méditerranéenneThe introduction and acclimatization of exotic plant species in the South-East of France, in particular since the second half of the nineteenth century, have contributed to the domestication of wild species used in ornamental horticulture, perfume industry and landscape. A few species have naturalized, some have become invasive and are impacting the highly endemic indigenous flora. Early detection of naturalizing species and evaluation of biological invasion risk are useful for control or eradication operations. The question arises for woody plant species introduced since 1973 in a forest arboretum of the Esterel Mountains. Out of 400 species planted initially, 13 are naturalizing, among which several species of Hakea genus (Proteaceae) native of Australia. This study aims to assemble useful data for the invasion risk evaluation. These data include reproduction traits, seed bank, dispersion system and introduction history. Risk analysis confirmed that several species can become a threat to the environment if they naturalize outside the arboretum. Two of them (Hakea salicifolia (Vent.) B.L. Burtt and Hakea sericea Schrad. & J.C. Wendl.) already have an invasive status in other Mediterranean countries. Studies lead to the production of a technical itinerary and to the local operators’ awareness to organize control. This method could be applied to other arboretums, especially those situated in the Mediterranean region

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

The GenTree Platform: growth traits and tree-level environmental data in 12 European forest tree species

Background: Progress in the field of evolutionary forest ecology has been hampered by the huge challenge of phenotyping trees across their ranges in their natural environments, and the limitation in high-resolution environmental information. Findings: The GenTree Platform contains phenotypic and environmental data from 4,959 trees from 12 ecologically and economically important European forest tree species: Abies alba Mill. (silver fir), Betula pendula Roth. (silver birch), Fagus sylvatica L. (European beech), Picea abies (L.) H. Karst (Norway spruce), Pinus cembra L. (Swiss stone pine), Pinus halepensis Mill. (Aleppo pine), Pinus nigra Arnold (European black pine), Pinus pinaster Aiton (maritime pine), Pinus sylvestris L. (Scots pine), Populus nigra L. (European black poplar), Taxus baccata L. (English yew), and Quercus petraea (Matt.) Liebl. (sessile oak). Phenotypic (height, diameter at breast height, crown size, bark thickness, biomass, straightness, forking, branch angle, fructification), regeneration, environmental in situ measurements (soil depth, vegetation cover, competition indices), and environmental modeling data extracted by using bilinear interpolation accounting for surrounding conditions of each tree (precipitation, temperature, insolation, drought indices) were obtained from trees in 194 sites covering the species’ geographic ranges and reflecting local environmental gradients. Conclusion: The GenTree Platform is a new resource for investigating ecological and evolutionary processes in forest trees. The coherent phenotyping and environmental characterization across 12 species in their European ranges allow for a wide range of analyses from forest ecologists, conservationists, and macro-ecologists. Also, the data here presented can be linked to the GenTree Dendroecological collection, the GenTree Leaf Trait collection, and the GenTree Genomic collection presented elsewhere, which together build the largest evolutionary forest ecology data collection available

Between but not within species variation in the distribution of fitness effects

New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is therefore of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, i.e., whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterised the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence and genetic background. We find statistical support for there being variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and that evolutionarily recent events, such as demographic changes and local adaptation, have little impact

Use of the ground in the edge of the National Park of Brasília : a multitemporal analysis

The National Park of Brasilia is a unit of conservation of integral protection in urban area pressured by the strong urban swell of the brazilian federal capital. Its edge suffered throughout the years a disordered occupation, provoked for the irregular land divisions of public and private lands, invasions and construction of highways. The analysis space-time of this phenomenon can be made through the geoprocessing with the use of images of satellite of different times, classified in groups of uses, relating the society-space process of origin politics, agrarian, environment and patrimonial to the transformation phenomenon space-time of ecosystem Savanna materialize. A time that one of the purposes of an unit of conservation is to keep the biodiversity of ecosystem local, this pressure in its edge provokes the isolation of the fauna and the flora, compromising the genetic transit and the survival of some species

Method development and validation for the determination of sulfites and sulfates on the surface of mineral atmospheric samples using reverse-phase liquid chromatography

International audienc

Limonene photocatalytic oxidation at ppb levels: characterization of gas phase, and adsorbed phase intermediates

International audienc

Limonene photocatalytic oxidation at ppb levels: characterization of gas phase, and adsorbed phase intermediates

International audienc

Heterogeneous interaction of isopropanol with Gobi mineral dusts under simulated atmospheric conditions

International audienc