Origin and distribution of rare earth elements in various lichen and moss species over the last century in France

Rare earth elements (REE) are known to be powerful environmental tracers in natural biogeochemical compartments. In this study, the atmospheric deposition of REE was investigated using various lichens and mosses as well as herbarium samples from 1870 to 1998 from six major forested areas in France. The comparison between the REE distribution patterns in organisms and bedrocks showed a regional uniformity influence from dust particles originating from the bedrock and/or soil weathering that were entrapped by lichens and mosses. These lithological signatures were consistent over the last century. The REE patterns of different organism species allowed minor influence of the species to be highlighted compared to the regional lithology. This was even true where the morphological features played a role in the bioaccumulation levels, which were related to the variable efficiency in trapping atmospheric dust particles. A comparison between REE profiles in the organisms and bark indicated a lack of influence of the substrate on lichen REE content. Lichens and mosses appear to be robust passive monitors of REE atmospheric deposition over decades because the mineral data was preserved in herbarium samples despite organic degradation being shown by carbon isotopes and SEM observations. To overcome the bias of REE concentration that resulted from organic degradation, the use of a normalized method is recommended to interpret the historical samples

Comparing early twentieth century and present-day atmospheric pollution in SW France: a story of lichens

Lichens have long been known to be good indicators of air quality and atmospheric deposition. Xanthoria parietina was selected to investigate past (sourced from a herbarium) and present-day trace metal pollution in four sites from South-West France (close to Albi). Enrichment factors, relationships between elements and hierarchical classification indicated that the atmosphere was mainly impacted by coal combustion (as shown by As, Pb or Cd contamination) during the early twentieth century, whereas more recently, another mixture of pollutants (e.g. Sb, Sn, Pb and Cu) from local factories and car traffic has emerged. The Rare Earth Elements (REE) and other lithogenic elements indicated a higher dust content in the atmosphere in the early twentieth century and a specific lithological local signature. In addition to long-range atmospheric transport, local urban emissions had a strong impact on trace element contamination registered in lichens, particularly for contemporary data

Investigation of spatial and temporal metal atmospheric deposition in France through lichen and moss bioaccumulation over one century

Lichens and mosses were used as biomonitors to assess the atmospheric deposition ofmetals in forested ecosystems in various regions of France. The concentrations of 17 metals/metalloids (Al, As, Cd, Co, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Sb, Sn, Sr, Ti, V, and Zn) indicated overall lowatmospheric contamination in these forested environments, but a regionalism emerged fromlocal contributions (anthropogenic activities, as well as local lithology). Taking into account the geochemical background and comparing to Italian data, the elements from both natural and anthropogenic activities, such as Cd, Pb, or Zn, did not show any obvious anomalies. However, elements mainly originating from lithogenic dust (e.g., Al, Fe, Ti) were more prevalent in sparse forests and in the Southern regions of France, whereas samples from dense forests showed an accumulation of elements from biological recycling (Mn and Zn). The combination of enrichment factors and Pb isotope ratios between current and herbarium samples indicated the historical evolution of metal atmospheric contamination: the high contribution of coal combustion beginning 150 years ago decreased at the end of the 20th century, and the influence of car traffic during the latter observed period decreased in the last few decades. In the South of France, obvious local influences were well preserved during the last century

Antimony bioavailability: Knowledge and research perspectives for sustainable agricultures.

The increasing interest in urban agriculture highlights the crucial question of crop quality. The main objectives for environmental sustainability are a decrease in chemical inputs, a reduction in the level of pollutants, and an improvement in the soil’s biological activity. Among inorganic pollutants emitted by vehicle traffic and some industrial processes in urban areas, antimony (Sb) is observed on a global scale. While this metalloid is known to be potentially toxic, it can transfer from the soil or the atmosphere to plants, and accumulate in their edible parts. Urban agriculture is developing worldwide, and could therefore increasingly expose populations to Sb. The objective of this review was in consequences to gather and interpret actual knowledge of Sb uptake and bioaccumulation by crops, to reveal investigative fields on which to focus. While there is still no legal maximal value for Sb in plants and soils, light has to be shed on its accumulation and the factors affecting it. A relative absence of data exists about the role of soil flora and fauna in the transfer, speciation and compartmentation of Sb in vegetables. Moreover, little information exists on Sb ecotoxicity for terrestrial ecosystems. A human risk assessment has finally been reviewed, with particular focus on Sb bioaccessibility

Use of geochemical signatures, including rare earth elements, in mosses and lichens to assess spatial integration and the influence of forest environment

In order to assess the influence of local environment and spatial integration of Trace Metals (TM) by biomonitors, Al, As, Cd, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Sb, Sn, V and Zn and some rare earth element (REE) concentrations have been measured in lichens and mosses collected in three French forest sites located in three distinct mountainous areas, as well as in the local soil and bedrock, and in both bulk deposition (BD) and throughfall (TF). Similar enrichment factors (EF) were calculated using lichens and mosses and local bedrock for most elements, except for Cs, Mn, Ni, Pb, and Cu which were significantly (KW, p < 0.05) more enriched in mosses. Similar REE ratios were measured in soils, bedrock, lichens and mosses at each study sites, indicating a regional integration of atmospheric deposition by both biomonitors. Both TM signature and REE composition of mosses revealed that this biomonitor is highly influenced by throughfall composition, and reflect atmospheric deposition interaction with the forest canopy. This explained the higher enrichment measured in mosses for elements which concentration in deposition were influenced by the canopy, either due to leaching (Mn), direct uptake (Ni), or dry deposition dissolution (Pb, Cu, Cs)

Recycling coffee wastes for healthy urban agriculture: do spent coffee ground and its biochar reduce the impact of antimony on soil quality and plant growth?

Context. Environmental contaminants ubiquitous in megacities such as metals or polycyclic aromatic hydrocarbons are accumulated in soils leading ultimately to a poor quality of these soils for agriculture purpose. The economic and environmental crisis which have been modelling the 21th century awoke an awareness and a worldwide growing interest for urban organic agriculture, making the challenge of urban soil quality a priority for the next decades. Hence, coupling remediation and amendment in one-shot is a key concept for land and ecosystem restoration. Addition of organic wastes to degraded soil is a traditional, low-cost and effective approach to improve crop yield. Among the organic amendments, spent coffee ground (SCG) is the most frequent waste generated in coffee beverage production worldwide; so its revalorization is a matter of current concern (Campos-Vega et al., 2015). Direct application of fresh SCG or its charred by-product to contaminated soils and waters has evidenced intriguing outcomes that suggest these materials suitable in remediation actions or as ‘buffer’ amendments in soils receiving contaminants. Strong evidences also suggest a direct interaction between biochar and rhizospheric microorganisms such as arbuscular mycorrhizal fungi and bacteria. However, such an association is generally dependent on biochar physicochemical characteristics. Objectives. To determine whether addition of SCG and SCG-derived biochar reduce the impact of Sb on selected extracellular enzyme activities and plant performance. Accordingly, we selected several extracellular enzyme activities implied in the biogeochemical cycles of C, N and P as indicators of soil quality (Kim et al., 2014; Sanchez-Hernandez et al., 2016). Likewise, some indicators of plant fitness were determined to assess the impact of SCG and its biochar on Sb bioavailability and accumulation. Material and methods. A microcosm experiment was conducted in a greenhouse using peas (Pisum sativum L.) as the model plant. A loam agricultural soil was amended with 5% (w/w) of SCG or SCGc. Half of the pots were spiked with antimony tartrate (KSb) to reproduce Sb concentrations frequently detected in contaminated soils. Soil enzyme activities were measured and analyzed at sowing (T0mo) and harvest (T3mo). We used an ecotoxicological index of contaminant impact on organisms called “Integrated Biological Response” index (IBRv2) to compare the global response of enzymes in each treatment (Sanchez et al., 2013). Pea yield, plant growth and colonization of SCGc by microorganisms were also evaluated. Results & conclusions. Addition of fresh SCG in soil caused a slight, but statistically significant, phytotoxic effect on plant growth and pea yield (Fig.1). However, SCG-derived biochar enhanced plant performance. Both SCG and SCGc had a significant impact on soil enzymes, the activity of which was time- and treatment-dependent (Fig.2). Biochar activated extracellular enzymes implied in C- and P-cycling, coupled with an important colonization by microorganisms (Fig.3). These findings support the general idea that biochar provides a recalcitrant support for microbial development and protection from adverse environmental conditions. Moreover, SCGc reduced significantly Sb toxicity at the end of the experiment (Table 1). However, some enzymes were still affected by Sb contamination (carboxylesterase, urease, and acid phosphatase); suggesting complex interactions between Sb, SCG/SCGc and soil microbial communities, therefore making this approach difficult to generalize for recovering urban soils contaminated by Sb

Strigolactones Stimulate Arbuscular Mycorrhizal Fungi by Activating Mitochondria

The association of arbuscular mycorrhizal (AM) fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF) that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10 (−13) M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants

Transcriptome of Aphanomyces euteiches: New Oomycete Putative Pathogenicity Factors and Metabolic Pathways

Aphanomyces euteiches is an oomycete pathogen that causes seedling blight and root rot of legumes, such as alfalfa and pea. The genus Aphanomyces is phylogenically distinct from well-studied oomycetes such as Phytophthora sp., and contains species pathogenic on plants and aquatic animals. To provide the first foray into gene diversity of A. euteiches, two cDNA libraries were constructed using mRNA extracted from mycelium grown in an artificial liquid medium or in contact to plant roots. A unigene set of 7,977 sequences was obtained from 18,864 high-quality expressed sequenced tags (ESTs) and characterized for potential functions. Comparisons with oomycete proteomes revealed major differences between the gene content of A. euteiches and those of Phytophthora species, leading to the identification of biosynthetic pathways absent in Phytophthora, of new putative pathogenicity genes and of expansion of gene families encoding extracellular proteins, notably different classes of proteases. Among the genes specific of A. euteiches are members of a new family of extracellular proteins putatively involved in adhesion, containing up to four protein domains similar to fungal cellulose binding domains. Comparison of A. euteiches sequences with proteomes of fully sequenced eukaryotic pathogens, including fungi, apicomplexa and trypanosomatids, allowed the identification of A. euteiches genes with close orthologs in these microorganisms but absent in other oomycetes sequenced so far, notably transporters and non-ribosomal peptide synthetases, and suggests the presence of a defense mechanism against oxidative stress which was initially characterized in the pathogenic trypanosomatids

EXPOSER LES SAVOIRS PLURIELS DE LA MÉMOIRE SCIENTIFIQUE DE L'UNIVERSITÉ PAUL SABATIER DE TOULOUSE

International audienceL’Université Paul Sabatier (UPS) de Toulouse (France) possède des collections scientifiques (botanique, minéralogie, zoologie, physique…) qui sont d'abord des ressources pédagogiques et de recherche qui ne sont que partiellement montrées à l'occasion d'expositions temporaires. Cette communication met en avant les acteurs qui collectent, documentent, et partagent ces savoirs pluriels, mais aussi ceux qui conçoivent et mettent en oeuvre des médiations culturelles de ce patrimoine universitaire et scientifique.Em Toulouse na França, a universidade UPS possui coleções científicas (botânica, mineralogia, zoologia, física ...) que são, antes de mais nada, recursos pedagógicos e de pesquisa, apenas parcialmente mostrados por ocasião de exposições. temporário. Esta comunicação irá destacar os atores que coletam, documentam e compartilham esse conhecimento plural, mas também aqueles que projetam e implementam mediações culturais desse patrimônio universitário. e científico

Evaluation of lichen species resistance to atmospheric metal pollution by coupling diversity and bioaccumulation approaches: A new bioindication scale for French forested areas

International audienceIn order to evaluate the metal resistance or sensitivity of lichen species and improve the bioindication scales, we studied lichens collected in eight plottings in French and Swiss remote forest areas. A total of 92 corticolous species was sampled, grouped in 54 lichen genera and an alga. Various ecological variables were calculated to characterize the environmental quality – including lichen diversity, lichen abundance, and Shannon index –, as well as lichen communities. Average ecological features were estimated for each study site and each of the following variables – light, temperature, continentality, humidity, substrate pH, and eutrophication – and they corresponded to lichen communities. Based on lichen frequencies, we calculated the index of atmospheric purity (IAP) and lichen diversity value (LDV). These two bioindication indices were closely related to lichen diversity and lichen abundance, respectively, due to their calculation formula. It appeared that LDV, which measures lichen abundance, was a better indicator of metal pollution than IAP. Coupling lichen diversity and metal bioaccumulation in a canonical correspondence analysis, we evaluated the resistance/sensitivity to atmospheric metal pollution for the 43 most frequent lichen species. After validation by eliminating possible influences of acid and nitrogen pollutions, we proposed a new scale to distinguish sensitive species (such as Physconia distorta, Pertusaria coccodes, and Ramalina farinacea) from resistant species (such as Lecanactis subabietina, Pertusaria leioplaca, and Pertusaria albescens) to metal pollution, adapted to such forested environment