Mechthild Schmitt-Jansen

Rick Relyea

Ed Topp

Dr Elizabeth A Edwards

Corinne Leyval

Prof A Elizabeth

Edwards

Dr Fernanda Cassio

Stéphane Vuilleumier

Dr Mechthild Schmitt- Jansen

Dimitrios Karpouzas

Fabrice Martin-Laurent

The complexities of pollutants and ecological interactions: Lessons from freshwater ecosystems

Keywords: Bioremediation, Biodegradation, Biotransformation, Bioavailability, Metabolisation, Retroactive action, Ecological engineering Keynote conference: The role of microbial communities in pollutant fate, distribution and degradation, Ecosystem functions, Biogeochemical cycles, Functional diversity, Microbial plasticity / adaptation, Link between functions and taxonomic diversity, Metatranscriptomics, metabolomics, metaproteomics Keynote conference: How do aquatic microbes respond to emergent contaminants? Pollutants vs. other environmental parameters, Exposure (including bioavailibility), Multivariate statistical analysis, Modelisation Keynote conference: Combined chemical and non-chemical stress: towards a mechanistic understanding of stressor interactions

Vincent (Vincent et al. Abiotic, biotic (microflora and fauna) and functional parameters of derelict soils -towards a potential use of derelict soils as a ressource) Lunch Lunch Zubrod (Zubrod et al. Are fungicides a threat for heterotrophic aquatic food webs?)

Keynote Conference

How do aquatic microbes respond to emergent contaminants? F.

Ifremer

The Institut français de recherche pour l'exploitation de la mer is an oceanographic institution in France. Ifremer contributes, through studies and expert assessments, to the knowledge of the oceans and their resources, the monitoring of marine environment and the coastline and sustainable development of maritime activities.

Frontiers

Frontiers is a community-rooted, open-access academic publisher. Our grand vision is to build an Open Science platform where everybody has equal opportunity to seek, share and generate knowledge, and that empowers researchers in their daily work.

Bronze Partners

CNRS

The National Center for Scientific Research, or CNRS, is a public organization under the responsibility of the French Ministry of Education and Research. As the largest fundamental research organization in Europe, the CNRS carries out research in all fields of knowledge, through its ten institutes.

Dr. Fernanda Cássio is an Associate Professor with habilitation at the University of Minho, in Portugal. She got her PhD in Microbiology. She is the head of the Centre of Molecular and Environmental Biology, rated as Excellent by the Portuguese Foundation for Science and Technology. She has been studying the role of decomposers of organic matter in aquatic ecosystems, with particular emphasis on microbial diversity and activity, using traditional and molecular techniques. She is also interested in ecotoxicological effects of emergent (pharmaceuticals and nanomaterials) and persistent contaminants (metals and PHAs) in freshwaters, studying effects from cells, to populations and communities levels.

Dr. Mechthild Schmitt-Jansen received her PhD in Hydrobiology at the Brandenburg University of Cottbus, Germany in the Department of Freshwater Conservation studying plankton input and dynamics in lowland streams. She continued her work as a postdoctoral researcher in the Department Chemical Ecotoxicology and the Department Effect Propagation at the Helmholtz Centre for Environmental Research -UFZ in the research areas of community ecotoxicology and site-specific toxicity assessment of aquatic systems. Since 2005 she has been working as a senior scientist at the Department Bioanalytical Ecotoxicology -UFZ leading the research group aquatic stress ecology. Since 2011 she has been holding a teaching assignment at the Technical University Bergakademie Freiberg with lectures related to aquatic ecology and ecotoxicology. Dr Schmitt-Jansen`s research interests concern community responses to multiple stressors and contaminants with special focus on biofilm ecology. Her work is based on ecological concepts like stress/pollution-induced community tolerance (SICT/PICT). In order to understand the underlying processes of stress responses, she investigates molecular responses like metabolomics and links them to phenotypic observations including physiologically-based (photosynthesis) and ecologically-based parameters (dynamics of species traits, community tolerance). Model systems she is working with rang from algal cultures to periphyton communities.

Dr. Dimitrios Karpouzas studied Crop Protection in the Aristotle University of Thessaly and then he moved to UK where he was awarded an MSc in Crop Protection from the University of Reading and a PhD on the microbial degradation of pesticides by the same University in collaboration with HRI-Wellesbourne. He is currently Associate Prof. in Environmental Microbiology and Head of the Lab of Plant and Environmental Biotechnology in the Department of Biochemistry and Biotechnology, University of Thessaly. His main research focus is on the interactions of pesticides with soil microorganisms which could lead either to biodegradation of the pesticides by soil microorganisms or to toxicity effects on the soil microbial community. On the former his focus is on the metabolic pathways involved and the genes/enzymes controlling each step of the process. In recent years within the frame of a series of EU-funded projects Dr. Karpouzas focused on the development of tools and procedures for the comprehensive assessment of the toxicity of pesticides on soil microorganisms which could be the basis for a forthcoming revision of the regulatory framework regarding pesticides soil microbial toxicity assessment.

Introduction to the Round Table: Towards an international EcotoxicoMic network for an emerging discipline facing contemporary environmental threats worlwide

Dr. Jean-François GHIGLIONE, National Center for Scientific Research, Banyuls sur mer, France.

Abstract

To date studies of hydrocarbon biodegradation have focused mainly on simplified systems (e.g. pure strains, individual molecules), which are not representative of natural environments. As a result, little is known about whole microbial communities in their actual context, and the impact of environmental fluctuations on pollutant degradation and microbial community structure is insufficiently investigated. Notably, little is known as yet about degradation within the transitional zone from oxic to anoxic conditions. It is thus important to determine the behavior of microbial communities in such oscillating conditions, especially the microbial populations involved on anaerobic metabolisms such as sulfate-reducing microorganisms.

In order to decipher the mechanisms underlying microbial community organization after an oil spill, we develop experimental ecology approaches to manipulate the microbial communities. After an adaptive stage, the modification of the microbial community structure occurred, concomitant with the beginning of the degradation of hydrocarbon compounds, followed by a succession of bacterial community structures along the degradation process. Submitting sediments to different oxygenation regimes in bioreactors showed the influence of the oxygenation on hydrocarbonoclastic microbial-assemblages, which was favoured by oxygenation after a period of anoxia. Surprisingly, sulfate-reducers were not affected by oscillating conditions.

Applying different strategies of experimental ecology, our studies highlight the functional redundancy of microbial communities involved in hydrocarbons degradation. The description of the microbial communities functioning under different oxygenation regimes by omics approaches will allow to answer important ecological questions for understanding the mechanisms underpinning the bacterial communities assemblages.

Keywords: mesocosm, microbial ecology, oil biodegradation, intertidal sediments, experimental ecology, omic's approaches Isolations were carried after detachment of the biofilm from the plastic surfaces and serial dilutions on selective agar plates of mineral medium with paraffin as the only carbon source. Microbial DNA derived from the plastic surfaces, the landfill soil and an uncontaminated neighboring agricultural soil was also analyzed by Illumina sequencing of 16S rRNA amplicons.

A total of 49 strains growing on paraffin were identified: the most representative genus is Bacillus genus with 12 different species represented, followed by Pseudomonas, Lysini- bacillus, Comanomonas and Acinetobacter. Differential scanning calorimetric analysis of the plastic samples showed an additional shoulder melting peak with various enthalpies besides the main melting peak, implying the plastic exhibited different degrees of degradation. In parallel, Illumina 16S rRNA analyses showed that the different plastics hosted different microbial communities, and that the bacterial community derived from plastic sample with the highest degradation level was the most similar to that of the soil derived from contaminated landfill. Results point to an interesting correlation between the level of plastic degradation and the composition of the microbial biofilm.

Insights into uranium tolerance of Microbacterium oleivorans A9 by proteogenomic analyses

The Microbiome Stress Project: A database for identifying stressor impacts on microbial community structure across multiple environments

Abstract

Understanding the responses of microbial communities to natural and anthropogenic stressors and their interactions is vital for determining ecosystem and host health. The impact of natural stressors (e.g. pH, temperature, storm, fire) and anthropogenic stressors (e.g. synthetic chemicals, land use) on microbial community structure have been extensively studied in various ecosystems. These studies highlight that microbial community composition is extremely sensitive to environmental change but despite an immense amount of data generated, cross-study identification of sensitive and/or tolerant microorganisms has not yet been performed. Therefore, we have constructed an extensive open-source database -The Microbiome Stress Project -to investigate how all types of stressors (natural and anthropogenic) impact microbial community structure across multiple environments (soil, biofilm, water, reactor, gut, sediment). This database is built with published/unpublished microbial data sets (using high-throughput sequencing only) and we are developing a computational pipeline using the R package 'Phylofactor' to identify microbial taxa specifically sensitive or resistant to these stressors. To test the full capacity of the Microbiome Stress Project, we preliminarily set up a smaller proof of concept dataset (8 studies). Specifically, we compared the influence of copper contamination on bacterial community structure in the soil, gut, and an activated-sludge reactor. Additionally, we examined the response of soil bacterial communities to a comprehensive set of stressors (Cu, Hg, antibiotics, PAHs, drought, nanoparticles, fire). This preliminary analysis tested if the relatedness of stressors holds true for their impact on microbial community structure and aimed at identifying indicator species responding ubiquitously to stress.

Changes in bacterial communities in response to multicontamination phenomena and other anthropogenic forcing during different hydrological regimes in mediterranean watercourses.

Abstract

Mediterranean contrasted climate affects river dynamics and therefore the concentration of micropollutants encountered in freshwaters. Indeed, contaminants get concentrated in rivers watersheds during dry periods, while, at storm events, they get remobilized from soils and sediments or arrive from combined sewer overflows, leading to recurrent multipollution phenomena. Besides, microorganisms are capable of responding very rapidly to variations in the environment. In this study, we aim at understanding more particularly how aquatic bacteria attached to particles respond to changes in pollutants concentrations. To do so, a total of 60 samplings were carried out on a typically Mediterranean coastal watercourse, the Têt River, from upstream to coastal waters, in two complete drought-flood-drought hydrological cycles along 2013-2014 and 2015-2016. A high frequency monitoring at most impacted stations was also conducted during heavy rain periods, with a total of 27 samplings. Among physico-chemical parameters measurements, up to 350 contaminants have been analyzed including fecal indicators, nutrients, metals, pesticides and pharmaceuticals. A targeted metagenomics analysis with Illumina-based 16S rRNA gene sequencing was performed to study how the diversity of bacterial communities shifts with changes in contaminants concentrations. Multipollution phenomena occurring during storm events had a remarkable impact on bacterial alpha and beta diversity with an increment of the opportunistic phylum Proteobacteria among other changes. Thus, bacteria biofilms attached to suspended matter are able to quickly react to sudden changes in pollutants concentrations, being therefore potential good early signals of multipollution stress.

Interactive effects of pesticides and nutrients on microbial communities responsible of litter decomposition in streams

Abstract

Streams contamination by pesticides and nutrients, resulting from human activities, is widespread. However, the interactive effect of these two stressors on heterotrophic microbial communities and their activity of organic matter decomposition is still poorly understood. In this context, a microcosm experiment was performed to evaluate the single and interactive effects of environmental concentrations of the herbicide S-metolachlor and the fungicide tebuconazole, on the decomposition ability of leaf-associated microbial communities, in either eutrophic or mesotrophic conditions. Eight treatments were tested in triplicate to assess, in laboratory channels, the resulting effects on natural microbial communities from a pristine forested stream (Couze d'Ardes, Centre France) developing on Alnus glutinosa leaf species. Every week for 40-days, water was renewed and samplings were performed to measure Alnus leaves' decomposition rates (K day), as well as the structure (biomass and diversity) and enzymatic activities of the leaf-associated microbial communities. Results showed a stronger influence of nutrients compared to that of pesticides. Indeed, while decomposition rates, microbial biomass, fungal diversity and ligninolytic activities (laccase, phenol oxidase) were higher in eutrophic channels compared to mesotrophic ones, only a three-fold increase of laccase activity by tebuconazole was observed in eutrophic condition. Surprisingly, such activity increase was not observed in eutrophic conditions when the fungicide and the herbicide were mixed. Overall, our study shows that the effect of realistic environmental concentrations of pesticides on leaf-associated microbial communities can be negligible compared to the effect of nutrients. However, the tested tebuconazole concentration was sufficient to trigger physiological response in fungal community.

Keywords: streams, microcosms, pesticides, nutrients interaction, leaf litter, microbial communities.

Monitoring the impact of multi-stress contamination on an environmental opportunistic pathogen, Stenotrophomonas maltophilia: application to antibiotics and metals

Abstract

Stenotrophomonas maltophilia is a ubiquitous bacterial species known to be a soil and rhi- zospheric inhabitant as well as a human opportunistic pathogen. Multi-drug resistant strains are frequently found in hospitals because of its ability to acquire resistance genes through horizontal gene transfer and its possession of efflux pumps. Recent data also showed the link between antibiotic resistance and metal resistance among both clinical and environmental strains. In this study, we evaluated over a 3 month study the impact of a cocktail of antibiotics (ciprofloxacin and sulfamethoxazole) and metals (Cu and Zn) on indigenous S. maltophilia in soil using an experimental design of soil columns exposed to manure containing various concentrations of the cocktail. In parallel, the toxicant adsorption, distribution, and migration in the soil matrix were measured to interpret the observed biological response. Data showed that regardless of the concentration of the cocktail i.e. from low (1X PEC) to high (40X PEC) doses, no changes in population abundance were observed after 7 and 100 days of exposure. Genetic diversity (REP-profile) analysis among more than 650 isolates showed that metals were the dominant stressors. Antibiotic resistance gene abundance (sulfonamide and quinolone) was unaltered and no resistance gene transfer was observed. Finally, no changes were observed on the phenotypic (antibiotic resistance) properties at low or high antibiotic doses. These data suggest the lack of a dose/response effect as well as the lack of synergic effects between metals and antibiotics on the genotypic and phenotypic evolution of S. maltophilia populations.

Biofilm phosphorus uptake capacity responds to chemical and environmental stressors in river ecosystems.

Lorenzo Proia * 1 , Anna Maria Romaní 2 , and Sergi Sabater

Abstract

Biofilms are a key component in the nutrient removal from the water column. However, nutrient uptake by biofilms may be hampered by the occurrence of pollutants or other stressors. We investigated the responses of biofilm phosphorus uptake capacity (PUC) to different chemical and environmental stressors by using chamber experiments. PUC was calculated by measuring P temporal decay after performing controlled P-spikes in chambers with biofilmcolonized tiles. Four different experiments were conducted to evaluate the response of PUC to: (a) several river waters from increasing polluted sites; (b) the effect of the bactericide triclosan (TCS); (c) the combined effect of TCS and grazers; and (d) the effect of TCS after a drought episode that affected the biofilms. These experiments showed that biofilms decreased their PUC along the pollution gradient. The biofilm PUC was significantly reduced after receiving higher TCS concentrations, though lower TCS concentrations also affected the biofilm when this was submitted to grazing pressure. PUC decrease was induced by flow interruption which further enhanced the TCS negative effects. Overall, PUC was sensitive to the effects of pollutants like TCS as well as to the action of biological (grazing) and environmental (drought) factors. The study also showed that multiple stressors enhance the negative effects of pollutants on the PUC of biofilms. Our study values the use of biofilms' PUC as a sensitive ecological-based tool to assess the effects of chemicals on freshwater communities and their derived functioning in river ecosystems.

Spatio-temporal dynamics of TPMT-harboring bacteria among urban deposits reveal significant shifts in Pseudomonas and Aeromonas populations matching pollutant concentrations

Abstract

Urban activities can generate surface deposits made, among others, of urban soils, fecal matter, and pyrogenic contaminants. These deposits harbor specific microbiota indicative of their origin and ecotoxicity. Here, the bacteriome of these deposits was investigated by an analysis of their TPMT harboring bacteria. The TPMT (thiopurine methyltransferase) can detoxify several toxic metalloid derivatives. It was found to have a distribution limited to 120 bacterial genera including major pathogens such as Pseudomonas aeruginosa, Legionella pneumophila, and Vibrio cholerae. A tpm (encoding TPMTs) meta-taxogenomics approach was developed and used to investigate shifts in TPMT-bacterial populations. Deposits were sampled over a 6 year-period from a detention basin. They had been washed off during rainfall events occurring over an industrial urban watershed in Lyon. The tpm genetic structures were compared between sampling years, and related to measured PAH and MTE concentrations. An important diversity of TPMT bacteria was observed (over 88 species). Bacterial structures were found impacted by the accumulation time-periods, with higher numbers of reads for opportunistic pathogens (e.g. P. stutzeri, P. mendocina, Aeromonas caviae, A. hydrophila) among recently trapped sediments. Reads of the phy- topathogen P. syringae were enriched in old sediments, where significant plant developments had occurred. P. aeruginosa reads were found but were not enriched over the study period. TPMT bacterial structures were correlated to pollutant concentrations (e.g. fluorene, dibenzo(a,h)anthracene and indeno(1,2,3-cd)pyrene). The tpm meta-taxogenomics approach was found highly reliable to infer the incidence of pollutants on urban bacteriomes but also for performing a tracking of pathogenic bacterial species.

Ecotoxicological effects on the interactions of fullerenes and organic micro-contaminants in stream biofilms

Anna Freixa * †1 , Vicenç Acuña 1 , Marina Gutierrez 1 , Ferran Romero 1 , Josep Sanchís 2 , Lucia-Helena Santos 1 , Sara Rodriguez-Mozaz 1 , Damià Barceló

Abstract

An increased amount of carbon nanomaterials such as fullerenes (C60) is recently observed in rivers, which co-occur with multiple organic micro-contaminants, becoming a problem of unknown consequences for aquatic systems. Due to their high surface area, C60 make good compounds for the adsorption of organic micro-contaminants, their interaction potentially affecting the toxicity for stream biofilms. We designed several experiments with the main objective of defining the toxicity of fullerenes in the presence of 3 different organic microcontaminants in biofilms. We performed 3 different experiments with epilithic biofilm exposed to environmental relevant concentrations of C60 (1ppb), one micro-contaminant (triclosan; 10 ppb diuron 10 ppb or venlafaxine 100 ppb) and a mixture of each compound (C60 + micro-contaminant) during 72 h. Nutrients, micro-contaminants and C60 concentrations were analysed in water. Functional (extracellular enzyme activities, photosynthetic efficiency and respiration) and structural endpoints (extracellular polymeric substances (EPS) and chlorophyll-a content) were analysed in biofilm. Finally, quantitative RT-PCR was used for absolute quantification of 4 different genes (16S rRNA, 18S rRNA, psaA and psbA).

Our results showed a significant decrease on algal biomass fluorescence (F0) after the exposure of C60, but no significant responses in all other endpoints. The exposure of diuron and triclosan significant altered the photosynthetic efficiency, respiration and the EPS content in biofilms whereas no evidences were detected after the exposure of venlafaxine compound. Finally, when nanomaterials and contaminants were exposed together an antagonistic response (i.e. decrease) was produced to the toxicity of the micro-pollutants in biofilms after the interaction with fullerenes.

Tolerance of stream biofilms to micropollutants indicates causality and reflects community recovery

Ahmed Tlili * †1 , Natàlia Corcoll 2 , åsa Arrhenius 2 , Thomas Backhaus 2 , Juliane Hollender 1 , Bettina Wagner 1 , and Renata Behra 1

1 Swiss Federal Institute of Aquatic Science and Technology -EAWAG (SWITZERLAND) -Switzerland 2 Dept. Biological and Environmental Sciences, University of Gothenburg -Sweden

Abstract

In Switzerland, wastewater treatment plants (WWTPs) are currently upgraded to reduce input of micropollutants into the receiving streams. This, offers the opportunity to study in real environments consequences of a reduction in micropollutants. Therefore, this study aims to examine tolerance to micropollutant mixtures of periphyton that has been sampled one year before and after the upgrade, in comparison to impacts on periphyton from non upgraded WWTPs. Results showed that one year after the upgrade, difference in micropollutant concentrations between up-and downstream of the effluent decreased. These results concurred with the tolerance measurements at this site, since no difference between up-and downstream periphyton was observed, unlike before the upgrade. Increased tolerance to the extracts, on the other hand, was detected at the non-upgraded sites in both sampling times. These results point to the strong relationship between microbial tolerance and the intensity of contamination by micropollutants. Furthermore, microbial diversity was consistent with tolerance measurements. This was the case at the non-upgraded sites in both sampling times, where bacterial and algal diversity of up-and downstream periphyton were different. On the contrary, differences at the upgraded site were less pronounced after than before the upgrade, indicating that micropollutants were a driver for the microbial diversity downstream of the WWTPs. Overall, our findings prove the relevance of using community tolerance for retrospective risk assessment of micropollutants, and to assess ecosystem recovery, while capturing the biological and chemical complexity in the environment.

Unrecognized soil algal and cyanobacterial communities as a model, for herbicide risk assessment in agricultural soils.

Cultural approaches are still helpful to isolate edaphic species for further ecotoxicological tests at the individual level. Photosynthetic pigments can provide biomass (chlorophyll a) or structural (pigment diversity) indicators. Based on chlorophyll a biomass, a modified pollution-induced community tolerance (PICT) approach was developed. Several genetic markers were successfully applied, to estimate their community composition and diversity. Toxic effects on algal and cyanobacterial biomasses and diversities have been evidenced at doses sometimes below recommended field rates, in microcosm experiment. Overall, edaphic algal and cyanobacterial communities showed a higher sensitivity to herbicides, compared to commonly studied soil bacterial and fungal community, in field monitoring. The PICT approach highlighted a higher tolerance to phenyl urea herbicides of the photosynthetic microbial communities in conventional versus organic soils. Characterization of the diversity of the algal and cyanobacterial communities, unravel links between some taxa and shift in tolerance levels. The structural stability of soil surface aggregates, considered as a functional output of algae and cyanobacteria crusts, were disturbed by herbicide treatments.

Towards the implementation of Pollution Induced Community Tolerance (PICT) approaches in water regulatory frameworks: Developing standard procedures for the sediment compartment

Abstract

Assessing the ecological effects of pollutants is an important aspect of regulations dealing with the sustainable management of water resources. In this context, scientists and regulators face the challenge of going beyond the estimation of pollutant concentrations to take into account the ecotoxicological effects on exposed aquatic communities. Among microbial ecotoxicological approaches, the pollution induced community tolerance (PICT) concept has been proven to be a suitable biomonitoring tool for in situ assessmentof either the response of aquatic microbial communities to toxicant exposure [1] or of their recovery following the improvement of water chemical quality [2,3]. The PICT is a powerful microbial metric to better link the assessment of ecological and chemical status of ecosystems by providing causal analysis in effect-based monitoring of impacted field sites [4]. However, prior its implementation in regulatory frameworks, further work is required to standardize PICT measurement and define baseline tolerance levels at large geographical scales. In this context, we will present the first results of the application of PICT approaches in the sediment compartment (with copper as model compound). We will specifically focus on both the development of standardized protocols (from sampling to dose-response modeling) and on the evaluation and control of potential confounding factors to make measurements comparable in space and time by considering robust reference conditions.

Abstract

As effect of human activities, persistent organic pollutants are discharged in the environment and can be found in surface waters. They could ultimately accumulate in wastewaters treatment plants (WWTPs) which unfortunately are rarely design to face this problem. The aim of this study was to evaluate the quality of waters in Tuscany region, in term of pharmaceutical active compounds (PhAC) concentration and environmental risk assessment. Three WWTPs managed by Publiacqua SpA located in Pistoia, Figline Valdarno and Lastra a Signa were taken into consideration. The process efficiency was studied, evaluating also the effect of seasonal variability: samples were collected from both the influents and the effluents in spring, summer and winter. The chemical characterization revealed the presence of nine PhAC including three non-steroidal anti-inflammatory drugs (diclofenac, ketoprofen, paracetamol), three antibiotics (amoxicillin, clarithromycin, doxycycline), one β-blocker (atenolol), one antiepileptic drug (carbamazepine) and one hormone (β-estradiol). As expected, their concentration was strongly affected by the season, with high antibiotics concentration detected during cold periods. As regards the wastewaters ecotoxicity, several bioassays were performed based on three seeds (watercress, sorghum and cucumber), algae, crustaceous and luminescent bacteria. Raphidocelis subcapitata was often the most sensitive organism, but data confirmed the importance of a battery of tests with model organisms representative of different trophic levels of the aquatic ecosystem. The WWTPs did not always reduce the toxicity indicating that the waters discharged in the receiving basin still had relevant effects on the ecosystem. Ecotoxicologycal index will be performed to better define the actual environmental risk.

Changes in the interactions between periphytic microalgae and micromeiofauna induced by environmental exposure to diuron and/or imidacloprid Julie Neury-Ormanni * 1 , Jacky Vedrenne 1 , Gwilherm Jan 1 , Betty Chaumet 1 , Mélissa Eon 1 , and Soizic Morin †1

1 Irstea-Bordeaux -Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture -50 Avenue de Verdun 33612 Gazinet Cestas, France

Abstract

Only a little part of agricultural pesticides reach their target organisms; the remaining is transferred by phenomena like leaching to aquatic ecosystems, where they are found in mixtures. Chemical stressors induce direct and indirect changes on the fauna and/or the flora, thus complicating pesticide risk assessment. We exposed mature biofilms for 14 days in aquaria to four treatments: control, the herbicide diuron (priority substance in the Water Framework Directive) and the insecticide imidacloprid (included in the Watchlist), singly and in mixture, at environmental concentrations (5µg/L). Our aim was to understand biofilm community responses when exposed to pesticides, based on changes in structure (species composition, diversity and density) and community tolerance, within a PICT (Pollution-Induced Community Tolerance) framework. We quantified weekly microalgal and micromeiofaunal composition, biofilm dry weight, chlorophyll a concentration and exopolysaccharide content.

In the controls, biofilm dry weight increased over time; whereas in the three pesticide treatments the biomass did not increase after 7 days of exposure. PICT approaches based on photosynthesis inhibition revealed pre-exposure to diuron, while imidacloprid didn't affect directly the microalgae. Contrastingly, the autotrophy index increased with imidacloprid pressure, in agreement with its known target action on animals. These impacts were confirmed by taxonomy analyses. The binary mixture had the same effects on microalgae as diuron, decreasing photosynthetic efficiency and chlorophyll concentration. Altogether the results of this study highlighted changes in the proportions of microalgae and micromeiofauna reflecting their interactions and exposure history. They also demonstrate that micromeiofauna should not be overlooked in microbial ecotoxicology.

RECOTOX: a network of research sites to implement multiple and multi-scale approaches for a posteriori environmental risk assessment in agricultural systems

Abstract

One of the greatest current challenges is the ever increasing environmental pollution with its concomitant environmental and human impacts. For many years, the national scientific community has pointed out the lack of long-term field and large-scale monitoring of the effects of chemicals on natural media such as water, soil and air. In that context, the network RECOTOX aims at promoting transversal, spatially explicit and integrated research to meet the scientific challenges of understanding and anticipating the environmental and health impacts of pesticides and biocides (organics, biopesticides, metals). RECOTOX includes 15 sites in metropolitan France and French West Indies, which are mostly already endorsed by national organizations (AllEnvi, INRA, CNRS, IRSTEA, universities) and instrumented networks (SOERE RBV, network of catchment area; SOERE RZA, network of long term ecological research observatories; long-term cropping system trials...). These sites allow in natura observation and experimentation in ecotoxicology in offering various and complementary agro-pedo-climatic situations. The network aims at: promoting transversal and integrated research, analyzing the whole chain "pressures-exposures-impacts" of pesticides, sharing between its sites a common culture of ecotoxicology. RECOTOX encourages the implementation of multiple and large geographical scale approaches for a posteriori environmental risk assessment in agricultural systems. Through its scientific project and its transverse activities, it will contribute to promote the use of bio-indicators as, microorganisms, for environmental risk assessment by ensuring the validity of biological tools and their operational potential. https://www6.inra.fr/ecotox/Animation-nationale/Infrastructures/RECOTOX Keywords: network, sites, in natura, pesticides, ecotoxicology, pressures, fate, exposure, effects, risk assessment, microbial communities, invertebrates, vertebrates, spatial and temporal scales, landscape

Mixtures effect of antibiotics on soil nitrification and denitrification -an experimental and modelling approach

Viviane David 1,2 , Celine Roose-Amsaleg 2 , Fabrice Alliot

Abstract

Impacts of antibiotic mixtures on microbial ecosystem functions need to be unraveled to improve the environmental risk assessment. This study aims to characterize and predict the toxicity of antibiotic mixtures on soil nitrification and denitrification processes. Different antibiotics (tetracycline, sulfonamide, macrolide, fluoroquinolone) with distinct mechanisms of action, were tested alone and in mixtures by dose-response approaches on soil substrate-induced nitrification (SIN) and minimum inhibitory concentration of soil denitrifier enrichment (MIC-E). Abundance of ammonia-oxidizers (archeal and bacterial) and denitrifiers (clade I and II of N2O-reducers) were investigated by molecular approach. For nitrification, the experimental results for different antibiotic mixture ratio were further analyzed regarding mathematical modeling interpretation based on the concepts of concentration addition (CA) or independent action (IA).

The SIN bioassay highlighted bacteriostatic effects at sulfonamide or macrolides concentrations lower than observed environmental concentrations. The differences in toxicities of antibiotics individually tested were explained by the sorption coefficient of the various antibiotics. Surprisingly, despite different cellular targets of the tested antibiotics, modelling mixture analyses revealed few differences in toxicity prediction between IA or CA concepts. Denitrification showed a higher tolerance than nitrification to the antibiotics and the lowest MIC-E for tetracycline. For nitrification and denitrification, the mixture toxicity was mainly driven by the more toxic compound. The archeal/bacterial nitrifiers ratio was positively related to the magnitude of nitrification inhibition; archaea showing invariant abundances while the antibiotic doses increased. The abundances of the denitrifier nosZ clade II greatly decreased under any antibiotic exposures unlike the nosZ clade I guilds.

Impact of pesticides on denitrification in groundwaters

Caroline Michel * 1 , Nicole Baran 1 , Laurent Andre 1 , and Catherine Joulian 1

1 BRGM -Bureau de Recherches Géologiques et Minières (BRGM) -3 avenue Claude Guillemin, B.P.

36009, Orléans cedex 2, France

Abstract Denitrification processes are involved in the decrease of nitrate (NO3-) concentrations in groundwaters impacted by human activities. Non-target/side effects of pesticides on soil microbial denitrification have been demonstrated. It is however now well established that groundwater is an ecosystem in itself with specific microbial communities different from soils' ones. If the impact of pesticides on groundwater bacterial communities has already been studed, the impact of pesticides on the denitrification activity in groundwater has still to be investigated. Groundwater samples are collected from several wells on a catchment submitted to agricultural practices with fertilizers and pesticides uses. Groundwaters contain nitrate (lower than limit of quantification up to 80 mg/l), pesticides and some of their metabolites in low concentrations. The abundance of genes involved in denitrification (narG, napA, nirS ) shows the occurrence of bacteria able to perform, at least, the two first steps of denitrification. Three groundwaters distributed within the catchment and exhibiting different denitrification signatures based on genes identification and physic-chemical properties are selected. They are used in laboratory to perform batch experiments in conditions boosting microbial denitrification (addition of KNO3 and acetate, anaerobic conditions, 25•C). The microbial ecotoxicology study is conducted in the presence or absence of pesticides spiked as single or cocktail pesticides. Several parameters (pH, concentrations of acetate, NO3, NO2, N2O, biomass) are recorded over time to quantify denitrification rate according to experimental conditions. This experimental work constitutes a first step in the understanding of the inhibitor/catalyzer role of pesticides on denitrification process.

Environmental persistence of pharmaceutical residues from hospital and urban effluents and their impacts on environmental aquatic microbial communities. de Corzent, 74200 Thonon-les-Bains, France

Abstract

Pharmaceutical residues coming from wastewater treatment plant (WWTP) discharges are regularly observed in natural waters. In this respect, the one-health issues associated with this contamination are currently being examined with considerable attention. The lack of knowledge and tools to monitor environmental exposure make their risk assessments hard to perform. The French SIPIBEL pilot site, monitored from 2011, includes a WWTP where urban and hospital wastewaters are treated separately. Treated effluents are delivered into a connected river. On this unique pilot site, the reliability of natural aquatic biofilms for monitoring the ecological impact of pharmaceuticals was investigated. The relations between field parameters, pharmaceutical concentrations, and organization of microbial communities were investigated. Microbiological and chemical tools were used to i) monitor the exposure of aquatic biofilms to pharmaceutical residues (analysis of different matrices: water, passive samplers, biofilms), and ii) assess changes in biofilm communities related to pharmaceuticals (community structure assessed through molecular fingerprinting or High Throughput Sequencing -HTS). Aquatic biofilms were grown from urban and hospital treated wastewaters, and from river surface waters located up-and downstream the WWTP discharge area. The finer the evaluation tools used to investigate the biofilm exposure and changes, the more reliable were the relations observed between pharmaceutical concentrations and community genetic patterns. Thus, the impact of low-level pharmaceutical concentrations could be investigated in situ. The combination of these monitoring tools highlighted environmental changes among the investigated aquatic ecosystem that might have impacted its functioning and ecological quality status.

Shifts in planktonic and biofilm prokaryotic community composition along a chemical multicontamination gradient in a north-western coastal mediterranean environment (Toulon bay, France) On the one hand, samples collected at the most contaminated sites exhibited a significantly higher planktonic prokaryote abundance than those from less contaminated sites, while no difference was observed in biofilms. On the other hand, alpha diversity (richness, Shannon and Chao1) was the lowest at the most contaminated sites. Moreover, microbial assemblages appeared to differ strongly all along the contamination gradient (45 to 57% dissimilarity, unweighted Unifrac distances). The main taxonomic groups identified in contaminated sites were Bacteroidetes (Flavobacteriia) and Proteobacteria (Alpha-and Gammaproteobacteria) while in the less contaminated site Proteobacteria (Alphaproteobacteria) and Cyanobacteria (Synechococcophycideae) were found dominant. Respective contributions of natural and anthropic environmental gradients to biological spatio-temporal shifts remain to be precise.

Coclet
Combination of high-throughput sequencing and geochemistry methods for evaluating the impact of single and multi-metal pollutions in soil at the aggregate scale. In soils toxic effects of metals, especially in mixtures, disturb and modify competitive balance between species of microorganisms, involving in return a deterioration of the fundamental biogeochemical cycles (C, N, P...). The sensitivity of microorganisms responses to environmental stresses make them relevant ecotoxicological indicators. Soils are spatially heterogeneous environments structured in aggregates of different sizes. Similarly to microorganisms, metals present heterogeneous and specific distribution patterns among these micro-aggregates. The objective of this work was to study the restructuring action of a copper, chromium and cadmium mixture on the microbial communities of a structured-soil at the microaggregatescale. A grassland-soil contaminated with equitoxic-concentrations of Cu-Cd-Cr, alone or mixed. The contaminated soils were gently physically fractionated during a 2 months period. Each soil size-fraction (> 250µm, 250-63µm, 63-20µm and < 20µm) and the bulk soil were analyzed for mass-balance, determination of free-soluble-total metals contents and intrinsic properties (pH-Eh and OC-N contents). Microbial communities were characterized by estimating biomass and bacterial density/diversity were estimated by 16SrDNA rtPCR and high-throughput sequencing (MiSeq-Illumina). The results provide better understanding of the spatial impact of heavy-metal mixtures on soil microbial-communities, according to their respective distribution within the different soil-microhabitats, and the temporal evolution of microbial communities. A new vision of the microstructure of soil bacterial community is presented, which also opens the way for the detection and identification of rare-taxa that may be new bio-indicators of soil health Keywords: Metals, mixtures, soil, spatialized impact, aggregates, microhabitats, microbial community, MiSeq, distribution

Abstract

Monitoring the presence of xenobiotics in ecosystems is an important environmental, health and economic challenge. Development of alternative analytical methodologies based on "omics" technologies makes possible to consider an exposure biomarker approach to xenobiotics. It is therefore no longer a matter of quantifying residues of phytosanitary products, but of measuring the level of exposure of sentinel organisms in various compartments of the environment. The stress tolerance of tissue and/or cell involves response processes whose metabolic signatures are highly volatile metabolites. The objective of this work was to evaluate the feasibility of a novel rapid approach based on a non-targeted analysis of volatile compounds in microorganisms to detect previous exposure to different types of xenobiotic. We seek to detect metabolic fingerprints specifically indicative of an exposure to metabolic response libraries obtained under treated versus control conditions of contamination.

Our analytical process is based on the in situ concentration of such volatile molecules using solid phase micro-extraction techniques (SPME) and gas chromatography coupled to a mass spectrometer (GC-MS). We highlight that low-dose exposure (NOEC) of two pyrethro 'ids (deltamethrin and cypermethrin) and a tricetone (sulcotrione) in soil and water sentinel micro-organisms (Bacillus megaterium, Pseudomonas fluorescens and the ciliate Paramecium) induces specific metabolomic fingerprints, indicative of the exposure. The toxicogenomics objective is now to feed a database of metabolic biomarkers revealing exposure to phytosanitary agents in micro-organisms then in animal models, consequent of a continuum in food production (e.g. bees, fish and poultry).

Abstract

Environmental microbial communities are key players in the transformation and mineralization of hydrocarbon pollutants. The aim of this study was to assess changes in bacterial abundance and diversity during the degradation of Tunisian Zarzatine oil by four indigenous bacterial consortia isolated from different polluted environmental matrix (a petroleum station soil, refinery reservoir soil, harbor sediment and harbor seawater). The microcosms were inoculated for two months with either a defined bacterial consortium and Zarzatine crude oil as only carbon and energy source. The microbial community dynamics was evaluated weekly in microcosms using Illumina 16S rRNA gene sequencing. An average of 7020 sequences per samples were obtained, the measured coverage was higher than 97% and more than 60% of sequence were correctly classified at species level. Degrading consortia enriched from soil and sediments were dominated by species belonging to Pseudomonas and Acinetobacter genera, while in the seawater-derived consortia Dietzia, Fusobacterium and Dicoplana emerged as dominant genera. We identified specific OTUs whose relative abundances bloomed from small to high percentages and were significantly correlated to total petroleum degradation: an OTU classified as Dietzia daqingensis in the seawater microcosms, and three OTUs classified as Acinetobacter venetianus in all two soils and sediment derived microcosms. Interestingly, a comparative analysis showed that this was the same OTU in all 3 microcosms which were derived from consortia isolated from different types (soil or sediment) and location. The work provides detailed insights about the modulation of bacterial communities involved in petroleum biodegradation. Abstract LIFE-BIOREST (www.lifebiorest.com) is a EU-project aimed at the remediation of a soil polluted by PHAs, BTEX and alkanes through the application of selected consortia of fungi and bacteria. In the first phase of the project, we have isolated from the polluted soil about 220 fungal and 140 bacterial strains with degrading abilities. Most of the fungal strains belonged to Ascomycetes (mainly Aspergillus, Cladosporium, Fusarium and Scedosporium genera) even though about 20 Basidiomycetes were also isolated. Regarding bacteria, the most abundant genus was Pseudomonas followed by Achromobacter, Stenotrophomonas and Ochrobactrum.

The isolates were obtained by means of a liquid enrichment approach on target contaminants (naphthalene, pyrene, phenanthrene, benzene, alkanes and oil extracted from the soil): the enrichment lasted 3 weeks, and sub-culturing was carried out once a week. Since the pollution in the test soil involved several meters of depth, enrichments were carried out separately using as inoculum homogenized soil samples from the 0-1, the 1-2 and 2-3 m depth. A total of 18 enrichment consortia were produced (6 target contaminants X 3 soil depths) for bacteria and other 18 for fungi, and sampled at day 0, 7, 14 and 21, giving a total of 144 samples. For each of these samples, DNA was extracted, amplified respectively for bacterial (16S) and fungal (ITS) biomarkers, and the resulting amplicons sequenced in Illumina. Results will be presented with the aim of assessing the ecological evolution of the microbial communities (bacteria and fungi) during the selective enrichment procedure in presence of different pollutants.

The dynamic degradation of pollutants by Nocardia in the infiltration basins

Abstract

Infiltration basins concentrate pollutants derived from petroleum of the anthropised catchment basin. Some bacteria degrade these pollutants to grow in these extreme environments, especially actinobacteria, whose Nocardia genus belongs to. Some species of this ubiquitous bacteria are pathogen for frail populations and cause nocardiosis, which would affect about a million people each year in the world. To date, the degradation ability of a given Nocardia species for a pollutant in particular re- mains unknown. The aim of this work is to assess which pollutants that most stimulate the growth of Nocardia pathogen species. This will lead to better understand the relationship between pollutants and infectious risk due to pathogenic Nocardia species.

We hypothesize that i) non pathogen species better degrade pollutants than pathogenic ones and ii) environmental strains of pathogenic species better degrade pollutants than clinical ones of the same species. All the environmental and clinical species are able to use pyrene, fluoranthene and nonylphenol as sole carbon source and diuron as sole nitrogen source. These pollutants are degraded in other metabolism byproducts with enhance development of other environmental bacterial species. Bacteria of nonpathogenic species are most abundant in the sediments, which lower the dissemination risk of the pathogenic ones, and impact human health.

Bacterial fungal interactions and their role for the degradation of contaminants

Lukas Yvo Wick * 1

1 Helmholtz Centre for Environmental Research -UFZ (GERMANY) (UFZ) -Permoserstrasse 15 D-04318 Leipzig, Germany

Abstract

Fungal bacterial interactions (FBI) are highly diverse and contribute to many ecosystem processes. Their emergence in structurally heterogeneous soil structures or in environmental stress scenarios still remains mainly elusive. Here we exemplify FBI by the ecosystem function of contaminant biodegradation in soil. The structural heterogeneity of soil results in the formation of a high variety of soil micro-environments and hotspots of microbial diversity and activity. In heterogeneous environments microbial activity can be considered as a 'logistic' problem, as effective biotransformation will evolve only if water, chemicals and nutrients are sufficiently available to actively degrading microbial communities. In order to cope with heterogeneous environments mycelial soil fungi have developed a unique networkbased growth form. Unlike bacteria, hyphae spread efficiently in the soil, penetrate air-water interfaces and cross over air-filled pores. We demonstrate the role of mycelial networks for preferential bacterial colonization of subsurface interfaces and discuss its effects on contaminant degradation. In particular, we show that mycelia (i) act as hotspots for horizontal gene transfer, (ii) shape predator-prey interactions and concomitant compound turnover, and (iii) passively and actively enable the functionality of bacterial ecosystems when stressed by low nutrient availability or at low matric potentials. Given the ubiquity and length of up to 500-1000 m g-1 dry soil of hyphae, we conclude that transport and dispersal processes by mycelia not only play a significant role for the ecosystem service of biodegradation of chemicals but also for nutrient and carbon turnover in soil, and, hence, the functional stability of soil ecosystems.

Keywords: bacterial fungal interactions, horizontal gene transfer, bioavailability, water, nutrient availability, contaminant

Mixtures effect of antibiotics on soil nitrification and denitrification -an experimental and modelling approach

Viviane David 1,2 , Celine Roose-Amsaleg 2 , Fabrice Alliot

Abstract

Impacts of antibiotic mixtures on microbial ecosystem functions need to be unraveled to improve the environmental risk assessment. This study aims to characterize and predict the toxicity of antibiotic mixtures on soil nitrification and denitrification processes. Different antibiotics (tetracycline, sulfonamide, macrolide, fluoroquinolone) with distinct mechanisms of action, were tested alone and in mixtures by dose-response approaches on soil substrate-induced nitrification (SIN) and minimum inhibitory concentration of soil denitrifier enrichment (MIC-E). Abundance of ammonia-oxidizers (archeal and bacterial) and denitrifiers (clade I and II of N2O-reducers) were investigated by molecular approach. For nitrification, the experimental results for different antibiotic mixture ratio were further analyzed regarding mathematical modeling interpretation based on the concepts of concentration addition (CA) or independent action (IA).

The SIN bioassay highlighted bacteriostatic effects at sulfonamide or macrolides concentrations lower than observed environmental concentrations. The differences in toxicities of antibiotics individually tested were explained by the sorption coefficient of the various antibiotics. Surprisingly, despite different cellular targets of the tested antibiotics, modelling mixture analyses revealed few differences in toxicity prediction between IA or CA concepts. Denitrification showed a higher tolerance than nitrification to the antibiotics and the lowest MIC-E for tetracycline. For nitrification and denitrification, the mixture toxicity was mainly driven by the more toxic compound. The archeal/bacterial nitrifiers ratio was positively related to the magnitude of nitrification inhibition; archaea showing invariant abundances while the antibiotic doses increased. The abundances of the denitrifier nosZ clade II greatly decreased under any antibiotic exposures unlike the nosZ clade I guilds. The identification of 22 gram negative bacteria resistant to amoxicillin or cefotaxime revealed that strains were assigned to: E.coli (7), K.oxytoca (3), E. cloacae (2), C. freundii (2), A. hyrophila (2), E. aerogenes (1), K. pneumoniae (1), R.ornithinolytica (1), R.terrigena (1), Moell.wisconsensis (1) and P.aeruginosa (1). The antibiogram results were : AMX (100%) , TE (31.8%), PIP (27%) , CAZ (27%) , NA(27%), FOX (22.7%), CTX (18%), ATM :(18%), CFP (13.6%), SXT (13.6%), TMP (9%), CIP (4.5%) , GM (4.5%) , C (4.5%) et IMP (0%). The antibiotic resistance profiles of these strains range from 1 to 11 antibiotics. The genotyping analysis by PCR showed the presence of the blaCTX-M in K. pneumoniae (1), the blaTEM in E.coli (4), K. pneumoniae (1), and C. freundii (1) and the blaSHV in K. pneumoniae (2).

Assessment of antibiotic resistance of bacteria isolated from Mugil cephalus of the bay of algiers

The results suggest that anthropogenic input influences the emergence and dessimination of resistant bacteria in coastal waters and in fish that live there, constituting a health and ecological risk.

Abstract

Sericin is considered as a waste from silk industry and causes pollution when discarded into the environment. Sericin is a water-soluble protein component in silk which, recently, shows various biological activities such as anti-oxidation, anti-inflammation, and anti-aging. In this study, sericin was extracted by 4 different methods including heat, acid, alkali, and urea and the anti-biofilm effects and cytotoxicity of each sericin against S treptococcus mutans bacteria residing within biofilm were investigated. S . mutans bacteria were cultivated in the presence of various concentrations of sericins to evaluate the anti-biofilm formation using cell density assay (inhibition effect before biofilm formed). On the other hand, various concentrations of sericins were added to the biofilm already formed by S . mutans bacteria and the viability of bacteria was assessed by MTT assay (disruption effects after biofilm formed). We found that the urea-extracted sericin at all concentrations (12.5-100 mg/mL) showed the highest potential anti-biofilm activity in terms of both inhibition and disruption effects, comparing to the sericins extracted by heat, acid, and alkali. The heat-extracted and acid-extracted sericin were found to reduce the biofilm formation dose-dependently while the alkali-extracted sericin did not show either inhibition or disruption effect on the bacterial biofilm. Due to strong negative charged of urea-extracted sericin, it may instabilize the bacterial cell wall, leading to membrane disintegration and finally to cell death. This new finding on the anti-biofilm activity of sericin would establish further researches on the mechanism and application of sericin as novel anti-biofilm agent.

Infection lithiasis inhibition by citrate-aluminum complex

Aissa Belouatek * †1

1 Laboratoire Structure, Elaboration et Application des Matériaux Moléculaires -Faculté des sciences exactes, Université Abdelhamid Ibn Badis, Mostaganem, 27000, Algeria

Abstract

The Struvite form during urinary infection with urea-splitting bacteria. The precipitation of the phosphates phase from artificial urine at different initial pH values was the object of our investigation. We chose the classical model for the study of phosphate crystallization without inhibitor and with it, in order to assess the inhibiting capacity of any chemical species used. Two solutions of following composition were mixed. In the absence of inhibitor, the crystallization of phosphates at pH = 6.5, led to the formation of brushite and amorphous carbonated calcium phosphates (ACCP), after 6 hours. The struvite and carbapatite are favorites at pH ≥ 7. The capacity of inhibitor was 100% starting from a concentration of mixture (0.05 mM of citrate, and 0.01 mM of the aluminum ions) at pH = 6.5. On the other hand at pH = 7, the addition of mixture concentration (1mM citrate and 0.01 mM of the ions aluminum) caused the total disappearance of struvite and the brushite. The complex citrate-aluminum acts on the growth and the aggregation of the struvite crystals with various concentrations at pH = 8. The complete disappearance of struvite is obtained starting from a concentration of the mixture (6mM ions citrates and 0.07 mm ions aluminium). In this investigation, complex citrate-aluminum proved to be good inhibitors of microorganism. Their effect increases with solution pH but they are more efficient in less acidic or neutral urine than in alkaline one.

Effect of lanthanides on soil microbial communities

Charlotte Berthelot * †1 , Asfaw Zegeye 1 , and Patrick Billard 1 1 LIEC -Université de Lorraine, CNRS : UMR7360, Université de Lorraine -France Abstract Lanthanides (Ln3+) are a group of metals potentially harmful when concentrated in soils such as in mining and industrial areas. However, due to their low bioavailability in soils, Ln3+ have long been considered as biologically inert at low concentration. Recent studies contradict this view, showing that Ln3+ may act as beneficial cofactor in plants and certain bacteria. In the present study, we investigated the promotion role of Ln3+ on soil bacterial communities. The effect of La3+ (Lanthanum -a model lanthanide) was examined in three soils exhibiting diverse physico-chemical characteristics. Soil spiking was performed to reach concentrations of 50 and 500mg/kg of La3+. Soil parameters (e.g. pH, La3+ availability), enzyme activities related to biogeochemical cycling of C, N and P and bacterial communities (abundance and diversity) were evaluated. Application of La3+ did not alter the soil pH, whereas bioavailability of La3+ was largely dependent on soil properties. Nevertheless, the presence of La3+ at low concentration (50mg/kg) significantly increased microbial respiration (from 129 % to 135% of control). Likewise, laccase and cellulase activities were stimulated by the 50 mg/kg treatment whereas β-glucosidase and leucine-amino peptidase were inhibited by 500mg/kg of soil

The impact of La3+ on carbon substrate utilization by microbial communities was studied using NPP method and Biolog R microplates. Consumption of organic acids (e.g. citrate, gluconate) or alcohols (e.g. ethanol) was promoted as a result of La3+ application. Overall, our study provides a first insight into the beneficial effect of lanthanides for bacterial metabolism in soil environments.

Importance of the sediment microbial diversity for degradation of pharmaceuticals in rivers

Claudia Coll Mora * †1 , Zhe Li 1 , Raven Bier 2 , Silke Langenheder 2 , and Anna Sobek For instance, the attenuation rate of acetaminophen differed by a factor of 40 between rivers Gr 'undlach-Germany and Fyris-Sweden [1]. Although data is limited, previous studies show biodiversity may be linked to the degradation potential of pollutants [2]. Therefore, we performed an experiment based on OECD TG308 to assess the influence of bacterial diversity on pharmaceutical degradation. Water and sediment were collected from rivers Fyris and Gr 'undlach, before and after the discharge of waste water treatment plants (WWTP). The sediments were acclimated with synthetic river water, then spiked with 11 pharmaceuticals at two concentration levels (200µg/L and 2mg/L). The compounds represent a wide range of biodegradation rates: acetaminophen, acesulfameK, caffeine, carbamazepine, diclofenac, furosemide, ibuprofen, metformin, oxazepam, tramadol and venlafaxine. The 40-day incubation was performed in the dark at 16•C and enabling an oxygen gradient in the sediment. The water phase was sampled at 10 time points while sediment samples were taken before spiking and at the end of incubation. We are measuring the pharmaceutical concentrations in all samples, and using Illumina-sequencing of bacterial 16SrRNA to analyze the active bacterial community. Subsequently, Rényi's entropy profiles will be calculated.

Our results will show whether microbial communities up-and downstream of a WWTP differ in their potential to degrade pharmaceuticals and whether differences in the composition and diversity can explain the variation in the degradation rates between sampling sites and rivers.

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Abstract

Recent interest in the environmental fate and effects of CeO2 nanomaterials (NMs) has stemmed from its expanded use for a variety of applications (fuel additives, catalytic converters, coating...). The majority of these NMs will end up in wastewater treatment plants (WWTP) where they will partition to sewage sludge during wastewater treatment, and ultimately re-enter the environment through the application of biosolids to agricultural soils. Thus, soil may serve as a primary sink for NMs accumulation in the environment, in which NMs may enter food webs or cause direct toxicity to plants, microbial communities, or other soil organisms. This project aims to study the impact of CeO2 NMs biotransformation on a soil-plant-microbe system using realistic exposure modes. Pristine CeO2-NMs were first aged in a laboratory-scale activated sludge reactor during 5 weeks. The biosolid enriched NMs was then amended to an agricultural soil at environmentally relevant concentration: 1 mg.kg-1 CeO2. Four treatments were performed: control soil, soil amended with 1 mg.kg-1 pristine CeO2-NMs, control biosolid without NMs, biosolid enriched NMs. The selected plant was canola (Brassica napus), an oil-producing plant. Bulk Ce L3-edge X-ray absorption spectroscopy was performed in the biosolid before culture in order to evaluate the NMs transformation in the reactor. After the culture, elemental concentrations and distributions were measured in the plant parts by ICP-AES, and laser ablation ICP-MS. Root and rhizosphere bacterial community structure was characterized by sequencing of 16S rRNA gene (Illumina MiSeq) in order to understand the impact of the biotransformation of CeO2-NMs on the microbiota.

Abstract

Cyanobacteria are photosynthetic prokaryotes that are able to synthetize a wild rang of secondary metabolites, with noticeable bioactivity (comprising toxicity and anti-bacterial activity) according to the ribosomal and non-ribosomal processes. Microcystis represents one of the most common cyanobacteria taxa constituting intensive blooms that arise in freshwater ecosystems worldwide. With the aim of contributing to better understand the variations in bio-actif metabolite production, which are potentially harmful to other aquatic macro-and micro-organisms, between clones of the same cyanobacterial blooms, we investigate the diversity of several Microcystis strains isolated from different freshwater bloomforming populations from various geographical area. Twenty-four strains of Microcystis from the Paris' Muséum Collection of cyanobacteria were compared by an integrated approach combining genotyping and metabolites chemotyping. These characterizations comprise analyses on morphology, Internal Transcript Spacer, microcystin synthesis gene, and global secondary metabolite contents. Metabolomics shotgun analyses by mass spectrometry reveal clear discriminant profiles between strains collected from identical or different localities. A global cluster analysis indicates that microcystin synthesis gene presence explains more of the metabolite diversity distribution, than the species or the sample localities parameters do. A global network generated from MS/MS fractionation patterns of the various metabolites detected in all strains performed with GNPS tool indicates that these Microcystis strains produce a wide set of chemically diverse metabolites, comprising only few known potent toxins or protease inhibitors, together with a large set of unknown molecules that still remain to be investigated and characterized at their structure as well as at their potential bioactivity/toxicity/antibacterial levels.

Ecotoxicological impact of leptospermone, a beta-triketone bioherbicide, on fungal community of two arable soils.

Abstract

Ecotoxicological impact of leptospermone, a beta-triketone bioherbicide, was investigated on the abundance and diversity of fungal community which supports important soil ecological functions (i.e. decomposition of organic matter and nutrients recycling) but which is less studied than bacterial community. A microcosm experiment was carried out on two arable soils (Perpignan and Saint Jean de Fos, France), differing in their physicochemical properties and in history treatment with synthetic beta-triketones. Soil microcosms were treated with 1x or 10x fold recommended dose (FRD) of leptospermone or not (control) and incubated in the dark for 45 days under controlled conditions. Leptospermone dissipation was monitored all along the experiment. Soil DNA was extracted from samples collected at 0, 4 and 45 days and used as template to quantify the abundance of fungi by qPCR targeting 18S rRNA genes and to estimate the diversity of fungal community by pyrosequencing of internal transcribed spacer (ITS) region 2 of the fungal rRNA. Within the 45 days of incubation, the leptospermone disappeared almost entirely from one of the two soils (i.e., DT50 < 10 days), while 25% remained in the other. In response to leptospermone exposure, the fungal community was significantly modified as compared to control. For both soils, shifts in the fungal diversity was observed in soil microcosms treated with 1x and/or 10x FRD. However, fungal diversity was found to be resilient when leptospermone was dissipated.

Abstract

Diuron-induced photosynthesis inhibition of freshwater biofilms and subsequent EC50s (half maximal effective concentrations) are determined using a 3-hour exposure in average. However, given the known rapid action of diuron, earlier responses can be expected. In this study, we performed different time-response experiments to confirm the short time lag for diuron to reach its cellular target, and to assess whether time-response curves (i.e. photosynthesis inhibition as a function of time, when diuron exposure is kept constant) can improve the assessment of short-time (pulse) pre-exposure to diuron.

Our results demonstrated that: i) diuron reaches its cellular target in a very short time-span ( ii) the delay required to reach a 50% photosynthesis inhibition is dependent on test exposure concentrations, and iii) that time-response curves may be useful to assess previous short time exposure.

In particular, we showed that exposure to diuron leads to maximal achievable inhibition within a minute (exposure to diuron-EC100, i.e. > 100µg.L-1) to 7:20 minutes (exposure to EC25). We were also able to demonstrate previous pulsed (3 hours) exposure to increasing concentrations of diuron (0, 5 and 50µg.L-1) using time-responses curves, providing a new, easyto-implement, method to assess short-term exposure to PSII inhibitors based on community photosynthesis.

Towards easy-handling tools to assess functional effects of contaminants on natural microbial and invertebrate sediment communities

Abstract

Sediments play a critical role in biogeochemical cycling and in the maintenance of the biodiversity. They are natural sinks for many contaminants which can accumulate over time and impact exposed communities, thereby disturbing the functioning of aquatic ecosystems. However, knowledge about the functional effects of contaminants on benthic communities is scarce and there is a need of ecosystem functioning indicators of ecotoxicological impacts. In the present microcosm study, we assessed the individual and combined effects of Cu and As (40 mg kg dw-1 each, 21 days of exposure) on the capacity of natural micro-and macroorganism communities from an uncontaminated river sediment to consume and decompose particulate organic matter using the bait lamina method (ISO 18311) as well as artificial tablets consisting of cellulose, bran flakes and active coal embedded in an agar matrix. The sediment toxicity was also evaluated using the standardized ostracod toxicity test (ISO 14371:2012). The two tested substrates (i.e. bait lamina and artificial tablets) showed similar results with low effects of As on feeding activity and organic matter breakdown whereas Cu demonstrated a strongest functional effect. When the two metals were combined, a total functional inhibition was observed, whatever the kind of substrate. The ostracod toxicity test also showed high toxicity of Cu-spiked and mixture-spiked sediments and low toxicity of As-spiked sediments. Our results highlight the relevance of artificial organic matter substrates to assess the functional effects of contaminants on sediment microbial and invertebrate communities, opening new perspectives to assess the functional integrity of contaminated sediments.

Abstract

The main objective of this study was to assess the effects of the single chemicals and mixtures of the fungicide picoxystrobin and the chemical 4-n-nonylphenol frequently occurring in sewage sludge, on soil microbial diversity in an agricultural sandy loam soil. The choice of compounds was based on their individual occurrence and effects in the environment, expected potential for co-occurrence in the field, and expected independent effect mechanisms due to differences in mode of action. Effects of the chemicals were assessed by amplicon pyrosequencing of the bacterial and fungal microbiota on soil samples at 0, 7, 28 and 70 days after chemicals treatment (DAT). The soil bacterial community was affected by chemicals treatment in a way causing a transient increase in abundance of Proteobacteria and decrease in Acidobacteria that was reduced through the 70 d incubation period back to a level comparable to the original soil sample. For the fungal community the most apparent effect was found for treatment with the fungicide picoxystrobin at 7 DAT, when Sordariomycetes were increased in abundance. The results for the picoxystrobin treatment indicated a slower or lack of recovery, with comparable adiversity levels at 7 and 70 DAT. Identification of the main differentially abundant OTUs further indicated effects on abundance of plant pathogenic fungi, and bacteria and fungi of importance for decomposition and nutrient cycling, underlining the need for in-depth studies of the effects of single chemicals and mixtures to assess the potential effects of agrochemicals on soil quality and function.

Examining the impact of plastic leachates on key marine photosynthetic bacteria

Indrani Sarker 1 , Verena Schrameyer 1 , Liam Elbourne 1 , Ian Paulsen 1 , and Sasha Tetu * †1

1 Chemistry and Biomolecular Sciences -Macquarie University, NSW, 2109, Australia

Abstract

Plastic pollution in the marine realm is an issue of growing concern; one understudied risk related to such pollution is that plastic debris can leach a variety of potentially toxic chemicals. Currently little is known regarding how plastic leachates impact marine organisms particularly primary producers such as photosynthetic marine cyanobacteria. Prochlorococcus species are significant players in oceanic primary production and global carbon cycling. Exposure to plastic leachate from common plastic debris items: plastic bags (HDPE) and plastic matting (PVC), impacted in vitro growth and primary productivity of Prochlorococcus marinus strains. The strains tested, MIT 9312 and NATL2A (model high light and low light-adapted ecotypes), showed distinct differences in their sensitivity to each leachate. Genome-wide transcriptomic analyses revealed a suite of genes were differentially expressed following leachate exposure, including many linked to primary production and stress responses. Understanding how key marine primary producers are affected by plastic leachate is critical to determining potential future impacts of plastic pollution on marine ecosystems as a whole.

Herbicide mixture of mesotrione, nicosulfuron and s-metolachlor: biotransformation pathway and toxicity.

Louis Carles 2,1 , Muriel Joly

Abstract

To reduce pesticide consumption, the new-generation molecules, currently used in agriculture, are sprayed at lower dosages but often in mixtures to increase their efficiencies. Despite the great environmental concern of unintentional mixture of pesticides coming from agricultural lands, little data is available concerning the effects of these cocktails on the fate and impact of each molecule. We focused our work on a mixture of three herbicides composed of mesotrione (β-triketone), nicosulfuron (sulfonylurea) and S-metolachlor (chloroacetanilide), commonly applied on maize crops in a short period of time. A Bacillus megaterium Mes11 strain [1], isolated from an agricultural soil, was found to be able to biotransform mesotrione and nicosulfuron, alone or in cocktail, but not S-metolachlor. Although the biodegradation pathways were not affected in the case of binary or ternary herbicide mixtures, kinetics of nicosulfuron disappearance as well as those of mesotrione and nicosulfuron metabolite formation were strongly modulated. The toxicity of the parent compounds and metabolites was evaluated for individual compounds and mixtures with the standardized Microtox R test. Synergistic interactions were evidenced for all the parent compound mixtures, while synergistic, antagonistic or additive toxicity was obtained for metabolite mixtures, depending on the mixture. The results obtained highlight the need to take into account the active ingredient and metabolites all together for the determination of environmental fate and toxicity of pesticide mixtures and thus to improve the Environmental Risk Assessment of pesticide cocktail.

Integrating functional responses of autotrophic microorganisms to chemicals in ecological risk assessment

Floriane Larras * †1 , Elise Billoir 2 , Stefan Lips 1 , and Mechthild Schmitt-Jansen 1

1 Helmholtz Centre for Environmental Research, Department Bioanalytical Ecotoxicology (UFZ) -Leipzig, Germany 2 Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC) -CNRS : UMR7360, Université de Lorraine -Metz, France Abstract Microorganisms (e.g. bacteria, fungi and algae) are implied in various ecosystem functions such as biogeochemical cycles or pollutants degradation. That means that they are crucial for ecosystem functioning, here considered as the overall performance of a system. In the environment, organisms are exposed to anthropogenic pressures which are known to potentially induce structural and functional changes. Many studies report causal links between chemicals exposure and functional responses, but little is known about the involved biochemical pathways supporting specific functions. Moreover, most of a priori ecological risk assessment (ERA) tools are based on structural endpoints and do not necessarily ensure the protection of functional endpoints. The recent raise of OMICs approaches (e.g. transcriptomics and metabolomics) opens the perspective in ecotoxicology to explore pathways involved in ecological functions. Based on OMICs approaches, we identified functional responses of microorganisms across different biological organization levels to improve linkage of pathways, responsive to chemical exposure, and ecosystem functions. Such results present a great potential for the development of an integrative ERA tool based on microorganisms functions sensitivity at different biological levels. The challenge remains how to include these data in ERA strategies. As a first step, we developed an approach based on multi-level sensitivity distributions. We exemplify a first version of this tool, using the transcriptomic and metabolomic responses of Scenedesmus vacuolatus to triclosan. As a perspective, the tool will be transposed and adapted to benthic microbial communities in order to release an integrative ERA tool considering ecological systems.

Impact of repeated treatments of the pesticides chlorpyrifos or tebuconazole on soil microorganisms using alternative methods

Abstract

Pesticides can harm non-target organisms such as soil microorganisms involved in important ecosystem functions. In the European Union, during pesticide authorization process conducted by European Food Safety Authority (EFSA), potential risks on soil microorganisms are solely evaluated by estimating its impact on mineralization of nitrogen which is a too general test to detect pesticide ecotoxicity towards microorganisms. In consequence, pesticide risk assessment conclusions on soil microorganisms edited by EFSA can differ from academic researches carried out with more advanced techniques allowing to monitor the abundance, diversity and activity of microbial community. This is the case for the insecticide chlorpyrifos (CHL) and the fungicide tebuconazole (TCZ) studied for their microbial ecotoxicological impact using new experimental design and advanced techniques. A new experimental design consisting in repeated exposure of soil microcosms to CHL or TCZ was used to evaluate (i) pesticide biodegradation, (ii) the impact on purification functions, and (iii) on the diversity of soil bacteria.

In response to repeated CHL treatments, the capability of soil microorganisms to degrade it increased. On the contrary, soil microorganisms kept a low ability to degrade TCZ. Soil purification functions were slightly (CHL) or not (TCZ) affected by pesticide treatments. However, the soil bacterial diversity changed in response to repeated exposure to both pesticides. Nitrospira (reducing effects) and Lysobacter (enhancing effects) were the two genera the most importantly modified in their abundance. This study provides new insight in the fate and ecotoxicological impact of CHL and TCZ on soil microorganisms.

Predictive assessment of the impact of biocidal substances on soil microbial respiration and nitrogen transformation

Abstract

The purpose of the Biocidal Products Regulation (BPR) is to improve the free movement of biocidal products within the Union while ensuring a high level of protection of human, animal health and the environment. The approach is based on, first the approval of the active substance (inclusion in the Union list) and afterwards the authorisation of products that contain such active substances. For the environment, the risk is mainly assessed for the aquatic and the terrestrial compartments. For each compartment, the predicted environmental concentration (PEC) is compared to the predicted no effect concentration (PNEC). The PNEC is derived from the lowest endpoint for the compartment taken into account and the appropriate assessment factor. Soil ecotoxicity endpoints can be provided for earthworms, plants and soil microorganisms. Ecotoxicity data for soil microorganisms are often coming from two OECD Tests Guidelines: Carbon (OECD 217) and Nitrogen (OECD 216) Transformation Tests.

These tests guidelines are also used for the risk assessment of the Plant Protection Products. Nevertheless, different requirements and interpretation of the results are applied for each regulation. These differences deal with the threshold of toxicity, the number of tested concentrations to derive the endpoints, the duration of the tests... These adaptations are either directly proposed in the tests guidelines, or have been included in the Guidance on the BPR (volume IV Environment, Part B). This poster presents the OECD 216 and 217 guidelines and their adaptations for the BPR. Moreover, the case of the assessment of microbial biocidal substance is discussed.

  Frontiers in Microbiology is the #2 most cited open-access journal in the category of Microbiology, and overall the #8 most cited journal in Microbiology.

  Dissipation of chloroacetanilides in agricultural soil microcosms: insights from stable isotope fractionation and bacterial community response Hydrocarbon impact on microbial communities in marine coastal sediments Robert Duran * 1 , Cyril Noel , Cristiana Cravo-Laureau , and Christine Cagnon 1 Equipe Environnement et Microbiologie -IPREM UMR CNRS 5254 (EEM) -CNRS : UMR5254, Université de Pau et des Pays de l'Adour [UPPA] -IBEAS -UFR Sciences BP 1155 64013 PAU CEDEX, France

1

  Brice Reoyo-Prats * †1 , Dominique Aubert 1 , Olivier Verneu 1,2 , and Carmen Palacios 1 Centre de Formation et de Recherche sur les Environnements Méditérranéens -CEFREM (Perpignan, France) (CEFREM) -Université de Perpignan : VIADOMITIA -UPVD (FRANCE), Centre national de la recherche scientifique -CNRS (France) -France 2 Univ. for Environmental Sciences and Management -ZA-2520, Potchefstroom, South Africa

Florent

  Rossi * †1 , Joan Artigas 1 , Clarisse Mallet 1 , Christelle Margoum 2 , Matthieu Masson 2 , and Stéphane Pesce 2 1 Microorganismes : génome et environnement (LMGE) -CNRS : UMR6023, Université d'Auvergne -Clermont-Ferrand -24, avenue des Landais BP 80026 63 170 Aubiere, France 2 Milieux aquatiques, écologie et pollutions (UR MALY) -Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture -IRSTEA -5 rue de la Doua, BP 32108, 69616 Villeurbanne cedex, France

  Armelle Crouzet * † , Géraldine Depret 1 , Justine Thiot 2 , David Lejon 2 , Alain Hartmann 1 , Lorenzo Spadini 3 , Sabine Favre-Bonté 4 , and Sylvie Nazaret 4 1 Agroécologie -Agrosup, Institut national de la recherche agronomique (INRA) : UMR1347, Université de Bourgogne -BP 86510, F-21000 Dijon, France 2 Rovaltain Research Company -Rovaltain Research Company -France 3 Institut des Géosciences de l'Environnement (IGE) -Institut de Recherche pour le Développement, Institut Polytechnique de Grenoble -Grenoble Institute of Technology, Centre National de la Recherche Scientifique, Université Grenoble Alpes -UGA -IGECS 4070038 058 Grenoble Cedex 9, France 4 Ecologie Micorbienne -Universite Claude Bernard Lyon1, CNRS : UMR5564 -Campus de la Doua 43 Bd du 11 Novembre 1918 69622 Villeurbanne, France

Stéphane

  Pesce * †1 , Anaïs Charton 1 , Aymeric Dabrin 1 , Emilie Lyautey 2 , Ayanleh Mahamoud Ahmed 2 , Emmanuel Naffrechoux 3 , Olivier Perceval 4 , and Chloé Bonnineau 1 1 UR MALY -Irstea -5 rue de la Doua, BP32108, 69616 Villeurbanne Cedex, France 2 Centre Alpin de Recherche sur les Réseaux Trophiques des Ecosystèmes Limniques (CARRTEL) -Université de Savoie, Institut national de la recherche agronomique (INRA) -Domaine Universitaire, 73376 Le Bourget-du-Lac Cedex, France 3 Laboratoire de Chimie Moléculaire et Environnement (LCME) -Université Savoie Mont Blanc, Université Grenoble Alpes -Campus Scientifique de Savoie-Technolac Le Bourget du Lac Cedex, France 4 Agence Française pour la Biodiversité -AFB, France -5 Square Félix Nadar, 94300 Vincennes, France

  [1] Tlili et al., 2017. Water Res 111; [2] Larras et al., 2016. ESPR 23; [3] Pesce et al., 2016. Agr Ecosyst Environ 221; [4] Tlili et al., 2016. Freshwater Biol 61 Evaluation of the ecotoxicologycal impact of municipal wastewaters on wildlife: a case study in Tuscany Federica Spina * 1 , Laura Palli , Mario Aragno , A Bonari , A Bossi , I Pompilio , S Dugheri , D Santianni , S Caffaz , M Vincenzi , Riccardo Gori , and Giovanna Cristina Varese 1 Mycotheca Universitatis Taurinensis, University of Turin -Turin, Italy

  2 , Marjolaine Bourdat-Deschamps 1 , and Olivier Crouzet * †1 1 UMR 1402 ECOSYS -Institut National de la Recherche Agronomique -INRA, AgroParisTech, Université Paris-Saclay -78026 Versailles cedex, France 2 Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS) -École Pratique des Hautes Études [EPHE], CNRS : UMR7619, Université Pierre et Marie Curie (UPMC) -Paris VI -UPMC, Case courrier 105, 4 place Jussieu, 75005 Paris, France

  Agnès Bouchez * †1 , Teofana Chonova , Benoit Cournoyer , Leslie Mondamert , and Jérôme Labanowski 1 INRA CARRTEL -Institut National de la Recherche Agronomique -INRA (FRANCE) -75 bis av.

  Clément * 1 , Jean-François Briand 2 , Gaël Durrieu 1 , Christophe Le Poupon 1 , Sébastien D'onofrio 1 , Lyria Berdjeb 1 , Dario Omanović 3 , Cédric Garnier 1 , and Benjamin Misson 1 1 PROTEE -Université de Toulon : EA3819 -83041 Toulon, France 2 MAPIEM -Université de Toulon : EA4323 -83041 Toulon, France 3 Ruer Bošković Institute -Bijenička 54, Zagreb, Croatia Abstract Mediterranean coastal environments are currently subjected to various anthropogenic inputs, resulting in multiple chemical contaminations. Microbial communities play an essential role in ecosystem functioning, however their response to such chemical multicontaminations remains poorly characterized. Samples were collected from June 1st to June 29th, 2015 at two depths (top and bottom of the water column) in five chemically contrasted sites along a gradient of multicontamination (in several trace metals and nutrients) in Toulon Bay. By combining flow cytometry and 16S rRNA gene sequencing (Illumina MiSeq), we assessed spatio-temporal variability of planktonic and biofilm microbial abundance and diversity in relation to natural and human-influenced environmental variables (physico-chemical variables, nutrients and trace metals (TM) concentrations). Strong spatial gradients of TM concentrations were observed in both surface and bottom seawater, with up to 115-fold enrichments.

1

  Jean Martins * 1 , Frédéric Lehembre , Emilie François , Aline Navel , Erwann Vince , and Lorenzo Spadini Institut des Géosciences de l'Environnement (IGE) -Institut National Polytechnique de Grenoble (INPG), INSU, OSUG, CNRS : UMR5001, Institut de recherche pour le développement [IRD] : UR252, Université Grenoble Alpes -IGE -HyDRIMZ -Université Grenoble Alpes CS 40 700. F-38058 Grenoble cedex 9, France Abstract J.M.F. Martins, F. Lehembre, E. François, A. Navel, E. Vince and L. Spadini. IGE UMR5001, UGA-CNRS-GINP-IRD, France

1

  Ecology of bacterial communities during petroleum biodegradation: a molecular analysis on degrading consortia isolated from hydrocarbon polluted soils, sediment and seawater samples Rahma Omrani * †1 , Edoardo Puglisi * ‡2 , Giulia Spini 2 , and Dalila Saidane 1 Laboratory of Analysis, Treatment and Valorization of Environmental Pollutants and Products, Faculty of Pharmacy, Monastir University, Tunisia -Tunisia 2 Istituto di Microbiologia, Università Cattolica del Sacro Cuore (UCSC) -Via Emilia Parmense 84, 29122 Piacenza, Italy, Italy

1

  Enrichment procedures for the isolation of xenobiotic-degrading bacterial and fungal strains: a focus on microbial ecology Giulia Spini * †1 , Federica Spina 2 , Anne-Laure Blieux 3 , Tiffanie Regnier 3 , Abdelwahad Echairi 3 , Ilaria Re 4 , Giovanna Varese 2 , and Edoardo Puglisi * ‡1 Istituto di Microbiologia, Università Cattolica del Sacro Cuore (UCSC) -Via Emilia Parmense 84, 29122 Piacenza, Italy, Italy 2 Mycotheca Universitatis Taurinensis, University of Turin, Turin, Italy -Italy 3 SATT Grand-est -Welience Agro-Environnement, Bretenière, France -Societe d'Acceleration du Transfert de Technologie (SATT) Grand Est -Welience -France 4 Consorzio Italbiotec -Italy

Florian Vautrin * 1 1

 1 Laboratoire d'Ecologie Microbienne (LEM) -Université Claude Bernard -Lyon I (UCBL) -16 rue Raphael Dubois, 69100 Villeurbanne, France

  2 , Marjolaine Bourdat-Deschamps 1 , and Olivier Crouzet * †1 1 UMR 1402 ECOSYS -Institut National de la Recherche Agronomique -INRA, AgroParisTech, Université Paris-Saclay -78026 Versailles cedex, France 2 Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS) -École Pratique des Hautes Études [EPHE], CNRS : UMR7619, Université Pierre et Marie Curie (UPMC) -Paris VI -UPMC, Case courrier 105, 4 place Jussieu, 75005 Paris, France

1

  Souhila Alouache * 1,2 , Nawal Touahir 1 , and Rabah Bakour 2 High national school of marine sciences and coastal management, LCVRM laboratory (ENSSMAL) -BP19, campus universitaire, Bois des cars, Algiers, Algeria 2 University of sciences and technology Houari boumedienne, laboratory of cellular and molecular biology (USTHB) -BP32 El Alia -Bab ezzouar, AlgeriaAbstractThe study of antibiotic resistance in aquatic organisms is important because it could indicate the extent of change in aquatic ecosystems due to anthropogenic actions. Our study focused on the bacterial flora of Mugil cephalus; a fish that frequents coastal waters and mouths ; caught in the bay of algiers between May and October 2015. The evaluation of the resistance of the total flora to antibiotics revealed high rate of resistance to amoxicillin, mean rate to cefotaxime, ceftazidime, ciprofloxacin and tetracycline and low to imipenem and gentamicin.

New1

  Finding on the Anti-biofilm Activity of Silk Sericin Against Streptococcus mutans Bacteria Residing within Biofilm Pornanong Aramwit * †1 and Nipaporn Bang 1 Bioactive Resources for Innovative Clinical Applications Research Unit and Department of Pharmacy Practice -Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand

1 1

 1 Department of Environmental Science and Analytical Chemistry, Stockholm University (ACES-SU) -Svante Arrhenius väg 8, SE-11418 Stockholm, Sweden 2 Evolutionary Biology Centre (EBC) -Evolutionary Biology Centre, EBC Norbyvägen 14-18 752 36 Uppsala, Sweden Abstract Degradation of pharmaceuticals in aquatic systems is impacted by environmental factors.

1

  [1] Li et al.2016.doi:10.1021/acs.est.5b06327 ; [2] Johnson et al.,2015.doi:10.1128/AEM.03286-14 Effect of nanoceria biotransformation in activated sludge on the microbiota associated to canola roots Blanche Collin * 1 , Mohamed Barakat 2 , Philippe Ortet 2 , Wafa Achouak 2 , Melanie Auffan 1 , Emmanuel Doelsch 3 , and Catherine Santaella 2 Centre européen de recherche et d'enseignement de géosciences de l'environnement (CEREGE) -Institut de Recherche pour le Développement : UMR D 161, AixM arseilleU niversité : U M 34, CollègedeF rance, CentreN ationaldelaRechercheScientif ique : U M R7330 --AvenueLouisP hilibert -BP 80 -13545Aix -en -P rovence, F rance 2 Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements extrêmes (LEMIRE) -CNRS : UMR7265, CEA, Aix-Marseille Université -AMU -St-Paul-lez-Durance, France 3 UPR Recyclage et risque (CIRAD) -CIRAD : UPR78 -Aix-en-Provence, Montpellier, Saint-Denis de la Réunion, France

1

  The impacts of three herbicides on the fatty acids of the freshwater diatom Gomphonema gracile Global metabolomic characterizations of Microcystis spp. highlights clonal diversity in natural bloom-forming populations and expands metabolite structural diversity Séverine Le Manach 1 , Charlotte Duval 1 , Arul Marie 1 , Cécile Bernard 1 , and Benjamin Marie * †1 Molécules de Communication et Adaptation des Microorganismes (MCAM) -Muséum National d'Histoire Naturelle (MNHN), CNRS : UMR7245, Sorbonne Universités, Sorbonne Universités -France

  Clarisse Mallet * 1 , Sana Romdhane 2 , Jérémie Beguet 3 , Fabrice Martin-Laurent 3 , Christophe Calvayrac 2 , Cédric Bertrand 4 , and Lise Barthelmebs 2 1 Microorganismes : génome et environnement (LMGE) -Université d'Auvergne -Clermont-Ferrand I, CNRS : UMR6023, Université Blaise Pascal -Clermont-Ferrand II -Université Blaise Pascal, Campus des Cézeaux, 24, avenue des Landais BP 80026 63 170 AUBIERE, France 2 Biocapteurs -Analyse-Environnement (BAE) -Université de Perignan Via Domitia -Université de Perpignan Via Domitia, 52 Av Paul Alduy, 66860 Perpignan cedex, France 3 INRA (UMR Agroécologie) -Institut national de la recherche agronomique (INRA) : UMR1347 -INRA UMR 1347 Agroécologie 17 rue sully BP 86510 21065 Dijon Cedex, France 4 CRIOBE USR3278, Université de Perpignan Via Domitia -Univ de Perpignan Via Domitia -58 Avenue Paul Alduy 66860 Perpignan Cedex, France

1

  Assessing biofilm pulse exposure to PSII inhibitors using time-response curves Soizic Morin * 1 , Betty Chaumet 1 , and Nicolas Mazzella 1 Laboratoire Ecosystèmes aquatiques et changements globaux (UR EABX) -Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture -IRSTEA -50 avenue de Verdun, 33612 Cestas cedex, France

  Stéphane Pesce * †1 , Sophie Campiche 2 , Ayanleh Mahamoud Ahmed 1,3 , Carmen Casado-Martinez 2 , Chloé Bonnineau 1 , Aymeric Dabrin 1 , Emilie Lyautey 3 , and Benoit J.d. Ferrari 2 1 UR Milieux Aquatiques, Ecologie et Pollutions (UR MALY) -Irstea -5 rue de la Doua BP 32108 F-69616 Villeurbanne Cedex, France 2 Swiss Centre for Applied Ecotoxicology (Eawag-EPFL) -EPFL-ENAC-IIE-GE, Station 2, CH-1015 Lausanne, Switzerland 3 Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL) -Institut National de la Recherche Agronomique : UMR0042, Université Savoie Mont Blanc : UMRINRA / USMB -Station d Hydrobiologie Lacustre, Le Bourget-du-Lac 73376, France

  Amplicon pyrosequencing of bacterial and fungal community structure in Norwegian agricultural sandy loam soil -assessment of chemical mixture effects and implications for soil and plant health Marianne Stenrød * 1 and Erik Lysøe 1 1 Norwegian Institute of Bioeconomy Research (NIBIO) -Høgskoleveien 7, NO-1433 Aas, Norway

  Jennifer Rocca * †1 , Joanna Blaszczak 1 , Firas Midani 1 , Marie Simonin 1 , and Alex Washburne 2 1 Duke university [Durham] -Durham, NC 27708, United States 2 Montana State University -Bozeman, Montana 59717, United States

  Ecology of Aquatic Systems -University of Bruxelles (ESA -ULB) -Belgium 2 Institute of Aquatic Ecology -University of Girona (IEA -UdG) -Spain 3 Catalan Institute for Water Research (ICRA) -Spain

	2,3
	1

  Emilie Bourgeois * 1 , Romain Marti 1 , Claire Bernardin 1 , Céline Bécouze 2 , Sébastien Ribun 1 , Laurence Marjolet 1 , Audrey Gleizal 1 , Sylvie Barraud 2 , Gislain Lipeme Kouyi 2 , Laure Wiest 2 , Didier Blaha 1 , and Benoit Cournoyer 1 1 Ecologie Microbienne -Bacterial Opportunistic Pathogens and Environment -CNRS 5557, INRA 1418, Université Lyon 1, VetAgro Sup -France 2 Laboratoire Déchets, Eaux, Environnement, Pollutions (DEEP) -INSA -Institut National des Sciences Appliquées -34 avenue des Arts Bâtiment Bât. JCA Coulomb 69621 Villeurbanne cedex, France

  1,2 , Marinel•la Farré 2 , and Sergi Sabater 1,3 1 Catalan Institute for Water Research (ICRA) -Spain 2 Institute of Environmental Assessment and Water Research (IDAEA-CSIC) -Spain

3

Institute of Aquatic Ecology -University of Girona (IEA -UdG) -Spain

  Christian Mougin * 1 , Véronique Gouy †2 , and Vincent Bretagnolle ‡3 1 Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS) -Institut National de la Recherche Agronomique : UMR1402 -Pôle Ecotoxicologie, Route de St-Cyr, 78016 Versailles, France 2 Milieux Aquatiques, Écologie et Pollutions (MAEP) -Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture -5 rue de la Doua, 69626, Villeurbanne, France 3 Centre d'Etudes Biologiques de Chizé (CEBC) -CNRS : UMR7372 -405 Route de La Canauderie, 79360, Villiers-en-Bois, France

  1,2 , Frédérique Bonnemoy 1 , Martin Leremboure 2 , Florence Donnadieu 1 , Isabelle Batisson * †1 , and Pascale Besse-Hoggan 2 2 Institut de Chimie de Clermont-Ferrand (ICCF) -CNRS : UMR6296, Université Blaise Pascal -Clermont-Ferrand II, Ecole Nationale Supérieure de Chimie de Clermont-Ferrand -24 Avenue des Landais, 63177 Aubière Cedex, France 1 Laboratoire Microorganismes : Génome et Environnement, UMR CNRS 6023 (LMGE) -Université Clermont Auvergne -France

  Veronika Storck 1 , Nadine Rouard 1 , David Bru 1 , Jeremie Beguet 1 , Lucio Botteri 2 , Ayme Spor 1 , Marion Devers 1 , and Fabrice Martin-Laurent * 1 1 Agroécologie -Institut National de la Recherche Agronomique : UMR1347 -INRA -17 rue Sully -BP 86510 -21000 Dijon, France 2 AEIFORIA srl (AEIFORIA) -Fidenza, Italy

  Anne Straczek * †1 and Béatrice Chion 1 1 French Agency for Food, Environment and Occupational Health Safety. Regulated products assessment Department, -ANSES -14 Rue Pierre et Marie Curie, 94 701 Maisons-Alfort Cedex, France

* Speaker † Corresponding author: florent.rossi@univ-bpclermont.fr sciencesconf.org:ecotoxicomic:149382

Interactive impacts of silver and phosphorus on autotrophic biofilm elemental and biochemical quality for a macroinvertebrate consumer

out to the public to mobilize citizens in favor of biodiversity. IRD providing scientific advice on the major challenges of development. The Institut de recherche pour le développement, an internationally recognised multidisciplinary organisation, is a French public research establishment operating under the joint authority of the French Ministry for Higher Education, Research and Innovation and the French Ministry for Europe and Foreign Affairs. It takes an original approach to research, expertise, training and knowledge-sharing for the benefit of countries and regions, making science and innovation key drivers in their development. research into commercial practice to develop bioremediation and bioaugmentation strategies for groundwater pollutants. She is also the founding director of BioZone, a Centre for Applied Bioscience and Bioengineering Research at the University of Toronto and a Tier 1 Canada Research Chair in Anaerobic Biotechnology. In 2016, she was awarded the Canada Council of the Arts Killam Prize in recognition of outstanding career achievements.

Abstract

The use of nanoparticles (NPs) in many common products led to assess their impact on living organisms and microorganisms in various environments. Several studies showed the deleterious effects of metal nanoparticles (NPs) on soil microbial communities and pointed out the importance of organic matter (OM) content in the ecotoxicity of NPs due to its role as dispersing and stabilizing agent . In this study, we assessed the role of plant root exudation in NPs ecotoxicity in soil to-wards the microbial communities involved in the nitrogen cycle assuming that plant root exudation reduces NPs ecotoxicity in the rhizosphere due to a higher dissolved OM content compared to bulk soil. The experimental design consisted in planted and unplanted soil microcosms contaminated or not with CuO-NPs (1mg and 100 mg/Kg) often entering in the composition of nano-fertilizers or pesticides. Control microcosms spiked with soluble Cu were included. Since the measurement of root exudation is hardly possible in soil, we compared the effect of two types of wheat (Triticum aestivum) exhibiting contrasted traits reflecting contrasted exudation. Ecotoxicological NPs effects were assessed after 30 and 50 days of incubation in a greenhouse by measuring microbial activities (nitrification and denitrification) and microbial abundances by qPCR targeting function genes in rhizosphere and bullk soil. NPs characterizations (sur-face charges and hydrodynamic diameter) were realized in solutions of rhizosphere and bulk soils. Dissolved OM was measured in both solutions. The microbial ecotoxicological effects of NPs are discussed in the light of plant traits and NPs characteristics.

Abstract

In the last decade, omics tools dedicated to microbial communities have been developed to characterize the functional groups of those communities and better understand microbial response to contamination. Most of those tools focused on heterotrophic and fungal communities while omics application dedicated to microalgae and diatoms are mostly restrained to diversity assessment (e.g. based on 18S rRNA or rbcL genes). In this study, the possibility of studying gene expression in autotrophic river biofilm communities was explored and we present the proof of concept for a Functional Gene Array (FGA), based on consensus sequences from genes of key physiological processes. Indeed, microarrays offer a comprehensive tool for system-wide analysis of community functioning based on the simultaneous detection of the activity of thousands of genes. The FGA designed in this study include 83 functional genes chosen to reflect several essential biochemical pathways and specific stress response pathways of microalgae. Probes of these genes were designed from consensus sequences from up to 6 microalgal species (diatoms and chlorophytes). Furthermore, species-specific probes were included resulting in 1554 unique oligonucleotide probes for 83 different genes. RNA extracted from Chlamydomonas reinhardtii, Scenedesmus vacuolatus and multi-species biofilms was then used to test different hybridisation conditions. Signal intensity was affected by sequence divergence but results showed that a hybridisation temperature of 55 o C allowed a good compromise between cross-hybridisation and specificity. Due to the reduced number of probes and available sequence information the designed FGAs is at present particularly useful for ecotoxicological laboratory experiments performed with biofilm communities.

Soil particles alter the metabolic profile of Pseudomonas putida grown in the presence of phenanthrene: A vibrational spectroscopy approach Andrea Fanesi * 1 , Asfaw Zegeye 1 , Christian Mustin 1 , and Aurélie Cebron †1

Abstract

In soil, the biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) is strongly influenced by the presence of organic matter and mineral particles. Information regarding how the metabolic profile (i.e biochemical composition) of bacteria is affected by carbon source (simple substrates or PAH) in the presence of soil particles (SPs) is scarce. However, it might be of paramount importance for understanding the bioremediation efficiency of polluted sites. We hypothesized that properties of SPs specifically alter both the micro-niches of bacteria and the availability of the carbon source, affecting in turn PAHs catabolism and cell metabolic profile. To test this hypothesis, the soil dweller Pseudomonas Putida was grown in the absence and presence of different SPs (sand, clay and humic acids) using either phenanthrene or glucose as the sole carbon and energy source. The cell metabolic profiles were identified and differentiated using a combination of vibrational spectroscopy techniques (fast and without sample preparation), such as FT-IR and FT-Raman spectroscopy, and chemometric analysis (PLS-DA). We showed that the metabolic profile of P. putida, (i.e. Raman fingerprints) is influenced by the type of SPs present in the medium, with clay and humic acid affecting it the most. The changes of macromolecules regarded mainly proteins, lipids and nucleic acids. Moreover, in the presence of clay and humic acid a more pronounced discrimination between cells grown on glucose or on phenanthrene was observed, suggesting that specific SPs affect the way cells metabolize carbon. Our results provide new information linking PAHs degradation, bacteria physiology and cell surrounding media.

Availability of mercury to freshwater biofilms: from the gene to the community composition

Abstract

Bioavailability is a key concept allowing to link the changes in the trace metal concentrations and speciation with the intensity of the induced biological effects. However, the link between mercury speciation, bioaccumulation and effects to biofilms is overlooked. This study focusses on the availability of mercury in freshwater biofilms. The amounts of IHg and MeHg accumulated in biofilms were determined. The changes in bacterial, microalgal and fungal communities were followed simultaneously by amplicon sequencing. Biofilms grown in-situ in the Olt River (Romania) reservoirs impacted by Hg-rich effluents from a chlor-alkali platform as well as biofilms exposed to Hg in microcosm were compared. The results revealed a significant correlations between the IHg accumulation in biofilm and the fraction of dissolved Hg non-complexed by natural organic matter. A shift in algal, bacterial and fungal community composition of the biofilms from Olt River and microcosm was observed. However the principal component analysis revealed that in the in-situ grown biofilm in addition to Hg, other contaminants present in the waste water of chlor-alkali production plant, i.e. Na+, Ca2+ and Cl-as well as some water quality variables, i.e. NO3-, SO42-, DOC and Zn contribute to the cominity composition alteration. Nevertheless, an increase in the presence of Hg resistance gene (merA) in both in-situ and microcosme exposed biofilms with the increase of the accumulated Hg was found. The outcomes of the results contribute to the development of biofilm-based indicators in support to efforts of mercury monitoring programs in aquatic systems.

Structural and functional response of river sediment microbial communities to environmental concentrations of copper and arsenic, alone or in mixture

Ayanleh Mahamoud Ahmed * †1,2 , Emilie Lyautey ‡2 , Aymeric Dabrin 1 , Chloé Bonnineau 1 , Bernard Motte 1 , Rosy Christophe 1 , Josiane Gahou , and Stéphane Pesce §1

Abstract

While many metals are known to accumulate in sediments, knowledge about the resulting ecotoxicological effects on sediment microbial communities is scarce. The present study aimed at evaluating the structural and functional impact of chronic exposure to environmental concentrations of copper (Cu) and arsenic (As), alone or mixed together, on river sediment microbial communities. Natural uncontaminated surface sediments collected in a French River (Ain) were spiked with As and Cu at a nominal concentration of 40 mg/kg and then were exposed for 21 days in laboratory channels with overlying waters. The response of heterotrophic microbial communities to metals was evaluated both in terms of genetic structure (using ARISA analysis) and functional potential (using exo-enzymatic, metabolic and qPCR analyses). A pollution induced community tolerance (PICT) approach was also performed to assess if the exposure led to an increase in the capacity of microbial communities to tolerate metals. Our results showed rapid and marked effects of Cu alone on the structure and the functions of the exposed communities. Chronic Cu exposure also induced an increase in community tolerance to Cu, as observed by PICT measurement using beta-glucosidase activity. In contrast, the effects of As were mostly undetectable. Under mixture exposure (Cu+As), the effects were similar or higher than those provoked by Cu alone, depending on the measured parameter. Altogether those findings reveal that metals accumulation in sediments can impact exposed microbial communities thus affecting their functional role in aquatic ecosystems.

Abstract

Sediments act as receptor for contaminants that can accumulate over time thus reaching high concentrations. The main objective of this work was to evaluate the impact of chronic exposure to environmental concentrations of PCB on microbial communities from lake sediments. Sediment cores (n = 52) were collected in Lake Annecy (PCB concentrations < 0.9 ng dw-1 7PCBi) and exposed to 3 treatments: a reference without PCB contamination, a medium contamination (430 ng dw-1 7PCBi) and a high contamination (4300 ng dw-1 7PCBi). Sediments were contaminated using a commercial mixture (Aroclor 1254) and were incubated during 14 days at 6•C with oxygenated overlying water. The resulting effects on communities from depth 0-2 cm, 4-6 cm and 8-10 cm were evaluated independently by assessing microbial enzymatic activities, metabolic potentials, gene abundances and community structure. While PCB exposure modulated bacterial community structure in microbial communities from 0-2 cm depth, PCB exposure did not affect the other descriptors. Microbial communities from 4 to 10 cm depth were not affected by PCB exposure. Our results indicate a limited impact of PCBs on exposed microbial communities suggesting that such exposure would probably not modify their function in lake ecosystems. A low and heterogeneous contamination of the sediment cores could also explain these results. The present work also pointed out methodological challenges to assess PCB ecotoxicological effects on intact sediment columns. If such approaches are necessary to remain representative of the ecosystem, it still raises questions about the contamination procedure and the bioavailability of the contaminants. Concentrations of single substances are often below the maximum residue level imposed by the WFD but few is known about their potential toxicity when present in mixtures. According to their chemical properties, pesticides accumulate over time in POCIS passive samplers deployed in contaminated environments and toxicity of the whole POCIS extracts can be tested after extraction. As phytoplankton plays a key role in the aquatic food web, this study aimed to assess the toxicity of POCIS extracts towards the growth of two marine microalgae, Tisochrysis lutea (haptophyte) and Skeletonema marinoi (diatom). POCIS were placed in three stations along a contamination gradient in small watercourses close to the vineyards plots over four one-month periods. The toxicity tests consisted in 96-h exposures of microalgae to i) POCIS extracts and ii) single substances expected to be present in the extracts, in sterile 48-well microplates incubated under controlled conditions. Each species was exposed to five dilutions of POCIS extracts and six concentrations of single substances. The toxicity was assessed by calculating the growth rate inhibition. The toxicity tests and analyses to chemically characterize the extracts are currently ongoing. The first results showed a dose-response trend for the two microalgae species, with subtle differences in the toxicity depending on the extracts. The testing of complex mixtures from the environment provides additional information regarding the contamination of aquatic ecosystems and enlights the necessity of focusing on mixtures effects, along with single compound toxicity.

Simultaneous removal of azo-dyes and hexavalent chromium by a metal and salt tolerant Pseudomonas sp. ZM183 harboring plant growth promoting traits In this study, a metal and salt tolerant dyes decolorizing bacterial strain, Pseudomonas sp. ZM183, was isolated from an agricultural soil polluted with textile wastewater containing the dyes, metal ions and salts. This strain had the potential to decolorize different azo dyes in the presence of a mixture of heavy metal ions (Cr2+, Cd2+, Zn2+, Pb2+). The individual and interactive impact of four different variables (viz. NaCl content, pH, concentration of yeast extract and level of multi-metal mixture) on decolorization of reactive red-120 by Pseudomonas sp. ZM183 was estimated following response surface methodology (RSM). Based on RSM model, optimal decolorization of reactive red-120 by the strain ZM183 was predicted in the medium containing 12.5 g L-1 of NaCl, pH 8.0, 7.5 g L-1 of yeast extract and a multi-metal mixture (Cr: 20 mg L-1; Pb: 40 mg L-1; Cd: 20 mg L-1; Zn: 40 mg L-1). This strain was also found highly efficient in simultaneous removal of hexavalent chromium (25 mg L-1) and different reactive dyes (100 mg L-1). Moreover, the strain ZM183 was also found to harbor the azoreductase gene amplified through PCR using specific primers. In addition to dye decolorization and hexavalent chromium reduction, this strain was also found to have plant growth promoting traits including inorganic phosphate solubilization and indole acetic acid production. Hence, the isolation and characterization of multi-functional Pseudomonas sp. ZM183 might serve as a potential bio-resource to develop the strategies for integrated bioremediation and plant growth promotion in agricultural soils contaminated with textile wastewaters. Based on seven sampling performed (triplicates), density showed 3.5 times lower value on SPC and FRC compared to PVC. In addition, bacterial succession showed that although pioneer taxa were dissimilar on all the three surfaces, the community on PVC and FRC tend to converge with time whereas biocidal coating tends to diverge.

Biocidal coatings triggers low diversified Alteromonadaceae dominated biofilm community

If Flavobacteriaceae represented critical members of diversified biofilms on PVC, Alteromonadaceae accounted for more than 90% of the community on SPC after 4 days and until 12 days of immersion. Then, bacterial diversity increased progressively, keeping Alteromonadaceae as one of the co-dominant taxa until 75 days of immersion. If pioneer stage on the FRC were also dominated by Alteromonadaceae (around 60%), the rapid increase in diversity reached a higher level than for SPC and promoted the co-dominance of other bacterial families (Rhodobacteraceae, Flavobacteriaceae, ...). A second Mediterranean site, in the bay of Banyuls exhibited dissimilar metal contamination and hydrodynamics especially), allowed demonstrating a higher efficacy of SPC after 75 days of immersion. Furthermore, SPC exhibited dissimilar diversified communities at the 2 immersion sites. In conclusion, community shaping was mainly driven by biocide but also site.

Responses of two strains of the marine microalga Tetraselmis suecica to binary mixtures of two PSII inhibitors Abstract Irgarol (triazine) and diuron (phenylurea) are two biocides commonly used in copperbased antifouling paints. They both act as photosystem II (PSII) inhibitors due to their binding action on the D1 protein in PSII. They are thus particularly toxic to photosynthetic organisms such as microalgae. This study aimed to describe the interactions between the two compounds in binary mixtures towards two strains of Tetraselmis suecica: a wild strain (TW) and a mutant strain (TM) resistant to diuron. The toxicity tests consisted in 96-h exposures to contaminants in 48-well microplates. Each strain was exposed to each substance at 6 concentrations. The binary mixtures were achieved following a fixed-ratio ray design with 5 mixture ratios. The toxicity was assessed by calculating EC50 values based on the 96-h growth rate inhibition. The results were analysed using Concentration Addition (CA) reference model, and Helwett and Volund models for synergy and antagony. The EC50 obtained were: 4.2 ± 0.13 µg.L-1 diuron and 0.65 ± 0.027 µg.L-1 irgarol for TW, when EC50 for TM were 20-fold higher for diuron and almost twice for irgarol. For binary mixtures, a slight but significant concentration-dependent synergy was demonstrated in both strains. To further investigate the mechanisms responsible for such effects, transcriptome analyses (RNAseq HiSeq 3000, paired-end 2x150 bp) were performed from cDNA librairies of both strains in control condition and in condition with 50 % growth rate inhibition after exposure to a mixture. The analyses are currently ongoing.

Exposures of soil microbial communities to realistic antibiotics concentrations: key parameters for environmental risk assessment

Abstract

While the occurrence and persistence of antibiotics in environment are recognized as major environmental and human health issues, their ecotoxicological impacts on soil microbial communities are still overlooked for environmental risk assessment. Most available studies highlight effects on soil microbial communities at antibiotic concentrations or under exposure pathways that are far from realistic conditions. To investigate the relationships between SMX (sulfamethoxazole) availability and impact on microbial nitrogen-cycling communities and antibiotic resistance genes (ARGs), a dose-effect approach was performed, with sludge compost or farmyard manure amended soil microcosms. The organic wastes were contaminated before mixing in soils, to obtain SMX concentration surrounding those usually measured in amended agricultural soils. Microbial descriptors were monitored during 84 days following amendments. The total and available fractions of SMX were quantified by UPLC-MS/MS. At these low but environmentally realistic concentrations, only nitrification was impaired by SMX, in compost-amended soils and little consistent effect was observed on denitrification. However, SMX availability was similar in both compost-or manure-amended soils, thus not explain the short-term effects. A temporal decrease of SMX availability contributed to the nitrification recovery, in compost-amended soils. The dynamics of ARGs were partly explained by SMX gradient, but the duration of the experiment and the type of organic waste influenced the ARGs responses to SMX. Although it is necessary to define normal operating ranges of these descriptors, for further interpretations of their suitability as indicators in risk assessment, nitrification and abundances of ARGs are sensitive descriptors of AB effects on soil microbial functioning.

A pilot experimental installation to evaluate the efficiency of a pharmaceutical industry treatment plant and the resulting decrease in effluents toxicity to aquatic microbial biofilms

Abstract

Pharmaceutical wastewaters are usually characterized by a complex mixture of active substances and metabolites with variable characteristics and composition throughout the year. Accordingly, assessing the efficiency of pharmaceutical industry treatment plants and the resulting decrease in effluent ecotoxicity and ecological risk throughout the treatment process remains very challenging. Microbial biofilms have been proven to be early warning natural assemblages to detect acute and long-term effects produced by toxic substances, including pharmaceuticals. Being composed of both autotrophic and heterotrophic microorganisms exhibiting a large range of sensitivity to many toxicants, biofilms are thus relevant models to assess ecotoxicological risks of effluents by studying effects on microbial structure, diversity and functions. In this context, in collaboration with the pharmaceutical firm SANOFI, we installed a pilot system, connected to the wastewater treatment plant of a SANOFI production factory, to evaluate, throughout the treatment steps, the decrease in chronic and acute toxicity of pharmaceutical production effluents for natural biofilms. The system consists of five artificial outdoor channels, each sub-divided into three compartments to ensure replication, continuously filled with wastewater collected after secondary, tertiary and quaternary treatments, respectively, as well as with stream water collected at the immediate upstream and downstream from the discharge. The chronic and acute toxicity of effluents on natural biofilms will be evaluated by combining structural and functional analysis as well as a pollution community tolerance (PICT) approach using pharmaceutical mixtures directly extracted from passive samplers (Polar Organic Chemical Integrative Samplers, POCIS) immersed for several weeks in the different channels.

Biodiversity of an opportunistic pathogen in the water cycle

Florian Vautrin * 1

1 Laboratoire d'Ecologie Microbienne (LEM) -Université Claude Bernard -Lyon I (UCBL) -16 rue Raphael Dubois, 69100 Villeurbanne, France

Abstract

Rising urbanization waterproofs cities. To avoid flooding, many infrastructures have been set up to manage pluvial water flows, whose infiltration basins. Rainwater loads on dust and pollutants during its passage in the atmosphere and on the ground. These particles rich in pollutants such as PAH, PCB, pesticides... end up on the surface of the infiltration basin to form the so-called "urban sediments". This represents a new ecological niche for microorganisms, such as Nocardia, which are able to degrade these compounds and use it as carbon or nitrogen sources for its growth. Nocardia is an actinomycete opportunistic pathogen witch causes nocardiosis, a granuloma- tous and suppurative infection and would affect about 1 million persons each year around the world. The target patients are mainly immunocompromised.

The aim of this study was to assess the impact of human activity on the enrichment and biodiversity of the pathogenic actinobacteria in anthropised environment such as infiltration basins. The high rate of pollution in anthropised environment lead to a modification of the bacterial communities in enhancing the proliferation of some bacterial species, because of their ability to integrate pollutants in their metabolism. Urban sediments constitute a new ecological niche for some pathogenic species, and so concentrate these bacteria and increase the risk of their dissemination in the environment.

Interaction between dark-septate-endophytes and ectomycorrhizal fungi in the context of trace-element contaminated sites

Abstract

Dark septate endophytes (DSE) are ascomycetous fungi that colonize living plant without causing apparent negative effects. They are characterized by melanized hyphae and microsclerotia within plant roots. High tolerance of DSE to metal pollution and their relatively high abundance in contaminated habitats suggest that DSE might have an important function for host survival in these conditions. Therefore, in the context of phytoremediation assisted by symbiotic fungi, we studied this group of fungi into more details. We first isolated seven DSE strains from poplar roots from metal-polluted sites. Fungal isolates were identified as members of the Phialophora, Phialocephala, Cadophora and Leptodontidium genera. A screening of the strains was performed to select the best promising symbiont. Their were characterized for their plant-growth-promoting abilities through different tests such as production of indol-3-acetic acid, release of volatile organic compounds or production of antifungal compounds. For the most promising strains, an inoculation experiment was performed to monitor the effect of the fungi on the growth of poplar and birch on metal-contaminated soils. Moreover, we also investigated the interaction between DSE and endomycorrhizal fungi through a dual-inoculation of host plant. Finally the use of DSE in the phytomanangement of metal-contaminated soils will be discussed.

Impacts of elevated ozone and temperature on wheat rhizosphere microbial communities

Abstract

Ozone (O3) has increased significantly in recent decades as the result of anthropogenic activities. This gas is responsible for reductions in crop yields and plant biomass production of forest and grassland ecosystems. Rhizosphere microorganisms are in close relation with plant roots. They feed organic compounds released by roots and, as a feed-back, they are involved in improvement of plant fitness. Little is known on the impact of elevated O3 on rhizosphere microbial communities. Our objectives were to access O3 and temperature impacts on wheat physiology, soil parameters and rhizosphere microbial communities. The experiment consisted on a 3 week fumigation with or without O3 (70ppb) of two different varieties of wheat (Premio and Soissons) at two temperatures (20•C and 30•C). Samples without plant were used as controls. The effect of O3 was measured on plant physiological parameters (biomass, CO2 assimilation...), on soil parameters (pH and DOC). Microbial communities' structure, abundance and functions were evaluated by T-RFLP, qPCR and Mi-croRespTM techniques. The results show a significant effect of ozone on plants (in particular by reducing their root biomass) in interaction with temperature (Premio was less resistant to O3 at 30•C). Shifts in the microbial communities' structure were also observed under elevated ozone conditions, with a reduction of bacteria and increase of fungi. These changes were largely shaped by plant physiology and soil properties including pH and DOC. This study provides new insight into our understanding of the influence of O3 and temperature on the interaction between plants and soil microbial communities.

Abstract

Carbon nanotubes (CNTs) are nanomaterials with a wide range of current and developing applications. Their increasing use raises the question of their ecotoxicological impact. In aquatic ecosystems, diatoms account for more than 25% of primary productivity. Diatoms are intimately associated with bacterial communities in benthic biofilms. Diatoms-Bacteria interactions condition the carbon and nutrient cycling. Here, the impact of CNTs on a model ecosystem was assessed. This ecosystem was sampled in the Garonne river, simplified by cultural methods, and was finally constituted by the diatom Nitzschia linearis and a bacterial consortium. This model ecosystem was exposed to CNTs at 0, 0.1, 1 and 10 mg/L. After 6 days, cells were harvested either by filtration at 0.45 µm (to collect all bacteria and diatoms), or by filtration at 5µm (diatoms/"attached" bacteria) followed by filtration at 0.45 µm (planktonic bacteria). DNA was extracted from these filters to measure the abundance of bacteria (qPCR) and to determine the structure of bacterial communities (high-throughput sequencing). A negative effect of CNTs on the abundance of bacteria was evidenced at 50mg/L. Only the planktonic fraction was significantly affected. Besides, CNTs exposure modified the structure of bacterial communities in this planktonic fraction from 1 mg/L. While species affiliated to Bacteroidetes phylum were dominant in planktonic community of control incubations, they were strongly lower at 1 and 10 mg/L. On the contrary, the Proteobacteria phylum increased. These results demonstrate that CNTs impact the bacterial communities at relatively low concentration, with potential disruption of their functions in aquatic ecosystems.

Potential use of a biopolymer extracted from marine waste as antifungal agent

Hassiba Laribi-Habchi * †1 and Ibtissem Galizia 1

1 Functional analysis laboratory of chemical processes -University of Blida 1, Algiers, Algeria

Abstract

For a long time, agriculture across the world was dependent on pesticides. Today, it is influenced by a movement that favours practices that are more sustainable and environmentally safe. To meet these new demands, producers wishing to exploit natural resources and make them profitable must turn to new agronomic practices that combine culture performance and protection at a low environmental cost. In this context, the development of biological polymer able to protect our natural resources is a strategy that is attracting more attention. .Natural and healthy for the environment since it comes from the shells of shellfish, polymer of chitosan is recognized in several fields and areas of activity, especially for its antifungal properties. Currently used extensively in agriculture, it is possible to think that chitosan can also be used in forestry to meet several needs. This study helps to highlight the antifungal properties of chitosan at different concentrations against Aspergillus Niger. The results show a highly significant inhibition at dose of 1 g / l.

Gastrointestinal microbial community changes in Atlantic cod (Gadus morhua) exposed to crude oil

Abstract

Expansion of offshore oil exploration increases the risk of marine species being exposed to oil pollution in currently pristine areas. The adverse effects of oil exposure through toxic properties of polycyclic aromatic hydrocarbons have been well studied in Atlantic cod (Gadus morhua). Nevertheless, the fate of conjugated metabolites in the intestinal tract and their effect on the diversity of intestinal microbial community in fish is less understood. Here, we investigated the intestinal microbial community composition of Atlantic cod after 28 days of exposure to crude oil (concentration range 0.0-0.1 mg/L). Various evidence for altered microbial communities was found in fish exposed to high (0.1 mg/L) and medium (0.05 mg/L) levels of oil concentration. First, altered banding patterns were observed on denaturing gradient gel electrophoresis for samples pooled from each treatment group. Secondly, based on 16S rRNA sequences, higher levels of oil exposure were associated with a loss of overall diversity of the gut microbial communities. Furthermore, 8 operational taxonomic units (OTUs) were found to have significantly different relative abundances in samples from fishes exposed to high and medium oil concentrations when compared to samples from fishes exposed to low oil concentration or no oil. Among these, only one OTU, a Deferribacterales, had increased relative abundance in samples from fish exposed to high oil concentration. The results presented here contribute to a better understanding of the effects of oil contamination on the gut microbial community changes in fish and highlight the importance of further studies into the area of host-microbiome interactions.