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Agenda > SessionsSession 1 Impact of contaminants on microbial functions
Biogeochemical cycles, element recycling and energy flows are mostly relying on the numerous functions supported by microbial communities. Primary inputs of carbon and nitrogen to the biosphere, silicon cycling, anaerobic processes, aggregate stabilization and water retention… in soils, sediments, and water, support the needs of larger organisms and related functions, and provide irreplaceable basis to several ecosystem services (e.g. agriculture). As a consequence, any perturbation caused by micro-organism exposure to contaminants is likely to trigger direct or indirect effects at higher levels of biological organization resulting in altered ecosystem functioning. Furthermore, microbial communities exhibit adaptive responses to pollution pressure which may result in fitness costs, reducing microbial ability to cope with additional environmental changes. In term of indicators, functional tolerance acquisition to chemicals can be used to disclose undocumented pollution. Thanks to significant increases in the depth of functional analysis gained by the spreading of -omics, metabolome, proteome and transcriptome provide new insights on the effects of chemical stressors on micro-organisms and their functions. This session welcomes lab-to-field studies, addressing the impact of contaminants on microbial functions from the molecular, cellular to the community level in interaction with the environment. Validation of -omics approaches will also be of special interest, in the global frame of adaptation to pollution pressure in the microbial world.
Keywords: functional -omics, functional ecotoxicology, ecosystem functioning Keynote by Prof. Sara Hallin, Swedish University of Agricultural Science, Sweden
Session 2 Microorganisms in complex systems: biological interactions, pollution & climate change
Risk assessment of pollution is challenged by the fact that multiple stressors proceed together on complex interconnected biological communities in ecosystems. Causality from chemical exposure to community responses and ecosystem alteration remains therefore often unclear hindering the identification and prioritization of stressors. This lack in mechanistic understanding may explain the failure of several indicators in complex exposure situations. To face such a challenge, there is a need to develop microbial ecotoxicological approaches and indicators adapted to evaluating and predicting microbial interactions with multiple contaminants as well as with contaminants and other environmental stressors, which can modulate both the exposure and the sensitivity of micro-organisms to toxicants. In addition, since microorganisms play a pivotal role in food webs, it appears essential to take into account the complex array of interactions between micro- or micro-macro-organisms and their environment under pollution pressure. Keywords: interactions of chemical and non-chemical stressors, multivariate statistical analysis, interactions modeling, food web Keynote by Helena Guasch, Blanes Centre for Advanced Studies, Spain
Session 3 Microorganisms role in contaminants (eco)dynamics & application to bioremediation
To cope with the presence of toxic elements in their environment, microorganisms have developed diverse metabolic or resistance mechanisms. Microbial activity may have considerable impact on the fate and behavior of contaminants in the environment, largely contributing to their ecodynamics. While processes such as biodegradation or immobilization (sequestration, precipitation) contribute to the mitigation of the pollution, other activities may on the contrary generate pollution or contribute to its spreading. From lab-to-field, evaluation and understanding of underlying processes is still challenging, and prediction of the fate of contaminants in ecosystems remains difficult. In parallel, numerous microbial-based systems are already in use to mitigate pollution from complex solid or liquid wastes. The relation between chemical evidence of biodegradation and the identity of microbial 'degraders' is generally indirect and overlooked, which makes pollution fate prediction difficult in complex ecosystems. The nature of organisms involved in biodegradation or biotransformation steps needs to be enlightened as many species or phyla are still rarely considered (for example Archaea). Bioavailability and distribution of chemicals needs special attention, being the factor which limits micro-organisms access and transformation of chemicals.
Keywords: bioremediation, biodegradation, biotransformation, bioavailability, metabolization, retroactive action, ecological engineering Keynote by Prof. Jonathan LLoyd, Manchester University, United Kingdom
Session 4 Microorganisms for environmental risk assessment
Climate change drives dramatic shifts in ecosystems, whereas pollution evolve according to human activities. Arising concerns regarding emerging contaminants such as nanoparticles, pharmaceuticals or micro- and nano-plastics, persistent organic contaminants (chlordecone, fluorinated organics…) as well as legacy pollution are still to manage. One of the primary objectives of ecotoxicology is to promote innovative methods and tools for environmental risk assessment, including predictive hazard and risk assessment as well as in situ evaluation of environmental quality and ecotoxicological impacts in contaminated environments. Despite the recognized importance of microbial communities in supporting a range of ecosystem functions and services and their ubiquity in all ecosystems, micro-organisms are only rarely considered in a priori environmental risk assessment and they are typically not yet considered by regulation or legislation. Even if chemical analysis remains essential to evidence contamination, bioindicators can provide valuable complementary information on both the impact and fate of contaminants and help to identify chemical-induced risks not covered by analytics. The ubiquity of micro-organisms in the environment and their capacity to adapt to a large range of contaminants make them good candidates as exposure and effects indicators, allowing them to contribute to the a posteriori environmental risk assessment.
Keywords: bioassay, bioindicator, biomarker, ecosystem health Keynote by Prof. Christian Griebler, University of Vienna, Austria
Session 5 Microbial ecotoxicology: from research to end-users
A special space will be dedicated to the input of scientific knowledge in microbial ecotoxicology to management of environmental pollution and vice versa. Conversely, use-inspired studies would be of special interest, where topical cases are at the root of research. At a larger scale, any development of international regulations such as EU framework directives based on microbial ecotoxicology would be acknowledged. Case studies are together welcomed in this session, which will also benefit of communications from national and local management structures. A satellite conference (in French) dedicated to public and private partners is also planned to extend the dissemination to a broader audience.
Keywords: case studies, environmental pollution management Keynote by Prof. Isabelle Lavoie, INRS, Canada
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