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Dynamique des communautés microbiennes des biofilms phototrophes à différents niveaux d'intégration biologique : des successions écologiques aux réponses à l'exposition à un herbicide

Abstract : The intensive use of pesticides causes many disturbances in aquatic ecosystems, which are well known to offer a range of "ecological services" for society. In terms of ecotoxicology, environmental issue is not limited to the risk assessment of a pollutant toxicity on organisms but it expands to the ability to assess, at the ecosystem scale, the consequences of a disturbance and the use of bio-indicators. In this context, for aquatic ecosystems, phototrophic biofilms provide a particularly relevant model, based on their complex microbial community structures, spatial and temporal dynamics and variety of functions. In a first experiment our results suggested that microbial aggregates from different habitats (activated sludge and phototrophic biofilm) are characterized by comparable potential of an herbicide biodegradation: alachlor. Then using an ecological approach, a manipulation of the structure of phototrophic biofilms microbial communities was explored in "natural" conditions in rivers exhibiting different physicochemical characteristics, and in "controlled" conditions with a photosynthetic bioreactor prototype (Taylor - Couette flow type). These experiments suggested that the microbial community structures are driven by autogenic and allogenic factors, depending upon maturation state. Finally using an ecotoxicological approach, structural and functional responses of phototrophic biofilms exposed to alachlor were evaluated, integrating the maturation stage (autogenic factors) and history (allogenic factors) of phototrophic biofilms. This work allowed us to undertake an ecotoxicological approach integrating the concepts of ecological succession in microbial communities. Our results demonstrate that phototrophic biofilms are promising tools as bio-indicators of water quality when they are characterized by a multi-metric approach including functional and structural descriptors.
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https://tel.archives-ouvertes.fr/tel-00741353
Contributor : Williams Exbrayat <>
Submitted on : Friday, October 12, 2012 - 1:43:28 PM
Last modification on : Thursday, October 15, 2020 - 4:07:30 AM
Long-term archiving on: : Saturday, December 17, 2016 - 12:19:51 AM

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  • HAL Id : tel-00741353, version 1

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Armelle Paule. Dynamique des communautés microbiennes des biofilms phototrophes à différents niveaux d'intégration biologique : des successions écologiques aux réponses à l'exposition à un herbicide. Biodiversité et Ecologie. Université Paul Sabatier - Toulouse III, 2012. Français. ⟨tel-00741353⟩

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