XPADE

Xenobiotic Pressures : Adaptation and Dysfunction of Ecosystems

Animator : Muriel RAVETON

Despite considerable progress in ecotoxicology, a new paradigm is needed to answer the central questions of this theme, such as « What are the effects of xenobiotics on organisms ? » and « How are ecosystem functions affected by xenobiotics ? ». Many authors argue that the current bottom-up approach to ecotoxicology, which involves the use of small-scale experiments to predict effects on entire ecosystems, must be merged with an ecological top-down approach that focuses directly on large-scale ecological effects.

To address these urgent and current challenges, we aim to combine LECA’s advanced ecology/evolution research and ecotoxicology to adopt an innovative approach in this scientific field, in particular by using integrative observation and experimentation approaches.

XPADE’s research combines a bottom-up approach - studying how different phenotypes are expressed from the same genotype in response to pollutants - with a top-down approach - focusing on understanding the role played by xenobiotics in genotype selection in ecosystems.

XPADE research is based on comparative (multiple organisms and multi-pollution), integrative (multi-level biological integration research), and ecosystem (biodiversity and food webs) approaches.

XPADE addresses three main challenges which are :

1. How can we realistically study the impacts of xenobiotics at the organism and sub-organism level ?

 

The correlation between exposure to xenobiotics and their effects is studied at the organism level (toxicity, resistance, body size, growth fertility, etc.) and at the suborganism level (gene expression, endocrine disruption, etc.).

The challenge is to understand the mechanisms involved in phenotypic plasticity in the presence of :

  • (i) realistic multi-pollution pressures
  • (ii) natural variability of the surrounding parameters (UV, temperature...).

The integration of cross effects on the organism’s responses will be essential to :

  • (i) identify the confounding factors
  • (ii) predict effects on population dynamics at the ecosystem level, using modelling tools.
2. How can we estimate the long-term impacts of pollutants under controlled conditions ?

 

The assessment of large-scale effects of ubiquitous pollutant mixtures (at environmentally realistic levels) will be studied on a multi-generational scale. Such exposures are rarely studied mainly for practical reasons, with consequently few datasets on adaptive processes in a population.

We recently developed two types of multi-generational studies :

  • one in microcosm (insects with short generation time)
  • another in mesocosms (trans-generational study on models such as amphibians with longer life cycles).
3. How can we estimate the effect of pollutants in a world of multiple environmental stresses ?

 

Patterns of abundance, distribution, diversity and adaptation will be studied in the presence of realistic xenobiotic pressures, located in very well defined natural areas. The (meta)data obtained from these approaches will highlight the adaptation of local species to the combined criteria (xenobiotics, environmental parameters, temporal variability).

These species will be of interest to :

  • (i) investigate the mechanisms involved in chemical tolerance
  • (ii) use them in remediation strategies.

Such a holistic top-down approach will provide accurate large-scale predictions of ecosystem alterations induced by xenobiotic pressures.

 

Who is involved ?

Researchers / Professors :

– Marie-Noëlle BINET
– Jean-Philippe DAVID
– Arnaud FOULQUIER
– Bello MOUHAMADOU
– Muriel RAVETON
– Stéphane REYNAUD
– Sophie SRODA

Research assistants :

– Thierry GAUDE
– Frédéric LAPORTE
– Sophie PERIGON
– Sylvie VEYRENC

 

What are the ongoing projects ?

Projects
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