Lipids as Indicators of Pollution In Diatoms: towards an integrated ecotoxicity framework for aquatic and terrestrial plants (Irstea / UMR EPOC in partnership with UMR LBM)
The strong development of human activity during the 20th century led to a significant increase in organic, trophic and toxic pollution around the world. In Western Europe, even if a successful effort has been done to better assess and master organic and trophic enrichment, toxic pollutants still appear as a major actual issue. Thus, a sustainable development of our society in respect to the natural environment needs a better control of the non-intentional effects of micropollutants (such as agricultural pesticides). The WFD (*) sets as an objective to achieve the good ecological status in the EU shortly and recommends benthic diatoms as one of the key BQEs (**) for the assessment of freshwater hydrosystems. So, diatomic indexes based on the benthic community composition are routinely used by surveillance networks and provide a good diagnosis of manmade organic or trophic enrichment, but they fail at properly assessing toxic effects in situ. The use of biomarkers then appears as a promising way (more specialized, more sensitive), but still needs some specific developments. The LIPID Project, coming in tight complementarity with another just started LabEx project (PhytoCOTE, 2015-2018), focuses on the same pilot zone of the Blayais vineyard (north of the Gironde Estuary). Its first aim is to develop an ecotoxicological approach based on biomarkers to assess the influence of toxic pollution both on its terrestrial and aquatic vegetal compartments. For that, a new lipid biomarker already validated on terrestrial plants for the assessment of polluted soils will first be used to implement a compared toxicity diagnosis along a gradient of pollution found between a terrestrial environment of the pilot zone and the benthic diatoms of its aquatic environment. Then an experimental approach combining in-labcontrolled and in situ exposure protocols will be performed in order to validate this new biomarker for aquatic uses, in comparison with the responses of a set of general or physiological descriptors and transcriptomic biomarkers already mastered by our teams on diatoms.
(*) WFD: Water Framework Directive
(**) BQE: Biological Quality Elements