Cyanobacteria and lake ecology
I am part of a team that dedicates its research to Cyanobacteria, cyanotoxins and environment. I am leading projects dealing with the ecology of peri-urban lakes, and projects that explore the untapped diversity of mangrove benthic Cyanobacteria.
ANR Project COM2LIFE
Microbial communities in Ile-de-France Lakes: taxonomic and functional diversity
Peri-urban lakes are of major significance to urban ecology and to the public. Apart from the phytoplankton, investigated because of their importance, knowledge of microbial communities and their functions is still scarce. Understanding the effect of eutrophication, an indicator of anthropization, on freshwater bodies is an archetypal “One Health” problem. Indeed, the interdependencies between ecosystem, animal and human health are so strong, particularly in peri-urban areas, that holistic approaches must be adopted to adequately and simultaneously address the issues of environmental health and human well-being. However, larger-scale evaluation of the effect of eutrophication lakes microbiome is currently mostly lacking.
The ANR project COM2LIFE aims at evaluating the effect of eutrophication on the biodiversity of microbial communities occurring in peri-urban lakes. Specifically, it investigates the taxonomic and functional diversity of microbial communities that consist in Archaea, Bacteria, Eukarya, and viruses in the water, sediment and fishes of lakes along a eutrophication gradient in the populated Ile-de-France region. COM2LIFE will test two hypotheses. The first is that the spatial and temporal heterogeneity of environmental factors related to anthropogenic pressure at the regional scale result in differences in the taxonomic and functional diversity of lakes microbial communities (H1). The second is that the microbial communities observed in the water column, sediment, and fish compartments may vary in space and time, but that the functions they provide are conserved (H2) due to functional redundancy among the different organisms and compartments.
The project will thus identify the biotic and abiotic parameters that constrain community compositions and functions at the lake and regional scales and the influence of eutrophication levels. This approach has the potential to provide new candidate bioindicators for evaluating anthropic pressure and water/ecosystem quality.
Taxonomic, genomic and metabolic diversity of Cyanobacteria
Cyanobacteria and eukaryotic microalgae are key players in life on Earth. They have adapted to a broad diversity of ecosystems, and ensure roughly half of the primary production. Their detailed study greatly benefits from isolated strains, deposited and maintained ex situ in culture collections, and made available to the scientific community along with expert knowledge. Established in the late 1920s, the culture collection of cyanobacteria and microalgae at the French National Museum of Natural History (MNHN) now comprises over 1350 non-axenic live strains isolated mostly from freshwater ecosystems in France.
As part of my research projects I contribute to a collective effort to enrich the collection, notably with new strains from mangrove ecosystems (Mayotte, Guadeloupe) which are currently being described along with their genomic characterization. We also try to characterize their metabolic potential as producers of bioactive molecules.
