Team ECOMAP - Ecology of Marine Plankton

Despite their impact on a planetary scale, we still know relatively little about the composition of many of these microbial communities and even less about how they interact, function at the ecosystem level and adapt to ecological niches in a rapidly changing world. One of the main strengths of the ECOMAP team is to gather members with expertises on all size classes of plankton, including viruses, heterotrophic and photosynthetic prokaryotes, protists and other microeukaryotes, and covering a large spectrum of trophic modes (e.g., symbiosis, parasitism, kleptoplastidy, mutualism, etc.). Furthermore, these organisms are studied at all levels of organization from molecules (DNA, proteins, metabolites), cells, communities, to ecosystems and global ocean. Such a unique holistic approach, combining laboratory work on cultures of ecologically relevant model organisms and in situ studies, allows the ECOMAP team members to tackle many aspects of the structure, dynamics and ecological functions of planktonic communities, thereby linking the diversity, ecology, physiology and evolution of planktonic microorganisms.

We structured our project into three unifying research axes, which integrate our complementary scientific interests, skills and expertises.

Thematic Axes

Structure and dynamics of planktonic communities

Determine how the diversity, abundance, and dynamics of marine plankton communities are shaped by physical, chemical, and biological factors over different spatial and temporal scales, using a combination of flow cytometry, imaging, culture, molecular and meta-omics approaches. We rely on large datasets either retrieved from public databases or generated by members of the team from specific cruises/samplings of opportunity (TONGA, APERO, REFUGEARCTIC, MOOSE, BIOcean5D, etc.), time series (SOMLIT-ASTAN, BOUSSOLE, HOT, BATS, BLANES, etc.) as well as global expeditions (Tara Oceans, TREC, EMO-BON, BioGeoSCAPES, etc.)

Biotic interactions in marine ecosystem

Determine the nature, diversity and relevance of symbiotic associations for the productivity, resilience, connectivity, and recycling capacity of marine communities, notably in the context of global change, using various approaches: i) direct observations linking state-of-the-art automated high-resolution cell imaging to single-cell omics, ii) isolation of parasites and their host for use in mono- and co-culture experiments in the laboratory, and iii) genomics, transcriptomics, proteomics and/or metabolomics to assess biological changes related to the interactions between partners. We notably explore how the extended phenotype of holobionts plays a role in processes such as cell-to-cell communication, resistance to pathogens and grazers, facilitation for mutualistic symbioses, kleptoplastidy, adaptation to novel habitats, sexual reproduction as well as nutrient cycling and carbon export.

Adaptation and acclimation to the marine environment

Another goals of the ECOMAP team is to study the capacity of free-living or symbiotic planktonic organisms to acclimate (physiological plasticity) and adapt (acquisition/loss or alteration of genes) to variations of biotic and abiotic (temperature, light, availability in N, P, Fe, etc.) factors, notably in the context of global change. To do so, we use a cross-scale systems biology approach, including comparative physiology, genetics (CRISPR), (meta)omics and network approaches to describe and model i) the phenotypic plasticity of representative species or ecotypes (e.g. growth rate, trophic status or activity of key proteins in different conditions), and ii) the molecular and metabolic processes underlying adaptation to the various ecological niches. Members of the ECOMAP team are working on a variety of organisms covering a large range of sizes, including several model organisms, among which a particular focus is given on marine picocyanobacteria that can be studied at all levels of organisation from the genes to the global ocean.