Understanding the hidden yet colorful diversity of coralligenous sponges and its vulnerability to environmental changes – I_SEA_RAINBOWS

The Mediterranean coralligenous ecosystems are rich in biodiversity but they are under increasing threat due to climate change. Among the key inhabitants are the colorful Oscarella sponges, which cover up to 37% of the coralligenous seafloor covered by sponges in some regions. Yet, they remain largely understudied. Recent genetic discoveries in the Bay of Marseille have revealed several new species, hinting that much of this sponge diversity remains unknown.
The project is built around three main hypotheses: (i) the diversity of Oscarella sponges is far greater than currently recognized, and many species may be endemic to the Mediterranean; (ii) these sponges are particularly sensitive to environmental changes, especially changes in temperatures, which could significantly alter their populations; (iii) the striking color diversity seen in these sponges genus may be linked to genetic mechanisms and serve important physiological functions.
The research will be conducted through three work packages (WPs). WP1 focuses on characterizing Oscarella species along the French coasts and the entire Mediterranean Sea through field surveys and genetic analysis. WP2 will monitor how these sponges respond to temperature changes in situ, tracking their growth and health using cutting-edge photogrammetry techniques. WP3 will investigate the molecular basis of their color diversity, aiming to identify pigments and assess their potential roles through transcriptomics and proteomics.
By integrating ecological surveys, advanced molecular biology, and bioinformatics, this project will not only expand our knowledge of Oscarella biodiversity but also explore how these species are likely to cope with future environmental changes. Additionally, it will provide new insights into the molecular underpinnings of pigmentation in marine sponges, with potential broader applications in cell biology and biotechnology.