Seagrass meadows are among the most productive marine ecosystems, playing essential structural and functional roles, and are recognized as the most efficient blue carbon sinks globally. The plant-associated microbiome, a diverse array of microbial taxa forming intimate symbiotic relationships with seagrasses, is critical for maintaining ecosystem stability and facilitating plant adaptation to environmental stressors. In the Mediterranean Sea, however, the endemic seagrass Posidonia oceanica is in decline due to climate change-driven stressors, particularly thermal stress. The sponge Chondrilla nucula is commonly found in association with P. oceanica, and it is hypothesized that this sponge-plant symbiosis enhances the metabolic capabilities of both organisms, mediated by key microbial communities, especially under thermal stress. Despite this potential, the precise dynamics of nutrient exchange and interactions between seagrasses and sponges, facilitated by their microbiomes, remain poorly understood. This knowledge gap limits our ability to fully comprehend the ecological and metabolic functions of these associations and hinders the development of nature-based solutions to mitigate the impacts of climate change. MicroSymb aims to address this gap by studying the P. oceanica–C. nucula association through their microbiomes, utilizing field sampling, mesocosm and stable isotope probing experiments, metabarcoding, and meta-omics approaches. This project will evaluate the capacity of this association to adapt and remain resilient in the face of ocean warming. Throughout MicroSymb, I will acquire advanced skills in metagenomics, metaproteomics, and nutrient cycling within holobionts, while contributing my expertise in marine ecology, host-microbiome interactions, holobiont functioning, molecular biology, and bioinformatics. MicroSymb will position me at the forefront of host-microbiome research and the study of adaptive capacities in marine organisms amid climate change.

Plastic debris contamination is a growing environmental concern in marine habitats. Large plastic objects break-up over time to create micro- and nano- particles, collectively called microplastics (MP), which account for the overwhelming majority of plastic particles in the sea. Little is known about the impacts of MP on wildlife or humans and this presents an important research priority. Several studies have demonstrated that MP can affect sea life negatively. Amongst these, they have been reported affecting development (causing malformations, delayed growth and increased death rates). These developmental effects have never been characterised, and their molecular basis remains unknown. Developmental defects may impact population survival by decreasing the number of individuals, or their fitness, in range of marine organisms. This pioneering project will identify the effects of MP exposure in the development of the sea urchin Paracentrotus lividus, bridging interests for ecology, toxicology, developmental biology and aquaculture. I will characterise the developmental morphological malformations caused by MP and their underlying genetic mechanisms. This Fellowship will provide an excellent opportunity to complement my strong background in genetics and molecular and developmental biology and expertise in ecotoxicology and microplastic pollution with transcriptomic analysis and the deep understanding of this model organism for development and toxicology under the supervision of Dr. Arnone, a world leading expert in the field. This will provide me with a firm skill set and knowledge to further my research career. The knowledge and expertise I will acquire in the Arnone lab, together with being hosted by a supportive and acclaimed institution, and the prestige of the MSCA fellowship, will allow me to open a unique and timely line of research and will be crucial for my transition into an independent European researcher.

Current degradation of marine ecosystems, worsen by global change processes, have triggered scientific and public awareness for environmental conservation. That is the case of seagrass meadows, unique coastal habitats which provide a variety of ecosystem services, play essential roles in coastal ecology and biogeochemistry and are endangered by human development. Even though seagrass restoration might be locally helpful with some species, in the case of the iconic Mediterranean species Posidonia oceanica, conservation and recovery of the existing meadows is the most urgent topic to be addressed. However, there is a lack of knowledge regarding the active strategies which could be applied to enhance present meadow's tolerance and future resilience to environmental stressors. Through an interdisciplinary approach based on assisted genetic migration, active priming strategies, assisted ecological succession and science communication, SEACOVERY project will explore new insights into assisted recovery techniques and increase awareness in local communities. My experience in seagrass ecotoxicology and population dynamics will be complemented with the recognised expertise on assisted evolution and transcriptomic responses of Dr. Gabriele Procaccini (SZN, Italy), combined with the essential knowledge on seagrass physiological and ecological responses to environmental stressors of Dr. Lázaro Marín-Guirao (IEO-CSIC, Spain). The outreach of this research will be augmented thanks to the placement with the CSI Gaiola onlus, which will support science communication and education events. SEACOVERY will provide an urgently needed knowledge on assisted natural recovery of P. oceanica meadows, with the potential of being a cost-effective climate change mitigation strategy.