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[Background]: Poriferans (sponges) are highly adaptable organisms that can thrive in diverse marine and freshwater environments due, in part, to their close associations with internal microbial communities. This sponge microbiome can be acquired from the surrounding environment (horizontal acquisition) or obtained from the parents during the reproductive process through a variety of mechanisms (vertical transfer), typically resulting in the presence of symbiotic microbes throughout all stages of sponge development. How and to what extent the different components of the microbiome are transferred to the developmental stages remain poorly understood. Here, we investigated the microbiome composition of a common, low-microbial-abundance, Atlantic-Mediterranean sponge, Crambe crambe, throughout its ontogeny, including adult individuals, brooded larvae, lecithotrophic free-swimming larvae, newly settled juveniles still lacking osculum, and juveniles with a functional osculum for filter feeding., [Results]: Using 16S rRNA gene analysis, we detected distinct microbiome compositions in each ontogenetic stage, with variations in composition, relative abundance, and diversity of microbial species. However, a particular dominant symbiont, Candidatus Beroebacter blanensis, previously described as the main symbiont of C. crambe, consistently occurred throughout all stages, an omnipresence that suggests vertical transmission from parents to offspring. This symbiont fluctuated in relative abundance across developmental stages, with pronounced prevalence in lecithotrophic stages. A major shift in microbial composition occurred as new settlers completed osculum formation and acquired filter-feeding capacity. Candidatus Beroebacter blanensis decreased significatively at this point. Microbial diversity peaked in filter-feeding stages, contrasting with the lower diversity of lecithotrophic stages. Furthermore, individual specific transmission patterns were detected, with greater microbial similarity between larvae and their respective parents compared to non-parental conspecifics., [Conclusions]: These findings suggest a putative vertical transmission of the dominant symbiont, which could provide some metabolic advantage to non-filtering developmental stages of C. crambe. The increase in microbiome diversity with the onset of filter-feeding stages likely reflects enhanced interaction with environmental microbes, facilitating horizontal transmission. Conversely, lower microbiome diversity in lecithotrophic stages, prior to filter feeding, suggests incomplete symbiont transfer or potential symbiont digestion. This research provides novel information on the dynamics of the microbiome through sponge ontogeny, on the strategies for symbiont acquisition at each ontogenetic stage, and on the potential importance of symbionts during larval development.

422 p, Entre los años 2013 y 2016, el concepto de autonomía estratégica comenzó a emplearse en la Unión Europea (UE) en ámbitos muy específicos, como los de seguridad y defensa. En apenas una década el contenido de este concepto se enriqueció y su uso se extendió a sectores como los de la salud y las energías, las cadenas de valor y suministros estratégicos. En la actualidad, la autonomía estratégica se proyecta en casi todas las áreas políticas de la Unión. Defender los intereses de la UE en un entorno geopolítico hostil y mitigar la dependencia respecto a cadenas de suministro extracomunitarias, son citados como ejemplos de una autonomía estratégica que ha pasado de ser un concepto a ser una capacidad. Esta imperiosa necesidad de actuar ante distintos retos comunes de la Unión ha contribuido a hablar incluso de soberanía europea. Esta obra colectiva es una de las primeras obras monográficas publicadas hasta la fecha sobre esta materia. Desde diferentes enfoques y disciplinas, se ofrece, por una parte, una interesante panorámica de los conceptos de autonomía estratégica y de soberanía europea. Esas discusiones marco son completadas, de otra parte, con trabajos que abordan las proyecciones de la autonomía estratégica en relevantes áreas políticas de la Unión Europea, como es caso del control de fronteras, la seguridad y defensa o la salud.