Prokaryotic microbiome of control and translocated sponges Petrosia ficiformis and Ircinia oros.

Sponges (phylum Porifera) are marine invertebrates whose success probably derives from their remarkable ability to effectively filter the suspended material in the water column, whether organic or inorganic. Not surprisingly, sponges are recognized as bio-indicators and bio-remedies. These organisms are also holobiont, they permanently host a bacterial community (about 60 Phyla) which contribute to the survival and functioning of the host itself. Sponge associated bacteria can varies both between different species and between conspecific individuals, probably under the influence of environmental factors. The aim of this work is to investigate the response of the microbiome of two species of sponge (Petrosia ficiformis and Ircinia oros) following translocation in urban area. The experiment took place from September 2020 to July 2021. Sponge fragments were taken from the locality of Nisportino (LI) and moved to a breeding plant (consisting of frames and nets) located at the dock in Portoferraio (Elba Island). The bacterial microbiome of the two species of sponge was characterized by the metabarcoding approach, through sequencing on Illumina MiSeq platform of the V3-V4 region of 16S rRNA gene. Analysis of microbiome composition was conducted using the open source program QIIME 2 and revealed the prevalence of microbial phyla known to be commonly associated with sponges. Multivariate variance analysis found significant differences in the composition of the microbiome between the two sponge species, suggesting an effect of the host identity in selecting symbionts. The effect of translocation was also highly significant in the composition of the sponge microbiome, although the two species responded differently to the translocation.