Do different sponge species host different benthic communities?

Sponges (Phylum Porifera) are ancient organisms that play key roles in marine benthic ecosystems, filtering water to cycle nutrients and improve water quality. Their complex structures offer habitats for various organisms and serve as refuges for small species, such as meiofauna, which contributes to benthic biodiversity. By filtering water, sponges also collect particulate matter from their surroundings, including genetic material of local organisms, potentially providing insights into their species diversity. To investigate sponge-associated communities, sponge samples and the surrounding water were collected from different sites around Tenerife. First, sponge species were identified by molecular approaches using the COI and 28S markers. Then, metabarcoding combined with eDNA recovered by sponges allowed the detection of fish and fungi communities. Meiofauna living within sponges and found in the surrounding water was identified to broad taxonomic groups, and community structures in each sponge species was investigated. Results revealed at least five different sponge species across the samples, Aplysina aerophoba, Axinella damicornis, Crambe crambe, Ircinia oros and Scopalina canariensis, with other samples requiring a longer identification process. All the analyzed communities showed no significant differences among sponge species but revealed high variability within samples of the same species. Nevertheless, the results allowed to assess the local benthic diversity, confirming the role of sponges in capturing a wide range of organisms in their environment. This study highlights the benefits of combining morphological and molecular methods to deepen our understanding of sponge-associated communities and points to sponges as a useful tool in monitoring marine biodiversity.