Prokaryotic diversity in the sponges Mycale (Oxymycale) acerata (Kirkpatrick, 1907) and Dendrilla antarctica (Topsent, 1905) from two distant Antarctic marine areas: South Cove at Rothera Point (Adelaide Island, Western Antarctic Peninsula) and Thetys Bay (Terra Nova Bay, Ross Sea).

The Antarctic environment offers a unique opportunity to study the interactions between Porifera and their microbial symbionts. Reports on the association between prokaryotes and Antarctic sponges are increasing. However, a comparison of the bacterial communities associated to the same sponge species but inhabiting different Antarctic areas has seldom been addressed. This study explored the prokaryotes associated with the sponge species Mycale (Oxymycale) acerata (Kirkpatrick, 1907) and Dendrilla antarctica (Topsent, 1905) collected from South Cove at Rothera Point (Antarctic Peninsula) and Thetys Bay (Ross Sea). In D. antarctica, some groups were equally represented at both sites (e.g., Amylibacter, Cutibacterium, Yoonia-Loktanella), whereas members in the genera Polaribacter and Kistimonas were more abundant in Rothera. Similarly, M. acerata individuals collected from Rothera showed a higher relative abundance of some bacterial genera, such as Polaribacter, Sulfitobacter, and Ulvibacter. The results allowed us to identify some taxa common to sponges belonging to the same species and highlighted the possible influence of site-specific environmental conditions in shaping symbionts.