Microbial Community Analysis of Modern Ooids Collected Near Panarea Island

Iron ooids--spheroidal grains coated by concentric iron oxide laminae—are key markers in the sedimentary record, yet the mechanisms governing their formation remain contested. To examine the potential roles of hydrothermal activity and microbial mediation, we analyzed modern iron ooids actively forming near Basiluzzo Islet, part of the Panarea volcanic complex (Aeolian Islands, Italy). This site is characterized by intense hydrothermal venting, where Fe-rich, CO2-dominated fluids percolate through seafloor sediments and interact with seawater. During a 2015 research cruise aboard the RV Astrea, unlithified ooid-bearing sediments were collected from 80?m depth for geochemical and mineralogical study. Although biological analysis was not part of the original sampling design, subsamples were later subjected to DNA extraction to explore potential microbial involvement. Microbial presence cannot be ruled out in the sediments, but our data do not support a direct microbial role in ooid genesis at this site. Future work is still required.