Diving into the Deep: Fungal Diversity in the Newly Discovered Hydrothermal Vents of Hatiba Mons, Red Sea

Junia Schultz¹Sharifah Altalhi^1,2Alexandre Soares Rosado^1*

• ¹King Abdullah University of Science and Technology Biological and Environmental Science and Engineering Division, Thuwal, Saudi Arabia
• ²Taif University, Taif, Saudi Arabia

Hydrothermal vents represent one of Earth's most extreme ecosystems, marked by high temperatures, elevated metal concentrations, and sharp chemical gradients that support specialized microbial life. While bacterial and archaeal communities in these environments have been extensively studied, fungal diversity remains largely unexplored. The Hatiba Mons hydrothermal vent field, recently discovered in the Red Sea Rift, offers a unique opportunity to investigate fungal communities in a geochemically distinct environment characterized by hypersalinity and high metal content. In this study, we offer the first high-resolution analysis of fungal diversity across crusts, sediments, and microbial mats collected from five active hydrothermal vent sites within Hatiba Mons. A total of 38 subsamples were obtained using a remotely operated vehicle (ROV) Código de campo alterado Código de campo alterado Código de campo alterado during the KRSE Aegaeo RV cruise in May 2022. DNA was extracted and the fungal ITS rRNA gene region was amplified and sequenced using Illumina MiSeq. Sequence processing and taxonomic assignment were conducted with QIIME2 and the UNITE database, and downstream analyses were performed in R using the phyloseq package. Fungal community composition was visualized through bar plots and species heatmaps, and diversity metrics were assessed using alpha-and beta-diversity indices. Principal Coordinates Analysis (PCoA) revealed significant differences in community structure across sample types, supported by PERMANOVA. Functional profiling with FUNGuild suggested diverse ecological roles, including saprotrophic, symbiotic, and pathogenic lifestyles. Our findings highlight previously undocumented fungal diversity in the Hatiba Mons hydrothermal system, dominated by Ascomycota, Basidiomycota, and Chytridiomycota. The distinct taxonomic and functional profiles observed suggest that fungi in the Hatiba Mons vents may play important roles in biogeochemical cycling and ecosystem dynamics. This study expands our understanding of fungal ecology in extreme marine environments and underscores the importance of including fungi in future deep-sea microbiological research.