Fungal diversity associated with Goa's tarballs: Insights from ITS region amplicon sequencing.

This study explores the fungal diversity associated with tarballs, weathered crude oil deposits, on Goa's tourist beaches. Despite tarball pollution being a longstanding issue in Goa state in India, comprehensive studies on associated fungi are scarce. Our research based on amplicon sequence analysis of fungal ITS region fills this gap, revealing a dominance of Aspergillus, particularly Aspergillus penicillioides, associated with tarballs from Vagator and Morjim beaches. Other notable species, including Aspergillus sydowii, Aspergillus carbonarius, and Trichoderma species, were identified, all with potential public health and ecosystem implications. A FUNGuild analysis was conducted to investigate the potential ecological roles of these fungi, revealing a diverse range of roles, including nutrient cycling, disease propagation, and symbiotic relationships. The study underscores the need for further research and monitoring, given the potential health risks and contribution of tarball-associated fungi to the bioremediation of crude oil-contaminated beaches.

High abundance of Vibrio in tarball-contaminated seawater from Vagator beach, Goa, India.

Tarballs are semi-solid remnants of crude oil and they are formed in marine environment after oil-spill incidents. They are composed of diverse hydrocarbons; some of which are recalcitrant in nature. Recent studies based on amplicon sequencing of 16S rRNA gene suggested that tarballs support hundreds of bacterial genera and provided insights into their role as hydrocarbon degraders and potential human pathogens. In this study, bacterial composition of tarball-contaminated seawater from Vagator beach, Goa, India was characterized by amplicon sequencing of V3-V4 regions of 16S rRNA gene. The DNA data revealed an unusual surge of Vibrio in sea-water contaminated with tarballs in May 2018 (16.16% OTUs), compared to tarball-free seawater samples collected in March 2018 (no detectable OTUs) and September 2018 (0.17% OTUs). Further studies are required to investigate if Vibrio species form biofilms on tarballs which may act as good reservoirs for their survival and transmission success.