Interdisciplinary Seminar: Acacia Zhao

The UNC-CH Department of Marine Sciences presents the interdisciplinary seminar of graduate student, Acacia Zhao. This event will be held on Monday, November 9th, at 12:00 pm. This event will be held ONLINE ONLY and it will be available online via Zoom (Meeting ID: 974 6573 2747).

Seminar Title: Biodiversity of Fe-oxidizing Zetaproteobacteria at the Loihi Seamount

Abstract: The Loihi Seamount is a submarine volcano that is part of the Hawaiian archipelago. Hydrothermal vents exist on the seamount and they are characterized by high concentrations of reduced iron and CO₂ in the vent fluids and thick microbial mats produced by iron-oxidizing bacteria. The oxidation of ferrous to ferric iron has very low energy yield and thus it is puzzling how this mechanism can sustain productive hydrothermal vent communities. The first cultured representatives of Fe-oxidizing Zetaproteobacteria were isolated from the Loihi Seamount. Cultivation-independent 16S rRNA analysis suggests that this group of bacteria is commonly found in microbial mats at different vent sites at Loihi. Due to difficulties in cultivation, limited functional details can be inferred from isolate genomes. Single amplified genomes (SAGs) show that there is more diversity in the uncultured marine Zetaproteobacteria than in their cultured counterparts. These uncultured Zetaproteobacteria may not be obligate iron-oxidizing chemolithotrophs like the isolates but there is surprisingly little evidence that suggests they can utilize other inorganic energy sources. Genomic insights can be used to guide isolation of novel strains and thus lead to a better understanding of the physiology of Fe-oxidizing bacteria and its connection with genetic variations. Together, these studies show that Zetaproteobacteria are diverse and abundant members of the deep-sea Fe-oxidizing communities that contribute to global carbon and iron cycling.