Exploring Microbial Populations Across the Three Domains of Life in Hot Springs at Lassen Volcanic National Park

Abstract

Lassen Volcanic National Park (LVNP) is composed of a variety of environments such as acid-sulfate, and chloride-rich hot springs, fumaroles, and mud pots. This variation in geochemistry may host a high diversity of micro-organisms within LVNP, which can inform about life on a deoxygenated early Earth, past extraterrestrial life on Mars, and further knowledge of bioactive compounds. However, research on microbial communities in hydrothermally active environments at Lassen Volcanic National Park is limited, especially on the microbial eukaryote inhabitants. To address this, Illumina sequencing of PCR amplicons of the V4V5 region of 16S rRNA and V8V9 region of 18S rRNA genes were conducted with samples collected from five main sites at LVNP in August 2017. In this study, I characterized microbial community structure and diversity for Bacteria, Archaea and Eukaryotes in hot springs, fumaroles, and stream water at LVNP and considered that data in context with available environmental parameters. The acidothermophilic sites were dominated by sulfur reducers and oxidizers, along with iron oxidizers, from the class of Thermoprotei. The order, Burkholderiales of the Gammaproteobacteria, was also prominent at each location. The near-neutral sites were dominated by bacteria of the Cyanobacteriia class within biofilm samples. The eukaryotic micro-organisms in both the near-neutral and acidic sites were dominated by Ascomycota from the genus of Penicillium, which is important industrially for the production of cheese and antibiotics. Diversity in prokaryotic communities were higher than eukaryotic communities, which may indicate differences in their responses due to the variation in metabolic capabilities in their extreme environments. These results contribute understanding of how the environmental drivers of the acidic and neutral hot springs influences microbial distributions across all three domains of life.