2019 Schlanger Fellow – Kelli Mullane

Kelli Mullane

Scripps Institution of Oceanography


Investigating the Piezophilic Microbial Communities of Mariana Forearc Serpentinite Mud Volcanoes



Despite the significant impact that high hydrostatic pressure has on deep-sea microbial communities, little is known about the role it plays within the deep subsurface biosphere. This includes the serpentinite mud volcanoes of the Mariana forearc (which characteristically have high pH and high concentrations of methane, hydrogen, formate, and acetate), a possible habitat for the origin of life. This study aims to assess deep subsurface piezophilic (pressure- loving) microbial communities present within the serpentinite mud volcanoes of the Mariana forearc – which were drilled during International Ocean Discovery Program (IODP) Expedition 366. Metagenomics, single-cell genomics, and metatranscriptomics will be employed to determine the community composition of the high-pressure adapted microorganisms present within these systems, as well as their functional potential within this environment. Comparison of metatranscriptomes of replicate microcosms incubated at various pressures will reveal, on a community level, genes important for adaptation to high hydrostatic pressure. This work will shed light on the role pressure plays within the deep biosphere and provide further insight into adaptations to environmental conditions present on the early Earth and which also exist elsewhere in the solar system.




As an undergraduate at Rutgers University, it was my work on hydrothermal vent microbial communities that sparked my interest in the study of extremophilic microbes. Now pursuing a Ph.D. in Marine Biology at the Scripps Institution of Oceanography, my research focuses on microbial adaptation to extreme environments – particularly high pressure and high pH systems. I utilize coupled molecular and physiological approaches to understand how microbes adapt to survive at the limits of life, and how these adaptations may be relevant to the origin of life on Earth and elsewhere in our solar system. The Schlanger Fellowship allows me to investigate the extremophilic microbial communities in a region hypothesized as a possible location for the origin of life on Earth, the Mariana Forearc serpentinite mud volcanoes.