Date of Graduation

5-2025

Document Type

Thesis

Degree Name

Bachelor of Science in Biology

Degree Level

Undergraduate

Department

Biological Sciences

Advisor/Mentor

Kral, Timothy

Committee Member

Paul, Katheleen

Second Committee Member

Ivey, Mack

Third Committee Member

Dowdle, Andrew

Abstract

The search for life beyond Earth has been the motivating factor for many scientist’s research in the past and currently. Specifically, the efforts have largely been focused on Mars. Mars exhibits qualities that are similar to the life-harboring characteristics of Earth, creating the possibility for life to exist on Mars. Mars’ subsurface conditions may be ideal for specific microorganisms to thrive, providing a haven away from the harsh surface conditions (Mancinelli, 2000). It is known that one of the most important elements to support life, H2O is found in the subsurface of Mars, along with an atmosphere lacking oxygen, and an atmosphere with a trace of methane (Wray, 2021). Microorganisms belonging to the domain Archaea are ideal candidates for an extreme environment like Mars, specifically methanogens. These organisms are anaerobic, typically using hydrogen to fuel growth through methanogenesis, releasing methane as a byproduct of metabolism. Methanogens offer a solution for the methane found on Mars. The survivability of methanogens in Martian conditions has been studied in Dr. Kral’s laboratory demonstrating their ability to survive using limited nutrients (Kral, et al., 2004).

This research project observed the growth of Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, and Methanococcus maripaludis using pyrite as an energy source to fuel metabolism. Methane is a product of methanogenesis, allowing for growth to be monitored through methane output. The four species were each prepared in the most basic media, MM, and incubated in their ideal growth conditions. Two of the four methanogens showed growth using pyrite as an energy source, M. formicicum and M. barkeri. The two that showed zero growth were M. maripaludis and M. wolfeii. Further experimentation was done regarding the sterilization of pyrite and its effects on growth.

Keywords

Methanogens; Pyrite; Mars

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