Project

The continental subsurface holds more bacteria and archaea than any other habitat on Earth yet the origins, eco-evolutionary dynamics and behaviors of these organisms are still largely unknown. As European policies increasingly turn towards CO₂ mitigation strategies that form new and innovative interactions with subsurface environments, there is an urgent need to understand how subsurface microorganisms respond to physical-chemical changes in natural and human-altered environments. These research questions are especially intriguing given the fact that continental subsurface environments lack the high-energy electron donors and acceptors available on Earth’s surface but can still support microorganisms that, in the most extreme cases, maintain solitary lifestyles with estimated mean generation times of hundreds to thousands of years. Thus, rapid changes in physical-chemical conditions driven by human influence, seismic activity or other environmental factors can quickly push these energy-starved microorganisms into new, nutrient- and energy-rich environments. Recently, the rapid production of hydrogen peroxide through cataclasis has gained new attention as a potential oxidant source in the pre-oxygenic photosynthesis Archaean world but the biogeochemical feedbacks associated with this process are largely unknown. To address this, we have developed an experimental program using biological and chemical monitoring and multi-omics to study microbial responses to cataclastic hydrogen, oxygen, hydrogen peroxide and reactive oxygen species production in the subsurface. Using these integrated approaches, we plan to: - Quantify the production of hydrogen, oxygen, superoxide and hydrogen peroxide during cataclasis - Evaluate microbial and viral population turnover during and after cataclasis - Identify microbial lineages that respond to physical-chemical changes caused by cataclasis - Identify differentially expressed genes during and after cataclasis - Understand the trajectory of biological and chemical species throughout field and batch cataclasis experiments - Evaluate whether surface water (and associated microbial communities) exhibit different biotic and abiotic responses to cataclasis relative to groundwater. Together, this work will undoubtedly provide new insights into the evolution and adaptations of deep subsurface organisms and provide new insights into the effects cataclasis may had on early Earth ecosystems.

Project Leader Institution

ETH Zürich

Project Contact

Cara Magnabosco

Funding

Swiss National Science Foundation