The mysterious microbes living deep inside the earth -- and how they could help humanity | K. Lloyd

Microbial Life Beneath Our Feet

The Hidden World of Subsurface Microbes

• The earth beneath us is not solid; it contains numerous fractures and empty spaces filled with vast quantities of microbes.

• Microbes have been found as deep as five kilometers below the surface, illustrating their extensive presence in the earth's crust.

• While gut microbiomes weigh about 100,000 tons collectively, microbes on the earth's surface total around two billion tons. However, subsurface microbes outweigh them at approximately 40 billion tons.

• This significant biome was largely unknown until recent decades, suggesting limitless possibilities for understanding life and its potential benefits to humans.

Sampling Challenges and Microbial Activity

• A map shows limited sampling locations for subsurface microbes; if we relied solely on these samples, we would struggle to reconstruct a global microbial map.

• Critics question whether these subsurface microbes are merely dormant. Compared to other organisms, they may appear inactive due to their slow growth rates.

• If all subsurface microbes divided rapidly like E. coli, they could double the weight of the Earth overnight. Many may not have divided since ancient times.

Understanding Longevity Through Analogy

• An analogy compares understanding long-lived organisms (like trees) from a short human lifespan perspective—suggesting that our perception of microbial dormancy might be flawed.

• Just as trees wait for summer to thrive while humans live only a day, deep subsurface microbes might be waiting for conditions favorable for activity.

Survival Strategies of Subsurface Microbes

• Some surviving E. coli cells can outcompete faster-growing cultures under starvation conditions, indicating an evolutionary advantage to being slow-growing.

• Two primary survival strategies exist: some microbes rely on nutrients trickling down from above while others thrive independently within the earth.

Energy Sources in Subsurface Ecosystems

• In contrast to surface plants that utilize sunlight for energy production through photosynthesis, subsurface ecosystems must find alternative energy sources.

Understanding the Interplay of Microbes and Geology

The Role of Chemolithoautotrophs

• Microbes, specifically chemolithoautotrophs, derive energy from rocks and produce minerals as waste products, such as rust and limestone. This process highlights their dual role in both biological and geological contexts.

Exploring Volcanoes and Subduction Zones

• The speaker emphasizes the connection between biology and geology by discussing microbes that behave like rocks. They express a desire to study volcanoes, particularly those formed at subduction zones where oceanic plates interact with continental plates.

• Subduction zones serve as gateways to the Earth's interior, allowing for material exchange between surface environments and deeper geological layers through processes similar to wringing out a wet washcloth.

Research in Costa Rica's Volcanoes

• The speaker shares an invitation to study volcanoes in Costa Rica, which is situated on a significant subduction zone. Their research aims to understand why carbon dioxide emissions are localized at volcanoes rather than distributed throughout the entire subduction zone.

• A personal anecdote reveals the hazardous environment inside Poás Volcano, where they measured extreme acidity levels while contemplating potential eruption scenarios with colleagues.

Eruption Events and Carbon Dioxide Emissions

• Humorously reflecting on safety during volcanic activity, the speaker recounts how shortly after their visit, Poás Volcano experienced its largest eruption in over 60 years. This event underscores the importance of monitoring volcanic activity for understanding gas emissions.

• The eruption illustrates that volcanoes are critical points for carbon dioxide release from oceanic tectonic plates.

Investigating Hot Springs and Carbon Filtration

• In addition to studying eruptions, researchers explored hot springs believed to be connected to deep oceanic plates. They hypothesized that carbon dioxide should also emerge but was being filtered out by underground processes.

• Scientific discoveries often occur away from glamorous settings; instead, they arise from extensive data analysis and troubleshooting efforts over time.

Discoveries About Carbon Storage

• After two years of research, findings revealed substantial amounts of carbon dioxide were trapped underground due to microbial activity converting it into carbonate minerals—indicating a natural mechanism for carbon storage.

• This discovery raises questions about whether these subsurface processes could help mitigate atmospheric carbon dioxide levels resulting from human activities.

Implications for Climate Change Mitigation

• As humans contribute significantly to atmospheric CO2 levels, understanding how subsurface microbes can sequester this gas becomes crucial for climate change solutions.

• Ongoing studies aim to determine if these slow-moving microbes will hinder or assist in storing captured CO2 effectively within geological formations.

Future Directions in Geo-Bio-Chemistry Research

Exploring the Deep Subsurface World

Potential Applications of Research

• The research aims to discover new products beneficial for industrial and medical applications, highlighting the practical implications of understanding subsurface environments.

• There is a potential for this research to contribute to predicting natural disasters such as earthquakes, showcasing its relevance in disaster preparedness and risk management.

• The exploration may extend to astrobiology, including searching for extraterrestrial life, indicating a broad scope that transcends Earth-centric studies.

• Understanding the origin of life itself is another significant goal, suggesting that insights gained could reshape our comprehension of biological evolution and existence.