#  Professor Barbara Sherwood Lollar (University of Toronto - Department of Earth Sciences) "Insights into Habitability and Astrobiology from Exploration of Earth Analogue Environments" 

 



####  calendar\_today Date and Time 

 **February 21, 2024** 

 04:00PM - 05:30PM EST 

####  pin\_drop Location 

 **Haller Hall, 24 Oxford Street**  



 

 



 

 For more information about Professor Lollar, please see her [website. ](https://www.es.utoronto.ca/people/faculty/sherwood-lollar-barbara/)

 Abstract:

 Insights into Habitability and Astrobiology from Exploration

 of Earth Analogue Environments  
Barbara Sherwood Lollar

 Dept of Earth Sciences, University of Toronto, ON, M5S 3B1, CA and Institut de Physique du  
Globe de Paris (IPGP), Université Paris Cité, 1 rue Jussieu, 75005, Paris, France  
<barbara.sherwoodlollar@utoronto.ca>  
Over the past few decades, first on the deep ocean floor, and then expanding to the  
continental lithosphere, Earth analogue studies have revealed previously unexplored  
localities and unexpected processes, together challenging us to think more broadly and  
universally about the fundamentals of habitability. Scientists investigating microbial  
communities identified water-rock chemical reactions such as serpentinization and  
radiolysis that produce critical electron donors (e.g. hydrogen) and electron acceptors (e.g.  
sulfate) capable of sustaining chemolithotrophic microbial communities in the oceanic and  
terrestrial crust. Such processes of water-rock reaction have now been shown to be a major  
driver hydrogen and sulfur cycles in the subsurface of the planet, and increasingly their role  
in the deep carbon cycle is being investigated.  
Subsurface “rock-eating” microbial communities have been shown to be sustained  
on long time scales, isolated from the surface hydrologic cycle. Both field and laboratory  
discoveries are expanding the spectrum of water-rock reactions that drive the H, S and C  
deep cycles and provide mechanisms for sustaining deep subsurface life in the absence of  
interaction with a surface photosphere. Discussions of habitability typically focus on the  
necessity for fluid mixing and/or spatial geochemical gradients, but recent discoveries  
suggests apparently thermally and spatially “stagnant” systems may still be habitable  
through radiolysis. New insights from terrestrial analogue sites suggest potential models for  
planetary habitability capable of sustaining chemolithotrophic life on bodies where  
photosynthesis may never have arisen. These terrestrial discoveries have catalysed an  
expanded search for habitable environments on planets, exoplanets and moons to include  
not only surface based life but potentially subsurface biospheres.



 

 



 

 See also:- [ Forums ](/events/forums)
 
 

 Share on:- [     Facebook ](#)
- [     Twitter ](#)
- [     Linkedin ](#)
 


 Save: [ Add to calendar calendar\_today ](https://origins.harvard.edu/node/1537711/event-feed.ics)  Copy link link