Questions about Hydrogen

November 13:

What mechanisms could transport hydrogen from a theorized deep source to the level of the second biosphere? Consider fissions/fractures, rates of diffusion, advection, what else?

If hydrogen production is occurring as theorized by Freund et al, and has been since the beginning of the earth, then what sort of evidence would we expect to see today?  

Is anhydrous-rock hydrogen production a sustainable enough mechanism to support a continuous community of microbes?

October 30:

What are the limiting nutrients in these deep subsurface environments?

How continuous/heterogeneous is the “second biosphere”?  How deep is it, and does it have limits? What is its volume?

Can deep subsurface communities support eukaryotes?

Could we compute a mass balance/budget for hydrogen formation based on the available evidence? 

October 9, 2003

When would energetics favor methanogenesis over acetogenesis (or other
processes)?

Where does subsurface hydrogen come from?

How much hydrogen could be produced/solubilized in a particular
setting/pressure?

What technologies are appropriate for studying hydrogen in the deep
subsurface, and what limitations need to be considered?

How different are surface and subsurface microorganisms, and what role does
contamination play in blurring the distinction?

What does the study of hydrogen utilization tell us about the possibility of
hydrogen-dependent communities independent of photosynthesis? Are there any
other uses for studying hydrogen-based communities?