Cool research.
Aherm
Mine's the one with "Snow business like show business" in the pocket.
The ice sheets and glaciers that extend over roughly 11 per cent of the Earth’s land mass are home to a surprisingly abundant source of life. Sections of liquid water beneath and inside the ice provide a habitat for a genetically diverse variety of microbes. And studying these organisms gives us some clue what life may have …
Indeed, the possible implications for life on other planets is one of the motivations for studying terrestrial microbial life in environments the we humans would find extreme.
Deep sea vents, arsenic-rich lakes (though it turns out that a bacterium can't substitute arsenic for phosphorus after all, as was originally reported), glaciers etc
where (IIRC) the longest spontaneous formation of chains of RNA (~100bases?) where formed at -18c.
It may even be that life was formed in the ice slush in a bay where the massive early tides ground the ice and rock into a pulp around a smoker.
Life could survive in sub-glacial lakes but not photosynthetic species. We know that cyanobacteria produced oxygen long before the global glaciations. In fact, the oxygen concentrations increased shortly after the "snowball" episodes. There is no light under hundreds of meters of ice so something is deeply wrong with this new hypothesis. I would rather bet volcanoes sticking through the ice provided heat for surface lakes or lagoons to exist during the global glaciation.
All the bits together actually do compute, and this sparking theorydoes fit a couple of the holes with regards to "how did stuff survive/get nutrients" . Especially since silt particles are *still* extremely important for quite a number of (semi)catalytic reactions that , amongst others, make the difference between "good" and "poor" soil.
Incidentally, all cyanobacteria are quite capable of surviving without a shred of sunlight. They have a Sulfur-based anaerobic chemotrophic backup. So any sulfur rich environment will do them just fine. Which young Earth certainly would have provided. Between the thinner crust, and the rather stronger tidal forces from a Moon in a much closer orbit, volcanoes would have been a dime a dozen, covered under ice or not. Those cyanobacteria would have been quite happy under the ice..
Why do you think it is a mono-culture?
The second sentence of the article is "Sections of liquid water beneath and inside the ice provide a habitat for a genetically diverse variety of microbes." and contains a hyperlink in blue to an abstract:
"Molecular evidence for an active endogenous microbiome beneath glacial ice.
Here, using RNA-based approaches, we demonstrate the presence of active and endogenous archaeal, bacterial and eukaryal assemblages in cold (0-1 °C) subglacial sediments sampled from Robertson Glacier, Alberta, Canada.
The article, at least as reproduced in El Reg, explains how microbes might survive. But the two most recent episodes of snowball earth were at 700 my ago and 600 my ago. By then life had evolved to algae and to animals with no shells or bones.
These relatively evolved life forms would probably need something like the volcanic havens suggested in a previous comment.
Well the first thing that comes to mind are sponges, or at least: organisms with the same basic cooperative setup, which can still function as individual cells when needed. And yes, they'd need "volcanic havens" , but those would have been pretty common. Given that ice is a pretty good insulator, those "havens" wouldn't have been small either.