Tyndmyr wrote:Additionally, the nutrients in the sub-solar regions largely consist of what sinks down from the areas where solar energy drives the ecosystem. Removing the sun from the ecology does pose significant energy concerns, which is particularly troublesome when you are proposing a particularly massive concentration of biomass.
In short, this example does not support your claim, and actually would appear to subvert it.
Check your facts, brother!
From wiki: "Previously, benthic oceanographers assumed that vent organisms were dependent on marine snow, as deep-sea organisms are. This would leave them dependent on plant life and thus the sun. Some hydrothermal vent organisms do consume this "rain", but with only such a system, life forms would be very sparse. Compared to the surrounding sea floor, however, hydrothermal vent zones have a density of organisms 10,000 to 100,000 times greater."
So we're six orders of magnitude from "desert". Granted, this is only in tectonically active regions, but as Gmalivuk helpfully pointed out, tidal flexing effects dwarf any radiogenic potential and practically guarantee a core that's covered in such vent zones.
"desert" is a relative term, not an absolute one. This does not immediately get you to "megasystems distributed across the ice". Such communities are extremely localized, and the zone as a whole IS mostly reliant on this "rain", and is very, very sparsely populated on average, even with vent systems included.
Even assuming that vent systems are common(which may be the case), and that they exude a similar proportion of usable nutrients, etc(which may not be the case), getting from there to a massive ecosystem causing ice fractures requires an entire chain of life that isn't really at all analogous to earth's, so you're kind of out in the weeds. It's a LOT of assumptions without evidence.
JudeMorrigan wrote:As large as it would be, we'd be able to get spectral results off the "roots" themselves.
Please, enlighten me! What spectral results are you expecting that we don't see? You're clearly far better-versed than I in the EM spectra of inhabited vs uninhabited water-ice moons. We observe sulfur salts, which we well know extremophilic bacteria use in redox. Does your Scouter not get a power level reading?
Sulfur salts are great, as is water, but while both open up possibilities of life, they are not proof of life. We have precisely one known case of life, Earth, and the spectral analysis for that indicates obviously, a lot of O2, H2O, etc. I expect that in general, the more a given set of spectral results looks like earth's, the stronger case you'd have...though it'd still be fairly weak, because as mentioned, merely having water, etc doesn't guarantee life. We already know of a number of bodies containing water on which we have not found life. If life was as plentiful everywhere there was water as on earth, it seems probable we'd have found it by now, but we haven't.
Anyway, if we narrow it down from "finding life via spectral results" to "confirming THIS particular theory via spectral results", that makes the task somewhat easier, because you're proposing an immense ecosystem. Such an ecosystem, of necessity, would need a truly massive sulfur cycle, and you would expect to see evidence of large quantities of the various compounds we see in proportions roughly akin to earths. What we know of the atmosphere on Europa indicates that it's quite thin, and mostly made up of O2. That isn't really evidence of a vast sulfur-based ecosystem. Granted, our current evidence is limited, and I guess it's possible that somehow a vast system exists, but does not affect the atmosphere, but what we know does not provide support for your idea. Now, this sort of life might exist in a much smaller form, it's the whole vast ice-cracking ecology that I'm having trouble with.
Note: I am less qualified in this area than Jude, as my astronomy experience consists of "hey, those look like fun electives" in college. Still, I wrote up my response before I noticed his, so hell with it, I'm posting it.