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UV-Resistant Micro-Organisms Discovered In the Stratosphere
junglee_iitk writes "Three new species of bacteria, which are not found on earth and highly resistant to ultraviolet radiation, have been discovered in the upper stratosphere by some Indian scientists. These bacteria, which do not match any species on earth, were found in samples collected through a balloon sent up to the stratosphere in April 2005. The payload consisted of a cryosampler containing 16 evacuated and sterilised stainless steel probes. Throughout the flight, the probes remained immersed in the liquid neon to create a 'cryopump effect.' These cylinders after collecting air samples from different heights ranging from 20 to 41 km were parachuted down and safely retrieved, it said." Here's the Indian Space Research Organisation's press release on the discovery. Adds an anonymous reader: "This paper in International Journal of Astrobiology [PDF] speculates how microorganisms reach the stratosphere."
Who knows what we'll find in the upper atmosphere of Venus. Maybe we've been looking for life in the wrong places all alon.
I checked the linked paper, from 2005, and while is presents some interesting arguments, it is not a thorough discussion of the subject.
Too many possibilities of Earth origin are rejected with the phrase "it seems unlikely", and there's no mention of the most obvious method by which the micro-organisms get there: random motion (OK, particle velocities in the atmosphere will not be truly random, but you'd still expect a few outliers with very high velocities.)
So, their conclusions may not necessarily be wrong, but they need to do a few more experiments before making a convincing argument that they're right.
(P.S. yes I am a professional Astrophysicist)
What the hell do they eat in the stratosphere? They must also be able to survive with very little water. Maybe they spend time in lower levels of the atmosphere.
These bacteria were retrieved at "different heights ranging from 20 km to 41 k".
These altitudes bracket the surface pressures on Mars, and the conditions at 41 km are quite comparable to those
on the Martian surface (full UV flux, lower atmospheric pressure).
Given that material is exchanged between the Earth and Mars, I have to wonder if these might not be Martian bacteria.
As the paper states, these micro-organisms are viable but don't respond to culturing. Which could mean they were alive but are dormant and don't respond to conditions here on earth.
Whoa, woah there buddy. Did you consider the possibility that maybe they "don't respond to culturing" because bacteria that exclusively exist in an upper atmosphere don't like being stuck to a semi-wet petri dish at 1 atmosphere of pressure? They're totally different environments. Granted, I doubt their culturing technique was honestly as crude as conventional petri dish work, but I was making a general point about it being likely a limitation of "how" they tried to culture it.
When you make the agar or whatever medium you plan to use to cultivate any microscopic critter en masse, you're inevitably going to create a selection pressure (sometimes on purpose, sometimes it's a side effect), depending on what nutrients it supplies. I've glanced at a lengthy catalogue of agars I once saw in a microbiology lab. There's a lot of types, but they need them all for different situations. Again, I have no clue how they tried to culture them, but I'm guessing stratospheric microbiology is a relatively new thing, so I wouldn't expect the culturing techniques to be as good they should be for this purpose.
On top of that, from what I understood, we can only culture a surprisingly small fraction of microorganisms anyway. Also, culturing extremophiles has always been very hard. And I'm pretty sure this one counts as an extremophile.
There are going to be plenty of terrestrial explanations for them being uncultivable which do not lend any support to them having a population outside of Earth's biosphere.