Re: I wonder if we see anything similar on Europa?

[Michael Turner]

Title: Message

One problem for cryoconoids (if I may coin a term) on the surface of Europa is the requirement of melting ice.  With Europa's received sunlight being 1/25th the intensity of sunlight on Earth, will cryoconoids, no matter how absorbent of infrared, be able to heat ice to melting temperature?  Can their bacterial metabolisms turn other wavelengths into heat efficiently enough to keep their own ambient liquid environment warm enough?  Faint signs of metabolism have been observed in subfreezing conditions, so maybe there's hope anyway.   Another problem is the gas bubble - any source of heat will also increase gas diffusion rates, and Europa's "atmosphere" is virtually a vacuum, so a bubble is likely to leak, even if it's leaking through a centimeter or more of ice.   Finally, this bug has to be pretty rad-hardened - if it's close enough to the Europan surface to get light from the sun, it's close enough to get a very serious dose from Jupiter itself.   It seems these colonies don't require a mineral particle, by the way - they've been observed on glaciers where most of the light absorption is from microbial waste products. -michael turner [EMAIL PROTECTED]   ----- Original Message ----- From: TAYLOR, MICHAEL To: [EMAIL PROTECTED] Sent: Thursday, June 10, 2004 1:56 AM Subject: RE: I wonder if we see anything similar on Europa? On possibility that would allow phototropic communities in the ice (provided they first either evolved at depth near volcanic vents or were transported to Europa from Earth via impact): cryoconites.  These are complex microbial ecosystems found within tiny bubbles in all polar and glacial ice on Earth.  What happens is a bit of dust, rock, or any dark-colored debris is embedded in the ice and absorbs heat from sunlight.  This causes localized melting, creating a small gas pocket lined with a film of liquid water.  If there are bacterial spores in the ice, they prosper.  Over time, a cryoconite community can become self-sustaining, as greater numbers of bacteria add to the overall warming of the bubble.  If even a little sunlight penetrates the ice, you have the basis for a photosynthetic food chain that (on Earth) may have involve dozens of bacterial species and even larger organisms living over many generations in an island-like ecosystem, all within a bubble a few millimeters in diameter.