15 January 2009

img_0830 I know, I know, huge methane plumes on Mars (!!!) it’s hard to keep one’s head on straight.  I feel a bit woozy myself.  But I really expect more from the New York Times than this:

Bacteria May Be Source of Methane on Mars — Kenneth Chang 1/15/2009

Normally when I see a headline like that, I assume the headline writer has been hitting the black label a little to hard again.  Unfortunately, that’s not the case this time here’s the second sentence in that article:

Subsurface Martian cows appear unlikely, but scientists are seriously considering the possibility that bacteria are generating the methane.

Well, first off, of course cow emissions are bacterially* generated, but whatever.  Even *if* the Martian methane is of biological origin (and don’t forget there is loads of abiotic methane elsewhere in the solar system) it’s a tremendous leap to attribute the methane production to bacteria.  “Bacteria” is not a generic term for microbes, it refers to a specific group of unicellular organisms that have been on Earth for billions of years.

The discovery of bacteria on Mars would have tremendous implications for the interplanetary dispersal of organisms and possibly even for the origin of life itself.  But the presence of methane alone does not yet confirm the presence of life on Mars and it certainly doesn’t indicate that any hypothetical Martian microbes had a common origin with life on Earth as the presence of bacteria would.  Lets wait for some more facts before we start making a interplanetary leaps to conclusions, please!

POSTSCRIPTO: *It occurred to me that actually methanogens (microbes that generate methane) aren’t even technically bacteria–they’re archaea! Any speculation that bacteria are responsible for the methane plumes on Mars is basically totally without merit. I’m sure we’ll see a retraction in the Times tomorrow.


3 Responses to “O RLLY?”

  1. Jeremy Says:

    So you’re saying they ought to consider possible methanogens residing inside owls, beneath the surface of mars?

    what makes them think methane is being synthesized rather than just working its way out of mars? ah, i’m now reading that they don’t know where else it would come from since they believe there ~isn’t~ some requisite geological cause and the clouds now being detected would have dispersed.
    Neil, is it your guess that this is likely to end up a lesson in unsensational ways of accounting for the presence of methane?

    If the explanation does wind up biological, what’s your response to talk of common origins?
    (i’m wondering if the following could relate to your thinking. standing back a moment I chuckle knowing it’d be up to you to make it fit 🙂
    …the appearance of martian sand, spread out in a fan like distribution from sliding down hill, does this have common origins with similar earthly deposits? (granted, an event, sliding earth tends to resolve the possibility of further downhill dispersal rather than being an occurrence whose happening is given to reproducing itself)
    so neil, are you weighing the probabilities of interplanetary transfer vs local martian origination of Methanogens and concluding the latter is more likely since their structure is simple enough it can develop in mundane enough conditions (albeit not as commonly as land slides can be expected on planets in the universe)

    As for bacteria, you’re saying proposing this is analogous to asking if an egg “come from that rooster?” when you’re pointing at a hen?

    Are you seeing the Meat Puppets in Petaluma at McNear’s Mystic Theatre, Sunday?

  2. Neil Says:

    Sadly, I’m lately too poor for shows…though Petaluma would probably be a fun place to see the Meat Puppets.

    I’m personally agnostic re: abiotic/v. biotic origin for the methane. Every time we scrutinize a planetary body beyond Earth we come away surprised by what is going on there geophysically. I haven’t seen any compelling reason to argue that a biotic origin for the mehane is more likely simply because we lack a good abiotic explanation at this point.

    Unfortunately, we really lack any framework to evaluate the relative probability of microbial dispersal between Earth and Mars vs. independent evolution on each planet. But first we need to establish whether the methane is truly of biological origin, then we can address the question of relationship (or lack thereof) to life on Earth, if we are lucky enough to get living or fossil samples from Mars.

    Really my point is that it’s irresponsible to use the term “bacteria” or even “archaea” when you really mean “microbe.” It might seem like a trivial distinction but irresponsible use of language by scientists can cause tremendous confusion especially when the science is so high profile.

  3. arvind Says:

    Heh. The hype was exciting for a day! Anything to get a little extra coverage for the scientific enterprise

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