Set phasers on stunning: An animal that can survive in space

This is not, sensu stricto, a post about aging, but what can I say? Tardigrades! I love these little guys. Plus it’s Friday.

Last year we learned that organisms of the phylum Tardigrada (the so-called “water bears,” most closely related to arthropods) are unusually resistant to physiological stress. Given the well-established relationship between long lifespans and resistance to (most) stresses, I had wondered why tardigrades are not also unusually long-lived. (They can persist for years in a dormant state, but their fully animated lifespans are on the order of months.)

Now, Jönsson et al. reveals that tardigrades can survive unshielded in outer space:

Tardigrades survive exposure to space in low Earth orbit

Vacuum (imposing extreme dehydration) and solar/galactic cosmic radiation prevent survival of most organisms in space. Only anhydrobiotic organisms, which have evolved adaptations to survive more or less complete desiccation, have a potential to survive space vacuum, and few organisms can stand the unfiltered solar radiation in space. Tardigrades, commonly known as water-bears, are among the most desiccation and radiation-tolerant animals and have been shown to survive extreme levels of ionizing radiation. Here, we show that tardigrades are also able to survive space vacuum without loss in survival, and that some specimens even recovered after combined exposure to space vacuum and solar radiation. These results add the first animal to the exclusive and short list of organisms that have survived such exposure.

Which is pretty cool, when you think about it.

Still, as an adherent of the “stress resistance = longevity” school, I am nagged by the question: If tardigrades can survive hard vacuum, ultra-low temperatures, blazing radiation and Klingon disruptors, what on Earth (or off it, for that matter) is going on inside their cells that does them in after a few short months of life?

Advertisements

4 comments

  1. Chris,

    An excellent question. Something at the level of gene expression must be providing an insulating, protective effect.

    I have also always been enamored by tardigrades since Dr Bruce Secker, my HS biology teacher in the mid 70’s who did his PhD work on them introduced them to us. Fascinating little boogers.

    Perhaps we should stick one on an asteroid and see what happens?

  2. I think we should find a way to get tardigrades to fix the toilet on the ISS.

    C. Caston — great questions. Controlling for everything else (body plan, size, etc.) what is the effect of parthenogenesis on lifespan? There are multiple paths to parthenogenesis — hermaphrodite worms make their own sperm, and definitely live longer if they’re not externally mated. But there are parthenogenetic amphibians (newts, somewhere near the Great Lakes) that are parthenogenetic via another mechanism, and there are related species nearby to which one could compare them. Unfortunately the analysis might be confounded by founder effects, but it would still be worth looking at.

  3. Thanks Chris. My suspicion was that the lifespan would be shorter because parthenogenesis or hermaphroditic reproduction would be like inbreeding with your self.

    Even though they are highly resistant to stress there is still some chance of genetic damage e.g. like maybe .01% per day and the longer the lifespan the more likely it will get some genetic damage.

    When you say that the hermaphrodite worms live longer if they are not externally mated are you mean their offspring?

    I would have thought the offspring would be more heterogeneous and thus live longer.

    I also wonder why animals with such long lifespans (e.g. humans) lose their ability to regenerate limbs and heal wounds without scarring.

Comments are closed.