[meteorite-list] Tardigrades

From: Francis Graham <francisgraham_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:23 2004
Message-ID: <20020910004821.73591.qmail_at_web40102.mail.yahoo.com>

   In a Sept. 7 e-mail to this list, Mr. Wallace wrote
of tardigrades...

>I wonder if they could survive millions of years in
>their hibernation state speeding around the solar
>system on (or in) their host meteorite (or- more than

>likely- their host comet- from really deep space).

  I have some tardigrades. The are available from
Carolina Biological Supply. They are about the size of
periods at the end of sentences, i.e., 1/4-1/10 mm or
so. When you wish to make them "come alive" just add
distilled water. When you SLOWLY dry them out they
enter a state of cryptobiosis that can be sustained
apparently indefinitely. One person is reported to
have looked for tardigrades in cryptobiotic states on
ferns pressed in colonial-era books (18th century), as
was a popular habit then. Add water, they came alive.
   They do not have much else to commend themselves as
pets except they are not dangerous and carry no human
disease I am aware of, and live in cryptobiosis for a
long, long time. They do not bite, because I put some
on my arm once to see. Well at least, they didn't bite
me.
  The hypothesis that tardigrades can travel in space
in meteorites is interesting, but tardigrades are very
much Earth creatures. It MAY be possible, not knowing
other factors, that tardigrades could be ejected in an
impact in a meteorite and return to Earth after being
in space. But it would have to survive, while in
cryptobiosis, no air pressure, cosmic rays, X-rays,
and thermal heating, radiational cooling, all which
could still kill it even when cryptobiotic. Even deep
inside a meteorite-to-be, it would seem tardigrades
would face incredible odds.
I suppose a person might try some experiments placing
tardigrades in vacuum chambers, and such, with
appropriate environmental simulation. I think there
might be a lot to learn with such experiments.
   The biological mechanism that causes cryptobiosis
would seem very interesting, can you give more info on
Diane Nelson's dissertation?

>Fun to speculate, anyway.
   It sure is fun to speculate! One might very
speculaively imagine a future science-fictiony
technology where tardigrade genes are spliced into
human genes and such bioengineered people could then
go into cryptobiosis and endure long space travel to
other solar systems. But that for now seems very
science-fiction, emphasis on fiction.

Francis Graham




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Received on Mon 09 Sep 2002 08:48:21 PM PDT