After reading the latest issue of New Scientist, I think I may leave instructions to freeze my head when I die. It’s not because of any terrific new cryogenics method revealed by the magazine, but because of their series of short articles on extremophile organisms. You know, the thermophiles that can survive boiling temperatures (one microbe lived through a spell of 130° C (266° F), like the North American Wood Frog (Rana sylvatica), Painted Turtle (Chrysemys picta) hatchlings, and Woolly Bear caterpillars (Pyrrharctia isabella, which turn into the Isabella Tiger Moth) that can be frozen solid or nearly so and come to life again. Then there are the ones that can survive being dried out by “replac[ing] water molecules [in and around the cell] with sugar, turning their cytoplasm into a solid called sugar glass”. (New Scientist, 13 Nov 2010, p. 41). These are mostly small invertebrates. One in particular takes the survival prize: the tardigrade or water bear.
Microphotograph of tardigrade or water bear, in the phylum Tardigrada, part of the superphylum Ecdysozoa. They are microscopic, water-dwelling, segmented animals with eight legs. Unlike lots of microscopic animals, they do not seem to live by choice on or in humans, so you can study the photo without getting itchy. Photo source.
Because it is directly related to why I might want to freeze my head, let me quote from Wikipedia’s article on the tardigrade’s survival feats:
More than 1,000 species of tardigrades have been described. Tardigrades occur over the entire world, from the high Himalayas (above 6,000 metres (20,000 ft), to the deep sea (below 4,000 m) and from the polar regions to the equator.
The most convenient place to find tardigrades is on lichens and mosses. Other environments are dunes, beaches, soil, and marine or freshwater sediments, where they may occur quite frequently (up to 25,000 animals per litre). Tardigrades often can be found by soaking a piece of moss in spring water.
Tardigrades are able to survive in extreme environments that would kill almost any other animal. Some can survive temperatures of −273 °C (−459.400 °F), close to absolute zero, temperatures as high as 151 °C (304 °F), 1,000 times more radiation than other animals, and almost a decade without water. In September 2007, tardigrades were taken into low Earth orbit on the FOTON-M3 mission and for 10 days were exposed to the vacuum of space. After they were returned to Earth, it was discovered that many of them survived and laid eggs that hatched normally.
Below, a tardigrade in cryptobiosis (dried-out state) waiting for wetter conditions. Photo source.
What the tardigrade means to me
The greater likelihood of…Life on Mars!
Areologists have found evidence to support the presence of surface water on Mars in earlier times (1, 2). On Earth, the one condition life seems to require is water in the environment. It can adapt to other conditions of astonishing harshness, as the extremophiles show. Therefore, if life developed upon Mars during the time of surface water, it is quite possible it has adapted to the new conditions.
One place to look for water and surviving life forms would be in the deep chasms of Mars, including Valles Marineris which is 1,860 miles long and in places reaches five miles in depth (five times the depth of the Grand Canyon). None of our probes has landed near chasms because we haven’t designed ways to explore them robotically. This is a job for human beings, and I am extremely disappointed that it hasn’t been done yet.
When I watched Neil Armstrong step onto the moon in 1969, I felt confident that the US and other nations would build on this accomplishment in what seemed a logical progression: space station, lunar base, a manned mission to Mars. I would not have believed that, 40 years after reaching the moon, only one of these elements would be up and running. That one, the International Space Station is a testament to the dedication of a few, but it’s not the robust establishment I expected; it seems to be on a precarious footing in mechanical reliability, and in international support. The other two are as far from reality as they were in 1969—no, farther, because the momentum of the 1960s has drained away, and the world faces more serious problems than it did then. What was justifiably affordable then, may not be now.
I don’t view space exploration as a luxury, or as an activity that merely satisfies our curiosity. It has much more to offer the species than that. We cannot say what we would have learned, what technologies we would have developed, had we followed the path I expected. Perhaps we would even have reached a slightly greater degree of wisdom about ourselves and or treatment of the planet, or maybe not.
But I do know how badly I want to see some questions answered, including “What life is there on Mars?”
And if looks as if, even if I eat my vegetables and exercise diligently, I may not live long enough in the normal course of events to find this out. So, freezing my head may be the only possibility. How can I let a bunch of tardigrades hear the news about Martian life, and not hear it myself?
Notes
1 Jakosky, Bruce M. et al. Mars’ volatile and climate history. Nature 412, 237-244 (12 July 2001).
2 Bowen, TA and Hynek, BM. Mars’ climate history as inferred from valley networks on volcanoes. Lunar and Planetary Science XXXIX (2008).
Etymological Notes
Rana sylvatica
rana, from Latin rana (frog); sylvatica from Latin sylvaticus (growing in the woods, wild)
Chrysemys picta
chrysemys, from Greek chrysos (gold) and emys (freshwater tortoise”)
Pyrrharctia isabella
Pyrrharctia, from Greek pyr– (fire) and arktos (bear—the animal, also used to refer to the north; here probably alluding to the hairy caterpillar, the “wooly bear”)
isabella, a word used to denote various vague colors: greyish-yellow, sand color, pale fawn, pale cream-brown or parchment; etymology uncertain but see here.
Tardigrada
Tardigrada, from Latin tardigradus (slowly stepping), from tardus (slow) and gradior (step, walk)
Ecdysozoa
Ecdysozoa, from Greek ekdusis (a stripping off) and zoon (a living being, animal; plural zoa)
Bonus for sticking with me to the end…
There’s one caterpillar just about everybody can identify, if only because of its supposed ability to predict the severity of the winter:
The Woolly Bear, of course, and the narrow band of brown on this one indicates a very tough winter to come. Photo by Rhys Alton from flickr.
But who among us knows what the Woolly Bear looks like when he or she grows up? Like this,
the Isabella Tiger Moth (Pyrrharctia isabella), found in much of North America and Central America. The caterpillar overwinters, hence the ability to withstand freezing temperatures. The Woolly Bear has another distinction: the first insect known to self-medicate. It eats leaves from ragworts, groundsels and other plants that are rich in alkaloids, and these help rid it of parasites; infected caterpillars eat more of such leaves than uninfected ones. Yes, everything it seems has parasites; “Great fleas have little fleas upon their backs to bite ‘em, And little fleas have lesser fleas, and so ad infinitum”. And I, driven by the desire to know things, doubtless will need to know something else once my thawed-out brain has assimilated knowledge of our first manned mission to Mars.
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