I'm willing to argue that the cutest thing you're
going to see all week is the tardigrade.
Every day, NASA posts an astronomy picture of the day.
And if you're not following it, you
should be because every day you could
be getting awesome pictures of stars and galaxies and planets
and, last week, a tardigrade.
Oh.
So Popsci picked up this picture, and before I knew it,
I was lost in a sea of Google Images of tardigrades,
and I decided that I just had to talk about them.
Now I need to get over the cuddly, adorable factor
for just a second so that I can talk about these really
awesome polyextremophiles.
Also known as water bears, these little guys,
most only 1/4 to 1/2 millimeter long are plentiful.
And there are over 700 known species
which can be found in both salt and freshwater.
They like to live in moss or at the bottoms of lakes.
And they spend much of their time munching
on bacteria and plant life.
Now, I love this description of them
from a 2002 issue of Cell Biology--
"Under a microscope, a tardigrade
looks a lot like a c. elegans in which someone has deviously
expressed drosophila leg genes."
That is the most scientisty way of saying that something looks
like a chubby worm with legs.
Now I mentioned before that tardigrades
are polyextremophiles.
And what I mean by this is that they
can withstand many extreme conditions--
extreme heat, extreme cold, extreme pressures, freezing,
radiation, and even dehydration.
They've been found in boiling hot springs
and under layers of Himalayan ice.
They can withstand temperatures from negative 328 degrees
Fahrenheit to 300 degrees Fahrenheit.
And they can withstand pressures 6,000 times that of the Earth's
atmosphere.
And they can withstand about 1,000 times the amount
of radiation that would kill a human.
Tardigrades are such bamphs, that they can withstand space.
And I don't mean in tiny little tardigrade astronaut suits.
I mean they can be out there with nothing,
in the solar wind, subzero temperatures, and vacuum
of space.
In 2007, dehydrated tardigrades were exposed
to outer space for 10 days--
10 days-- and when they came back down to earth and were
rehydrated, not only did some of them survive,
but they went on to reproduce--
bamphs.
So how do tardigrades do it?
Why are they so good at surviving?
And what can we learn from it?
So it seems that most of their survivalist skills
come from their ability to dehydrate.
When stressed, they can curl up into tiny balls known as tuns.
And they can drop their metabolic activity
to about point 0.01% of normal--
practically nothing.
The tardigrades also produce a sugar
known as trehalose which helps to protect
their cells, organelles, and membranes by suspending
everything in a gel-like medium.
Tardigrades have been shown to stay in that dehydrated state
for up to 10 years.
But when reintroduced to water and favorable conditions,
they can rehydrate and be back to normal
in just a couple of minutes.
This dehydrated state is known as anhydrobiosis.
And along with cryobiosis, the state in which the tardigrade
can withstand freezing, it falls under the broad category
of dormancies known as cryptobiosis.
Scientists hope to one day take the lessons
that they learn from tardigrade stress response
to develop techniques to help other organisms,
including humans, deal with extreme conditions.
Now about a month ago, I tweeted this.
And a couple of you replied that there are actually people
making stuffed tardigrades.
And I mean, if you know someone with a birthday coming up
and you were thinking of what to get them,
I think a stuffed tardigrade--
perfect present.
Now, someone also responded with a link
to this video of a tardigrade swimming in time
to "Shut Up and Let Me Go" by the Ting Tings.
And guys, if you're having a bad day,
just go click on that video because it's
awesome and almost as good as swimming sloth videos--
almost.
Go Forth.
Do science.
All right.
Now, this video is about to take a sharp right turn
into historical storytelling.
So hold onto your pipettes and your ear buds.
Now anhydrobiosis is not something
that we have recently discovered.
In fact, it's first recorded observation
was in 1702 by Anton van Leeuwenhoek.
Now, if his name sounds familiar,
that's because he's often referred to as
the father of microbiology.
And he made great strides in improving the microscope
and was the first person to describe
single-celled organisms.
Now, he called these little guys animalcules.
And at the age of 70, he wrote a letter
to the Royal Society entitled, "On Certain Animalcules Found
in the Sediments in Gutters of the Roofs of Houses."
Now, I'm actually going to read you a little bit of what
he wrote because I feel like paraphrasing
Leeuwenhoek would be a crime.
"I have often placed the animalcules
I have before described out of the water,
not leaving the quantity of a grain of sand adjoining
to them, in order to see whether, when
all the water about them was evaporated
and they were exposed to air, their bodies would burst,
as I had often seen in other animalcules.
But now I found that when almost all the water was evaporated
so that the creature could no longer be covered with water,
nor move itself as usual, it then
contracted itself into an oval figure
and in that state remained.
Nor could I perceive that the moisture evaporated
from its body, for it preserved its oval and round
shape unhurt.
In order to more fully satisfy myself in this respect,
on the 3rd of September, about 7 in the morning,
I took some of this dry sediment, which I had taken out
of the leaden gutter and had stood almost two
days in my study and put a little of it
into two separate glass tubes, wherein
I poured some rainwater which had been boiled and afterwards
cooled.
As soon as I poured on the water,
I stirred the whole about that the sediment which,
by means of the hairs in it seemed
to adhere like a solid body, might the sooner
be mixed with the water.
And when it had settled to the bottom of the glass,
I examined it and perceived some of the animalcules lying
closely heaped together.
In a short time afterwards, they began to extend their bodies.
And in half an hour, at least a hundred of them
were swimming about the glass, though the whole
of the sediment which I had put into it
did not, in my judgment, exceed the weight of two grains.
The preceding kinds of experiment I
had many times repeated with the same success.
And in particular, with some of this sediment which
had been kept in my study about five months,
and upon pouring on it rainwater which
had been boiled and afterwards cooled, I saw in a few hours
time many of the animalcules before described.
And if, after being so long in a dry state, these animalcules
upon water being given to them can unfold their bodies
and move about in the usual manner,
we may conclude that in many places, where
in summertime the waters stagnate and at length dry up,
there may be many kinds of animalcules which,
though not originally in those waters,
may be carried thither by waterfowl in the water or mud
adhering to their feet or feathers."
Now, that letter is over 300 years old.
And that moment of observed discovery
is still so cool to me today.
And it's so cool that we can read that
and read his original words and experience
that excitement with him.
Now, it's most likely that the animals that Leeuwenhoek saw
were rotifers.
But it is also possible that his samples contained protozoa,
nematodes, and tardigrades.