0:00:01.165,0:00:04.613
I'm an ocean microbiologist[br]at the University of Tennessee,

0:00:04.637,0:00:07.182
and I want to tell you guys[br]about some microbes

0:00:07.206,0:00:10.400
that are so strange and wonderful

0:00:10.424,0:00:14.227
that they're challenging our assumptions[br]about what life is like on Earth.

0:00:14.251,0:00:15.680
So I have a question.

0:00:15.704,0:00:18.747
Please raise your hand[br]if you've ever thought it would be cool

0:00:18.771,0:00:21.418
to go to the bottom[br]of the ocean in a submarine?

0:00:22.372,0:00:23.522
Yes.

0:00:23.546,0:00:25.722
Most of you, because[br]the oceans are so cool.

0:00:25.746,0:00:28.449
Alright, now -- please raise your hand

0:00:28.473,0:00:32.163
if the reason you raised your hand[br]to go to the bottom of the ocean

0:00:32.187,0:00:34.478
is because it would get you[br]a little bit closer

0:00:34.502,0:00:37.195
to that exciting mud that's down there.

0:00:37.219,0:00:38.227
(Laughter)

0:00:38.251,0:00:39.541
Nobody.

0:00:39.565,0:00:41.390
I'm the only one in this room.

0:00:41.414,0:00:43.400
Well, I think about this all the time.

0:00:43.424,0:00:45.689
I spend most of my waking hours

0:00:45.713,0:00:49.499
trying to determine[br]how deep we can go into the Earth

0:00:49.523,0:00:53.276
and still find something,[br]anything, that's alive,

0:00:53.300,0:00:56.396
because we still don't know[br]the answer to this very basic question

0:00:56.420,0:00:57.619
about life on Earth.

0:00:57.643,0:01:01.243
So in the 1980s, a scientist[br]named John Parkes, in the UK,

0:01:01.267,0:01:03.171
was similarly obsessed,

0:01:03.195,0:01:05.792
and he came up with a crazy idea.

0:01:05.816,0:01:11.474
He believed that there was a vast,[br]deep, and living microbial biosphere

0:01:11.498,0:01:13.093
underneath all the world's oceans

0:01:13.117,0:01:15.735
that extends hundreds of meters[br]into the seafloor,

0:01:15.759,0:01:16.910
which is cool,

0:01:16.934,0:01:20.076
but the only problem[br]is that nobody believed him,

0:01:20.100,0:01:22.863
and the reason that nobody believed him

0:01:22.887,0:01:27.067
is that ocean sediments[br]may be the most boring place on Earth.

0:01:27.091,0:01:28.177
(Laughter)

0:01:28.201,0:01:31.236
There's no sunlight, there's no oxygen,

0:01:31.260,0:01:32.799
and perhaps worst of all,

0:01:32.823,0:01:36.998
there's no fresh food deliveries[br]for literally millions of years.

0:01:37.022,0:01:38.964
You don't have to have a PhD in biology

0:01:38.988,0:01:41.623
to know that that is a bad place[br]to go looking for life.

0:01:41.647,0:01:42.654
(Laughter)

0:01:42.678,0:01:45.895
But in 2002, [Steven D'Hondt] had[br]convinced enough people

0:01:45.909,0:01:49.517
that he was on to something [br]that he actually got an expedition

0:01:49.551,0:01:53.073
on this drillship,[br]called the JOIDES Resolution.

0:01:53.097,0:01:56.177
And he ran it along with[br]Bo Barker Jørgensen of Denmark.

0:01:56.201,0:01:57.923
And so they were finally able to get

0:01:57.947,0:02:01.312
good pristine deep subsurface samples

0:02:01.336,0:02:04.149
some really without contamination[br]from surface microbes.

0:02:04.173,0:02:09.446
This drill ship is capable of drilling[br]thousands of meters underneath the ocean,

0:02:09.470,0:02:12.966
and the mud comes up in sequential cores,[br]one after the other --

0:02:12.990,0:02:15.660
long, long cores that look like this.

0:02:15.684,0:02:19.493
This is being carried by scientists[br]such as myself who go on these ships,

0:02:19.517,0:02:22.517
and we process the cores on the ships[br]and then we send them home

0:02:22.541,0:02:24.640
to our home laboratories[br]for further study.

0:02:24.664,0:02:26.141
So when John and his colleagues

0:02:26.165,0:02:29.720
got these first precious[br]deep-sea pristine samples,

0:02:29.744,0:02:31.625
they put them under the microscope,

0:02:31.649,0:02:35.758
and they saw images[br]that looked pretty much like this,

0:02:35.782,0:02:38.259
which is actually taken[br]from a more recent expedition

0:02:38.283,0:02:40.469
by my PhD student, Joy Buongiorno.

0:02:40.493,0:02:42.781
You can see the hazy stuff[br]in the background.

0:02:42.805,0:02:45.590
That's mud. That's deep-sea ocean mud,

0:02:45.614,0:02:49.601
and the bright green dots[br]stained with the green fluorescent dye

0:02:49.625,0:02:52.363
are real, living microbes.

0:02:53.173,0:02:56.203
Now I've got to tell you[br]something really tragic about microbes.

0:02:56.227,0:02:58.306
They all look the same under a microscope,

0:02:58.330,0:02:59.937
I mean, to a first approximation.

0:02:59.961,0:03:03.553
You can take the most fascinating[br]organisms in the world,

0:03:03.577,0:03:07.243
like a microbe that literally[br]breathes uranium,

0:03:07.267,0:03:09.679
and another one that makes rocket fuel,

0:03:09.703,0:03:11.259
mix them up with some ocean mud,

0:03:11.283,0:03:13.480
put them underneath a microscope,

0:03:13.504,0:03:15.315
and they're just little dots.

0:03:15.339,0:03:16.770
It's really annoying.

0:03:16.794,0:03:19.285
So we can't use their looks[br]to tell them apart.

0:03:19.309,0:03:21.469
We have to use DNA, like a fingerprint,

0:03:21.493,0:03:23.214
to say who is who.

0:03:23.238,0:03:25.500
And I'll teach you guys[br]how to do it right now.

0:03:25.524,0:03:29.540
So I made up some data, and I'm going[br]to show you some data that are not real.

0:03:29.564,0:03:31.747
This is to illustrate[br]what it would look like

0:03:31.771,0:03:35.151
if a bunch of species[br]were not related to each other at all.

0:03:35.722,0:03:38.940
So you can see each species

0:03:38.964,0:03:43.163
has a list of combinations[br]of A, G, C and T,

0:03:43.187,0:03:44.902
which are the four sub-units of DNA,

0:03:44.926,0:03:48.711
sort of randomly jumbled,[br]and nothing looks like anything else,

0:03:48.735,0:03:51.346
and these species[br]are totally unrelated to each other.

0:03:51.370,0:03:53.425
But this is what real DNA looks like,

0:03:53.449,0:03:55.900
from a gene that these species[br]happen to share.

0:03:56.477,0:03:59.465
Everything lines up nearly perfectly.

0:03:59.489,0:04:02.909
The chances of getting[br]so many of those vertical columns

0:04:02.933,0:04:06.322
where every species has a C[br]or every species has a T,

0:04:06.346,0:04:09.131
by random chance, are infinitesimal.

0:04:09.155,0:04:14.068
So we know that all those species[br]had to have had a common ancestor.

0:04:14.092,0:04:15.989
They're all relatives of each other.

0:04:16.013,0:04:17.861
So now I'll tell you who they are.

0:04:18.338,0:04:20.942
The top two are us and chimpanzees,

0:04:20.966,0:04:24.561
which y'all already knew were related,[br]because, I mean, obviously.

0:04:24.585,0:04:26.045
(Laughter)

0:04:26.069,0:04:28.847
But we're also related to things[br]that we don't look like,

0:04:28.871,0:04:33.394
like pine trees and Giardia,[br]which is that gastrointestinal disease

0:04:33.418,0:04:36.425
you can get if you don't filter[br]your water while you're hiking.

0:04:36.449,0:04:41.363
We're also related to bacteria[br]like E. coli and Clostridium difficile,

0:04:41.387,0:04:44.849
which is a horrible, opportunistic[br]pathogen that kills lots of people.

0:04:44.873,0:04:49.047
But there's of course good microbes too,[br]like Dehalococcoides ethenogenes,

0:04:49.071,0:04:51.939
which cleans up[br]our industrial waste for us.

0:04:51.963,0:04:54.702
So if I take these DNA sequences,

0:04:54.726,0:04:57.869
and then I use them, the similarities[br]and differences between them,

0:04:57.893,0:04:59.722
to make a family tree for all of us

0:04:59.746,0:05:01.611
so you can see who is closely related,

0:05:01.635,0:05:03.540
then this is what it looks like.

0:05:03.564,0:05:05.847
So you can see clearly, at a glance,

0:05:05.871,0:05:11.188
that things like us and Giardia[br]and bunnies and pine trees

0:05:11.212,0:05:12.988
are all, like, siblings,

0:05:13.012,0:05:16.092
and then the bacteria[br]are like our ancient cousins.

0:05:16.116,0:05:20.289
But we're kin to every[br]living thing on Earth.

0:05:20.313,0:05:22.781
So in my job, on a daily basis,

0:05:22.805,0:05:27.136
I get to produce scientific evidence[br]against existential loneliness.

0:05:27.160,0:05:30.024
So when we got these first DNA sequences,

0:05:30.048,0:05:34.248
from the first cruise, of pristine samples[br]from the deep subsurface,

0:05:34.272,0:05:36.121
we wanted to know where they were.

0:05:36.145,0:05:39.359
So the first thing that we discovered[br]is that they were not aliens,

0:05:39.383,0:05:42.968
because we could get their DNA to line up[br]with everything else on Earth.

0:05:42.992,0:05:46.190
But now check out where they go[br]on our tree of life.

0:05:47.468,0:05:50.570
The first thing you'll notice[br]is that there's a lot of them.

0:05:50.594,0:05:52.419
It wasn't just one little species

0:05:52.443,0:05:54.562
that managed to live[br]in this horrible place.

0:05:54.586,0:05:56.069
It's kind of a lot of things.

0:05:56.093,0:05:58.051
And the second thing that you'll notice,

0:05:58.075,0:06:02.895
hopefully, is that they're not[br]like anything we've ever seen before.

0:06:03.482,0:06:05.616
They are as different from each other

0:06:05.640,0:06:08.505
as they are from anything[br]that we've known before

0:06:08.529,0:06:10.490
as we are from pine trees.

0:06:10.514,0:06:13.695
So John Parkes was completely correct.

0:06:14.180,0:06:18.847
He, and we, had discovered[br]a completely new and highly diverse

0:06:18.871,0:06:20.841
microbial ecosystem on Earth

0:06:20.865,0:06:24.706
that no one even knew existed[br]before the 1980s.

0:06:25.159,0:06:26.692
So now we were on a roll.

0:06:26.716,0:06:31.428
The next step was to grow[br]these exotic species in a petri dish

0:06:31.452,0:06:33.622
so that we could[br]do real experiments on them

0:06:33.646,0:06:35.685
like microbiologists are supposed to do.

0:06:36.090,0:06:37.651
But no matter what we fed them,

0:06:37.675,0:06:39.238
they refused to grow.

0:06:39.825,0:06:43.832
Even now, 15 years[br]and many expeditions later,

0:06:43.856,0:06:49.260
no human has ever gotten a single one[br]of these exotic deep subsurface microbes

0:06:49.284,0:06:50.947
to grow in a petri dish.

0:06:50.971,0:06:52.657
And it's not for lack of trying.

0:06:53.185,0:06:55.161
That may sound disappointing,

0:06:55.185,0:06:56.908
but I actually find it exhilarating,

0:06:56.932,0:07:00.503
because it means there are so many[br]tantalizing unknowns to work on.

0:07:00.527,0:07:04.114
Like, my colleagues and I got[br]what we thought was a really great idea.

0:07:04.138,0:07:07.419
We were going to read their genes[br]like a recipe book,

0:07:07.443,0:07:10.920
find out what it was they wanted to eat[br]and put it in their petri dishes,

0:07:10.944,0:07:12.855
and then they would grow and be happy.

0:07:12.879,0:07:14.530
But when we looked at their genes,

0:07:14.554,0:07:18.622
it turns out that what they wanted to eat[br]was the food we were already feeding them.

0:07:18.646,0:07:20.256
So that was a total wash.

0:07:20.280,0:07:23.257
There was something else[br]that they wanted in their petri dishes

0:07:23.281,0:07:25.097
that we were just not giving them.

0:07:26.248,0:07:29.954
So by combining measurements[br]from many different places

0:07:29.978,0:07:31.136
around the world,

0:07:31.160,0:07:34.823
my colleagues at the University[br]of Southern California,

0:07:34.847,0:07:36.553
Doug LaRowe and Jan Amend,

0:07:36.577,0:07:41.280
were able to calculate that each one[br]of these deep-sea microbial cells

0:07:41.304,0:07:44.670
requires only one zeptowatt of power,

0:07:44.694,0:07:48.634
and before you get your phones out,[br]a zepto is 10 to the minus 21,

0:07:48.658,0:07:50.706
because I know I would want[br]to look that up.

0:07:50.730,0:07:52.261
Humans, on the other hand,

0:07:52.285,0:07:54.874
require about 100 watts of power.

0:07:54.898,0:07:58.409
So 100 watts is basically[br]if you take a pineapple

0:07:58.433,0:08:04.643
and drop it from about waist height[br]to the ground 881,632 times a day.

0:08:04.667,0:08:07.048
If you did that[br]and then linked it up to a turbine,

0:08:07.072,0:08:10.310
that would create enough power[br]to make me happen for a day.

0:08:11.177,0:08:13.970
A zeptowatt, if you put it[br]in similar terms,

0:08:13.994,0:08:18.077
is if you take just one grain of salt

0:08:18.101,0:08:21.719
and then you imagine[br]a tiny, tiny, little ball

0:08:21.743,0:08:25.359
that is one thousandth of the mass[br]of that one grain of salt

0:08:25.383,0:08:28.192
and then you drop it one nanometer,

0:08:28.216,0:08:32.398
which is a hundred times smaller[br]than the wavelength of visible light,

0:08:32.422,0:08:34.057
once per day.

0:08:34.773,0:08:37.971
That's all it takes[br]to make these microbes live.

0:08:38.717,0:08:44.082
That's less energy than we ever thought[br]would be capable of supporting life,

0:08:44.106,0:08:47.180
but somehow, amazingly, beautifully,

0:08:47.204,0:08:48.394
it's enough.

0:08:49.370,0:08:51.203
So if these deep-subsurface microbes

0:08:51.227,0:08:54.779
have a very different relationship[br]with energy than we previously thought,

0:08:54.803,0:08:56.767
then it follows that they'll have to have

0:08:56.791,0:08:58.948
a different relationship[br]with time as well,

0:08:58.972,0:09:02.067
because when you live[br]on such tiny energy gradients,

0:09:02.091,0:09:03.786
rapid growth is impossible.

0:09:03.810,0:09:06.827
If these things wanted[br]to colonize our throats and make us sick,

0:09:06.851,0:09:09.471
they would get muscled out[br]by fast-growing streptococcus

0:09:09.495,0:09:11.656
before they could even[br]initiate cell division.

0:09:11.680,0:09:14.442
So that's why we never[br]find them in our throats.

0:09:15.537,0:09:19.712
Perhaps the fact that the deep[br]subsurface is so boring

0:09:19.736,0:09:22.226
is actually an asset to these microbes.

0:09:22.250,0:09:24.338
They never get washed out by a storm.

0:09:24.362,0:09:26.527
They never get overgrown by weeds.

0:09:27.125,0:09:30.321
All they have to do is exist.

0:09:30.807,0:09:34.817
Maybe that thing that we were missing[br]in our petri dishes

0:09:34.841,0:09:36.562
was not food at all.

0:09:36.586,0:09:38.064
Maybe it wasn't a chemical.

0:09:38.088,0:09:39.914
Maybe the thing that they really want,

0:09:39.938,0:09:42.770
the nutrient that they want, is time.

0:09:44.095,0:09:47.671
But time is the one thing[br]that I'll never be able to give them.

0:09:47.695,0:09:50.909
So even if I have a cell culture[br]that I pass to my PhD students,

0:09:50.933,0:09:53.424
who pass it to their[br]PhD students, and so on,

0:09:53.448,0:09:56.016
we'd have to do that[br]for thousands of years

0:09:56.040,0:09:59.271
in order to mimic the exact conditions[br]of the deep subsurface,

0:09:59.295,0:10:01.614
all without growing any contaminants.

0:10:01.638,0:10:02.936
It's just not possible.

0:10:03.637,0:10:06.763
But maybe in a way we already have[br]grown them in our petri dishes.

0:10:06.787,0:10:09.597
Maybe they looked at all that food[br]we offered them and said,

0:10:09.621,0:10:11.483
"Thanks, I'm going to speed up so much

0:10:11.507,0:10:13.747
that I'm going to make[br]a new cell next century.

0:10:13.771,0:10:14.932
Ugh.

0:10:14.956,0:10:15.995
(Laughter)

0:10:16.019,0:10:21.128
So why is it that the rest[br]of biology moves so fast?

0:10:21.152,0:10:23.058
Why does a cell die after a day

0:10:23.082,0:10:25.593
and a human dies[br]after only a hundred years?

0:10:25.617,0:10:28.058
These seem like really[br]arbitrarily short limits

0:10:28.082,0:10:31.081
when you think about the total amount[br]of time in the universe.

0:10:31.105,0:10:33.916
But these are not arbitrary limits.

0:10:33.940,0:10:36.831
They're dictated by one simple thing,

0:10:36.855,0:10:38.914
and that thing is the Sun.

0:10:39.785,0:10:42.535
Once life figured out how to harness[br]the energy of the Sun

0:10:42.559,0:10:43.721
through photosynthesis,

0:10:43.745,0:10:46.664
we all had to speed up[br]and get on day and night cycles.

0:10:46.688,0:10:50.042
In that way, the Sun gave us[br]both a reason to be fast

0:10:50.066,0:10:51.673
and the fuel to do it.

0:10:51.697,0:10:54.556
You can view most of life on Earth[br]like a circulatory system,

0:10:54.580,0:10:56.270
and the Sun is our beating heart.

0:10:57.064,0:10:59.897
But the deep subsurface[br]is like a circulatory system

0:10:59.921,0:11:02.356
that's completely[br]disconnected from the Sun.

0:11:02.380,0:11:06.872
It's instead being driven[br]by long, slow geological rhythms.

0:11:07.933,0:11:13.321
There's currently no theoretical limit[br]on the lifespan of one single cell.

0:11:14.632,0:11:18.600
As long as there is at least[br]a tiny energy gradient to exploit,

0:11:18.624,0:11:20.808
theoretically, a single cell could live

0:11:20.832,0:11:22.974
for hundreds of thousands[br]of years or more,

0:11:22.998,0:11:25.442
simply by replacing[br]broken parts over time.

0:11:26.047,0:11:30.380
To ask a microbe that lives like that[br]to grow in our petri dishes

0:11:30.404,0:11:35.467
is to ask them to adapt to our frenetic,[br]Sun-centric, fast way of living,

0:11:35.491,0:11:37.984
and maybe they've got[br]better things to do than that.

0:11:38.008,0:11:39.317
(Laughter)

0:11:39.341,0:11:43.618
Imagine if we could figure out[br]how they managed to do this.

0:11:43.642,0:11:46.928
What if it involves some cool,[br]ultra-stable compounds

0:11:46.952,0:11:49.213
that we could use[br]to increase the shelf life

0:11:49.237,0:11:51.824
in biomedical or industrial applications?

0:11:51.848,0:11:54.404
Or maybe if we figure out[br]the mechanism that they use

0:11:54.428,0:11:57.546
to grow so extraordinarily slowly,

0:11:57.570,0:12:00.920
we could mimic it in cancer cells[br]and slow runaway cell division.

0:12:01.928,0:12:03.118
I don't know.

0:12:03.142,0:12:06.173
I mean, honestly, that is all speculation,

0:12:06.197,0:12:08.646
but the only thing I know for certain

0:12:08.670,0:12:12.743
is that there are[br]a hundred billion billion billlion

0:12:12.767,0:12:14.871
living microbial cells

0:12:14.895,0:12:17.093
underlying all the world's oceans.

0:12:17.117,0:12:21.482
That's 200 times more than the total[br]biomass of humans on this planet.

0:12:21.966,0:12:25.672
And those microbes have[br]a fundamentally different relationship

0:12:25.696,0:12:27.561
with time and energy than we do.

0:12:27.989,0:12:30.231
What seems like a day to them

0:12:30.255,0:12:32.572
might be a thousand years to us.

0:12:33.072,0:12:35.091
They don't care about the Sun,

0:12:35.115,0:12:37.326
and they don't care about growing fast,

0:12:37.350,0:12:40.247
and they probably don't give a damn[br]about my petri dishes ...

0:12:40.271,0:12:41.294
(Laughter)

0:12:41.334,0:12:45.260
but if we can continue to find[br]creative ways to study them,

0:12:45.284,0:12:51.619
then maybe we'll finally figure out[br]what life, all of life, is like on Earth.

0:12:52.031,0:12:53.182
Thank you.

0:12:53.206,0:12:54.998
(Applause)