0:00:01.365,0:00:04.837
I'm an ocean microbiologist[br]at the University of Tennessee,

0:00:04.837,0:00:07.294
and I want to tell you guys[br]about some microbes

0:00:07.294,0:00:10.624
that are so strange and wonderful

0:00:10.624,0:00:14.451
that they're challenging our assumptions[br]about what life is like on Earth.

0:00:14.451,0:00:15.904
So I have a question.

0:00:15.904,0:00:18.971
Please raise your hand if you've ever[br]thought it would be cool

0:00:18.971,0:00:22.203
to go to the bottom[br]of the ocean in a submarine?

0:00:22.623,0:00:23.746
Yes.

0:00:23.746,0:00:26.233
Most of you, because[br]the oceans are so cool.

0:00:26.233,0:00:28.673
Alright, now, please raise your hand

0:00:28.673,0:00:30.697
if the reason you raised your hand

0:00:30.697,0:00:32.273
to go to the bottom[br]of the ocean in the submarine

0:00:32.273,0:00:34.414
is because it would get you[br]a little bit closer

0:00:34.414,0:00:38.001
to that exciting mud that's down there.

0:00:38.001,0:00:39.576
Nobody.

0:00:39.576,0:00:41.515
I'm the only one in this room.

0:00:41.515,0:00:43.624
Well, I think about this all the time.

0:00:43.624,0:00:45.913
I spend most of my waking hours

0:00:45.913,0:00:47.194
trying to determine

0:00:47.194,0:00:49.775
how deep we can go into the Earth

0:00:49.775,0:00:53.525
and still find something,[br]anything, that's alive,

0:00:53.525,0:00:55.977
because we still don't know[br]the answer to this very basic question

0:00:55.977,0:00:57.499
about life on Earth.

0:00:57.499,0:01:01.084
So in the 1980s, a scientist[br]named John Parks in the UK

0:01:01.084,0:01:02.822
was similarly obsessed,

0:01:02.822,0:01:06.016
and he came up with a crazy idea.

0:01:06.016,0:01:11.197
He believed that there was a vast,[br]deep, and living microbial biosphere

0:01:11.197,0:01:13.135
underneath all the world's oceans

0:01:13.135,0:01:15.627
that extends hundreds[br]of meters into the seafloor,

0:01:15.627,0:01:16.909
which is cool,

0:01:16.909,0:01:20.005
but the only problem[br]is that nobody believed him,

0:01:20.005,0:01:22.932
and the reason that nobody believed him

0:01:22.932,0:01:28.135
is that ocean sediments may be[br]the most boring place on Earth.

0:01:28.135,0:01:31.460
There's no sunlight, there's no oxygen,

0:01:31.460,0:01:33.023
and perhaps worst of all,

0:01:33.023,0:01:34.751
there's no fresh food deliveries

0:01:34.751,0:01:37.306
for literally millions of years.

0:01:37.306,0:01:39.224
You don't have to have a PhD in biology

0:01:39.224,0:01:42.595
to know that that is a bad place[br]to go looking for life.

0:01:42.595,0:01:47.406
But in 2002, John had convinced[br]enough people that he was on to something

0:01:47.406,0:01:51.441
that he actually got an expedition[br]on this drill ship

0:01:51.441,0:01:53.297
called the Joides Resolution,

0:01:53.297,0:01:56.616
and he ran it along with[br]Bo Barker Jørgensen of Denmark.

0:01:56.616,0:02:00.038
And so they were finally able to get[br]some really good pristine

0:02:00.038,0:02:01.684
deep sub-surface samples

0:02:01.684,0:02:04.373
without contamination[br]from surface microbes.

0:02:04.373,0:02:06.277
This drill ship is capable of drilling

0:02:06.277,0:02:09.432
thousands of meters underneath the ocean,

0:02:09.432,0:02:12.091
and the mud comes up in sequential cores,

0:02:12.091,0:02:15.792
one after the other, long,[br]long cores that look like this.

0:02:15.792,0:02:19.656
This is being carried by scientists[br]such as myself who go on these ships,

0:02:19.656,0:02:21.994
and we process the cores on the ships[br]and then we send them home

0:02:21.994,0:02:24.742
to our home laboratories[br]for further study.

0:02:24.742,0:02:29.722
So when John and his colleagues[br]got these first precious

0:02:29.722,0:02:31.674
deep sea pristine samples,

0:02:31.674,0:02:32.446
they put them under the microscope,

0:02:32.446,0:02:35.982
and they saw images that looked[br]pretty much like this,

0:02:35.982,0:02:38.189
which is actually taken[br]from a more recent expedition

0:02:38.189,0:02:40.693
by my PhD student Joy Buongiorno.

0:02:40.693,0:02:43.005
You can see the hazy stuff[br]in the background.

0:02:43.005,0:02:45.814
That's mud. That's deep sea ocean mud,

0:02:45.814,0:02:49.643
and the bright green dots[br]stained with the green fluorescent dye

0:02:49.643,0:02:53.373
are real, living microbes.

0:02:53.373,0:02:56.223
Now I've got to tell you all something[br]really tragic about microbes.

0:02:56.223,0:02:58.134
They all look the same under a microbe,

0:02:58.134,0:03:00.104
I mean, to a first approximation.

0:03:00.104,0:03:03.282
You can take the most fascinating[br]organisms in the world,

0:03:03.282,0:03:07.415
like a microbe that literally[br]breathes uranium,

0:03:07.415,0:03:09.760
and another one that makes rocket fuel,

0:03:09.760,0:03:11.483
mix them up with some ocean mud,

0:03:11.483,0:03:13.499
put them underneath a microscope,

0:03:13.499,0:03:15.597
and they're just little dots.

0:03:15.597,0:03:17.051
It's really annoying.

0:03:17.051,0:03:19.426
So we can't use their looks[br]to tell them apart.

0:03:19.426,0:03:21.780
We have to use DNA like a fingerprint

0:03:21.780,0:03:23.438
to say who is who.

0:03:23.438,0:03:26.382
And I'll teach you guys[br]how to do it right now.

0:03:26.382,0:03:29.536
So I made up some data, and I'm going[br]to show you some data that are not real.

0:03:29.536,0:03:31.900
This is to illustrate[br]what it would look like

0:03:31.900,0:03:35.749
if a bunch of species were not[br]related to each other at all.

0:03:35.749,0:03:38.964
So you can see each species

0:03:38.964,0:03:43.387
has a list of combinations[br]of A, G, C, and T,

0:03:43.387,0:03:45.057
which are the four sub-units of DNA,

0:03:45.057,0:03:48.802
sort of randomly jumbled[br]and nothing looks like anything else

0:03:48.802,0:03:51.345
and these species are totally[br]unrelated to each other.

0:03:51.345,0:03:54.814
But this is what real DNA looks like[br]from a gene that these species

0:03:54.814,0:03:56.677
happen to share.

0:03:56.677,0:03:59.614
Everything lines up nearly perfectly.

0:03:59.614,0:04:03.079
The chances of getting[br]so many of those vertical columns

0:04:03.079,0:04:06.019
where every species has a C[br]or every species has a T

0:04:06.019,0:04:09.321
by random chance is infinitesimal.

0:04:09.321,0:04:14.178
So we know that all those species[br]had to have had a common ancestor.

0:04:14.178,0:04:16.213
They're all relatives of each other.

0:04:16.213,0:04:18.363
So now I'll tell you who they are.

0:04:18.363,0:04:21.166
The top two are us and chimpanzees,

0:04:21.166,0:04:25.524
which y'all already knew were related,[br]because, I mean, obviously,

0:04:25.524,0:04:29.071
but we're also related to things[br]that we don't look like,

0:04:29.071,0:04:33.469
like pine trees and giardia,[br]which is that gastrointestinal disease

0:04:33.469,0:04:36.409
you can get if you don't filter[br]your water while you're hiking.

0:04:36.409,0:04:39.762
We're also related to bacteria like e.coli

0:04:39.762,0:04:43.304
and Clostridium difficile, which is[br]a horrible, opportunistic pathogen

0:04:43.304,0:04:45.073
that kills lots of people.

0:04:45.073,0:04:49.271
But there's of course good microbes here,[br]like Dehalococcoides ethenogenes,

0:04:49.271,0:04:51.954
which cleans up[br]our industrial waste for us.

0:04:51.954,0:04:54.926
So if I take these DNA sequences,

0:04:54.926,0:04:57.690
and then I use them, the similarities[br]and differences between them,

0:04:57.690,0:04:59.946
to make a family tree for all of us

0:04:59.946,0:05:01.759
so you can see who is closely related,

0:05:01.759,0:05:03.540
then this is what it looks like.

0:05:03.540,0:05:06.071
So you can see clearly at a glance

0:05:06.071,0:05:11.317
that things like us and giardia[br]and bunnies and pine trees

0:05:11.317,0:05:13.212
are all, like, siblings,

0:05:13.212,0:05:16.383
and then the bacteria are,[br]like, our ancient cousins.

0:05:16.383,0:05:20.277
But we're kin to every[br]living thing on Earth.

0:05:20.277,0:05:22.918
So in my job, on a daily basis,

0:05:22.918,0:05:27.583
I get to produce scientific evidence[br]against existential loneliness.

0:05:27.583,0:05:30.248
So when we got these first DNA sequences

0:05:30.248,0:05:34.532
from the first crews of pristine samples[br]from the deep subsurface,

0:05:34.532,0:05:36.169
we wanted to know where they were.

0:05:36.169,0:05:38.957
So the first thing that we discovered[br]is that they were not aliens,

0:05:38.957,0:05:42.874
because we could get their DNA to line up[br]with everything else on Earth.

0:05:42.874,0:05:47.113
But now check out where they go[br]on our tree of life.

0:05:47.113,0:05:50.794
The first thing you'll notice[br]is that there's a lot of them.

0:05:50.794,0:05:54.256
It wasn't just one little species that[br]managed to live in this horrible place.

0:05:54.256,0:05:55.927
It's kind of a lot of things.

0:05:55.927,0:05:57.621
And the second thing that you'll notice,

0:05:57.621,0:06:03.682
hopefully, is that they're not[br]like anything we've ever seen before.

0:06:03.682,0:06:05.745
They are as different from each other

0:06:05.745,0:06:08.494
as they are from anything[br]that we've known before

0:06:08.494,0:06:10.714
as we are from pine trees.

0:06:10.714,0:06:13.919
So John Parks was completely correct.

0:06:13.919,0:06:19.071
He, and we, had discovered[br]a completely new and highly diverse

0:06:19.071,0:06:20.969
microbial ecosystem on Earth

0:06:20.969,0:06:25.407
that no one even knew existed[br]before the 1980s.

0:06:25.407,0:06:27.010
So now we were on a roll.

0:06:27.010,0:06:30.637
The next step was to grow[br]these exotic species

0:06:30.637,0:06:33.846
in a petri dish so that we could[br]do real experiments on them

0:06:33.846,0:06:35.941
like microbiologists are supposed to do.

0:06:35.941,0:06:37.674
But no matter what we fed them,

0:06:37.674,0:06:39.322
they refused to grow.

0:06:39.322,0:06:43.891
Even now, 15 years[br]and many expeditions later,

0:06:43.891,0:06:49.422
no human has ever gotten a single one[br]of these exotic deep subsurface microbes

0:06:49.422,0:06:51.212
to grow in a petri dish.

0:06:51.212,0:06:53.385
And it's not for lack of trying.

0:06:53.385,0:06:55.139
That may sound disappointing,

0:06:55.139,0:06:57.132
but I actually find it exhilarating,

0:06:57.132,0:07:00.787
because it means there are so many[br]tantalizing unknowns to work on.

0:07:00.787,0:07:02.842
Like, for instance, my colleagues[br]and I got what we thought

0:07:02.842,0:07:04.239
was a really great idea.

0:07:04.239,0:07:07.216
We were going to read their genes[br]like a recipe book,

0:07:07.216,0:07:10.914
find out what it was they wanted to eat,[br]and put it in their petri dishes,

0:07:10.914,0:07:12.987
and then they would grow and be happy.

0:07:12.987,0:07:14.404
but then when we looked at their genes,

0:07:14.404,0:07:18.220
it turns out that what they wanted to eat[br]was the food we were already feeding them.

0:07:18.220,0:07:20.480
So that was a total wash.

0:07:20.480,0:07:23.481
There was something else[br]that they wanted in their petri dishes

0:07:23.481,0:07:26.032
that we were just not giving them.

0:07:26.032,0:07:30.178
So by combining measurements[br]from many different places

0:07:30.178,0:07:31.205
around the world,

0:07:31.205,0:07:34.807
my colleagues at the University[br]of Southern California,

0:07:34.807,0:07:36.706
Doug LaRowe and Jan Amend,

0:07:36.706,0:07:41.504
were able to calculate that each one[br]of these deep sea microbial cells

0:07:41.504,0:07:44.941
requires only one zeptowatt of power,

0:07:44.941,0:07:48.858
and before you get your phones out,[br]a zepto is 10 to the minus 21,

0:07:48.858,0:07:50.624
because I know I would want[br]to look that up.

0:07:50.624,0:07:52.271
Humans, on the other hand,

0:07:52.271,0:07:55.098
require about a hundred watts of power.

0:07:55.098,0:07:58.633
So a hundred watts is basically[br]if you take a pineapple

0:07:58.633,0:08:04.749
and drop it from about waist height[br]to the ground 881,632 times a day.

0:08:04.749,0:08:07.144
If you did that and then[br]linked it up to a turbine,

0:08:07.144,0:08:11.187
that would create enough power[br]to make me happen for a day.

0:08:11.187,0:08:14.021
A zeptowatt, if you put it[br]in similar terms,

0:08:14.021,0:08:18.253
is if you take just one grain of salt

0:08:18.253,0:08:21.714
and then you imagine[br]a tiny, tiny, little ball

0:08:21.714,0:08:25.473
that is one thousandth of the mass[br]of that one grain of salt

0:08:25.473,0:08:28.139
and then you drop it one nanometer,

0:08:28.139,0:08:32.177
which is a hundred times smaller[br]than the wavelength of visible light,

0:08:32.177,0:08:34.870
once per day.

0:08:34.870,0:08:38.528
That's all it takes to make[br]these microbes live.

0:08:38.528,0:08:44.306
That's less energy than we ever thought[br]would be capable of supporting life,

0:08:44.306,0:08:47.124
but somehow, amazingly, beautifully,

0:08:47.124,0:08:49.230
it's enough.

0:08:49.230,0:08:52.608
So if these deep subsurface microbes[br]have a very different relationship

0:08:52.608,0:08:54.312
with energy than we previously thought,

0:08:54.312,0:08:56.172
then it follows that they'll have to have

0:08:56.172,0:08:59.096
a different relationship[br]with time as well,

0:08:59.096,0:09:02.095
because when you live[br]on such tiny energy gradients,

0:09:02.095,0:09:04.010
rapid growth is impossible.

0:09:04.010,0:09:06.721
If these things ever wanted[br]to colonize our throats and make us sick,

0:09:06.721,0:09:09.183
they would get muscled out[br]by fast-growing streptococcus

0:09:09.183,0:09:11.774
before they could even[br]initiate cell division.

0:09:11.774,0:09:15.469
So that's why we never[br]find them in our throats.

0:09:15.469,0:09:19.887
Perhaps the fact that the deep[br]subsurface is so boring

0:09:19.887,0:09:22.450
is actually an asset to these microbes.

0:09:22.450,0:09:24.641
They never get washed out by a storm.

0:09:24.641,0:09:27.325
They never get overgrown by weeds.

0:09:27.325,0:09:31.063
All they have to do is exist.

0:09:31.063,0:09:33.782
Maybe that thing that we were missing

0:09:33.782,0:09:36.877
in our petri dishes was not food at all.

0:09:36.877,0:09:38.288
Maybe it wasn't a chemical.

0:09:38.288,0:09:40.203
Maybe the thing that they really want,

0:09:40.203,0:09:44.023
the nutrient that they want, is time.

0:09:44.023,0:09:47.895
But time is the one thing[br]that I'll never be able to give them.

0:09:47.895,0:09:50.978
So even if I have a cell culture[br]that I pass to my PhD students,

0:09:50.978,0:09:53.550
who pass it to their[br]PhD students, and so on,

0:09:53.550,0:09:56.065
we'd have to do that[br]for thousands of years

0:09:56.065,0:09:59.495
in order to mimic the exact conditions[br]of the deep subsurface,

0:09:59.495,0:10:01.838
all without growing any contaminants.

0:10:01.838,0:10:03.885
It's just not possible.

0:10:03.885,0:10:07.020
But maybe in a way we already have[br]grown them in our petri dishes.

0:10:07.020,0:10:09.521
Maybe they looked at all that food[br]that we offered them and said,

0:10:09.521,0:10:11.272
thanks, I'm going to speed up so much

0:10:11.272,0:10:13.628
that I'm going to make[br]a new cell next century.

0:10:13.628,0:10:14.858
Ugh.

0:10:14.858,0:10:16.000
(Laughter)

0:10:16.000,0:10:21.361
So why is it that the rest[br]of biology moves so fast?

0:10:21.361,0:10:23.100
Why does a cell die after a day

0:10:23.100,0:10:25.817
and a human dies after[br]only a hundred years?

0:10:25.817,0:10:28.226
These seem like really[br]arbitrarily short limits

0:10:28.226,0:10:31.041
when you think about the total[br]amount of time in the universe.

0:10:31.041,0:10:34.140
But these are not arbitrary limits.

0:10:34.140,0:10:37.055
They're dictated by one simple thing,

0:10:37.055,0:10:39.985
and that thing is the Sun.

0:10:39.985,0:10:41.852
Once life figured out how to harness

0:10:41.852,0:10:43.927
the energy of the Sun[br]through photosynthesis,

0:10:43.927,0:10:46.920
we all had to speed up and get[br]on day and night cycles.

0:10:46.920,0:10:50.266
In that way, the Sun gave us[br]both a reason to be fast

0:10:50.266,0:10:51.989
and the fuel to do it.

0:10:51.989,0:10:54.689
You can view most of life on Earth[br]like a circulatory system,

0:10:54.689,0:10:56.803
and the Sun is our beating heart.

0:10:56.803,0:11:00.008
But the deep subsurface[br]is like a circulatory system

0:11:00.008,0:11:02.620
that's completely[br]disconnected from the Sun.

0:11:02.620,0:11:08.141
It's instead being driven[br]by long, slow geological rhythms.

0:11:08.141,0:11:10.996
There's currently no theoretical limit

0:11:10.996,0:11:14.865
on the lifespan of one single cell.

0:11:14.865,0:11:18.410
As long as there is at least[br]a tiny energy gradient to exploit,

0:11:18.410,0:11:22.582
theoretically, a single cell could live[br]for hundreds of thousands of years

0:11:22.582,0:11:26.287
or more, simply by replacing[br]broken parts over time.

0:11:26.287,0:11:30.483
To ask a microbe that lives like that[br]to grow in our petri dishes

0:11:30.483,0:11:35.343
is to ask them to adapt to our frenetic,[br]Sun-centric, fast way of living,

0:11:35.343,0:11:38.341
and maybe they've got[br]better things to do than that.

0:11:38.341,0:11:39.575
(Laughter)

0:11:39.575,0:11:43.875
Imagine if we could figure out[br]how they managed to do this.

0:11:43.875,0:11:46.898
What if it involves some cool,[br]ultra-stable compounds

0:11:46.898,0:11:49.247
that we could use[br]to increase the shelf life

0:11:49.247,0:11:52.003
in biomedical or industrial applications?

0:11:52.003,0:11:54.257
Or maybe if we figure out[br]the mechanism that they use

0:11:54.257,0:11:57.394
to grow so extraordinarily slowly,

0:11:57.394,0:12:01.348
we could mimic it in cancer cells[br]and slow runaway cell division.

0:12:01.348,0:12:03.198
I don't know.

0:12:03.198,0:12:05.926
I mean, honestly, that is all speculation,

0:12:05.926,0:12:08.870
but the only thing I know for certain

0:12:08.870,0:12:12.967
is that there are a hundred[br]billion billion billlion

0:12:12.967,0:12:17.286
living microbial cells underlying[br]all the world's oceans.

0:12:17.286,0:12:21.968
That's 200 times more than the total[br]biomass of humans on this planet.

0:12:21.968,0:12:25.470
And those microbes have[br]a fundamentally different relationship

0:12:25.470,0:12:28.056
with time and energy than we do.

0:12:28.056,0:12:30.279
What seems like a day to them

0:12:30.279,0:12:33.226
might be a thousand years to us.

0:12:33.226,0:12:35.315
They don't care about the Sun,

0:12:35.315,0:12:37.427
and they don't care about growing fast,

0:12:37.427,0:12:41.118
and they probably don't give[br]a damn about my petri dishes,

0:12:41.118,0:12:45.416
but if we can continue to find[br]creative ways to study them,

0:12:45.416,0:12:52.231
then maybe we'll finally figure out[br]what life, all of life, is like on Earth.

0:12:52.231,0:12:53.638
Thank you.

0:12:53.638,0:12:55.105
(Applause)