The mysterious microbes living deep inside the earth -- and how they could help humanity | K. Lloyd

124,487 views

2019-07-12 ・ TED


New videos

The mysterious microbes living deep inside the earth -- and how they could help humanity | K. Lloyd

124,487 views ・ 2019-07-12

TED


Please double-click on the English subtitles below to play the video.

00:12
It may seem like we're all standing on solid earth right now,
0
12667
3286
00:15
but we're not.
1
15977
1373
00:17
The rocks and the dirt underneath us are crisscrossed by tiny little fractures
2
17753
4397
00:22
and empty spaces.
3
22174
1399
00:23
And these empty spaces are filled with astronomical quantities of microbes,
4
23597
4929
00:28
such as these ones.
5
28550
1267
00:30
The deepest that we found microbes so far into the earth
6
30866
3363
00:34
is five kilometers down.
7
34253
1888
00:36
So like, if you pointed yourself at the ground
8
36165
2156
00:38
and took off running into the ground,
9
38345
2319
00:40
you could run an entire 5K race and microbes would line your whole path.
10
40688
3671
00:45
So you may not have ever thought about these microbes
11
45044
2524
00:47
that are deep inside earth's crust,
12
47592
1690
00:49
but you probably thought about the microbes living in our guts.
13
49306
2962
00:52
If you add up the gut microbiomes
14
52292
1817
00:54
of all the people and all the animals on the planet,
15
54133
2841
00:56
collectively, this weighs about 100,000 tons.
16
56998
3909
01:00
This is a huge biome that we carry in our bellies every single day.
17
60931
4293
01:05
We should all be proud.
18
65907
1417
01:07
(Laughter)
19
67348
1106
01:08
But it pales in comparison to the number of microbes
20
68478
3872
01:12
that are covering the entire surface of the earth,
21
72374
2485
01:14
like in our soils, our rivers and our oceans.
22
74883
2831
01:17
Collectively, these weigh about two billion tons.
23
77738
3873
01:22
But it turns out that the majority of microbes on earth
24
82174
2596
01:24
aren't even in oceans or our guts or sewage treatment plants.
25
84794
3777
01:28
Most of them are actually inside the earth's crust.
26
88595
2777
01:31
So collectively, these weigh 40 billion tons.
27
91396
3849
01:35
This is one of the biggest biomes on the planet,
28
95754
3291
01:39
and we didn't even know it existed until a few decades ago.
29
99069
3436
01:42
So the possibilities for what life is like down there,
30
102847
2695
01:45
or what it might do for humans,
31
105566
2545
01:48
are limitless.
32
108135
1700
01:50
This is a map showing a red dot
33
110367
1872
01:52
for every place where we've gotten pretty good deep subsurface samples
34
112263
3358
01:55
with modern microbiological methods,
35
115645
1818
01:57
and you may be impressed
36
117487
1383
01:58
that we're getting a pretty good global coverage,
37
118894
2310
02:01
but actually, if you remember that these are the only places
38
121228
2857
02:04
that we have samples from, it looks a little worse.
39
124109
2381
02:06
If we were all in an alien spaceship,
40
126514
1809
02:08
trying to reconstruct a map of the globe from only these samples,
41
128347
3659
02:12
we'd never be able to do it.
42
132030
2322
02:15
So people sometimes say to me,
43
135218
2301
02:17
"Yeah, there's a lot of microbes in the subsurface, but ...
44
137543
3516
02:21
aren't they just kind of dormant?"
45
141083
1650
02:23
This is a good point.
46
143710
1517
02:25
Relative to a ficus plant or the measles or my kid's guinea pigs,
47
145251
4850
02:30
these microbes probably aren't doing much of anything at all.
48
150125
3031
02:33
We know that they have to be slow, because there's so many of them.
49
153180
3826
02:37
If they all started dividing at the rate of E. coli,
50
157030
2690
02:39
then they would double the entire weight of the earth, rocks included,
51
159744
3317
02:43
over a single night.
52
163085
1476
02:45
In fact, many of them probably haven't even undergone a single cell division
53
165046
4533
02:49
since the time of ancient Egypt.
54
169603
2133
02:52
Which is just crazy.
55
172180
1460
02:53
Like, how do you wrap your head around things that are so long-lived?
56
173664
5578
02:59
But I thought of an analogy that I really love,
57
179266
3144
03:02
but it's weird and it's complicated.
58
182434
1821
03:04
So I hope that you can all go there with me.
59
184279
2171
03:06
Alright, let's try it.
60
186474
1246
03:08
It's like trying to figure out the life cycle of a tree ...
61
188299
2849
03:11
if you only lived for a day.
62
191172
1945
03:13
So like if human life span was only a day, and we lived in winter,
63
193141
4381
03:17
then you would go your entire life
64
197546
1625
03:19
without ever seeing a tree with a leaf on it.
65
199195
2573
03:21
And there would be so many human generations
66
201792
2055
03:23
that would pass by within a single winter
67
203871
2024
03:25
that you may not even have access to a history book
68
205919
2396
03:28
that says anything other than the fact that trees are always lifeless sticks
69
208339
3802
03:32
that don't do anything.
70
212165
1531
03:33
Of course, this is ridiculous.
71
213720
1659
03:35
We know that trees are just waiting for summer
72
215403
2150
03:37
so they can reactivate.
73
217577
1349
03:38
But if the human life span
74
218950
2175
03:41
were significantly shorter than that of trees,
75
221149
3079
03:44
we might be completely oblivious to this totally mundane fact.
76
224252
3855
03:48
So when we say that these deep subsurface microbes are just dormant,
77
228879
4928
03:53
are we like people who die after a day, trying to figure out how trees work?
78
233831
4172
03:58
What if these deep subsurface organisms
79
238601
1890
04:00
are just waiting for their version of summer,
80
240515
2307
04:02
but our lives are too short for us to see it?
81
242846
3067
04:06
If you take E. coli and seal it up in a test tube,
82
246784
3540
04:10
with no food or nutrients,
83
250348
1342
04:11
and leave it there for months to years,
84
251714
2468
04:14
most of the cells die off, of course, because they're starving.
85
254206
3016
04:17
But a few of the cells survive.
86
257246
2306
04:19
If you take these old surviving cells
87
259576
2190
04:21
and compete them, also under starvation conditions,
88
261790
2867
04:24
against a new, fast-growing culture of E. coli,
89
264681
3174
04:27
the grizzled old tough guys beat out the squeaky clean upstarts
90
267879
3739
04:31
every single time.
91
271642
1348
04:33
So this is evidence there's actually an evolutionary payoff
92
273339
4603
04:37
to being extraordinarily slow.
93
277966
2214
04:40
So it's possible
94
280736
1889
04:42
that maybe we should not equate being slow with being unimportant.
95
282649
6740
04:50
Maybe these out-of-sight, out-of-mind microbes
96
290402
2682
04:53
could actually be helpful to humanity.
97
293108
2207
04:56
OK, so as far as we know,
98
296125
1282
04:57
there are two ways to do subsurface living.
99
297431
2106
04:59
The first is to wait for food to trickle down from the surface world,
100
299871
3642
05:03
like trying to eat the leftovers of a picnic that happened 1,000 years ago.
101
303537
4508
05:08
Which is a crazy way to live,
102
308069
2024
05:10
but shockingly seems to work out for a lot of microbes in earth.
103
310117
3158
05:13
The other possibility is for a microbe to just say,
104
313698
3421
05:17
"Nah, I don't need the surface world.
105
317143
2475
05:19
I'm good down here."
106
319642
1453
05:21
For microbes that go this route,
107
321119
1672
05:22
they have to get everything that they need in order to survive
108
322815
3643
05:26
from inside the earth.
109
326482
1817
05:30
Some things are actually easier for them to get.
110
330205
2456
05:32
They're more abundant inside the earth,
111
332685
1868
05:34
like water or nutrients, like nitrogen and iron and phosphorus,
112
334577
3818
05:38
or places to live.
113
338419
1173
05:39
These are things that we literally kill each other to get ahold of
114
339616
3160
05:42
up at the surface world.
115
342800
1214
05:44
But in the subsurface, the problem is finding enough energy.
116
344038
3531
05:48
Up at the surface,
117
348101
1190
05:49
plants can chemically knit together carbon dioxide molecules into yummy sugars
118
349315
4088
05:53
as fast as the sun's photons hit their leaves.
119
353427
2976
05:56
But in the subsurface, of course, there's no sunlight,
120
356427
2528
05:58
so this ecosystem has to solve the problem
121
358979
2714
06:01
of who is going to make the food for everybody else.
122
361717
3265
06:05
The subsurface needs something that's like a plant
123
365416
3875
06:09
but it breathes rocks.
124
369315
1787
06:11
Luckily, such a thing exists,
125
371641
3135
06:14
and it's called a chemolithoautotroph.
126
374800
2324
06:17
(Laughter)
127
377148
1008
06:18
Which is a microbe that uses chemicals -- "chemo,"
128
378180
4024
06:22
from rocks -- "litho,"
129
382228
2230
06:24
to make food -- "autotroph."
130
384482
2762
06:27
And they can do this with a ton of different elements.
131
387268
2658
06:29
They can do this with sulphur, iron, manganese, nitrogen, carbon,
132
389950
3833
06:33
some of them can use pure electrons, straight up.
133
393807
3230
06:37
Like, if you cut the end off of an electrical cord,
134
397530
2412
06:39
they could breathe it like a snorkel.
135
399966
1909
06:41
(Laughter)
136
401899
1312
06:43
These chemolithoautotrophs
137
403235
1501
06:44
take the energy that they get from these processes
138
404760
2635
06:47
and use it to make food, like plants do.
139
407419
2412
06:49
But we know that plants do more than just make food.
140
409855
2803
06:53
They also make a waste product, oxygen,
141
413103
2316
06:55
which we are 100 percent dependent upon.
142
415443
2028
06:57
But the waste product that these chemolithoautotrophs make
143
417992
3285
07:01
is often in the form of minerals,
144
421301
1967
07:03
like rust or pyrite, like fool's gold,
145
423292
4579
07:07
or carminites, like limestone.
146
427895
2000
07:10
So what we have are microbes that are really, really slow, like rocks,
147
430680
6603
07:18
that get their energy from rocks,
148
438243
3406
07:21
that make as their waste product other rocks.
149
441673
3197
07:25
So am I talking about biology, or am I talking about geology?
150
445268
3821
07:29
This stuff really blurs the lines.
151
449466
2143
07:31
(Laughter)
152
451633
1004
07:32
So if I'm going to do this thing,
153
452661
2146
07:34
and I'm going to be a biologist who studies microbes
154
454831
3318
07:38
that kind of act like rocks,
155
458173
2205
07:40
then I should probably start studying geology.
156
460402
3374
07:43
And what's the coolest part of geology?
157
463800
3110
07:47
Volcanoes.
158
467292
1168
07:48
(Laughter)
159
468484
1251
07:49
This is looking inside the crater of Poás Volcano in Costa Rica.
160
469759
3721
07:53
Many volcanoes on earth arise because an oceanic tectonic plate
161
473854
3778
07:57
crashes into a continental plate.
162
477656
1810
07:59
As this oceanic plate subducts
163
479490
1913
08:01
or gets moved underneath this continental plate,
164
481427
2365
08:03
things like water and carbon dioxide and other materials
165
483816
2841
08:06
get squeezed out of it,
166
486681
1235
08:07
like ringing a wet washcloth.
167
487940
1726
08:10
So in this way, subduction zones are like portals into the deep earth,
168
490382
3682
08:14
where materials are exchanged between the surface and the subsurface world.
169
494088
3761
08:17
So I was recently invited by some of my colleagues in Costa Rica
170
497873
3028
08:20
to come and work with them on some of the volcanoes.
171
500925
3103
08:24
And of course I said yes, because, I mean, Costa Rica is beautiful,
172
504052
4598
08:28
but also because it sits on top of one of these subduction zones.
173
508674
3280
08:32
We wanted to ask the very specific question:
174
512478
2794
08:35
Why is it that the carbon dioxide
175
515296
2388
08:37
that comes out of this deeply buried oceanic tectonic plate
176
517708
2976
08:40
is only coming out of the volcanoes?
177
520708
2107
08:42
Why don't we see it distributed throughout the entire subduction zone?
178
522839
3294
08:46
Do the microbes have something to do with that?
179
526157
2483
08:48
So this is a picture of me inside Poás Volcano,
180
528664
3623
08:52
along with my colleague Donato Giovannelli.
181
532311
2184
08:54
That lake that we're standing next to is made of pure battery acid.
182
534519
3602
08:58
I know this because we were measuring the pH when this picture was taken.
183
538145
3722
09:02
And at some point while we were working inside the crater,
184
542362
2731
09:05
I turned to my Costa Rican colleague Carlos Ramírez and I said,
185
545117
4579
09:09
"Alright, if this thing starts erupting right now,
186
549720
3367
09:13
what's our exit strategy?"
187
553111
1733
09:15
And he said, "Oh, yeah, great question, it's totally easy.
188
555269
3143
09:18
Just turn around and enjoy the view."
189
558436
3078
09:21
(Laughter)
190
561538
1293
09:22
"Because it will be your last."
191
562855
1547
09:24
(Laughter)
192
564426
1135
09:25
And it may sound like he was being overly dramatic,
193
565585
3445
09:29
but 54 days after I was standing next to that lake,
194
569054
4753
09:33
this happened.
195
573831
1421
09:35
Audience: Oh!
196
575276
1158
09:37
Freaking terrifying, right?
197
577204
1650
09:38
(Laughs)
198
578878
1150
09:40
This was the biggest eruption this volcano had had in 60-some-odd years,
199
580934
4353
09:45
and not long after this video ends,
200
585311
2484
09:47
the camera that was taking the video is obliterated
201
587819
2643
09:50
and the entire lake that we had been sampling
202
590486
2420
09:52
vaporizes completely.
203
592930
1400
09:54
But I also want to be clear
204
594815
1802
09:56
that we were pretty sure this was not going to happen
205
596641
2500
09:59
on the day that we were actually in the volcano,
206
599165
2253
10:01
because Costa Rica monitors its volcanoes very carefully
207
601442
2633
10:04
through the OVSICORI Institute,
208
604099
1563
10:05
and we had scientists from that institute with us on that day.
209
605686
3206
10:08
But the fact that it erupted illustrates perfectly
210
608916
3090
10:12
that if you want to look for where carbon dioxide gas
211
612030
2508
10:14
is coming out of this oceanic plate,
212
614562
1864
10:16
then you should look no further than the volcanoes themselves.
213
616450
3103
10:19
But if you go to Costa Rica,
214
619577
2269
10:21
you may notice that in addition to these volcanoes
215
621870
2460
10:24
there are tons of cozy little hot springs all over the place.
216
624354
3244
10:28
Some of the water in these hot springs is actually bubbling up
217
628069
3270
10:31
from this deeply buried oceanic plate.
218
631363
2301
10:33
And our hypothesis was that there should be carbon dioxide
219
633688
3496
10:37
bubbling up with it,
220
637208
1179
10:38
but something deep underground was filtering it out.
221
638411
3182
10:41
So we spent two weeks driving all around Costa Rica,
222
641617
4182
10:45
sampling every hot spring we could find --
223
645823
2897
10:48
it was awful, let me tell you.
224
648744
1674
10:50
And then we spent the next two years measuring and analyzing data.
225
650442
5636
10:56
And if you're not a scientist, I'll just let you know that the big discoveries
226
656102
3809
10:59
don't really happen when you're at a beautiful hot spring
227
659935
2833
11:02
or on a public stage;
228
662792
1151
11:03
they happen when you're hunched over a messy computer
229
663967
2523
11:06
or you're troubleshooting a difficult instrument,
230
666514
2317
11:08
or you're Skyping your colleagues
231
668855
1738
11:10
because you are completely confused about your data.
232
670617
2595
11:13
Scientific discoveries, kind of like deep subsurface microbes,
233
673236
3331
11:16
can be very, very slow.
234
676591
1768
11:19
But in our case, this really paid off this one time.
235
679267
3349
11:22
We discovered that literally tons of carbon dioxide
236
682640
4278
11:26
were coming out of this deeply buried oceanic plate.
237
686942
3183
11:30
And the thing that was keeping them underground
238
690149
2349
11:32
and keeping it from being released out into the atmosphere
239
692522
2995
11:35
was that deep underground,
240
695541
1560
11:37
underneath all the adorable sloths and toucans of Costa Rica,
241
697125
3984
11:41
were chemolithoautotrophs.
242
701133
1800
11:43
These microbes and the chemical processes that were happening around them
243
703338
3501
11:46
were converting this carbon dioxide into carbonate mineral
244
706863
2752
11:49
and locking it up underground.
245
709639
1928
11:51
Which makes you wonder:
246
711591
2294
11:53
If these subsurface processes are so good at sucking up
247
713909
3501
11:57
all the carbon dioxide coming from below them,
248
717434
2581
12:00
could they also help us with a little carbon problem
249
720039
2460
12:02
we've got going on up at the surface?
250
722523
2165
12:05
Humans are releasing enough carbon dioxide into our atmosphere
251
725006
4325
12:09
that we are decreasing the ability of our planet
252
729355
2974
12:12
to support life as we know it.
253
732353
2000
12:14
And scientists and engineers and entrepreneurs
254
734704
2432
12:17
are working on methods to pull carbon dioxide
255
737160
2504
12:19
out of these point sources,
256
739688
1293
12:21
so that they're not released into the atmosphere.
257
741005
2318
12:23
And they need to put it somewhere.
258
743347
1651
12:25
So for this reason,
259
745022
1177
12:26
we need to keep studying places where this carbon might be stored,
260
746223
3338
12:29
possibly in the subsurface,
261
749585
2294
12:31
to know what's going to happen to it when it goes there.
262
751903
2643
12:34
Will these deep subsurface microbes be a problem because they're too slow
263
754570
3467
12:38
to actually keep anything down there?
264
758061
1881
12:39
Or will they be helpful
265
759966
1408
12:41
because they'll help convert this stuff to solid carbonate minerals?
266
761398
3790
12:45
If we can make such a big breakthrough
267
765712
2420
12:48
just from one study that we did in Costa Rica,
268
768156
2386
12:50
then imagine what else is waiting to be discovered down there.
269
770566
2967
12:53
This new field of geo-bio-chemistry, or deep subsurface biology,
270
773891
5665
12:59
or whatever you want to call it,
271
779580
1541
13:01
is going to have huge implications,
272
781145
1837
13:03
not just for mitigating climate change,
273
783006
2373
13:05
but possibly for understanding how life and earth have coevolved,
274
785403
3872
13:09
or finding new products that are useful for industrial or medical applications.
275
789613
4698
13:14
Maybe even predicting earthquakes
276
794335
2262
13:16
or finding life outside our planet.
277
796621
2198
13:18
It could even help us understand the origin of life itself.
278
798843
3126
13:22
Fortunately, I don't have to do this by myself.
279
802827
2825
13:25
I have amazing colleagues all over the world
280
805962
3325
13:29
who are cracking into the mysteries of this deep subsurface world.
281
809311
3292
13:33
And it may seem like life buried deep within the earth's crust
282
813831
4810
13:38
is so far away from our daily experiences that it's kind of irrelevant.
283
818665
3974
13:43
But the truth is that this weird, slow life
284
823363
3688
13:47
may actually have the answers to some of the greatest mysteries
285
827075
3525
13:50
of life on earth.
286
830624
1150
13:52
Thank you.
287
832225
1151
13:53
(Applause)
288
833400
5044
About this website

This site will introduce you to YouTube videos that are useful for learning English. You will see English lessons taught by top-notch teachers from around the world. Double-click on the English subtitles displayed on each video page to play the video from there. The subtitles scroll in sync with the video playback. If you have any comments or requests, please contact us using this contact form.

https://forms.gle/WvT1wiN1qDtmnspy7