WEBVTT 00:00:00.667 --> 00:00:03.953 It may seem like we're all standing on solid earth right now, 00:00:03.977 --> 00:00:05.350 but we're not. 00:00:05.753 --> 00:00:10.150 The rocks and the dirt underneath us are crisscrossed by tiny little fractures 00:00:10.174 --> 00:00:11.573 and empty spaces. 00:00:11.597 --> 00:00:16.526 And these empty spaces are filled with astronomical quantities of microbes 00:00:16.550 --> 00:00:17.817 such as these ones. 00:00:18.866 --> 00:00:22.229 The deepest that we found microbes so far into the earth 00:00:22.253 --> 00:00:24.141 is five kilometers down. 00:00:24.165 --> 00:00:26.321 So like, if you pointed yourself at the ground 00:00:26.345 --> 00:00:28.664 and took off running into the ground, 00:00:28.688 --> 00:00:32.359 you could run an entire 5K race and microbes would line your whole path. NOTE Paragraph 00:00:33.044 --> 00:00:35.568 So you may not have ever thought about these microbes 00:00:35.592 --> 00:00:37.282 that are deep inside earth's crust, 00:00:37.306 --> 00:00:40.268 but you probably thought about the microbes living in our guts. 00:00:40.292 --> 00:00:42.109 If you add up the gut microbiomes 00:00:42.133 --> 00:00:44.974 of all the people and all the animals on the planet, 00:00:44.998 --> 00:00:48.907 collectively, this weighs about 100,000 tons. 00:00:48.931 --> 00:00:53.224 This is a huge biome that we carry in our bellies every single day. 00:00:53.907 --> 00:00:55.324 We should all be proud. NOTE Paragraph 00:00:55.348 --> 00:00:56.454 (Laughter) NOTE Paragraph 00:00:56.478 --> 00:01:00.350 But it pales in comparison to the number of microbes 00:01:00.374 --> 00:01:02.859 that are covering the entire surface of the earth, 00:01:02.883 --> 00:01:05.714 like in our soils, our rivers and our oceans. 00:01:05.738 --> 00:01:09.611 Collectively, these weigh about two billion tons. 00:01:10.174 --> 00:01:12.770 But it turns out that the majority of microbes on earth 00:01:12.794 --> 00:01:16.571 aren't even in oceans or our guts or sewage treatment plants. 00:01:16.595 --> 00:01:19.372 Most of them are actually inside the earth's crust. 00:01:19.396 --> 00:01:23.245 So collectively, these weigh 40 billion tons. 00:01:23.754 --> 00:01:27.045 This is one of the biggest biomes on the planet, 00:01:27.069 --> 00:01:30.505 and we didn't even know it existed until a few decades ago. 00:01:30.847 --> 00:01:33.542 So the possibilities for what life is like down there 00:01:33.566 --> 00:01:36.111 or what it might do for humans 00:01:36.135 --> 00:01:37.835 are limitless. NOTE Paragraph 00:01:38.367 --> 00:01:40.239 This is a map showing a red dot 00:01:40.263 --> 00:01:43.621 for every place where we've gotten pretty good deep subsurface samples 00:01:43.645 --> 00:01:45.463 with modern microbiological methods 00:01:45.487 --> 00:01:46.870 and you may be impressed 00:01:46.894 --> 00:01:49.204 that we're getting a pretty good global coverage, 00:01:49.228 --> 00:01:52.085 but actually, if you remember that these are the only places 00:01:52.109 --> 00:01:54.490 that we have samples from, it looks a little worse. 00:01:54.514 --> 00:01:56.323 If we were all in an alien spaceship, 00:01:56.347 --> 00:02:00.006 trying to reconstruct the map of the globe from only these samples, 00:02:00.030 --> 00:02:02.352 we'd never be able to do it. NOTE Paragraph 00:02:03.218 --> 00:02:05.519 So people sometimes say to me, 00:02:05.543 --> 00:02:09.059 "Yeah, there's a lot of microbes in the subsurface, but ... 00:02:09.083 --> 00:02:10.733 aren't they just kind of dormant?" 00:02:11.710 --> 00:02:13.227 This is a good point. 00:02:13.251 --> 00:02:18.101 Relative to a ficus plant or the measles or my kid's guinea pigs, 00:02:18.125 --> 00:02:21.156 these microbes probably aren't doing much of anything at all. 00:02:21.180 --> 00:02:25.006 We know that they have to be slow, because there's so many of them. 00:02:25.030 --> 00:02:27.720 If they all started dividing at the rate of E. coli, 00:02:27.744 --> 00:02:31.061 then they would double the entire weight of the earth, rocks included, 00:02:31.085 --> 00:02:32.561 over a single night. 00:02:33.046 --> 00:02:37.579 In fact, many of them probably haven't even undergone a single cell division 00:02:37.603 --> 00:02:39.736 since the time of ancient Egypt. 00:02:40.180 --> 00:02:41.640 Which is just crazy. 00:02:41.664 --> 00:02:47.242 Like, how do you wrap your head around things that are so long-lived? NOTE Paragraph 00:02:47.266 --> 00:02:50.410 But I thought of an analogy that I really love, 00:02:50.434 --> 00:02:52.255 but it's weird and it's complicated. 00:02:52.279 --> 00:02:54.450 So I hope that you can all go there with me. 00:02:54.474 --> 00:02:55.720 Alright, let's try it. 00:02:56.299 --> 00:02:59.148 It's like trying to figure out the life cycle of a tree 00:02:59.172 --> 00:03:01.117 if you only lived for a day. 00:03:01.141 --> 00:03:05.522 So like if human life span was only a day, and we lived in winter, 00:03:05.546 --> 00:03:07.171 then you would go your entire life 00:03:07.195 --> 00:03:09.768 without ever seeing a tree with a leaf on it. 00:03:09.792 --> 00:03:11.847 And there would be so many human generations 00:03:11.871 --> 00:03:13.895 that would pass by within a single winter 00:03:13.919 --> 00:03:16.315 that you may not even have access to a history book 00:03:16.339 --> 00:03:20.141 that says anything other than the fact that trees are always lifeless sticks 00:03:20.165 --> 00:03:21.696 that don't do anything. 00:03:21.720 --> 00:03:23.379 Of course, this is ridiculous. 00:03:23.403 --> 00:03:25.553 We know that trees are just waiting for summer 00:03:25.577 --> 00:03:26.926 so they can reactivate. 00:03:26.950 --> 00:03:29.125 But if the human life span 00:03:29.149 --> 00:03:32.228 were significantly shorter than that of trees, 00:03:32.252 --> 00:03:36.107 we might be completely oblivious to this totally mundane fact. NOTE Paragraph 00:03:36.879 --> 00:03:41.807 So when we say that these deep subsurface microbes are just dormant, 00:03:41.831 --> 00:03:46.003 are we like people who die after a day, trying to figure out how trees work? 00:03:46.601 --> 00:03:48.491 What if these deep subsurface organisms 00:03:48.515 --> 00:03:50.822 are just waiting for their version of summer, 00:03:50.846 --> 00:03:53.913 but our lives are too short for us to see it? 00:03:54.784 --> 00:03:58.324 If you take E. coli and seal it up in a test tube, 00:03:58.348 --> 00:03:59.690 with no food or nutrients, 00:03:59.714 --> 00:04:02.182 and you leave it there for moths to years, 00:04:02.206 --> 00:04:05.222 most of the cells die off, of course, because they're starving. 00:04:05.246 --> 00:04:07.552 But a few of the cells survive. 00:04:07.576 --> 00:04:09.766 If you take these old surviving cells 00:04:09.790 --> 00:04:12.657 and compete them, also under starvation conditions, 00:04:12.681 --> 00:04:15.855 against a new, fast-growing culture of E. coli, 00:04:15.879 --> 00:04:19.618 the grizzled old tough guys beat out the squeaky clean upstarts 00:04:19.642 --> 00:04:20.990 every single time. 00:04:21.339 --> 00:04:25.942 So this is evidence there's actually an evolutionary payoff 00:04:25.966 --> 00:04:28.180 to being extraordinarily slow. 00:04:28.736 --> 00:04:30.625 So it's possible 00:04:30.649 --> 00:04:37.389 that maybe we should not equate being slow with being unimportant. 00:04:38.402 --> 00:04:41.084 Maybe these out-of-sight, out-of-mind microbes 00:04:41.108 --> 00:04:43.315 could actually be helpful to humanity. NOTE Paragraph 00:04:44.125 --> 00:04:45.407 OK, so as far as we know, 00:04:45.431 --> 00:04:47.537 there are two ways to do subsurface living. 00:04:47.871 --> 00:04:51.513 The first is to wait for food to trickle down from the surface world, 00:04:51.537 --> 00:04:56.045 like trying to eat the leftovers of a picnic that happened 1,000 years ago. 00:04:56.069 --> 00:04:58.093 Which is a crazy way to live, 00:04:58.117 --> 00:05:01.275 but shockingly seems to work out for a lot of microbes in earth. 00:05:01.698 --> 00:05:05.119 The other possibility is for a microbe to just say, 00:05:05.143 --> 00:05:07.618 "Nah, I don't need the surface world. 00:05:07.642 --> 00:05:09.095 I'm good down here." 00:05:09.119 --> 00:05:10.791 For microbes that go this route, 00:05:10.815 --> 00:05:14.458 they have to get everything that they need in order to survive 00:05:14.482 --> 00:05:16.299 from inside the earth. 00:05:18.205 --> 00:05:20.661 Some things are actually easier for them to get. 00:05:20.685 --> 00:05:22.553 They're more abundant inside the earth, 00:05:22.577 --> 00:05:26.395 like water or nutrients, like nitrogen and iron and phosphorus, 00:05:26.419 --> 00:05:27.592 or places to live. 00:05:27.616 --> 00:05:30.776 These are things that we literally kill each other to get ahold of 00:05:30.800 --> 00:05:32.014 up at the surface world. NOTE Paragraph 00:05:32.038 --> 00:05:35.569 But in the subsurface, the problem is finding enough energy. 00:05:36.101 --> 00:05:37.291 Up at the surface, 00:05:37.315 --> 00:05:41.403 plants can chemically knit together carbon dioxide molecules into yummy sugars 00:05:41.427 --> 00:05:44.403 as fast as the sun's photons hit their leaves. 00:05:44.427 --> 00:05:46.955 But in the subsurface, of course, there's no sunlight, 00:05:46.979 --> 00:05:49.693 so this ecosystem has to solve the problem 00:05:49.717 --> 00:05:52.982 of who is going to make the food for everybody else. 00:05:53.416 --> 00:05:57.291 The subsurface needs something that's like a plant 00:05:57.315 --> 00:05:59.102 but it breaths rocks. 00:05:59.641 --> 00:06:02.776 Luckily, such a thing exists, 00:06:02.800 --> 00:06:05.124 and it's called a chemolithoautotroph. NOTE Paragraph 00:06:05.148 --> 00:06:06.156 (Laughter) NOTE Paragraph 00:06:06.180 --> 00:06:10.204 Which is a microbe that uses chemicals -- "chemo," 00:06:10.228 --> 00:06:12.458 from rocks -- "litho," 00:06:12.482 --> 00:06:15.244 to make food -- "autotroph." 00:06:15.268 --> 00:06:17.926 And they can do this with a ton of different elements. 00:06:17.950 --> 00:06:21.783 They can do this with sulphur, iron, manganese, nitrogen, carbon, 00:06:21.807 --> 00:06:25.037 some of them can use pure electrons, straight up. 00:06:25.530 --> 00:06:27.942 Like, if you cut the end off of an electrical cord, 00:06:27.966 --> 00:06:29.875 they could breath it like a snorkel. NOTE Paragraph 00:06:29.899 --> 00:06:31.211 (Laughter) NOTE Paragraph 00:06:31.235 --> 00:06:32.736 These chemolithoautotrophes 00:06:32.760 --> 00:06:35.395 take the energy that they get from these processes 00:06:35.419 --> 00:06:37.831 and use it to make food, like plants do. 00:06:37.855 --> 00:06:40.658 But we know that plants do more than just make food. 00:06:41.103 --> 00:06:43.419 They also make a waste product, oxygen, 00:06:43.443 --> 00:06:45.471 which we are 100 percent dependent upon. 00:06:45.992 --> 00:06:49.277 But the waste product that these chemolithoautotrophes make 00:06:49.301 --> 00:06:51.268 is often in the form of minerals, 00:06:51.292 --> 00:06:55.871 like rust or pyrite, like fool's gold, 00:06:55.895 --> 00:06:57.895 or carminites, like limestone. 00:06:58.680 --> 00:07:05.283 So what we have are microbes that are really, really slow, like rocks, 00:07:06.243 --> 00:07:09.649 that get their energy from rocks, 00:07:09.673 --> 00:07:12.870 that make as their waste product other rocks. 00:07:13.268 --> 00:07:17.089 So am I talking about biology or am I talking about geology? 00:07:17.466 --> 00:07:19.609 This stuff really blurs the lines. NOTE Paragraph 00:07:19.633 --> 00:07:20.637 (Laughter) NOTE Paragraph 00:07:20.661 --> 00:07:22.807 So if I'm going to do this thing, 00:07:22.831 --> 00:07:26.149 and I'm going to be a biologist who studies microbes 00:07:26.173 --> 00:07:28.378 that kind of act like rocks, 00:07:28.402 --> 00:07:31.776 then I should probably start studying geology. 00:07:31.800 --> 00:07:34.910 And what's the coolest part of geology? 00:07:35.292 --> 00:07:36.460 Volcanoes. NOTE Paragraph 00:07:36.484 --> 00:07:37.735 (Laughter) NOTE Paragraph 00:07:37.759 --> 00:07:41.480 This is looking inside the crater of Poás Volcano in Costa Rica. 00:07:41.854 --> 00:07:45.632 Many volcanoes on earth arise because an oceanic tectonic plate 00:07:45.656 --> 00:07:47.466 crashes into a continental plate. 00:07:47.490 --> 00:07:49.403 As this oceanic plate subducts 00:07:49.427 --> 00:07:51.792 or gets moved underneath this continental plate, 00:07:51.816 --> 00:07:54.657 things like water and carbon dioxide and other materials 00:07:54.681 --> 00:07:55.916 get squeezed out of it, 00:07:55.940 --> 00:07:57.666 like ringing a wet washcloth. 00:07:58.382 --> 00:08:02.064 So in this way, subduction zones are like portals into the deep earth, 00:08:02.088 --> 00:08:05.849 where materials are exchanged between the surface and the subsurface world. NOTE Paragraph 00:08:05.873 --> 00:08:08.901 So I was recently invited by some of my colleagues in Costa Rica 00:08:08.925 --> 00:08:12.028 to come and work with them on some of the volcanoes. 00:08:12.052 --> 00:08:16.650 And of course I said yes, because, I mean, Costa Rica is beautiful, 00:08:16.674 --> 00:08:19.954 but also because it sits on top of one of these subduction zones. 00:08:20.478 --> 00:08:23.272 We wanted to ask the very specific question, 00:08:23.296 --> 00:08:25.684 why is it that the carbon dioxide 00:08:25.708 --> 00:08:28.684 that comes out of this deeply buried oceanic tectonic plate 00:08:28.708 --> 00:08:30.815 is only coming out of the volcanoes? 00:08:30.839 --> 00:08:34.133 Why don't we see it distributed throughout the entire subduction zone? 00:08:34.157 --> 00:08:36.640 Do the microbes have something to do with that? NOTE Paragraph 00:08:36.664 --> 00:08:40.287 So this is a picture of me inside Poás Volcano, 00:08:40.311 --> 00:08:42.495 along with my colleague Donato Giovannelli. 00:08:42.519 --> 00:08:46.121 That lake that we're standing next to is made of pure battery acid. 00:08:46.145 --> 00:08:49.867 I know this because we were measuring the pH when this picture was taken. 00:08:50.362 --> 00:08:53.093 And at some point while we were working inside the crater, 00:08:53.117 --> 00:08:57.696 I turned to my Costa Rican colleague Carlos Ramírez and I said, 00:08:57.720 --> 00:09:01.087 "Alright, if this thing starts erupting right now, 00:09:01.111 --> 00:09:02.844 what's our exit strategy?" 00:09:03.269 --> 00:09:06.412 And he said, "Oh, yeah, great question, it's totally easy. 00:09:06.436 --> 00:09:09.514 Just turn around and enjoy the view." NOTE Paragraph 00:09:09.538 --> 00:09:10.831 (Laughter) NOTE Paragraph 00:09:10.855 --> 00:09:12.402 "Because it will be your last." NOTE Paragraph 00:09:12.426 --> 00:09:13.561 (Laughter) NOTE Paragraph 00:09:13.585 --> 00:09:17.030 And it may sound like he was being overly dramatic, 00:09:17.054 --> 00:09:21.807 but 54 days after I was standing next to that lake, 00:09:21.831 --> 00:09:23.252 this happened. NOTE Paragraph 00:09:23.276 --> 00:09:24.434 Audience: Oh! NOTE Paragraph 00:09:25.204 --> 00:09:26.854 Freaking terrifying, right? NOTE Paragraph 00:09:26.878 --> 00:09:28.028 (Laughs) NOTE Paragraph 00:09:28.934 --> 00:09:33.287 This was the biggest eruption this volcano had had in 60-some-odd years, 00:09:33.311 --> 00:09:35.795 and not long after this video ends, 00:09:35.819 --> 00:09:38.462 the camera that was taking the video is obliterated 00:09:38.486 --> 00:09:40.906 and the entire lake that we had been sampling 00:09:40.930 --> 00:09:42.330 vaporizes completely. 00:09:42.815 --> 00:09:44.617 But I also want to be clear 00:09:44.641 --> 00:09:47.141 that we were pretty sure this was not going to happen 00:09:47.165 --> 00:09:49.418 on the day that we were actually in the volcano, 00:09:49.442 --> 00:09:52.075 because Costa Rica monitors its volcanoes very carefully 00:09:52.099 --> 00:09:53.662 through the OVSICORI Institute, 00:09:53.686 --> 00:09:56.892 and we had scientists from that institute with us on that day. 00:09:56.916 --> 00:10:00.006 But the fact that it erupted illustrates perfectly 00:10:00.030 --> 00:10:02.538 that if you want to look for where carbon dioxide gas 00:10:02.562 --> 00:10:04.426 is coming out of this oceanic plate, 00:10:04.450 --> 00:10:07.553 then you should look no further than the volcanoes themselves. NOTE Paragraph 00:10:07.577 --> 00:10:09.846 But if you go to Costa Rica, 00:10:09.870 --> 00:10:12.330 you may notice that in addition to these volcanoes 00:10:12.354 --> 00:10:15.598 there are tons of cosy little hot springs all over the place. 00:10:16.069 --> 00:10:19.339 Some of the water in these hot springs is actually bubbling up 00:10:19.363 --> 00:10:21.664 from this deeply buried oceanic plate. 00:10:21.688 --> 00:10:25.184 And our hypothesis was that there should be carbon dioxide 00:10:25.208 --> 00:10:26.387 bubbling up with it, 00:10:26.411 --> 00:10:29.593 but something deep underground was filtering it out. NOTE Paragraph 00:10:29.617 --> 00:10:33.799 So we spent two weeks driving all around Costa Rica, 00:10:33.823 --> 00:10:36.720 sampling every hot spring we could find -- 00:10:36.744 --> 00:10:38.418 it was awful, let me tell you -- 00:10:38.442 --> 00:10:44.078 and then, we spent the next two years measuring and analyzing data, 00:10:44.102 --> 00:10:47.911 and if you're not a scientist, I'll just let you know that the big discoveries 00:10:47.935 --> 00:10:50.768 don't really happen when you're in a beautiful hot spring 00:10:50.792 --> 00:10:51.943 or on a public stage, 00:10:51.967 --> 00:10:54.490 they happen when you're hunched over a messy computer 00:10:54.514 --> 00:10:56.831 or you're troubleshooting a difficult instrument, 00:10:56.855 --> 00:10:58.593 or you're Skyping your colleagues 00:10:58.617 --> 00:11:01.212 because you are completely confused about your data. 00:11:01.236 --> 00:11:04.567 Scientific discoveries, kind of like deep subsurface microbes, 00:11:04.591 --> 00:11:06.359 can be very, very slow. NOTE Paragraph 00:11:07.267 --> 00:11:10.616 But in our case, this really paid off this one time. 00:11:10.640 --> 00:11:14.918 We discovered that, literally, tons of carbon dioxide 00:11:14.942 --> 00:11:18.125 were coming out of this deeply buried oceanic plate. 00:11:18.149 --> 00:11:20.498 And the thing that was keeping them underground 00:11:20.522 --> 00:11:23.517 and keeping it from being released out into the atmosphere 00:11:23.541 --> 00:11:25.101 was that deep underground, 00:11:25.125 --> 00:11:29.109 underneath all the adorable sloths and toucans of Costa Rica, 00:11:29.133 --> 00:11:30.933 were chemolithoautotrophes. 00:11:31.338 --> 00:11:34.839 These microbes and the chemical processes that were happening around them 00:11:34.863 --> 00:11:37.615 were converting this carbon dioxide into carbonate mineral 00:11:37.639 --> 00:11:39.567 and locking it up underground. NOTE Paragraph 00:11:39.591 --> 00:11:41.885 Which makes you wonder 00:11:41.909 --> 00:11:45.410 if these subsurface processes are so good at sucking up 00:11:45.434 --> 00:11:48.015 all the carbon dioxide coming from below them, 00:11:48.039 --> 00:11:50.499 could they also help us with a little carbon problem 00:11:50.523 --> 00:11:52.688 we've got going on up at the surface? 00:11:53.006 --> 00:11:57.331 Humans are releasing enough carbon dioxide into our atmosphere 00:11:57.355 --> 00:12:00.329 that we are decreasing the ability of our planet 00:12:00.353 --> 00:12:02.353 to support life as we know it. 00:12:02.704 --> 00:12:05.136 And scientists and engineers and entrepreneurs 00:12:05.160 --> 00:12:07.664 are working on methods to pull carbon dioxide 00:12:07.688 --> 00:12:08.981 out of these point sources, 00:12:09.005 --> 00:12:11.323 so that they're not released into the atmosphere. 00:12:11.347 --> 00:12:12.998 And they need to put it somewhere. 00:12:13.022 --> 00:12:14.199 So for this reason, 00:12:14.223 --> 00:12:17.561 we need to keep studying places where this carbon might be stored, 00:12:17.585 --> 00:12:19.879 possibly in the subsurface, 00:12:19.903 --> 00:12:22.546 to know what's going to happen to it when it goes there. NOTE Paragraph 00:12:22.570 --> 00:12:26.037 Will these deep subsurface microbes be a problem because they're too slow 00:12:26.061 --> 00:12:27.942 to actually keep anything down there? 00:12:27.966 --> 00:12:29.374 Or will they be helpful 00:12:29.398 --> 00:12:33.188 because they'll help covert all this stuff to solid carbonate minerals? 00:12:33.712 --> 00:12:36.132 If we can make such a big breakthrough 00:12:36.156 --> 00:12:38.542 just from one study that we did in Costa Rica, 00:12:38.566 --> 00:12:41.533 then imagine what else is waiting to be discovered down there. NOTE Paragraph 00:12:41.891 --> 00:12:47.556 This new field of geo-bio-chemistry or deep subsurface biology, 00:12:47.580 --> 00:12:49.121 or whatever you want to call it, 00:12:49.145 --> 00:12:50.982 is going to have huge implications, 00:12:51.006 --> 00:12:53.379 not just for mitigating climate change, 00:12:53.403 --> 00:12:57.275 but possibly for understanding how life and earth have coevolved, 00:12:57.613 --> 00:13:02.311 or finding new products that are useful for industrial or medical applications. 00:13:02.335 --> 00:13:04.597 Maybe even predicting earthquakes 00:13:04.621 --> 00:13:06.819 or finding life outside our planet. 00:13:06.843 --> 00:13:09.969 It could even help us understand the origin of life itself. NOTE Paragraph 00:13:10.827 --> 00:13:13.652 Fortunately, I don't have to do this by myself. 00:13:13.962 --> 00:13:17.287 I have amazing colleagues all over the world 00:13:17.311 --> 00:13:20.603 who are cracking into the mysteries of this deep subsurface world. 00:13:21.831 --> 00:13:26.641 And it may seem like life buried deep within the earth's crust 00:13:26.665 --> 00:13:30.639 is so far away from our daily experiences that it's kind of irrelevant. 00:13:31.363 --> 00:13:35.051 But the truth is that this weird slow life 00:13:35.075 --> 00:13:38.600 may actually have the answers to some of the greatest mysteries 00:13:38.624 --> 00:13:39.774 of life on Earth. NOTE Paragraph 00:13:40.225 --> 00:13:41.376 Thank you. NOTE Paragraph 00:13:41.400 --> 00:13:46.444 (Applause)