0:00:00.746,0:00:02.199 Well, I'm an ocean chemist. 0:00:02.223,0:00:04.342 I look at the chemistry[br]of the ocean today. 0:00:04.366,0:00:07.366 I look at the chemistry[br]of the ocean in the past. 0:00:07.390,0:00:09.454 The way I look back in the past 0:00:09.478,0:00:12.629 is by using the fossilized remains[br]of deepwater corals. 0:00:12.653,0:00:15.295 You can see an image of one[br]of these corals behind me. 0:00:15.319,0:00:19.745 It was collected from close to Antarctica,[br]thousands of meters below the sea, 0:00:19.769,0:00:21.857 so, very different[br]than the kinds of corals 0:00:21.881,0:00:25.668 you may have been lucky enough to see[br]if you've had a tropical holiday. 0:00:25.692,0:00:27.748 So I'm hoping that this talk will give you 0:00:27.772,0:00:29.565 a four-dimensional view of the ocean. 0:00:29.589,0:00:33.462 Two dimensions, such as this[br]beautiful two-dimensional image 0:00:33.486,0:00:35.080 of the sea surface temperature. 0:00:35.104,0:00:39.128 This was taken using satellite,[br]so it's got tremendous spatial resolution. 0:00:39.898,0:00:42.764 The overall features are extremely[br]easy to understand. 0:00:42.788,0:00:46.452 The equatorial regions are warm[br]because there's more sunlight. 0:00:46.476,0:00:49.162 The polar regions are cold[br]because there's less sunlight. 0:00:49.186,0:00:52.107 And that allows big icecaps[br]to build up on Antarctica 0:00:52.131,0:00:53.941 and up in the Northern Hemisphere. 0:00:54.299,0:00:57.717 If you plunge deep into the sea,[br]or even put your toes in the sea, 0:00:57.741,0:00:59.684 you know it gets colder as you go down, 0:00:59.708,0:01:03.687 and that's mostly because the deep waters[br]that fill the abyss of the ocean 0:01:03.711,0:01:06.876 come from the cold polar regions[br]where the waters are dense. 0:01:07.845,0:01:10.951 If we travel back in time[br]20,000 years ago, 0:01:10.975,0:01:12.835 the earth looked very much different. 0:01:12.859,0:01:16.326 And I've just given you a cartoon version[br]of one of the major differences 0:01:16.350,0:01:18.605 you would have seen[br]if you went back that long. 0:01:18.629,0:01:20.311 The icecaps were much bigger. 0:01:20.335,0:01:23.962 They covered lots of the continent,[br]and they extended out over the ocean. 0:01:23.986,0:01:26.479 Sea level was 120 meters lower. 0:01:26.503,0:01:30.047 Carbon dioxide [levels] were very[br]much lower than they are today. 0:01:30.071,0:01:33.715 So the earth was probably about three[br]to five degrees colder overall, 0:01:33.739,0:01:36.559 and much, much colder[br]in the polar regions. 0:01:37.908,0:01:39.362 What I'm trying to understand, 0:01:39.386,0:01:42.188 and what other colleagues of mine[br]are trying to understand, 0:01:42.212,0:01:44.671 is how we moved from that[br]cold climate condition 0:01:44.695,0:01:47.591 to the warm climate condition[br]that we enjoy today. 0:01:47.615,0:01:49.674 We know from ice core research 0:01:49.698,0:01:52.778 that the transition from these[br]cold conditions to warm conditions 0:01:52.802,0:01:57.550 wasn't smooth, as you might predict[br]from the slow increase in solar radiation. 0:01:58.153,0:02:01.384 And we know this from ice cores,[br]because if you drill down into ice, 0:02:01.408,0:02:04.679 you find annual bands of ice,[br]and you can see this in the iceberg. 0:02:04.703,0:02:06.694 You can see those blue-white layers. 0:02:06.718,0:02:10.344 Gases are trapped in the ice cores,[br]so we can measure CO2 -- 0:02:10.368,0:02:12.733 that's why we know CO2[br]was lower in the past -- 0:02:12.757,0:02:15.750 and the chemistry of the ice[br]also tells us about temperature 0:02:15.774,0:02:17.249 in the polar regions. 0:02:17.273,0:02:20.952 And if you move in time[br]from 20,000 years ago to the modern day, 0:02:20.976,0:02:22.785 you see that temperature increased. 0:02:22.809,0:02:24.434 It didn't increase smoothly. 0:02:24.458,0:02:26.236 Sometimes it increased very rapidly, 0:02:26.260,0:02:27.504 then there was a plateau, 0:02:27.528,0:02:28.793 then it increased rapidly. 0:02:28.817,0:02:30.841 It was different in the two polar regions, 0:02:30.865,0:02:33.594 and CO2 also increased in jumps. 0:02:34.808,0:02:37.854 So we're pretty sure the ocean[br]has a lot to do with this. 0:02:37.878,0:02:40.244 The ocean stores huge amounts of carbon, 0:02:40.268,0:02:42.822 about 60 times more[br]than is in the atmosphere. 0:02:42.846,0:02:46.048 It also acts to transport heat[br]across the equator, 0:02:46.072,0:02:49.841 and the ocean is full of nutrients[br]and it controls primary productivity. 0:02:50.142,0:02:53.126 So if we want to find out[br]what's going on down in the deep sea, 0:02:53.150,0:02:54.743 we really need to get down there, 0:02:54.767,0:02:55.933 see what's there 0:02:55.957,0:02:57.361 and start to explore. 0:02:57.385,0:03:00.392 This is some spectacular footage[br]coming from a seamount 0:03:00.416,0:03:02.605 about a kilometer deep[br]in international waters 0:03:02.629,0:03:05.609 in the equatorial Atlantic, far from land. 0:03:05.633,0:03:08.682 You're amongst the first people[br]to see this bit of the seafloor, 0:03:08.706,0:03:10.348 along with my research team. 0:03:11.340,0:03:13.084 You're probably seeing new species. 0:03:13.108,0:03:14.260 We don't know. 0:03:14.284,0:03:17.944 You'd have to collect the samples[br]and do some very intense taxonomy. 0:03:17.968,0:03:19.861 You can see beautiful bubblegum corals. 0:03:19.885,0:03:22.139 There are brittle stars[br]growing on these corals. 0:03:22.163,0:03:25.219 Those are things that look[br]like tentacles coming out of corals. 0:03:25.243,0:03:28.115 There are corals made of different forms[br]of calcium carbonate 0:03:28.139,0:03:31.515 growing off the basalt of this[br]massive undersea mountain, 0:03:31.539,0:03:34.903 and the dark sort of stuff,[br]those are fossilized corals, 0:03:34.927,0:03:37.238 and we're going to talk[br]a little more about those 0:03:37.262,0:03:38.610 as we travel back in time. 0:03:39.030,0:03:41.515 To do that, we need[br]to charter a research boat. 0:03:41.539,0:03:44.579 This is the James Cook,[br]an ocean-class research vessel 0:03:44.603,0:03:45.873 moored up in Tenerife. 0:03:45.897,0:03:47.229 Looks beautiful, right? 0:03:47.554,0:03:49.384 Great, if you're not a great mariner. 0:03:49.702,0:03:52.206 Sometimes it looks[br]a little more like this. 0:03:52.230,0:03:55.429 This is us trying to make sure[br]that we don't lose precious samples. 0:03:55.453,0:03:58.270 Everyone's scurrying around,[br]and I get terribly seasick, 0:03:58.294,0:04:01.288 so it's not always a lot of fun,[br]but overall it is. 0:04:01.312,0:04:03.898 So we've got to become[br]a really good mapper to do this. 0:04:03.922,0:04:07.661 You don't see that kind of spectacular[br]coral abundance everywhere. 0:04:07.685,0:04:10.725 It is global and it is deep, 0:04:10.749,0:04:13.063 but we need to really find[br]the right places. 0:04:13.087,0:04:16.253 We just saw a global map,[br]and overlaid was our cruise passage 0:04:16.277,0:04:17.482 from last year. 0:04:17.990,0:04:19.386 This was a seven-week cruise, 0:04:19.410,0:04:21.434 and this is us, having made our own maps 0:04:21.458,0:04:25.529 of about 75,000 square kilometers[br]of the seafloor in seven weeks, 0:04:25.553,0:04:28.075 but that's only a tiny fraction[br]of the seafloor. 0:04:28.099,0:04:29.868 We're traveling from west to east, 0:04:29.892,0:04:33.392 over part of the ocean that would[br]look featureless on a big-scale map, 0:04:33.416,0:04:36.673 but actually some of these mountains[br]are as big as Everest. 0:04:36.697,0:04:38.626 So with the maps that we make on board, 0:04:38.650,0:04:40.642 we get about 100-meter resolution, 0:04:40.666,0:04:43.555 enough to pick out areas[br]to deploy our equipment, 0:04:43.579,0:04:45.493 but not enough to see very much. 0:04:45.517,0:04:48.239 To do that, we need to fly[br]remotely-operated vehicles 0:04:48.263,0:04:50.477 about five meters off the seafloor. 0:04:50.501,0:04:53.716 And if we do that, we can get maps[br]that are one-meter resolution 0:04:53.740,0:04:55.834 down thousands of meters. 0:04:55.858,0:04:57.675 Here is a remotely-operated vehicle, 0:04:57.699,0:05:00.010 a research-grade vehicle. 0:05:00.034,0:05:02.516 You can see an array[br]of big lights on the top. 0:05:02.540,0:05:05.595 There are high-definition cameras,[br]manipulator arms, 0:05:05.619,0:05:08.532 and lots of little boxes and things[br]to put your samples. 0:05:09.087,0:05:12.805 Here we are on our first dive[br]of this particular cruise, 0:05:12.829,0:05:14.535 plunging down into the ocean. 0:05:14.559,0:05:17.432 We go pretty fast to make sure[br]the remotely operated vehicles 0:05:17.456,0:05:19.179 are not affected by any other ships. 0:05:19.203,0:05:20.401 And we go down, 0:05:20.425,0:05:22.599 and these are the kinds of things you see. 0:05:22.623,0:05:26.123 These are deep sea sponges, meter scale. 0:05:26.817,0:05:31.065 This is a swimming holothurian --[br]it's a small sea slug, basically. 0:05:31.089,0:05:32.276 This is slowed down. 0:05:32.300,0:05:34.689 Most of the footage I'm showing[br]you is speeded up, 0:05:34.713,0:05:36.641 because all of this takes a lot of time. 0:05:37.474,0:05:40.413 This is a beautiful holothurian as well. 0:05:40.897,0:05:43.969 And this animal you're going to see[br]coming up was a big surprise. 0:05:43.993,0:05:47.405 I've never seen anything like this[br]and it took us all a bit surprised. 0:05:47.429,0:05:51.017 This was after about 15 hours of work[br]and we were all a bit trigger-happy, 0:05:51.041,0:05:53.778 and suddenly this giant[br]sea monster started rolling past. 0:05:53.802,0:05:56.908 It's called a pyrosome[br]or colonial tunicate, if you like. 0:05:56.932,0:05:58.719 This wasn't what we were looking for. 0:05:58.743,0:06:01.389 We were looking for corals,[br]deep sea corals. 0:06:02.194,0:06:04.492 You're going to see a picture[br]of one in a moment. 0:06:04.516,0:06:07.151 It's small, about five centimeters high. 0:06:07.175,0:06:10.493 It's made of calcium carbonate,[br]so you can see its tentacles there, 0:06:10.517,0:06:12.648 moving in the ocean currents. 0:06:13.180,0:06:16.291 An organism like this probably lives[br]for about a hundred years. 0:06:16.315,0:06:19.855 And as it grows, it takes in[br]chemicals from the ocean. 0:06:19.879,0:06:22.085 And the chemicals,[br]or the amount of chemicals, 0:06:22.109,0:06:24.783 depends on the temperature;[br]it depends on the pH, 0:06:24.807,0:06:26.353 it depends on the nutrients. 0:06:26.377,0:06:29.611 And if we can understand how[br]these chemicals get into the skeleton, 0:06:29.635,0:06:32.133 we can then go back,[br]collect fossil specimens, 0:06:32.157,0:06:35.301 and reconstruct what the ocean[br]used to look like in the past. 0:06:35.325,0:06:38.761 And here you can see us collecting[br]that coral with a vacuum system, 0:06:38.785,0:06:41.386 and we put it into a sampling container. 0:06:41.410,0:06:43.469 We can do this very[br]carefully, I should add. 0:06:43.493,0:06:45.878 Some of these organisms live even longer. 0:06:45.902,0:06:49.304 This is a black coral called Leiopathes,[br]an image taken by my colleague, 0:06:49.328,0:06:52.590 Brendan Roark, about 500[br]meters below Hawaii. 0:06:52.614,0:06:54.657 Four thousand years is a long time. 0:06:54.962,0:06:58.097 If you take a branch from one[br]of these corals and polish it up, 0:06:58.121,0:07:00.414 this is about 100 microns across. 0:07:00.763,0:07:03.254 And Brendan took some analyses[br]across this coral -- 0:07:03.278,0:07:05.084 you can see the marks -- 0:07:05.108,0:07:08.067 and he's been able to show[br]that these are actual annual bands, 0:07:08.091,0:07:10.004 so even at 500 meters deep in the ocean, 0:07:10.028,0:07:12.796 corals can record seasonal changes, 0:07:12.820,0:07:14.552 which is pretty spectacular. 0:07:14.576,0:07:18.374 But 4,000 years is not enough to get[br]us back to our last glacial maximum. 0:07:18.398,0:07:19.556 So what do we do? 0:07:19.580,0:07:21.587 We go in for these fossil specimens. 0:07:22.180,0:07:25.111 This is what makes me really unpopular[br]with my research team. 0:07:25.135,0:07:26.285 So going along, 0:07:26.309,0:07:27.927 there's giant sharks everywhere, 0:07:27.951,0:07:30.449 there are pyrosomes,[br]there are swimming holothurians, 0:07:30.473,0:07:31.744 there's giant sponges, 0:07:31.768,0:07:34.363 but I make everyone go down[br]to these dead fossil areas 0:07:34.387,0:07:37.943 and spend ages kind of shoveling[br]around on the seafloor. 0:07:37.967,0:07:41.332 And we pick up all these corals,[br]bring them back, we sort them out. 0:07:41.356,0:07:43.651 But each one of these is a different age, 0:07:43.675,0:07:45.576 and if we can find out how old they are 0:07:45.600,0:07:48.112 and then we can measure[br]those chemical signals, 0:07:48.136,0:07:49.558 this helps us to find out 0:07:49.582,0:07:52.065 what's been going on[br]in the ocean in the past. 0:07:52.558,0:07:54.262 So on the left-hand image here, 0:07:54.286,0:07:57.318 I've taken a slice through a coral,[br]polished it very carefully 0:07:57.342,0:07:59.312 and taken an optical image. 0:07:59.336,0:08:00.488 On the right-hand side, 0:08:00.512,0:08:03.612 we've taken that same piece of coral,[br]put it in a nuclear reactor, 0:08:03.636,0:08:04.788 induced fission, 0:08:04.812,0:08:06.443 and every time there's some decay, 0:08:06.467,0:08:08.449 you can see that marked out in the coral, 0:08:08.473,0:08:10.362 so we can see the uranium distribution. 0:08:10.386,0:08:11.537 Why are we doing this? 0:08:11.561,0:08:13.848 Uranium is a very poorly regarded element, 0:08:13.872,0:08:15.031 but I love it. 0:08:15.055,0:08:18.267 The decay helps us find out[br]about the rates and dates 0:08:18.291,0:08:19.830 of what's going on in the ocean. 0:08:19.854,0:08:21.752 And if you remember from the beginning, 0:08:21.776,0:08:24.789 that's what we want to get at[br]when we're thinking about climate. 0:08:24.813,0:08:26.564 So we use a laser to analyze uranium 0:08:26.588,0:08:29.373 and one of its daughter products,[br]thorium, in these corals, 0:08:29.397,0:08:32.036 and that tells us exactly[br]how old the fossils are. 0:08:32.742,0:08:34.934 This beautiful animation[br]of the Southern Ocean 0:08:34.958,0:08:38.093 I'm just going to use illustrate[br]how we're using these corals 0:08:38.117,0:08:42.188 to get at some of the ancient[br]ocean feedbacks. 0:08:42.212,0:08:44.638 You can see the density[br]of the surface water 0:08:44.662,0:08:47.060 in this animation by Ryan Abernathey. 0:08:47.481,0:08:49.518 It's just one year of data, 0:08:49.542,0:08:52.152 but you can see how dynamic[br]the Southern Ocean is. 0:08:52.500,0:08:55.907 The intense mixing,[br]particularly the Drake Passage, 0:08:55.931,0:08:58.368 which is shown by the box, 0:08:58.392,0:09:01.004 is really one of the strongest[br]currents in the world 0:09:01.028,0:09:03.235 coming through here,[br]flowing from west to east. 0:09:03.259,0:09:04.608 It's very turbulently mixed, 0:09:04.632,0:09:07.504 because it's moving over those[br]great big undersea mountains, 0:09:07.528,0:09:12.009 and this allows CO2 and heat to exchange[br]with the atmosphere in and out. 0:09:12.033,0:09:15.540 And essentially, the oceans are breathing[br]through the Southern Ocean. 0:09:16.865,0:09:22.329 We've collected corals from back and forth[br]across this Antarctic passage, 0:09:22.353,0:09:25.380 and we've found quite a surprising thing[br]from my uranium dating: 0:09:25.404,0:09:27.907 the corals migrated from south to north 0:09:27.931,0:09:31.060 during this transition from the glacial[br]to the interglacial. 0:09:31.084,0:09:32.291 We don't really know why, 0:09:32.315,0:09:34.864 but we think it's something[br]to do with the food source 0:09:34.888,0:09:36.845 and maybe the oxygen in the water. 0:09:37.718,0:09:38.873 So here we are. 0:09:38.897,0:09:41.945 I'm going to illustrate what I think[br]we've found about climate 0:09:41.969,0:09:43.929 from those corals in the Southern Ocean. 0:09:43.953,0:09:47.228 We went up and down sea mountains.[br]We collected little fossil corals. 0:09:47.252,0:09:48.778 This is my illustration of that. 0:09:48.802,0:09:50.207 We think back in the glacial, 0:09:50.231,0:09:52.254 from the analysis[br]we've made in the corals, 0:09:52.278,0:09:55.364 that the deep part of the Southern Ocean[br]was very rich in carbon, 0:09:55.388,0:09:58.077 and there was a low-density[br]layer sitting on top. 0:09:58.101,0:10:00.894 That stops carbon dioxide[br]coming out of the ocean. 0:10:01.752,0:10:04.344 We then found corals[br]that are of an intermediate age, 0:10:04.368,0:10:08.948 and they show us that the ocean mixed[br]partway through that climate transition. 0:10:08.972,0:10:11.439 That allows carbon to come[br]out of the deep ocean. 0:10:12.154,0:10:15.253 And then if we analyze corals[br]closer to the modern day, 0:10:15.277,0:10:17.531 or indeed if we go down there today anyway 0:10:17.555,0:10:19.761 and measure the chemistry of the corals, 0:10:19.785,0:10:23.779 we see that we move to a position[br]where carbon can exchange in and out. 0:10:23.803,0:10:25.877 So this is the way[br]we can use fossil corals 0:10:25.901,0:10:27.843 to help us learn about the environment. 0:10:29.827,0:10:31.961 So I want to leave you[br]with this last slide. 0:10:31.985,0:10:35.908 It's just a still taken out of that first[br]piece of footage that I showed you. 0:10:35.932,0:10:38.044 This is a spectacular coral garden. 0:10:38.068,0:10:40.626 We didn't even expect[br]to find things this beautiful. 0:10:40.650,0:10:42.534 It's thousands of meters deep. 0:10:42.558,0:10:43.932 There are new species. 0:10:44.416,0:10:46.315 It's just a beautiful place. 0:10:46.339,0:10:47.720 There are fossils in amongst, 0:10:47.744,0:10:50.435 and now I've trained you[br]to appreciate the fossil corals 0:10:50.459,0:10:51.674 that are down there. 0:10:51.698,0:10:54.564 So next time you're lucky enough[br]to fly over the ocean 0:10:54.588,0:10:55.997 or sail over the ocean, 0:10:56.021,0:10:58.688 just think -- there are massive[br]sea mountains down there 0:10:58.712,0:11:00.579 that nobody's ever seen before, 0:11:00.603,0:11:02.220 and there are beautiful corals. 0:11:02.244,0:11:03.395 Thank you. 0:11:03.419,0:11:08.349 (Applause)