The secrets I find on the mysterious ocean floor | Laura Robinson | TEDxBrussels
-
0:04 - 0:07I wanted to start out by saying to you
-
0:07 - 0:10that my younger brother
is actually a journalist -
0:10 - 0:14and he's told me that he writes an article
in about an hour or so. -
0:14 - 0:15It gets posted online,
-
0:15 - 0:20and within that day about 100,000 people
might read that article. -
0:20 - 0:23I could spend maybe a couple of years
planning an expedition, -
0:23 - 0:26a couple more years writing that article,
-
0:26 - 0:31and if my article is very well received -
or perhaps very badly received - -
0:31 - 0:34it might be cited about a hundred times
over the next ten years. -
0:34 - 0:38So Im'never going to receive
the same statistics as my younger brother. -
0:38 - 0:42However, this afternoon
you're helping me to do a little better, -
0:42 - 0:44so thank you for your attention.
-
0:44 - 0:49(Applause)
-
0:49 - 0:52So, I hope anyhow you'll find
what I'm going to say very interesting. -
0:52 - 0:54I'm an ocean chemist.
-
0:54 - 0:56I look at the chemistry
of the ocean today. -
0:56 - 0:59I look at the chemistry
of the ocean in the past. -
0:59 - 1:01The way I look back in the past
-
1:01 - 1:04is by using the fossilized remains
of deepwater corals. -
1:04 - 1:07You can see an image of one
of these corals behind me. -
1:07 - 1:11It was collected from close to Antarctica,
thousands of meters below the sea, -
1:11 - 1:13so, very different
than the kinds of corals -
1:13 - 1:17you may have been lucky enough to see
if you've had a tropical holiday. -
1:17 - 1:19So I'm hoping that this talk will give you
-
1:19 - 1:21a four-dimensional view of the ocean.
-
1:21 - 1:26Two dimensions, such as this
beautiful two-dimensional image -
1:26 - 1:27of the sea surface temperature.
-
1:27 - 1:31This was taken using satellite,
so it's got tremendous spatial resolution. -
1:32 - 1:35The overall features are extremely
easy to understand. -
1:35 - 1:39The equatorial regions are warm
because there's more sunlight. -
1:39 - 1:42The polar regions are cold
because there's less sunlight. -
1:42 - 1:45And that allows big icecaps
to build up on Antarctica -
1:45 - 1:47and up in the Northern Hemisphere.
-
1:47 - 1:50If you plunge deep into the sea,
or even put your toes in the sea, -
1:50 - 1:52you know it gets colder as you go down,
-
1:52 - 1:56and that's mostly because the deep waters
that fill the abyss of the ocean -
1:56 - 2:00come from the cold polar regions
where the waters are dense. -
2:01 - 2:04If we travel back in time
20,000 years ago, -
2:04 - 2:06the earth looked very much different.
-
2:06 - 2:10And I've just given you a cartoon version
of one of the major differences -
2:10 - 2:12you would have seen
if you went back that long. -
2:12 - 2:14The icecaps were much bigger.
-
2:14 - 2:17They covered lots of the continent,
and they extended out over the ocean. -
2:17 - 2:20Sea level was 120 meters lower.
-
2:20 - 2:24Carbon dioxide [levels] were very
much lower than they are today. -
2:24 - 2:27So the earth was probably about three
to five degrees colder overall, -
2:27 - 2:30and much, much colder
in the polar regions. -
2:32 - 2:33What I'm trying to understand,
-
2:33 - 2:36and what other colleagues of mine
are trying to understand, -
2:36 - 2:39is how we moved from that
cold climate condition -
2:39 - 2:42to the warm climate condition
that we enjoy today. -
2:42 - 2:44We know from ice core research -
-
2:44 - 2:46and in fact this is a picture
of an iceberg -
2:46 - 2:48taken by one of my colleagues,
Dann Blackwood, -
2:48 - 2:50down in the Southern Ocean -
-
2:50 - 2:53that the transition from these
cold conditions to warm conditions -
2:53 - 2:58wasn't smooth, as you might predict
from the slow increase in solar radiation. -
2:58 - 3:02And we know this from ice cores,
because if you drill down into ice, -
3:02 - 3:05you find annual bands of ice,
and you can see this in the iceberg. -
3:05 - 3:07You can see those blue-white layers.
-
3:07 - 3:11Gases are trapped in the ice cores,
so we can measure CO2 -- -
3:11 - 3:13that's why we know CO2
was lower in the past -- -
3:13 - 3:16and the chemistry of the ice
also tells us about temperature -
3:16 - 3:18in the polar regions.
-
3:18 - 3:21And if you move in time
from 20,000 years ago to the modern day, -
3:21 - 3:23you see that temperature increased.
-
3:23 - 3:25It didn't increase smoothly.
-
3:25 - 3:27Sometimes it increased very rapidly,
-
3:27 - 3:28then there was a plateau,
-
3:28 - 3:29then it increased rapidly.
-
3:29 - 3:31It was different in the two polar regions,
-
3:31 - 3:34and CO2 also increased in jumps.
-
3:35 - 3:38So we're pretty sure the ocean
has a lot to do with this. -
3:38 - 3:41The ocean stores huge amounts of carbon,
-
3:41 - 3:43about 60 times more
than is in the atmosphere. -
3:43 - 3:46It also acts to transport heat
across the equator, -
3:46 - 3:50and the ocean is full of nutrients
and it controls primary productivity. -
3:52 - 3:56So if we want to get down and find out
what's going on down in the deep sea, -
3:56 - 3:57we really need to get down there,
-
3:57 - 3:59see what's there
-
3:59 - 4:00and start to explore.
-
4:00 - 4:03This is some spectacular footage
coming from a seamount -
4:03 - 4:05about a kilometer deep
in international waters -
4:05 - 4:08in the equatorial Atlantic, far from land.
-
4:08 - 4:11You're amongst the first people
to see this bit of the seafloor, -
4:11 - 4:13along with my research team.
-
4:14 - 4:16You're probably seeing new species.
-
4:16 - 4:17We don't know.
-
4:17 - 4:21You'd have to collect the samples
and do some very intense taxonomy. -
4:21 - 4:23You can see beautiful bubblegum corals.
-
4:23 - 4:25There are brittle stars
growing on these corals. -
4:25 - 4:28Those are things that look
like tentacles coming out of corals. -
4:28 - 4:31There are corals made of different forms
of calcium carbonate -
4:31 - 4:35growing off the basalt of this
massive undersea mountain, -
4:35 - 4:39and the dark sort of stuff,
those are fossilized corals, -
4:39 - 4:41and we're going to talk
a little more about those -
4:41 - 4:43as we travel back in time.
-
4:43 - 4:45To do that, we need
to charter a research boat. -
4:45 - 4:48This is the James Cook,
an ocean-class research vessel -
4:49 - 4:50moored up in Tenerife.
-
4:50 - 4:51Looks beautiful, right?
-
4:51 - 4:53Great, if you're not a great mariner.
-
4:54 - 4:56Sometimes it looks
a little more like this. -
4:56 - 4:59This is us trying to make sure
that we don't lose precious samples. -
4:59 - 5:02Everyone's scurrying around,
and I get terribly seasick, -
5:02 - 5:05so it's not always a lot of fun,
but overall it is. -
5:06 - 5:09So we've got to become
a really good mapper to do this. -
5:09 - 5:13You don't see that kind of spectacular
coral abundance everywhere. -
5:13 - 5:16It is global and it is deep,
-
5:16 - 5:18but we need to really find
the right places. -
5:18 - 5:22We just saw a global map,
and overlaid was our cruise passage -
5:22 - 5:23from last year.
-
5:23 - 5:25This was a seven-week cruise,
-
5:25 - 5:27and this is us, having made our own maps
-
5:27 - 5:31of about 75,000 square kilometers
of the seafloor in seven weeks, -
5:31 - 5:33but that's only a tiny fraction
of the seafloor. -
5:33 - 5:35We're traveling from west to east,
-
5:35 - 5:39over part of the ocean that would
look featureless on a big-scale map, -
5:39 - 5:42but actually some of these mountains
are as big as Everest. -
5:43 - 5:45So with the maps that we make on board,
-
5:45 - 5:47we get about 100-meter resolution,
-
5:47 - 5:49enough to pick out areas
to deploy our equipment, -
5:49 - 5:51but not enough to see very much.
-
5:51 - 5:54To do that, we need to fly
remotely-operated vehicles -
5:54 - 5:56about five meters off the seafloor.
-
5:56 - 6:00And if we do that, we can get maps
that are one-meter resolution -
6:00 - 6:02down thousands of meters.
-
6:02 - 6:04Here is a remotely-operated vehicle,
-
6:04 - 6:06a research-grade vehicle.
-
6:06 - 6:09You can see an array
of big lights on the top. -
6:09 - 6:12There are high-definition cameras,
manipulator arms, -
6:12 - 6:15and lots of little boxes and things
to put your samples. -
6:15 - 6:19Here we are on our first dive
of this particular cruise, -
6:19 - 6:21plunging down into the ocean.
-
6:21 - 6:24We go pretty fast to make sure
the remotely operated vehicles -
6:24 - 6:27are not affected by any other ships -
parts of the ship. -
6:27 - 6:30You can see the bubbles going,
I quite like that footage. -
6:30 - 6:31And we go down,
-
6:31 - 6:33and these are the kinds of things you see.
-
6:34 - 6:37These are deep sea sponges, meter scale.
-
6:38 - 6:42This is a swimming holothurian --
it's a small sea slug, basically. -
6:42 - 6:43This is slowed down.
-
6:43 - 6:45Most of the footage I'm showing
you is speeded up, -
6:46 - 6:47because all of this takes a lot of time.
-
6:48 - 6:51This is a beautiful holothurian as well.
-
6:52 - 6:55And this animal you're going to see
coming up was a big surprise. -
6:55 - 6:58I've never seen anything like this
and it took us all a bit surprised. -
6:58 - 7:02This was after about 15 hours of work
and we were all a bit trigger-happy, -
7:02 - 7:04and suddenly this giant
sea monster started rolling past. -
7:05 - 7:08It's called a pyrosome
or colonial tunicate, if you like. -
7:08 - 7:10This wasn't what we were looking for.
-
7:10 - 7:12We were looking for corals,
deep sea corals. -
7:13 - 7:15You're going to see a picture
of one in a moment. -
7:15 - 7:18It's small, about five centimeters high.
-
7:18 - 7:21It's made of calcium carbonate,
so you can see its tentacles there, -
7:21 - 7:23moving in the ocean currents.
-
7:24 - 7:27An organism like this probably lives
for about a hundred years. -
7:27 - 7:31And as it grows, it takes in
chemicals from the ocean. -
7:31 - 7:33And the chemicals,
or the amount of chemicals, -
7:33 - 7:36depends on the temperature;
it depends on the pH, -
7:36 - 7:37it depends on the nutrients.
-
7:37 - 7:40And if we can understand how
these chemicals get into the skeleton, -
7:40 - 7:43we can then go back,
collect fossil specimens, -
7:43 - 7:46and reconstruct what the ocean
used to look like in the past. -
7:46 - 7:50And here you can see us collecting
that coral with a vacuum system, -
7:50 - 7:51pull it up,
-
7:51 - 7:54and we put it into a sampling container.
-
7:54 - 7:56We can do this very
carefully, I should add. -
7:58 - 8:01Some of these organisms live even longer.
-
8:01 - 8:04This is a black coral called Leiopathes,
an image taken by my colleague, -
8:04 - 8:07Brendan Roark, about 500
meters below Hawaii. -
8:08 - 8:10Four thousand years is a long time.
-
8:11 - 8:14If you take a branch from one
of these corals and polish it up, -
8:14 - 8:16this is about 100 microns across.
-
8:16 - 8:19And Brendan took some analyses
across this coral -- -
8:19 - 8:21you can see the marks --
-
8:21 - 8:24and he's been able to show
that these are actual annual bands, -
8:24 - 8:26so even at 500 meters deep in the ocean,
-
8:26 - 8:28corals can record seasonal changes,
-
8:29 - 8:30which is pretty spectacular.
-
8:30 - 8:34But 4,000 years is not enough to get
us back to our last glacial maximum. -
8:34 - 8:35So what do we do?
-
8:35 - 8:37We go in for these fossil specimens.
-
8:38 - 8:41This is what makes me really unpopular
with my research team. -
8:41 - 8:42So going along,
-
8:42 - 8:44there's giant sharks everywhere,
-
8:44 - 8:46there are pyrosomes,
there are swimming holothurians, -
8:46 - 8:47there's giant sponges,
-
8:47 - 8:50but I make everyone go down
to these dead fossil areas -
8:50 - 8:54and spend ages kind of shoveling
around on the seafloor. -
8:54 - 8:57And we pick up all these corals,
bring them back, we sort them out. -
8:57 - 8:59But each one of these is a different age,
-
8:59 - 9:01and if we can find out how old they are
-
9:01 - 9:04and then we can measure
those chemical signals, -
9:04 - 9:05this helps us to find out
-
9:05 - 9:08what's been going on
in the ocean in the past. -
9:08 - 9:10So on the left-hand image here,
-
9:10 - 9:13I've taken a slice through a coral,
polished it very carefully -
9:13 - 9:15and taken an optical image.
-
9:15 - 9:16On the right-hand side,
-
9:16 - 9:19we've taken that same piece of coral,
put it in a nuclear reactor, -
9:19 - 9:20induced fission,
-
9:21 - 9:22and every time there's some decay,
-
9:22 - 9:24you can see that marked out in the coral,
-
9:24 - 9:26so we can see the uranium distribution.
-
9:26 - 9:27Why are we doing this?
-
9:27 - 9:30Uranium is a very poorly regarded element,
-
9:30 - 9:31but I love it.
-
9:31 - 9:34The decay helps us find out
about the rates and dates -
9:34 - 9:36of what's going on in the ocean.
-
9:36 - 9:37And if you remember from the beginning,
-
9:37 - 9:40that's what we want to get at
when we're thinking about climate. -
9:41 - 9:42So we use a laser to analyze uranium
-
9:42 - 9:45and one of its daughter products,
thorium, in these corals, -
9:45 - 9:48and that tells us exactly
how old the fossils are. -
9:49 - 9:52This beautiful animation
of the Southern Ocean -
9:52 - 9:55I'm just going to use illustrate
how we're using these corals -
9:55 - 9:59to get at some of the ancient
ocean feedbacks. -
9:59 - 10:01You can see the density
of the surface water -
10:01 - 10:04in this animation by Ryan Abernathey.
-
10:05 - 10:07It's just one year of data,
-
10:07 - 10:09but you can see how dynamic
the Southern Ocean is. -
10:10 - 10:14The intense mixing,
particularly the Great Passage, -
10:14 - 10:17which is shown by the box,
-
10:17 - 10:20is really one of the strongest
currents in the world -
10:20 - 10:22coming through here,
flowing from west to east. -
10:22 - 10:23It's very turbulently mixed,
-
10:23 - 10:26because it's moving over those
great big undersea mountains, -
10:26 - 10:31and this allows CO2 and heat to exchange
with the atmosphere in and out. -
10:31 - 10:34And essentially, the oceans are breathing
through the Southern Ocean. -
10:35 - 10:41We've collected corals from back and forth
across this Antarctic passage, -
10:41 - 10:44and we've found quite a surprising thing
from my uranium dating: -
10:44 - 10:47the corals migrated from south to north
-
10:47 - 10:50during this transition from the glacial
to the interglacial. -
10:50 - 10:51We don't really know why,
-
10:51 - 10:53but we think it's something
to do with the food source -
10:53 - 10:55and maybe the oxygen in the water.
-
10:58 - 10:58So here we are.
-
10:58 - 11:02I'm going to illustrate what I think
we've found about climate -
11:02 - 11:04from those corals in the Southern Ocean.
-
11:04 - 11:07We went up and down sea mountains.
We collected little fossil corals. -
11:07 - 11:08This is my illustration of that.
-
11:08 - 11:10We think back in the glacial,
-
11:10 - 11:12from the analysis
we've made in the corals, -
11:12 - 11:15that the deep part of the Southern Ocean
was very rich in carbon, -
11:15 - 11:18and there was a low-density
layer sitting on top. -
11:18 - 11:21That stops carbon dioxide
coming out of the ocean. -
11:22 - 11:24We then found corals
that are of an intermediate age, -
11:24 - 11:29and they show us that the ocean mixed
partway through that climate transition. -
11:29 - 11:31That allows carbon to come
out of the deep ocean. -
11:32 - 11:35And then if we analyze corals
closer to the modern day, -
11:35 - 11:37or indeed if we go down there today anyway
-
11:37 - 11:40and measure the chemistry of the corals,
-
11:40 - 11:44we see that we move to a position
where carbon can exchange in and out. -
11:44 - 11:46So this is the way
we can use fossil corals -
11:46 - 11:48to help us learn about the environment.
-
11:50 - 11:52So I want to leave you
with this last slide. -
11:52 - 11:56It's just a still taken out of that first
piece of footage that I showed you. -
11:56 - 11:58This is a spectacular coral garden.
-
11:58 - 12:00We didn't even expect
to find things this beautiful. -
12:00 - 12:02It's thousands of meters deep.
-
12:02 - 12:04There are new species.
-
12:04 - 12:06It's just a beautiful place.
-
12:06 - 12:08There are fossils in amongst,
-
12:08 - 12:10and now I've trained you
to appreciate the fossil corals -
12:10 - 12:11that are down there.
-
12:11 - 12:14So next time you're lucky enough
to fly over the ocean -
12:14 - 12:16or sail over the ocean,
-
12:16 - 12:18just think -- there are massive
sea mountains down there -
12:19 - 12:20that nobody's ever seen before,
-
12:20 - 12:22and there are beautiful corals.
-
12:22 - 12:23Thank you.
-
12:23 - 12:28(Applause)
- Title:
- The secrets I find on the mysterious ocean floor | Laura Robinson | TEDxBrussels
- Description:
-
This talk was given at a local TEDx event, produced independently of the TED Conferences.
Hundreds of meters below the surface of the ocean, Laura Robinson probes the steep slopes of massive undersea mountains. She's on the hunt for thousand-year-old corals that she can test in a nuclear reactor to discover how the ocean changes over time. By studying the history of the earth, Robinson hopes to find clues of what might happen in the future.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDxTalks
- Duration:
- 12:31
Ivana Korom edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels | ||
TED Translators admin edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels | ||
TED Translators admin edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels | ||
TED Translators admin edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels | ||
TED Translators admin edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels | ||
TED Translators admin edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels | ||
TED Translators admin edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels | ||
TED Translators admin edited English subtitles for Hidden reefs of the deep sea | Laura Robinson | TEDxBrussels |