The Royal Institution Christmas Lectures (2010) - full transcript

When you dive through the waves, you
enter another world, our ocean.

This giant pool of liquid water covers
70% of the Earth's surface

and on average, it's 4km deep.

And down here, the rules are
different.

You can move freely in any direction.

You can live an entire lifetime and
you never see the sun.

And at night, jellyfish like this rise
up through this alien world

to hunt near the surface at night.

And as the Earth turns, the jellyfish
go back down

and this dark water is lit by our star

to form the blue of our Blue Planet.



In this lecture, we're going to be
looking at

that ocean engine and its impact on
our lives and our climate.

The jellyfish are just the tiniest
hints of the beautiful complexity

that's hidden down there.

APPLAUSE

Hello and welcome to the Royal
Institution Christmas Lectures,

and a special welcome to the virtual
audience who are joining us

from homes and schools across the UK
and Ireland.

I'm Dr Helen Czerski

and I'm an ocean physicist from
University College London.

And this is Planet Earth.

And we don't often see this view of
it, we're looking down

at the Pacific and this gigantic ocean
covers an entire third

of the Earth's surface.



We often talk about Earth as a Blue
Planet, but this is why -

there's so much of it.

There was a famous science fiction
writer called Arthur C Clarke,

who once said, "How inappropriate to
call this planet Earth

"when it's so clearly ocean."

And I tend to agree with him.

So here are the familiar continents,
the ones we live on,

and we can now see that they're just
part of this ocean world.

We learned in Chris' lecture that it's
the workings of the Earth's

system that determine the climate and
the habitability

of our home planet.

And what we'll learn is that the ocean
is at the heart

of that life support system.

We're all living in the oceans'
shadow, whether we know it or not.

And I am an unashamed ocean
enthusiast.

I think it's the most amazing feature
of our planet.

And I'm hoping that today I'm going to
convince you all

to join the ocean fan club.

And the ocean may seem sometimes like
an alien world,

but it is essential for everything we
take for granted.

So we have so much to explore.

We've got the world's largest
waterfall,

the version of a rainforest that you
get in the ocean,

what the bubbles are really up to

and quite a lot of poo because it's
very important.

But first of all, we want to know
something about where we're going.

And we knew very little about the
oceans, really,

until this ship came along, the HMS
Challenger.

And in the 1870s, this ship went on an
enormous

four-year voyage around the oceans.

They covered 79,000 miles.

They studied everything they could
find about the ocean.

And this, this was the birth of
oceanography.

So just imagine setting out on that
expedition.

What do you know about where you're
going?

Well, not very much and if we look at
the map here,

this is kind of a representation of
the knowledge of the ocean.

So we know where the coasts are.

So we can see there's North America
and South America,

there's Africa over here, we can see
Australia.

So we know what shape the edges of the
ocean are.

But everything in the middle, that's
just hidden,

it's unknown knowledge.

Well, Challenger started to map the
anatomy of the ocean

with a very simple measure, it
measured temperature.

Erm... It's just one of the
measurements that they made.

And the thing about a ship is, it can
only go to one place

and it can collect data in that one
place.

So let's uncover some of the ocean
knowledge here.

And what we're looking for is
temperatures,

let's peg a sample here.

So we've uncovered, we've got a water
sample,

we've uncovered a part of the ocean
and we can see underneath

that this is red, so this is telling
us that the ocean here

is really warm, it's about 30 degrees.

So let's take our ship somewhere else.

We can take another sample over here,
perhaps?

And this one, this one's purply blue.

So we've uncovered a bit of ocean
knowledge that the water here

is perhaps minus two, nearly minus
two, so it's really cold.

And perhaps one more over here.

So you can see... That's what's going
on here.

So we've got green underneath here, so
our water sample here

is 15 degrees.

But you can see that this is a really
slow way

of mapping the ocean.

So for 100 years after Challenger,

ships went out in the ocean, but when
they measured

surface temperature, basically they
were colouring in

this map of ocean temperature, one
tiny dot at a time.

You need a lot of patience to do that,
but it is all we had.

And the problem with ships is, they're
big and expensive

and they have to come home sometimes.

So if we really want to find out, we
want to find this knowledge,

the temperature knowledge of the
ocean,

how about sending something that
doesn't need to come home?

Well, this is an Argo float, this is
one of the things

that can do that and these are buoys
that can float

around the ocean and at the moment,
right now,

there are 4,000 of them, nearly 4,000,
floating around the ocean.

We can see them here.

So each one of these little dots is a
track of one of these drifters.

And what they do is they go down in
the ocean

to one kilometre's depth.

They just drift wherever the ocean
takes them and then they go down

to 2km and then all the way back up to
the surface

and they're measuring along the way.

And the antenna on the top here then
sends that data home

and then the drifter, the Argo float,
goes back down and carries on

wherever the ocean can take it.

So these are telling us not just about
the surface, but also

about the interior of the ocean.

But it's still not really colouring in
on map of the surface

ocean really quickly.

We can still only measure in a few
small points.

So our knowledge of the temperature of
the ocean didn't really change

until satellite technology and
computing power came along.

So we're going to uncover the map of
surface temperature

with this thing here.

So what we want is a countdown from
everyone,

to uncover this temperature map.

So here we go.

ALL:
- Three, two, one.

- OK, so now we can see what
Challenger couldn't,

we can see how much detail there is
down here.

And the colours here represent
temperatures, so we can see

the warmest water is this red along
the equator.

That's probably what we expect - nice
warm water at the equator.

And then closer to the poles, we've
got bluey-purple on the map,

so that means water that's much closer
to the freezing point.

But then look at all the detail in
between.

So, for example, here we can see the
Gulf Stream coming up the coast

of America, this warm water stretching
up the coast here.

And then if we look a bit further down
now,

once we really get to zoom in on the
detail,

we start to see patterns that we don't
expect.

Down here, for example, we can see on
either coast of Africa

at the same latitude, there's cold
water on this side

and warm water on that side.

And then when we really look at all
these details,

there's all these beautiful swirls,

this is a work of art written in
temperature.

There's an astonishing amount going
on.

What this is telling us is that all
that water in the ocean

that looks the same isn't the same.

It has anatomy, it has structure.

And we're starting to see with this
temperature map

what that structure looks like.

So, it's time to dive down into the
ocean.

And for all I love the ocean,

I really hate cold water,

so I'm going to pick somewhere nice
and warm, up here.

So, in the Gulf of Mexico here, it's
lovely and warm.

It's got surface temperature of about
28 degrees C,

so that - nicely tropical, that's what
we want.

So, that's where I'm going to go
exploring.

So, let's imagine sinking down into
the ocean at that spot.

We're leaving the waves behind and
it's becoming murky and gloomy

as the sunlight disappears.

And quite soon it's just dark.

And there's occasional spots of
bioluminescence.

And we're sinking down through the
ocean,

two kilometres to reach the sea floor

and then we land on the bottom.

So, what lives down here?

Well, in 2013, one of these was
discovered

at the bottom of the Gulf of Mexico,

and it's a really strange creature -
it's a shark.

They grow to about six metres long.

They live to around 400 years.

But the strangest thing of all about
finding this shark here

in the Gulf of Mexico is that this is
a Greenland shark.

It's a highly cold-adapted species

that normally lives in the Arctic
Ocean.

So, what's an Arctic shark doing in
the tropics?

That's a good question.

To answer that, we need to have a
think about salt.

So, if there's one thing that we know
about the ocean -

most people know about the ocean -
it's that the ocean is salty.

Oceanographers call that salinity.

So, saltiness and salinity are the
same thing.

But it's often easy to forget that the
ocean is salty

because all that salt is invisible.

Gemma here's got a bottle that's got
water

that's as salty as the ocean.

And you're going to let it go.

Go on.

And what we can see is that as the
drops hit this hotplate

the water is evaporating away
immediately,

and we can see it's leaving behind
salts

in these beautiful patterns here.

And the thing is that these are only
tiny drops

and they still contain enough salt for
us to see.

So, when it comes back to the whole
ocean,

how much salt is there down there and
what's it doing there?

Well, I've got a guest who's going to
help explain this.

SHE LAUGHS

What an entrance!

Chris, hello.

Why have you come to visit us in your
bath?

- Well, as you well know,

the Christmas Lectures are quite hard
work,

so I thought I'd have a relaxing,
freshwater bath,

but I heard a saltwater bath might be
even better for me.

- So, you have come to get some salt
for your bath?

- If that is possible, thank you, yes.

- Are you sure you want this bath to
be as salty as the ocean?

- I would love it to be as salty as
possible.

I think it'll have my skin, yeah.
- Right.

How much salt do you think you need?

- I think we need quite a lot.
- Quite a lot.
- Yeah.

Quite a lot, to cover me up at least.

- OK, well, let's start with this.

This is...

THEY LAUGH

We've got...
- It's actually really cold, by the
way!

- Welcome to oceanography.

It's often cold and miserable.

OK, so we're adding salt here. Is this
enough?

Do you really want this to be as salty
as the ocean?

- I need it to be salty as possible,
yeah. I love the sea.

- Are you committed to this?
- I'm fully committed.

- OK, right.

So, that's 8kg of salt.

That's how much salt you need to make
your bath

as salty as the ocean.

- Thank you, Helen!

- Right, why is there all this salt in
the ocean?

- So, rocks, like my pet rock here,
contain salt -

the ones that are exposed at the
Earth's surface -

so when the rivers run over those
rocks,

they dissolve the salt and deliver it
to your oceans.

- So, it's all to do with the rocks.

- Of course it's all to do with the
rocks!
- Yeah, yeah, yeah.

This is the ocean lecture!

OK, off you go. Enjoy your bath.
- Bye-bye.
- Thank you very much.

APPLAUSE

The anatomy of the ocean is written in
salt and temperature,

and now we know about those, we can
start to see why they matter.

And one of the things they do

is to create the largest waterfall in
the world.

So, let's come over to the map over
here.

We're going to go to a very specific
place on the globe.

We're going to look up here.

Let's come back, and here we can see
Greenland.

This is the North Atlantic and we've
got Iceland here.

So, this region is where we're going
to be looking.

But I want to show you what it really
looks like underwater,

because even in a really big storm,

the surface of the ocean is really
quite flat.

But, if we look underneath the
surface,

it doesn't look like that at all.

I've got this fabulous sandbox here.

Now just to orient you, so we looked
at that area on the map,

and in the sandbox Greenland is on
this side,

so the North Atlantic is stretching
down that way away from me.

Iceland is over here and I'm standing
in the Arctic right now.

So, this is all sea floor.

This is a really deep basin down here,

it's about two kilometres deep.

So, I'm going to walk around the other
side

and start digging because on this side
we've got the Atlantic,

so this is going to be quite a lot of
digging.

So, the ocean here is really deep.

It's going to go down to about three
or four kilometres

beneath the sea floor.

So, it's taking a bit of work here.

Greenland's getting a bit bigger in
the process.

Iceland's over there.

OK, so we're starting to see the shape
here now.

So, we've got - this is the North
Atlantic.

So, what we can see now is, first of
all,

that the sea floor has shape.

There's all this stuff going on,

even though we can't see it from the
surface.

There are mountains and valleys and
vast plains underwater

and they are enormous.

This is what we can see here, these
two massive basins.

And there's a ridge in between

stretching from Greenland to Iceland.

So, we're going to look at a line, a
cross section,

that goes through this bit here.

And we've got a model of it over here.

So, here's our cross section.

We've got the Arctic on this side

and this is the south where the
Atlantic is.

So, the first thing is that we can see
that all of this water in here,

it all looks the same, right? It's
just water.

Well, I'm going to add a little bit of
red food dye to it.

Just in the top here.

So what we can see

is that this red food dye is staying
at the surface

and there's a reason that it's staying
at the surface

because there are actually two layers
of water in here.

It's just that we couldn't see them
before.

If we look at this from the side,

what we can see is that there's this
warm layer,

a layer of warm water in here.

And the red dye has just showed you
where it is.

But underneath the water is a little
bit cooler.

And the thing that the temperature is
doing is

it's changing the buoyancy of the
water,

so that red warm water stays at the
top.

It doesn't mix with the water
underneath.

And that's why the ocean has
structure,

because it doesn't all just mix up.

So, now, Helen here's going to release
this cold water here.

So, this is Arctic water that's really
cold.

And we're going to have a look at what
it does.

And there it goes, cascading down to
the bottom.

So, this is cold, dense water

and it's flowing over the ridge

and it's filling up the basin over
here.

So, let's have a look at what this
means back on our model here.

Here we are. This is the Greenland Sea
up here.

This is the cold Arctic water,

and cold water from the Arctic is
flowing over this ridge

down into the North Atlantic,

and it's filling up the deep ocean
from underneath.

And this is the largest waterfall in
the world.

It's 3.5 kilometres high.

The amount of water going over it

is 200 times bigger than the largest
waterfall on land.

So, that's 5 million cubic metres
every second,

is pouring over this.

And the thing I love about this is
that sailors have been crossing

from Iceland to Greenland for
centuries and they've never known

that this enormous waterfall was just
underneath them.

But it's not just happening here.

Cold polar water is filling up the
deep ocean basins

all around the world.

So, this is the reason that the deep
ocean is actually really cold.

So, now we can get back to the
question

of that Greenland shark.

What was it doing in the Gulf of
Mexico?

And the reason it was there is that
the Gulf of Mexico,

really deep down, is filled up by cold
water from the poles

that stays at the bottom.

Where it was discovered, it was only
four degrees Celsius,

even though at the surface it was 28
degrees C.

So, we've got these two major layers
in the ocean.

We've got the warmer layer on top,

which is all of that beautiful surface
map that we saw before.

But most of the deep ocean basins are
filled up with cold water

that came originally from the poles.

That's a really important thing about
the structure of the ocean.

Now, I love maps, but they do annoy me
in one respect,

which is that they show the land as
being stationary -

which it is - that's all fine.

But they also show the ocean as being
still, and it really isn't.

It's moving.

If you remember those beautiful swirls
on the temperature patterns

at the start, it looks like they're
moving.

There's lots of energy there.

So, we're used to the idea of
atmospheric weather.

That's what happens when we go outside

and we get rained on or whatever.

What about the idea of ocean weather?

So, to talk to us about ocean weather,

please welcome Dr Eleanor
Frajka-Williams.
- Hello.

- Hello.

So, first of all, you can't join us in
person,

but you've got a very good excuse for
that. Tell us why that is.

- That's right. I'm isolating before
heading to sea next week.

- So, where will you be going?
- We'll be going to the Atlantic

between the Bahamas and Canary Islands

to measure how the ocean circulation
is changing.

- Well, ocean circulation is very
topical here.

So, we've got a demonstration here.

So, we have to remember that the Earth
is a rotating planet

and the ocean is just liquid sitting
on top of a rotating planet.

So, we've had water that's been
rotating,

and I'm going to put dye in.

Eleanor, as I put the dye in perhaps
you can tell us what you see.

- Yeah. So, as you put in the dye,

you can start to see how the ocean is
moving

and what you'll start to notice is
that it generates swirls

and filaments of dye, rather than just
a giant cloud of colour.

They spin up into what we see in the
real ocean and call eddies.

- So, the swirls we can see here are
caused by the Coriolis effect.

On a spinning planet, whenever you
have a current,

you get these beautiful swirls formed.

I think we've got some eddies over
here.

So, if we have a look, and I think
Eleanor can see this as well.

So, we've got a map here that shows
surface currents.

So, Eleanor, we can see these eddies.

Tell us what we can see here.

- Off the tip of South Africa, there,
you can see these ocean currents

as the really highlighted strong rings
or doughnut shapes, really,

of the currents.

These are several hundred kilometres
across in the real ocean,

and they're carrying warm and salty
water from the Indian Ocean

over long distances and into the
Atlantic.

- And these aren't just... So, we can
see some really obvious ones here,

but these - these are all over the
ocean, aren't they?

- That's right, that's right.

So, these are some of the largest,
most spectacular ones down there,

but really, these eddies are
everywhere.

- And why do you study these things?

Why are oceanographers interested in
these eddies?

- So, eddies carry heat and properties
around the ocean.

They also contain a massive amount of
kinetic energy -

something like 80% of the total
kinetic energy of the oceans.

- So, these are these enormous
features.

And there's a connection between this
ocean weather

and the climate, isn't there? Tell us
a little bit about that.

- Absolutely. So, what we're starting
to find out now

is that where these eddies deposit
their energy,

where they eventually dissipate and so
you can no longer see them,

has an influence on shaping the
large-scale ocean circulation.

So, the currents that are moving and
influence...

Influencing how the ocean influences
climate.

- Brilliant. Thank you very much.

Well, good luck on your research
expedition,

because I'm sure that's going to be
really exciting.

And thank you for joining us.
- Thank you.

- APPLAUSE

So, there is ocean weather.

It's slow - slower than our atmosphere
-

but it's making these amazing patterns
all the time.

So, the patterns are all very pretty,
but do they matter?

You know, it's always nice when things
are pretty.

Well, to see why they matter, we've
got a demonstration here,

and the important part of this
demonstration...

Oops!

THEY LAUGH

Thank you, Fran.

..is the cannonball here.

So, I'm just... It looks just like a
normal cannonball.

I'm just going to flick some water at
it

and you can see the water... Woo! ..is
evaporating off it.

And that's because this cannonball is
really, really hot.

It's around 350 degrees Celsius.

So, it's definitely not something you
should touch.

And it's carrying a lot of energy,
about 300 kilojoules.

So, what Fran is going to do, while I
stand back...

..is she's going to put the cannonball
in the water

and I'm going to follow along with
this thermal camera.

We can see on the thermal camera the
cannonball is super-warm

and here we go into the cool water.

LOUD HISS

That is a lot of hissing!

So, we basically just dumped all of
that energy into the water here.

Now I'm going to do something that
looks like a terrible idea,

which is put my hand into the water

and it's not actually that hot.

What I'm going to do is mix it up, and
you can see with the camera

there's cooler water coming through
from underneath.

But actually, considering the
cannonball was at 350 degrees C,

what we could see with the camera is
that the water over here is only

around 40 degrees C, so we dumped all
of that energy into the water

and the water's only heated up by
about 15 degrees -

really not very much at all.

And what that demonstrates is
something that we call

the heat capacity of water,

and this is really important - that it
takes an enormous

amount of energy to heat water up by
even a tiny bit.

And this is why something like boiling
your kettle

is such an energy-intensive thing,

because you have to just keep pouring
energy in.

But the critical thing here is that
even though the water hasn't

heated up by very much, the energy is
still in there.

This water is now a store of heat
energy,

and that matters when it comes to the
ocean,

because the ocean can also store
energy.

So, let's have a look to see why that
matters for Earth.

Let's have a look at a planet which
doesn't have an ocean.

Let's have a look at Mars.

We know it as the Red Planet and it's
got very little water,

no known liquid water.

And the thing about Mars is that there
are these

enormous temperature variations.

As the planet rotates around and parts
of it go from day to night

and back again, the daily variation in
temperature

can be 100 degrees centigrade - it's
enormous.

Just imagine how uncomfortable

living on a planet like that would be.

So, let's come back to the Earth

and have a look at why that doesn't
happen on Earth.

So, the way that things work on Earth
is that energy flows

through the Earth's system.

It comes in as sunlight, it hangs
around in the Earth a bit,

and eventually it's lost to space.

So, what happens is that the ocean,
when sunlight hits it, warms up,

so it stores energy.

It's acting like the battery of Earth.

It's recharged with energy whenever
there's loads of sunlight,

and then on the cooler days,

it can release that energy back into
the Earth's system.

So, it's basically the storehouse of
energy on Earth.

And that means that you don't get
these extremes of temperature

on Earth in the same way that you do
on Mars, because when it cools down

a little bit, the ocean gives you some
energy back

and then it recharges itself when the
Sun comes out again.

And so the temperature on Earth
doesn't vary very much.

The other thing about those patterns
that we saw

is that they're showing us not just
that the ocean is storing energy,

but the temperature is telling us
where it's stored,

and overall, the ocean is moving
energy from the Equator

towards the poles.

It's spreading it out, sharing it out,
around the planet.

So, when we asked the question about
why we've got such a nice,

stable planet to live on, why it's so
easy to live here -

it's because we've got an ocean.

It really matters that we've got an
ocean.

So, we've had a quick tour through the
physical nature

of the ocean, and it's varied and
dynamic.

It's got all these beautiful patterns

and it carries vast amounts of energy.

But there are more things in the ocean
than heat.

So, virtual audience, what are your
ideas for what other things

you might find in the ocean?

Shout things out.

Oh, yes, just shout.

ALL SHOUT AT ONCE

- Fish!
- Sealife!

- SHOUTING CONTINUES

Coral reefs!

Seahorses, yes.

OK, so we have lots of ideas there.

Seahorses and turtles and fish

and the thing that they've all got in
common

is that they are all alive.

Our ocean - this physical engine - is
full of life

and we can see a little bit of that
here.

So, what we've got here is a tiny drop
of ocean water

from Gylly Beach in Cornwall here.

And we've got a green laser that's
shining through the droplet

and it's projecting the insides of the
droplet onto the screen here.

And we can see that there are these
little things moving around

inside - tiny, tiny things - and we
could never see them

inside that droplet with our own eyes.

But the laser is showing us there is
something there.

There is life in this ocean water.

So, the ocean isn't empty.

It does have living things in it.

But to see the little ones, you need
to know how to look.

And so I have a guest who can help,

so please welcome Professor Bridget
Wade.

APPLAUSE

Thank you for joining us, Bridget.

Now, we're going to talk about
something called phytoplankton.

Tell us what those are.

- Yes, so, phytoplankton are these
microscopic, single-celled organisms

and they photosynthesise in the
oceans.

And we're used to thinking of these
larger organisms like whales

and turtles and things,

but phytoplankton actually make up
about 90% of the ocean's biomass.

- So, they're really tiny and they're
harvesting sunlight.

- Yes. So, they're photosynthesising
and therefore taking in oxygen

and actually in the air that we
breathe,

about 50% of the oxygen comes from
phytoplankton.

- So, we really need them there, in
the oceans.
- Yes, exactly.

- You've got some examples here.
- Mm-hm.
- Let's have a look.

- Yes. So, here I have the
coccosphere.

It makes these plates out of calcium
carbonate,

and the White Cliffs of Dover that
people will be familiar with

are made out of these.

- And it's really intricate.

It's just a single cell and it's so
delicate.
- Yeah.

And there's millions of species, and
they're all very different

and diverse and beautiful.

- And you've got another there one as
well.
- Yes.

This is a diatom and these are made of
silica.

And just like all the other types of
phytoplankton, they're living

in the surface waters of the ocean and
photosynthesising.

- And how big... Because, you know,
I've never walked out onto a beach

and seen one of those, so how big are
they?

- So, they're very small.

Everything's less than half a
millimetre in size.

So, less than the size of a grain of
sand.

This would be about 100 microns

and this one would be about ten
microns.

And there's a thousand microns in a
millimetre.

- So, let's play an imagination game
here.

Audience, we're going to imagine that
we're shrinking ourselves down

so that the entire lecture theatre is
the size of that drop.

And we're going to populate that with
some phytoplankton.

But that's quite a lot of
phytoplankton,

so we needed some help.

And Hornsey School for Girls helped us
out by making models.

So, here we are.

So, Bridget, can you recognise
anything they're making here?

- Oh, yes.
- Looks like a lot of work!
- Some of them are amazing.

And they're all single-celled
organisms, but they're beautiful.

They all make these amazing shells

and they're really diverse and ornate.

- I like the amount of creativity
going on here.

It's like everything in the craft box
is being used.

All of that detail, and yet the
phytoplankton

just make it for themselves.

We've got some of the examples here,
and these are to scale.

Imagine that drop was the size of the
lecture theatre

and these are the right size.

So, what have we got here, Bridget?
What can we see?

- So, these are some of the
coccolithophores

that are made out of calcium
carbonate.

We also have a diatom here.

They're very important
photosynthesisers.

They make about 25% of our oxygen.

- And then we've got descending on us
here!

THEY LAUGH

What are these ones?

- So, these are dinoflagellates, and
they kind of look like spaceships

and Christmas decorations, and they're
very ornate

and they have these amazing flagella.

- So, these are the things that are
hanging off the bottom here?
- Yes.

- And are they using them? What do
they do?

Do they swim with them? What do they
do with those?
- Yes.

They can use them to sort of move
through the water.

But these are really... They're
plankton - they're floating.

They're not really swimmers. They're
just drifting. Yes.

- Do these features have functions?

Why do they need to look so different?

- Yeah. So, just like plants, they
need nutrients from the ocean

and they need oxygen and sunlight,

and so trying to increase their
surface area,

and they also might be trying to
prevent predation.

Everything feeds on these, so they're
the base of the food chain.

So, all marine life is dependent on
the phytoplankton.

You have this invisible forest of
unicellular or single-celled

organisms, and they're really
important.

I mean, some of the ones here, these
are cyanobacteria.

So, they're bacteria and they
photosynthesise

and they're actually the most abundant
photosynthetic

organisms on Earth.

- So, they're all just hidden in the
oceans

and different ones are found in
different places as well.
- Yes.

And they're all so stunning and
beautiful.

And they're living in the surface
waters -

they want to be in the sunlight.

But you find them everywhere from the
Arctic

to the tropical regions.
- And they're keeping everything...

I love the idea that you could swim
through a forest of the ocean

and never know it was there...
- Yes.
- ..because it's so tiny.

- And I feel so lucky that I get to
see these.

This microscopic world!
- You get to admire their beauty.

Brilliant. Thank you very much,
Bridget.
- Thank you.

- APPLAUSE

So, phytoplankton are great sun
harvesters, they're great at taking

the energy from sunlight and using it
to build sugars

and to build themselves, but if you
can't harvest sunlight

for yourself, then a phytoplankton
looks a lot like lunch.

And it's time to meet the zooplankton
- they're tiny creatures

that also drift on the ocean currents.

And some of them are big enough to
see,

like the jellyfish we saw at the
start.

But lots of them are really tiny
little animals.

But if you walk out, if you go to the
beach one day,

you look in... you're wading in the
ocean,

you often won't see zooplankton.

You can see lots of other things,

but there aren't any little tiny
animals to look at.

So where are they?

If there are all these zooplankton,
where are they living?

Well, last year I did a really special
scuba dive.

I was out near Hawaii, so I was in the
middle of the Pacific Ocean

and we got into the water just as it
got dark.

So we were floating in the boat a
couple of kilometres offshore.

The ocean floor was two kilometres
beneath us,

so it was really, really deep and the
water was deep navy blue.

And so we got over the side of the
boat and we floated

and the sun went down.

And the ocean went black.

We floated in the middle of the
Pacific and then all of this

rose into the water around us and it
was astonishing.

So what we can see here are just so
many little creatures.

We can see their sort of jelly-like
bodies.

Some of them are single by themselves.

Some of them are attached together.

This one was making little streaks of
light.

So some of them were bioluminescing

and some of them are big enough

to see on this image here.

But there were loads and loads that
were even smaller than that,

and we were just surrounded by them.

I could have spent hours watching all
of this.

So where had they been?

Well, they'd been hiding down in the
depths.

So, zooplankton like this feed on
phytoplankton.

The phytoplankton need to be up near
the sunlight, but the zooplankton

don't want to be eaten by fish.

So they hide deep down in the depths.

And when it gets dark, they rise up
towards the surface.

So, like this, where they can hunt at
night and they can hunt

without being seen.

And then when the sun comes up the
next morning,

they sink down back into the depths.

It's the biggest migration on Earth.

It's an astonishing phenomenon.

But life in the ocean isn't easy and
to show you

some of the challenges we've enlisted
the help

of the Lilian Baylis Technology School
to play a game.

So here's the game. We need to explain
the set-up to start with,

so we've got three zones.

So, in the middle here, we've got the
ocean.

That's the bit in between those two
lines.

Down here, this is the bottom of the
sea.

And then up above the ocean up here
where the sunshine is,

that's the atmosphere,

so that's outside the ocean.

And then we've got different types of
players.

So we start off with the players in
blue.

So the ones with the blue hats,

these ones are the zooplankton.

And it's their job

to scoot around the ocean.

They're these tiny animals and it's
their job

to collect nutrients.

So nutrient balls like this one,

because that's what you need

to build life out of.

So we've got some nutrients, but the
zooplankton have another job,

which is to avoid the fish.

And if they get caught by a fish,

then they and any nutrients

that they're carrying sink to the
bottom of the ocean

and they can't carry on with the game.

So let's start off with a countdown.

So are you ready for a countdown from
three?

Ready.

ALL:
- Three, two, one, go!

- So we can see... here go the
zooplankton,

they're collecting the green at the
top.

Fish are going round collecting
zooplankton.

And you can see that when the fish
have touched the zooplankton,

the zooplankton sink down here and
they carry nutrients

down into the depths with them.

But after a while, it starts to look
quite boring, doesn't it?

Because what's happened is that all
the nutrients

are down here at the bottom and
there's nothing left in the ocean.

There's no nutrients near the
sunlight, so nothing can grow.

So this doesn't work very well,

but we can try the game again

with another player.

So our new player is dressed in red
here.

She's got a cape and a hat and she has
a very special role.

What she can do is she can go down to
the bottom of the ocean

and she can collect nutrients

and she can bring them up to the
surface.

So let's play the game again. Off they
go.

So here go the zooplankton.

They're collecting up the nutrients.

The fish are touching the zooplankton.

So we're getting nutrients to the
bottom here.

But then our red player can come
along.

She's collecting up the nutrients, so
they go back to the top

of the ocean and then the zooplankton
can go again

so the life can carry on.

So here we go.

More nutrients being collected down
here.

And she's going to take them all the
way round and put them back

at the top of the ocean.

We can see that once you've got this
extra player that does this job,

then the game of life can just go on
and on.

So the question is, who was this
player?

So virtual audience here, would you
like to guess who that player was?

What's in the ocean that might do that
job?

Let's shout out some guesses.

ALL SHOUT AT ONCE

Some type of plankton?

- Plankton?

- Different fish?

- Different fish? Different fish might
do that job.

There's lots of ideas here.

Well, let's have a look.

So what our caped crusader really was
-

her job is that she was a whale and
what she was doing was eating

at the bottom and then coming up to
the top

and then she was pooing.

And this turns out to be really
important.

So I've got a picture of some whale
poo up here.

And it's...it's a bit icky, isn't it?

It's red. It's floating in the ocean
there.

And turns out it's really hard to get
a sample of real whale poo

because whales are quite shy about
this kind of thing

and it's quite hard to collect it.

So I can't show you real whale poo.

What I can show you is a model to talk
about what it does.

So here's the model

and let's put the poo in the ocean.

It's... Eugh!

It's horrid!

So we can see that as soon as it's in
the ocean,

it starts releasing things.

And the reason that the whale poo is
red

is because it's full of iron

and that's a really important
nutrient.

And they also have other things

in them, like nitrogen.

And so basically whale poo

like this, little pieces of poo,

or sometimes it's a bit more liquid.

It's all really icky.

And they are incredibly concentrated
doses of ocean fertiliser.

And because whales do deal with

all their bodily functions,

apart from feeding at the surface,

what they do is they eat things

like krill down in the depths

and then they come up to the surface

and they release their poo

and just look, they're releasing

these nutrients everywhere.

They're fertilising the surface ocean.

So the lesson is that life in the
ocean has a problem.

The sunlight is at the top

and, over time, the nutrients tend to
sink downwards.

But life can solve that problem.

Something is doing this very special
job of bringing the nutrients

back up to the surface

so the game of life can carry on.

It doesn't have to be a whale.

So what is there that can break this
barrier, that can bring

the nutrients from the depths up to
the sunlight?

Well, it turns out that on a rotating
planet,

Earth itself actually helps us.

And whenever we have a current on a
rotating planet,

there's something counterintuitive
which happens,

which is that the currents

can't go in a straight line.

They have to curve.

The nutrients are pulled upwards to
the surface.

So what's actually happened is that

the surface is being pulled away and

it's leaving a gap in the middle.

And so the water from underneath,

with all those nutrients,

can rise up through that gap.

And this is called upwelling

and it's really important

in the ocean.

This doesn't happen everywhere,

if we have a look at the globe here.

And what we're looking at is a map of
chlorophyll.

And this chlorophyll shows us that
life is growing.

So it only happens in places where
there's both nutrients and light.

And if we look around here,

we can see that there isn't
chlorophyll everywhere.

There are patterns,

but there are some places where it's
really strong.

So if we look at the side of South
America here,

all down here, look at this,

there's loads of chlorophyll down this
coast.

And the reason is that this is a big
region of upwelling.

There's nutrients coming from the deep
ocean

coming to the surface, meeting the
sunlight, and it makes

this region a city of the ocean.

There is so much life there.

But if we move the globe round a
little bit further,

here we get to the middle of the North
Pacific here.

We can see there's a huge region here

where there's almost nothing growing
at all.

And that's because there is no
upwelling here.

Actually, things tend to go the other
way.

And so what we're seeing is the
structure of the life -

there are these cities of the ocean
along the coasts here

and there are deserts

where the nutrients can't get up to
meet the sunlight.

So what we've learned here is that
there is constant recycling.

There are only so many atoms on Earth.

Basically, if you want to succeed as
life,

what you need is to make yourself from
poo

because that's how you recycle the
atoms

that were something else before you.

The ocean is a massive recycling
system

and we're basically all made from poo

because that's how a healthy ecosystem
works.

And now we can start to think about us
humans and our relationship

with our ocean.

We look up here, up at the Pacific
Ocean,

I could look at this view for hours.

Now, our European maps are dominated
by land

cos that's where we live.

We make our maps that show the places
where we live.

But in the Pacific here, there are
lots of tiny islands.

And the people who live here,

their worldview isn't dominated by
land.

It's dominated by the ocean.

I mean, why wouldn't it be?

You've got all this ocean and the
people on those islands

have centuries of understanding the
ocean, of observing it

and of learning how to navigate across
it.

So to share their knowledge and
perspective,

I'm really honoured

to be joined by one of the greatest
modern Polynesian navigators,

from Hawaii, Nainoa Thompson.

Nainoa, hello.

Could you perhaps start by telling us
a little bit about the place

where you live?

- I'm in, like, the largest country on
the Earth called Polynesia.

It's mostly ocean - it's 600 times
more water than land.

And so I come from an ocean world.

- Now, most of our audience won't be
familiar with the story

of this amazing voyaging canoe -
Hokule'a.

Could you give us an overview?

- There was an amazing group of
dreamers and pioneers,

courageously said, "We're going to
bring back our culture.

"We're going to bring back our tie to
the oceans

"by building the single most important
artefact

"of Polynesian culture, the voyaging
canoe."

These are big canoes, sailing great
distances.

From the indigenous native
perspective,

the navigation integrates everything
from the ocean world,

whether it's the heavens, the stars,
the sun, the moon, the planets,

to wind, to clouds, to the quality of
light at sunrise and sunset,

sea birds, sea life in the oceans,
reading the ocean waves.

I mean, if the basis of modern science
is observation,

and these are great scientists -

I would like to put them amongst the
best.

- It feels like we're at a critical
point here where we risk losing

something really important if we let
our climate

and our oceans suffer any more.

What is your advice?

What do you think we should do about
it?

- When we industrialised to build
better lives for us as humanity,

it worked.

It changed everything.

But what we didn't know was its impact
on climate.

And we didn't know its impact on
ecology

and we didn't know its impact on
culture.

But today we know.

This lecture is focused on 11- to
16-year-olds.

They are the most important generation
in human history ever.

They are going to be given the tools
to do what we could not do

in the past, the power of technology,
their imagination,

their courage, their ability to access
information

and make good decisions.

It's about the choices.

Take 500 choices that we make every
day, times it by eight billion,

that's four trillion human choices per
day.

This next young generation is going to
say, "Let's change those choices.

"Let's make them good choices."

That's going to change the world.
- Thank you very much, Nainoa.

It's been a pleasure to talk to you.
Thank you.

So let's have a look at what humans
are doing to the ocean

and how that affects our climate.

Now, we've got we've got the Earth
system here.

We've got the sun up there.

And the sun is going to deliver energy
to the Earth system,

which is down here, so off we go.

So here comes the energy.

It flows into the Earth system, but it
doesn't just pile up and pile up.

After a while, it will start flowing
out.

Now, on Earth, that means the energy
is radiated away into space.

But here, it means that the energy is
going to come out of this tube

and it's going to start falling into
this bucket.

So we've got energy coming in and
we've got energy flowing out.

And as long as the energy flowing in

is the same as the energy flowing out,

then the amount of energy in our
system here stays the same.

And we can see how much energy there
is

because there's a dial here so we can
make a mark there.

So that's how much energy is in our
system at the moment.

Now, we learned in the first lecture
from Chris that carbon dioxide,

all that extra carbon dioxide we're
putting into the atmosphere,

that's a greenhouse gas,

and what it's doing is blocking the
flow of energy into space.

It's slowing it down.

So I'm going to do that here by
slowing down -

actually, I'll do it at the bottom -

slowing down the flow here

and not spilling all over the floor.

And what we can see

is that the dial...

Can you see it's creeping up?

Because energy is building up.

So we've moved from where we were

all the way around.

We can see energy is accumulating in
the system.

And this is what climate change is.

Carbon dioxide is slowing the flow
out.

Energy is slowly building up in the
Earth system

and it's changing how the Earth energy
works.

So we've got a lot of extra energy
here.

The question is, where is it going?

And we do know.

93% of the extra energy that we're
accumulating

in the Earth system because of climate
change,

93% of it ends up in the ocean,

and if it wasn't, the Earth would be
far, far warmer than it is now.

So that is a lot of energy and it must
come with some consequences.

So remember that the ocean doesn't
just store up that energy -

it can also release it back into the
Earth system

and that's having major consequences
at the poles.

And this is water being added to the
ocean from land.

So it was locked up as ice on land.

It melts and it flows into the ocean

and that's causing problems.

It's causing sea level rise.

But that is not the only problem.

Let me show you something else over
here.

So I've got to put my glasses on for
safety.

So what we've got here...

WHOOSHING

..is a little flask of ocean here,

and I'm just going

to heat it up from underneath

and while that's heating,

we've got a lovely cartoon

in the background here

that shows the ocean.

We've got the beach, we've got some
land

and we've got someone's house at the
top.

And we can see the blue level here -
that represents the sea level.

And you can see that as I heat up the
flask, sea level is rising.

So what's happening is that I'm not
doing anything to this water

except heating it up and warm water
just takes up more space.

So what's happening is it's pushing
out of the flask

and it's pushing up and it's creeping
up the beach here,

and this also happens in the ocean.

As we add extra heat energy to the
ocean,

the warmer water just takes up more
space,

and so sea level rise is also...

We know that current sea level rise

is just over three millimetres per
year

and about 40 to 50% of that

is just caused by the thermal
expansion of sea water.

ALARM BLARES

So as well as all the extra water
we're putting into the ocean,

the extra heat is causing additional
sea level rise all by itself

because the water we've got is just
taking up more space.

But the ocean energy carries on into
the Earth system,

it then heats up the atmosphere and
the warmer the water is,

the more energy the ocean can deliver
to the atmosphere.

THUNDER CRASHES

Some lovely weather here.

So weather's really complicated and it
does take really careful science

to understand the influence of
individual factors,

but there's a general consensus that
warmer sea surface temperatures

will make storms with strong winds

and more intense rainfall occur more
often.

So, for example, in 2018, Hurricane
Florence made landfall

on the east coast of the US

and scientists estimated, in one of
the first studies of this type,

that the rainfall intensity in this
storm was higher by 5%,

just because of the effects of climate
change.

So, we've followed the energy in the
ocean and now

we're going to come to the role of the
ocean in carrying stuff,

in carrying atoms that aren't water.

And we've seen that the energy
accumulation in our Earth system

is due to carbon dioxide.

We often hear about carbon -

there's carbon budgets

and zero-carbon things.

People talk about carbon-free
activities.

So what about the carbon in the ocean?

Well, the oceans are doing as an
enormous favour

because they're taking up carbon
dioxide.

And since the beginning of the
Industrial Revolution,

they've taken up an amount equivalent
to all the oil

we have ever burned -

a staggering amount of carbon.

Just in the hour duration of this
lecture,

one million tonnes of human generated
carbon dioxide

will have been taken up by the ocean.

But how does it get there?

It's all very well to say it goes in,
but how does it go in?

Well, this is my area of research.

I study bubbles in the ocean.

So these are packets of air surrounded
by water.

And you might think of bubbles as
being nice, gentle things

that come along in fizzy drinks or in
the bath.

But let me show you the bubbles that I
study.

So this is footage that was taken from
the back of a ship

in the middle of the North Atlantic.

The average height of the waves here
is ten metres.

This was a big storm.

And this is a view that has been seen
by seafarers for centuries.

But they couldn't see the bit that I'm
interested in,

which is just the top few metres just
underneath the surface.

So let's take a calmer example here.

We're looking up at the sea surface

and we're about to see a little wave
break over the top

so we can see what's happening
underneath.

So it's going to come in from the
right. Here we go.

There's the breaker.

And you can see we've got this plume
of bubbles formed

just underneath the surface.

And some of them go straight back up
to the surface

and other ones stay down, hang around
in the water column.

And these are really important

because they're helping the ocean
breathe.

That's why we go out in these fairly
vile conditions, really,

these big storms, to find out how many
bubbles there are,

where they go and what they're doing.

And the reason for doing this is to
study the ocean breathing

and find out whether that's going to
change in the future.

So what difference would the bubbles
make to the breathing?

Well, we've got a demonstration over
here to show you.

So we've got some sea water that's
been coloured down the bottom here

and Fran's going to pour in some
carbon dioxide.

And what we're going to see is that...

So carbon dioxide is an invisible gas,

but what we'll see is that as it fills
up,

it's already put that one out,

it's put both candles out,

so we're going to fill up

the headspace here

with carbon dioxide.

And we've got some dye in the water

down here that's going to track

where the carbon dioxide is going.

So now we've dealt with the gas,

we're going to start the breaking
wave.

So we've got a little tipping bucket
here

that's going to make little plumes of
bubbles

in the tank, just like the breaking
waves in the ocean.

So we get loads of bubbles, we get a
lot of turbulence.

What you can see is that the water is
changing colour

and the reason it's changing colour

is that it's taking up the carbon
dioxide in the headspace.

It would have dissolved.

It might dissolved very slowly
otherwise,

but when you've got the bubbles and
you've got turbulence,

all those little packets of the
atmosphere

pushed down into the ocean,

they are transferring the carbon
dioxide much more quickly,

so the breaking waves and bubbles,

and big storms like the one you saw at
the start,

basically are speeding up

the process of ocean breathing.

They're speeding up carbon dioxide
being taken into the ocean.

And this is what's happening in a big
storm.

So my work is to look at this kind of
thing and predict

how it's going to change in the
future.

But what I didn't tell you is what the
dye in the water here is.

You can see it changed colour, but the
reason it changed colour

is that what it actually is, it's an
indicator.

It's telling the pH of the water - how
acid or alkaline it is.

And the water here started off at
about the same pH

as the ocean in 1800, so around 8.2.

And you can see, as we added carbon
dioxide,

what happened is we change the pH,

we made it less alkaline and more
acidic.

And although this is an extreme
example,

that process is also happening in the
ocean.

As the ocean takes up all this extra
carbon dioxide,

this is ocean acidification.

It's making the ocean less alkaline,
so we've changed...

The extra carbon dioxide has already
changed the pH -

how acid and alkaline the ocean is,

it's changed that across the whole of
the surface ocean,

and that really matters for life.

So we saw... I've got some samples
back here.

We saw with the phytoplankton at the
start

that lots of them have shells made of
calcium.

And for them to build those shells,
they need an alkaline environment.

And when you add more carbon dioxide,
it takes more energy

to build those shells.

So these shells like this are made out
of calcium carbonate.

And we know, for example, that corals
are really sensitive

to ocean acidification

and barnacles and mussels also don't
do very well in ocean water

that's got more carbon dioxide
dissolved in it

and it affects the chemistry of other
processes.

So, overall, it's a complex story,

but what we do know is that when we
change the pH like this,

firstly, we're doing it too quickly
for evolution to catch up.

The animals and other organisms
haven't got time

to evolve, to adapt,

so there are new winners and new
losers.

And overall, it seems that the future
ocean, the ecosystems,

are going to look different

because there's going to be less
biodiversity,

just because of this ocean
acidification.

So although it sounds great that the
ocean is taking up this carbon,

it's taking it away from the
atmosphere,

potentially, it has really serious
consequences for ocean ecosystems,

which is all... It's a bit gloomy.
It's a bit sad.

So it is time to get back to the
subject of poo

to cheer everyone up.

And we've seen that carbon can cross
the ocean surface

in big ocean storms.

Where does it go next?

So to answer that question, please
welcome Dr Stephanie Henson.

APPLAUSE

Hello.
- Hello.

- So tell us, first of all, what parts
of the oceans you study.

- So I work on the twilight zone -

that's the part of the ocean where no
light penetrates.

It's down to about a thousand metres
depth.
- And you've got some samples

of what you find there. What have you
got to show us?

- So what I've got here is actually
some plankton poo.

So this has been produced by a
zooplankton -

those little critters that you met
earlier.

OK, here we go poo hunting -

keep your fingers crossed, everybody,
that we find some.

- Oh, we've got a piece there.
- It's tricky. Here we go.

Get it into focus. So it's this orange
thing

with all this fluffy stuff.
- This orange thing.

- Exactly. All that fluffy stuff
around it. Oh, da-na! There we go.

- The picture we had before was

that we've got the phytoplankton which
are harvesting the sunlight,

the zooplankton eating the
phytoplankton.

So how does this... explain how the
cycle carries on.

- Yeah. So zooplankton are tiny little
animals

and like every animal, once they've
eaten, they've got to poo.

And this is an example of what their
poos look like.

But the important thing is their poo's
full of carbon

and it sinks down deep into the ocean.

- So there's carbon cycling in the
ocean, that's the big picture here,

isn't it, that carbon is going round
around, but some of it via this poo

kind of drops out of the bottom of
that system?

Yeah, that's right.

- Actually, only about 1% of the poos
make it down into the deep ocean.

It doesn't sound like much, but it's
super-important

because without the poos, atmospheric
carbon dioxide levels

would be about 50% higher than they
already are.

- So how do you go about collecting
this?

- Well, one of the ways that we do
that

is with what's called a sediment trap,
and we have one here.

It's basically a giant funnel, as you
can see.

And we put it down near to the bottom
of the ocean,

several thousand metres deep.

At the bottom, there's a bunch of
bottles.

We open those on rotation for about
two to three weeks at a time.

And it's out there for a whole year.

And the ship comes back, it pops to
the surface and we pick it up.

- Now, here at the Royal Institution,

we are definitely not shy of playing
with the toys.

So we do have some marine snow we're
going to release from above.

Oh, here it all comes.

So that's quite a lot, isn't it?

- Oh, wow.
- That's quite a lot!

So how does this work in the ocean?

Does it come down in big kind of
rainfalls like this?

- Well, it's not quite like that.

So it's not a massive snowfall, like
we've just had there with confetti.

It's more like a gentle drizzle of
marine snow and plankton poo

falling to the bottom.

Only a tiny fraction of the poo that's
generated

makes it all the way to the deep
ocean.

- But this is having really big
consequences for climate change,

because if it comes out of the
atmosphere into the ocean

and then from the ocean it goes down
into the deep ocean,

then it just stays there.

- That's why it's so...

Only about, like I say, about 1% makes
it down right to the deep,

but once it's there, it's stored there
for hundreds, thousands

of years, even millennia, if it makes
it to the sediment.

So it's super-important for regulating
our climate.

- So zooplankton poo like this is not
just something...

It's no laughing matter.
- Yeah, absolutely.

- That is brilliant. Thank you very
much, Stephanie.
- Thank you.

- APPLAUSE

So we've only just touched on the two
big things

that the ocean moves around - heat
energy and carbon,

but it's enough to see

why lots of the things that humans do
is causing problems.

We know, for example, that the reason
plastics

are a problem is they don't fit in
with the ocean's recycling system.

Nature doesn't have a way to help them
turn into something else,

so those atoms are kind of stuck.

We know that overfishing affects
ecosystems, so it shifts the balance

of what's recycling round and what's
living where.

And we know that the polar regions,
which are a critical part

of the ocean engine, are changing
really quickly, and that's affecting

the rest of the engine.

So we have lots of problems to deal
with,

but we also have lots of knowledge.

And I am really excited about being a
citizen

of an ocean planet.

It's such a fantastic thing to be and
there's so much to appreciate.

So when you look out over the ocean,

just imagine what's going on down
there - the swirling ocean weather,

the shunting of vast amounts of heat
around the globe.

Imagine the zooplankton rising and
falling as the planet turns.

And imagine this blue engine shifting
the nutrients

that are necessary for life.

We may live up there, but if we want
to get life right,

we need to work with what's down here.

We're part of this ocean planet, not
separate to it.

In the next lecture,

Tara will take you even further up
into the atmosphere

and look at how humans can live
sustainably on Planet Earth.

APPLAUSE