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All life on Earth began
in the oceans.

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But now they're changing
more quickly

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than ever before in human history.

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And we are responsible.

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In a television first, we're going
to attempt an ocean autopsy,

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a comprehensive health check of the
North Sea from top to bottom.

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This is a place where physics
and chemistry and life are all woven

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together, and it's directly
connected to each one of us.

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We have to understand our actions
here because the clock is ticking.

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Whatever's happening in this sea
will give us a strong indication

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of where our global ocean
is heading.

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I'm physicist and oceanographer
Dr Helen Czerski,

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and I'm joining
a state-of-the-art research ship.

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It's back on board, so it's
all right.

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We're happy! Now we've just got
to see what data's on it.

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The experiments we carry out
on board will transform our

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understanding of what we're doing
to these waters.

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That was quite a dramatic reaction.

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I'm zoologist Dr George McGavin.

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I'll be investigating how what we
do on land impacts life at sea.

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Oh, my goodness!

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Absolutely loads of parasites.

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Our investigation will tackle some
of the biggest and most challenging

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issues facing our planet today.

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What happens to the eight million
tonnes of plastic

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we dump into the ocean each year?

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99% of this plastic has been,
well, lost at sea.

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What effect does chemical pollution
have on marine life and on us?

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I'm just having this image
in my head

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of somebody tipping 220 tablets
an hour into the Thames,

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day after day.

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Can life in the oceans
survive as the planet warms?

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So the more methane comes,
thus the warmer it gets.

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The latest science is also
bringing hope.

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I'll discover innovative
ways to combat rising seas.

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These marshes will be able
to keep up

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with levels of sea level rise.

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It just goes to show what you can
do when you work with nature,

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and not against it.

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From land, from sea,
even from outer space,

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we're performing a definitive
health check on our oceans.

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To discover how they're faring today

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and how to preserve them
for the future.

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Our investigation begins
at the Dutch harbour of Texel.

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I'm about to set sail
on a pioneering journey

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aboard the Pelagia, one of the
best-equipped science laboratories

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at work on the sea.

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So this is my home for the
next two weeks,

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and, if you want to study the ocean,
you really need access to this

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kind of cutting edge facility
to get into it.

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And I am so excited about going
back to sea. Can't wait.

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I'm sailing with a multinational
team of oceanographers

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and marine biologists.

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We'll work, sleep and breathe
ocean science.

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We'll gather important
data on two of the key factors

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transforming our seas today -
pollution and climate change.

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Our investigation takes place
in the North Sea, sandwiched

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between Great Britain and
north-west Europe.

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We'll sail over 750 nautical
miles and visit 16 locations.

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Industry has polluted these waters

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for longer than any other sea
on the planet,

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and, in the past 50 years,
the North Sea has warmed twice

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as fast as the rest of the
Earth's oceans.

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So it's a bellwether for where
they might be headed.

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It takes a day to reach
the first location.

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30 miles off the Dutch coast,

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we begin the first of our
major investigations.

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An experiment that could uncover
shocking new depths to one

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of the biggest crises
facing our oceans today.

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We've all seen the pictures
of plastic debris

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floating in the world's seas,
and how it's killing marine life.

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But the Pelagia's chief scientist,
Professor Helge Niemann, believes

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this is just the tip of the iceberg.

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Helge's colleagues have recently
worked out that there

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could be a quarter of a million
tonnes of plastic

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floating on the surface
of the world's ocean.

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But that accounts for just
a tiny fraction

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of the plastic we've thrown
into our seas.

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At most, a few percent
of all the plastic

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that we have been dumping
in the sea,

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we know where it is,
and the vast majority of this

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plastic has been, well, lost at sea.

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And the question is,
where did it go to?

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Hold it, hold it, hold it...
and let go.

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The sampling Helge and his team
are conducting here in the North Sea

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is part of a worldwide search
for the 99% of ocean plastic

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that's gone missing.

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He's using specially designed
fishing nets.

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We use this net to fish plastic

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that is floating at the surface
of the ocean.

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Skimming the surface of the ocean

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and collecting everything in one
place. Exactly, exactly.

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When we take the net out of
the water to inspect our trawl,

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at first sight I can't see
any plastic...

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Lots of goo!

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..but it is here. It's just
fractured into tiny fragments.

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This white thing here,
that's a piece of plastic.

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There's a smaller one.

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There's two pieces.

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And is that normal? Is that what
you expect for this sort of ocean?

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Unfortunately, yes.

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A look under the microscope shows
the tiny fragments of plastic

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in extraordinary detail.

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These little white specks,
it's pieces of plastics.

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What you can see, it already
has a rough surface,

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it is already starting to
fall apart.

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You can see it's really smashed up,
that it's been bashed around.

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Yeah, it's been bashed around.

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Exposed to sunlight, saltwater,
wind and waves,

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plastics become brittle.

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You can see in this irregular
surface how, actually, microplastics

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are being formed because the very
top part here will break off

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and then you have an ever-tinier
piece of plastic that is coming

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out of this. If it had been left
in the ocean, it could have

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broken again and broken again.

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Just one plastic bag in the ocean
can disintegrate into over a million

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of these microplastic pieces,

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which then sink
below the ocean surface.

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So what have we got on the
screen here?

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So this is a tiny piece
of microplastic.

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Very high magnification on this,

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and we see a planktonic creature.

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Sometimes, you see like a
small, entire ecosystem

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that is living on this.

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Microscopic creatures and plants
called plankton

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form the foundation of the
ocean's entire food chain.

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And here in Helge's samples,
they're living side-by-side

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with green flecks of microplastic.

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Other scientists have recently
discovered

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something even more sinister.

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Zooplankton organisms can also
ingest microplastics

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if they're small enough.

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So these are the tiny animals
that hang about in the water.

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Exactly. Very, very little ones.

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So this is the base of the food web
in the marine ecosystem.

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So they have been seen to eat
plastics directly? Yes, precisely.

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It sounds as though these things

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are finding their way up the
food chain.

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Yeah, on the West African coast

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a substantial fraction of all
the sardines that are caught

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have plastic particles inside them.

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Scientists don't yet know
how harmful microplastics

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will be when living organisms
consume them.

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They could simply pass through
the gut without causing any harm.

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Or they could transport toxins,

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the effects of which we'll discover
later in the voyage.

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But there's another equally worrying
fate for these tiny fragments.

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Helge's research is revealing
what happens to them

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as they break down even further.

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The end of the chain is something
that we just start to grasp,

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is that these plastics can go
into this nanoplastic phase.

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So basically things that are smaller
than 1,000th of a millimetre,

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so really, really tiny,

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and now we are wondering
whether at least a substantial

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fraction of this lost plastic
that we can't account for,

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whether this has ended
in the nano phase.

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Plastics are designed to be
stable, so they don't break down

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in the environment.

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But Helge believes that at this
tiniest of scales, plastic changes

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and becomes chemically reactive.

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This is such a new discovery that
Helge and his team don't yet know

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exactly what effect these reactive
nanoplastics will have.

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Nano-sized particles can also in
time be transported inside the cell,

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and what happens then is something
that we don't know.

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So we can only make an educated
guess because it's a molecule,

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so it can interact with
the cellular machinery.

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Eventually, this will not happen
only to ocean creatures,

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but the likelihood that we also
have nanoplastic particles

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inside our cells is increasingly
getting higher.

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It's early days, but Helge suspects
that in the long-term, nanoplastics

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could do more harm than the larger
plastic debris

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that's making all the front pages.

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Whilst Helen investigates the
plastic pollution crisis out at sea,

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I'm inland to discover the impact
our actions

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are having on the animals at the top
of the North Sea's food chain.

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Over the past decade, scientists
have noticed an increasing number

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of porpoises and other marine
mammals washing up

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on the North Sea's beaches.

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So I've come to Holland,
where they recover more dead

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porpoises than anywhere else
along the North Sea coast

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to try to find out what's
killing them.

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A week ago, a harbour porpoise
washed up onto a Dutch beach, dead.

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Today, she's at the
University of Utrecht,

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and I'm here to help examine
her corpse,

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to try to discover exactly
how and why she died.

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The harbour porpoise is the most
common marine mammal

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in the North Sea.

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Over 300,000 of them form the top
of the North Sea's food chain.

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Marine biologists regard them
as a sentinel species that can help

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reveal the health of the oceans.

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Whatever is happening in these
waters should be evidenced

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inside their bodies.

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So I'm joining marine biologist
Lonneke IJsseldijk to perform

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a porpoise autopsy, or necropsy.

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Lonneke, hi. Hiya.

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Nice to meet you. And you.

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The aim of the necropsy is
to determine

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an animal's cause of death.

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The first thing I get is this is
just such a beautifully adapted

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animal for the sea. Yeah!
Beautifully smooth and just, yeah.

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Yeah, she is.

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The necropsy begins by ruling out
the most common way

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that humans kill porpoises -

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catching them in fishing nets.

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Almost 2,000 harbour porpoises die

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trapped in nets each year.

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But our female porpoise
doesn't have the telltale marks

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on her skin, so we can be sure
that fishing nets didn't kill her.

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Scientists also know that toxins
humans have put in the North Sea

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can have a dramatic effect
on these mammals.

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So have they impacted the life
of our porpoise?

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To find out, Lonneke's first step
is to run the animal through a

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CT scanner to check for any
congenital deformities.

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The CT scan gives us already
a look inside the animal.

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Oh, that is beautiful.

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Yeah. It gives us a couple of things
that I find very striking.

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Obviously, they don't have hands
like we do - no fingers -

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but still, within the
pectoral fins...

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Yeah. ..you can see that the same
structure as our hands.

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Yeah, absolutely. Yeah.

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That's a five-fingered hand. Yeah.

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A bit like every other mammal.

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It's a mammal.
It's just a marine mammal.

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It's also confirmed that there's no
abnormalities in the bony structure.

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Our porpoise has a healthy
skeleton, and she's young,

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so something has killed her.

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I have to move her onto her side...

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And as we perform an external
assessment, we find our first clue

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as to why she died.

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She looks a bit skinny, erm,
you see,

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so this area is where the
big muscle is -

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the longissimus dorsi, the muscle
that makes sure that she can swim -

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and obviously they need to
have power.

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That looks a bit hollow there.

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It is. A bit too much,
if you ask me.

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So, on first inspection,
you would guess that she's underfed?

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She's underweight, but not
totally emaciated.

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And the reason why may become
apparent when we open her up.

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With a nice sharp knife it will
get us all the way through easily.

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So, to open the animal up...

241
00:14:53,920 --> 00:14:56,280
..just make one cut all the
way down.

242
00:14:57,800 --> 00:14:59,480
Here's the blubber.

243
00:14:59,480 --> 00:15:03,400
Now, that looks to be about
a centimetre thick.

244
00:15:03,400 --> 00:15:05,160
Is that what you'd expect?

245
00:15:05,160 --> 00:15:06,720
Well, it's not enough.

246
00:15:06,720 --> 00:15:10,120
Of course, the fat here is not
just to maintain the shape,

247
00:15:10,120 --> 00:15:12,640
smooth shape, it's an energy store.

248
00:15:12,640 --> 00:15:15,720
Yep. It's an important part of
the health of these animals.

249
00:15:15,720 --> 00:15:18,800
Yes, absolutely.
And that is under what you'd expect.

250
00:15:18,800 --> 00:15:22,960
Yes. So this is evidence that this
animal is underweight, underfed

251
00:15:22,960 --> 00:15:25,040
for some reason? Yes.

252
00:15:27,440 --> 00:15:30,560
To establish why the porpoise
is so thin, we take

253
00:15:30,560 --> 00:15:32,400
a look at what she's been eating.

254
00:15:32,400 --> 00:15:33,680
We're going to leave that

255
00:15:33,680 --> 00:15:35,720
and move... The stomach.
..to this table.

256
00:15:37,560 --> 00:15:40,600
I hope we don't find any
plastic bags, I tell you.

257
00:15:42,800 --> 00:15:45,840
This is the end of the oesophagus,

258
00:15:45,840 --> 00:15:48,280
and we're just going to go
right down.

259
00:15:49,480 --> 00:15:51,480
There's not much in here.

260
00:15:51,480 --> 00:15:52,920
Pretty empty, eh?

261
00:15:52,920 --> 00:15:54,240
Completely empty.

262
00:15:54,240 --> 00:15:56,360
So it hasn't eaten anything
in the last... Well, not

263
00:15:56,360 --> 00:15:57,720
in the last couple of days.

264
00:15:57,720 --> 00:15:59,680
That's not how it's supposed
to be, obviously.

265
00:15:59,680 --> 00:16:01,040
It must have been a bit ill.

266
00:16:01,040 --> 00:16:04,640
This was a starving animal. Yes.

267
00:16:04,640 --> 00:16:06,600
So it was both skinny...
And starving.

268
00:16:06,600 --> 00:16:08,120
..and it was starving.

269
00:16:09,560 --> 00:16:13,400
Our porpoise was struggling
to sustain herself.

270
00:16:13,400 --> 00:16:17,720
We investigate the rest
of her organs to find out why.

271
00:16:17,720 --> 00:16:20,400
I'll start dissecting into
the throat area.

272
00:16:20,400 --> 00:16:23,360
We're now taking the whole
of the trachea

273
00:16:23,360 --> 00:16:25,760
and the larynx and the lungs.

274
00:16:25,760 --> 00:16:28,320
Go right into the lung? Yeah.
You just follow the bronchi,

275
00:16:28,320 --> 00:16:30,080
the main bronchi goes all the way...

276
00:16:30,080 --> 00:16:33,480
Oh! Oh, ho-ho-ho, look what we've
got. Did you find something?

277
00:16:33,480 --> 00:16:35,160
Oh, yeah.

278
00:16:35,160 --> 00:16:36,360
Oh, my goodness.

279
00:16:37,600 --> 00:16:41,480
This thing has got absolutely
loads of parasites.

280
00:16:41,480 --> 00:16:43,880
Where did it come from?
They're right inside there.

281
00:16:43,880 --> 00:16:46,640
Look at that. Oh, my goodness.

282
00:16:46,640 --> 00:16:47,960
The poor thing.

283
00:16:47,960 --> 00:16:51,120
Now, what sort of animals
are these? They're nematodes.

284
00:16:51,120 --> 00:16:52,280
Roundworms?

285
00:16:52,280 --> 00:16:53,840
Yeah, we call them lungworms.

286
00:16:55,480 --> 00:16:57,880
Nasty little worms - or big worms,

287
00:16:57,880 --> 00:16:59,720
right the way... You can see them.

288
00:16:59,720 --> 00:17:02,880
Now, that can't have been very
comfortable for her.

289
00:17:02,880 --> 00:17:05,320
No, erm, of course not.

290
00:17:05,320 --> 00:17:08,720
Can you imagine having something
crawling in your lungs?

291
00:17:08,720 --> 00:17:10,840
That's quite a load, isn't it?

292
00:17:10,840 --> 00:17:12,120
It is, yeah.

293
00:17:12,120 --> 00:17:14,840
But still, for a porpoise,
for an adult porpoise,

294
00:17:14,840 --> 00:17:17,480
we've seen them with a lot more.

295
00:17:17,480 --> 00:17:18,840
Oh, my goodness.

296
00:17:18,840 --> 00:17:21,400
And look at that. That's... Oh!

297
00:17:28,040 --> 00:17:30,560
Most wild mammals have lungworms.

298
00:17:30,560 --> 00:17:33,360
They can spread from porpoise
to porpoise

299
00:17:33,360 --> 00:17:36,400
if they accidentally swallow
infected faeces.

300
00:17:36,400 --> 00:17:39,520
But only when an animal's
immune system is weak

301
00:17:39,520 --> 00:17:42,040
can parasites truly take over.

302
00:17:42,040 --> 00:17:44,200
Now feel this.

303
00:17:44,200 --> 00:17:45,440
Here.

304
00:17:45,440 --> 00:17:48,960
There, you feel a nodule...
Ah, look at that. Look at that.

305
00:17:48,960 --> 00:17:52,840
And that's where the parasites
cause inflammation

306
00:17:52,840 --> 00:17:54,280
to the tissue around.

307
00:17:54,280 --> 00:17:58,040
And this piece of lung is
then not functioning.

308
00:17:58,040 --> 00:18:00,680
So with this animal, we saw
an empty stomach,

309
00:18:00,680 --> 00:18:03,920
no recent feeding.
Parasites in several organs

310
00:18:03,920 --> 00:18:06,200
and lung inflammation.

311
00:18:06,200 --> 00:18:08,240
So, overall, it's not a
healthy animal.

312
00:18:08,240 --> 00:18:09,960
She was definitely ill.

313
00:18:11,080 --> 00:18:14,880
We found clues that our porpoise
may have had a weakened immune

314
00:18:14,880 --> 00:18:20,160
system, which could point towards
something even more concerning.

315
00:18:20,160 --> 00:18:22,400
To find out what's happening,

316
00:18:22,400 --> 00:18:26,480
we send off a blubber sample
to test for toxic chemicals.

317
00:18:27,600 --> 00:18:29,880
So here's a nice piece.

318
00:18:29,880 --> 00:18:32,840
I'm just going to lay it here and
you just... I'll fold it up. Yep.

319
00:18:32,840 --> 00:18:37,520
So what we have in here is
potentially our crucial evidence

320
00:18:37,520 --> 00:18:41,720
that toxins might have been involved
in the demise of this animal.

321
00:18:41,720 --> 00:18:44,960
Yes. Blubber is a good sample
to test.

322
00:18:54,240 --> 00:18:56,120
Back on board the Pelagia,

323
00:18:56,120 --> 00:18:59,240
I'm working with Helge
and his team on the next stage

324
00:18:59,240 --> 00:19:00,840
of our investigation.

325
00:19:00,840 --> 00:19:03,320
We're exploring the depths
of the North Sea for answers

326
00:19:03,320 --> 00:19:07,000
to the spiralling problem
of micro and nanoplastics.

327
00:19:09,240 --> 00:19:11,960
Helge uses the ship's
workhorse instrument,

328
00:19:11,960 --> 00:19:14,440
the CTD rosette, to search for them.

329
00:19:15,880 --> 00:19:21,000
The CTD is such a simple idea,
and yet one of these rosettes

330
00:19:21,000 --> 00:19:24,200
is to an oceanographer what a
telescope is to an astronomer.

331
00:19:24,200 --> 00:19:27,480
This is how we built up our
picture of the oceans,

332
00:19:27,480 --> 00:19:31,480
and thousands of oceanographers
on hundreds of research ships

333
00:19:31,480 --> 00:19:35,040
have sent these tubes down into
the ocean and they've captured

334
00:19:35,040 --> 00:19:38,600
a moment in time and a place
in the ocean, and they've brought

335
00:19:38,600 --> 00:19:41,400
it back and then they've shared
that information with everybody.

336
00:19:42,880 --> 00:19:48,040
24 specially designed bottles allow
the crew to collect water samples

337
00:19:48,040 --> 00:19:50,280
at different depths

338
00:19:50,280 --> 00:19:54,000
to discover how much plastic is here

339
00:19:54,000 --> 00:19:56,720
and how it interacts with
living organisms.

340
00:19:58,320 --> 00:20:00,880
So it's basically a tube
which has a lid at the bottom

341
00:20:00,880 --> 00:20:03,120
and a lid at the top.
So the water just keeps moving...

342
00:20:03,120 --> 00:20:04,680
Exactly. ..through the tube.
Exactly.

343
00:20:04,680 --> 00:20:06,600
It keeps moving through the tube.

344
00:20:06,600 --> 00:20:08,800
Then, at a certain depth,
you can tell the program,

345
00:20:08,800 --> 00:20:10,680
"OK. Fire this bottle.
Fire this bottle."

346
00:20:10,680 --> 00:20:12,080
Clunk - close like that.

347
00:20:15,160 --> 00:20:19,200
And then you have that parcel
of water captured in this tube.

348
00:20:25,280 --> 00:20:29,840
CTD rosettes, just like this one,
have collected plastic fragments

349
00:20:29,840 --> 00:20:32,080
from depths of 4km.

350
00:20:39,320 --> 00:20:41,840
When we retrieve the Pelagia's CTD,

351
00:20:41,840 --> 00:20:44,840
it's not just microplastics
we find inside.

352
00:20:46,120 --> 00:20:50,240
Helge is one of the few scientists
who collects the micro-organisms

353
00:20:50,240 --> 00:20:53,920
found in sea water that interact
with plastic at sea.

354
00:20:55,120 --> 00:20:59,360
Hidden in the water samples
he's collected are marine fungi,

355
00:20:59,360 --> 00:21:03,080
just like these captured
by other research teams.

356
00:21:03,080 --> 00:21:06,080
I associate fungi with, you know,
mushrooms and things in forests.

357
00:21:06,080 --> 00:21:08,800
What are they doing in the ocean
and why are they interesting here?

358
00:21:08,800 --> 00:21:12,800
Fungi are extremely good at breaking
down very complex organic matter

359
00:21:12,800 --> 00:21:16,680
such as wood, for instance. In the
ocean they are quite understudied,

360
00:21:16,680 --> 00:21:19,280
but we have a good...let's
say feeling

361
00:21:19,280 --> 00:21:21,760
that some of these fungi in
the ocean

362
00:21:21,760 --> 00:21:24,480
might be able to also
degrade plastics.

363
00:21:26,080 --> 00:21:29,000
So, basically, these plastic strips
are like little fishing lures,

364
00:21:29,000 --> 00:21:32,680
so we're trying to attract fungi
to settle on the plastic

365
00:21:32,680 --> 00:21:35,680
and then possibly also to use
it as a fuel,

366
00:21:35,680 --> 00:21:37,600
so to eat up the plastic.

367
00:21:37,600 --> 00:21:40,880
You can see here is some
slimy stuff around it

368
00:21:40,880 --> 00:21:44,280
and this is a fungi colony.
This is also a fungi colony.

369
00:21:44,280 --> 00:21:46,760
So these are the guys
that are living on plastic.

370
00:21:46,760 --> 00:21:49,000
Whether they can also make use of
that plastic

371
00:21:49,000 --> 00:21:52,040
we still have to verify, but this
is at least a clear sign

372
00:21:52,040 --> 00:21:54,600
that there is fungi that are
growing

373
00:21:54,600 --> 00:21:57,280
on those plastic pieces
in the ocean.

374
00:21:57,280 --> 00:22:03,280
If it turns out that fungi can eat
away and use plastic as fuel,

375
00:22:03,280 --> 00:22:05,880
does that help?
Personally, this is my hope,

376
00:22:05,880 --> 00:22:09,120
but we don't know. So this is
something that we are trying to

377
00:22:09,120 --> 00:22:12,080
figure out. This eating of plastic
by microbes,

378
00:22:12,080 --> 00:22:15,520
does that take up a substantial part
of the plastic that is being put

379
00:22:15,520 --> 00:22:18,960
into the ocean? And my hope is that,
yes, indeed it is

380
00:22:18,960 --> 00:22:22,960
because it would be very sad
if the ocean is just a trash bin

381
00:22:22,960 --> 00:22:26,320
where stuff is ending up,
but we will never get out.

382
00:22:26,320 --> 00:22:30,480
Helge's ground-breaking work is in
its infancy, but it highlights

383
00:22:30,480 --> 00:22:34,080
how - if we stop dumping
plastic into the sea -

384
00:22:34,080 --> 00:22:38,720
fungi could potentially
make a start at cleaning the ocean.

385
00:22:47,880 --> 00:22:52,880
We are continuing our comprehensive
health check of the North Sea

386
00:22:52,880 --> 00:22:57,240
on one of the major rivers that
feeds into it. The River Thames.

387
00:22:59,200 --> 00:23:02,120
Here on the site of London's
old Docklands,

388
00:23:02,120 --> 00:23:04,600
geochemist Dr Chris Vane is worried

389
00:23:04,600 --> 00:23:08,000
that a chemical banned across the
world 40 years ago

390
00:23:08,000 --> 00:23:10,360
is still harming wildlife at sea

391
00:23:10,360 --> 00:23:12,520
and could even be harming us.

392
00:23:14,360 --> 00:23:16,520
Hi, Chris. Hi there.

393
00:23:16,520 --> 00:23:18,200
Nice to meet you. How are you?

394
00:23:18,200 --> 00:23:21,400
'We're here to take a
sediment core of the Thames mud.'

395
00:23:21,400 --> 00:23:23,640
Come on, then. Let's go and see
some silty mud!

396
00:23:26,600 --> 00:23:31,320
The class of toxic chemicals
we're looking for is called PCBs

397
00:23:31,320 --> 00:23:34,920
or polychlorinated biphenyls.

398
00:23:34,920 --> 00:23:38,440
I'm just going to push this so
that we capture a record

399
00:23:38,440 --> 00:23:41,640
of the pollution through time.

400
00:23:41,640 --> 00:23:44,360
So I'm now going to carefully lift
it out

401
00:23:44,360 --> 00:23:46,760
and then we'll measure the PCBs.

402
00:23:46,760 --> 00:23:51,560
The PCBs have been around since
the 1930s, 1940s.

403
00:23:51,560 --> 00:23:55,880
They were used extensively
in hydraulic fluids and also

404
00:23:55,880 --> 00:24:00,200
in electrical goods, and they're
designed in their chemistry

405
00:24:00,200 --> 00:24:02,400
to be very persistent. Mm.

406
00:24:02,400 --> 00:24:04,640
And that unfortunately is one
of the problems,

407
00:24:04,640 --> 00:24:06,360
is that they don't break down.

408
00:24:06,360 --> 00:24:09,120
Once it's in the environment,
you would have to dredge out

409
00:24:09,120 --> 00:24:11,160
the entire banks of the Thames. Yes.

410
00:24:13,600 --> 00:24:18,000
Despite environmental science's
great victory in getting PCBs

411
00:24:18,000 --> 00:24:19,920
banned in the '70s and '80s,

412
00:24:19,920 --> 00:24:23,160
they are still entering
the environment from rubbish dumps,

413
00:24:23,160 --> 00:24:26,920
from the paint on old bridges,
and from building sites.

414
00:24:26,920 --> 00:24:32,160
Chris has measured almost 2mg
of PCB per kilogram of sediment

415
00:24:32,160 --> 00:24:34,000
from this exact spot -

416
00:24:34,000 --> 00:24:37,560
one of his highest-ever recordings.

417
00:24:37,560 --> 00:24:41,840
What do they do to organisms?
Well, they're harmful to organisms

418
00:24:41,840 --> 00:24:43,720
at certain concentrations.

419
00:24:44,960 --> 00:24:48,560
When PCBs enter living
cells, their chemical structure

420
00:24:48,560 --> 00:24:53,040
allows them to slot inside receptors
usually used by hormones.

421
00:24:54,400 --> 00:24:57,200
If a PCB locks in
to a hormone receptor,

422
00:24:57,200 --> 00:25:00,840
it can block or mimic
the hormone's signal,

423
00:25:00,840 --> 00:25:04,600
confusing the body's finely tuned
messaging system.

424
00:25:06,440 --> 00:25:12,640
The toxicity of PCBs was made clear
in 2016 when a killer whale, known

425
00:25:12,640 --> 00:25:16,920
to scientists as Lulu, was found
dead on a Scottish beach.

426
00:25:19,000 --> 00:25:23,640
Scientists found 20 times the level
of PCBs known to harm marine

427
00:25:23,640 --> 00:25:28,320
mammals in her blubber, more than
enough to make Lulu sterile.

428
00:25:30,200 --> 00:25:34,360
Not a single female in the group
she belongs to has given birth

429
00:25:34,360 --> 00:25:37,760
to a calf in the past 25 years,

430
00:25:37,760 --> 00:25:41,400
and the group filmed in this rare
footage will soon die out.

431
00:25:44,840 --> 00:25:48,680
So how did so much PCB
end up in Lulu's body?

432
00:25:50,720 --> 00:25:55,000
Well, it's all due to a process
called bioaccumulation, which sees

433
00:25:55,000 --> 00:25:58,840
chemicals getting progressively
more and more concentrated

434
00:25:58,840 --> 00:26:01,280
as they pass up the food chain.

435
00:26:01,280 --> 00:26:05,360
Step one begins with tiny animals
and plants called plankton,

436
00:26:05,360 --> 00:26:08,640
and they get the toxic chemicals
in their food on the sediments

437
00:26:08,640 --> 00:26:10,200
on the ocean floor.

438
00:26:10,200 --> 00:26:14,680
Then, along comes fish
and they graze the plankton.

439
00:26:14,680 --> 00:26:17,960
Now, because fish store
these chemicals in their fat,

440
00:26:17,960 --> 00:26:21,280
the chemicals are now locked
into the food chain.

441
00:26:21,280 --> 00:26:24,440
Along comes a penguin and eats
lots of fish.

442
00:26:26,200 --> 00:26:30,760
And then a hungry seal come
along and eats some penguins.

443
00:26:30,760 --> 00:26:35,560
And at each stage, the concentration
of these chemicals is becoming even

444
00:26:35,560 --> 00:26:39,080
more concentrated. And at the top
of the food chain,

445
00:26:39,080 --> 00:26:41,520
you've got big beasts like
killer whales

446
00:26:41,520 --> 00:26:45,520
who consume 300kg of food a day.

447
00:26:45,520 --> 00:26:49,960
And the end result is that
the concentrations of these toxic

448
00:26:49,960 --> 00:26:54,520
chemicals in the fat of a killer
whale are now thousands of times

449
00:26:54,520 --> 00:26:57,120
greater than in the sea water
it swims in.

450
00:26:59,760 --> 00:27:02,960
Because of their persistence
and their bioaccumulation

451
00:27:02,960 --> 00:27:04,520
through the food chain,

452
00:27:04,520 --> 00:27:08,840
40-year-old PCBs are still
poisoning killer whales today.

453
00:27:10,400 --> 00:27:13,840
Scientists predict that, over
the next century, killer whale

454
00:27:13,840 --> 00:27:17,760
populations off Western Europe,
North America's west coast

455
00:27:17,760 --> 00:27:19,520
and Japan will collapse.

456
00:27:20,960 --> 00:27:25,280
These are all places where
the industrial legacy of PCBs

457
00:27:25,280 --> 00:27:26,720
is at its greatest.

458
00:27:30,840 --> 00:27:34,680
But killer whales aren't alone
in eating lots of fish.

459
00:27:34,680 --> 00:27:39,520
A fifth of the protein humanity
consumes comes from seafood,

460
00:27:39,520 --> 00:27:43,960
and as mammals, we share the same
hormone receptors that PCBs

461
00:27:43,960 --> 00:27:46,200
can interfere with.

462
00:27:46,200 --> 00:27:49,640
So could the threat that PCBs
pose to killer whales

463
00:27:49,640 --> 00:27:52,080
pose a threat to us, too?

464
00:27:52,080 --> 00:27:56,680
We humans sit at the top
of a global food chain.

465
00:27:56,680 --> 00:28:00,720
I want to know how much of the
man-made pollution currently

466
00:28:00,720 --> 00:28:04,120
affecting marine life
is making its way into us.

467
00:28:05,720 --> 00:28:06,880
In go the noodles...

468
00:28:06,880 --> 00:28:09,080
One of the most
well-known pollutants

469
00:28:09,080 --> 00:28:13,040
at large in ocean ecosystems
is the heavy metal, mercury.

470
00:28:14,320 --> 00:28:19,640
Like PCBs, mercury is a product
of human industry and can

471
00:28:19,640 --> 00:28:22,400
bioaccumulate in top
marine predators.

472
00:28:22,400 --> 00:28:25,000
But there's more mercury in a single

473
00:28:25,000 --> 00:28:28,920
tuna steak than PCBs,
so it's easier to test for.

474
00:28:31,080 --> 00:28:34,920
I'm doing an experiment today to see
if even this small amount of tuna

475
00:28:34,920 --> 00:28:38,920
can affect the level of
pollutants in my blood.

476
00:28:38,920 --> 00:28:42,600
Mercury poisoning can cause brain
damage, and a baby developing

477
00:28:42,600 --> 00:28:46,400
in the womb is particularly
vulnerable to its effects.

478
00:28:47,560 --> 00:28:49,960
Oh, now... That is so good.

479
00:28:52,800 --> 00:28:56,120
This is the third tuna steak
I've had in a week,

480
00:28:56,120 --> 00:29:00,320
and that's just one steak more
than is recommended by the NHS

481
00:29:00,320 --> 00:29:03,480
if you're pregnant.
For ten days before this,

482
00:29:03,480 --> 00:29:07,960
I didn't eat any fish or rice,
so any mercury in my blood

483
00:29:07,960 --> 00:29:12,600
should have been taken up by my
organs or flushed down the toilet.

484
00:29:16,280 --> 00:29:19,560
Last week, I had my blood
mercury levels measured

485
00:29:19,560 --> 00:29:21,760
at the Charing Cross Hospital
in London.

486
00:29:23,680 --> 00:29:26,240
I'm supposed to say it's only
a small scratch...

487
00:29:26,240 --> 00:29:29,760
Today, Dr Nick Martin is
measuring them again.

488
00:29:29,760 --> 00:29:32,240
I brought my sample for you.
Thank you.

489
00:29:32,240 --> 00:29:35,320
So this first sample
is the baseline sample,

490
00:29:35,320 --> 00:29:37,280
the one I gave a week ago

491
00:29:37,280 --> 00:29:40,440
when I hadn't eaten any fish
or rice for ten days,

492
00:29:40,440 --> 00:29:43,560
and that should be negligible.

493
00:29:43,560 --> 00:29:48,200
This one here is the first sample.
Right. 7.6.

494
00:29:48,200 --> 00:29:52,160
And this one here is the second
sample, so 18.9.

495
00:29:52,160 --> 00:29:55,120
The three tuna steaks I've eaten
in the past week appear

496
00:29:55,120 --> 00:29:58,720
to have doubled the amount
of mercury in my blood.

497
00:29:58,720 --> 00:30:01,320
Although it's still well
within safe levels,

498
00:30:01,320 --> 00:30:04,880
this is evidence that we
bioaccumulate toxins

499
00:30:04,880 --> 00:30:06,560
just like killer whales.

500
00:30:07,600 --> 00:30:08,840
So it's an increase,

501
00:30:08,840 --> 00:30:11,520
it's a slight increase, still
within what you'd expect

502
00:30:11,520 --> 00:30:16,280
in a normal range, but it does show
that the tuna contain mercury

503
00:30:16,280 --> 00:30:20,080
that I have now taken onboard.
Yes, that's correct.

504
00:30:21,800 --> 00:30:24,880
So it's very clear that the mercury
that was in the fish that I ate

505
00:30:24,880 --> 00:30:27,520
has made its way into me.

506
00:30:27,520 --> 00:30:33,160
What concerns me more, though,
is chemicals like PCBs. About 80%

507
00:30:33,160 --> 00:30:37,280
of the PCBs that have ever
been produced are unaccounted for.

508
00:30:37,280 --> 00:30:40,480
They're still in the environment
waiting to leach their way out.

509
00:30:42,440 --> 00:30:47,080
Even though PCBs were banned many
years ago, they're still finding

510
00:30:47,080 --> 00:30:49,560
their way into the sea and into us.

511
00:30:51,560 --> 00:30:55,200
In the past 40 years, the rate
of diabetes around the world

512
00:30:55,200 --> 00:30:59,480
has doubled, and the sperm counts
of men in the Western world

513
00:30:59,480 --> 00:31:01,080
have fallen by a half.

514
00:31:03,080 --> 00:31:05,960
Scientists worry that both
these trends could be linked

515
00:31:05,960 --> 00:31:10,960
to the disruption to our hormones
caused by PCBs and other

516
00:31:10,960 --> 00:31:13,080
hormone-disrupting pollutants.

517
00:31:14,600 --> 00:31:18,680
Unless we find a way to stop
these chemicals entering the oceans,

518
00:31:18,680 --> 00:31:21,440
the problem is only going
to get worse.

519
00:31:28,120 --> 00:31:31,080
Back on the ship, Helge
believes there's a connection

520
00:31:31,080 --> 00:31:35,160
between the spread of plastics
in the ocean and the spread of toxic

521
00:31:35,160 --> 00:31:36,560
chemicals like PCBs.

522
00:31:38,240 --> 00:31:42,040
So he's helping to create a map
showing the spread of plastics

523
00:31:42,040 --> 00:31:43,880
around the North Sea.

524
00:31:43,880 --> 00:31:46,800
At every station
we are doing this kind of fishing,

525
00:31:46,800 --> 00:31:50,880
so, therefore, we are filling
this blank map with new data.

526
00:31:53,000 --> 00:31:59,000
Helge suspects that microplastics
can absorb toxic chemicals like PCBs

527
00:31:59,000 --> 00:32:01,480
and act as a kind of raft
that can carry them

528
00:32:01,480 --> 00:32:03,720
on the ocean's currents.

529
00:32:03,720 --> 00:32:07,720
Some of these compounds
that are in plastic,

530
00:32:07,720 --> 00:32:11,240
like, for instance, flame retardants
or so, these can also leach

531
00:32:11,240 --> 00:32:14,520
out of the plastic and then go
into the food chain.

532
00:32:14,520 --> 00:32:20,400
This time-lapse shows how plastic
spread when, in 2019,

533
00:32:20,400 --> 00:32:22,760
a ship off Germany's northern coast

534
00:32:22,760 --> 00:32:27,000
lost more than 340 containers
in high seas.

535
00:32:27,000 --> 00:32:31,120
It reveals where the UK's plastic
waste and toxic chemicals

536
00:32:31,120 --> 00:32:33,760
like PCBs will likely end up.

537
00:32:33,760 --> 00:32:39,880
In one of the most sensitive marine
environments on Earth - the Arctic.

538
00:32:41,840 --> 00:32:45,360
Scientists studying polar bears in
the Arctic believe that pollutants

539
00:32:45,360 --> 00:32:49,360
such as PCBs are making
it harder for them to reproduce.

540
00:32:52,600 --> 00:32:56,760
So far, our ocean autopsy
has demonstrated the huge impact

541
00:32:56,760 --> 00:33:00,120
of human industry on significant
parts of the North Sea.

542
00:33:02,520 --> 00:33:06,520
We find micro and nanoplastics not
just on the surface,

543
00:33:06,520 --> 00:33:09,680
but all the way to the sea floor.

544
00:33:10,840 --> 00:33:15,000
And human-made pollutants
like mercury and PCBs

545
00:33:15,000 --> 00:33:19,440
can travel from land to sea and
enter the marine food chain.

546
00:33:21,520 --> 00:33:25,920
Now, there's evidence that our
global impact is so heavy

547
00:33:25,920 --> 00:33:27,920
that we're depriving our sea

548
00:33:27,920 --> 00:33:31,160
of the very thing life needs
to survive - oxygen.

549
00:33:33,120 --> 00:33:34,840
This is a lovely little globe,

550
00:33:34,840 --> 00:33:37,080
which is a self-sustaining
ecosystem,

551
00:33:37,080 --> 00:33:39,240
so that means everything in here
is recycled.

552
00:33:39,240 --> 00:33:40,880
There's only a few things in there.

553
00:33:40,880 --> 00:33:42,600
There's these tiny little shrimp,

554
00:33:42,600 --> 00:33:46,480
there's algae, and there's
bacteria. And everything

555
00:33:46,480 --> 00:33:48,880
that those little shrimp
and the algae and bacteria need

556
00:33:48,880 --> 00:33:51,120
for life is just cycling
round and round.

557
00:33:51,120 --> 00:33:54,240
One of the most important
things in here is oxygen,

558
00:33:54,240 --> 00:33:57,120
and so there'll be some oxygen
in the air up here,

559
00:33:57,120 --> 00:33:58,680
some in the water.

560
00:33:58,680 --> 00:34:01,880
When they photosynthesize,
the plants will give it out

561
00:34:01,880 --> 00:34:04,920
and then the shrimp will breathe
it back in when they respire,

562
00:34:04,920 --> 00:34:07,360
and then it'll go round and round.

563
00:34:07,360 --> 00:34:11,440
And so, in theory, these little
shrimp have everything they need

564
00:34:11,440 --> 00:34:14,800
for life, all locked up in that.
All they need is some sunlight.

565
00:34:16,840 --> 00:34:20,760
Just like the life in this globe,
life on Earth forms one

566
00:34:20,760 --> 00:34:22,880
interconnected ecosystem.

567
00:34:22,880 --> 00:34:27,080
One of the crucial features
in this global ecology

568
00:34:27,080 --> 00:34:30,120
is the level of oxygen in the ocean.

569
00:34:30,120 --> 00:34:33,240
If you think about nature harvesting
the sun's energy, we normally think

570
00:34:33,240 --> 00:34:35,360
about trees and meadows,

571
00:34:35,360 --> 00:34:39,040
but that's only half the story,
because fully half of Earth's

572
00:34:39,040 --> 00:34:41,280
sun harvest comes through these

573
00:34:41,280 --> 00:34:43,520
and these are the phytoplankton.

574
00:34:43,520 --> 00:34:45,840
They're tiny - too small to see
individually,

575
00:34:45,840 --> 00:34:48,200
but they're doing exactly
the same job.

576
00:34:48,200 --> 00:34:49,680
And it's an amazing contrast.

577
00:34:49,680 --> 00:34:53,280
If you think about a tree,
it's a huge organism that lives

578
00:34:53,280 --> 00:34:54,800
for tens or hundreds of years.

579
00:34:54,800 --> 00:34:56,920
It's fixed in one place.

580
00:34:56,920 --> 00:35:01,320
And yet these are the rainforests
of the ocean.

581
00:35:01,320 --> 00:35:03,880
Together, these tiny life forms

582
00:35:03,880 --> 00:35:07,480
supply more than 50% of
planet Earth's oxygen.

583
00:35:08,520 --> 00:35:10,760
That's more than double
the oxygen produced

584
00:35:10,760 --> 00:35:14,200
by all the world's rainforests
combined.

585
00:35:14,200 --> 00:35:17,760
The plankton forms blooms
that are so large,

586
00:35:17,760 --> 00:35:20,160
we can even see them from space.

587
00:35:21,400 --> 00:35:25,480
What's going on here is that
there is a bloom, a phytoplankton

588
00:35:25,480 --> 00:35:29,400
bloom, which means that loads
of tiny single-celled plant-like

589
00:35:29,400 --> 00:35:32,720
organisms have suddenly got
the right conditions to grow

590
00:35:32,720 --> 00:35:34,200
all at the same time.

591
00:35:34,200 --> 00:35:37,080
And the reason for that is
that cold, nutrient-rich water

592
00:35:37,080 --> 00:35:38,760
has come up to meet the sunlight

593
00:35:38,760 --> 00:35:41,520
and everything is there
for life to explode.

594
00:35:42,560 --> 00:35:47,000
These satellite photographs show
plankton blooms in the Yellow Sea

595
00:35:47,000 --> 00:35:48,120
off South Korea.

596
00:35:49,920 --> 00:35:54,000
In the Bering Strait between
Russia and Alaska.

597
00:35:54,000 --> 00:35:58,560
And in the Black Sea,
off Turkey's northern shore.

598
00:35:58,560 --> 00:36:03,120
Remarkably, these plankton blooms
stretch across the world's oceans

599
00:36:03,120 --> 00:36:05,840
and pulse in and out with
the seasons.

600
00:36:05,840 --> 00:36:09,040
So here we are in summer now
in the northern hemisphere,

601
00:36:09,040 --> 00:36:10,320
there's almost no ice.

602
00:36:10,320 --> 00:36:12,840
And then it goes into winter
and there's a little...

603
00:36:12,840 --> 00:36:14,200
..extra little puff of life.

604
00:36:14,200 --> 00:36:18,160
And then when the spring comes,
suddenly the ocean lights up.

605
00:36:19,200 --> 00:36:21,040
So every year there's a cycle
like this.

606
00:36:21,040 --> 00:36:23,120
This is the Earth breathing.

607
00:36:25,560 --> 00:36:29,200
But these cycles are knocked
out of kilter when the nutrients

608
00:36:29,200 --> 00:36:33,840
contained in fertilisers run off
from farms and feed super blooms

609
00:36:33,840 --> 00:36:35,680
of plankton in the ocean.

610
00:36:37,400 --> 00:36:41,280
When these plankton die,
they sink and rot,

611
00:36:41,280 --> 00:36:43,960
consuming the sea's vital oxygen.

612
00:36:46,240 --> 00:36:51,120
In 2019, an 8,000-square-mile
stretch of sea at the mouth

613
00:36:51,120 --> 00:36:55,200
of the River Mississippi
was classified as a dead zone,

614
00:36:55,200 --> 00:36:59,040
and scientists fear that
a combination of excess nutrients

615
00:36:59,040 --> 00:37:04,080
and warmer waters could see oxygen
levels drop so much in many parts

616
00:37:04,080 --> 00:37:07,480
of the ocean that creatures
like sharks and turtles

617
00:37:07,480 --> 00:37:10,560
will suffocate, while jellyfish
will thrive.

618
00:37:13,880 --> 00:37:18,320
If we can breed new strains of crops
and develop more sustainable farming

619
00:37:18,320 --> 00:37:21,360
methods, there's hope
that we'll be able to spray

620
00:37:21,360 --> 00:37:23,600
less fertiliser onto our fields

621
00:37:23,600 --> 00:37:26,920
and revitalise the dead zones
killing our seas.

622
00:37:32,520 --> 00:37:36,120
In the necropsy lab, we're taking
a look at a wonder of the marine

623
00:37:36,120 --> 00:37:40,920
world - how a porpoise is able
to navigate the darkness

624
00:37:40,920 --> 00:37:42,200
of the North Sea.

625
00:37:47,360 --> 00:37:50,520
Toothed whales like this harbour
porpoise have swum in the oceans

626
00:37:50,520 --> 00:37:52,080
for millions of years

627
00:37:52,080 --> 00:37:55,320
and, in that time, the have evolved
a unique way of perceiving

628
00:37:55,320 --> 00:37:57,000
the world - echolocation.

629
00:37:59,360 --> 00:38:02,720
Echolocation is a porpoise's
sixth sense.

630
00:38:02,720 --> 00:38:05,840
They use it to hunt, socialise
and navigate.

631
00:38:07,960 --> 00:38:11,400
I'm investigating how this
remarkable sense works.

632
00:38:11,400 --> 00:38:14,520
Right! Now, this is where it gets
really interesting.

633
00:38:17,040 --> 00:38:20,160
Here is the head of the porpoise,
and you've cut

634
00:38:20,160 --> 00:38:23,920
right down the middle. Yes.
So we can, very carefully...

635
00:38:23,920 --> 00:38:28,960
Open it up. ..reveal what's really
happening in here.

636
00:38:28,960 --> 00:38:32,800
The blowhole
is essentially our nose. Yeah.

637
00:38:32,800 --> 00:38:35,840
So it's just moved up to the top.
Just below the blowhole,

638
00:38:35,840 --> 00:38:39,440
we have some specialised
structures called phonic lips.

639
00:38:39,440 --> 00:38:43,120
These are like our vocal cords,
but not quite the same

640
00:38:43,120 --> 00:38:44,800
cos it's a different structure,

641
00:38:44,800 --> 00:38:48,560
but they're able to make
these vibrate. Yes.

642
00:38:48,560 --> 00:38:51,640
And produce a clicking noise
or a bzzz noise. Yep.

643
00:38:51,640 --> 00:38:53,240
At very high frequency.

644
00:38:53,240 --> 00:38:56,960
It's a high-pitched buzz or a series
of clicks that are sent forward

645
00:38:56,960 --> 00:39:02,320
off the skull here through this fat
tissue here, and projected forward

646
00:39:02,320 --> 00:39:05,560
either in a wide beam or a
small beam.

647
00:39:05,560 --> 00:39:10,840
And it's then returned
from the object along this acoustic

648
00:39:10,840 --> 00:39:17,280
fat that runs along the jaw
into the auditory system here.

649
00:39:17,280 --> 00:39:19,640
These animals see with sound. Yep.

650
00:39:19,640 --> 00:39:23,160
And the closer the subject
comes, the quicker the clicks

651
00:39:23,160 --> 00:39:25,480
will reach and bounce.

652
00:39:25,480 --> 00:39:27,600
Ping, ping! That is sent forward.

653
00:39:27,600 --> 00:39:30,240
Ping! And then ping, it returns
from the fish,

654
00:39:30,240 --> 00:39:32,600
and if it's far away
it'll be a longer return.

655
00:39:32,600 --> 00:39:35,640
If it's shorter, it will be
ping-ping, ping-ping.

656
00:39:35,640 --> 00:39:40,320
And it's so finely tuned that they
can tell what other animals

657
00:39:40,320 --> 00:39:43,640
are there, who they are, if it's
their mates or a calf.

658
00:39:43,640 --> 00:39:48,600
They can tell prey, how far away
it is, what the prey is, how fast

659
00:39:48,600 --> 00:39:53,680
it's going, which way it's going,
and all in total darkness.

660
00:39:53,680 --> 00:39:55,320
Now that is a super sense.

661
00:39:57,400 --> 00:40:01,360
Porpoise and dolphin echolocation
gives these creatures abilities

662
00:40:01,360 --> 00:40:03,560
that we can only marvel at.

663
00:40:03,560 --> 00:40:08,120
They can listen to the reflected
clicks of other animals

664
00:40:08,120 --> 00:40:10,360
to check out what their neighbours
are looking at.

665
00:40:12,000 --> 00:40:14,880
And some reports suggest
that they can even see

666
00:40:14,880 --> 00:40:18,800
inside each other, using their
clicks as ultrasound

667
00:40:18,800 --> 00:40:21,520
to look at unborn pups in the womb.

668
00:40:22,840 --> 00:40:24,960
Could our actions in the sea

669
00:40:24,960 --> 00:40:28,000
compromise these remarkable
abilities?

670
00:40:33,880 --> 00:40:39,400
Over 3,500 wind turbines
and almost 200 oil rigs

671
00:40:39,400 --> 00:40:43,120
have transformed the North Sea
into an industrial landscape.

672
00:40:46,080 --> 00:40:49,960
With so much industry, I want
to hear for myself just how noisy

673
00:40:49,960 --> 00:40:52,400
the water is beneath the surface.

674
00:40:54,680 --> 00:40:57,680
To do that, we'll need to get
as far away from the sound

675
00:40:57,680 --> 00:40:59,280
of our ship as we can.

676
00:41:03,760 --> 00:41:08,600
So I'm now in a small boat, maybe
500 metres away from the Pelagia,

677
00:41:08,600 --> 00:41:12,200
and it's beautifully peaceful
and really quiet.

678
00:41:12,200 --> 00:41:15,200
And the reason I'm here
is that, even though it's quiet

679
00:41:15,200 --> 00:41:18,280
and peaceful up here, it doesn't
necessarily mean that it's quiet

680
00:41:18,280 --> 00:41:20,000
and peaceful down below.

681
00:41:20,000 --> 00:41:22,280
And the reason for that is
that the ocean surface acts

682
00:41:22,280 --> 00:41:25,480
like a mirror for sound. Sound
from the air comes down and bounces

683
00:41:25,480 --> 00:41:28,480
off the ocean and goes back up,
and sound from underneath comes up,

684
00:41:28,480 --> 00:41:31,680
hits the ocean's surface
and bounces back down.

685
00:41:31,680 --> 00:41:35,600
So the ocean surface is effectively
a barrier for almost all sound,

686
00:41:35,600 --> 00:41:38,040
so we have no idea what's
going on down there

687
00:41:38,040 --> 00:41:40,440
and it is a different acoustic
world.

688
00:41:40,440 --> 00:41:44,760
But you can listen in with the
help of a bit of technology.

689
00:41:44,760 --> 00:41:47,840
So what I've got here is
a hydrophone, it's an underwater

690
00:41:47,840 --> 00:41:51,720
microphone, and it's attached
to a little device here

691
00:41:51,720 --> 00:41:56,120
that will play out in real time
what's happening under the waves.

692
00:41:56,120 --> 00:41:58,800
So this is our ear into the ocean,

693
00:41:58,800 --> 00:42:01,720
and we're going to see what there
is to listen to round here.

694
00:42:10,240 --> 00:42:12,560
So the first sound is the sound
of bubbles being formed

695
00:42:12,560 --> 00:42:17,440
as it splashed, and I've got quite
a lot of cable here.

696
00:42:17,440 --> 00:42:19,000
DEEP PING

697
00:42:19,000 --> 00:42:20,320
That's interesting.

698
00:42:21,880 --> 00:42:23,800
PINGING

699
00:42:23,800 --> 00:42:26,880
So, as it goes down,
there's a new sound.

700
00:42:26,880 --> 00:42:28,720
What's that?

701
00:42:28,720 --> 00:42:30,280
PINGING CONTINUES

702
00:42:30,280 --> 00:42:32,720
You can hear this, "Ooh."

703
00:42:33,760 --> 00:42:34,920
PING

704
00:42:34,920 --> 00:42:36,000
SHE MIMICS

705
00:42:36,000 --> 00:42:38,040
And it's really clear on here,
so something

706
00:42:38,040 --> 00:42:40,520
down there is making a sort of
deep pinging noise,

707
00:42:40,520 --> 00:42:44,280
and I think that is too low a
frequency to be our ship's

708
00:42:44,280 --> 00:42:46,960
multi-beam. So there's an oil
platform just over there -

709
00:42:46,960 --> 00:42:49,480
it might be they're testing
something and it's doing that.

710
00:42:49,480 --> 00:42:51,960
It is straight out of Star Wars.

711
00:42:51,960 --> 00:42:53,160
PINGING CONTINUES

712
00:42:53,160 --> 00:42:55,280
It must sound even weirder to a
fish, that.

713
00:42:59,360 --> 00:43:02,840
Human-generated sounds
like the noise I've just recorded

714
00:43:02,840 --> 00:43:06,080
have an impact on marine
animal behaviour.

715
00:43:06,080 --> 00:43:08,120
One of the saddest things
about noise pollution

716
00:43:08,120 --> 00:43:11,440
is that actually things like
porpoises, for example, they use

717
00:43:11,440 --> 00:43:13,720
sound to communicate all the time

718
00:43:13,720 --> 00:43:17,280
and, first of all, if it's noisy,
they can't hear each other

719
00:43:17,280 --> 00:43:18,760
but, secondly, just like us,

720
00:43:18,760 --> 00:43:21,000
if you hear a really loud
noise, it's stressful.

721
00:43:21,000 --> 00:43:23,280
They tend to move away from it.

722
00:43:24,640 --> 00:43:27,440
Our actions are making it
more difficult for porpoises

723
00:43:27,440 --> 00:43:31,200
and dolphins to sustain
and reproduce in noisy waters.

724
00:43:33,120 --> 00:43:36,120
And the loud booms made
when we hammer the foundations

725
00:43:36,120 --> 00:43:39,760
of wind turbines into the seabed
can deafen them.

726
00:43:42,920 --> 00:43:47,440
Thousands of porpoises washed up on
North Sea beaches just last year.

727
00:43:49,120 --> 00:43:53,160
We've sent away blubber samples
of our porpoise because we suspect

728
00:43:53,160 --> 00:43:56,640
that chemical pollution
could be partly to blame.

729
00:43:58,000 --> 00:44:00,160
And as our necropsy advances,

730
00:44:00,160 --> 00:44:02,120
it becomes clear that we may

731
00:44:02,120 --> 00:44:05,200
have more than one porpoise
death to explain.

732
00:44:05,200 --> 00:44:08,280
Oh, now, what happened there?

733
00:44:08,280 --> 00:44:11,080
You just pressed the mammary gland

734
00:44:11,080 --> 00:44:15,480
and we have a little bit of white
fluid. Milk came out.

735
00:44:15,480 --> 00:44:17,320
Milk. That means she had a calf.

736
00:44:17,320 --> 00:44:19,160
She was lactating for a calf,

737
00:44:19,160 --> 00:44:21,640
which unfortunately
can't go without milk,

738
00:44:21,640 --> 00:44:26,240
so I'm afraid that means
that she was either unsuccessful

739
00:44:26,240 --> 00:44:28,760
or at least her calf did
not survive.

740
00:44:28,760 --> 00:44:31,120
So we potentially have two animals.

741
00:44:31,120 --> 00:44:34,360
Yeah, unfortunately, I'm afraid
that's the message.

742
00:44:34,360 --> 00:44:37,160
That's sad. That's very sad.

743
00:44:37,160 --> 00:44:41,000
So the PCBs, if they're in this
animal, are going to be passed

744
00:44:41,000 --> 00:44:43,200
directly to the calf in the milk.

745
00:44:43,200 --> 00:44:46,880
Yes. Adult females, as she is,
can off-load

746
00:44:46,880 --> 00:44:49,120
and this is the way of off-loading.

747
00:44:49,120 --> 00:44:52,320
The off-load would mean they can
get rid of their PCBs

748
00:44:52,320 --> 00:44:54,880
by potentially feeding them...
Feeding them to the calf.

749
00:44:54,880 --> 00:44:56,520
That's a tragedy, isn't it?

750
00:44:56,520 --> 00:44:59,800
Because PCBs dissolve in fat,

751
00:44:59,800 --> 00:45:03,000
our porpoise will have inadvertently
off-loaded them

752
00:45:03,000 --> 00:45:04,880
into her first calf's milk.

753
00:45:06,560 --> 00:45:10,640
When a new mum starts to
breast-feed, as much as 80%

754
00:45:10,640 --> 00:45:15,920
of the PCBs in her body fat can
pass into the fat in her milk,

755
00:45:15,920 --> 00:45:19,160
and mums can also transfer
PCBs directly

756
00:45:19,160 --> 00:45:22,440
to a developing foetus in the womb.

757
00:45:24,400 --> 00:45:27,840
This is the left side of the
uterus coming out,

758
00:45:27,840 --> 00:45:33,080
and, well, unfortunately
I have to tell you that it feels

759
00:45:33,080 --> 00:45:35,080
like there is actually
something in it.

760
00:45:35,080 --> 00:45:37,640
Don't squeeze too hard.
Just softly. You feel...?

761
00:45:38,640 --> 00:45:41,200
Yeah. Yeah. Yeah, yeah, yeah.

762
00:45:41,200 --> 00:45:43,600
Yeah, yeah. Yeah.

763
00:45:43,600 --> 00:45:45,440
So she is pregnant.

764
00:45:45,440 --> 00:45:48,240
She was. So it's a very sad case,

765
00:45:48,240 --> 00:45:50,720
but, yeah, let's, uh,

766
00:45:50,720 --> 00:45:52,640
let's figure out what's going on.

767
00:45:52,640 --> 00:45:55,120
Obviously, it's very... Oh, I can...
Oh, look, look.

768
00:45:55,120 --> 00:45:56,480
Oh, yeah. There it is.

769
00:45:56,480 --> 00:46:00,680
Aww. Very fragile, still in its sac.

770
00:46:00,680 --> 00:46:04,800
Look. Tiny little foetus.

771
00:46:04,800 --> 00:46:07,040
It's tiny. Mm.

772
00:46:07,040 --> 00:46:09,160
How old would you say that is?

773
00:46:09,160 --> 00:46:12,160
So this will be... A few weeks?

774
00:46:12,160 --> 00:46:16,400
No, a little bit more. I would
say maybe up to two months.

775
00:46:16,400 --> 00:46:19,440
What-what a mess. What a mess!

776
00:46:19,440 --> 00:46:22,120
So there's two
things that the PCBs do.

777
00:46:22,120 --> 00:46:25,720
On one hand they can produce
reproduction failure,

778
00:46:25,720 --> 00:46:28,520
and we have strong indications
that that was the case.

779
00:46:28,520 --> 00:46:32,200
On the other hand, it's
dysfunctioning of the immune system,

780
00:46:32,200 --> 00:46:35,920
so high parasite loads. With
that also general debilitation

781
00:46:35,920 --> 00:46:38,560
from not eating and being emaciated.

782
00:46:38,560 --> 00:46:44,280
So the animal was healthy enough
to be pregnant, but clearly not

783
00:46:44,280 --> 00:46:46,440
healthy enough to carry it through.

784
00:46:49,520 --> 00:46:53,200
Our porpoise was in a weakened state
because she was trying to eat

785
00:46:53,200 --> 00:46:57,440
for herself, her newborn pup
and the foetus in her womb.

786
00:46:59,600 --> 00:47:02,080
We're nearing the end
of our investigation today

787
00:47:02,080 --> 00:47:03,880
into how this animal died,

788
00:47:03,880 --> 00:47:08,000
and already we can see that she
was underweight for her size.

789
00:47:08,000 --> 00:47:11,640
She hadn't eaten anything
for a few days before she died.

790
00:47:11,640 --> 00:47:14,400
She had a pregnancy,
which had obviously failed,

791
00:47:14,400 --> 00:47:17,160
and she had parasites in her lungs.

792
00:47:17,160 --> 00:47:19,400
All in all, a pretty stark picture.

793
00:47:22,880 --> 00:47:25,840
A week later, I've returned home
to England

794
00:47:25,840 --> 00:47:28,680
and Lonneke has
the toxicology results.

795
00:47:30,680 --> 00:47:33,280
Hi, Lonneke. Hi, George.

796
00:47:33,280 --> 00:47:37,760
Now, we were particularly interested
in seeing how much PCB

797
00:47:37,760 --> 00:47:40,400
she had in her.
What were the results?

798
00:47:40,400 --> 00:47:44,440
The PCB levels were relatively
low in the blubber of this animal.

799
00:47:44,440 --> 00:47:47,400
Through her lactation
she was able to off-load,

800
00:47:47,400 --> 00:47:50,680
but it does mean that the calf
that's suckling is getting

801
00:47:50,680 --> 00:47:54,360
high doses of these PCBs in,
at a very young age, so...

802
00:47:54,360 --> 00:47:59,520
And that means that her newborn,
who is extremely vulnerable,

803
00:47:59,520 --> 00:48:03,080
will get an enormous amount of
this stuff.

804
00:48:03,080 --> 00:48:06,320
You know, bang,
right at the start of her life.

805
00:48:06,320 --> 00:48:09,240
First calf especially gets
the highest doses of something

806
00:48:09,240 --> 00:48:12,560
like a chemical cocktail,
which comes through the milk.

807
00:48:13,880 --> 00:48:16,480
Lonneke's necropsies show
that one in five

808
00:48:16,480 --> 00:48:19,560
female porpoises found
on the North Sea's beaches

809
00:48:19,560 --> 00:48:21,920
have suffered a failed pregnancy.

810
00:48:23,400 --> 00:48:27,560
And she believes that the harmful
effects of PCBs kill most

811
00:48:27,560 --> 00:48:31,480
first-born porpoises in the
North Sea prematurely,

812
00:48:31,480 --> 00:48:34,880
including the first-born calf
of our porpoise.

813
00:48:36,760 --> 00:48:42,840
How do we stop PCBs from getting
into the seas in the first place?

814
00:48:42,840 --> 00:48:44,600
I mean, they're persistent
pollutants.

815
00:48:44,600 --> 00:48:46,880
They persist even though
that they've been banned.

816
00:48:46,880 --> 00:48:48,800
It's a very difficult question

817
00:48:48,800 --> 00:48:51,640
and there's not a straightforward
way to go.

818
00:48:51,640 --> 00:48:55,440
The $64,000 question, Lonneke,
how did she die?

819
00:48:55,440 --> 00:48:57,400
I think the emaciation
was something

820
00:48:57,400 --> 00:49:01,480
that really was the main
finding. Being pregnant

821
00:49:01,480 --> 00:49:04,240
but also lactating means
that she really has to invest

822
00:49:04,240 --> 00:49:07,800
in her offspring, and that might
have come at her own cost, so.

823
00:49:07,800 --> 00:49:10,640
OK, Lonneke, thank you very much.

824
00:49:10,640 --> 00:49:12,280
Thank you.

825
00:49:16,320 --> 00:49:19,720
The necropsy has revealed
that our porpoise lost weight

826
00:49:19,720 --> 00:49:24,200
as she struggled to feed both her
foetus and her newborn calf,

827
00:49:24,200 --> 00:49:27,960
becoming weaker and weaker
until she eventually died.

828
00:49:29,800 --> 00:49:34,040
Although we can't blame PCBs
directly for her death, or say

829
00:49:34,040 --> 00:49:38,280
exactly what killed her, we do know
that PCBs in the North Sea

830
00:49:38,280 --> 00:49:41,400
are having an impact on calf
survival.

831
00:49:41,400 --> 00:49:45,680
And the evidence we've seen here
indicates that PCBs

832
00:49:45,680 --> 00:49:49,160
could have been responsible
for her first-born's death

833
00:49:49,160 --> 00:49:52,040
as she off-loaded PCBs
into her milk.

834
00:49:54,040 --> 00:49:57,400
We're finally beginning
to understand the damage plastics

835
00:49:57,400 --> 00:50:00,600
and PCBs are inflicting
on life in the sea.

836
00:50:05,720 --> 00:50:10,000
But there is another set
of chemicals that we use every day

837
00:50:10,000 --> 00:50:12,840
that are also toxifying our water.

838
00:50:14,280 --> 00:50:18,000
Scientists are now realising
that other harmful chemicals

839
00:50:18,000 --> 00:50:20,600
are making their way into our
waterways.

840
00:50:20,600 --> 00:50:25,240
Chemicals deliberately designed
to be biologically active -

841
00:50:25,240 --> 00:50:26,840
pharmaceutical drugs.

842
00:50:31,080 --> 00:50:34,400
Alistair Boxall is professor
of environmental chemistry

843
00:50:34,400 --> 00:50:36,360
at the University of York.

844
00:50:38,040 --> 00:50:41,680
He runs a project measuring
the drugs flowing from rivers

845
00:50:41,680 --> 00:50:44,120
into the sea in 105 countries.

846
00:50:47,520 --> 00:50:51,200
I've joined Alistair at Hampton
Court Bridge in south west London

847
00:50:51,200 --> 00:50:55,040
to find out how many pharmaceuticals
make it into the River Thames

848
00:50:55,040 --> 00:50:57,520
and ultimately into the North Sea.

849
00:51:02,000 --> 00:51:05,440
So, here's a good spot.
Yeah, this is perfect.

850
00:51:05,440 --> 00:51:10,440
Alistair samples the water for
61 different pharmaceuticals,

851
00:51:10,440 --> 00:51:13,560
just a fraction of the 1,900
medications

852
00:51:13,560 --> 00:51:15,600
licensed for use in the UK.

853
00:51:16,840 --> 00:51:21,440
How do these compounds actually
make their way into the Thames?

854
00:51:21,440 --> 00:51:25,400
When we take a pharmaceutical,
we will take it into our body,

855
00:51:25,400 --> 00:51:28,920
we might metabolise that
pharmaceutical in our liver,

856
00:51:28,920 --> 00:51:32,840
and then what we'll do is we'll
excrete either in our urine

857
00:51:32,840 --> 00:51:36,560
or our poo, and that will go down
the sewage works.

858
00:51:36,560 --> 00:51:40,280
If you take something like the
anti-epileptic drugs we use,

859
00:51:40,280 --> 00:51:43,240
they're not removed hardly at all
by the way sewage treatments work.

860
00:51:43,240 --> 00:51:47,280
So what sorts of drugs
are you looking for?

861
00:51:47,280 --> 00:51:48,800
And what do you find?

862
00:51:48,800 --> 00:51:52,840
They include things like
antibiotics, anti-depressants,

863
00:51:52,840 --> 00:51:56,480
things used for diabetes,
things for headaches,

864
00:51:56,480 --> 00:51:59,880
anti-inflammatory drugs.
So a real mixture.

865
00:51:59,880 --> 00:52:03,400
You just don't think about
it because you take it,

866
00:52:03,400 --> 00:52:05,560
you think it's metabolised
and it's gone away.

867
00:52:05,560 --> 00:52:07,120
It hasn't gone away,

868
00:52:07,120 --> 00:52:10,680
and it's ending up in the Thames
and elsewhere,

869
00:52:10,680 --> 00:52:13,240
affecting the wildlife there.

870
00:52:13,240 --> 00:52:15,680
So there's some really cool
data from the States

871
00:52:15,680 --> 00:52:20,200
where in the laboratory they added
anti-depressants to a tank.

872
00:52:20,200 --> 00:52:23,360
The tank contained a female
and a male fish, and they found

873
00:52:23,360 --> 00:52:26,280
that they didn't reproduce
like they would normally.

874
00:52:26,280 --> 00:52:28,120
Now, if that's happening in
the river,

875
00:52:28,120 --> 00:52:30,960
that could be really important
in terms of the survival

876
00:52:30,960 --> 00:52:32,160
of the fish populations.

877
00:52:32,160 --> 00:52:36,680
I find it almost unbelievable
that this is a hidden problem

878
00:52:36,680 --> 00:52:40,480
that we're only now just
beginning to cotton onto.

879
00:52:44,880 --> 00:52:47,440
Alistair's analysis of the
Thames samples

880
00:52:47,440 --> 00:52:49,560
reveals some startling results.

881
00:52:50,640 --> 00:52:53,920
What was the top hit?
The top one was a drug used

882
00:52:53,920 --> 00:52:56,120
for diabetes called Metformin.

883
00:52:56,120 --> 00:53:00,280
We saw a concentration of
290 nanograms per litre,

884
00:53:00,280 --> 00:53:05,680
and that works out at about
220 pills of Metformin.

885
00:53:05,680 --> 00:53:09,320
So here we have 220 tablets

886
00:53:09,320 --> 00:53:11,560
and they're flowing under
the bridge...

887
00:53:13,680 --> 00:53:16,440
..at Hampton Court every hour. Yep.

888
00:53:21,560 --> 00:53:26,400
So every day there'll be over 5,000
tablets going under that bridge

889
00:53:26,400 --> 00:53:29,120
and then out through the estuary
into the ocean.

890
00:53:29,120 --> 00:53:31,680
That just seems almost unbelievable.

891
00:53:33,920 --> 00:53:38,000
I would say to people watching this,
if you have unused medicines,

892
00:53:38,000 --> 00:53:39,560
don't throw them down the toilet.

893
00:53:39,560 --> 00:53:40,880
And that's what happens a lot.

894
00:53:40,880 --> 00:53:43,560
People just empty...
Take it back to your pharmacy.

895
00:53:43,560 --> 00:53:46,280
The pharmacist will take
those unused medicines

896
00:53:46,280 --> 00:53:48,800
and they will ensure they're
disposed of properly.

897
00:53:50,920 --> 00:53:54,280
If we're not careful,
pharmaceuticals could join plastics

898
00:53:54,280 --> 00:53:59,200
and industrial chemicals as major
pollutants harming marine wildlife.

899
00:54:02,160 --> 00:54:06,440
Human-made pollution is directly
impacting individual creatures

900
00:54:06,440 --> 00:54:11,680
in the sea, but our heavy footprint
is also posing a worldwide challenge

901
00:54:11,680 --> 00:54:13,720
to the whole ocean ecosystem.

902
00:54:18,560 --> 00:54:21,040
Increased carbon dioxide
in the atmosphere

903
00:54:21,040 --> 00:54:22,680
is heating up planet Earth.

904
00:54:26,120 --> 00:54:28,200
Since the Industrial Revolution,

905
00:54:28,200 --> 00:54:30,920
the world has warmed
by one degree Celsius.

906
00:54:32,480 --> 00:54:36,600
The UN has just published its most
comprehensive ever report

907
00:54:36,600 --> 00:54:41,160
on the threat that climate
change poses to our oceans.

908
00:54:41,160 --> 00:54:44,200
If we warm the Earth by just
one degree more,

909
00:54:44,200 --> 00:54:46,960
the consequences will be
devastating.

910
00:54:51,520 --> 00:54:54,360
I'm investigating the impact
of this warming world

911
00:54:54,360 --> 00:54:56,520
from here in the North Sea.

912
00:54:56,520 --> 00:54:59,560
Its waters have warmed twice
as much as the global ocean

913
00:54:59,560 --> 00:55:01,120
in the past 50 years.

914
00:55:03,200 --> 00:55:05,400
Whatever's happening here
can give us clues

915
00:55:05,400 --> 00:55:08,360
as to how the rest of the planet's
oceans might be affected.

916
00:55:12,160 --> 00:55:14,560
One of those impacts
is that a warmer world

917
00:55:14,560 --> 00:55:16,920
could drive more extreme weather.

918
00:55:18,720 --> 00:55:21,760
The wind's going to pick up.
It's just starting to rain now,

919
00:55:21,760 --> 00:55:26,640
so I think the North Sea has been
kind to us for all of...12 hours,

920
00:55:26,640 --> 00:55:29,520
and it is about to regain
its normal character.

921
00:55:29,520 --> 00:55:32,560
And I think the weather could be
quite enthusiastic this evening.

922
00:55:32,560 --> 00:55:34,600
WAVES CRASH

923
00:55:34,600 --> 00:55:38,400
The North Sea is notorious
for its storms.

924
00:55:39,680 --> 00:55:41,520
The season begins in autumn,

925
00:55:41,520 --> 00:55:45,520
after the ocean has basked
in a long summer of sunshine.

926
00:55:48,800 --> 00:55:51,720
The energy on Earth comes in
from the sun,

927
00:55:51,720 --> 00:55:54,000
and then it travels through
the Earth's system,

928
00:55:54,000 --> 00:55:55,800
through the ocean
and the atmosphere,

929
00:55:55,800 --> 00:55:58,280
and eventually,
it gets radiated away into space.

930
00:55:58,280 --> 00:56:00,920
So there's a flow in and a flow out.

931
00:56:00,920 --> 00:56:04,280
And the problem of the
greenhouse gases like carbon dioxide

932
00:56:04,280 --> 00:56:06,920
is that they slow down the flow out.

933
00:56:06,920 --> 00:56:09,720
So more energy is coming in
than is leaving.

934
00:56:09,720 --> 00:56:11,360
That's where global warming
comes from.

935
00:56:11,360 --> 00:56:14,920
It's that additional energy
that we're accumulating every year.

936
00:56:14,920 --> 00:56:18,200
And the next question is,
where does it go?

937
00:56:18,200 --> 00:56:21,200
And the answer,
and we can measure this,

938
00:56:21,200 --> 00:56:24,120
is that since 1970,
93% of that additional energy

939
00:56:24,120 --> 00:56:26,520
has ended up in our oceans.

940
00:56:33,480 --> 00:56:36,480
One of the predictions for
a warming world is that hurricanes,

941
00:56:36,480 --> 00:56:39,160
because the ocean is warmer,
they'll have more fuel,

942
00:56:39,160 --> 00:56:41,200
and so they'll be more intense.

943
00:56:41,200 --> 00:56:42,920
WIND GUSTS

944
00:56:42,920 --> 00:56:49,120
A large hurricane can expend as much
energy as 10,000 nuclear bombs.

945
00:56:50,800 --> 00:56:54,200
And a hotter world
will likely increase their power.

946
00:57:01,360 --> 00:57:05,040
As night falls,
the windstorm sweeps through.

947
00:57:05,040 --> 00:57:10,080
PhD student Tim de Groot is worried
that his sampling is at risk.

948
00:57:10,080 --> 00:57:13,440
We just talked with the crew. Like,
they are in charge of the safety.

949
00:57:13,440 --> 00:57:17,240
If they think it's unsafe enough,
then we won't do it.

950
00:57:17,240 --> 00:57:19,800
In my opinion, we can always do it.

951
00:57:29,760 --> 00:57:32,800
Up on the bridge,
the captain is monitoring the wind.

952
00:57:34,720 --> 00:57:36,240
We're encountering a storm now.

953
00:57:36,240 --> 00:57:38,360
On the Beaufort scale,
minimum force eight...

954
00:57:40,120 --> 00:57:44,680
..getting to nine
and sometimes peaking to ten.

955
00:57:44,680 --> 00:57:46,920
When you reach 12,
it's going to be a hurricane.

956
00:57:46,920 --> 00:57:49,720
We have slightly less,
but it's a rough storm.

957
00:57:53,600 --> 00:57:56,840
60mph gusts create a heavy swell...

958
00:57:59,880 --> 00:58:03,200
..so the crew is struggling
to bring the CTD in safely.

959
00:58:05,720 --> 00:58:07,560
And my kit is at risk, too.

960
00:58:08,600 --> 00:58:11,000
I have this nightmare about my
science kit sliding

961
00:58:11,000 --> 00:58:14,080
all over the floor, you know, as the
ship rocks, things falling off

962
00:58:14,080 --> 00:58:15,920
and getting broken
and hitting things.

963
00:58:19,640 --> 00:58:21,840
CLANGING

964
00:58:21,840 --> 00:58:25,040
It's too much for us
to do the job safely,

965
00:58:25,040 --> 00:58:28,360
so we cancelled all the operations
for the night.

966
00:58:31,080 --> 00:58:35,760
The storm has deprived the team
of an important set of data.

967
00:58:35,760 --> 00:58:39,480
I'm hoping the waves haven't put
an end to my science plans as well.

968
00:58:41,000 --> 00:58:43,000
So I'm coming into
the lab space here.

969
00:58:45,360 --> 00:58:48,760
And...the waves haven't got to it.

970
00:58:48,760 --> 00:58:50,160
Everything is still there.

971
00:58:51,960 --> 00:58:53,800
And still secure.

972
00:58:53,800 --> 00:58:55,480
So I feel a lot better now.

973
00:59:09,280 --> 00:59:12,600
As the world warms
and sea levels rise,

974
00:59:12,600 --> 00:59:16,120
more powerful storms
will batter the British coast,

975
00:59:16,120 --> 00:59:18,240
bringing more floods with them.

976
00:59:18,240 --> 00:59:19,840
WAVES CRASH

977
00:59:21,240 --> 00:59:23,800
Scientists predict
that by the year 2050,

978
00:59:23,800 --> 00:59:28,520
once-a-century floods could
happen as often as once a year.

979
00:59:33,520 --> 00:59:37,720
Six days into the voyage, we've
arrived at a spot that reveals just

980
00:59:37,720 --> 00:59:42,000
how dramatically the North Sea's
coastline has changed in the past.

981
00:59:42,000 --> 00:59:44,800
It's a spot made familiar
by the shipping forecast.

982
00:59:46,800 --> 00:59:50,160
Dogger, south-west, four or five,
becoming cyclonic.

983
00:59:50,160 --> 00:59:53,360
Then west later,
seven to severe gale nine,

984
00:59:53,360 --> 00:59:55,360
perhaps storm ten later.

985
00:59:58,240 --> 01:00:01,480
Dogger Bank is 150 miles east
of Whitby,

986
01:00:01,480 --> 01:00:04,040
and the biggest sandbank
in the North Sea.

987
01:00:07,200 --> 01:00:10,600
I'm up on the ship's bridge
with Chief Officer Len Bliemer,

988
01:00:10,600 --> 01:00:12,800
to take a closer look.

989
01:00:12,800 --> 01:00:14,400
So that's our position
at the moment.

990
01:00:14,400 --> 01:00:16,960
You can see we are right on the edge
of the Dogger Bank.

991
01:00:16,960 --> 01:00:18,560
You can see the depths in metres.

992
01:00:18,560 --> 01:00:21,280
The Dogger Bank is, like,
15 to 25 metres.

993
01:00:21,280 --> 01:00:24,080
That's really shallow.
It's really shallow, yeah.

994
01:00:26,080 --> 01:00:28,320
Just 9,000 years ago,

995
01:00:28,320 --> 01:00:32,800
our ship couldn't even have sailed
above the Dogger Bank

996
01:00:32,800 --> 01:00:36,360
because this whole area
and everything around it

997
01:00:36,360 --> 01:00:37,640
would have been land.

998
01:00:39,880 --> 01:00:43,360
And this is a reconstruction
of the area at that time.

999
01:00:43,360 --> 01:00:45,440
And you can see Britain
on the left here,

1000
01:00:45,440 --> 01:00:47,680
and then, Norway and Europe
on the right.

1001
01:00:47,680 --> 01:00:51,440
And in between, instead of the
English Channel and the North Sea,

1002
01:00:51,440 --> 01:00:53,720
we can see there's
this great big plain here,

1003
01:00:53,720 --> 01:00:56,160
and this was Doggerland.

1004
01:00:56,160 --> 01:00:59,600
The thing I love about this map is
you can see that there were hills.

1005
01:00:59,600 --> 01:01:02,320
You can see the rivers
and this big lake in the middle.

1006
01:01:02,320 --> 01:01:05,480
Humans lived here.
We've got archaeological artefacts.

1007
01:01:05,480 --> 01:01:08,720
Fishermen have been dredging up
things like stone axes from

1008
01:01:08,720 --> 01:01:11,880
this area and there are bones
of animals that lived here.

1009
01:01:11,880 --> 01:01:15,240
We've got the evidence
that this was a real place.

1010
01:01:15,240 --> 01:01:16,880
But it's not here any more.

1011
01:01:16,880 --> 01:01:19,000
And to see what happened to it,

1012
01:01:19,000 --> 01:01:22,520
we just have to wind the maps
forward in time a little bit.

1013
01:01:22,520 --> 01:01:25,600
So this is now 10,000 years ago,

1014
01:01:25,600 --> 01:01:28,040
and you can see the big plain of
Doggerland is still here,

1015
01:01:28,040 --> 01:01:29,880
still looks like a place
you could visit,

1016
01:01:29,880 --> 01:01:33,320
but over here,
this is 9,000 years ago,

1017
01:01:33,320 --> 01:01:35,640
and now, this is the end
of the last ice age

1018
01:01:35,640 --> 01:01:37,600
and sea level is starting to rise.

1019
01:01:37,600 --> 01:01:41,200
And as it rises, it covers over
the lowest parts of Doggerland

1020
01:01:41,200 --> 01:01:43,440
and it keeps rising and keeps rising

1021
01:01:43,440 --> 01:01:47,280
so that there's only this little bit
left 8,200 years ago.

1022
01:01:47,280 --> 01:01:50,480
And then, by 7,000 years,
Doggerland has gone.

1023
01:01:50,480 --> 01:01:52,400
It's vanished underneath the sea.

1024
01:01:55,440 --> 01:01:57,240
The lost marshes of Doggerland

1025
01:01:57,240 --> 01:01:59,960
show just how dramatically
sea levels have changed

1026
01:01:59,960 --> 01:02:01,800
over the North Sea's history.

1027
01:02:04,400 --> 01:02:08,440
In just a few thousand years
at the end of the last ice age,

1028
01:02:08,440 --> 01:02:10,720
melting ice sheets and warmer oceans

1029
01:02:10,720 --> 01:02:14,560
made sea levels rise
by more than 30 metres.

1030
01:02:18,000 --> 01:02:22,480
Today, sea levels are rising faster
than at any time since then.

1031
01:02:22,480 --> 01:02:25,040
And this time, it's caused by us.

1032
01:02:27,880 --> 01:02:31,000
Three degrees of warming
by the year 2100

1033
01:02:31,000 --> 01:02:35,720
could see major world cities
like Miami, Shanghai and Osaka

1034
01:02:35,720 --> 01:02:37,520
engulfed by the sea.

1035
01:02:41,720 --> 01:02:44,360
At Wallasea Island,
near the mouth of the Thames,

1036
01:02:44,360 --> 01:02:46,520
just 50 miles from London,

1037
01:02:46,520 --> 01:02:49,120
an ambitious project
is working WITH nature

1038
01:02:49,120 --> 01:02:52,680
to develop a pioneering form
of flood defence.

1039
01:02:54,400 --> 01:02:58,920
I'm joining Jeff Kew, who oversaw
the development of the site.

1040
01:02:58,920 --> 01:03:01,760
Hi, Jeff. George, hello!
Welcome to Wallasea Island.

1041
01:03:01,760 --> 01:03:04,960
Nice to meet you. Thank you.
Now, how big an area is this?

1042
01:03:04,960 --> 01:03:07,160
Well, Wallasea Island,
it's the largest

1043
01:03:07,160 --> 01:03:09,680
coastal habitat restoration site
in Europe.

1044
01:03:11,800 --> 01:03:16,280
So we're standing on a sea wall
that was built in about 1500.

1045
01:03:16,280 --> 01:03:19,040
To this side, we have
the River Roach, which is tidal,

1046
01:03:19,040 --> 01:03:21,960
and on the other side,
we have Wallasea Island.

1047
01:03:21,960 --> 01:03:24,880
And that farmland, or it used to be
farmland, is a lot lower.

1048
01:03:24,880 --> 01:03:26,680
Yeah, it's lower than sea level.

1049
01:03:26,680 --> 01:03:29,840
So we're about a metre and a half
below high-tide level.

1050
01:03:29,840 --> 01:03:33,960
So we're now coming down
off the sea wall,

1051
01:03:33,960 --> 01:03:37,120
on to the sea side of the wall.

1052
01:03:37,120 --> 01:03:39,880
Now, this is a very simple
structure.

1053
01:03:39,880 --> 01:03:43,800
It's just an earth bank
with a concrete block face.

1054
01:03:43,800 --> 01:03:47,160
Yeah, a simple sea wall,
but designed on the assumption

1055
01:03:47,160 --> 01:03:49,800
that there would always be
salt marsh in front.

1056
01:03:49,800 --> 01:03:52,480
And what's the problem? Well, I can
see bits of the problem here.

1057
01:03:52,480 --> 01:03:54,000
Yeah... It's breaking up.

1058
01:03:54,000 --> 01:03:55,800
You can see the problem
very clearly here.

1059
01:03:55,800 --> 01:03:59,760
What's happened is the salt marsh in
front has been lost through erosion,

1060
01:03:59,760 --> 01:04:03,760
allowing the sea to attack
these blocks and erode the wall.

1061
01:04:03,760 --> 01:04:06,280
The problem is,
with rising sea levels,

1062
01:04:06,280 --> 01:04:09,800
this will happen extensively
over whole lengths of walls,

1063
01:04:09,800 --> 01:04:13,120
and then the whole thing
becomes unsustainable.

1064
01:04:16,720 --> 01:04:21,000
Jeff's ingenious solution to the
crumbling sea walls is to make use

1065
01:04:21,000 --> 01:04:24,520
of the miraculous properties
of the salt marsh itself.

1066
01:04:28,400 --> 01:04:32,880
Jeff's team breach sea walls to the
north and east of Wallasea Island

1067
01:04:32,880 --> 01:04:37,360
and transform 280 hectares
of arable fields

1068
01:04:37,360 --> 01:04:39,560
into salt marsh and mudflats.

1069
01:04:46,480 --> 01:04:50,120
He's agreed to show me an overview
of the work so far.

1070
01:04:55,200 --> 01:04:58,440
For us, seeing these images,
it's, um...it's fantastic,

1071
01:04:58,440 --> 01:05:01,720
cos we're achieving
exactly what we set out to do.

1072
01:05:05,800 --> 01:05:07,680
If we fly down here gently,

1073
01:05:07,680 --> 01:05:10,400
we're heading to
the northern breach.

1074
01:05:10,400 --> 01:05:13,520
So this is the breach
which takes the majority of water

1075
01:05:13,520 --> 01:05:16,320
in and out of the site each tide.

1076
01:05:16,320 --> 01:05:20,680
Now, every time the tide comes in,
it will drop silt.

1077
01:05:20,680 --> 01:05:25,240
All this shiny mud that you can see,
that's all new mud that's come in.

1078
01:05:25,240 --> 01:05:28,080
So this site has already accreted
since breaching.

1079
01:05:29,840 --> 01:05:34,600
This silt, carried in by the tide,
is transforming Wallasea.

1080
01:05:35,680 --> 01:05:39,840
Crucial to the whole habitat
is the salt marsh vegetation.

1081
01:05:42,200 --> 01:05:46,720
Well, Jeff, this, at first glance,
it doesn't look very interesting,

1082
01:05:46,720 --> 01:05:50,720
but actually, up close, there's lots
and lots of plants here.

1083
01:05:50,720 --> 01:05:54,760
Yeah, there's a great diversity of
salt marsh plants already growing.

1084
01:05:54,760 --> 01:05:57,600
What makes them so useful to us?

1085
01:05:57,600 --> 01:06:00,680
They provide quite a dense map
of stems,

1086
01:06:00,680 --> 01:06:04,280
and what these do is, when the sea
comes in, laden with silt,

1087
01:06:04,280 --> 01:06:08,560
the silt drops,
is trapped by the vegetation,

1088
01:06:08,560 --> 01:06:12,320
and then the ground just goes up
and up as this silt is caught.

1089
01:06:12,320 --> 01:06:14,880
And this enables the salt marsh

1090
01:06:14,880 --> 01:06:17,840
to physically go up in height
progressively.

1091
01:06:17,840 --> 01:06:20,400
And what we think,
with rising sea levels,

1092
01:06:20,400 --> 01:06:24,200
is that many of these marshes will
be able to just keep going up

1093
01:06:24,200 --> 01:06:26,800
and keep up with levels of
sea-level rise.

1094
01:06:26,800 --> 01:06:31,440
So it's a win-win. If we don't try
and fight the natural world,

1095
01:06:31,440 --> 01:06:33,440
it will help us in the end.

1096
01:06:33,440 --> 01:06:37,440
We need to provide space for nature
and habitats like this,

1097
01:06:37,440 --> 01:06:40,400
and use nature to help us.

1098
01:06:40,400 --> 01:06:41,880
BIRDSONG

1099
01:06:41,880 --> 01:06:44,520
Thanks to the rewilding
of Wallasea Island,

1100
01:06:44,520 --> 01:06:48,440
the reserve has become a major
new home for breeding birds.

1101
01:06:48,440 --> 01:06:50,000
BIRDSONG

1102
01:06:52,520 --> 01:06:56,760
Almost 150 pairs of avocets
live here year-round.

1103
01:06:56,760 --> 01:06:59,520
More than at any other site
in the UK.

1104
01:07:03,040 --> 01:07:06,600
The growing salt marsh is also
the best possible habitat

1105
01:07:06,600 --> 01:07:09,600
to combat rising
greenhouse emissions.

1106
01:07:09,600 --> 01:07:15,560
As it traps silt, it locks away
50 times more atmospheric carbon

1107
01:07:15,560 --> 01:07:17,880
than a forest of the same size.

1108
01:07:17,880 --> 01:07:20,880
Well, it's hard to believe
that what I'm looking at

1109
01:07:20,880 --> 01:07:24,120
was arable fields
only four years ago.

1110
01:07:24,120 --> 01:07:27,240
And it just goes to show,
we don't have to defend ourselves

1111
01:07:27,240 --> 01:07:31,400
against sea-level rise by using
enormous amounts of concrete.

1112
01:07:37,120 --> 01:07:40,440
Natural flood defences
like this could help fight

1113
01:07:40,440 --> 01:07:43,640
the sea-level rise we will face
in the coming century,

1114
01:07:43,640 --> 01:07:48,440
saving many coastal communities
in Britain and around the world.

1115
01:07:57,040 --> 01:08:00,320
The extra carbon dioxide in
the atmosphere won't just affect

1116
01:08:00,320 --> 01:08:03,360
the planet through climate change
and sea-level rise.

1117
01:08:03,360 --> 01:08:06,720
It has a dramatic effect
within the ocean, too.

1118
01:08:08,400 --> 01:08:11,440
My own area of research
investigates what's going on.

1119
01:08:13,400 --> 01:08:15,400
It's the study of ocean bubbles.

1120
01:08:16,680 --> 01:08:19,320
We've got these breaking waves on
the surface, and they are doing

1121
01:08:19,320 --> 01:08:22,160
something really interesting -
they're helping the ocean breathe.

1122
01:08:22,160 --> 01:08:25,320
So when a wave breaks, it takes
little pockets of the atmosphere

1123
01:08:25,320 --> 01:08:27,680
down underneath
the surface of the ocean.

1124
01:08:27,680 --> 01:08:30,120
And it's the big bubbles
and these breaking waves,

1125
01:08:30,120 --> 01:08:32,760
the ones that we can see,
are helping push carbon dioxide

1126
01:08:32,760 --> 01:08:34,600
from the atmosphere into the ocean.

1127
01:08:34,600 --> 01:08:36,040
WAVES CRASH

1128
01:08:37,280 --> 01:08:41,640
The ocean is actually taking
up something like 25%-30%

1129
01:08:41,640 --> 01:08:45,160
of all the extra carbon dioxide
that's going up into the atmosphere.

1130
01:08:47,400 --> 01:08:51,200
This natural carbon capture
sounds like good news,

1131
01:08:51,200 --> 01:08:52,920
but it comes at a price.

1132
01:08:54,520 --> 01:08:57,080
A price that threatens
the ocean ecosystems

1133
01:08:57,080 --> 01:08:59,480
more immediately
than a changing climate.

1134
01:09:01,040 --> 01:09:03,400
Ocean acidification.

1135
01:09:03,400 --> 01:09:06,080
I've got a tank of sea water here

1136
01:09:06,080 --> 01:09:09,600
and what I've got down here
is dry ice.

1137
01:09:09,600 --> 01:09:12,600
So this is solid carbon dioxide
that's frozen.

1138
01:09:12,600 --> 01:09:14,720
So I'm going to add it
to the sea water.

1139
01:09:20,400 --> 01:09:22,360
Ooh!
SHE LAUGHS

1140
01:09:22,360 --> 01:09:25,920
That is a lot of bubbling.
Loads of bubbles!

1141
01:09:27,200 --> 01:09:30,480
The solid carbon dioxide
is turning into a gas.

1142
01:09:30,480 --> 01:09:33,080
And as it bubbles through
the water here,

1143
01:09:33,080 --> 01:09:35,000
making all this lovely vapour,

1144
01:09:35,000 --> 01:09:37,600
some of it will be coming out
of the water,

1145
01:09:37,600 --> 01:09:41,840
but lots of it will be dissolving
in the water in the tank here.

1146
01:09:44,000 --> 01:09:48,440
So this is a pH metre that measures
how acid or alkaline the water is.

1147
01:09:48,440 --> 01:09:52,440
And as the carbon dioxide dissolves,

1148
01:09:52,440 --> 01:09:54,760
we can see the effects on the pH.

1149
01:09:57,080 --> 01:10:00,200
The ocean's pH should be 8.1,

1150
01:10:00,200 --> 01:10:02,240
but our sea water reading
is rapidly dropping.

1151
01:10:03,760 --> 01:10:06,800
This number going down
means that the water here

1152
01:10:06,800 --> 01:10:08,920
is becoming more and more acidic

1153
01:10:08,920 --> 01:10:11,920
as more and more carbon dioxide
dissolves into it.

1154
01:10:11,920 --> 01:10:15,000
Now, this is just a small tank,

1155
01:10:15,000 --> 01:10:18,320
but humanity is currently
conducting an experiment

1156
01:10:18,320 --> 01:10:21,360
that is very similar to this
on a global scale.

1157
01:10:21,360 --> 01:10:25,280
The oceans are massive,
but the amount of carbon dioxide

1158
01:10:25,280 --> 01:10:28,360
we're adding to them
is also gigantic.

1159
01:10:28,360 --> 01:10:32,280
And even though our oceans are big,
we can already measure this.

1160
01:10:32,280 --> 01:10:35,240
We know that humanity
has already changed the pH

1161
01:10:35,240 --> 01:10:37,240
of the entire global ocean.

1162
01:10:40,000 --> 01:10:42,400
The carbon dioxide we've emitted
into the atmosphere

1163
01:10:42,400 --> 01:10:45,000
has increased the ocean's acidity

1164
01:10:45,000 --> 01:10:48,360
by just a small fraction of
a single pH unit.

1165
01:10:50,600 --> 01:10:54,480
That doesn't sound like much,
but it's enough to radically alter

1166
01:10:54,480 --> 01:10:59,160
one of the most diverse ecosystems
on Earth - coral reefs.

1167
01:11:00,480 --> 01:11:04,200
Coral covers less than 1%
of the ocean floor,

1168
01:11:04,200 --> 01:11:08,680
but it supports over 25%
of the species in the sea.

1169
01:11:11,120 --> 01:11:14,280
The hard parts of corals
and the shells of shellfish

1170
01:11:14,280 --> 01:11:16,880
are built from a material called
calcium carbonate,

1171
01:11:16,880 --> 01:11:20,360
one that's particularly sensitive
to acid conditions.

1172
01:11:22,840 --> 01:11:25,640
How will these creatures cope
with a more acidic ocean?

1173
01:11:28,920 --> 01:11:31,720
To find out, I've got to wear some
protective clothing.

1174
01:11:43,720 --> 01:11:46,040
That was quite a dramatic reaction.

1175
01:11:46,040 --> 01:11:48,160
Now, what I just put into the tank
with these shells

1176
01:11:48,160 --> 01:11:51,560
was a really strong acid -
hydrochloric acid.

1177
01:11:51,560 --> 01:11:56,360
What's happening here is the acid is
actually dissolving away the shells.

1178
01:11:56,360 --> 01:11:59,080
The ocean is naturally alkaline,
and creatures like this

1179
01:11:59,080 --> 01:12:02,320
can build their shells quite easily
in an alkaline environment.

1180
01:12:02,320 --> 01:12:05,080
But once you add an acid,
what you do is

1181
01:12:05,080 --> 01:12:08,640
you take away the most important
building block they have -

1182
01:12:08,640 --> 01:12:10,320
calcium carbonate.

1183
01:12:10,320 --> 01:12:13,320
So it becomes harder for them to
harvest it from their surroundings

1184
01:12:13,320 --> 01:12:14,920
and build into their shells.

1185
01:12:21,880 --> 01:12:24,720
I left my shells in their acid bath
for four hours

1186
01:12:24,720 --> 01:12:26,920
and then they've been sitting
in fresh water for a day,

1187
01:12:26,920 --> 01:12:29,760
and just look at
what's happened to them.

1188
01:12:29,760 --> 01:12:33,560
That beautiful conch shell has
almost been entirely eaten away.

1189
01:12:33,560 --> 01:12:36,120
And this is extreme,
but it does highlight the point

1190
01:12:36,120 --> 01:12:40,080
that for creatures that build
their home from calcium carbonate,

1191
01:12:40,080 --> 01:12:43,560
it really matters how acid
or alkaline their environment is.

1192
01:12:43,560 --> 01:12:46,760
And actually, even a small shift
could make a really big difference.

1193
01:12:49,400 --> 01:12:51,360
This is an extreme example,

1194
01:12:51,360 --> 01:12:54,640
but our experiment demonstrates
the vulnerability of shells

1195
01:12:54,640 --> 01:12:56,360
to a more acidic ocean.

1196
01:12:58,240 --> 01:13:02,120
Some waters off North America's
west coast are so acidic

1197
01:13:02,120 --> 01:13:06,080
that they can dissolve the shells
of sea snails called pteropods.

1198
01:13:09,480 --> 01:13:14,000
In 2016 and 2017,
ocean acidification contributed

1199
01:13:14,000 --> 01:13:17,440
to the major bleaching events
on the Great Barrier Reef.

1200
01:13:17,440 --> 01:13:20,440
Bleaching is when coral ejects
the colourful algae

1201
01:13:20,440 --> 01:13:22,120
that keep the coral alive.

1202
01:13:23,440 --> 01:13:26,960
And scientists fear that all
coral reefs could be lost

1203
01:13:26,960 --> 01:13:29,240
by the end of the century.

1204
01:13:33,280 --> 01:13:35,400
It's already too late to reverse

1205
01:13:35,400 --> 01:13:38,320
the ocean acidification
we've caused so far.

1206
01:13:39,680 --> 01:13:42,200
If our carbon emissions continue
unchecked,

1207
01:13:42,200 --> 01:13:45,400
then the pace at which
our entire planet warms

1208
01:13:45,400 --> 01:13:48,000
also threatens to escape
our control.

1209
01:13:49,480 --> 01:13:51,880
Carbon dioxide isn't
the only greenhouse gas.

1210
01:13:51,880 --> 01:13:54,160
Next on the list is methane.

1211
01:13:54,160 --> 01:13:58,120
Methane is currently contributing
about a fifth to global warming.

1212
01:13:59,440 --> 01:14:02,640
In the final leg of
our North Sea health check,

1213
01:14:02,640 --> 01:14:05,320
we're 200 miles north-west
of the Dutch coast.

1214
01:14:08,520 --> 01:14:10,840
The Pelagia's chief scientist,
Helge, and his team

1215
01:14:10,840 --> 01:14:13,600
are conducting
an important experiment.

1216
01:14:13,600 --> 01:14:17,080
They're searching for a methane seep
at the bottom of the North Sea.

1217
01:14:18,960 --> 01:14:21,800
Methane is an extremely potent
greenhouse gas.

1218
01:14:21,800 --> 01:14:24,160
It's about 30 times
more powerful than CO2.

1219
01:14:26,360 --> 01:14:29,960
Methane has a more complex molecular
structure than carbon dioxide,

1220
01:14:29,960 --> 01:14:31,960
and it traps more heat from the sun.

1221
01:14:31,960 --> 01:14:36,400
If a large amount of sea floor
methane escapes to the atmosphere,

1222
01:14:36,400 --> 01:14:38,760
then the warming effect
could be dramatic.

1223
01:14:43,280 --> 01:14:47,720
In the 1980s, scientists discovered
a form of methane ice

1224
01:14:47,720 --> 01:14:49,800
called methane hydrate,

1225
01:14:49,800 --> 01:14:52,720
that forms naturally at the bottom
of the ocean.

1226
01:14:52,720 --> 01:14:55,160
These images show
its crystal structure.

1227
01:14:56,680 --> 01:15:01,040
Scientists estimate that more
than 1,000 trillion cubic metres

1228
01:15:01,040 --> 01:15:04,400
of methane ice is frozen away
in ocean sediments.

1229
01:15:06,400 --> 01:15:09,680
That's more carbon than in all
the world's oil and gas

1230
01:15:09,680 --> 01:15:11,080
reserves combined.

1231
01:15:12,560 --> 01:15:16,080
There's this picture where in the
Arctic, sort of locked away in cold

1232
01:15:16,080 --> 01:15:20,080
places, there is this huge store of
methane and it's just sitting there.

1233
01:15:20,080 --> 01:15:23,680
Yeah, if the ocean warms up,
then indeed more methane is coming

1234
01:15:23,680 --> 01:15:27,680
and then we have a positive feedback
loop, so the warmer it gets,

1235
01:15:27,680 --> 01:15:30,320
the more methane comes,
thus the warmer it gets.

1236
01:15:34,280 --> 01:15:37,560
Helge's trying to discover how much
methane the gas seeps can

1237
01:15:37,560 --> 01:15:38,960
deliver to the atmosphere.

1238
01:15:40,760 --> 01:15:44,480
So the team use the ship's sonar to
search for spots where they believe

1239
01:15:44,480 --> 01:15:48,680
bubbles are leaking from a peat bog
buried beneath flooded Doggerland.

1240
01:15:52,400 --> 01:15:55,360
On the map here, we've got the place
where you last saw it. Exactly.

1241
01:15:55,360 --> 01:15:57,480
We're just coming up to it.

1242
01:15:57,480 --> 01:16:00,680
OK, and now we are seeing it.
Oh, is that it? There it is.

1243
01:16:00,680 --> 01:16:02,320
There it is. It is coming.

1244
01:16:02,320 --> 01:16:05,800
You can see here
on the left as well...

1245
01:16:05,800 --> 01:16:08,160
That's a very strong reflection,
isn't it?

1246
01:16:08,160 --> 01:16:09,320
It is, it's very nice.

1247
01:16:10,520 --> 01:16:13,880
Now we've found the seep,
I can deploy my own bubble camera.

1248
01:16:15,800 --> 01:16:18,960
I'm hoping I can help Helge's
research by measuring how big

1249
01:16:18,960 --> 01:16:20,680
the bubbles are.

1250
01:16:20,680 --> 01:16:23,440
Measuring bubbles is what
I do in my professional life.

1251
01:16:24,600 --> 01:16:26,200
This is quite a special camera.

1252
01:16:26,200 --> 01:16:30,320
There are flashes that only
last for 20 millionths of a second.

1253
01:16:30,320 --> 01:16:33,240
It lights up a very precise
part of the ocean

1254
01:16:33,240 --> 01:16:35,800
and it can see all the bubbles,
just at that moment.

1255
01:16:48,960 --> 01:16:52,480
us, so we have a relatively high
chance that the bubbles will

1256
01:16:52,480 --> 01:16:54,160
come to the surface.

1257
01:16:57,840 --> 01:17:00,920
If we're in the correct spot,
my camera will give me

1258
01:17:00,920 --> 01:17:05,680
15 chances every second
to image the methane bubbles,

1259
01:17:05,680 --> 01:17:07,440
allowing me to measure their size.

1260
01:17:10,360 --> 01:17:12,960
We're back on board,
so it's all right. We're happy!

1261
01:17:12,960 --> 01:17:16,160
Now we've just got to see
what data's on it.

1262
01:17:16,160 --> 01:17:19,720
My pictures reveal the individual
methane bubbles climbing

1263
01:17:19,720 --> 01:17:21,080
through the water column.

1264
01:17:23,160 --> 01:17:26,400
Bigger bubbles float all
the way to the sea's surface

1265
01:17:26,400 --> 01:17:28,680
and deliver their methane
to the atmosphere.

1266
01:17:30,240 --> 01:17:33,800
But there are other bubbles that
dissolve into the sea before

1267
01:17:33,800 --> 01:17:35,120
they can make it to the top.

1268
01:17:36,840 --> 01:17:41,000
Can anything in the sea water
prevent this dissolved methane

1269
01:17:41,000 --> 01:17:44,600
from reaching the atmosphere
and accelerating global heating?

1270
01:17:46,120 --> 01:17:49,800
To find out,
Helge lowers a pump into the water

1271
01:17:49,800 --> 01:17:54,000
and pushes 150 litres of sea water
through filter paper.

1272
01:17:57,120 --> 01:17:59,880
We want to study this,
specifically looking at microbes,

1273
01:17:59,880 --> 01:18:01,880
which are hovering in the water
column,

1274
01:18:01,880 --> 01:18:04,200
and while this methane
is bubbling through,

1275
01:18:04,200 --> 01:18:08,160
they're sitting there, waiting,
hungry and feeding on this methane.

1276
01:18:13,320 --> 01:18:17,280
You can light methane, so it burns,
so there's chemical energy in it.

1277
01:18:17,280 --> 01:18:20,600
There's some organisms that can also
make use of this chemical energy in

1278
01:18:20,600 --> 01:18:24,880
a very similar way as you and I are
for instance making use of sugar.

1279
01:18:26,800 --> 01:18:31,480
The team carefully remove layers of
filter paper from inside the pump.

1280
01:18:31,480 --> 01:18:36,560
Sitting on each piece are billions
of methane-eating bacteria.

1281
01:18:36,560 --> 01:18:40,920
So the big question is actually,
how effective are these microbes?

1282
01:18:40,920 --> 01:18:43,360
Do they really eat up all
the methane?

1283
01:18:43,360 --> 01:18:45,600
If not, how much is going
into the atmosphere?

1284
01:18:49,080 --> 01:18:54,080
The team launches the CTD rosette
to take sea water samples

1285
01:18:54,080 --> 01:18:55,960
at five-metre intervals,

1286
01:18:55,960 --> 01:18:59,160
starting 30 metres down,
at the origin of the leak.

1287
01:19:00,440 --> 01:19:03,000
It then takes samples in the middle
of the water column,

1288
01:19:03,000 --> 01:19:05,280
and finally, at the surface.

1289
01:19:11,400 --> 01:19:14,600
So we know how much methane
is at the bottom layer, how much

1290
01:19:14,600 --> 01:19:18,280
methane is at the top layer, and how
much methane is in between of this.

1291
01:19:18,280 --> 01:19:21,240
And with these concentration
profiles, you can then model

1292
01:19:21,240 --> 01:19:25,360
how much methane is making its way
up into the atmosphere.

1293
01:19:25,360 --> 01:19:27,640
So what do Helge's results reveal?

1294
01:19:28,760 --> 01:19:30,640
We know that they are quite
effective

1295
01:19:30,640 --> 01:19:33,880
because we know a lot of methane is
being produced in ocean sediments,

1296
01:19:33,880 --> 01:19:37,240
but only relatively little is making
its way up into the atmosphere.

1297
01:19:39,240 --> 01:19:43,400
Helge and his colleagues have found
that ocean microbes consume

1298
01:19:43,400 --> 01:19:47,480
more than 90% of the methane that
has dissolved into the sea water.

1299
01:19:50,680 --> 01:19:53,520
His team will spend the coming
months analysing how that

1300
01:19:53,520 --> 01:19:56,240
figure can change with varying
ocean conditions.

1301
01:19:58,800 --> 01:20:02,200
Most importantly,
as the climate continues to warm,

1302
01:20:02,200 --> 01:20:05,000
will these bacteria still do
such a good job?

1303
01:20:07,600 --> 01:20:11,560
We could have a very, very gradual
change and then these methane-eating

1304
01:20:11,560 --> 01:20:14,600
microbes I think have a very good
chance of multiplying

1305
01:20:14,600 --> 01:20:17,440
and then basically taking care
of the problem. So they can keep up.

1306
01:20:17,440 --> 01:20:20,080
Exactly. As long as it only comes
out slowly, they can keep up.

1307
01:20:20,080 --> 01:20:21,280
Exactly.

1308
01:20:21,280 --> 01:20:25,760
But there is also quite some concern
that things may go rapidly,

1309
01:20:25,760 --> 01:20:27,280
at least in certain areas,

1310
01:20:27,280 --> 01:20:30,800
specifically in regions
like the East Siberian Shelf.

1311
01:20:30,800 --> 01:20:34,080
All of a sudden, the increase is
becoming quite tremendous,

1312
01:20:34,080 --> 01:20:37,560
and then you may also have the
situation where the methane-eating

1313
01:20:37,560 --> 01:20:39,120
microbes cannot keep up.

1314
01:20:39,120 --> 01:20:42,680
So if we warm everything too
quickly, and the methane gas escapes

1315
01:20:42,680 --> 01:20:45,040
too quickly,
the bacteria don't stand a chance

1316
01:20:45,040 --> 01:20:47,840
and it will reach the atmosphere.
Yeah. Yeah, exactly.

1317
01:20:49,800 --> 01:20:53,720
Helge's research is an important new
contribution to climate science,

1318
01:20:53,720 --> 01:20:57,480
and it matters because a sudden
runaway release of methane

1319
01:20:57,480 --> 01:20:59,200
could lead to a much hotter world.

1320
01:21:03,960 --> 01:21:07,200
This possibility is just
one of the reasons that the

1321
01:21:07,200 --> 01:21:11,440
United Nations wants to limit future
warming to half a degree Celsius.

1322
01:21:20,200 --> 01:21:22,200
After two weeks on board
the Pelagia,

1323
01:21:22,200 --> 01:21:23,840
our ocean autopsy is complete.

1324
01:21:25,960 --> 01:21:29,160
I've seen first-hand
the impact our actions are having

1325
01:21:29,160 --> 01:21:32,240
in the waters off our own shores.

1326
01:21:32,240 --> 01:21:35,120
But right now, I can't wait to
get my feet back onto dry land.

1327
01:21:43,360 --> 01:21:46,120
I've returned to Holland to find out

1328
01:21:46,120 --> 01:21:49,320
what Helen's learned from her
time at sea.

1329
01:21:49,320 --> 01:21:52,160
Well, I just got off the ferry
from the mainland over in Texel

1330
01:21:52,160 --> 01:21:55,920
and I'm just heading to meet Helen.

1331
01:21:55,920 --> 01:21:58,760
I'm really keen to find out how
she's got on.

1332
01:21:59,800 --> 01:22:02,440
I have to say, two weeks on a boat
in the North Sea is not

1333
01:22:02,440 --> 01:22:06,480
something I'd be queueing up to do!

1334
01:22:09,240 --> 01:22:10,480
And there she is.

1335
01:22:11,920 --> 01:22:13,480
The Pelagia.

1336
01:22:20,640 --> 01:22:22,920
Helen! Hello.

1337
01:22:22,920 --> 01:22:25,200
How are you doing?
How have you been? How was it?

1338
01:22:25,200 --> 01:22:28,720
It was, you know, bumpy in places,
but mostly... Bumpy in places?

1339
01:22:28,720 --> 01:22:31,280
I'm not a natural sailor,
I have to say.

1340
01:22:31,280 --> 01:22:33,400
Well, that's when it gets fun,
right?

1341
01:22:33,400 --> 01:22:35,560
Once the bumps start coming along,
that's

1342
01:22:35,560 --> 01:22:38,240
when you're really living at sea!
Well, let's have a debrief.

1343
01:22:40,680 --> 01:22:44,080
The last two weeks,
you've seen at first-hand just what

1344
01:22:44,080 --> 01:22:46,520
sort of impact we're having
out there.

1345
01:22:46,520 --> 01:22:49,640
I've not been out in the North Sea
before. I've mostly been out in the

1346
01:22:49,640 --> 01:22:51,800
open ocean.
And the biggest thing I noticed,

1347
01:22:51,800 --> 01:22:54,640
it's not just that it's changing,
cos that's a natural thing,

1348
01:22:54,640 --> 01:22:57,200
it's that it's changing faster than
the system can keep up.

1349
01:22:57,200 --> 01:23:01,440
I'm just beginning to get
a grip on how much stuff gets

1350
01:23:01,440 --> 01:23:04,840
washed into the sea.
It seems incredible to me that PCBs,

1351
01:23:04,840 --> 01:23:07,720
which were an entirely man-made
chemical group,

1352
01:23:07,720 --> 01:23:10,640
were banned 40, 50 years ago,

1353
01:23:10,640 --> 01:23:15,200
but they're still having their
effects as they magnify through the

1354
01:23:15,200 --> 01:23:17,840
food chain. And when I dissected the

1355
01:23:17,840 --> 01:23:22,880
porpoise, I did get a very strong
sense of this being a warning

1356
01:23:22,880 --> 01:23:28,400
actually, to say to us, "Guys,
can you stop doing this, please?"

1357
01:23:28,400 --> 01:23:32,920
I think that we're getting close
to too many things

1358
01:23:32,920 --> 01:23:34,480
changing at once cos the problem is,

1359
01:23:34,480 --> 01:23:37,200
the things that are stressing
the life, it's not just one thing,

1360
01:23:37,200 --> 01:23:40,440
it's not just plastics or just,
you know, pollution,

1361
01:23:40,440 --> 01:23:42,200
or just the temperature change.

1362
01:23:42,200 --> 01:23:44,080
They're getting
knocked from all sides.

1363
01:23:44,080 --> 01:23:45,880
There must be a different way.

1364
01:23:45,880 --> 01:23:49,680
But I think everybody would agree
the oceans have been pushed too far.

1365
01:23:52,000 --> 01:23:55,160
This is why research ships like the
Pelagia are so important because

1366
01:23:55,160 --> 01:23:59,040
they let us go and find things out,
and the more we understand,

1367
01:23:59,040 --> 01:24:01,520
the more we can be really sure that
we're making better

1368
01:24:01,520 --> 01:24:02,840
decisions in the future.

1369
01:24:02,840 --> 01:24:05,720
That's the thing that keeps me
at least a little bit optimistic

1370
01:24:05,720 --> 01:24:10,120
is that actually now we're starting
to have enough knowledge to

1371
01:24:10,120 --> 01:24:14,280
really understand. And we need to
take those hard choices...

1372
01:24:14,280 --> 01:24:15,760
..make those hard choices now.

1373
01:24:18,400 --> 01:24:22,880
So what choices do
we need to make to protect our seas?

1374
01:24:22,880 --> 01:24:27,080
Can we safeguard marine ecosystems
by ending our throwaway culture?

1375
01:24:28,480 --> 01:24:31,320
Can we ensure that any new
toxic chemicals

1376
01:24:31,320 --> 01:24:34,880
we invent will not persist through
the ocean food chain?

1377
01:24:37,120 --> 01:24:39,680
And can we prevent those
we've already made

1378
01:24:39,680 --> 01:24:42,040
from finding their way into the sea?

1379
01:24:45,120 --> 01:24:48,920
Can we limit global carbon
emissions to give the oceans

1380
01:24:48,920 --> 01:24:51,760
a chance of recovering
from their current state?

1381
01:24:53,360 --> 01:24:57,200
These are massive challenges,
and whether we can make them

1382
01:24:57,200 --> 01:24:58,960
is uncertain.

1383
01:25:00,640 --> 01:25:03,000
But there are positive signs.

1384
01:25:06,320 --> 01:25:07,840
And to see this for ourselves,

1385
01:25:07,840 --> 01:25:11,160
we're taking one last trip
off our own coast.

1386
01:25:19,280 --> 01:25:22,560
We're on our way to a site where
human infrastructure

1387
01:25:22,560 --> 01:25:25,920
and wildlife successfully
exist side by side.

1388
01:25:31,800 --> 01:25:36,120
And the sea is very calm, which is
good, cos we're going out into it.

1389
01:25:36,120 --> 01:25:39,720
It's very good for me.
Just a few miles that way.

1390
01:25:39,720 --> 01:25:42,800
You're not...
You're not a keen seaman! No!

1391
01:25:44,800 --> 01:25:47,560
We're sailing out to the
Scroby Sands Wind Farm,

1392
01:25:47,560 --> 01:25:49,480
just a few miles
off the Norfolk coast.

1393
01:25:52,040 --> 01:25:54,640
Wind farms have helped the UK
to reduce its carbon

1394
01:25:54,640 --> 01:25:58,880
footprint by almost 40% since 1990,

1395
01:25:58,880 --> 01:26:01,720
and they now produce
one fifth of Britain's electricity.

1396
01:26:03,720 --> 01:26:07,520
The aim is to raise that
to a third by 2030,

1397
01:26:07,520 --> 01:26:11,280
but that will require
the erection of 5,000 new turbines.

1398
01:26:14,640 --> 01:26:17,400
We've seen that the noise
produced by hammering turbines

1399
01:26:17,400 --> 01:26:20,800
into the sea bed is bad
news for marine life.

1400
01:26:20,800 --> 01:26:23,640
So the offshore wind industry is
under pressure to do

1401
01:26:23,640 --> 01:26:25,200
things in a better way.

1402
01:26:25,200 --> 01:26:28,040
It's one of those things where
knowledge is the thing you need.

1403
01:26:28,040 --> 01:26:31,760
There are ways now to build wind
turbines that make less noise.

1404
01:26:31,760 --> 01:26:33,640
You can put shielding
around the outside

1405
01:26:33,640 --> 01:26:36,360
so the noise doesn't get out,
so if you get them right, you can

1406
01:26:36,360 --> 01:26:39,920
perhaps put your wind
farm in the best place for it.

1407
01:26:39,920 --> 01:26:42,960
You can choose a place where it can
have benefits on the local ecology.

1408
01:26:42,960 --> 01:26:46,840
So we've got some video here
from right underneath one of these

1409
01:26:46,840 --> 01:26:50,880
wind turbines, and there's all
kinds of stuff down there. Anemone.

1410
01:26:50,880 --> 01:26:54,800
Anemones and barnacles, all
kinds of shells. Crab coming there.

1411
01:26:54,800 --> 01:27:00,400
So the actual structure of the wind
turbine provides a home for animals.

1412
01:27:00,400 --> 01:27:03,600
People have called them
an artificial reef.

1413
01:27:03,600 --> 01:27:06,000
On what use to be a sandy
bottom here,

1414
01:27:06,000 --> 01:27:09,000
there's quite a lot of concrete
and rocks and hard substrate

1415
01:27:09,000 --> 01:27:12,000
and that's where life like this
is really getting a grip.

1416
01:27:12,000 --> 01:27:14,640
There's more animals coming,
there's lots of fish there,

1417
01:27:14,640 --> 01:27:18,080
lots of animals, they'll be eating
the fish. You've got seals.

1418
01:27:18,080 --> 01:27:20,360
I saw at least three seals.

1419
01:27:20,360 --> 01:27:23,840
You can actually see on the video
here from a few years ago

1420
01:27:23,840 --> 01:27:28,240
and the red line is a single
seal that is going from one wind

1421
01:27:28,240 --> 01:27:31,520
turbine to the next to feed.
So it's basically working its way...

1422
01:27:31,520 --> 01:27:34,320
The seal knows this is a good
place for fish.

1423
01:27:34,320 --> 01:27:35,960
Yeah, it's feeding, doing very well,

1424
01:27:35,960 --> 01:27:39,000
and it knows exactly which
side its bread is buttered.

1425
01:27:40,880 --> 01:27:45,000
Globally, grey seals are endangered,
but here in the UK, their

1426
01:27:45,000 --> 01:27:48,560
numbers have grown hugely since seal
hunting was banned in the 1980s.

1427
01:27:50,800 --> 01:27:53,360
British and Irish waters are now

1428
01:27:53,360 --> 01:27:56,560
home to half of all the
grey seals on Earth.

1429
01:27:58,120 --> 01:28:01,160
There's no doubt the wind
turbines are changing the ecology,

1430
01:28:01,160 --> 01:28:03,800
but if they're changing it to make
it more biodiverse

1431
01:28:03,800 --> 01:28:06,720
and to bring back wildlife, then...
That's a good thing.

1432
01:28:06,720 --> 01:28:08,560
..you can see
that as a positive thing.

1433
01:28:08,560 --> 01:28:12,560
So when I see an offshore wind farm
now, I will actually think,

1434
01:28:12,560 --> 01:28:15,320
"Well, that could be a
little marine park."

1435
01:28:17,600 --> 01:28:21,680
Our autopsy of the North Sea has
shown that it's in crisis

1436
01:28:21,680 --> 01:28:25,520
and that the world's oceans
are headed in the same direction.

1437
01:28:27,000 --> 01:28:30,560
But it's also revealed that the
oceans themselves might hold

1438
01:28:30,560 --> 01:28:32,560
the key to their own survival.

1439
01:28:34,200 --> 01:28:36,120
We've seen just a few

1440
01:28:36,120 --> 01:28:40,160
of the functions that ocean life
can perform.

1441
01:28:40,160 --> 01:28:44,400
Ocean plankton produces more
than 50% of the oxygen we breathe.

1442
01:28:46,520 --> 01:28:50,840
Fungi and bacteria could break down
and digest plastic and methane.

1443
01:28:52,840 --> 01:28:55,880
Saltmarsh plants can fight
sea-level rise

1444
01:28:55,880 --> 01:28:57,640
and trap carbon at the same time.

1445
01:29:00,440 --> 01:29:03,960
Life in the ocean is
so diverse that it could fight back

1446
01:29:03,960 --> 01:29:07,040
against many of the challenges
that we're throwing at it.

1447
01:29:08,320 --> 01:29:10,600
But it's at a tipping point.

1448
01:29:10,600 --> 01:29:14,680
This is the crucial moment
to change our behaviour.

1449
01:29:14,680 --> 01:29:17,520
If we leave it any longer,
it will be too late.

1450
01:29:21,800 --> 01:29:26,200
The fact that that one is only under
a week old, it means it's got

1451
01:29:26,200 --> 01:29:30,800
lots to drink off its mum
and she must be reasonably healthy

1452
01:29:30,800 --> 01:29:34,480
and fit. It shows that wildlife
can be resilient,

1453
01:29:34,480 --> 01:29:36,680
if you give it a chance
and you look after it.

1454
01:29:36,680 --> 01:29:40,720
That's the one thing that actually
offers a huge amount of hope for me

1455
01:29:40,720 --> 01:29:45,160
is that if you give the natural
world a chance, it will come back.

1456
01:29:45,160 --> 01:29:47,440
And if we stop doing all
the things that we know

1457
01:29:47,440 --> 01:29:50,680
we shouldn't be doing, this is going
to happen all over the place.