Original subtitles

[Jeremy] Will the excavation of a centuries old

shipwreck reveal a secret smuggling operation?

There happens to be about twice as much money

on the vessel as should've been there.

[Jeremy] When an entire Russian ecosystem is obliterated,

could a strange ocean toxin be to blame?

Lots of marine wildlife starts washing up

on the beaches, dead or sick.

[Jeremy] And can satellites solve the 2021 mystery

of a submarine that plummets to deadly depths?

What force could tear a modern submarine into three pieces?

[Jeremy] The underwater realm is another dimension.

It's a physically hostile place,

where dreams of promise can sink into darkness.

I'm Jeremy Wade, and I'm searching the world

to bring you the most iconic and baffling

underwater mysteries known to science.

The vast majority of our ocean is unobserved,

unmapped and unexplored.

[Jeremy] It's a dangerous frontier that swallows evidence.

You have nowhere to run.

[Jeremy] Where unknown is normal and understanding is rare.

[eerie music playing]

The submarine is the ultimate weapon of modern warfare,

and right now, there are thought to be more than 500 manned subs

in the world's oceans, ready to launch into battle.

But when a sub with 53 crew disappears

without a trace during peace time, in 2021,

the international community is bewildered.

It quickly becomes a race against time to find

the missing vessel and rescue the crew before it's too late.

April 21st, 2021.

A breaking story hits the news.

A submarine with 53 crew members on board is missing.

Attack submarine KRI Nanggala 402 has disappeared

in waters around 51 nautical miles north of Bali.

Indonesian Navy officials say they lost contact

with the 200-foot long sub during a training exercise.

Its crew made contact to ask permission

to execute a dive,

and then, radio silence.

Where is the Nanggala?

[Rob] There's no war in this part of the world,

so it's unlikely that the submarine

would have been a victim of conflict.

What happened to the submarine?

[Jeremy] With the world watching,

a massive search and rescue operation gets underway.

A submarine has roughly three days of air.

If you still have power, you can possibly stretch it out

a bit longer, but the rule of thumb is,

"if things go wrong, lots of things go wrong."

[Jeremy] The Indonesian Navy deploys five aircraft

and over 20 ships,

and they make a worrying discovery.

A large oil slick near the Nanggala's

last known position.

[Michael] Oil on the sea surface is a very bad thing.

It means oil in a contained system got out.

If oil is leaking out of a submarine,

that usually means the pressure hull has been pierced.

[Jeremy] Does this mysterious oil slick mean the Nanggala

is in critical condition?

If so, how could the subs fixed steel hull

who'd been compromised?

It was constructed in Germany in the late 1970s.

Nanggala was an old submarine. She was due to be replaced.

Over its long service, the sub underwent several refits,

one as recently as 2012.

The integrity of the hull was flagged as a concern.

Submarines lives are not measured in years,

it's measured in hull years.

How many more dives it can do, and it can take.

And if a submarine reaches those number of dives,

you do not send that submarine out there.

Nanggala hadn't reached that point yet, but she wasn't far off it.

[Jeremy] The Nanggala is near the end of its career,

but the sub was still fit for purpose.

[Alexander] The Indonesians have a good track record

when it comes to submarines.

If they are unserviceable, they don't send it back in the water till they are.

[Jeremy] With the Nanggala missing for 24 hours,

the international community rallies to Indonesia's aid,

launching a large scale search.

After three days, hopes are diminishing for the survival of the crew.

Then, on April 24th, the Indonesian navy finds

an array of debris they think has come from the Nanggala.

Among the objects is a possible clue.

A part of the submarine that is associated

with the torpedo tubes.

[Michael] We know it was out on a training mission.

We know the training mission was in part for a torpedo practice.

[Jeremy] Is it possible that the Nanggala's explosive

weaponry is somehow to blame for its disappearance?

According to the navy, the Nanggala had requested

permission to dive to fire a torpedo

shortly before contact was lost.

[Lisa] The last communication with the Nanggala is at 4:00 a.m.

This is when the officer authorized the firing of the torpedo.

Is it possible that the firing of the torpedo has somehow

gone wrong, causing some sort of catastrophic explosion?

[Jeremy] If so, it's not the first time this has happened.

In 2000, Russian submarine K141, the Kursk,

is taking part in a large-scale naval exercise,

loaded with a full complement of combat weapons.

During preparations to fire one of their torpedoes,

fueled by hydrogen peroxide,

a failure occurs, causing an explosion.

[explosion]

The blast blows a large hole in the hull,

killing all but 23 of the 118 people on board.

[Jeremy] While the Nanggala's training exercise

was also using live torpedoes,

officials don't believe one went off.

[Lisa] During such a naval training exercise,

surely ships would have had hydrophones in the water,

yet no blast was detected at the time of the incident.

[explosion]

If there was an explosion, it should have been heard by these hydrophones.

It's not likely that a faulty weapon's explosion caused the blast,

in which case something else must have happened.

[Jeremy] Soon after the debris is found, a search and recovery vessel

surveys a possible target on the sea floor.

An ROV is sent down to investigate.

The images instantly confirm everyone's worst fears.

[Lisa] The Nanggala is found at a depth of 2,800 feet,

which is far deeper than its maximum safe depth.

There's no hope for the 53 crew on board.

[Jeremy] It's a tragic outcome for the submariners.

The only consolation for their loved ones now

is to figure out exactly what went wrong.

And soon, investigators discover a disturbing twist to the story.

The submarine has been ripped into three pieces.

What force could tear a modern submarine into three pieces?

In April 2021, the Indonesian submarine Nanggala

is found on the seabed.

It's hull ruptured and broken into three pieces.

Experts now suspect that the sub sank to depths

it wasn't built to withstand, causing a violent implosion.

Indonesian officials are determined to find

the cause of this catastrophe.

Was it a technical failure? Was it nature?

It's a mystery.

[Jeremy] There are limits to what the wreckage can reveal,

so investigators must turn elsewhere for clues.

Satellite data, taken around the time of the tragedy,

reveals the presence of a force under the ocean surface,

called "internal waves."

Right around the time of the tragedy,

NASA's aqua satellite captures a ripple in the Lombok strait.

Could this ripple be evidence for an internal

wave occurring at the exact same time?

[Jeremy] Internal waves occur where layers of water with different densities meet.

As currents move around the ocean,

these layers can collide with geographical features

on the sea floor, causing huge waves to form.

These invisible underwater waves can measure

a staggering 500 feet from peak to trough.

They are much, much bigger and much,

much slower than surface waves, but they disturb

the inside of the ocean as they travel outwards.

[Jeremy] And some say they're powerful enough to drag

a submarine to perilous depths.

They can travel for miles, and they can go at speeds of up to five knots.

You can't see very much evidence of them on the surface.

[Jeremy] But how could an internal wave destroy a submarine?

The submarine has one job, which is to stay at the right depth.

It's very easy to go sideways in the ocean,

but up and down is critical.

[Jeremy] In order to stay at a consistent depth,

a submarine will adjust its buoyancy

depending on the density of the surrounding water.

But if an internal wave envelops the vessel,

that density can change in an instant.

If the water becomes more dense, it can push the submarine up,

but if it's suddenly less dense, the submarine can plummet.

[Helen] That change of density could be enough to adjust

the submarine's buoyancy in a way that wasn't expected.

[Lisa] Without taking some kind of quick action to mitigate

the actions of the wave, a submarine could easily

be pushed below its safe operating depth.

[Jeremy] In June of 2021, the Indonesian government

abandons plans to salvage the wreckage.

They claim the risk and difficulty of raising it

from the sea floor is currently too high.

So we may need to wait a little longer to find out

what really happened to the Nanggala,

and if internal waves were the invisible cause of its destruction.

Perhaps the truth will be found, but only at the bottom of the sea.

[camera shutter clicking]

China, Russia and the US are spending big money

to better understand internal waves

and their potential impact on naval operations.

While this invisible phenomenon could be

responsible for the tragic loss of the Nanggala,

more evidence is needed to definitively say

what forced her to take such a deep and deadly dive.

[intense music playing]

When it comes to merchants of the high seas,

no one has been more successful

than the Dutch East India Company.

In the 1700s, the company was worth

an estimated $7.9 trillion in today's money.

A recently discovered shipwreck may finally reveal

a hidden side to the business,

in which sailors onboard the ships were smuggling silver

and playing the markets.

In 2005, a salvage team investigates the remains

of a Dutch merchant ship, 80 feet below the sea surface.

The Rooswijk was lost off the southern coast of England.

On a treacherous ten miles sand bar called the Goodwin Sands.

[Alexander] This ship disappeared.

It was supposed to be sailing out to the Dutch Hell Islands

in South East Asia, and it turns out it never got

further than the English channel.

[Jeremy] As they investigate the wreck,

salvagers uncover a hoard of unexpected riches.

It's found that the shipwreck has a cargo of silver,

which is obviously highly valuable.

[Jeremy] They find 1,000 silver bars

and around 36,000 silver dollars neatly stacked in chests.

These coins of the infamous Pieces of Eight,

so-called because they were worth eight Spanish reales each.

[Lisa] One coin is worth about $100 in today's money.

That means there's over $3 million worth.

The ship was carrying silver for basic trade purposes.

The Europeans wanted spices,

they wanted the porcelains, they wanted silks.

Where could you get them? The Far East.

[Jeremy] The salvaged silver from the Rooswijk

is handed over to Dutch authorities.

But in 2017, a groundbreaking Dutch

and English archaeological project

revisits the Rooswijk, in a bid to study

and preserve the wreck.

Using state-of-the-art equipment to survey the site,

divers make an unexpected discovery.

A different type of silver not previously detected,

and it's not neatly stacked in chests,

but scattered across the site.

[Beverly] What's unusual is it's actually found

in individual piles all over.

[Jeremy] This strange surplus silver doesn't belong

with the ship's cargo.

Does analysis of the coins suggest a secret unofficial

industry involving the Rooswijk crew?

Who were the men on board? Were they merchants, or were they smugglers?

[Jeremy] Archaeologists excavating a Dutch shipwreck

find vast amounts of silver coins scattered across

the surrounding seabed in bizarre clusters.

The loose piles of money indicate they were being

carried by individual sailors when the ship went down.

And there's something very strange about the coins themselves.

We find coins everywhere, and when we started

to prepare these out, we saw that they were also very different.

[Jeremy] These don't resemble the silver found

in the chest in 2005.

Bizarrely, many of them aren't even

from the same century as the Rooswijk.

These coins turned out not to be those silver reales.

[Beverly] Some of the coins that they find

are from the 17th century,

which is a full century before the ship takes sail.

[Jeremy] Even stranger, many of the coins

have holes drilled through them.

[Martijn] I'd think those holes were there to put on a string

and put it around your neck

or maybe sewed into your clothes

so nobody would see that you did have coins on board of the ship.

We had never seen that before.

We had never seen those coins, with those little holes.

[Jeremy] Official records show the Rooswijk should have been

carrying 300,000 Dutch guilders' worth of silver.

Now it's thought the ship was actually carrying double that amount.

There happens to be about twice as much money

on the vessel as should have been there.

[Jeremy] Why was there so much concealed silver on board,

and who was carrying it?

In 1740, the Rooswijk's crew are employees

of the Dutch East India Company, also known as the VOC.

Its business is global trade.

Compared to the world's wealthiest companies of today,

the VOC is still the biggest corporation ever to have existed.

[Helen] They owned these ships and shipping routes,

and the VOC were really very, very wealthy

and very, very powerful.

[Jeremy] Individuals on board are forbidden from bringing

their own silver to trade, but it would have been

very tempting, given the high demand

for the precious metal in the Dutch East Indies.

Silver was worth far more in the East Indies

than in the Netherlands.

In some places it's more valuable than others.

In the East Indies, it's 30 to 40% more valuable than in Europe.

[Jeremy] Anyone making the trip would be in a position

to play the market, buying low and selling high.

If you didn't get caught, and made it back

from the East Indies with your goods intact,

you could make a staggering fortune.

[Jeremy] The sheer amount of illegitimate coins

among the wreckage proves there were smugglers on board

who hoped to cash in big.

In 2018, archaeologists excavate artifacts

that unveil key details about the people on board.

Can any of these objects tell us who had secret plans

to play the silver market?

[Martijn] We have oil lamps on board,

we even found complete wine bottles, with the corks still on it.

There's personal items.

There is a nice writing set.

There are candles on board.

It's such a rare find to see one of these ships.

We hear about them in history,

but to actually see the tangible evidence.

[Jeremy] Although many are well preserved, some of the nearly

300-year-old items are harder to examine.

The team finds giant concretions,

lumps of artifacts fused together

over the centuries by sediment and iron rust.

Researchers believe they contain

more smuggled silver.

Can x-rays help the team look inside,

and uncover the truth about the Rooswijk's smugglers?

Using these technologies it could be possible to better

understand the distribution of the coins on the ship,

and by doing that, we can get a better sense

of who these people were and what their story was.

[Jeremy] The Rooswijk crew range from high ranking

officers to deck hands, and even soldiers.

Determining who was carrying the coins

and who wasn't seems like an impossible task.

Can new scientific techniques identify

these secret smugglers?

In 1740, Dutch trade ship, the Rooswijk,

sinks just one day into its journey.

The team now excavating the ship

finds human remains among the artifacts.

Evidence of the 237 who perished.

But it's the strange silver coins in the wreckage

that really get their attention,

and suggest a secret smuggling plot.

Who, among the crew, was on the take?

Some of the smuggled coins are bound up

in large concretions with other artifacts.

Breaking them apart could destroy them,

so the team uses special techniques to look inside.

[Peter] The archaeologists keep the artifacts

in special tanks of water.

They're also using x-ray techniques to take a look at the artifacts

without taking them apart or damaging them.

[Martijn] We can't start to chisel a concretion if we don't know

what's in there, so we really have to look into the object,

and only then we can see that this is a coin,

the coin is of silver,

so we have to be very careful to chisel it out.

[Jeremy] They discover that many smuggled silver coins

are mixed in with personal accessories like buckles

and beads and are found across a wide area.

[Michael] If the shipwreck is spread out over 600 feet

on the seabed, you know, how did they bring it altogether,

to help it make sense?

[Jeremy] The excavations give the team a wealth of information,

but it's not enough to identify the smugglers.

Who exactly were they,

and how much were they carrying?

Researchers must turn to the archives.

By scouring historical records,

sometimes you can find a paper trail.

[Martijn] All these things have a little traces

to somebody, and that's exactly what we did.

With the help of a lot of people searching

for those archives.

[Jeremy] Cross-referencing the date of the ship's departure

against bank records, they uncover evidence

of large and highly suspicious loans.

Daniel Ronzieres, the Rooswijk captain,

borrows 17,000 Dutch guilders just before the ship sailed,

the equivalent of $200,000 in today's money.

And he wasn't alone.

Some normal sailors had quite a lot of money with them.

That's how we found out that there was not just a little bit

of smuggling money on board,

there is loads of smuggling money on board.

[Jeremy] Working for the VOC was one of the toughest

and most dangerous seafaring jobs.

Did the rewards outweigh the risks for the 237 men

who went down with the Rooswijk?

[Lisa] If you were caught with this silver,

having it confiscated would be punishment enough.

You would return home, heavily in debt

and face debtor's prison or worse.

[Jeremy] And the wreck of the Rooswijk

may still have more to tell us.

[Rob] Archaeologists have only found the stern of the ship,

and so a large section is still unaccounted for.

Has it been ravaged by the sea?

Or is it waiting somewhere out there in the sea floor,

yet to be discovered?

Over the centuries, 246 Dutch VOC ships

have sunk to the bottom of the sea.

If silver smuggling was as rife on these ships

as researchers now believe, there could be millions

of dollars' worth of illicit treasure hiding in the deep.

The world's coastlines are teeming with life,

with the majority of ocean creatures

swimming near our shores.

People thrive here too with 40% of the Earth's

human population living close to a coast.

So what happens when this crowded zone

becomes a toxic wasteland?

The Kamchatka peninsula,

a pristine and remote wilderness

with towering volcanic peaks

and dark sweeping beaches.

Kamchatka's shores are where eastern Russia

meets the vast North Pacific Ocean.

In September 2020,

several surfers are enjoying the waves

when suddenly they're hit by a strange sickness.

Surfers in the water describe a variety

of adverse reactions, including nausea,

headaches, and burning and itching eyes.

[Jeremy] Some report what feel like chemical burns.

More than 15 surfers are hospitalized.

They report the incident to local authorities,

but within 24 hours Kamchatka's waters go from bad to worse.

Video captured by beach goers reveals a scene

of mass death.

[Helen] Lots of marine wildlife starts washing up

on the beaches, dead or sick.

It didn't matter what level of animal life

in the sea you were talking about.

Everything was dying.

[Jeremy] Underwater footage shows the sea floor

is now a marine graveyard.

Even stranger, some creatures look like

they've been boiled alive.

Scientists estimate some 95% of sea life

has been wiped out.

There's something deadly in the water here,

but we don't know what.

Could this be a manmade disaster,

or an act of Mother Nature?

[Jeremy] As the bizarre incident gains global attention,

international observers suggest there is one culprit

capable of causing such widespread death

and destruction.

Kamchatka's mighty volcanoes.

One hypothesis is that volcanic activity

could be to blame.

[Jeremy] Kamchatka has over 300 volcanoes

densely packed across the peninsula.

Well, over 20 of these volcanoes are known

to be active.

They can erupt with explosive force,

but it's the toxic gases they spew that can be just as deadly.

Around 20 miles from Kamchatka beaches,

Karymsky Lake lies next to a volcano

that was once thought to be extinct.

But on January 2nd, 1996, the volcano erupts.

A sulfurous plume rains down,

transforming the nearby lake into a toxic soup.

[Lisa] An ecological catastrophe ensues.

The water in the lake becomes extremely acidic.

All but the most simple versions of algae

and bacteria cannot survive in this environment.

Everything else dies.

[Jeremy] But around the time of Kamchatka's mass sea life deaths,

there are no reports of the seismic shockwaves

that usually accompany an eruption,

so volcanic activity is ruled out as the cause.

Instead, Russian officials suggest

a different natural phenomenon could be to blame

for this bizarre watery disaster.

Satellite images reveal a strange

yellow discoloration along the coast.

It prompts Russian researchers to link

the catastrophe to a known ocean killer, algae blooms.

[Alexander] It's like a cancer of the ocean.

It sucks up all the oxygen, all the nutrients.

It will take over an entire ocean if it is not controlled.

[Jeremy] In the US, red tides ravage coastlines each year.

Blood colored microorganisms produce toxins

that accumulate in shellfish,

making any creatures that eat them sick or even worse.

It speeds on through the chain of marine

ecosystem all the way up.

[Jeremy] Other species of blue green algae,

called cyanobacteria,

can also release harmful toxins.

Humans who come into contact can suffer skin irritation,

fevers and breathing difficulties,

the same symptoms experienced by the Kamchatka's surfers.

Did they encounter toxic algae as it washed ashore?

Some people think that Russian officials are quite keen

to push this idea that algae blooms

are to blame in order to move the attention away

from possible other reasons for it.

It seems that this might not be the full story.

[Jeremy] Environmental scientists conducting

their own separate investigation find something shocking.

Evidence of industrial chemicals in the water.

A secret source leads the scientists to a site

near Kamchatka's coast known to harbor decades old industrial waste.

Could it be that some of the chemicals that were

dumped here 'cause they were deemed too toxic

for industry are related to this problem?

[Jeremy] Are thousands of dead sea creatures in fact

the victims of a sinister manmade disaster?

On the coast where Russia meets the North Pacific,

a deadly poisonous soup has wiped out 95% of ocean life.

Can water analysis reveal the identity

of the mysterious killer?

[Lisa] Such a mass die-off of marine creatures

is unusual and strange, and needs to be investigated.

[Jeremy] Samples from the ocean reveal concentrations

of several unexpected toxic agents.

2,4-dichlorophenol is a compound used in pesticides.

Highly corrosive, it causes severe skin and eye damage in humans.

Another, tetrachloromethane, banned because of its toxicity,

can cause liver and kidney failure.

What we're seeing here is some kind of pollution event.

[Jeremy] But where did it come from?

Just five miles inland is an isolated industrial compound

called the Kozelsky chemical landfill.

For decades the site has been used to store barrels

of poisonous and hazardous chemicals in the ground.

[Jeremy] The site is in a derelict condition.

The chemicals are actually seeping into the ground water.

[Lisa] If any of these toxic substances get into the ground water,

it makes sense that they would flow into the ocean,

right where this massive die-off occurs.

[Jeremy] Despite evidence linking the Kozelsky

chemical landfill to the mass marine deaths,

Russian officials publicly deny it.

Then, in 2021, in a strange turn of events,

authorities announce plans of a cleanup operation.

It seems odd that they would make plans to clear out

and liquidate this facility just months after these claims.

[Jeremy] With Russian officials refusing to admit guilt,

environmentalists are now closely monitoring

the beaches of Kamchatka,

amidst fears that the toxic waters could return.

This is a real problem,

because this area is so rich in the ecological system.

It has some fantastic wildlife.

It's very important that we need to protect these waters.

[Jeremy] Whether it was an act of nature

or industrial neglect, the sea life massacre

along the Kamchatka coast should serve as a warning.

The world's coastlines are a turbulent

and blurred boundary between land and water.

In a place where humans and ocean creatures must coexist,

where and when will the next toxic disaster strike?

[intense music playing]

Across the vast blue expanses of our planet,

there's a bizarre invasion underway.

Multiplying armies of jellyfish are taking over

large areas of the world's oceans

where they've never seen before.

Why are these freakish gelatinous lifeforms

suddenly dominating our seas and what could it mean for us?

[Lisa] Jellyfish have been around for 500 million years.

They not only populate our coastlines,

but they've also been found up to 2.5 miles deep

underneath the ocean.

[Alexander] Jellyfish are freaky.

We have no real understanding of them.

They have no brain as far as we can tell.

[Jeremy] They may be very simple lifeforms,

but venomous tentacles make jellyfish

some of the most fearsome underwater inhabitants.

I handled one of the world's deadliest creatures,

the box jellyfish.

No one should approach these translucent terrors

without extreme caution.

This one has enough venom to kill 50 people.

I still can't compute the deadliness

of the venom of this thing.

This would kill people in a very, very a short time.

These toxins are found in a cell that we call

the nomadasis, which are like little daggers.

As the tentacle rubs up against you,

it's like a harpoon,

and that injects a toxin into the victim.

You're in a bad situation there.

[Jeremy] Not all species have lethal stinging power,

but in huge numbers they present a different kind of danger.

Studies now show that some 2,000 different species

of jellyfish are turning up at unexpected times of the year

in greater volumes than have ever been seen before.

One of the most bizarre phenomena in today's natural world are jellyfish swarms.

Increasing jellyfish numbers around the world

has puzzled scientists for decades.

[Jeremy] Researchers aren't sure why this is happening,

but one leading theory is overfishing...

which has depleted our oceans worldwide.

[Alexander] With the fish gone, the jellyfish have access to all the food,

so therefore their numbers grow exponentially.

[Jeremy] And in a frightening twist, this jellyfish plague

is wreaking havoc on some of the most

dangerous structures on the planet.

[Michael] For a non-thinking animal,

to take down a nuclear power plant...

It's pretty phenomenal.

[Jeremy] Across the world, multiplying armies

of jellyfish are overwhelming our oceans.

And now they threaten our coastal infrastructure.

July, 2020, in Israel, workers mount a massive cleanup

after thousands swarm a coastal power station.

[Lisa] Video footage from the power plant reveals

images of hundreds of blue jellyfish

being swept down the chute and into a bin.

[Jeremy] The plant needs a constant supply of cold sea water to run,

and its complex filter systems

are no match for the mysterious onslaught

of jellyfish seemingly intent on shutting it down.

These washed in from the Mediterranean,

blocking the critical cooling system.

[Dijanna] If the cooldown system goes down,

that means trouble for the power plant.

[Jeremy] It would be a costly setback for a coal plant,

but for a nuclear power station, a jellyfish invasion

has the potential for catastrophe.

In the last decade, four countries have been forced

to shut down nuclear plants because of jellyfish swarms.

Without cold water to cool their reactors,

meltdown is a real possibility.

Jellyfish can literally take out a nuclear power plant.

That's crazy.

[Jeremy] Why do these gelatinous zombie hoards

seem to hone in on our nuclear reactors?

Is there something in the water that's attracting them?

What is now known is that these strange creatures

absorb radioactive compounds from the ocean.

In 2015, scientists discovered radiation

in three sets of jellyfish.

Could there be a connection between radioactivity

and these bizarre jellyfish invasions?

[Jeremy] Scientists think these ocean drifters somehow accumulate radionuclides,

radioactive atoms found in the sea.

When radioactive compounds accumulate in sea jellies,

we can have a really big problem.

It's called bioaccumulation.

This contamination can travel through the entire food chain.

[Alexander] Jellyfish are the world's filtration system.

They go through the oceans and they pick up

everything that's flowing through it.

So if the world's oceans have radiation in them,

they're gonna pick it up.

[Jeremy] Could this radioactivity be affecting

jellyfish evolution?

Scientists are now finding that jellyfish

all over the world are getting bigger.

Over the last four years, the shores of Japan

have been invaded by the giant nomura jellyfish.

Growing to more than six feet in diameter

and reaching over 400 pounds in weight,

they are truly gargantuan.

[Alexander] In 2009, a Japanese fishing trawler

was sunk by giant nomura jellyfish.

They were the size of cars,

and they were hundreds, if not thousands of them,

all around the trawler, overwhelming it.

[Jeremy] To limit the destruction

caused by these enormous creatures,

scientists are desperately trying to predict where swarms will occur.

[Alexander] The problem really, with jellyfish,

is that they appear out of the blue,

and we can't really predict

when they're gonna come, or where they're going to come.

[Jeremy] Scientists know that overfished areas

of the ocean allow jellyfish

to thrive and multiply, but they might be even

stranger forces driving them towards our coastlines.

Jellyfish swarms could be controlled by the moon.

In 2016, a research scientist makes inroads

into why and where jellyfish blooms may occur.

He finds that they maybe connected to the lunar cycle.

[Jeremy] Data shows that big swarms occur

in the days before and during a full moon,

but we have no idea why.

We do know many other animals, including to an extent humans,

are impacted by the lunar gravitational fields.

[Jeremy] There's no obvious way to fight back

against this sinister wave of slime.

In fact, it's thought that as the world's human

population increases, so will the environmental

conditions that favor jellyfish.

But we don't have enough historical data

to determine if this is a natural fluctuation

or if the jellyfish army is here to stay.

New species of jellyfish are discovered every year.

They are on our coastlines, they're 2.5 miles down

in our oceans, they're everywhere.

They seem to be evolving,

and more seem to be coming about.

What's the next chapter in the evolution

of this resilient and long-living type of species?

[Jeremy] In a final terrifying twist,

it's now thought that our gelatinous adversary

has the ultimate weapon in its arsenal... immortality.

Humans have very clear age-limits,

because our cells begin to regenerate slower,

and we lose our ability to grow new tissue

in the way we would when we're babies.

Jellyfish, on the other hand,

don't have those mechanisms, so some people theorize

they might be able to live forever.

[Alexander] We really don't understand them.

They could be the key to unlocking eternal life.

We don't know.

The rise of the jellyfish shows no signs of slowing down.

Experts now think that within 40 years,

they'll be the dominant species in many marine ecosystems.

Unless we find a way to stop it,

this spineless invader is in line to become

the new King of the Ocean.