4 billion years ago,
as the molten Earth cooled, a vast world ocean was formed.
This sea became the cradle of life on Earth.
The ocean average is 2 miles in depth, and it's filled with life.
The underwater world supports lifeforms in a far wider diversity of shapes and colours ...
than exists on land.
The oceans encompasses creatures as delicate as the jellyfish, or as powerful as the whale.
Somehow they all fit together.
And we're just beginning to understand how.
Our growing knowledge is important.
We can't protect what we don't understand.
We live, because the sea lives.
Here, in the Islands of Balah,
the rhythm of our life is the rhythm of the sea.
We are born on a certain tide, we die on another.
The tide carries our boats out to the fish.
It brings us back to feed our families.
The seasons of our lives depend on different currents ...
that guide us to the schools of feeding fish.
Ocean currents caused by winds and the Earth's rotation,
circle the globe, linking what we once thought were many separate seas.
We now realise there is only one ocean —
the world ocean.
The waters of the world ocean wash the warm volcanic coastline of Hawaii.
These same waters lap against the frozen inlets of Alaska ...
and pulse through the Red Sea between Africa and the Arabian Peninsula.
These world currents also nourish the giant kelp of California ...
which can grow a foot or more in a single day.
The world's aquatic plants including kelp, provides 70% of the oxygen we breathe.
The world ocean is a single interconnected system.
For example, one current flows halfway across the world from Australia past Africa,
then joins the Gulf Stream in the North Atlantic.
Just as currents move the waters of the world oceans,
so do the tides which ebb and flow under the gravitational pull of the Moon.
High tides follow the Moon as it orbits the Earth.
Canada's Bay of Fundy on the Atlantic coast is famous for its immense tidal flow.
Up to a trillion tons of water enter and leave the Bay with each tide.
High tides can reach 50 feet and more.
Low tides empty coastal channels leaving veins of red mud.
The tides enrich the land, the land enriches the sea.
While the Moon's gravity tugs the world ocean to a depth of 1,000 feet,
winds churn its surface.
Ocean waves driven outward from fierce storm centers, often travel for a week or more,
until they explode against the land.
Large waves moving at speeds of up to 70 miles per hour,
surge across thousand of miles of open ocean.
When these waves approach the coast of Oregon, at Cape Disappointment,
they keep the U.S. Coast Guard busy.
Here they teach heavy surf rescue.
First thing cadets learn in this school is ... humility.
In the past two centuries,
over a thousand vessels had been lost here at Cape Disappointment.
When waves are small, Oscar, our search and rescue dummy, likes to take a swim.
- Man over board starboard side! - Darrell ... you got my pointer.
Search and rescue during calm water is no problem, but ...
we need to be able to rescue those in 15 foot seas. That's tough work.
They say a 15-foot wave can drop 200 tons of water on a boat.
The ocean size and power dominate our planet.
For centuries, sailors feared its distructive force.
Today, surfers meet it at the point of its greatest fury,
where they find themselves mysteriously at home.
You're riding these waves, that have traveled thousands and thousands of miles.
You know, you're at the mercy of the ocean.
You're underneath the waves and ...
you hear the rocks rolling around on the ocean floor an ...
you hear thundering ... of the waves ...
ye know it's just amazing.
It would be great to meet the waves forever.
Despite its great power,
the sea invites contemplation.
What is our place beside the immensity of the ocean?
For me, the ocean always has special significance,
just 'cause you're so close to nature.
There's so much life around you under the ocean —
there's fish — there's dolphins, and there's whales — there's sharks, there's ...
Heaven knows what else's swimming around you under you all the time.
There's where you feel as one ...
you sort of melt in and you really do feel part of the ocean,
which is a great feeling,
but you have to look for that now ...
where, I am sure a long time ago that was a natural kind of thing — an ocean person.
Our relationship with the sea is seldom very deep.
Most of our contact with it takes place on the surface.
We are drawn to the ocean,
but how do our ever increasing numbers threaten the health of the living sea?
To find out, we need to look beneath the surface.
Scientists at the Monterey Bay Aquarium Research Institute ...
use remote-controlled submersibles to study the ocean,
and monitor our impact on it.
We call it an ROV,
but officially, it's a remotely operated vehicle.
It's the underwater equivalent of a NASA space probe.
The deep sea project chief is oceanographer Bruce Robison.
Vehicle heading 189,
vehicle depth — 30 feet, moving down.
As the ROV descends to 1,500 feet, it enters the world below.
While we stay on the mother-ship, up on the surface,
the ROV dives, sending us back live video pictures.
On many dives, we find species never before seen by anyone.
Now 1,500 feet.
Is that the same species that you and George described?
I think so, but we're looking at it on the side, so it appears to have a different configuration.
Here, let me put it on a bigger monitor.
Hey, what is this showing up on the sonar screen?
On this particular dive, our sonar locked on to something big.
About half the length of a football field.
It was the first time we'd seen this type of Siphonophor.
We moved in on its head.
Look at the detail of that head.
You can see how the swimming bells pulse the valves close after their thrust,
so that water doesn't go back inside.
The Siphonophors is one of the most remarkable animals on Earth.
It sounds like science fiction,
but it's not.
It's actually made up of hundreds of separate specialized individuals.
The swimming bells are separate units, so are the stomachs,
so are the reproductive sections.
This animal is so huge,
it's hard to imagine all these individual units working together.
How many other creatures are there like the Siphonophor?
And what do they tell us about the vitality of the sea?
The middle ocean level is enormous.
And we've only studied a small fraction of its volume.
We've still got a lot of work to do.
All over the world ...
scientists are finding evidence of the connections that link the living sea.
What we do in one place affects the entire ocean.
Off San Diego, oceanographers are studying the impact of pollution on the kelp forests,
which are nurseries for spawning fish.
In the central Pacific, giant clams some weighing 400 pounds ...
faced extinction from over-harvesting.
Scientists then studied the clams spawning cycle.
An adult clam is both a male and a female. It releases millions of tiny eggs,
and then even more sperm.
Today, using simple techniques, scientists can make clam spawn.
They now produce over one million sea clams a year.
Here at the Monterey Bay Aquarium in central California,
sea otters that have lost their parents bond with the human trainer.
I try to teach the baby otter to hunt for food ...
It begans to think of me as its mother.
And after a year it's hard for me to return the baby otter to its own home — the open ocean.
Like the sea otter, the humpback whale was once hunted nearly to extinction.
In Bar Harbour Maine, Dr. Steve Katona leads a team studying the humpback.
The underside of the humpback's fluke is like a fingerprint —
No two have the same markings.
That's what allows Steve Katona to track them.
The first time a whale is photographed, it's given a name and number,
which we share with other research stations all over the Atlantic Ocean.
By matching our photos with other sightings, we follow the whales migrations.
Wrong pattern.
Once we identify the whales, we can count them.
There is no question the restrictions on hunting are working.
They're now over 12,000 worldwide, and the population is growing.
The expanding population of humpbacks is a measure of our growing love for the sea.
In one isolated group of islands that same wisdom, that same love, is called tradition.
The remote island chain of Palau located near the equator, east of the Phillipines,
gives scientists a rare look at a vanishing underwater world.
These waters may contain more species of marine life that any other place on Earth.
Historically, Palau's had little contact with the outside world.
Palauns still maintain their tradition of profound respect for the sea.
For 3,000 years, our ancestors lived in harmony with the sea,
never taking more than they needed.
Each family group worked a patch of reef. They tended this reef like a garden.
I'm Francis Toribiong.
Although he's old now, my father still swims the reefs with me.
Our waters are protected by a barrier reef.
That's one reason we have so many fish, so much life here.
I was born by the sea.
When I was a boy, I had fun making storyboards.
After the old men would teach us an ancient legend,
we tried to bring the story to life in a piece of wood.
This one, is about how these islands came to be.
All the stories are about our long-ago people.
We are islanders and our lifes are of the sea.
I think sometimes the traditional ways are still the best.
Even today, my children have one foot in the old world, and one foot in the new.
I try to teach the old ways to my daughter Julie and my son Wes.
It's ok with me if they like speedboats, as long as they respect the sea.
Today, I'm taking my children to an island they have never seen before.
We have over 200 rock islands in our waters. We call them floating gardens.
Mostly, we do scuba for fun, but also it's a kind of courtship.
I hope my children will fall in love with the sea.
We are lucky today. This the first time my children have seen a coral fish.
The coral fish is very shy and quite intelligent.
It can change its spots to communicate with other coral fish or can change colour for camouflage.
Since it's a type of squid, the coral fish can also release a thick cloud of ink.
That's why we don't want to get to close.
Coral looks like a plant, but it's really an animal.
When coral dies, it becomes like rock.
A new coral grows on top of the old skeleton.
Coral reefs are always growing.
They're the largest structures made by any living thing, even by us.
We know that what happens in other parts of the sea, touches our waters.
Far away, big factory fishing boats led many groopers in tuna.
Now, we seldom see these fish along our reef.
It's all one ocean.
This is what I'm teaching my children today.
Scientists also like to come here to learn.
They say our coral reefs, our fish, and our marine life still hold secrets.
We're flying south from the main island to one of the most bizzare ...
and potentially dangerous dive sites in all Palau.
With me is marine biologist Bill Hamner and his wife Peggy.
My name is Laura Martin.
I'll be here for five years ...
studying one of the strangest creatures in all the islands.
It lives here in this land-locked salt water lake.
We're studying this lake oddly enough to learn more about the world ocean.
At the end of the last ice age as sea level rose,
salt water filled the lake. Because it's small and enclosed,
what we call a closed system, the lake is like a test tube for scientific study.
Ocean species have been trapped in this salt water lake for thousands of years.
Today is my first visit ...
and I'm a little nervous.
Swimming into a mass of a million jellyfish you can expect to be stung.
But you don't.
These jellys have lost their need to sting.
Each morning over a million jellys gather ...
and travel together across the lake,
swimming almost a mile a day.
They follow the same path and the same schedule every day,
you could set your watch by it.
Yet, here's an organism, which has no eyes, no brain, following the complex migration pattern.
How do they do this?
These jellyfish follow the sun ...
because inside their bodies, each one maintains a crop of algae, which is its sole source of food.
It's roughfly equivalent to carrying around a portable vegetable garden.
The algae needs sunlight to grow.
Most jellyfish are hunters, stinging their prey before they eat them.
These jellys are farmers, so they don't need to sting.
We found that there are three distinct depth layers in the lake.
The top layer is like sea water.
The middle layer is thick with red bacteria.
Below that is a highly toxic layer.
At night, the jellys descend to this nitrogen-rich bottom layer of the lake ...
to fertilize their internal gardens.
As we descend into the poisonous layer to take samples,
Hydrogen Sulfate begins to enter my bloodstream through the skin,
excluding oxygen almost immediately. A wetsuit is no protection.
If we were down here 5 minutes, it could be fatal.
We only stayed 45 seconds.
These jellyfish, which Laura Martin will study for the next 5 years,
have shown a remarkable ability to adapt.
They have lived millions of centuries since before the time of the dinosaurs.
Yet they are among the most fragile creatures on Earth.
The ocean encompasses creatures as delicate as the jellyfish,
or as powerful as the whale.
Somehow they all fit together,
and we're just beginning to understand how.
Our growing knowledge is important. We can't protect what we don't understand.
What we understand most profoundly — we love.
Here, in the islands of Palau,
respect for the sea is passed down from mother to daughter,
from father to son.
It is carved into our storyboards: a woman once had a baby grow, the board says.
The child grew so large, that she fell into the sea.
The parts of her body that popped up above the surface ...
became our islands of Palau.
I love this story,
because it tells me that our lives and the life of the sea are all of one piece,
braided together.
Here, we are islanders. We live because the sea lives.
It really means a lot to me, that these huge and beautiful creatures ...
which came so close to extinction, are on their way back.
Whale populations are a yardstick I use to gage the health of the ocean.
By that measure, I think we have reason to hope.
Our efforts to sustain the life of the sea,
has made a difference.
Yet, scientist have shown us that the ocean environment is much more fragile ...
than we ever thought.
Because the land we live upon occupies only a fraction of the Earth's surface,
we are all islanders, no matter where we live —
for rain, for food, even for the air we breathe,
we all depend of the health of the ocean.
All life on Earth is a celebration of the living sea.