Great Barrier Reef 3D

Welcome to Australia.

We're currently in the northeast of the Australian continent,

and beneath us lies the Great Barrier Reef.

The magnificent, clear water stretches as far as the eye can see.

Beneath the surface lie the coral reefs

that have spread across the entire area,

huge structures already visible from the air.

A truly exhilarating view.

What we can't see from up here is an astonishing variety of life forms,

waiting for us in the reef's depths.

They are the reason for our visit to this marvel of nature.

The Great Barrier Reef is the largest coral reef on the globe.

It lies by the east coast of Queensland State

at a length of about 2300 kilometers.

The total area covered by the reef

spans a stunning 350,000 square kilometers.

It's home to an incredible abundance of life.

2600 types of fish, 600 types of corals,

and clams up to 120 years of age are among its inhabitants.

Since 1981, the Great Barrier Reef

is part of the UNESCO World Heritage.

We meet with a true veteran of the Great Barrier Reef,

a man whose life is deeply connected with the reef now

for over 40 years, the American-born John Rumney.

In 1974,

I came here to Australia

to experience the Great Barrier Reef.

I didn't really know.

I'd read about it in National Geographic and books.

And, came up the coast

and in fact went out of Cairns to Green Island,

and that was the only tourism.

There was no-- Everything you see today,

the $6 billion industry, 60,000 people.

None of that existed.

It was just a few fishing boats

and this one ferry that used to go to Green Island.

Got there, jumped off and it was amazing, mind blowing.

The dance of life,

the next hour that you're in the water,

you will see more animals than you will the rest of your life.

I had done snorkeling when I was like, 11 or 12,

for the first time, and I think that was my change of life.

Because it went from being--

Just generally loving animals, snakes, lizards, crocodiles, things like that,

and once you were in the water, then it was 3D.

It was, you know, in your face

and so much more, being in nature, in a forest or in the mountains.

When you jump in like a Barrier Reef coral reef,

it's just hundreds of things and thousands of them.

Once we start diving below the surface,

we have to agree with John Rumney.

It's overwhelming just how colorful, alive,

and densely populated the reef happens to be.

Among the fish we see gigantic swarms.

On one hand, there are larger groups of fish

that roam the reef together.

On the other hand, we find dozens of tiny, colorful fish

that stay close to their corals along with other fellows of their kind.

This way, they can quickly hide inside the branching structures

when danger is nearby.

Of course, the corals themselves are a feast for the eyes.

With over 500 different species that inhabit the reef,

the corals impress with countless forms and stunning colors.

After all these impressions,

it's evident just why John Rumney made the decision

to stay in Australia.

He started out in the fishing industry

and later went on working in tourism.

During this time,

he made use of every opportunity to snorkel

and enjoy the enchanting act that presented itself underwater.

This way, he experienced the spread of tourism first-hand.

In present day,

it's an industry that employs over 60,000 people

at the Great Barrier Reef alone,

and makes annual sales in the billions.

But with time, Rumney noticed transformation in the reef.

Throughout the years, a grave problem began to appear

that now turned into a threat

to the rich diversity of species in the Great Barrier Reef.

A growing number of the corals are dying.

It's been an evolution.

Ah, coming here and first seeing the reef

in an incredibly vital, vibrant, pristine condition

and now, over the years, it's just decreased over time.

And, with this last bleaching event of 2016,

it's been like, it's so emotional.

It's completely changed and you went,

"Wow, this was a global warning."

This is the canary in the coal mine.

This is the turning point for me that we know

we must really act now or we will lose the Barrier Reef.

We won't lose all the coral in the world, no.

But we might go into the dark ages of coral, right?

It won't be what we see today.

We won't have the fish, we'll lose the biodiversity.

We'll even possibly lose our food security.

We are, out of our ignorance and lack of commitment,

really tampering with the basic physics of the ocean.

And that could be catastrophic.

The bleaching event that John Rumney refers to

bears this name for a reason.

Actually, the term is quite fitting.

A major part of the reef consists of limestone,

naturally of white color.

It formed from coral excretions

and functions similar to a skeleton.

The corals receive their varying colors

from a symbiotic relationship with different types of algae,

a relationship of mutual partnership.

The algae supply the corals with oxygen and energy.

But these algae are very sensitive when it comes to their environment.

A change in the water's chemistry or just a change in temperature

can cause a devastating chain reaction that kills off the symbiotic algae

and thereby results in the death of the corals.

This way, the bleaching event of 2016

caused a vast number of algae and corals to die off,

leaving nothing but blank, white limestone.

This became the term's infamous origin.

The event left nothing but a spooky wasteland.

It's even more frightening

when one knows of the abundance of life

that populated this place just recently.

With this in mind, the dead corals appear

just like a large pile of carcasses,

almost resembling a Dunning graveyard.

However, this hasn't been the first time.

Between 1985 and 2012,

the total coral covering of 28%

shrunk by more than half of that amount

to an alarming 13.8%.

Further drops ranging from five to 10 percent

over the next 10 years are thought to be inevitable,

caused by humanity's emission of carbon dioxide.

Well, I think that the Barrier Reef is the first symbol,

the first visible example of what is coming.

Like, yes, the corals are sensitive to temperature.

So, we've had a definite temperature rise

due to the CO2 emissions.

With this coral bleaching,

we're having this definite affect on the reef health

and many of the corals are dying,

so the next event, more will die and more will die.

So, this is a process of deterioration.

What we will lose, is the biodiversity.

The most different species in a given area

are right here on Barrier Reefs.

You know, thousands of times more animals per 100 meters

than in other parts of the ocean.

That very variety that Rumney speaks of

and that we witness around us,

is what makes the Great Barrier Reef so unique.

But where does this variety come from in the first place?

First and foremost, it's the work of the corals themselves.

The main actors in our globe's reefs

are the stone and fire coral.

Over the course of many millennia,

these living beings created giant formations

and even entire islands.

Among those are the Bahamas, Bermuda, and the Maldives,

but none of these are larger than the Great Barrier Reef.

Corals even compete with us humans

as the constructors of the largest connected structures on our planet.

Corals, being part of the group Cnidaria ,

achieve this by constantly releasing limestone.

The symbiodinium, a microorganism

that lives in a symbiotic relationship with the coral,

helps with the calcification and supply.

The symbiodinium supplies the coral with hydrogen,

and when it comes to the water's temperature,

they are very sensitive.

It always has to remain between 20 and 30 degrees Celsius,

which is why they're mostly found in flat, tropical,

and light-flooded waters.

Stone and fire corals

are nothing but gigantic colonies of single polyps.

Every single polyp is only about one centimeter in size.

Despite the food supplied by their symbiotic partners,

their diet consists mostly of plankton organisms

that they catch using their tentacles.

Fire corals are named after their stinging cells,

which they can use to break through the human skin

and inject a painful poison.

The symptoms are similar to those of touching poison ivy,

where the pain can last from two days up to two weeks.

The injuries can even lead to scars

that sometimes remain visible for a lifetime.

Divers should be especially careful

not to make the common mistake of confusing a fire coral with seaweeds.

In order to protect themselves

and fight for their space in the reef,

corals make use of so called defense polyps

that are larger than the normal ones.

They can use them to inject a poison

into the opponent's tissue, thereby destroying it entirely.

When it comes to the spreading among sessile species,

the ones that are unable to move about,

fire corals are very successful.

In the battle for light and space,