It's built entirely of coral reefs.

The reefs of the Dead Sea.

He dreams of coral reefs and plankton.

Those reefs at Discovery Bay, Jamaica were the most studied coral reefs in the world for 20 years.

And that's more or less the story of the coral reefs of the Caribbean, and increasingly, tragically, the coral reefs worldwide.

and coral reefs and rakishlooking craft in the offing.

And the view of scientists about how coral reefs work, how they ought to be, was based on these reefs without any fish.

But we have started studying pristine reefs only very recently.

There is an area that is the oceans, coral reefs.

And on top of the coral reefs are sand banks.

The main framework material of coral reefs is calcium carbonate.

That's bad news for coral reefs and oxygen producing plankton.

Here, in Samoa, in one of the most beautiful reefs,

Indian isles by coral reefs commerce surrounds it with her surf.

And this is something that is very unusual in today's coral reefs.

Coral reefs are growing slower in some places because of this problem.

This view of the world is a consequence of having studied degraded reefs.

For those of you who've been there, fantastic coral reefs, fantastic diving, fantastic snorkeling.

And the reefs disappeared, and new islands formed, and we thought, Well, we're real smart.

We've actually kind of made an ethical choice in society to not have coral reefs.

But at least on coral reefs are systems where there is a bottom component with structure.

And if the bleaching doesn't go away if the temperatures don't go down reefs start to die.

If we don't have fishing because these reefs are protected by law or their remoteness, this is great.

And all the fish species that depend on the coral reefs are also in jeopardy as a result.

When we went to pristine reefs, we realized that the natural world was upside down this pyramid was inverted.

People came to study our reefs from Australia, which is sort of funny because now we go to theirs.

Half the coral reefs are still in pretty good shape, a jeweled belt around the middle of the planet.

On the scale of decades, in our lifetimes, we're going to see a lot of damage to coral reefs.

I had to focus all my energies towards going to find new species of things down on deep coral reefs.

And on coral reefs, where some of the main framework organisms disappear, we will see a major loss of marine biodiversity.

A great deal of this has been happening in the Great Barrier Reef, particularly in coral reefs all over the world.

coral reefs all over the world, because of global warming and other factors, are bleaching and they end up like this.

What we found in coral reefs is that the inverted pyramid is the equivalent of the Serengeti, with five lions per wildebeest.

The coral reefs of the north coast of Jamaica have a few percent live coral cover and a lot of seaweed and slime.

Oyster reefs also covered about a quarter of our harbor and were capable of filtering water in the harbor in a matter of days.

And where the diver is, this is probably where most of the reefs of the world are now, with very few corals, algae overgrowing the corals,

But business as usual means that in 50 years, there may be no coral reefs and no commercial fishing, because the fish will simply be gone.

The people in Chicago decided that as well as exhibiting our reefs, what they wanted to do was have the local people there make a reef.

Ocean acidification is a really big issue that people are concerned with, as well as ocean warming, and the effects they're going to have on coral reefs.

Now, as I showed you in the earlier diagram, these reefs that we dive on start out near the surface and they go almost vertically, completely straight down.

And I ended up in Jamaica, in the West Indies, where the coral reefs were really among the most extraordinary, structurally, that I ever saw in my life.

But it turns out there is a very good reason why we are crocheting it because many organisms in coral reefs have a very particular kind of structure.

Most of the reefs are dead, most of the corals are dead overgrown by algae and most of the fish are smaller than the pencils we use to count them.

An hour with my trophies... and they usually do their best to keep away from me. Where do you get these poor devils? Providence provided my island with dangerous reefs.

It goes through it like a windstorm and you lose again the last bit of ash and nutrients to the first rainfall going to the sea killing off the coral reefs there.