The mysterious world of underwater caves

I'm an underwater explorer,

more specifically a cave diver.

I wanted to be an astronaut
when I was a little kid,

but growing in in Canada as a young girl,
that wasn't really available to me.

But as it turns out,
we know a lot more about space

than we do about the underground waterways
coursing through our planet,

the very lifeblood of Mother Earth.

So I decided to do something
that was even more remarkable.

Instead of exploring outer space,

I wanted to explore the wonders
of inner space.

Now, a lot of people will tell you
that cave diving is perhaps

one of the most dangerous endeavors.

I mean, imagine yourself
here in this room,

if you were suddenly
plunged into blackness,

with your only job to find the exit,

sometimes swimming
through these large spaces,

and at other times crawling
beneath the seats,

following a thin guideline,

just waiting for the life support
to provide your very next breath.

Well, that's my workplace.

But what I want to teach you today

is that our world is not
one big solid rock.

It's a whole lot more like a sponge.

I can swim through a lot of the pores
in our Earth's sponge,

but where I can't, other lifeforms

and other materials
can make that journey without me.

And my voice is the one
that's going to teach you

about the inside of Mother Earth.

There was no guidebook available to me

when I decided to be the first person
to cave dive inside Antarctic icebergs.

In 2000, this was the largest
moving object on the planet.

It calved off the Ross Ice Shelf,

and we went down there
to explore ice edge ecology

and search for lifeforms beneath the ice.

We use a technology called rebreathers.

It's an awful lot like the same technology
that is used for space walks.

This technology enables us to go deeper

than we could've imagined
even 10 years ago.

We use exotic gasses,
and we can make missions

even up to 20 hours long underwater.

I work with biologists.

It turns out that caves
are repositories of amazing lifeforms,

species that we never knew existed before.

Many of these lifeforms live
in unusual ways.

They have no pigment,
and no eyes in many cases,

and these animals are also
extremely long-lived.

In fact, animals swimming
in these caves today

are identical in the fossil record

that predates the extinction
of the dinosaurs.

So imagine that: these are like
little swimming dinosaurs.

What can they teach us
about evolution and survival?

When we look at an animal
like this remipede swimming in the jar,

he has giant fangs with venom.

He can actually attack something
40 times his size and kill it.

If he were the size of a cat,

he'd be the most dangerous thing
on our planet.

And these animals live
in remarkably beautiful places,

and in some cases, caves like this,
that are very young,

yet the animals are ancient.

How did they get there?

I also work with physicists,

and they're interested oftentimes
in global climate change.

They can take rocks within the caves,

and they can slice them
and look at the layers within with rocks,

much like the rings of a tree,

and they can count back in history

and learn about the climate on our planet
at very different times.

The red that you see in this photograph

is actually dust from the Sahara Desert,

so it's been picked up by wind
blown across the Atlantic Ocean.

It's rained down in this case
on the island of Abaco in the Bahamas.

It soaks in through the ground
and deposits itself in the rocks

within these caves,

and when we look back in the layers
of these rocks, we can find times

when the climate
was very, very dry on Earth,

and we can go back many hundreds
of thousands of years.

Paleoclimatologists are also interested

in where the sea level stands were
at other times on Earth.

Here in Bermuda,
my team and I embarked

on the deepest manned dives
ever conducted in the region,

and we were looking for places
where the sea level

used to lap up against the shoreline,

many hundreds of feet
below current levels.

I also get to work with paleontologists
and archaeologists.

In places like Mexico, in the Bahamas,
and even in Cuba,

we're looking at cultural remains
and also human remains in caves,

and they tell us a lot about some of
the earliest inhabitants of these regions.

But my very favorite project of all
was over 15 years ago,

when I was a part of the team
that made the very first

accurate, three-dimensional map
of a subterranean surface.

This device that I'm
driving through the cave

was actually creating a three-dimensional
model as we drove it.

We also used ultra-low frequency radio
to broadcast back to the surface

our exact position within the cave.

So I swam under houses and businesses
and bowling alleys and golf courses,

and even under
a Sonny's Barbecue Restaurant,

Pretty remarkable, and what that taught me

was that everything we do
on the surface of our Earth

will be returned to us to drink.

Our water planet is not just
rivers, lakes, and oceans,

but it's this vast network of groundwater
that knits us all together.

It's a shared resource
from which we all drink,

and when we can understand
our human connections with our groundwater

and all of our water resources
on this planet,

then we'll be working on the problem

that's probably the most important
issue of this century.

So I never got to be that astronaut
that I always wanted to be,

but this mapping device,
designed by Dr. Bill Stone, will be.

It's actually morphed.

It's now a self-swimming autonomous robot,

artificially intelligent,

and its ultimate goal is to go
to Jupiter's moon Europa

and explore oceans beneath
the frozen surface of that body.

And that's pretty amazing.

(Applause)