>>NARRATOR:
Six years, 22 countries,

close to 200 scientists,

and one exceptional
research vessel.

The global reef expedition
is on a mission to stud

coral reefs around the world.

>>Coral reefs are undergoing
a worldwide crisis,

and we are trying to understand

where the healthiest reefs
remain,

what sort of factors
make those reefs healthy,

and, reefs that have
been degraded,

how we can help them recover
and persist into the future.

>>NARRATOR: To do so,
expedition scientists conduct

a number of studies
in the field.

>>We are applying
a standard protocol

that was developed through
a consortium of scientists,

and we think this
will be incredibly beneficial

to the world of science
and management of resources,

because now we can
truly scientifically compare

one reef to another,
from one region to another.

We operate under this banner
of "science without borders."

It is basically because there
are no political boundaries

between the oceans,
it is all connected.

And what you do in one location
can affect another location.

Every country we go to, we work
with the government agencies

and whatever universities
are there to identif

local participants.

And we bring them out with us,
first to get them to places

that they can't normally
get access to;

second: to show them
what we are doing.

We try to provide training
to them so that the

pick up some of our methods
and carry it on.

>>It's a two-way street,
because the local knowledge

is immeasurably important
to our research.

And then the local scientists
benefit by interacting

with world-renowned scientists
from very prominent universities

and organizations.

What every single country says
is that their biggest limitation

to really enacting
sound conservation strategies

is lack of scientific
information.

So our ultimate hope is that
the research will influence

action on the ground.

And so we are acting
as a catalyst.

We're an accelerant to change.

>>Major funding
for this program was provided

by the Batchelor Foundation,

encouraging people
to preserve and protect

America's underwater resources.

And by Divers Direct,
inspiring the pursuit

of tropical adventure
scuba diving.

(beachy music playing)

>>NARRATOR: Tahiti, Bora Bora,
the islands of French Polynesia

evoke visions of an exotic
tropical paradise.

Located in the South Pacific,
about halfway between

South America and Australia,
the island nation is made up

of five archipelagos.

>>French Polynesia has hundreds
and hundreds of islands.

And it is spread out
in a massive geographical range.

>>It is the size
of western Europe, basically.

>>These islands-- some of which
have been studied extensively--

others have never been
surveyed by scientists.

And it is really exciting
to go research areas

that you know for a fact
no other human has visited,

and certainly never conducted

any systematic
scientific research.

>>We're trying to compare reefs
that are in a similar region

across what I call gradients
of human disturbance--

and what I mean by that is,
going from very populated areas

to very unpopulated areas.

And it will help answer a lot
of the questions that we have

about resilience and how that
is related to human impacts.

>>NARRATOR: The global reef
expedition is organized

and funded by the Khaled Bin
Sultan Living Oceans Foundation,

a U.S.-based
nonprofit established

by his royal highness,

Prince Khaled Bin
Sultan of Saudi Arabia.

>>Prince Khaled became
a scuba diver,

and really fell in love
with the ocean

and particularly coral reefs.

While he was diving
in the Red Sea,

and he had one reef
that was his favorite dive,

and so he went back there
a couple years later,

and he saw the deterioration
of the coral reef firsthand.

And so that really gave him
the initiative to do

what he could do
as a single person

to try to help preserve
these beautiful coral reefs.

>>NARRATOR: In 2011,
the global reef expedition

got under way in the Bahamas.

Since then, a dedicated team
of researchers has worked

its way across the Caribbean,
the Galapagos,

and to the South Pacific.

In each location,
science divers conduct

a rapid environmental assessment
to collect baseline data.

>>We want to know
what corals are there,

what fish are there,
what the bottom looks like,

what other types of organisms
are found there.

Right now we are on Rangiroa,
which is the largest atoll

in French Polynesia.

There is about 450 different
atolls around the world,

and French Polynesia
has more than any other country.

They have about 85 of them.

>>NARRATOR: Atolls are
ring-shaped coral reef islands

that surround a lagoon.

>>On these atolls,
we look inside the lagoon

and we look outside the lagoon
on the fore-reef.

>>NARRATOR: At each site,
the divers work

in a 100-square-meter area.

Dive buddy teams
collect different types of data.

One team collects information
on fish.

>>We lay a 30-meter transect
line.

This is attached to us
as we swim along the reefs.

>>NARRATOR:
As the divers work their wa

along their transect lines,
they identify and count

all of the fish species they see
within a four-meter radius.

>>We try to do as many
as we can.

Typically, we would be able
to cover maybe four transects

during one dive.

Around Rangiroa,
we find a lot of sharks,

which is typical for the area.

At the same time, we also find
a lot of herbivores,

such as surgeonfishes and
rabbitfishes or parrotfishes.

These species occur
in large schools

that swim around the reef.

And they are also
very significant in that

they have important roles
on the reef.

>>NARRATOR: Another team
of divers is conducting

benthic surveys,
which means they are studying

what lives on the sea floor.

>>I lay out a ten-meter-long
transect line,

and every ten centimeters

I record what is directly
underneath that point.

And I do this
to accurately record

what is on the bottom
of the reef,

and that helps us determine
how much of it's coral,

how much of it's sand,
how much of it's algae.

And then we do this
at different depths,

at every single reef,
multiple times,

and then that really helps us

to assess what each reef
looks like.

>>And then the third survey
approach focuses specificall

on the corals,
and we again use a transect.

We lay out a line
that is ten meters long,

and we assess every coral
that's within one meter

of that line.

So we are looking
at a ten-square-meter area.

And for all these corals,
we will identify what type

of coral it is.

We then measure its size,
and then we record information

on how healthy that coral is.

By measuring size,
it gives you information

on the current status
of that reef,

the past history of the reef,
and the direction

it is likely to go
in the future.

And so an ideal reef
would be one that

has a lot of different species
together, and it also has

a wide range of sizes.

>>NARRATOR:
Other divers conduct

what are called
photo-transects.

To do so, they use
a one-square-meter quadrat

made from PVC pipes.

>>And we will put
that quadrat down,

and we just flip that
over ten times

and take ten pictures.

Because we are limited on time,
you can only do

so many belt transects in there.

We get the same information
from these quadrats.

We can get cover and we can get
size of the corals.

>>The reason we collect
all this data

is because the more you know
about the reef,

the better you can manage
the reef.

>>We know that one
of the major factors

responsible for the global coral
reef crisis is climate change.

Seawater is getting hotter
than it has ever been before,

and so it is causing corals
to bleach and die.

Storms are getting more intense.

There is a growing threat
from where the oceans

are getting much more acidic.

>>That is a global problem
that is hard for reef managers

to really tackle.

But while that is a problem,
what they can do is make sure

that other factors aren't
a problem to the reef.

>>If we address a lot of those,
if we improve water qualit

in areas where
a lot of people live,

if we address some
of the fishing pressure issues,

if we do coastal development

in a more environmentally
friendly way,

I think we could reduce
those human impacts and make

the reefs more likely to persist
in light of climate change.

>>NARRATOR: Fortunately
for French Polynesia,

its coral reefs are doing
fairly well compared to reefs

in other parts of the world.

While they have been impacted
by coral bleaching,

intense storms,
and other natural factors,

human impacts are very low.

One of the biggest challenges
to marine research is access

to remote locations.

Conducting research at sea
is very expensive,

which is why many areas
are understudied.

To make the global reef
expedition possible,

Prince Khaled Bin Sultan donated
the use of one of his yachts...

...the 220-foot
"M.Y. Golden Shadow."

>>The "Golden Shadow"
really has an amazing suite

of capabilities.

There is a large stern elevator
that operates on hydraulics,

and that stern elevator can
lower right down in the water.

And its purpose was to recover
and launch

a Cessna caravan seaplane,

and that 12-ton stern elevator
can also be used to launch

some of the bigger tenders,
the dive boats that we use.

The principle dive boat
is a 36-foot catamaran

that we can put
up to 18 scuba divers

to do our surveys
on the coral reefs.

The ship has a very large dive
locker where we can

fill our dive tanks.

And in the event
of decompression sickness,

we have a recompression chamber,
which really is useful

when we are in remote locations
of the world and we don't have

medical facilities
readily available.

Also, one of the assets
of the ship

is extremely long endurance,
and so we can travel

about 10,000 miles
with one filling of fuel,

which allows us to access
remote areas of the world.

>>NARRATOR:
In recent years,

many of the traditional funding
sources for scientific research,

such as large government grants,
have declined.

>>I'm seeing more and more
private individuals

start to engage in things
like oceanographic research.

So when you see
these foundations stepping up

and filling this void,
it is very encouraging.

>>NARRATOR:
Another important aspect

of the global reef expedition
involves the creation

of large-scale maps
of the sea floor.

>>And the way we do that
is we start to acquire

satellite imagery
about a year before

we come to the location
with the ship.

So that's a very long process to
acquire pictures of the earth,

which aren't confounded
by clouds.

It's a very high resolution
and new satellite,

and the imagery allows us
to differentiate

the character of the sea floor.

So we can separate sea grass
from coral from sand

to all the typical
benthic habitats you find

in a coral reef environment.

>>NARRATOR: The mapping project
is spearheaded

by Dr. Sam Purkis and his team

from Nova Southeastern
University's

Oceanographic Center
in Ft. Lauderdale, Florida.

Once they have
all the high-resolution images

of an area in hand, they begin
ground-truthing on location.

>>We come in to the field
on the ship to start to relate

what the satellite
is seeing from orbit

to what is really happening
on the coral reef itself,

on the sea floor.

We can then start to get

even finer resolution
differentiating

between areas of coral,
which are live and vibrant

and healthy, versus those which
are in not such good shape,

or perhaps even completely dead.

So we can make a snapshot,

a large-scale,
regional-scale audit

of the state of the coral reef
at this point of time.

>>One of our
primary instruments

is an acoustic depth sounder,

and that is this
instrument here.

And he is set up so that he can
swing in to the water,

as I am doing now.

And this instrument pings
a couple times a second,

as we're moving along.

And you see he is pinging
quite quickly right now.

And right now it's about
14 meters deep.

And here you can see
the surface.

It is quite flat, so that
tells us that we are over sand.

Here you have the position,
the latitude and longitude

of each depth sounding
as it is being recorded.

>>So what I am getting ready
to do is to drop this camera

into the water.

It is a high-resolution
video camera with a weight

on the bottom and a fin to keep
it stable on 50 meters of cable.

So what we can do is,
we are going to lower

this into the water
down to just above the seafloor

and fly it along.

The camera is linked in
to a very accurate GPS

at the back of the boat
so we know exactly where it is,

and the bearing and the speed
that it is flying.

And that's the information
that we're collecting

to validate what we see
from the satellite.

>>Sam, when you're ready.

>>All right then, neutral.

>>That means neutral.

>>Here we go.

>>How's that, Jeremy?

>>Hold there.

>>Holding.

>>We can see where we are
on the satellite image live,

and we can see the video feed
coming from the tethered camera

on the sea floor as well, so we
know exactly what is going on.

>>All right, done.

>>Coming up.

>>Okay, that's done.

The last piece of the puzzle
is we have

a very low-frequency
acoustic sounder,

and we use that to examine
what's going on

beneath the sea floor itself,
so we can see how thick

a coral reef framework is.

And that gives us some idea
as to whether,

if we see a reef today
which is not very healthy,

we can see how well
that reef has been faring

over the last 10,000 to 6,000
years of growth.

And then we can see whether
it is anomalous,

whether the reef today
is unhealthy or not,

or really is it just
not a very good area

for a reef to be developing.

The technique of mapping
the ocean floor from satellites

is routinely used
but not at this scale.

Typically we look at areas

of 100 square kilometers or so
per year.

We are now covering
25,000 square kilometers.

And so these are
the largest applications

of the technology to date,
and that is very exciting

to be involved with.

>>NARRATOR: When all
of the fieldwork is done,

the scientists work up
their data

at the university's lab
in Ft. Lauderdale.

>>That is a fairly lengthy
process involving

computer programming,
and so there is

a mathematical manipulation
of the data set.

>>NARRATOR: Using a variety
of different computer programs,

the experts link
the depth values collected

in the field with
the light values depicted

in the satellite imagery
to create accurate bathymetry,

or depth maps.

>>We use the bathymetry
that we gathered in the field

to train an algorithm that then
says this amount of light

is an estimate for this
type of depth.

The ground-truthing becomes
our training set,

is what we call it.

So this says, we know in these
areas that this is what is here,

this is the water depth,
and from this...

now I need to extrapolate
to all of these other polygons

and pixels in my area
to make sure that

I am estimating things properly.

Our field efforts
tend to be intense,

because we need to get
as much information as possible

out there, to make sure
that when we come back

and do the statistics
and the math,

we have a strong set coming out.

>>NARRATOR: The team
also creates habitat maps

by assigning groups of pixels
in the image

to different habitat classes,
such as corals or sand.

>>And in this program,
I use the drop cam videos

and some of my own knowledge
to assign classes in the image.

So here I just select a bunch
of sand, and then classify it,

so now it is marking it
so that I know

that he has been called sand.

And I do that over
different depths so that

we have quite a range.

And here I will just assign
some reef.

>>NARRATOR: Using algorithms
and a variety of software,

the computer can then
extrapolate habitat classes

for the entire image.

>>It uses spectral values
or depth values

to then group
the pixels together,

saying this should be a reef,
this should be sand,

this should be land.

What this allows us to do
is to use only a few examples

from the image itself
to classify the entire image.

>>NARRATOR: Once the process
is complete,

the experts have created
two kinds of maps

that can be combined to make
a three-dimensional map

of the seafloor.

>>The fantastic thing
about the maps

is they're digital,
and they can be tendered

to the public
through the internet.

They can be housed in government
computer systems,

or they could be printed
into very large-format posters

or atlases.

>>You can see there is
a bathymetric map on the left,

a habitat map on the right.

Here on the water depth,
the red are the shallower areas,

with blue being moderate depths,
and blue being the deepest areas

that we can see.

And on the right,
when the habitat yellow is sand,

the reds and oranges
are different coral frameworks.

Green is algae or sea grass.

>>The data is very powerful
because the maps

we are producing set a baseline
which then can be revisited

through time to look

for regional-scale
ecological change.

>>NARRATOR:
Another science component

that will be incorporated
into the mapping process

is a study of the sediments
found on the sea floor.

What this is able to kind
of show us is a spatial pattern.

You can make sediment maps

using the sediment composition
dataset.

So we are able to map
the different gradients of sand

and how they are correlated
with the coral cover,

algal cover, and any sort
of storm disturbance.

>>NARRATOR: Nova Southeastern
University graduate student

Alexandra Dempsey collects
sediment samples on each dive.

>>We try to sample around
three to five vials of sand.

>>Collecting sediment
on the coral reef

is a little bit like taking
a blood sample for a human.

With a blood sample,
you can tell the condition

of the body and the health
and so on and so forth.

A coral reef, by the way,
it grows and decays.

It produces sediment.

And by collecting that sediment,
we can start to understand

the history of the reef.

It may seem like a rather
mundane thing to sample,

but we can gather great insight
about the coral reef

and its history by examining it.

>>When we return back
from the field

after collecting
sediment samples,

we go ahead and we wash them
and dry them in this lab,

and we run them through this
machine called the camsizer.

What a camsizer does
is measure each individual grain

to the shape of the grain,
its actual dimensions and area.

And it is able to tell us
what percentage of the sample

is a certain grain size.

You can tell a lot
by how large the grain sizes

are in a sediment sample,
where they come from,

if they are from
a specific type of coral,

or from an algae,
or from sponges.

>>NARRATOR: Alexandra can also
take a closer look

at sediment samples
under a microscope

to better understand
what may have happened

in a certain area over time.

>>If most of the reef is dead
and we really don't have

an explanation for it,
we can go ahead and look

into the sediment sample
and you can see what factors

have contributed to the downfall
of that specific site.

>>NARRATOR: One of the
big threats to the reefs

in French Polynesia
is crown of thorns sea stars,

which can eat large amounts of
coral in a short amount of time.

>>If we can see crown of thorns
spines, we can sa

that's one of the factors,
or the main contributing factor

to why a reef
is no longer healthy.

>>NARRATOR: All of the data
collected on each mission

is combined into
a geographic information system

that is available online.

>>And that is also handed
to the country itself.

So we are trying to provide them
all these geospatial tools

that they can then use
to implement conservation.

>>The global reef expedition is
really only the start of things.

We are gaining
great advanced knowledge

of how these
ecosystems function,

and how healthy they are.

But people will be able
to use these data,

I say, hundreds of years
in the future.

>>I really hope this research
that we do

and all these resources that
we are providing to the country,

that they are going to be used;
that these maps can help create

better management for the reefs,
and that the reports

we give them helps
the local stakeholders here

know their reefs better, and
therefore protect them better.

>>We have had a few
success stories already,

where some of the science
that we have collected,

they needed the information
in order to take

some sort of conservation step.

That's what's really rewarding.

When I see that we have
done this work,

it's good information for them.

But when they take
the next step,

and then do something that
is really going to protect

these reefs for the future.

Captioning sponsored by WPBT.