Nova (1974–…): Season 48, Episode 7 - Reef Rescue - full transcript
Marine biologists from the Bahamas to Christmas Island to Australia fight against the clock to save the coral reefs from extinction.
Coral reefs have captured
the human imagination
for as long as we have
ventured beneath the waves.
Towering, romantic, strong,
resilient,
but very ornate and,
and delicate at the same time.
There really is
nothing else like it.
Beyond their beauty
and brilliance,
coral reefs support
a quarter of all marine life
and are crucial for ocean health
and human survival.
But now these precious creatures
are in crisis,
as ocean heat waves
are bleaching corals
of all color and life.
By the end of this century,
coral reefs could be lost.
Can we help them?
Can we accelerate
natural selection?
Can we accelerate
adaptive rates?
On tropical reefs around
the globe,
scientists are fighting
a desperate race against time.
Unlocking the secrets of
millions of years
of coral evolution
and trying to speed it up.
If we are going to save
coral reefs,
we have to start intervening.
Their ideas are new
and experimental.
And for the first time,
their daring research
will be put to the test.
I think science and scientists
are being asked to
solve problems.
Honestly, we don't know
whether it's going to work.
The risk of doing nothing
is the risk of
risking every reef
on the planet.
"Reef Rescue,"
right now on "NOVA."
I will often describe it as
my cathedral.
If you could imagine a cathedral
with all of the
stained-glass windows,
all of that color is
splashed across the landscape,
with the fish
darting in and out.
It's the place I go
where I feel awed
by the complexity of
the architecture around me.
Coral reefs have been compared
to tropical rainforests,
and what I mean by that is
the diversity of the species and
how they're packed in together,
how they create
this kaleidoscope
of color and function.
When I go underwater,
each coral head
is like its own little city.
When you get to a
massive spur and groove system,
it's like downtown Atlanta,
super busy, bustling,
characters everywhere,
different sounds,
clicking and popping
and bubbling.
And it reminds you
that we are all one piece of
a community, or ecosystem.
Corals appeared
500 million years ago.
They may look like rocks,
but corals are in fact animals.
Each tiny coral creature
is called a polyp.
The polyp is essentially
a mouth with tentacles
used to trap floating food,
but most corals also have
another source of nourishment.
Inside the cells of the animal,
there is a tiny plant cell
and they, as all plants do,
are able to use the
energy of the sun, capture it,
to combine carbon dioxide
and water
into a small food molecule
and oxygen.
These microscopic plant-like
organisms are algae.
The algae feed the coral animal,
and the coral
gives the algae a home.
It's a dynamic
symbiotic relationship.
So much so that
the algae are called symbionts.
Reefs begin when coral polyps
secrete a thin layer of
calcium carbonate
to create a skeleton.
Hundreds and hundreds
of identical coral polyps
create a colony.
And over thousands of years
of growth,
coral colonies build the reef.
So animal, vegetable, mineral.
That is what a coral is.
Christmas Island is an atoll
in the Pacific Ocean
made entirely of coral.
Julia Baum is a
Canadian marine biologist.
For more than a decade,
she's studied the reef's
unique ecosystem
and the threats it faces.
It always feels great
to be back.
It's a bit of a mix of emotions;
there's, there's so much
invested in every single trip.
Always a little bit of
excitement
about an adventure
that's about to begin,
and also maybe
a little apprehension
just to make sure,
is everything going to go okay?
Hey!
Hi!
I think that it's actually,
I know it sounds crazy...
And then I think that...
but I think it's actually
you're gonna,
you're gonna drop there.
And that's...
It's Julia's first day out on
the reef this year.
Oh, did you...
The team dives down to
take stock of the coral.
When I first started doing
research on the ocean,
I had been so focused on
sharks and fish,
and at some point,
I think I kind of looked down
and saw the coral and realized,
"Hey, the coral
are the whole foundation
of this ecosystem."
And if we're worried
about this ecosystem,
we really have to be worried
about the coral themselves.
We have hundreds of corals
tagged all around the island,
and we take tiny tissue samples
from them.
We can take the photos
to identify individual
coral colonies themselves
and get a sense of who's there
in the community.
A brain coral is one of
the main types of corals
that we've been working with.
There's also branching corals
and flat corals,
so lots of different shapes,
and those are important
because they provide
different types of habitat
for fishes.
Each year, Julia and her team
meticulously tag,
sample, and photograph
40 plots of coral,
building a timeline of
how the reefs are changing.
During the
2015 and 2016 El Niño,
water temperatures here
increased by
four degrees Fahrenheit.
The heat set itself down
on this island
and just got a chokehold on it,
and it just kept going and going
for ten straight months.
And what we saw was
a complete ecological meltdown.
By the time we came back
in March 2016,
almost everything was dead.
It was like a graveyard.
It's just hard to believe that
a whole island can die
in less than a year.
How'd it go? Okay?
Tough, a lot of stuff
going on there.
I want to look at
both of those dive slates
and compare the corals,
photo for all of them,
tissue for all of them,
and growth for some of them.
Yeah.
Okay.
It's pretty devastating,
being down there,
because I just remember
that being my favorite site,
and it just feels,
like, how did this happen?
And even though, obviously,
intellectually
I know exactly what happened,
but emotionally
it still feels like...
it's just really, um...
it's a pretty sad remnant
of what it was.
It's gone, really.
Tropical reefs around the globe
were severely impacted
by the deadly ocean heatwave.
And scientists have been
mobilizing...
led by the Hawaii Institute
of Marine Biology...
a research station
perched on an island
surrounded by coral reef.
Guiding this enormous effort
is visionary scientist
Ruth Gates.
You have a couple of options:
you move, you adapt, or you die.
Obviously corals are dying,
they can't move,
so their only option is
to adapt.
Corals have a natural ability
to adapt to changes
in their environment
and have done so
for millions of years.
But now,
the oceans
are heating up too fast.
So, can we help them?
Can we accelerate
natural selection?
Can we accelerate
adaptive rates?
Ruth is a revolutionary thinker
in a new area of coral science.
It's called assisted evolution.
It is our responsibility to
take our science
and activate things
that can make a difference,
try to solve the problem
instead of just
describe that it exists.
And to take a closer look at
the problems corals are facing,
researchers use
a powerful laser microscope
to generate
images of living corals.
Fluorescence highlights
the algae partners in red.
This is a most beautiful coral.
It's completely healthy,
it's showing,
it's extending its polyps
away from the skeleton.
Kind of out there, waving.
It's just dynamic and beautiful.
Each polyp looks like it's got
a different personality
and it's blowing me a kiss.
It's this one
that's blowing me a kiss.
But what happens to
the symbiotic algae
when waters warm?
This is actually a
partially bleached coral.
It's starting to
lose its symbionts.
You can see
there's a lot more black space
in between the corals.
When heat stresses the corals,
they expel their algae.
These dots of red are
the plant cells
that the animal has
essentially spat out.
They're no longer
serving the animal.
It's no longer moving
anywhere near as dynamically.
It's kind of gone very quiet.
Without the algae,
corals lose their color.
And this is coral bleaching.
Alannah Vellacott is a diver
and coral restoration specialist
who understands this problem
firsthand.
They can always use
a bit of fanning.
Oh, sorry, buddy.
I keep knocking you.
Alannah works at Coral Vita,
a coral farm in the Bahamas
that grows corals
to revitalize dying reefs.
Currently, 80 percent of corals
are dead in the Caribbean.
That is especially sad
and especially troubling
because we cannot afford
to lose our coral reefs.
Reefs are highly diverse
ecosystems.
Fish shelter, find food,
and rear their young
in their many
nooks and crannies.
Fewer reefs means fewer fish,
but it's not just the marine
ecosystem that's at risk.
People depend on reefs for
food and income.
Bahamians are very intimately
tied to our waters,
because it is our livelihood.
Whether you work in a hotel,
whether you're a dive operator,
whether you're a fisherman,
whether you just enjoy
having a conch snack
at the end of the day,
we all depend on these
coral reefs.
If the world continues
to go in the direction
that it's going in,
ignoring what our reefs are
trying to tell us,
it very well is
the end of our livelihoods
here in the Bahamas.
Bahamas and beyond,
some three billion people
rely on fish as
a source of protein,
and the overall
economic value of reefs
is estimated at tens of billions
of dollars annually.
Almost 90 percent of the corals
surrounding Christmas Island
bleached,
and Julia wonders if the reef
and the biodiverse habitat
it provides
could be lost.
Okay, so I have 2015 loaded.
Mm-hmm.
This is just five months before
the heat stress started to hit.
So, the reef is looking
really healthy.
So then let's load the 2017
on top of that
and take a look at
that one overlaid.
Kind of shows how much
the structure is breaking down.
Just...
All the height is eroding.
Devoid of living corals,
the reef is crumbling
and falling apart.
Oh, God, this is horrible.
Can a damaged reef regenerate?
Each year, Julia's team anchors
new clay tiles to the reef
and retrieves tiles
from previous years.
Normally, baby corals
will settle on these,
and the team will document
any signs of new growth.
It feels like a
waiting game to see...
is this gonna turn the corner
and recover,
or is it gonna decline and die?
I still need the white light
to look at it though.
We have a baby coral from
one of the degraded sites.
We hoped for it,
but we didn't really expect it.
So, yeah, that's exciting.
This first evidence of new life
is a tentative sign of
regeneration.
But how could this happen?
After bleaching,
researchers feared
the reef was lost.
In the midst of
all this devastation,
we found a glimmer of hope.
Julia discovered life
among the ruins...
baby corals struggling
to rebuild.
This meant some of the parent
corals withstood the heat.
The corals here had been
sitting in essentially a
hot water bath for ten months,
so they had been stressed out
more than any coral
on the planet,
and yet, here they were,
looking perfectly healthy.
Here, while water temperatures
remained high,
a small percentage of the corals
recovered,
making these the only corals
ever observed
to have been exposed to such
extreme temperatures
for so long and survive.
So, to me, this was
almost like a miracle.
What is it that's so special,
that's so unique
about these corals
that healed themselves
while they were still
under stress.
What is it about them?
Why do some corals survive
when others perish?
What is the secret of
these super corals?
And what can we learn from these
survivors to help save the rest?
Traffic, traffic.
Greg Asner's
Airborne Observatory
is a custom-designed plane
equipped to create a picture
of how reefs are changing.
How many passes through here?
We're going to do...
five more.
Using a spectrometer
and LiDAR lasers,
Greg can analyze the corals
from above,
measure their chemistry,
and create a 3D image.
This region here, in the pinks,
that's the live coral.
These corals are
all a mix of dead and live.
The system gives us a very
unique view of coral reefs,
an understanding of where
the live coral is located.
That's really critical,
especially nowadays
where we're looking
for surviving corals
in literally... in a sea of
a lot of dead coral.
Yeah, we're over
the big island now.
Like many other reefs,
they've gone through
a lot of change.
The burning of fossil fuels
has increased the concentration
of atmospheric carbon dioxide,
raising the Earth's
overall average temperature.
You raise the total temperature
of the planet
and you've changed literally
the fundamental heat flow
over the earth's surface.
You're causing heat waves
in the oceans.
You're causing droughts on land.
You're causing a rebalancing of
the entire thermal portfolio
or profile of
the earth's system,
and that's the thing that we're
dealing with as biologists.
These changes may have
deadly consequences.
So Greg is taking his airborne
research one step further...
teaming up with Ruth Gates
to find corals that
are resistant to bleaching.
We're going to be
getting in the water
to look at the corals that
we flew over yesterday.
And this is key for
linking the aircraft data
to what's going on
in the coral itself.
That's how we make
the connection.
Underwater, Greg will use
a small spectrometer
specifically designed
for diving.
Tools in hand, Ruth and Greg
set out to find
the specific corals identified
by the airborne observatory
as survivors of heat stress.
They need to confirm
that the data from the plane
reflects the reality
on the reef.
By monitoring the reef
over several years,
Ruth has already identified
corals that have
resisted bleaching.
And sure enough,
Greg's spectral
data from the air
matches Ruth's
observations underwater,
bringing them one step closer
to identifying super corals
at a scale and speed
previously unimaginable.
So, the dark brown coral
in the bucket right now,
we affectionately term
"super corals,"
and we call them that because
they are unaffected by
the conditions or the stress
that is causing other corals
immediately adjacent to them
to pale and whiten
and show signs of
very severe stress.
So once we can understand
what is different
between the super corals
and the weak corals,
our goal is to develop
or breed more super corals
that we can use to
restore damaged reefs.
Now Ruth's team prepares
to breed the super corals
that have survived
bleaching events.
Corals here are spawning tonight
and researchers will
act as matchmakers.
If we've got
a really good performer
over here and over here,
let's not leave it to chance
that their
eggs and sperm would meet.
Let's bring them together
and make sure they do.
So that's accelerating
a natural process,
really having
a slight human intervention
to make sure we breed
the best moving forward.
As night falls,
Ruth's team prepares
for one of the most phenomenal
events in all of nature.
Each coral species spawns
at a very specific moment,
timed with seasonal
temperatures and the moon.
Corals can sense the moon,
and they will release
their eggs and sperm
within five minutes
of a particular phase
of the moon,
it's an astonishing thing.
Once spawning begins,
it won't last long.
Researchers use red lights,
so they won't disturb
the corals' ability
to sense lunar cues.
Then move it across...
The team must work quickly
to collect
the precious sperm and eggs.
An entire year's work
is on the line.
Corals are fixed in place,
so they release
gamete bundles containing
their egg and sperm
into the water column.
These buoyant bundles
rise towards the surface,
creating an underwater blizzard
where fertilization begins.
The gametes from selected coral
are caught in the nets.
Lids secured,
researchers
head back to the boat.
Yeah, we have everything!
The team combines
the coral gametes
according to
a predetermined plan,
breeding them for
their strengths.
Time will tell if
tonight's efforts were
successful,
but past years of collecting,
breeding, and observation
have already paid off,
as lab-reared "super corals"
can tolerate
warmer temperatures.
How do we move the needle
and scale to
many different places?
Because the corals
that do well in Hawaii
don't all live, say,
in the Great Barrier Reef.
In Australia, hopes are high
that assisted evolution
could help save
one of the seven natural wonders
of the world.
The Great Barrier Reef
has been hit hard by
successive ocean heat waves,
resulting in
severely bleached coral
along its entire
1,400-mile length.
Researchers here are taking
the next big step,
moving assisted evolution
out of the lab
and into the ocean.
And there is no better place
to prepare super corals
for this journey
than in the state-of-the-art
National Sea Simulator.
Here, Ruth Gates'
long-time collaborator,
ecological geneticist
Madeleine van Oppen,
is soon to embark on
a groundbreaking trial.
Ruth and I met,
I think maybe 2005.
I think the idea
was already starting to happen
that we should use the knowledge
that we had gained
over the past decades
on how corals
adapt and acclimatize,
to actually harness
those mechanisms
to help corals evolve further.
Researchers here can set the
temperature and acidity levels
of individual aquariums
to match those predicted
for the ocean
in the years ahead.
And Madeleine is creating a new
kind of super coral:
a hybrid.
A hybrid is a cross between
two entirely different species.
Hybridization does
happen in nature,
in corals and also in
other plants and animals,
but it doesn't happen
frequently.
When it does, hybrids have
proven to be more resilient.
This is a hybrid coral
that we've actually
created in the lab in 2015,
and actually we put it through
seven months of exposure
to future ocean conditions,
so warmer
and more acidified oceans,
and it survived those
conditions.
Now that Madeleine has
achieved success
with lab-reared hybrids,
she needs to find out
if newborn hybrids can grow and
survive in real ocean waters.
To create these new hybrids,
Madeleine needs eggs
from one species
and sperm from another.
There is no better time
to gather these ingredients
than when corals spawn.
So, this cup is full of the
bundles of eggs and sperm
that are collected outside which
I will now pour over this mesh.
And the mesh is of a size that
the sperm will go through,
and the eggs will stay on top.
With egg and sperm
from two selected
coral species separated,
Madeleine can now bring these
together to create the hybrid.
Even though we have
a fabulous sea simulator,
it still is an aquarium
and it's not exactly
the natural environment,
so we need to test
those results,
validate those results
in the field.
For the first time ever,
these babies are headed
to the Great Barrier Reef.
The biggest challenge is the
really high mortality
we tend to see in the field.
These lab-reared babies
have never experienced
real ocean waters before,
and the transition could
be deadly.
We might get a cyclone that all
of a sudden
pulls down the water,
or we might get
a lot of cloud formation
during summer
that will reduce the amount
of light.
The baby corals grow on tiles
and are transported on trays
to a designated site
alongside the reef.
We really need to have these
field results before
the regulators will allow us
to actually implement these
interventions
in reef restoration.
After three months,
scientists from Madeleine's lab
oversee the infant hybrids'
first checkup.
So, right now we're
cleaning the tiles,
which we just brought up
from the ocean,
so that they'll be ready
for the photographer
to get a clean shot of.
I'm just going through
each tile,
trying to find the babies,
which are still quite small,
they're kind of,
adolescents,
I guess you could say now,
about six months old,
and so we just find them,
and then I circle them,
we take a photo, and that
allows us to look at survival,
and then it also allows
us to measure growth.
There are more than
a thousand tiles
with different genetic
combinations.
It will take over a week
to examine and photograph
every one individually.
So we've just taken all these
photos outside,
so now we're going to start
analyzing them,
and the first thing we do
is just look at alive or dead.
Yeah, so no...
No pencil marks on this one.
Maybe try the next one?
I don't see anything
on that one,
some dead ones, yeah, long dead.
Yeah.
A lot of dead guys.
Early observations
are concerning.
Many of the baby hybrids did not
survive the journey
from lab to sea.
But hope is not lost.
There are more tiles to examine
in the week ahead.
Climate change has affected the
Great Barrier Reef
quite dramatically
in recent years.
We lost half
of the coral present.
As soon as populations start
to lose genetic diversity,
the capacity to adapt further
and respond
to environmental change
also diminishes.
It can become a downward spiral
very, very quickly.
Let's think about
how we actually react
instead of just watching our
system die before our eyes
and then asking ourselves
20 years from now,
"God, I really wish
I'd done something."
During the filming
of this documentary,
Ruth Gates is diagnosed
with brain cancer.
Like the coral reef she loves,
her life hangs in the balance.
Laetitia Hedouin is a scientist
who studied under Ruth Gates.
On the island of Mo'orea
in French Polynesia,
Laetitia is "conditioning"
or "training" corals
to survive ocean heat waves.
Her recent graduates are growing
in this coral nursery.
Laetitia aims to train large
quantities of corals
to make them more resilient.
So her work begins in the
crucial first hours
of a coral's life.
Laetitia will expose these
coral embryos
to increasing amounts of
heat stress.
Like young athletes
on a treadmill,
they will be conditioned
to become "super."
The goal is to increase their
thermal tolerance by subjecting
them to an exercise regime
similar to what they may
experience
in an ocean heat wave.
The embryos have grown quickly
into tiny larvae.
This is the only time
in a coral's life
that it will ever swim.
Once settled, the coral polyp
begins to grow.
Soon it should be moved
to the coral nursery
in Mo'orea's lagoon.
But now, Laetitia finds trouble
brewing on the reef.
An impending ocean heatwave
threatens the reef,
and her research.
As the summer heat intensifies,
so do warnings from the
Intergovernmental Panel
on Climate Change.
About 1900 to present,
that basically represents
a degree Celsius of warming.
With one and a half degrees,
70 to 90 percent of coral reefs
are lost,
but at two it's virtually
all of them.
It's very clear
that half a degree matters.
I think this report is alarming,
it should make us act.
IPCC and other reports now
coming out
are just getting to the level
where they're saying,
"Look, this is happening faster
and, and more extreme
than we thought."
The urgency of this cannot
be overstated.
The changes are real,
the changes are rapid,
and they can be quite extreme.
And if we lose reefs, there
will be dramatic consequences.
Coral reefs provide safe harbor
for our coastlines.
They buffer waves,
helping to prevent erosion,
property damage,
and loss of life.
So, if you look out just in
front of the horizon,
there's a line there, a line of,
of,
of waves, a line of foam,
and that is the reef crest,
and that
is our first line of defense
when it comes to storms
and hurricanes.
When natural ecosystems
that protect coastlines
are in poor condition,
people are vulnerable.
When Hurricane Dorian hit,
it was the worst tropical
cyclone on record
to reach the Bahamas.
The damage was catastrophic.
So, September last year,
the islands of Abaco
and Grand Bahama were absolutely
devastated by Hurricane Dorian.
Sixty percent of Grand Bahama
was underwater,
and thousands and thousands
of people lost their homes.
Hundreds of people are
still missing today.
My childhood home where my dad
lives was completely destroyed.
For the first time I experienced
what it was like
to be a climate change refugee.
And as much as we'd like to
think
of climate change refugees
as people of the future,
the future is today.
It's happening right now.
And what happened in the Bahamas
could happen to coastal
communities anywhere.
Billions of people live within
60 miles of a coastline.
The east coast of Florida is
lined with coral reefs
that have protected people
here for thousands of years.
But now,
these reefs are crumbling.
The Sustain Laboratory at the
University of Miami
is one of the few places
in the world designed
to measure the impacts of a
Category 5 hurricane.
Here, Andrew Baker and his team
are working to quantify
how corals
mitigate the impacts of
extreme storms.
Is there any wind going on this?
Now there is,
now there is, yeah.
That's pretty good, it's
breaking right on the coral.
Because of climate change,
we're seeing rising seas,
we're seeing more powerful
storms,
we're seeing storm surge
and other kinds of flooding
impacts.
Coral reefs have been shown
to reduce wave energy
in some cases by 94, 95 percent.
Without reefs to protect
its shoreline,
storm surges could
devastate Miami.
How do we make coral reefs
more climate ready,
more climate tolerant,
more thermally tolerant,
and how do we protect
our coastlines
from the damaging effects
of storms?
So, what we're trying to do
is not only use coral reefs
to build natural breakwaters,
but make the very corals
that we're using to build
those reefs
themselves more thermally
tolerant.
Andrew and his team
are trying to make reefs
more climate-ready by helping
corals switch their algae
to ones that can take the heat.
The researchers use a technique
called "controlled bleaching,"
attaching the corals to a raft,
then raising them up toward
the surface
where they'll receive
more sunlight.
After a few hot days under
clear skies,
the coral stress,
eject their algae, and bleach.
And without the nourishment
the algae provide,
the corals will soon die.
But Andrew has a plan to save
them from this fate...
This partnership between the
coral and its algae
dates back over
a hundred million years.
We have different types of
corals,
but we also have many different
types of algae,
and in fact they can sometimes
switch from one type of alga
to another, and that's exactly
what we think
we're seeing under
climate change.
And some of these algae
are more tolerant to heat.
If corals are able
to flexibly associate
with different types of algae,
perhaps they could switch to
these more heat tolerant ones
and that might help
them survive.
Heat-tolerant algae
are less likely
to be expelled by the coral,
and the coral won't bleach.
If the corals bleached
on the raft recover
with heat-tolerant algae,
they may survive the next
ocean heat wave.
And this could be
a big step forward
for assisted evolution.
This is a test... we're hoping
that this is going to be
something that
proves successful,
that is easily scalable,
cost effective, and we can roll
it out and apply it
to the restoration efforts
that are going on
all over the place.
Today, Andrew's team
plants the corals that bleached
on the raft out on the reef.
Standard corals act as
a control group.
We're hoping that the corals
that we've bleached
on these rafts are going
to recover with
different symbionts that we hope
are more thermally tolerant
and that help these corals
resist bleaching in the future.
The corals may now have the
ability to survive bleaching,
and the next ocean heat wave.
But what about the one
after that?
If climate change is
still ongoing past 2100,
then nothing we're doing
is going to help solve that.
Ultimately, we have to get
carbon emissions under control
and try to prevent
this runaway warming event.
And in the midst of this
planetary crisis,
coral scientists receive
devastating news.
At age 56, Ruth Gates, pioneer
of assisted evolution, dies.
Yeah, it's difficult to talk
about it, but, um...
I just, it's so hard to believe
that she's gone, right?
Ruth was a very inspiring
person.
She was always smiling
and laughing, and...
and so I think, um...
yeah, sorry.
She always find a good word
and, and the time to be here
when you need it.
I think that I, I've never
laughed so much, um,
doing science than I have
with Ruth Gates.
It was, we had a great time,
and to lose her,
it's like a huge piece of the,
of the science machine,
but also the leadership machine
just disappeared.
What she did do was instill
so much spirit
and motivation to keep going.
We wanted to really send out
the message
that assisted evolution is an
important approach to explore,
and Ruth, of course,
played a very big role
in sending that message out
across the world and I think
we have succeeded.
We've been able to convince
the community
that this is important.
When Madeleine van Oppen's team
first checked
the experimental hybrids,
the results were discouraging.
But they didn't give up.
There it is.
I knew it was on here, I saw it.
Tiny young corals are alive
on the tiles,
signs that these
heartier hybrids are surviving
life outside the lab,
a first for the team.
Well, we still have to take
a good look at the data,
but we're seeing corals popping
up here and there.
Is Grant gonna take it down?
They're gonna take them back out
onto the reef,
and we'll be keeping those guys
out there for another
few months until we check up on
them again in October.
Back at the sea simulator,
researchers share their
documentation with Madeleine.
I see some kind of...
Yes, it looks like there's
some structure still there,
rather than the whole, isn't it?
And it's smooth texture.
That is clean.
That one is quite pale,
isn't it?
Yeah.
I saw a lot of variability
in color.
When we first bred coral
recruits in the sea simulator
five years ago, everything died
between Christmas and New Year.
We had a huge effort, and then
the year after we had
a little bit longer survival,
and so we learned as we went.
These are the baby steps
that we have made,
but small steps in
the right direction.
It gives me hope and I just pray
that it's gonna be enough.
Assisted evolution is now
a growing movement
around the globe.
Scientists are finding
successful solutions
that might give corals
the chance they need
to make it through
the coming decades.
Coral Vita is expanding its
farming operations
beyond the Bahamas,
aiming to provide
resilient corals to reef rescue
operations worldwide.
We can make choices
to help our environment,
to help our coral reefs,
to bring them back to life.
We are growing corals to be more
resilient to the effects
that climate change is having
on our oceans.
Super corals tested and planted
by the Gates Coral Lab
are now being used to restore
the protective reef around Oahu.
Andrew Baker's corals bleached
and recovered,
but did not switch
to the heat-tolerant algae.
However, back in the lab,
different species have
successfully made the swap
and are now being planted
on reefs off Miami to see
if these corals remain resilient
in warming ocean waters.
Julia Baum discovered that
the corals that survived
the mass bleaching
on Christmas Island did
so because
they switched to a heat-tolerant
algae naturally.
Tragically,
the reefs around the island
of Mo'orea
experienced a massive
ocean heat wave.
Fifty percent of the corals
raised in the nursery perished.
But those that made it proved
their resilience and
Laetitia Hedouin is optimistic
that she will learn from
the survivors.
We need to know more, so we
can harness that knowledge.
I mean, what could be better
than that?
Being a part of a solution
that will help the world.
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the human imagination
for as long as we have
ventured beneath the waves.
Towering, romantic, strong,
resilient,
but very ornate and,
and delicate at the same time.
There really is
nothing else like it.
Beyond their beauty
and brilliance,
coral reefs support
a quarter of all marine life
and are crucial for ocean health
and human survival.
But now these precious creatures
are in crisis,
as ocean heat waves
are bleaching corals
of all color and life.
By the end of this century,
coral reefs could be lost.
Can we help them?
Can we accelerate
natural selection?
Can we accelerate
adaptive rates?
On tropical reefs around
the globe,
scientists are fighting
a desperate race against time.
Unlocking the secrets of
millions of years
of coral evolution
and trying to speed it up.
If we are going to save
coral reefs,
we have to start intervening.
Their ideas are new
and experimental.
And for the first time,
their daring research
will be put to the test.
I think science and scientists
are being asked to
solve problems.
Honestly, we don't know
whether it's going to work.
The risk of doing nothing
is the risk of
risking every reef
on the planet.
"Reef Rescue,"
right now on "NOVA."
I will often describe it as
my cathedral.
If you could imagine a cathedral
with all of the
stained-glass windows,
all of that color is
splashed across the landscape,
with the fish
darting in and out.
It's the place I go
where I feel awed
by the complexity of
the architecture around me.
Coral reefs have been compared
to tropical rainforests,
and what I mean by that is
the diversity of the species and
how they're packed in together,
how they create
this kaleidoscope
of color and function.
When I go underwater,
each coral head
is like its own little city.
When you get to a
massive spur and groove system,
it's like downtown Atlanta,
super busy, bustling,
characters everywhere,
different sounds,
clicking and popping
and bubbling.
And it reminds you
that we are all one piece of
a community, or ecosystem.
Corals appeared
500 million years ago.
They may look like rocks,
but corals are in fact animals.
Each tiny coral creature
is called a polyp.
The polyp is essentially
a mouth with tentacles
used to trap floating food,
but most corals also have
another source of nourishment.
Inside the cells of the animal,
there is a tiny plant cell
and they, as all plants do,
are able to use the
energy of the sun, capture it,
to combine carbon dioxide
and water
into a small food molecule
and oxygen.
These microscopic plant-like
organisms are algae.
The algae feed the coral animal,
and the coral
gives the algae a home.
It's a dynamic
symbiotic relationship.
So much so that
the algae are called symbionts.
Reefs begin when coral polyps
secrete a thin layer of
calcium carbonate
to create a skeleton.
Hundreds and hundreds
of identical coral polyps
create a colony.
And over thousands of years
of growth,
coral colonies build the reef.
So animal, vegetable, mineral.
That is what a coral is.
Christmas Island is an atoll
in the Pacific Ocean
made entirely of coral.
Julia Baum is a
Canadian marine biologist.
For more than a decade,
she's studied the reef's
unique ecosystem
and the threats it faces.
It always feels great
to be back.
It's a bit of a mix of emotions;
there's, there's so much
invested in every single trip.
Always a little bit of
excitement
about an adventure
that's about to begin,
and also maybe
a little apprehension
just to make sure,
is everything going to go okay?
Hey!
Hi!
I think that it's actually,
I know it sounds crazy...
And then I think that...
but I think it's actually
you're gonna,
you're gonna drop there.
And that's...
It's Julia's first day out on
the reef this year.
Oh, did you...
The team dives down to
take stock of the coral.
When I first started doing
research on the ocean,
I had been so focused on
sharks and fish,
and at some point,
I think I kind of looked down
and saw the coral and realized,
"Hey, the coral
are the whole foundation
of this ecosystem."
And if we're worried
about this ecosystem,
we really have to be worried
about the coral themselves.
We have hundreds of corals
tagged all around the island,
and we take tiny tissue samples
from them.
We can take the photos
to identify individual
coral colonies themselves
and get a sense of who's there
in the community.
A brain coral is one of
the main types of corals
that we've been working with.
There's also branching corals
and flat corals,
so lots of different shapes,
and those are important
because they provide
different types of habitat
for fishes.
Each year, Julia and her team
meticulously tag,
sample, and photograph
40 plots of coral,
building a timeline of
how the reefs are changing.
During the
2015 and 2016 El Niño,
water temperatures here
increased by
four degrees Fahrenheit.
The heat set itself down
on this island
and just got a chokehold on it,
and it just kept going and going
for ten straight months.
And what we saw was
a complete ecological meltdown.
By the time we came back
in March 2016,
almost everything was dead.
It was like a graveyard.
It's just hard to believe that
a whole island can die
in less than a year.
How'd it go? Okay?
Tough, a lot of stuff
going on there.
I want to look at
both of those dive slates
and compare the corals,
photo for all of them,
tissue for all of them,
and growth for some of them.
Yeah.
Okay.
It's pretty devastating,
being down there,
because I just remember
that being my favorite site,
and it just feels,
like, how did this happen?
And even though, obviously,
intellectually
I know exactly what happened,
but emotionally
it still feels like...
it's just really, um...
it's a pretty sad remnant
of what it was.
It's gone, really.
Tropical reefs around the globe
were severely impacted
by the deadly ocean heatwave.
And scientists have been
mobilizing...
led by the Hawaii Institute
of Marine Biology...
a research station
perched on an island
surrounded by coral reef.
Guiding this enormous effort
is visionary scientist
Ruth Gates.
You have a couple of options:
you move, you adapt, or you die.
Obviously corals are dying,
they can't move,
so their only option is
to adapt.
Corals have a natural ability
to adapt to changes
in their environment
and have done so
for millions of years.
But now,
the oceans
are heating up too fast.
So, can we help them?
Can we accelerate
natural selection?
Can we accelerate
adaptive rates?
Ruth is a revolutionary thinker
in a new area of coral science.
It's called assisted evolution.
It is our responsibility to
take our science
and activate things
that can make a difference,
try to solve the problem
instead of just
describe that it exists.
And to take a closer look at
the problems corals are facing,
researchers use
a powerful laser microscope
to generate
images of living corals.
Fluorescence highlights
the algae partners in red.
This is a most beautiful coral.
It's completely healthy,
it's showing,
it's extending its polyps
away from the skeleton.
Kind of out there, waving.
It's just dynamic and beautiful.
Each polyp looks like it's got
a different personality
and it's blowing me a kiss.
It's this one
that's blowing me a kiss.
But what happens to
the symbiotic algae
when waters warm?
This is actually a
partially bleached coral.
It's starting to
lose its symbionts.
You can see
there's a lot more black space
in between the corals.
When heat stresses the corals,
they expel their algae.
These dots of red are
the plant cells
that the animal has
essentially spat out.
They're no longer
serving the animal.
It's no longer moving
anywhere near as dynamically.
It's kind of gone very quiet.
Without the algae,
corals lose their color.
And this is coral bleaching.
Alannah Vellacott is a diver
and coral restoration specialist
who understands this problem
firsthand.
They can always use
a bit of fanning.
Oh, sorry, buddy.
I keep knocking you.
Alannah works at Coral Vita,
a coral farm in the Bahamas
that grows corals
to revitalize dying reefs.
Currently, 80 percent of corals
are dead in the Caribbean.
That is especially sad
and especially troubling
because we cannot afford
to lose our coral reefs.
Reefs are highly diverse
ecosystems.
Fish shelter, find food,
and rear their young
in their many
nooks and crannies.
Fewer reefs means fewer fish,
but it's not just the marine
ecosystem that's at risk.
People depend on reefs for
food and income.
Bahamians are very intimately
tied to our waters,
because it is our livelihood.
Whether you work in a hotel,
whether you're a dive operator,
whether you're a fisherman,
whether you just enjoy
having a conch snack
at the end of the day,
we all depend on these
coral reefs.
If the world continues
to go in the direction
that it's going in,
ignoring what our reefs are
trying to tell us,
it very well is
the end of our livelihoods
here in the Bahamas.
Bahamas and beyond,
some three billion people
rely on fish as
a source of protein,
and the overall
economic value of reefs
is estimated at tens of billions
of dollars annually.
Almost 90 percent of the corals
surrounding Christmas Island
bleached,
and Julia wonders if the reef
and the biodiverse habitat
it provides
could be lost.
Okay, so I have 2015 loaded.
Mm-hmm.
This is just five months before
the heat stress started to hit.
So, the reef is looking
really healthy.
So then let's load the 2017
on top of that
and take a look at
that one overlaid.
Kind of shows how much
the structure is breaking down.
Just...
All the height is eroding.
Devoid of living corals,
the reef is crumbling
and falling apart.
Oh, God, this is horrible.
Can a damaged reef regenerate?
Each year, Julia's team anchors
new clay tiles to the reef
and retrieves tiles
from previous years.
Normally, baby corals
will settle on these,
and the team will document
any signs of new growth.
It feels like a
waiting game to see...
is this gonna turn the corner
and recover,
or is it gonna decline and die?
I still need the white light
to look at it though.
We have a baby coral from
one of the degraded sites.
We hoped for it,
but we didn't really expect it.
So, yeah, that's exciting.
This first evidence of new life
is a tentative sign of
regeneration.
But how could this happen?
After bleaching,
researchers feared
the reef was lost.
In the midst of
all this devastation,
we found a glimmer of hope.
Julia discovered life
among the ruins...
baby corals struggling
to rebuild.
This meant some of the parent
corals withstood the heat.
The corals here had been
sitting in essentially a
hot water bath for ten months,
so they had been stressed out
more than any coral
on the planet,
and yet, here they were,
looking perfectly healthy.
Here, while water temperatures
remained high,
a small percentage of the corals
recovered,
making these the only corals
ever observed
to have been exposed to such
extreme temperatures
for so long and survive.
So, to me, this was
almost like a miracle.
What is it that's so special,
that's so unique
about these corals
that healed themselves
while they were still
under stress.
What is it about them?
Why do some corals survive
when others perish?
What is the secret of
these super corals?
And what can we learn from these
survivors to help save the rest?
Traffic, traffic.
Greg Asner's
Airborne Observatory
is a custom-designed plane
equipped to create a picture
of how reefs are changing.
How many passes through here?
We're going to do...
five more.
Using a spectrometer
and LiDAR lasers,
Greg can analyze the corals
from above,
measure their chemistry,
and create a 3D image.
This region here, in the pinks,
that's the live coral.
These corals are
all a mix of dead and live.
The system gives us a very
unique view of coral reefs,
an understanding of where
the live coral is located.
That's really critical,
especially nowadays
where we're looking
for surviving corals
in literally... in a sea of
a lot of dead coral.
Yeah, we're over
the big island now.
Like many other reefs,
they've gone through
a lot of change.
The burning of fossil fuels
has increased the concentration
of atmospheric carbon dioxide,
raising the Earth's
overall average temperature.
You raise the total temperature
of the planet
and you've changed literally
the fundamental heat flow
over the earth's surface.
You're causing heat waves
in the oceans.
You're causing droughts on land.
You're causing a rebalancing of
the entire thermal portfolio
or profile of
the earth's system,
and that's the thing that we're
dealing with as biologists.
These changes may have
deadly consequences.
So Greg is taking his airborne
research one step further...
teaming up with Ruth Gates
to find corals that
are resistant to bleaching.
We're going to be
getting in the water
to look at the corals that
we flew over yesterday.
And this is key for
linking the aircraft data
to what's going on
in the coral itself.
That's how we make
the connection.
Underwater, Greg will use
a small spectrometer
specifically designed
for diving.
Tools in hand, Ruth and Greg
set out to find
the specific corals identified
by the airborne observatory
as survivors of heat stress.
They need to confirm
that the data from the plane
reflects the reality
on the reef.
By monitoring the reef
over several years,
Ruth has already identified
corals that have
resisted bleaching.
And sure enough,
Greg's spectral
data from the air
matches Ruth's
observations underwater,
bringing them one step closer
to identifying super corals
at a scale and speed
previously unimaginable.
So, the dark brown coral
in the bucket right now,
we affectionately term
"super corals,"
and we call them that because
they are unaffected by
the conditions or the stress
that is causing other corals
immediately adjacent to them
to pale and whiten
and show signs of
very severe stress.
So once we can understand
what is different
between the super corals
and the weak corals,
our goal is to develop
or breed more super corals
that we can use to
restore damaged reefs.
Now Ruth's team prepares
to breed the super corals
that have survived
bleaching events.
Corals here are spawning tonight
and researchers will
act as matchmakers.
If we've got
a really good performer
over here and over here,
let's not leave it to chance
that their
eggs and sperm would meet.
Let's bring them together
and make sure they do.
So that's accelerating
a natural process,
really having
a slight human intervention
to make sure we breed
the best moving forward.
As night falls,
Ruth's team prepares
for one of the most phenomenal
events in all of nature.
Each coral species spawns
at a very specific moment,
timed with seasonal
temperatures and the moon.
Corals can sense the moon,
and they will release
their eggs and sperm
within five minutes
of a particular phase
of the moon,
it's an astonishing thing.
Once spawning begins,
it won't last long.
Researchers use red lights,
so they won't disturb
the corals' ability
to sense lunar cues.
Then move it across...
The team must work quickly
to collect
the precious sperm and eggs.
An entire year's work
is on the line.
Corals are fixed in place,
so they release
gamete bundles containing
their egg and sperm
into the water column.
These buoyant bundles
rise towards the surface,
creating an underwater blizzard
where fertilization begins.
The gametes from selected coral
are caught in the nets.
Lids secured,
researchers
head back to the boat.
Yeah, we have everything!
The team combines
the coral gametes
according to
a predetermined plan,
breeding them for
their strengths.
Time will tell if
tonight's efforts were
successful,
but past years of collecting,
breeding, and observation
have already paid off,
as lab-reared "super corals"
can tolerate
warmer temperatures.
How do we move the needle
and scale to
many different places?
Because the corals
that do well in Hawaii
don't all live, say,
in the Great Barrier Reef.
In Australia, hopes are high
that assisted evolution
could help save
one of the seven natural wonders
of the world.
The Great Barrier Reef
has been hit hard by
successive ocean heat waves,
resulting in
severely bleached coral
along its entire
1,400-mile length.
Researchers here are taking
the next big step,
moving assisted evolution
out of the lab
and into the ocean.
And there is no better place
to prepare super corals
for this journey
than in the state-of-the-art
National Sea Simulator.
Here, Ruth Gates'
long-time collaborator,
ecological geneticist
Madeleine van Oppen,
is soon to embark on
a groundbreaking trial.
Ruth and I met,
I think maybe 2005.
I think the idea
was already starting to happen
that we should use the knowledge
that we had gained
over the past decades
on how corals
adapt and acclimatize,
to actually harness
those mechanisms
to help corals evolve further.
Researchers here can set the
temperature and acidity levels
of individual aquariums
to match those predicted
for the ocean
in the years ahead.
And Madeleine is creating a new
kind of super coral:
a hybrid.
A hybrid is a cross between
two entirely different species.
Hybridization does
happen in nature,
in corals and also in
other plants and animals,
but it doesn't happen
frequently.
When it does, hybrids have
proven to be more resilient.
This is a hybrid coral
that we've actually
created in the lab in 2015,
and actually we put it through
seven months of exposure
to future ocean conditions,
so warmer
and more acidified oceans,
and it survived those
conditions.
Now that Madeleine has
achieved success
with lab-reared hybrids,
she needs to find out
if newborn hybrids can grow and
survive in real ocean waters.
To create these new hybrids,
Madeleine needs eggs
from one species
and sperm from another.
There is no better time
to gather these ingredients
than when corals spawn.
So, this cup is full of the
bundles of eggs and sperm
that are collected outside which
I will now pour over this mesh.
And the mesh is of a size that
the sperm will go through,
and the eggs will stay on top.
With egg and sperm
from two selected
coral species separated,
Madeleine can now bring these
together to create the hybrid.
Even though we have
a fabulous sea simulator,
it still is an aquarium
and it's not exactly
the natural environment,
so we need to test
those results,
validate those results
in the field.
For the first time ever,
these babies are headed
to the Great Barrier Reef.
The biggest challenge is the
really high mortality
we tend to see in the field.
These lab-reared babies
have never experienced
real ocean waters before,
and the transition could
be deadly.
We might get a cyclone that all
of a sudden
pulls down the water,
or we might get
a lot of cloud formation
during summer
that will reduce the amount
of light.
The baby corals grow on tiles
and are transported on trays
to a designated site
alongside the reef.
We really need to have these
field results before
the regulators will allow us
to actually implement these
interventions
in reef restoration.
After three months,
scientists from Madeleine's lab
oversee the infant hybrids'
first checkup.
So, right now we're
cleaning the tiles,
which we just brought up
from the ocean,
so that they'll be ready
for the photographer
to get a clean shot of.
I'm just going through
each tile,
trying to find the babies,
which are still quite small,
they're kind of,
adolescents,
I guess you could say now,
about six months old,
and so we just find them,
and then I circle them,
we take a photo, and that
allows us to look at survival,
and then it also allows
us to measure growth.
There are more than
a thousand tiles
with different genetic
combinations.
It will take over a week
to examine and photograph
every one individually.
So we've just taken all these
photos outside,
so now we're going to start
analyzing them,
and the first thing we do
is just look at alive or dead.
Yeah, so no...
No pencil marks on this one.
Maybe try the next one?
I don't see anything
on that one,
some dead ones, yeah, long dead.
Yeah.
A lot of dead guys.
Early observations
are concerning.
Many of the baby hybrids did not
survive the journey
from lab to sea.
But hope is not lost.
There are more tiles to examine
in the week ahead.
Climate change has affected the
Great Barrier Reef
quite dramatically
in recent years.
We lost half
of the coral present.
As soon as populations start
to lose genetic diversity,
the capacity to adapt further
and respond
to environmental change
also diminishes.
It can become a downward spiral
very, very quickly.
Let's think about
how we actually react
instead of just watching our
system die before our eyes
and then asking ourselves
20 years from now,
"God, I really wish
I'd done something."
During the filming
of this documentary,
Ruth Gates is diagnosed
with brain cancer.
Like the coral reef she loves,
her life hangs in the balance.
Laetitia Hedouin is a scientist
who studied under Ruth Gates.
On the island of Mo'orea
in French Polynesia,
Laetitia is "conditioning"
or "training" corals
to survive ocean heat waves.
Her recent graduates are growing
in this coral nursery.
Laetitia aims to train large
quantities of corals
to make them more resilient.
So her work begins in the
crucial first hours
of a coral's life.
Laetitia will expose these
coral embryos
to increasing amounts of
heat stress.
Like young athletes
on a treadmill,
they will be conditioned
to become "super."
The goal is to increase their
thermal tolerance by subjecting
them to an exercise regime
similar to what they may
experience
in an ocean heat wave.
The embryos have grown quickly
into tiny larvae.
This is the only time
in a coral's life
that it will ever swim.
Once settled, the coral polyp
begins to grow.
Soon it should be moved
to the coral nursery
in Mo'orea's lagoon.
But now, Laetitia finds trouble
brewing on the reef.
An impending ocean heatwave
threatens the reef,
and her research.
As the summer heat intensifies,
so do warnings from the
Intergovernmental Panel
on Climate Change.
About 1900 to present,
that basically represents
a degree Celsius of warming.
With one and a half degrees,
70 to 90 percent of coral reefs
are lost,
but at two it's virtually
all of them.
It's very clear
that half a degree matters.
I think this report is alarming,
it should make us act.
IPCC and other reports now
coming out
are just getting to the level
where they're saying,
"Look, this is happening faster
and, and more extreme
than we thought."
The urgency of this cannot
be overstated.
The changes are real,
the changes are rapid,
and they can be quite extreme.
And if we lose reefs, there
will be dramatic consequences.
Coral reefs provide safe harbor
for our coastlines.
They buffer waves,
helping to prevent erosion,
property damage,
and loss of life.
So, if you look out just in
front of the horizon,
there's a line there, a line of,
of,
of waves, a line of foam,
and that is the reef crest,
and that
is our first line of defense
when it comes to storms
and hurricanes.
When natural ecosystems
that protect coastlines
are in poor condition,
people are vulnerable.
When Hurricane Dorian hit,
it was the worst tropical
cyclone on record
to reach the Bahamas.
The damage was catastrophic.
So, September last year,
the islands of Abaco
and Grand Bahama were absolutely
devastated by Hurricane Dorian.
Sixty percent of Grand Bahama
was underwater,
and thousands and thousands
of people lost their homes.
Hundreds of people are
still missing today.
My childhood home where my dad
lives was completely destroyed.
For the first time I experienced
what it was like
to be a climate change refugee.
And as much as we'd like to
think
of climate change refugees
as people of the future,
the future is today.
It's happening right now.
And what happened in the Bahamas
could happen to coastal
communities anywhere.
Billions of people live within
60 miles of a coastline.
The east coast of Florida is
lined with coral reefs
that have protected people
here for thousands of years.
But now,
these reefs are crumbling.
The Sustain Laboratory at the
University of Miami
is one of the few places
in the world designed
to measure the impacts of a
Category 5 hurricane.
Here, Andrew Baker and his team
are working to quantify
how corals
mitigate the impacts of
extreme storms.
Is there any wind going on this?
Now there is,
now there is, yeah.
That's pretty good, it's
breaking right on the coral.
Because of climate change,
we're seeing rising seas,
we're seeing more powerful
storms,
we're seeing storm surge
and other kinds of flooding
impacts.
Coral reefs have been shown
to reduce wave energy
in some cases by 94, 95 percent.
Without reefs to protect
its shoreline,
storm surges could
devastate Miami.
How do we make coral reefs
more climate ready,
more climate tolerant,
more thermally tolerant,
and how do we protect
our coastlines
from the damaging effects
of storms?
So, what we're trying to do
is not only use coral reefs
to build natural breakwaters,
but make the very corals
that we're using to build
those reefs
themselves more thermally
tolerant.
Andrew and his team
are trying to make reefs
more climate-ready by helping
corals switch their algae
to ones that can take the heat.
The researchers use a technique
called "controlled bleaching,"
attaching the corals to a raft,
then raising them up toward
the surface
where they'll receive
more sunlight.
After a few hot days under
clear skies,
the coral stress,
eject their algae, and bleach.
And without the nourishment
the algae provide,
the corals will soon die.
But Andrew has a plan to save
them from this fate...
This partnership between the
coral and its algae
dates back over
a hundred million years.
We have different types of
corals,
but we also have many different
types of algae,
and in fact they can sometimes
switch from one type of alga
to another, and that's exactly
what we think
we're seeing under
climate change.
And some of these algae
are more tolerant to heat.
If corals are able
to flexibly associate
with different types of algae,
perhaps they could switch to
these more heat tolerant ones
and that might help
them survive.
Heat-tolerant algae
are less likely
to be expelled by the coral,
and the coral won't bleach.
If the corals bleached
on the raft recover
with heat-tolerant algae,
they may survive the next
ocean heat wave.
And this could be
a big step forward
for assisted evolution.
This is a test... we're hoping
that this is going to be
something that
proves successful,
that is easily scalable,
cost effective, and we can roll
it out and apply it
to the restoration efforts
that are going on
all over the place.
Today, Andrew's team
plants the corals that bleached
on the raft out on the reef.
Standard corals act as
a control group.
We're hoping that the corals
that we've bleached
on these rafts are going
to recover with
different symbionts that we hope
are more thermally tolerant
and that help these corals
resist bleaching in the future.
The corals may now have the
ability to survive bleaching,
and the next ocean heat wave.
But what about the one
after that?
If climate change is
still ongoing past 2100,
then nothing we're doing
is going to help solve that.
Ultimately, we have to get
carbon emissions under control
and try to prevent
this runaway warming event.
And in the midst of this
planetary crisis,
coral scientists receive
devastating news.
At age 56, Ruth Gates, pioneer
of assisted evolution, dies.
Yeah, it's difficult to talk
about it, but, um...
I just, it's so hard to believe
that she's gone, right?
Ruth was a very inspiring
person.
She was always smiling
and laughing, and...
and so I think, um...
yeah, sorry.
She always find a good word
and, and the time to be here
when you need it.
I think that I, I've never
laughed so much, um,
doing science than I have
with Ruth Gates.
It was, we had a great time,
and to lose her,
it's like a huge piece of the,
of the science machine,
but also the leadership machine
just disappeared.
What she did do was instill
so much spirit
and motivation to keep going.
We wanted to really send out
the message
that assisted evolution is an
important approach to explore,
and Ruth, of course,
played a very big role
in sending that message out
across the world and I think
we have succeeded.
We've been able to convince
the community
that this is important.
When Madeleine van Oppen's team
first checked
the experimental hybrids,
the results were discouraging.
But they didn't give up.
There it is.
I knew it was on here, I saw it.
Tiny young corals are alive
on the tiles,
signs that these
heartier hybrids are surviving
life outside the lab,
a first for the team.
Well, we still have to take
a good look at the data,
but we're seeing corals popping
up here and there.
Is Grant gonna take it down?
They're gonna take them back out
onto the reef,
and we'll be keeping those guys
out there for another
few months until we check up on
them again in October.
Back at the sea simulator,
researchers share their
documentation with Madeleine.
I see some kind of...
Yes, it looks like there's
some structure still there,
rather than the whole, isn't it?
And it's smooth texture.
That is clean.
That one is quite pale,
isn't it?
Yeah.
I saw a lot of variability
in color.
When we first bred coral
recruits in the sea simulator
five years ago, everything died
between Christmas and New Year.
We had a huge effort, and then
the year after we had
a little bit longer survival,
and so we learned as we went.
These are the baby steps
that we have made,
but small steps in
the right direction.
It gives me hope and I just pray
that it's gonna be enough.
Assisted evolution is now
a growing movement
around the globe.
Scientists are finding
successful solutions
that might give corals
the chance they need
to make it through
the coming decades.
Coral Vita is expanding its
farming operations
beyond the Bahamas,
aiming to provide
resilient corals to reef rescue
operations worldwide.
We can make choices
to help our environment,
to help our coral reefs,
to bring them back to life.
We are growing corals to be more
resilient to the effects
that climate change is having
on our oceans.
Super corals tested and planted
by the Gates Coral Lab
are now being used to restore
the protective reef around Oahu.
Andrew Baker's corals bleached
and recovered,
but did not switch
to the heat-tolerant algae.
However, back in the lab,
different species have
successfully made the swap
and are now being planted
on reefs off Miami to see
if these corals remain resilient
in warming ocean waters.
Julia Baum discovered that
the corals that survived
the mass bleaching
on Christmas Island did
so because
they switched to a heat-tolerant
algae naturally.
Tragically,
the reefs around the island
of Mo'orea
experienced a massive
ocean heat wave.
Fifty percent of the corals
raised in the nursery perished.
But those that made it proved
their resilience and
Laetitia Hedouin is optimistic
that she will learn from
the survivors.
We need to know more, so we
can harness that knowledge.
I mean, what could be better
than that?
Being a part of a solution
that will help the world.
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