NICK SCHIFRIN: Coral reefs
around the world are in
growing danger, due in no
small part to rising
temperatures connected
with climate change.
But, in Florida and throughout
the Caribbean, there is now a
new mysterious epidemic killing
once healthy corals.
Scientists are diving
deep to find some answers.
And science correspondent
Miles O'Brien recently
joined them on their
mission to revive the reefs.
MILES O'BRIEN:
I have been scuba diving
in Florida and the
Bahamas for 35 years,
which makes me an eyewitness
to a slow-motion disaster.
Marine biologist Karen Neely is
also saddened by what she sees.
KAREN NEELY, Nova Southeastern
University: I know what it's
like to go somewhere where
you have had old friends
and they're not there
anymore. That's what
we're seeing on the reefs
here. Over the last 20
years, there's just been
the continued loss of coral.
MILES O'BRIEN: It's a
global problem brought on
by pollution, overfishing
and the climate crisis.
The Intergovernmental
Panel on Climate Change
predicts up to 90 percent of
tropical coral reefs will
vanish as soon as 2030 unless
drastic action is taken to limit
greenhouse gases. Grim
as that is, here in
Florida, things are worse.
Neely is on a mission to stop a
deadly coral epidemic decimating
reefs here and throughout the
Caribbean. First identified
near Miami in 2014,
stony coral tissue loss
decide spreads and kills
like wildfire. It strikes
more than 20 of the 60
or so species of coral
that live here. Mortality
rates range from 66 to 100
percent. The iconic Pillar coral
is one of the most susceptible.
VALERIE PAUL, Director,
Smithsonian Marine Station at
Fort Pierce: It's heartbreaking.
It's just unbelievable.
MILES O'BRIEN: Marine
biologist Valerie Paul
is head scientist at the
Smithsonian Marine Station
at Fort Pierce. She's
helping lead the urgent
hunt for answers.
VALERIE PAUL: When we started,
we didn't know anything.
We just knew it was killing
coral tissue, right? We
know more than we did
a few years ago, but we
surely don't know enough.
MILES O'BRIEN: Corals are
complex, fragile, and poorly
understood animals. They survive
thanks to a mutually beneficial
or symbiotic relationship with
algae that live in coral tissue.
In this marriage, the coral
is the homemaker and the
algae brings home the bacon,
actually, nutrients derived
from photosynthesis.
Many of the vivid colors
of coral are actually
created by the algae.
So, white patches are
signs disease or death.
VALERIE PAUL: So really, this
whole piece is diseased at this
stage. This is fairly advanced
disease on this coral.
MILES O'BRIEN: But no
one know what is sort
of pathogen is at work.
It could be viral or bacterial
or perhaps some combination.
Here, they isolated a
beneficial bacterium that
fights offs the disease.
VALERIE PAUL: We started
just testing it in the
laboratory first in various
aquarium studies with
pieces of diseased coral
and saw that it would
slow down the disease
or stop it entirely. So this
was like, wow, this is cool.
MILES O'BRIEN: So they are
treating healthy corals with
probiotics applied beneath a
weighted bag. It looks
promising, but it's still early.
Antibiotics are also working.
Karen Neely is part of a
small team of researchers
applying amoxicillin
paste to ailing corals.
KAREN NEELY: We can come
back in a month, and that
coral has no sign of disease,
it's not dying anymore.
And, eventually, it
starts re growing.
MILES O'BRIEN: Her team
from Nova Southeastern
University and others
have collectively saved
nearly 15,000 corals.
Still, the researchers are well
aware they're only making a
small dent in a massive problem.
KAREN NEELY: We really
have to be quite selective.
We're figuring out,
what can we save, what might
be OK if we can't get to it,
and what are we going to lose
regardless, and trying to get
the most bang for the buck?
We can't just pretend
this isn't happening and
not do anything about it,
or the prognosis takes a
sharp turn for the worse.
MILES O'BRIEN: At the
Florida Aquarium Coral
Conservation Center near Tampa,
they are fighting
this disease on land.
KERI O'NEIL, Florida Aquarium
Coral Conservation Center: So,
this is a tank of corals
that are going out into the
ocean in a couple of weeks.
MILES O'BRIEN: Keri O'Neil is
the senior coral scientist here.
At first, she hoped to
participate in a massive effort
by a team of scientists to
harvest healthy coral
from the reefs to create
an ark, a desperate move
to avoid extinctions.
KERI O'NEIL: However, they
don't stop growing. And
if you're keeping them
under happy conditions,
then they're just going to
keep growing and growing.
MILES O'BRIEN: She wondered
if she could make endangered
Pillar corals happy enough
to reproduce. Something
like that had never been
done before with Florida
corals in aquariums.
KERI O'NEIL: So you have to get
all the seasonal cues right,
the change in temperature,
the change in daylight,
sunrise, sunset, the moon
phase, all of these different
cues have to be just
right in order for that
one event to occur around
the full moon of August.
MILES O'BRIEN: The spawning
happened on their first
try in August of 2019.
KERI O'NEIL: We were just
cheering and yelling and
calling everybody, like,
come in. We need help.
(LAUGHTER)
KERI O'NEIL: And it's
happened like clockwork
every year since then.
MILES O'BRIEN: So what started
as a gene bank five years ago
is now a huge thriving
coral breeding center.
Keri O'Neil occasionally joins
divers from the Florida Fish and
Wildlife Conservation Commission
as they cement their offspring
onto ailing reefs. The team
uses little bamboo teepees,
so the young corals don't
become fish hors d'oeuvre.
So far, they are thriving,
maybe because they're young
and strong, or maybe the worst
of the epidemic has passed.
Eventually, O'Neil hopes they
will find the genes that make
coral resistant and selectively
breed animals that are immune to
stony coral tissue loss disease.
But, remember, the disease
is just one of many threats.
KERI O'NEIL: We cannot
save coral reefs without
stopping climate change
and cleaning up our
environment. That takes time. In
the meantime, we need to ensure
that we don't lose the diversity
that we have now, so that we
can build back the population.
Our work here is buying us time.
MILES O'BRIEN: When Karen
Neely swims past healthy
corals that she has treated,
she feels the same way.
KAREN NEELY: I definitely
don't feel like it's
a futile effort. And I do feel
like we have to do something.
If you like seafood,
you like coral reefs.
If you like vacationing
in Florida, you like coral
reefs. You might not know it,
but it's super important that
we have them, and it's pretty
problematic when we lose them.
I think, in my lifetime, we will
either start to see the swing
back towards more healthy reefs,
or we will see reefs continue
to decline into something
almost unrecognizable.
MILES O'BRIEN: Imagine
that, a world without
thriving coral reefs.
Not a pretty thought. It's
heartbreaking to watch it
happening right before my eyes.
For the "PBS NewsHour,"
I'm Miles O'Brien 30
feet beneath the surface
at Looe Key, Florida.