Far out in the remote northwestern Pacific,
islands formed by an ancient volcano rise

out of the sea
They re very, very hard to reach.

It s very remote. It s maybe 500 miles
from the nearest population center so it gets

very few visitors.
It was like Jurassic Park pretty much. I was

really impressed.
These are the islands of Maug, an uninhabited

paradise near the northern tip of the Mariana
Islands.

Maug is unlike any other place I ve ever
been in the world -you re in the middle

of absolutely nowhere and you come to what
looks from a distance just like an island,

and then you see that it s a big volcanic
crater essentially. And you are able to sail

inside and it all of a sudden becomes not
just this big roiling Pacific but almost this

lake inside the ocean-- flat, calm, very pleasant
with these big, kind of walls rising up around

you and that just in and of itself is special
and amazing.

Maug used to be a volcano that was up above
the water, but there was a large eruption

at some point and the whole top of the volcano
collapsed down and it left this ring of three

islands around that have openings big enough
to drive the ship into, and it s about a

mile and a half across so it s a pretty
good size caldera inside.

Within this caldera are unspoiled coral reefs
The coral diversity is impressive.

There s areas where you have almost 100
percent coral coverage and just fields of

coral, and just the most pristine reefs you
could imagine.

But what makes these waters of particular
interest to scientists is what else can be

found beneath the surface.
You can jump in the water, dive down 30 feet

and feel that the ground there is actually
hot and you ve got this hot water coming

out and gas bubbles.
I ve heard someone say that it s like

diving in champagne, and it absolutely is.
It s not an exaggeration. It s pretty

amazing.
Volcanic gases are typically dominated by

CO2, so when we heard that there were gas
bubbles coming out within the coral reef area

something clicked and we said, hey this is
an opportunity to go look at how volcanic

CO2 might be affecting the coral reef communities
and use it as an analog to what s going

on in the bigger ocean.
The chemistry of seawater is changing throughout

the world s oceans. Since the dawn of the
Industrial Revolution, human activities have

increased the amount of CO2 that is released
into the atmosphere. The oceans naturally

absorb a percentage of atmospheric carbon
dioxide every year. As the levels of CO2 increase

in the atmosphere, more of it is taken up
by the oceans as well.

And this causes essentially a lower pH and
a more acidic condition, so this creates a

situation where it s harder for corals,
or any other organism that forms a calcium

carbonate or hard skeleton to actually lay
down those skeletons and to calcify.

This is known as ocean acidification. One
of several effects elevated levels of CO2

is having on the world s oceans, it is predicted
to severely impact coral reefs in the future.

We could use this local volcanic activity
to study that process in an experiment that s

sort of set up by nature for us where the
volcano is putting CO2 into the water and

affecting the chemistry and if conditions
were right we could possibly use that to study

how ocean acidification may be affecting coral
growth and what the future of coral reefs

might look like.
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/Emocean Sports
inspiring the pursuit of adventure and water

sports. And by the following In Memory of
Harriet Fagan, the Do Unto Others Trust, and

the Friends of Changing Seas.
Maug is part of the Commonwealth of the

Northern Mariana Islands, a United States
territory consistingof fourteen islands in

the northwestern Pacific.
I just absolutely love my island home.

Geographically we are approximately 1,500
miles east of the Philippines and Tokyo and

little over 3,000 miles from the islands of
Hawaii, and 6,000 miles plus from the Pacific

coast of the United States. So, we re pretty
far out here in the northwestern pocket of

the Pacific.
It s right near the Mariana Trench, deepest

part of the ocean in the world, and it s
a very volcanically active area.

Maug itself hasn t erupted for a while,
it formed a caldera some thousands of years

ago, and built a volcanic, a small volcanic
dome in the center of that caldera, but it

hasn t erupted in historic times. It s
not dead, there s still heat coming out

and magmatic gases coming out, but it s
not one of the most active volcanoes around.

But potentially it could increase in activity
again.

In the spring of 2014 a group of twenty marine
scientists from across the United States and

its Pacific Island territories headed to Maug
for a ten day research expedition organized

by scientists from the National Oceanic and
Atmospheric Administration, or NOAA.

First of all we wanted to look at the actual
chemistry of the water there.

So we took bottle samples and looked at the
chemistry over a different space and we mapped

that out and kind of created a map of this
gradient of CO2.

And the beauty of this system is that it s
well contained in a relatively calm environment

and in depths that scuba divers can investigate.
The first order question was do these vents

change the ocean pH in this area enough to
affect the corals. And the answer is definitely

yes. And then secondly, can you take advantage
of a gradient in pH conditions to change from

normal background pH to lower and lower pH
as you get closer to the vents, to look at

the corals that are living in those different
pH environments and see how they are growing.

Maug is one of a handful of spots that offer
scientists a natural laboratory to investigate

what ocean acidification could look like by
the end of our century.

Based on these localized differences in pH
levels, the team of scientists researching

ocean acidification selected three distinct
study sites. One is close to a vent site,

where waters are very acidic and the bottom
is dominated by algae.

The CO2 conditions there are analogous to
what we can expect by the end of the century.

About 50 meters away, the scientists selected
their 2nd study location. At this intermediate

site the CO2 levels are lower than at the
vent site, but higher than in most current

day ocean waters.
There are some species that are more stress

tolerant and so in the intermediate site we
kind of found this community where some species

were present, some were not. Coral cover was
not as high and it was kind of just holding

on.
The third site represented a coral reef with

pH levels that are equivalent to what can
be found near most reefs today. It s located

a kilometer away from the vent site.
I want to say something like 60% coral. These

beautiful massive coral colonies that were
many meters apart, huge, hundreds of years

old, all sorts of branching corals, fishes,
we saw some sharks, all sorts of amazing species.

So it s very stark difference.
To better understand the impact of high CO2

levels on corals, researchers collected core
samples from the same species of coral at

each study site.
We took small cores, from these large colonies

and we immediately sealed them up underwater
so that nothing, you know, gets into those

holes.
This process does not permanently harm the

corals.
Once back in the lab in Miami, Florida, these

cores are analyzed using a cat scanner.
So what a cat scanner does, and this is exactly

the same as you would get in a doctor s
office, is it takes a whole bunch of x-ray

images and lines them up in a way that you
create a three dimensional structure. And

so this view that we see here is both the
top down of this coral core as well as the

sides, and then a 3D model here. You can see
that we can manipulate it all around like

this. Um, and so, if you for instance move
right here this actually will allow us to

scroll through and you can see year after
year how each of these little coral polyps

grows up and down and if you look carefully
you can see these changes in brightness, which

are equivalent to changes in density. And
these are the yearly rings, the yearly density

rings, that we actually use to measure coral
calcification and coral growth, just like

tree rings on a tree. So you can see all these
yearly bands and then we re able to graph

this out and look at these changes in density
from year to year then measure yearly calcification.

When we analyzed the cores from Maug we found
that distance in between each of these high

density yearly bands was less in the high
CO2 conditions and this means that nearer

to the vents the corals were growing less
every year, which is one of the things that

is predicted to occur with ocean acidification.
So we re really trying to figure out how

ocean acidification actually slows down calcification.
So it s not just that corals are putting

skeleton down slower, it s actually fundamentally
changing the skeleton that they put down.

While in the field, the scientists wanted
to study how much coral fragments would grow

over a three-month period in varying levels
of acidity.

They were collecting branching corals from
one spot and putting them on discs and transplanting

them to move into an area where the pH was
a little bit lowered in two test sites, one

that was significantly impacted and one that
was just moderately impacted.

So with field experiments not everything works,
and actually what we found was in the period

from when we first went to when we returned
there was incredibly warm summer conditions

and caused a mass bleaching event.
Increased water temperatures are another threat

global climate change poses to coral reefs.
When water temperatures rise above normal,

corals lose their symbiotic algae, making
the corals look white or bleached. Corals

depend on these algae for nourishment, and
if temperatures are elevated for too long,

the corals will die.
And this actually affected a lot of our experiment

as well. Corals are dying and it s a bad
situation so, the experiment was messed up.

But while this experiment didn t pan out
as planned, the researchers did get some great

data from another.
It was kind of a side experiment, like, Oh!

Let s put these down and see what happens.
And what saw was pretty amazing.

So this may not look at all like the same
material that a coral skeleton is made up

of, but this is actually just very pure calcium
carbonate, just like a coral skeleton. And

we put these out at the high CO2, mid CO2
and control sites for about 3 months. On the

screen here, this is actually a sample from
the high CO2 site, and you see that all of

these little tiny, holes and tunnels that
are bored into the actual calcium carbonate

and these are called micro-boring algae -these
are microscopic and are actually inside the

coral skeleton.
In the intermediate site, you can see there s

less and in the control site there s even
less. So, we found that there were really

stark differences in the samples.
You can kind of think of it like a forest

where trees are essentially analogous to corals
in that they re forming this kind of complex

structure and in a forest fungi essentially
break down these trees and kind of cause it

to rot and decompose and break away. On coral
reefs there are similar organisms.

As the oceans get more acidic, it s easier
for these organisms to break down the coral

skeletons. And this is kind of a double whammy
because you have a situation where you have

faster erosion and slower coral growth, and
so you have kind of a situation where these

reef frameworks are not able to expand and
are also getting eaten away, and it s essentially

a very bad situation for these amazing ecosystems
and habitats.

Another team of NOAA scientists analyzed the
hot water and gases emitted by the hydrothermal

vents. Dr. David Butterfield has spent his
career studying how deep sea volcanoes work

More than 70% of the volcanic activity on
the planet takes place underneath the sea

surface and that has an effect on ocean circulation,
ocean chemistry, and so we need to study these

things just to know how the earth works.
We measured the composition of the gas bubbles

that are coming out in the system, we found
they were about 60% CO2, which is much higher

than what you find in air, less than 1%, and
the balance of the gas was mostly nitrogen

and some trace gases that come out of the
magma chamber.

And then there s the warm water that s
coming out of the ground it comes out and

sort of mixes up into the seawater above it
this warm water carries that low pH signal

with it. The gas bubbles are rising up through
the water and basically coming right out the

surface but the lower pH water that s coming
up through the seafloor, that s where that

acidified signal is coming from.
The warm waters coming up from the vents also

contain trace elements that dissolved out
of the volcanic rock.

They re loaded with iron and they also have
other metals that potentially might be toxic.

We found that there was very high arsenic
in the warm fluids that were coming out of

the sea floor there, and that s actually
a relatively common thing for shallow hydrothermal

systems. So you know we have questioned is
the arsenic affecting the growth of the corals

and there s very little experimentation
that s been done that can answer that question

so far.
The iron makes the water cloudy because it

is forming these particles that absorb light,
so the corals there get less light.

You have to isolate what is actually affecting
those corals. Is it just the pH? Is it the

metals that are coming out? Increase in temperature,
maybe. And so you have to look carefully at

all those things to know what effect you re
actually measuring.

It s very difficult to completely eliminate
the possibility of other factors. Um, we specifically

designed our study areas to not be in the
area of very, very high, rapid activity so

that they were removed and they were more
natural. We looked at gas composition and

a whole bunch of different things to try to
eliminate those factors.

Maug is part of the Marianas Trench Marine
National Monument, signed into law by President

Bush in 2009. The monument protects roughly
95-thousand square miles of land and sea,

including the famous Mariana Trench, the deepest
point in the oceans.

These protections, as well as Maug s remoteness,
mean its coral reefs are less impacted by

the stressors other reefs encounter in more
populated areas.

The other impacts such as fishing, such as
nutrient runoff, things that are influencing

reef systems all over the world were not as
big of a deal there, yet we still saw this

shift, this complete ecosystem loss due to
CO2.

Ecosystems are so complex. We have a hard
time understanding how everything kind of

works its way out and how it will manifest
in the end. What we have found is that the

accumulation of all of these multiple stressors
absolutely can cause more rapid, more catastrophic

degradation then when simply one stressor
is present.

Another tool that helps scientists understand
and quantify Maug s ecosystems are detailed

maps of the study sites - created by combining
high resolution images into large scale photo

mosaics.
What this entails is establishing a 100 square

meter plot and then taking about 3,000 images
within that plot that are then stitched into

one large landscape image which allows us
to look at the spatial patterning and the

spatial arrangement of all of the organisms
that are in that image.

To create these photo mosaics, the divers
stake out a 10 meter by 10 meter area.

We set a series of corner markers and floats
that allow us to see the plot and then we

have a frame that holds two high resolution
cameras one set to 18 millimeters the other

set to 55 millimeters. And we swim repeated
passes across this plot. The camera s set

to interval timer so both cameras taking a
picture every second, and the idea is for

the swimmer to swim every square centimeter
of that plot. You do it in a reverse lawnmower

pattern so you go up and down and then side
to side trying to do about 20 passes per plot,

a minimum of 10 passes per plot so that there s
a high degree of overlap between images, both

in the passes, and you re swimming pretty
slow it s just a little flutter kick

so that each image has about 90 percent overlap.
While one diver is taking pictures, a second

diver is taking very exact measurements. This
will ensure that all the images are to scale

as they are stitched together into one very
high resolution image.

If you zoom all the way out it s the view
that a scuba diver or a snorkeler would have

when they splashed off the boat on the surface
looking straight down. But as you zoom in,

it would be the same resolution as you would
see with your own eye going all the way down

to the polyp structure of the individual corals.
And what we re able to do is create a map

that has the distribution of all those organisms
on there and then we go through and classify

them down to the species level if we can.
And what we re able to do from that is then

extract all that data so that each species
will come off as an individual layer and it

allows us to create a whole lot of metrics
such as size distributions. We can do nearest

neighbor analyses. We can do a lot of techniques
that have typically been confined to the terrestrial

realm because they ve been able to have
these large satellite-derived images.

Over the course of the ten-day research expedition,
scientists worked hard to better understand

this shallow hydrothermal vent system and
gain insight into the impacts climate change

will have on coral reefs in the future.
This is such a unique experience to have all

these different collaborators come together
on board the ship. The team that we assembled

for this expedition was a diverse group from
many different institutions.

We had chemists, geochemists, volcanologists.
We had coral experts, biologists, coral ecologists,

people who study algae, photographers who
could make maps of the sea floor and just

a really diverse group of people to put it
all together.

We had local partners doing diving to actually
analyze the species composition. I don t

know the species of algae and the species
of coral in that area and these guys are experts

and were able to identify everything to a
very fine taxonomic level. It was amazing

an amazing field team and really pulling this
all together was really, really important

for actually describing it and telling the
story that is Maug.

A lot of the local people should communicate
their knowledge about the archipelago. This

is my first trip up here so as a Chamorro,
it s like I ve fulfilled a dream kind

of thing. I made it up the whole chain. I ve
been able to see all the islands. So it s

something important for me.
I think we re in a period where we really

have to do something now about the global
increase in CO2. It may be too late to prevent

major effects, but even so we need to figure
out a way to slow it down or possibly remove

CO2 from the atmosphere somehow.
We re giving up a lot of our resources just

for the money when it s not all about that.
What about, what about your kids, what about

your kid s kids. You know I want my son
to experience what I experienced. I want his

son to experience that too. It s about what
you, what you leave behind for your next generation.

So they always teach us to respect our elders
and make your ancestors proud.

Our ancestors -they had such a connection
with environment. Something got lost along

the way and thank goodness that we have a
number of individuals that have such foresight.

I think that s the ancestor speaking through
us that this is important now. Now is the

time to act to protect what you have left.
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/Emocean Sports
inspiring the pursuit of adventure and water

sports. And by the following In Memory of
Harriet Fagan, the Do Unto Others Trust, and

the Friends of Changing Seas.