ongoing media reporting initiative

called Peril & Promise,

our ongoing series of reports on the human impact of

and solutions for climate change.

- Welcome to WEDU Quest.

I'm Dr. Shannon McQuaig.

The world's oceans cover 70% of the earth

and are comprised of 321 million cubic miles of seawater,

so vast in size it would seem unimaginable

that humans could alter its chemistry.

But scientists at Mote Marine Laboratories

in Sarasota, Florida are researching

how we have altered the pH of oceans and estuaries.

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- Ocean acidification has been called

the other carbon dioxide problem

or the evil twin of climate change.

We've seen the osteoporosis of the sea.

And basically what it's related to

is the fact that we are putting a lot of anthropomorphic

carbon dioxide into our atmosphere.

So we're burning a lot of fossil fuels,

and there's other ways that CO2

is getting into the atmosphere.

But we're putting it in the atmosphere

at a faster and faster rate.

And about 30% of that CO2 gets absorbed by our ocean.

It's basically dropping the pH,

which is where we get the terminology ocean acidification.

It's becoming more acidic than what levels

that it has been normally in the past.

And that kind of brings about a couple of consequences

for some of our marine species.

Our marine organisms and even our marine communities,

it can cause dissolution of shells or skeletons.

Those same organisms that build their own shells

and build their own skeletons,

they actually take chemicals from the seawater to do that,

and this change, this ocean acidification

is starting to prevent that.

And that's just the tip of the iceberg.

- [Narrator] Dr. Emily Hall studies the impact

of ocean acidification and global warming

on corals and other ocean species

dependent on calcium carbonate.

- [Emily] We're looking to see if there's going to be

changes in growth rates or other physiological changes

on these individual organisms,

and we are finding that there are.

There are negative effects from ocean acidification,

and when coupled with warming or climate change,

we can even see doubly stressed on these organisms.

- [Narrator] Her research on coral is done

to exacting standards.

- [Emily] We manipulate the chemistry of the seawater.

So we bubble carbon dioxide gas into the seawater

and we monitor it by looking at the change in pH.

And so we take that water that we've bubbled

carbon dioxide into and we use it

in a flow-through system running over the corals.

- [Narrator] Her experiments include normal

or ambient seawater as the control

and this newly acidified water,

using the pH scale as measurement.

- The two targets that we're looking at

just here in this facility are about 8.1,

which is our ambient seawater.

We are using that as our ambient

because that's our typical open ocean seawater pH.

And then about 7.7,

which is what we're calling our acidified water,

and that's based on reports by the

Intergovernmental Panel on Climate Change

that has put out different models

talking about what we expect to see

our ocean acidification levels in 50 years from now,

100 years from now.

- [Narrator] The research on coral reefs continues

in an effort to save a critical ocean resource.

- They provide us with, for example, protection.

So protection against big storms

like hurricanes that come through.

They provide money to the state of Florida.

This is a place where people go for fishing,

where people go for eco-tourism,

to go scuba diving.

And not only that,

people who like to eat fish,

or something that they depend on

that is intricate with a coral reef ecosystem.

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- [Narrator] One of those food sources

we depend on are stone crabs.

Dr. Philip Gravinese,

a postdoctoral fellow at Mote Marine Labs,

has been studying the stone crab fishery.

He's researching the impact of acidification

on them in Florida's estuaries.

- We're focusing on them in particular

because it's such a large fishery here in Florida.

And it's a local fishery.

It's been around for several decades.

But they also live in habitats

where the pH is becoming more acidic

at a faster rate during certain times of the year.

Some of the causes for that is increased precipitation

during the rainy season that results in

more nutrients getting into the water,

organic nutrients,

The rainy season in Florida just so happens to coincide

with the stone crab's reproductive season.

- [Narrator] So he now leads research

on the effects of low pH environments

on stone crab reproduction.

- [Philip] Previous work that I've done

has shown that when the females

that have eggs on their abdomen

are put into acidified conditions

that mimic the future conditions for the ocean,

we see a significant decrease in their hatching success.

About 30% less larvae hatch.

And we also see their development,

their embryonic development, slow.

But we also have noticed that the females

that are in the acidified treatment

that are placed in the control.

- [Narrator] And how does one measure stress in stone crabs?

Dr. Gravinese explains that normal reflexes

is a sign of no stress.

- [Philip] So if you see back here,

it's a hard shell,

And so it's very similar like when you're kicking your knee

with a doctor hitting your knee.

If you just poke there,

you see how he moves?

So that means he's not stressed.

He has that reaction.

- [Narrator] But the response is different

for those crabs in low pH conditions.

- They must be undergoing some type

of physiological compensation to acclimate

and adjust to the lower pH,

and that could be the reason why

their stress level is a little bit higher

when they're in low pH conditions.

- [Narrator] As scientists at Mote Marine Laboratory

delve deeper into understanding

the effects of climate change and ocean acidification,

they gain new insights for how we all

can participate in solutions.

- We need to be trying to understand ways

that we can alleviate the effects

of some of these global stressors,

like ocean acidification and climate change.

And sometimes it's as simple

of an answer as plant more trees,

put more seagrass in the water,

or keep your backyards clean,

as well as trying to reduce our carbon emissions

and trying to slow down the process

of ocean acidification or climate change.

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- Quest for more research.

Visit mote.org/research.