How pollution is changing the ocean's chemistry | Triona McGrath

Summary

This speech highlights the vital role oceans play in sustaining life on Earth, from providing oxygen and food to regulating climate. However, it warns of the growing threat of ocean acidification due to the absorption of excess carbon dioxide from human activities. The speaker explains how this process is altering ocean chemistry, causing harm to marine species, including corals and shellfish. The talk urges immediate action to reduce carbon emissions, emphasizing that while ocean acidification is inevitable, we can still slow its progression to protect future generations and marine ecosystems.

Takeaways

• 🌊 The oceans cover two-thirds of the planet and are crucial for providing oxygen, moderating climate, and supporting jobs, medicine, and food sources.
• 🌍 The oceans have absorbed 25% of all carbon dioxide emissions, which is changing their chemistry and leading to ocean acidification.
• 📉 Ocean acidification refers to the decrease in seawater pH due to the absorption of excess carbon dioxide from the atmosphere.
• 📊 Scientists have been monitoring ocean acidification for over two decades, noting an increase in ocean acidity of 26% since pre-industrial times.
• 🌡️ Ocean acidification is happening globally, including in Ireland, where local scientists have observed the same trends as in major ocean time-series sites.
• 🐚 Increased ocean acidity reduces the availability of carbonate ions, which are essential for marine species like crabs, mussels, oysters, and corals to build their shells.
• 🦐 The shells of key species like the pteropod, a food source for many marine animals, are dissolving in seawater with lower pH, threatening the marine food chain.
• 🐠 Ocean acidification could disrupt marine ecosystems, potentially leading to a collapse of food sources for humans, such as shellfish and salmon.
• 🏝️ Coral reefs, which support 25% of all marine life, are at risk of dissolving due to increased ocean acidity, endangering marine biodiversity.
• 🚨 The speaker urges immediate action to reduce carbon dioxide emissions to slow down ocean acidification and prevent catastrophic impacts on marine life and human food sources.

Q & A

Why are the oceans important to our daily lives?

The oceans cover two-thirds of our planet, provide half of the oxygen we breathe, moderate our climate, and offer jobs, medicine, and food, including 20% of the protein for the global population.

What is ocean acidification?

Ocean acidification is the process where the ocean's pH decreases due to the absorption of carbon dioxide (CO2), making the water more acidic. It is often called the 'evil twin' of climate change.

How much carbon dioxide have the oceans absorbed?

The oceans have absorbed 25% of all carbon dioxide emitted into the atmosphere.

Why is ocean acidification happening alongside climate change?

As more CO2 is emitted into the atmosphere, more of it dissolves into the oceans. This increased absorption of CO2 changes the ocean's chemistry, leading to ocean acidification, which occurs simultaneously with climate change.

What has been the impact of ocean acidification since pre-industrial times?

There has been a 26% increase in ocean acidity since pre-industrial times due to human activities.

What is the projected increase in ocean acidity by the end of this century?

If carbon dioxide emissions are not reduced, ocean acidity is expected to increase by 170% by the end of this century.

How does ocean acidification affect marine life that build shells, like crabs and corals?

As ocean acidity increases, the concentration of carbonate ions in seawater decreases, making it harder for species like crabs, mussels, oysters, and corals to form their shells. In extreme cases, their shells may begin to dissolve.

What example was given of a species affected by ocean acidification?

A pteropod, also known as a sea butterfly, had its shell almost completely dissolve after 45 days in seawater with a pH expected by the end of this century.

Why are coral reefs important, and how are they threatened by ocean acidification?

Coral reefs support 25% of all marine life. By the end of this century, 70% of cold-water corals may be surrounded by seawater that is dissolving their structures due to ocean acidification.

What actions can be taken to slow down ocean acidification?

The key to slowing down ocean acidification is reducing carbon dioxide emissions. This requires efforts from individuals, industries, and governments to mitigate both global warming and acidification.

Outlines

00:00

🌊 The Vital Role of Oceans in Our Lives

Oceans cover two-thirds of the Earth and play a crucial role in supporting life by providing half the oxygen we breathe, moderating climate, and supplying food and jobs. Despite their vastness, human activities are now impacting the oceans, primarily through the absorption of carbon dioxide, which leads to ocean acidification—a significant issue alongside climate change. The script explains that the oceans have absorbed 25% of all human-emitted CO2, leading to a decrease in seawater pH, or an increase in ocean acidity. This phenomenon, tracked for over two decades, shows a direct correlation between atmospheric CO2 levels and oceanic changes, with scientists in Ireland observing similar trends. The script emphasizes the urgent need to monitor these changes to understand their effects on marine ecosystems.

05:03

🐚 Impact of Ocean Acidification on Marine Life

Ocean acidification poses a severe threat to marine species, especially those that rely on carbonate ions to build shells and structures, such as crabs, mussels, oysters, and corals. As acidity rises and carbonate ions decrease, these species struggle to form their shells and, at even lower levels, may experience shell dissolution. The script provides a poignant example of a pteropod, or sea butterfly, whose shell dissolved significantly in a short time under projected future ocean conditions. This change has the potential to disrupt the entire marine food chain, affecting everything from krill to whales and ultimately impacting human food sources. The script warns that if carbon emissions are not reduced, 70% of all cold-water corals could be surrounded by corrosive water by the century's end, threatening marine biodiversity and critical fishery resources.

Keywords

💡Ocean Acidification

Ocean acidification refers to the process where carbon dioxide (CO2) dissolves in seawater, leading to a decrease in the ocean's pH levels, making it more acidic. This is a major theme in the video, described as the 'evil twin of climate change.' The video explains how ocean acidification results from the absorption of CO2, and outlines its devastating effects on marine life, such as the dissolution of shells in species like pteropods.

💡Carbon Dioxide (CO2)

Carbon dioxide is a greenhouse gas that humans release into the atmosphere through activities like burning fossil fuels. The video explains that 25% of all CO2 emitted by humans has been absorbed by the oceans, which is beneficial in mitigating climate change, but simultaneously drives ocean acidification. The rising levels of CO2 both in the atmosphere and oceans are changing ocean chemistry, as highlighted in the time series data from Hawaii.

💡pH Levels

pH levels measure how acidic or basic a substance is. The video mentions that as CO2 dissolves in the ocean, the pH decreases, meaning the water becomes more acidic. This change in pH is a core indicator of ocean acidification. The narrator emphasizes that lower pH levels impact marine organisms that rely on calcium carbonate to form their shells and structures, such as corals and shellfish.

💡Greenhouse Gases

Greenhouse gases, like CO2, trap heat in the Earth's atmosphere and are a primary driver of climate change. The video discusses CO2 as one such gas, which, while helping to mitigate some effects of climate change by being absorbed into the oceans, simultaneously accelerates ocean acidification. The dual impact of CO2 on both climate change and ocean chemistry underscores the urgent need for emission reductions.

💡Marine Life

Marine life encompasses all organisms living in the ocean, many of which are affected by ocean acidification. The video provides examples of species like crabs, mussels, oysters, and corals, which rely on carbonate ions to build their shells and structures. As the concentration of these ions decreases due to acidification, marine species struggle to survive, which could have widespread consequences for ecosystems and food chains.

💡Carbonate Ions

Carbonate ions are essential for many marine organisms to build their shells and skeletons, such as corals and shellfish. The video explains that ocean acidification reduces the availability of these ions, making it difficult for these organisms to form their structures. Without sufficient carbonate ions, species like pteropods may even experience the dissolution of their shells, which can severely impact the marine food chain.

💡Coral Reefs

Coral reefs are diverse underwater ecosystems that support 25% of all marine life. The video emphasizes how ocean acidification is threatening coral reefs by reducing the availability of carbonate ions necessary for corals to build their structures. The projection that 70% of cold-water corals may be affected by the end of the century highlights the potential loss of biodiversity in these ecosystems.

💡Time Series Data

Time series data refers to a sequence of data points collected over time. In the video, time series data from Hawaii is used to show the rising levels of CO2 in the atmosphere and oceans, as well as the corresponding decrease in ocean pH. This data is critical in understanding the ongoing changes in ocean chemistry and serves as evidence of the accelerating rate of ocean acidification.

💡Pre-Industrial Times

Pre-industrial times refer to the period before the Industrial Revolution, which is used as a baseline for measuring human impacts on the environment. The video states that ocean acidity has increased by 26% since pre-industrial times, directly due to human activities. This historical comparison underscores the rapid and unprecedented nature of current environmental changes driven by CO2 emissions.

💡Food Chain

The food chain is the hierarchical system of organisms dependent on one another for food. The video explains that ocean acidification affects marine species at the bottom of the food chain, such as pteropods, which are essential food sources for larger animals like krill, salmon, and whales. Disruptions in this chain due to species struggling or dying from acidification could impact the entire ecosystem, including human food sources.

Highlights

The oceans provide half the oxygen we breathe and moderate the climate.

Oceans absorb 25% of the carbon dioxide we emit, helping to reduce greenhouse gases.

Ocean acidification, known as the 'evil twin of climate change,' is altering the ocean's chemistry.

Increased carbon dioxide levels lower seawater pH, causing a rise in ocean acidity.

Since pre-industrial times, ocean acidity has increased by 26% due to human activities.

If carbon emissions continue, ocean acidity could rise by 170% by the end of the century.

The current rate of ocean acidification is 10 times faster than any event in the past 55 million years.

Ocean acidification threatens marine species that rely on carbonate ions to form shells, such as crabs, mussels, and corals.

Cold-water corals in Irish waters could dissolve due to increasing ocean acidity.

25% of all marine life relies on coral reefs, which are severely threatened by ocean acidification.

By 2100, 70% of cold-water corals could be surrounded by water that dissolves their structure.

Ocean acidification affects the entire marine food chain, from small organisms like pteropods to fish species consumed by humans.

In Ireland, scientists from the Marine Institute and NUI Galway are actively monitoring ocean acidification.

Without action, ocean acidification will have drastic effects on marine ecosystems and human food sources.

Reducing carbon dioxide emissions is the only way to slow ocean acidification and protect marine life.

Transcripts

Do you ever think about how important the oceans are in our daily lives?

The oceans cover two-thirds of our planet.

They provide half the oxygen we breathe.

They moderate our climate.

And they provide jobs and medicine and food

including 20 percent of protein to feed the entire world population.

People used to think that the oceans were so vast

that they wouldn't be affected by human activities.

Well today I'm going to tell you about a serious reality

that is changing our oceans called ocean acidification,

or the evil twin of climate change.

Did you know that the oceans have absorbed 25 percent of all of the carbon dioxide

that we have emitted to the atmosphere?

Now this is just another great service provided by the oceans

since carbon dioxide is one of the greenhouse gases

that's causing climate change.

But as we keep pumping more and more and more

carbon dioxide into the atmosphere

more is dissolving into the oceans.

And this is what's changing our ocean chemistry.

When carbon dioxide dissolves in seawater,

it undergoes a number of chemical reactions.

Now lucky for you,

I don't have time to get into the details of the chemistry for today.

But I'll tell you as more carbon dioxide enters the ocean,

the seawater pH goes down.

And this basically means that there is an increase in ocean acidity.

And this whole process is called ocean acidification.

And it's happening alongside climate change.

Scientists have been monitoring ocean acidification for over two decades.

This figure is an important time series in Hawaii,

and the top line shows steadily increasing concentrations of carbon dioxide,

or CO2 gas, in the atmosphere.

And this is directly as a result of human activities.

The line underneath shows the increasing concentrations of carbon dioxide

that is dissolved in the surface of the ocean

which you can see is increasing at the same rate

as carbon dioxide in the atmosphere since measurements began.

The line on the bottom shows then shows the change in chemistry.

As more carbon dioxide has entered the ocean,

the seawater pH has gone down,

which basically means there has been an increase in ocean acidity.

Now in Ireland, scientists are also monitoring ocean acidification --

scientists at the Marine Institute and NUI Galway.

And we, too, are seeing acidification at the same rate

as these main ocean time-series sites around the world.

So it's happening right at our doorstep.

Now I'd like to give you an example of just how we collect our data

to monitor a changing ocean.

Firstly we collect a lot of our samples in the middle of winter.

So as you can imagine, in the North Atlantic

we get hit with some seriously stormy conditions --

so not for any of you who get a little motion sickness,

but we are collecting some very valuable data.

So we lower this instrument over the side of the ship,

and there are sensors that are mounted on the bottom

that can tell us information about the surrounding water,

such as temperature or dissolved oxygen.

And then we can collect our seawater samples in these large bottles.

So we start at the bottom, which can be over four kilometers deep

just off our continental shelf,

and we take samples at regular intervals right up to the surface.

We take the seawater back on the deck,

and then we can either analyze them on the ship

or back in the laboratory for the different chemicals parameters.

But why should we care?

How is ocean acidification going to affect all of us?

Well, here are the worrying facts.

There has already been an increase in ocean acidity of 26 percent

since pre-industrial times, which is directly due to human activities.

Unless we can start slowing down our carbon dioxide emissions,

we're expecting an increase in ocean acidity of 170 percent

by the end of this century.

I mean this is within our children's lifetime.

This rate of acidification is 10 times faster

than any acidification in our oceans for over 55 million years.

So our marine life have never, ever experienced

such a fast rate of change before.

So we literally could not know how they're going to cope.

Now there was a natural acidification event millions of years ago,

which was much slower than what we're seeing today.

And this coincided with a mass extinction of many marine species.

So is that what we're headed for?

Well, maybe.

Studies are showing some species are actually doing quite well

but many are showing a negative response.

One of the big concerns is as ocean acidity increases,

the concentration of carbonate ions in seawater decrease.

Now these ions are basically the building blocks

for many marine species to make their shells,

for example crabs or mussels, oysters.

Another example are corals.

They also need these carbonate ions in seawater

to make their coral structure in order to build coral reefs.

As ocean acidity increases

and the concentration of carbonate ions decrease,

these species first find it more difficult to make their shells.

And at even even lower levels, they can actually begin to dissolve.

This here is a pteropod, it's called a sea butterfly.

And it's an important food source in the ocean for many species,

from krill to salmon right up to whales.

The shell of the pteropod was placed into seawater

at a pH that we're expecting by the end of this century.

After only 45 days at this very realistic pH,

you can see the shell has almost completely dissolved.

So ocean acidification could affect right up through the food chain --

and right onto our dinner plates.

I mean who here likes shellfish? Or salmon?

Or many other fish species

whose food source in the ocean could be affected?

These are cold-water corals.

And did you know we actually have cold-water corals in Irish waters,

just off our continental shelf?

And they support rich biodiversity, including some very important fisheries.

It's projected that by the end of this century,

70 percent of all known cold-water corals in the entire ocean

will be surrounded by seawater that is dissolving their coral structure.

The last example I have are these healthy tropical corals.

They were placed in seawater at a pH we're expecting by the year 2100.

After six months, the coral has almost completely dissolved.

Now coral reefs support

25 percent of all marine life in the entire ocean.

All marine life.

So you can see: ocean acidification is a global threat.

I have an eight-month-old baby boy.

Unless we start now to slow this down,

I dread to think what our oceans will look like when he's a grown man.

We will see acidification.

We have already put too much carbon dioxide into the atmosphere.

But we can slow this down.

We can prevent the worst-case scenario.

The only way of doing that

is by reducing our carbon dioxide emissions.

This is important for both you and I, for industry, for governments.

We need to work together, slow down global warming

slow down ocean acidification

and help to maintain a healthy ocean and a healthy planet

for our generation and for generations to come.

(Applause)