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Ocean Acidification – The BIG global warming story
Reporter: Dr Graham Phillips
Producer: Dr Graham Phillips
Researcher: Anja Taylor
Camera: Kevin May
Sound: Steve Ravich
Editor: Chris Branagan
Transcript
Related Info
13 September 2007
This is a scary story. For decades we’ve been acidifying our oceans and we haven’t been aware of it.
We already know that warmer water is bleaching the coral of the Great Barrier Reef, but just recently it was discovered that there’s a new threat to the reef’s survival ... carbonic acid.
It’s only been in the science journals for the last few years but ocean acidification is a time bomb. It could not only destroy the Great Barrier Reef but it could wreak havoc on marine life around the world and, ultimately, affect land dwellers like ourselves.
“Ocean acidification is destined to be one of the biggest issues humanity has ever faced”, says reef expert Dr. Charlie Veron.
Ocean acidification is a side-effect of putting too much carbon dioxide into the skies. This gas ultimately ends up dissolved in the oceans where it forms weak carbon acid.
With the focus of global warming largely trained upon increased levels of CO2 above sea level, Catalyst asks the question, what’s happening below the surface of the ocean?
Presenter/Reporter Dr. Graham Phillips meets scientists who, for the first time, have found evidence that acidification is affecting marine organisms in the Southern Ocean.
Will this change the delicate balance of ocean chemistry that we take largely for granted?
 9:29mins | windows media . real player
 Transcript
Narration: This is a scary story. For decades we’re been acidifying our oceans and we haven’t been even aware of it till recently. Acidification is a time bomb.
Dr Will Howard:This problem will continue to affect the oceans even if we stopped all carbon emissions now.
Dr Charlie Veron: It’s like having a party on a railway track. You know the train is coming. And it’s really frightening. It’s terrifying.
Dr Will Howard:We have put in train a process that will probably last for centuries.
Dr Charlie Veron: It is the most serious problem of climate change. It is the big one.
Narration: The acidification of the world’s oceans is a side-effect of putting too much carbon dioxide into the skies. You may not have heard of it – it’s only been in science journals for the last few years - and the consequences could be huge.
Dr Charlie Veron is Australia’s foremost coral reef expert. He’s identified a staggering ¼ of the world’s corals. He’s keen show me the love of his life – the Great Barrier Reef, which he’s spent almost 40 years studying.
Dr Graham Phillips: Ok ready to go.
Dr Charlie Veron: Ready to go.
Narration: Coral reefs are home to some of the most diverse ecosystems in the world and Charlie says this protected reef on the edge of Heron Island is one of the healthiest he’s seen. The problem is coral reefs will be one of the first things damaged by acidification.
Dr Charlie Veron: If we were to continue producing carbon dioxide at the rate we are now, by mid-century every coral reef in this world will stop growing. They will all be going backwards.
We do know what happens to corals when they get acidified. They can’t build their skeletons, they get brittle, they grow slower.
And this is something that is not really in doubt. The chemistry of acidification is quite well known.
Dr Graham Phillips: Could we lose the reefs?
Dr Charlie Veron: We will lose the reefs. There’s no doubt about it. There can’t possibly be any doubt about it. If if we keep on producing carbon dioxide at the rate we are.
Narration:Acidification is caused by our carbon dioxide emissions not staying up the atmosphere. They ends up dissolved into the oceans, mixed in by the wind and waves to form carbonic acid.
To understand how this acid damages coral reefs you need to know how reefs form. They’re produced by vast colonies of little sea anemone like creatures – they’re the actual corals.
Dr Charlie Veron: You can see here some really big colonies. Hundreds of colonies there all together. And the actual coral itself.
Every tiny little lip here is an individual coral.
Dr Graham Phillips: So that’s a little animal. Each one of those is a little animal.
Dr Charlie Veron: Yeah, each of those is a little tiny animal. So in a colony like this you would literally see 1000s and 1000s – millions – of these little tiny animals.
Dr Graham Phillips: It’s the little critters’ internal workings that are relevant here. They have a stomach to digest food and water that comes in from the mouth at the top. And here’s the key: the corals excrete limestone. A multitude of corals endlessly expelling this rocky material - for 100s and 1000s of years - builds up the vast skeleton scaffolding of a coral reef.
And that’s the problem with acidification. As you learn in chemistry class…acids and limestone don’t mix.
Narration: Here’s a piece of dead coral skeleton. As you can see it’s hard – rock hard. But here’s the thing about limestone. Chemically it’s calcium carbonate and anything with carbonate in it can be dissolved by acid. Here’s a solution of weak hydrochloric acid and as you can see it bubbles instantly. Any sea creature that uses calcium carbonate to build its body will struggle as the oceans become more acidic.
Now the oceans won’t become anywhere near as acidified as this and actually dissolve corals, rather slight ocean acidification will stop them growing. Check this out.
Dr Graham Phillips: These are two relatively similar looking pieces of coral.
Dr Charlie Veron: Yeah they are, yeah they are. That one’s grown in a natural environment. You can try and crush it.
Dr Graham Phillips: Pretty hard
Dr Charlie Veron: Don’t try too hard cause you’ll just cut your fingers.
Dr Graham Phillips: Yeah
Dr Charlie Veron: Yeah corals are tough. This guy has grown in an environment where there is artificial acidification such would occur around the middle of this century. Now if I squeeze that.
Dr Graham Phillips: Oh yeah it’s just spongy
Dr Charlie Veron: Yeah I can crush it. It all falls to pieces.
Narration: While corals haven’t been affected yet, there are some important critters under even more immediate threat, according to new research out of Hobart.
Dr Graham Phillips: In this beaker of clear-looking water are 1000s of little creatures…plankton. They’re not as impressive as corals, of course, because you can’t see them, but they too build their bodies out of calcium carbonate.
Narration Could plankton have already been affected by acidification?
That would be disturbing because they’re at the very base of the ocean’s food web. Plankton are eaten by krill, for instance, and krill by the larger animals.
Dr Will Howard: This will have an ecological cascade effect right up to parts of the food web that are important to human beings, that is fish, shell fish for example a lot of the organisms that we depend on as food supply sources will directly or indirectly be effected by this process.
Narration: So a scientific expedition was mounted to the wild southern ocean to study the plankton. Down here is where the effects of ocean acidification would first appear.
Dr Will Howard:We see them first in the southern ocean because the southern ocean has absorbed a disproportionate amount of the anthropogenic carbon dioxide that has already entered the atmosphere because it’s a cold ocean and carbon dioxide is more soluble in colder water than in warmer water.
Narration: Plankton samples were collected…but how would the scientists know if the critters had been changed by acidification?
The trick was to compare them with plankton fossils extracted from sea floor mud. When the debris was washed away the little white flecks become visible…plankton from long before the industrial age.
When cleaned and dried, it’s under an optical microscope for a first peek.
Andrew: What I’m looking at under here is, there are about 4 or 5 different planktonic foraminifera, which are calcite shells.
Narration: The foraminifera’s calcium carbonate shells are what interest the scientists. Could they be becoming thinner and more feeble with ocean acidification?
To find out, it’s to the more powerful scanning electron microscope.
And the answer is yes. This is the first evidence in the world that acidification is already changing organisms in the ocean.
Dr Graham Phillips: So can we see those changes here?
Dr Will Howard:Yes we can.
What you see in this shell is much thicker crystals on the shell
Dr Graham Phillips: So the crystals are here.
Narration: That shell belongs to the pre-industrial plankton. This shell is one of today’s. It’s visibly more feeble.
Dr Will Howard:This shell is a thinner shell with a lot more porosity in it.
Narration: Side-by-side, the contrast is dramatic.
Dr Will Howard: These organisms have having to make thinner smaller shells than they would have in the pre-industrial ocean.
Narration: Now it’s too early to say what the flow on effects of more frail plankton species will be, but one concern for us land dwellers is that plankton currently take carbon dioxide out of the atmosphere.
Dr Will Howard: All this extra carbon dioxide derived from fossil fuels will remain in the atmosphere that much longer because the ocean will become saturated.
Narration: What worries Charlie is, major ocean acidification has helped extinguish life before in Nature. These formations in north-western Australia are the remains of coral reefs. They suddenly died 360 million years ago.
Dr Charlie Veron: And we call those the great mass extinction events. Mass extinction. That means the extermination of a huge percentage of life on Earth. And coral reefs have taken at least four million years to recover. Now that’s quite well known. That’s been known for most of my life.
Dr Will Howard:There really is only one mitigation strategy and that is in this case to limit the extent and rate of carbon emissions into the atmosphere.
Dr Charlie Veron: It’s no use saying by 2030 that we’ll do this or we’ll do that, by 2030 it will all be too late. That is the problem.
So we have to change. And humans are, I believe, very good at change.
But there’s not an ounce of hope in a world that wants to procrastinate and to say we can’t do this or that. We’re going to have to.
Story Contacts
Dr Charlie Veron
Dr Will Howard
Antarctic Climate & Ecosystems CRC
Related Info
Antarctic Climate & Ecosystems
Royal Society 2005 report on Ocean Acidification:
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