How pollution is changing the ocean's chemistry
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0:02 - 0:06Do you ever think about how important
the oceans are in our daily lives? -
0:08 - 0:11The oceans cover two-thirds of our planet.
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0:11 - 0:14They provide half the oxygen we breathe.
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0:14 - 0:16They moderate our climate.
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0:16 - 0:20And they provide jobs
and medicine and food -
0:20 - 0:25including 20 percent of protein
to feed the entire world population. -
0:26 - 0:29People used to think
that the oceans were so vast -
0:29 - 0:31that they wouldn't be affected
by human activities. -
0:32 - 0:35Well today I'm going to tell you
about a serious reality -
0:36 - 0:40that is changing our oceans
called ocean acidification, -
0:40 - 0:43or the evil twin of climate change.
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0:44 - 0:49Did you know that the oceans have absorbed
25 percent of all of the carbon dioxide -
0:49 - 0:52that we have emitted to the atmosphere?
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0:52 - 0:56Now this is just another great service
provided by the oceans -
0:56 - 0:59since carbon dioxide
is one of the greenhouse gases -
0:59 - 1:00that's causing climate change.
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1:01 - 1:05But as we keep pumping
more and more and more -
1:05 - 1:08carbon dioxide into the atmosphere
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1:08 - 1:10more is dissolving into the oceans.
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1:11 - 1:14And this is what's changing
our ocean chemistry. -
1:15 - 1:18When carbon dioxide dissolves in seawater,
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1:18 - 1:20it undergoes a number
of chemical reactions. -
1:20 - 1:22Now lucky for you,
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1:22 - 1:25I don't have time to get into
the details of the chemistry for today. -
1:25 - 1:29But I'll tell you as more
carbon dioxide enters the ocean, -
1:29 - 1:31the seawater pH goes down.
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1:32 - 1:36And this basically means that there
is an increase in ocean acidity. -
1:36 - 1:40And this whole process
is called ocean acidification. -
1:41 - 1:44And it's happening
alongside climate change. -
1:44 - 1:48Scientists have been monitoring
ocean acidification for over two decades. -
1:49 - 1:52This figure is an important
time series in Hawaii, -
1:52 - 1:57and the top line shows steadily increasing
concentrations of carbon dioxide, -
1:57 - 1:59or CO2 gas, in the atmosphere.
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1:59 - 2:02And this is directly as a result
of human activities. -
2:03 - 2:07The line underneath shows the increasing
concentrations of carbon dioxide -
2:07 - 2:10that is dissolved
in the surface of the ocean -
2:11 - 2:14which you can see is increasing
at the same rate -
2:14 - 2:17as carbon dioxide in the atmosphere
since measurements began. -
2:17 - 2:20The line on the bottom shows
then shows the change in chemistry. -
2:20 - 2:23As more carbon dioxide
has entered the ocean, -
2:23 - 2:25the seawater pH has gone down,
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2:26 - 2:30which basically means there has been
an increase in ocean acidity. -
2:31 - 2:35Now in Ireland, scientists are also
monitoring ocean acidification -- -
2:35 - 2:38scientists at the Marine
Institute and NUI Galway. -
2:38 - 2:42And we, too, are seeing
acidification at the same rate -
2:42 - 2:45as these main ocean time-series
sites around the world. -
2:46 - 2:49So it's happening right at our doorstep.
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2:50 - 2:53Now I'd like to give you an example
of just how we collect our data -
2:53 - 2:55to monitor a changing ocean.
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2:55 - 2:58Firstly we collect a lot of our samples
in the middle of winter. -
2:58 - 3:00So as you can imagine,
in the North Atlantic -
3:00 - 3:03we get hit with some seriously
stormy conditions -- -
3:03 - 3:06so not for any of you
who get a little motion sickness, -
3:06 - 3:08but we are collecting
some very valuable data. -
3:09 - 3:11So we lower this instrument
over the side of the ship, -
3:11 - 3:14and there are sensors
that are mounted on the bottom -
3:14 - 3:17that can tell us information about
the surrounding water, -
3:17 - 3:19such as temperature
or dissolved oxygen. -
3:19 - 3:23And then we can collect our seawater
samples in these large bottles. -
3:23 - 3:27So we start at the bottom,
which can be over four kilometers deep -
3:27 - 3:29just off our continental shelf,
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3:29 - 3:32and we take samples at regular intervals
right up to the surface. -
3:33 - 3:35We take the seawater back on the deck,
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3:35 - 3:38and then we can either
analyze them on the ship -
3:38 - 3:41or back in the laboratory
for the different chemicals parameters. -
3:41 - 3:42But why should we care?
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3:43 - 3:47How is ocean acidification
going to affect all of us? -
3:49 - 3:52Well, here are the worrying facts.
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3:53 - 3:59There has already been an increase
in ocean acidity of 26 percent -
3:59 - 4:03since pre-industrial times,
which is directly due to human activities. -
4:04 - 4:08Unless we can start slowing down
our carbon dioxide emissions, -
4:08 - 4:14we're expecting an increase
in ocean acidity of 170 percent -
4:14 - 4:17by the end of this century.
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4:18 - 4:20I mean this is within
our children's lifetime. -
4:22 - 4:27This rate of acidification
is 10 times faster -
4:27 - 4:34than any acidification in our oceans
for over 55 million years. -
4:34 - 4:38So our marine life have never,
ever experienced -
4:38 - 4:41such a fast rate of change before.
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4:42 - 4:45So we literally could not know
how they're going to cope. -
4:47 - 4:52Now there was a natural acidification
event millions of years ago, -
4:52 - 4:55which was much slower
than what we're seeing today. -
4:55 - 5:00And this coincided with a mass extinction
of many marine species. -
5:01 - 5:02So is that what we're headed for?
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5:03 - 5:04Well, maybe.
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5:05 - 5:09Studies are showing
some species are actually doing quite well -
5:09 - 5:12but many are showing a negative response.
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5:13 - 5:17One of the big concerns is
as ocean acidity increases, -
5:17 - 5:22the concentration of carbonate
ions in seawater decrease. -
5:22 - 5:25Now these ions are basically
the building blocks -
5:25 - 5:28for many marine species
to make their shells, -
5:29 - 5:33for example crabs or mussels, oysters.
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5:34 - 5:36Another example are corals.
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5:36 - 5:39They also need these carbonate
ions in seawater -
5:39 - 5:43to make their coral structure
in order to build coral reefs. -
5:44 - 5:47As ocean acidity increases
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5:47 - 5:50and the concentration
of carbonate ions decrease, -
5:50 - 5:55these species first find it more difficult
to make their shells. -
5:55 - 5:59And at even even lower levels,
they can actually begin to dissolve. -
6:00 - 6:03This here is a pteropod,
it's called a sea butterfly. -
6:04 - 6:07And it's an important food source
in the ocean for many species, -
6:07 - 6:10from krill to salmon right up to whales.
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6:11 - 6:15The shell of the pteropod
was placed into seawater -
6:15 - 6:18at a pH that we're expecting
by the end of this century. -
6:19 - 6:25After only 45 days
at this very realistic pH, -
6:25 - 6:29you can see the shell
has almost completely dissolved. -
6:30 - 6:34So ocean acidification could affect
right up through the food chain -- -
6:34 - 6:36and right onto our dinner plates.
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6:36 - 6:40I mean who here
likes shellfish? Or salmon? -
6:41 - 6:42Or many other fish species
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6:42 - 6:45whose food source
in the ocean could be affected? -
6:46 - 6:48These are cold-water corals.
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6:48 - 6:52And did you know we actually have
cold-water corals in Irish waters, -
6:52 - 6:54just off our continental shelf?
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6:54 - 6:58And they support rich biodiversity,
including some very important fisheries. -
6:59 - 7:02It's projected that
by the end of this century, -
7:02 - 7:0870 percent of all known cold-water corals
in the entire ocean -
7:09 - 7:13will be surrounded by seawater
that is dissolving their coral structure. -
7:17 - 7:21The last example I have
are these healthy tropical corals. -
7:21 - 7:26They were placed in seawater at a pH
we're expecting by the year 2100. -
7:27 - 7:33After six months, the coral
has almost completely dissolved. -
7:34 - 7:37Now coral reefs support
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7:37 - 7:4325 percent of all marine life
in the entire ocean. -
7:44 - 7:45All marine life.
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7:46 - 7:50So you can see: ocean
acidification is a global threat. -
7:51 - 7:53I have an eight-month-old baby boy.
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7:54 - 7:58Unless we start now to slow this down,
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7:58 - 8:02I dread to think what our oceans
will look like when he's a grown man. -
8:04 - 8:06We will see acidification.
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8:06 - 8:10We have already put too much
carbon dioxide into the atmosphere. -
8:11 - 8:14But we can slow this down.
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8:14 - 8:18We can prevent the worst-case scenario.
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8:19 - 8:21The only way of doing that
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8:21 - 8:24is by reducing our
carbon dioxide emissions. -
8:25 - 8:29This is important for both you and I,
for industry, for governments. -
8:30 - 8:33We need to work together,
slow down global warming -
8:34 - 8:36slow down ocean acidification
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8:36 - 8:41and help to maintain a healthy ocean
and a healthy planet -
8:41 - 8:44for our generation
and for generations to come. -
8:45 - 8:50(Applause)
- Title:
- How pollution is changing the ocean's chemistry
- Speaker:
- Triona McGrath
- Description:
-
As we keep pumping carbon dioxide into the atmosphere, more of it is dissolving into the oceans, leading to drastic changes in the water's chemistry. Triona McGrath researches this process, known as ocean acidification, and in this talk she takes us for a dive into an oceanographer's world. Learn more about how the "evil twin of climate change" is impacting the ocean -- and the life that depends on it.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 09:03
Brian Greene edited English subtitles for How pollution is changing the ocean's chemistry | ||
Brian Greene edited English subtitles for How pollution is changing the ocean's chemistry | ||
Brian Greene edited English subtitles for How pollution is changing the ocean's chemistry | ||
Brian Greene edited English subtitles for How pollution is changing the ocean's chemistry | ||
Brian Greene edited English subtitles for How pollution is changing the ocean's chemistry | ||
Brian Greene approved English subtitles for How pollution is changing the ocean's chemistry | ||
Brian Greene accepted English subtitles for How pollution is changing the ocean's chemistry | ||
Brian Greene edited English subtitles for How pollution is changing the ocean's chemistry |