How pollution is changing the ocean's chemistry | Triona McGrath | TEDxFulbrightDublin
-
0:23 - 0:27Do you ever think about how important
the oceans are in our daily lives? -
0:29 - 0:32The oceans cover two-thirds of our planet.
-
0:32 - 0:35They provide half the oxygen we breathe.
-
0:35 - 0:37They moderate our climate.
-
0:37 - 0:41And they provide jobs
and medicine and food -
0:41 - 0:46including 20 percent of protein
to feed the entire world population. -
0:47 - 0:50People used to think
that the oceans were so vast -
0:50 - 0:52that they wouldn't be affected
by human activities. -
0:54 - 0:57Well today I'm going to tell you
about a serious reality -
0:57 - 1:02that is changing our oceans
called ocean acidification, -
1:02 - 1:04or the evil twin of climate change.
-
1:06 - 1:12Did you know that the oceans have absorbed
25 percent of all of the carbon dioxide -
1:12 - 1:14that we have emitted to the atmosphere?
-
1:14 - 1:18Now this is just another great service
provided by the oceans -
1:18 - 1:21since carbon dioxide
is one of the greenhouse gases -
1:21 - 1:23that's causing climate change.
-
1:24 - 1:28But as we keep pumping
more and more and more -
1:28 - 1:30carbon dioxide into the atmosphere
-
1:30 - 1:33more is dissolving into the oceans.
-
1:33 - 1:36And this is what's changing
our ocean chemistry. -
1:38 - 1:40When carbon dioxide dissolves in seawater,
-
1:40 - 1:42it undergoes a number
of chemical reactions. -
1:43 - 1:44Now lucky for you,
-
1:44 - 1:47I don't have time to get into
the details of the chemistry for today. -
1:48 - 1:51But I'll tell you as more
carbon dioxide enters the ocean, -
1:51 - 1:53the seawater pH goes down.
-
1:54 - 1:58And this basically means that there
is an increase in ocean acidity. -
1:59 - 2:03And this whole process
is called ocean acidification. -
2:03 - 2:06And it's happening
alongside climate change. -
2:08 - 2:12Scientists have been monitoring
ocean acidification for over two decades. -
2:12 - 2:15This figure is an important
time series in Hawaii, -
2:15 - 2:20and the top line shows steadily increasing
concentrations of carbon dioxide, -
2:20 - 2:23or CO2 gas, in the atmosphere.
-
2:23 - 2:26And this is directly as a result
of human activities. -
2:27 - 2:31The line underneath shows the increasing
concentrations of carbon dioxide -
2:31 - 2:34that is dissolved
in the surface of the ocean -
2:34 - 2:37which you can see is increasing
at the same rate -
2:37 - 2:40as carbon dioxide in the atmosphere
since measurements began. -
2:42 - 2:45The line on the bottom shows
then shows the change in chemistry. -
2:45 - 2:48As more carbon dioxide
has entered the ocean, -
2:48 - 2:50the seawater pH has gone down,
-
2:51 - 2:55which basically means there has been
an increase in ocean acidity. -
2:57 - 3:01Now in Ireland, scientists are also
monitoring ocean acidification -- -
3:01 - 3:04scientists at the Marine
Institute and NUI Galway. -
3:04 - 3:08And we, too, are seeing
acidification at the same rate -
3:08 - 3:11as these main ocean time-series
sites around the world. -
3:11 - 3:14So it's happening right at our doorstep.
-
3:16 - 3:19Now I'd like to give you an example
of just how we collect our data -
3:19 - 3:21to monitor a changing ocean.
-
3:22 - 3:25Firstly we collect a lot of our samples
in the middle of winter. -
3:25 - 3:28So as you can imagine,
in the North Atlantic -
3:28 - 3:30we get hit with some seriously
stormy conditions -- -
3:30 - 3:33so not for any of you
who get a little motion sickness, -
3:33 - 3:36but we are collecting
some very valuable data. -
3:37 - 3:40So we lower this instrument
over the side of the ship, -
3:40 - 3:42and there are sensors
that are mounted on the bottom -
3:42 - 3:45that can tell us information about
the surrounding water, -
3:45 - 3:47such as temperature
or dissolved oxygen. -
3:48 - 3:52And then we can collect our seawater
samples in these large bottles. -
3:52 - 3:55So we start at the bottom,
which can be over four kilometers deep -
3:55 - 3:57just off our continental shelf,
-
3:57 - 4:01and we take samples at regular intervals
right up to the surface. -
4:02 - 4:04We take the seawater back on the deck,
-
4:04 - 4:06and then we can either
analyze them on the ship -
4:06 - 4:10or back in the laboratory
for the different chemicals parameters. -
4:11 - 4:13But why should we care?
-
4:14 - 4:18How is ocean acidification
going to affect all of us? -
4:20 - 4:23Well, here are the worrying facts.
-
4:24 - 4:29There has already been an increase
in ocean acidity of 26 percent -
4:30 - 4:34since pre-industrial times,
which is directly due to human activities. -
4:35 - 4:39Unless we can start slowing down
our carbon dioxide emissions, -
4:40 - 4:46we're expecting an increase
in ocean acidity of 170 percent -
4:46 - 4:48by the end of this century.
-
4:49 - 4:52I mean this is within
our children's lifetime. -
4:53 - 4:59This rate of acidification
is 10 times faster -
4:59 - 5:05than any acidification in our oceans
for over 55 million years. -
5:06 - 5:11So our marine life have never,
ever experienced -
5:11 - 5:14such a fast rate of change before.
-
5:14 - 5:18So we literally could not know
how they're going to cope. -
5:19 - 5:24Now there was a natural acidification
event millions of years ago, -
5:24 - 5:28which was much slower
than what we're seeing today. -
5:28 - 5:33And this coincided with a mass extinction
of many marine species. -
5:34 - 5:36So is that what we're headed for?
-
5:37 - 5:38Well, maybe.
-
5:39 - 5:42Studies are showing
some species are actually doing quite well -
5:42 - 5:45but many are showing a negative response.
-
5:48 - 5:52One of the big concerns is
as ocean acidity increases, -
5:52 - 5:56the concentration of carbonate
ions in seawater decrease. -
5:57 - 6:00Now these ions are basically
the building blocks -
6:00 - 6:03for many marine species
to make their shells, -
6:04 - 6:08for example crabs or mussels, oysters.
-
6:09 - 6:11Another example are corals.
-
6:11 - 6:14They also need these carbonate
ions in seawater -
6:14 - 6:18to make their coral structure
in order to build coral reefs. -
6:20 - 6:22As ocean acidity increases
-
6:22 - 6:25and the concentration
of carbonate ions decrease, -
6:26 - 6:30these species first find it more difficult
to make their shells. -
6:31 - 6:34And at even even lower levels,
they can actually begin to dissolve. -
6:36 - 6:39This here is a pteropod,
it's called a sea butterfly. -
6:40 - 6:43And it's an important food source
in the ocean for many species, -
6:43 - 6:46from krill to salmon right up to whales.
-
6:48 - 6:51The shell of the pteropod
was placed into seawater -
6:51 - 6:55at a pH that we're expecting
by the end of this century. -
6:57 - 7:02After only 45 days
at this very realistic pH, -
7:02 - 7:06you can see the shell
has almost completely dissolved. -
7:08 - 7:12So ocean acidification could affect
right up through the food chain -- -
7:13 - 7:15and right onto our dinner plates.
-
7:15 - 7:19I mean who here
likes shellfish? Or salmon? -
7:19 - 7:21Or many other fish species
-
7:21 - 7:24whose food source
in the ocean could be affected? -
7:27 - 7:29These are cold-water corals.
-
7:29 - 7:32And did you know we actually have
cold-water corals in Irish waters, -
7:32 - 7:34just off our continental shelf?
-
7:35 - 7:39And they support rich biodiversity,
including some very important fisheries. -
7:40 - 7:43It's projected that
by the end of this century, -
7:44 - 7:4970 percent of all known cold-water corals
in the entire ocean -
7:50 - 7:55will be surrounded by seawater
that is dissolving their coral structure. -
7:58 - 8:02The last example I have
are these healthy tropical corals. -
8:03 - 8:07They were placed in seawater at a pH
we're expecting by the year 2100. -
8:09 - 8:14After six months, the coral
has almost completely dissolved. -
8:16 - 8:18Now coral reefs support
-
8:18 - 8:2525 percent of all marine life
in the entire ocean. -
8:25 - 8:27All marine life.
-
8:28 - 8:32So you can see: ocean
acidification is a global threat. -
8:33 - 8:35I have an eight-month-old baby boy.
-
8:36 - 8:40Unless we start now to slow this down,
-
8:40 - 8:44I dread to think what our oceans
will look like when he's a grown man. -
8:46 - 8:48We will see acidification.
-
8:48 - 8:52We have already put too much
carbon dioxide into the atmosphere. -
8:53 - 8:56But we can slow this down.
-
8:56 - 9:01We can prevent the worst-case scenario.
-
9:01 - 9:03The only way of doing that
-
9:03 - 9:06is by reducing our
carbon dioxide emissions. -
9:07 - 9:12This is important for both you and I,
for industry, for governments. -
9:12 - 9:16We need to work together,
slow down ocean acidification -
9:16 - 9:19and then we can slow down global warming
-
9:19 - 9:22slow down ocean acidification,
-
9:22 - 9:26and help to maintain a healthy ocean
and a healthy planet -
9:26 - 9:30for our generation
and for generations to come. -
9:32 - 9:36(Applause)
- Title:
- How pollution is changing the ocean's chemistry | Triona McGrath | TEDxFulbrightDublin
- Description:
-
In this talk, Dr. Triona McGrath explains how our oceans are changing due to increasing levels of carbon dioxide in the atmosphere and how it will impact our marine life. Triona shares her thoughts on ocean acidification and explain why it is the evil twin of climate change.
Dr. Triona McGrath is a Fulbright scholar and post-doctorate research fellow, currently working with the National University of Ireland, Galway and the Marine Institute, Ireland. Her primary area of research is chemical oceanography where she is investigating ocean acidification in Irish marine waters. In 2014, Triona was a Fulbright-Marine Institute Scholar at the Scripps Institute of Oceanography in San Diego.
This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at http://ted.com/tedx
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDxTalks
- Duration:
- 09:45
TED Translators admin edited English subtitles for Ocean acidification - the evil twin of climate change | Triona McGrath | TEDxFulbrightDublin | ||
TED Translators admin edited English subtitles for Ocean acidification - the evil twin of climate change | Triona McGrath | TEDxFulbrightDublin |