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The search for planets beyond our solar system

The search for planets beyond our solar system

Jonathan Nally describes the astronomical projects searching for planets. So far, over 400 have
been found. Are they just lumps of rock or clouds of gas, or do some support life?

Transcript

Jonathan Nally: Attending astronomy conferences in the 1980s and early 1990s, I was often struck by
the dearth of interest in planetary science. But that changed in the mid-'90s when the first
exoplanets were discovered. These are planets that orbit other stars way beyond our solar system.
Over 400 have been found so far, and in recent weeks there have been some interesting discoveries
in this field. They've come from NASA's Kepler space mission which was launched in March last year
(2009) and is just now hitting its stride. It's a dedicated planet finding telescope. From its
vantage point a million kilometres from earth, it's using a huge digital camera to continuously
measure the light coming from 145,000 stars. If any of those stars have planets orbiting in the
line of sight to the telescope, Kepler will see a dip in the starlight. From the length of the dip
and how long between dips, scientists can work out the planet's orbit and estimate how massive it
is and how hot or cold it might be. In its first few months, Kepler has confirmed the presence of
some previously known exoplanets, and found some of its own. Five new ones were recently announced,
ranging in size from roughly Neptune up to somewhat bigger than Jupiter. Big gas planets. And they
all orbit very close to their stars, which means they're really hot. Hot jupiters, they call them.
Kepler's main job however is to find smaller rocky planets like earth, and especially those that
orbit within a star's habitable zone. This is the distance where it's neither too hot nor too cold
for a planet to have liquid water.

In fact, earth is actually just on the outside edge of our sun's habitable zone. The only reason we
aren't frozen solid is that we have a nice atmospheric greenhouse effect to keep the heat in,
otherwise our average global temperature would be about minus 15. Over its three-year lifetime,
Kepler might find a few of these small planets or it might find thousands. And this will directly
answer one of the big fundamental questions - are earth like planets rare out there, or are they
common?

But Kepler doesn't quite have the whole field to itself. There's also the European space agency's
COROT, the Convection, Rotation and Planetary Transits mission. Launched in 2006, it's doing much
the same job. One of its big discoveries last October is the exoplanet COROT 7B, a world only a few
times larger than earth. In fact, it's the first small rocky exoplanet found. Unfortunately though,
7B is much too close to its star to be in the habitable zone. Daytime temperatures are probably in
excess of 2,000 degrees. And as well as spotting planets, both telescopes are also used to do
helioseismology. As the name suggests, this is the science of sunquakes or starquakes.

Vibrations on the surface of a star are an indication of what's happening within, as huge
convection currents rise and fall. This inner turmoil makes stars literally ring like a bell. At
the University of Sydney, the aptly named Dr. Dennis Stello leads an international team using
Kepler data, focusing on the starlight instead of the planets. And already they found over 100
stars that have these quakes. Helioseismology is pretty much the only way to get a good idea of
what's going on in the interior of stars, which is vital information if we are to improve our
knowledge of the life cycle of stars, including our sun.

Kepler's primary mission will continue until November 2012, but if the spacecraft remains in good
shape, it's likely to be extended. COROT's mission was due to end about now, but has been extended
until 2013.

And finally, a bit closer to home, as well as planets, there are also minor planets better known as
asteroids. Minor planets are given catalogue numbers and proper names as well, and I see that one
of them will soon reach its closest point to earth. Asteroid 12820 Robin Williams will come within
about 300,000,000 kilometres of us on February 3rd, which is not too close, but close enough, thank
you very much.

And I see from the database that its orbit has a mean anomaly of 353. Yep, that's pretty mean. And
an argument of perihelion of 255. And yep, that's pretty argumentative. But it has an eccentricity
factor of only 0.045. That's actually quite low, so something's not right here. Oh I see, it's
Robin with an 'i', not Robyn with a 'y'. It's named after the actor. Well, that explains it. If it
had been our dear old Robyn, the eccentricity factor would've been off the scale!

Robyn Williams: I wonder what he means! I think we should be told!

Superstition

Superstition

Why do we have superstitious beliefs? Some people would not accept organs which could save their
life if they knew they came from a murderer. Why not? Our brains can play tricks on us and let us
accept ideas which have no basis in fact. Bruce Hood explores the reasons why so many people
blindly accept mystical or supernatural stories.

Transcript

Robyn Williams: Would you accept clothing from someone if you knew they were a murderer? Would you
willingly wear clothing if you knew it belonged to Amrozi or Myra Hindley or Charles Manson? Are
you in other words superstitious, as if the clothing were tainted with evil, or wouldn't you mind?
Bruce Hood has done that sort of experiment and he's also worked out that superstition is sort of
wired in when we're young as a kind of extra. We believe in the supernatural because we're trying
to make sense of the normal world.

Bruce Hood: The idea is simply that we're born with brains which have evolved to make sense of a
complex world by seeking patterns and trying to understand the mechanisms responsible for those
patterns. And in doing so, and this operates early, it's an intuitive, untutored process, in doing
so children sometimes come up with misconceptions, or assumptions which can be seen to be the basis
of later adult supernatural beliefs. So the idea is that one source of beliefs is from within the
child, not necessarily through storytelling or indoctrination. Now whether education can eradicate
these ideas is another issue, because I think that these, because they're intuitive and early
emerging, may actually be dormant in the adult and emerge at times of stress and uncertainty. So
you're almost having to fight against some of these institutions, I think, as an adult. And there
is evidence from other laboratories showing that when adults are put under stressful situations
where they have to respond quickly, or indeed if they have a degree of compromised mental function
through brain disease, they revert back to these superstitious ways of thinking. So I think it's
something that's with us, it's part of the human condition, it's almost a bi-product of the way
that our brains have evolved.

Robyn Williams: So you're suggesting it's almost built in. And what is it for?

Bruce Hood: Well, because it's a bi-product, it means that the other mechanisms which generate
their true causal understanding of the world will occasionally turn up these spurious assumptions.
So it's not for anything in particular, it's just a bi-product of a system which is designed to
interpret the world.

Robyn Williams: And so it's quite separate from something like a religious belief, a religious
tendency?

Bruce Hood: Absolutely. I think religions have successfully capitalised upon superstitious beliefs,
because they need something that goes over and beyond the verifiable evidence. They need things to
be taken on trust. They need things which have to be understood or accepted at some profound and
not mundane level. And that's why they work so well. But ultimately, religions are culturally
constructed, and transmit through storytelling and indoctrination in that sense.

Robyn Williams: So did you do a survey of secular beliefs? In order words separating out the
non-religious part of the population from the religious part?

Bruce Hood: More so actually, we've done empirical surveys. We've actually looked at beliefs about
moral contamination for example. This was an idea I talked about three years ago to you, the idea
of the killer's cardigan. I think a similar mechanism is operating in the way that we don't want to
touch objects which we think are contaminated, and we've just had a study accepted on our attitudes
towards organ transplantations from donors who we learn or discover to be morally corrupt. And not
surprisingly, people are very reluctant at the prospect of having a heart or a liver transplant
from someone they discover has been an evil murderer. Now there's a number of reasons why you might
think that, but one of the reasons I think is because it triggers this psychological essentialism.
And this is an idea that we naturally think that there's an inner property to the material or
living world that is responsible for the identity, or makes something unique. And so for example,
when we say somebody is evil to the core, we're treating evil as if it's almost physically manifest
and it could contaminate the physical organ, and that's something that could be then transmitted
into transplant patients.

Robyn Williams: Just to remind, three years we talked about whether you would actually have a
cardigan from a murderer if you were given it free, an actually wonderful cardigan, and every
reason to take it, but because it had this terrible provenance you'd turn it down. But when you
mentioned the organs being transplanted, I remember a documentary that actually said that some
heart recipients developed the characteristic of the donors. They suddenly started to write poetry
or something extraordinary. There's no evidence for that whatever, is there?

Bruce Hood: There's a lot of anecdotal evidence for that. And I would hasten to add that in fact
transplant patients do experience profound changes in their personality. Now there's very good
physiological reasons for that, if you consider that these people have been near to the point of
death and they've had to take medication and then they're given a new lease of life, it's not
surprising that they feel different and think differently about the life afterwards. But then to
attribute that to somehow incorporating the personality of the donor, there's no scientific model
that I'm aware of that could explain that. I am familiar with the documentary we're talking about.
There was a pseudo-science theory about what was called cellular memory. And indeed there were some
studies which claimed that animals which were trained to run mazes, if you grind them up and feed
them to other animals, they can then learn the maze much quicker. But these have generally been
dismissed as poor studies. So there isn't any scientific explanation for what is a common
assumption. About one in three transplant patients feel that they've taken on some aspect of the
donor.

Robyn Williams: Let me give you a complicated answer maybe that was published recently about
storytelling. And that is that we really need in a cultural sense stories really to form cultures,
to tell histories. If you go back to Aboriginal history, there are story lines that go back
thousands of years and they're combined with songs that tell you something about where you belong,
and reinforce that feeling of belonging. Now it's not surprising that if you're being imaginative
like that, that you'd have a few kind of add-ons as you said in the beginning, a few mysterious,
almost magical things. Could it be perhaps the story is the thing, rather than the supernatural
part?

Bruce Hood: I think it's probably likely to be a combination. Now Pascal Boyer and Scott Atran are
anthropologists who've been analysing the nature of stories and religious concepts and myths and
how they transmit. And what it turns out from their studies is that there are universals of certain
stories, and they have to have a degree of supernatural component to them. And these stories which
have this degree of the mystical or the fantastical, they transmit that much better, because they
trigger within us this sense of the profound, rather than it just being another kind of boring
story. So yes, you're right. The narrative is important for making sense and giving you a sense of
cohesion and connection. But this supernatural component these stories contain usually, something
about a spirit or something like that, makes them that much more pertinent. And that's why they do
so well and transmit down through the generations.

Robyn Williams: There are stories, however, there's evidence of people having perceptions. I've had
them myself, where you think you're seeing something, you know like explanation for near death
experience, where a whole number of people, not least in Harvard they've done experiments to show
that it might have been the effect on the brain of depleted oxygen or whatever, that you get
different sorts of feelings. The ergotism of the ancients, the Middle Ages, where you were infected
by fungus. I mean all sorts of ways that you can get these sorts of things, could there not be
physiological explanations that supersede those?

Bruce Hood: Well I think what you've pointed to is the fact, the common fact, that look, our lives
are punctuated by strange things all the time. There are coincidences which just seem so bizarre.
And it's how we make sense of them and how we interpret them which defines whether we're a believer
or non-believer. Yes, I do not believe in a spiritual world, and I think that for every phenomenon
there must be some natural explanation to it. It's how we interpret these phenomena which define
whether we're believers or not. And it's partly, as I've said, this inclination to make the
assumption of causal mechanisms, where there may be none in fact operating. And that's what is the
basis for the supernatural belief.

Robyn Williams: And of course some people have suggested that if there's a genetic basis, you know
lots of kids have propensity, there must be genes for it. And what about the God gene? You've
dismissed that.

Bruce Hood: Well, I've dismissed it in the same way as I dismiss that there was a gene for
Shakespeare. I mean no one would contest the issue that there are genes for language, because every
child learns a language. But the language you acquire depends on the environment in which you're
raised. In the same way, the religion that you acquire depends on the environment in which you're
raised as well. So religions are complex cultural constructed accounts of where we've come from,
how we should lead our lives and where we're going. All religions have components, universal
components, for example the notion of the afterlife or that the soul is somehow different to the
body. But these components I would contest are probably the result of the bi-products I've said
that we're born with. But that doesn't mean that a belief in religion or God is the inevitable
consequence. So yes, the components of religion have aspects which probably do have a biological
basis, but the full gamut of religion and the way it's expressed and so forth, clearly is a
cultural phenomenon.

Robyn Williams: His book is called Super Sense: From Superstition to Religion - the Brain Science
of Belief. And Bruce Hood is professor of developmental psychology at the University of Bristol.

Sherpas report glaciers going, going, gong

Sherpas report glaciers going, going, gong

Errors have been found in IPCC reports predicting when Himalayan glaciers may be no more, as a
result of rising world temperatures. These predictions are averages for large areas, and any one
location may be affected much earlier, or later, than the predicted time. Meanwhile the effects are
being felt today, as Alexandra de Blas reports.

Transcript

Robyn Williams: This week you may have heard Professor Andy Pitman talk to Sarah Clarke about
glaciers.

Andy Pitman: My personal view is that climate scientists are losing sight with the sceptics, that
the sceptics are so well funded, so well organised, have nothing else to do. They kind of don't
have day jobs. They can put all of their efforts into misinforming and miscommunicating climate
science to the general public. Whereas the climate scientists have day jobs and this actually isn't
one of them. All of the efforts you do in an IPCC report is done out of hours, voluntarily, for no
funding and no pay. Whereas the sceptics are being funded to put out full-scale misinformation
campaigns, and are doing a damn good job I think. They are doing at superb job at misinforming and
miscommunicating the general public, state and federal governments.

Sarah Clarke: You say you're losing the debate. How worried are you about that?

Andy Pitman: I think it's potentially catastrophic. If this was academic debate over some trivial
issue, so we're losing an academic debate over some trivial issue. But this isn't. This is
absolutely a fundamental problem for the earth that we desperately needed full-scale international
action on a decade ago. We're now ten years too late to stop some of the major impacts that we will
see and have seen as a consequence of global warming. It's not a future problem; it's a problem
here today around us.

Sarah Clarke: Professor Pitman, thanks very much for joining us.

Andy Pitman: You're very welcome.

Robyn Williams: Professor Andy Pitman from the University of New South Wales was talking to the
ABC's Sarah Clarke, prompted by that howler in the IPCC report on Himalayan glaciers supposedly
being gone by 2035, instead of perhaps by 2300 roughly. But the big question is whether those
glaciers are shrinking at all beyond the expected. Alexandra de Blas.

Alexandra de Blas: Nepal is a country particularly vulnerable to climate change, and its
temperature has risen at twice the global average. A unique photographic project is shedding light
on the way this warming is affecting the region. Dr. Alton Byers, a director at the Mountain
Institute in the United States, struck gold when he was given a box of photographs taken by three
climate scientists on Everest expeditions in the 1950s. Dr. Byers has since retraced their steps
and replicated hundreds of their images, more than 50 years later.

Alton Byers: I found great change. I found that certain glaciers that were glaciers back when Erwin
Schneider took his panoramic photographs are now lakes because of melting. I found other glaciers
have had such a thick cover of debris on them, they haven't receded, they haven't melted that
quickly, but they've lost volume, they've ablated. Many of the smaller glaciers, smaller, lower
altitude, not protected by debris, have been very vulnerable and hundreds of those are gone. A
glacier the size of half a football field 50 years ago is now gone. Quite disturbingly, I found
there have been 34 new lakes forming as the glaciers melt in the last 30 years or so. 22 of them
have increased in size and 11 were classified as potentially dangerous. So these new glacial lakes
that have formed are potentially dangerous to local communities and also downstream infrastructure.
And there've been historically a number of glacial lake outbursts in the Everest area, so the
Sherpa people up there are somewhat concerned about some of the ones that are growing today.

Alexandra de Blas: The Mountain Institute is working in Nepal with Dawa Steven Sherpa and Apa
Sherpa, both of whom went to Copenhagen in December to alert the world's leaders to the changes
occurring as a result of warming at the Third Pole. Apa Sherpa experienced the horror of a
collapsing glacial lake when his village was washed away in 1985.

Apa Sherpa: Everything washed down in my property, and all the neighbours, the farm land and all
property.

Alexandra de Blas: So what actually happened in 1985?

Dawa Steven Sherpa: There was a small glacial lake that was created by the receding glacier. You
know the glacier was called Langmoche and it had been melting, and as the ice melted it created a
lake. And the lake grew every year until one day a big section of the glacier that was receding
just broke off and plunged into the lake. And this created a big wave, a swell in the water, which
broke through the moraine dam. And as that happened, all the water emptied out of the lake within a
matter of hours. And all the farms down valley, they were all washed away. I mean it wasn't just
the farms and the farmhouses like Apa's, but also the forest and the bridges and the mountain
trails. This is 24 years ago. So if you go there now, even today there nothing can be grown in that
area, because all the topsoil was washed away and there's just sand and boulders.

Alexandra de Blas: Dawa Steven Sherpa has organised four expeditions to Mt. Everest and climbed to
the summit twice, while Apa Sherpa has scaled the peak a remarkable 19 times. They run an Everest
expedition business which allows them to witness the changes from both a climber and villager's
perspective first hand. Apa Sherpa.

Apa Sherpa: There's a big change. There used to be a lot of snow and a lot of ice, but now with
less snow and less ice, there is more rock, and it's more difficult to climb. It's more dangerous
for climbing. There is big change, now.

Dawa Steven Sherpa: The first thing that happens when the ice melts is that the rocks come out. The
rocks are normally glued down to the slopes by the ice, but if the ice is gone, then there's
nothing to hold it, so the rocks can tumble down. And they do tumble down. You can have more
instances of avalanches in fact, big sections of cornices that hang onto the slopes, they do break
off and then come down towards the climbers. We've had a fatality this year because of something
like that. The size of these avalanches are massive. They're bigger than most people have seen.

Alexandra de Blas: What else is being revealed as the ice melts?

Dawa Steven Sherpa: One of the things that we do on the expedition is also we do a lot of cleanup
of garbage. Old garbage from expeditions from previous decades, especially the '70s and the '80s
are starting to reappear as the glacier melts. It's sometimes like a walk through history because
you'll pick up a can which says like 1962 or a log that they used in the old days instead of
ladders, because the ice wall is full of crevasses, so to cross the crevasses they would put down
these logs. Of course with garbage and all things left behind, there are also bodies, climbers
who've perished in the mountains. Last year and this year now we've seen three bodies coming out of
the ice wall, and we expect this to happen more and more.

Alexandra de Blas: Quite disconcerting?

Dawa Steven Sherpa: It is, for a climber to see another dead climber is never a nice thing. But you
know that's part of life. We take the body off the glacier and give it a proper burial, and so
we've done this now twice. Last year we found a body of a dead British climber from the '70s. In
fact he was Australian. He was an Australian climber who was on the Bonington expedition, and so we
managed to take his body off the glacier and we buried him. And then we got in contact with his
family.

Alexandra de Blas: How much is the weather itself changing?

Dawa Steven Sherpa: We are getting more extremes of weather, so the droughts are longer now. So
last year we had a seven month drought, the year before we had a six month drought. When you don't
have glaciers to get water from, and then you also don't have rain, then you can't plant your
crops. But then when it does rain, so for example when the monsoon comes, it comes with an
extremely furious intensity, and you get landslides and you get floods. And if you do plant your
crops, your crops are either washed away or they're drowned, and so it destroys it. And the weather
patterns aren't regular like they used to be. So farmers don't know when to plant. In the old days,
it was very easy to say, this is the time to plant and this is the time to harvest. But now, you
don't know when the rains are going to come, or if they're going to come at all. And so it becomes
increasingly difficult for people to sustain their livelihoods. And many of the Sherpas up in the
mountains, many of the mountain communities in fact, not just the Sherpas, are herders. So they
have herds of yaks that they take to pasture every year. With increasing melting of the ice, the
old trails that would take them over the glaciers onto the pastures, now the glacier's gone and so
it's not possible to take the yaks over the glaciers any more. So they're losing very important
pasture lands as well.

Alexandra de Blas: How has the wildlife been affected by the fact that the temperature's getting
warmer and the seasons are changing?

Dawa Steven Sherpa: Because of the increasing temperature, we're seeing that more lowland plants
are starting to creep into the forest higher up. And we're also seeing that there's more lowland
animals such as normal spotted leopards and feral cats and wild boars moving up into the alpine
areas. And they are competing directly with the alpine wildlife, especially the snow leopard, which
are already endangered. And when the snow leopards are having to compete with these other alien
animals that are coming in, they are pushed to the limit. And so what we're also seeing is that
they're coming right into the village and starting to prey on domestic animals like dogs, cats,
cows, baby yaks, baby horses, that sort of thing. And so it's causing a friction between the local
people and the wildlife.

Robyn Williams: That report from Alexandra de Blas. Mainly eyewitness accounts there, anecdotal. In
such vast terrain, the scientific surveys take ages.

Secrets of the Southern Ocean

Secrets of the Southern Ocean

In 2007, as part of the census of Antarctic marine life, 54 scientists took a seven-week voyage on
the Australian research ship Aurora Australis to collect marine samples and data from the Southern
Ocean. Now, over two years later, Sarah Castor-Perry speaks to two scientists from the ship who
describe some of the findings.

Transcript

Robyn Williams: As we've said many times on The Science Show, warming in Antarctica can produce
increased precipitation in the form of snow following more evaporation from the sea, and so
increase the thickness of the ice in some places. Hence the need for intense coordinated
international expeditions. Sarah Castor-Perry produced this report.

Martin Riddle: Good morning everybody. I'm Martin Riddle. I'm the voyage leader for V3, the
collaborative East Antarctic Marine Census. This as you all know is part of the International Polar
Year. It's a voyage that has about 54 scientists on board, and it's part of an international
collaboration that will be happening all around Antarctica.

Sarah Castor-Perry: In 2007, ABC Radio National's Margot Foster went off on an exciting voyage to
the Antarctic on the Aurora Australis, as part of the census of Antarctic marine life and the
International Polar Year. The team spent six weeks collecting water samples, videos and samples of
sediment, and some of the animals living on the floor of the ocean. The twin aims were to find out
what sort of organisms lived in the study area, and to monitor the water temperature, salinity and
ocean currents. But what has all that data collection told them? Well, I caught up with a couple of
the scientists who went on the voyage, Steve Rintoul from CSIRO and Martin Riddle from the
Australian Antarctic Division, to find out how things have moved on.

Steve Rintoul: The International Polar Year was a fantastic opportunity for polar science, because
it meant that scientists from around the world came together to pool their resources and also to
determine what were the highest priority measurements to make, and then went out and did that in a
coordinated way. So we were able to get a really good picture of what's happening in the Southern
Ocean and in Antarctica within a single year or two. That's important because in the past most of
our measurements were scattered over time or taken in different places at different times, and it
was difficult to construct a very good picture of exactly what the state of the Southern Ocean was.

Martin Riddle: It has really opened the door on the diversity of marine life in the Antarctic. We
all knew that it was highly diverse, but we really had no idea that it would be as diverse as it
is. So a remarkable number of new species have been discovered. So this is really fundamental
natural history, new species being discovered added to the inventory of life on earth. And it's
important. We will not know what we may lose through climate change if we don't know what we had.

Sarah Castor-Perry: That was Steve Rintoul from CSIRO and Martin Riddle from the Australian
Antarctic Division, who you heard from earlier as the voyage leader on Margot Foster's trip on the
Aurora Australis. So there are two sides to the story of the V3 voyage - the biodiversity and the
oceanography. We heard from Martin Riddle that the data collected on the voyage showed that the
Southern Ocean was much more biodiverse than even the scientists thought it would be. Let's find
out why.

Martin Riddle: Well one of the driving forces of diversity is actually disturbance. Disturbance on
different timescales, on different spatial scales, creates different patterns. So you get old
growth similar to an old growth forest, places that have been undisturbed for thousands of years,
and slow growing species can grow up and dominate in those communities. In areas that are disturbed
perhaps by the keel of an iceberg, an iceberg can reach down to 450 metres and it can actually
scrape everything off the seabed, and in doing so it creates a bare pasture for new things to grow.
And so that allows for the early colonisers, if you like the weedy species, the fast growing
species, to get in. So they get in there quickly and then gradually over time the slow growing
species come through and take over. And so what we see in the Antarctic is actually a patchwork of
disturbance and variability from all sorts of different forces. Icebergs is one. Different sea ice
cover is another. So in areas which are constantly covered in sea ice, there's very little light
getting through. In areas that are generally open water for most of the year, a lot of light comes
through. So in the shallow areas where there's a lot of light, plants will grow, seaweeds will
grow. In shallow areas even down to just 20 metres which normally would be dominated by seaweeds,
if they're covered with sea ice for most of the year, then it's sponges and other things that are
more typically found in the deeper areas. So there are all sorts of different patch generating
processes, and disturbance actually leads to diversity.

Sarah Castor-Perry: And so what are you doing with the information that you got from the voyage?
And what are the implications of what you found out?

Martin Riddle: Well one of the most amazing discoveries we found down there was a really rich,
really diverse, really colourful, but very, very fragile cold water coral community. As soon as we
saw this, we could see that it was very diverse, a lot of different species living there, a lot of
fish flittering around, a lot of life, corals and sponges and things living on them and in them. So
a highly structured, three dimensional community. But also very fragile. And interestingly enough,
it was the only place throughout the entire seven-week voyage that we saw any fishing activity. So
the fishing people knew that it was rich and diverse. And they were at that site because of that.
Now the information that we got, the film footage and the samples that we had, were enough to
convince the Commission for the Conservation of Antarctic Marine Living Resources, to declare this
a vulnerable marine ecosystem. And it was the first vulnerable marine ecosystem declared in the
Southern Ocean. And CCAMLR, the Commission for the Conservation of Antarctic Marine Living
Resources, is an international body that regulates fisheries activities in the Southern Ocean. So
all of the countries that sign onto CCAMLR will now respect the protection accorded to that area as
a vulnerable marine ecosystem.

Sarah Castor-Perry: Ocean currents also play a role in determining where species can survive. When
sea ice forms, the water left underneath the ice is extra salty, because the rest of the water is
locked up in the ice. This makes the water more dense, so it sinks down to the ocean floor, up to
five kilometres down. The movement of such large amounts of water helps to drive other ocean
currents and also affects the world's weather. The sinking water takes oxygen and nutrients with it
that help to sustain life in the deep ocean. And in fact, the ocean life itself can tell us about
the direction and the flow of the currents.

Steve Rintoul: One of the surprises is that we took lots of underwater video of what organisms were
living on the sea floor, and in many places there were lots of feather stars. These animals catch
food by sticking their arms out across the current. And when they filter something out of the
water, they then move food into their mouth. We found that we can actually use the orientation of
the feather stars, because they tend to orient themselves across the current so they can catch more
food. We can tell the current direction by looking at the orientation of the feather stars. So
we've actually been using the starfish to map bottom current directions around the Antarctic shelf,
which is something we've never thought of trying before.

Sarah Castor-Perry: What sort of information does that give you? The direction of the current?

Steve Rintoul: One of the key things that we're trying to discover is what the pattern of ocean
currents is over the Antarctic shelf, and how that helps determine how much dense water forms and
is exported from the shelf to the deep ocean. So the first thing we need to determine is what the
pattern of ocean currents are. And that's not so easy to measure from the ship. But the fact that
we can tell what direction the currents near the bottom are going from the orientation of the
feather stars provides us with another piece of information that we can combine with what we
measure from the ship to develop a picture of what the pattern of ocean currents is over the
Antarctic shelf.

Sarah Castor-Perry: Steve Rintoul from CSIRO's Marine and Atmospheric Research in Hobart.

Steve Rintoul: During the trip we went back to locations where we made measurements before, dating
back to 1991. We went back to those same places, measured temperature and salinity and oxygen
again, and compared it to earlier measurements. And what we're finding is that there's a layer of
water near the sea floor that's steadily becoming fresher over the last couple of decades. It's
becoming lower in salinity and less dense. This water's important. It's called Antarctic bottom
water, and it's only formed in a few locations around the edge of Antarctica where the conditions
are right to make surface water so dense that it can sink from the surface of the ocean down four
or five kilometres below the sea surface. And what we're finding is that that layer's becoming
fresher, lower in salinity. And we think the cause of this is that glacial ice as it flows off the
continent of Antarctica and into the ocean is starting to melt more than it used to. And that fresh
melted ice is mixing with the waters around Antarctica and causing the signal that we've been able
to pick up in our measurements.

Sarah Castor-Perry: And what would the expected effects of the increasing freshness of the water
be?

Steve Rintoul: What it does indicate to us is that even the deepest layers of the ocean are
sensitive to changes in high latitude climate. And they can respond very quickly to changes in that
climate. We also know that during past periods of earth's history, when waters around the poles had
become fresher, they became so fresh and so light that it shut down that sinking process. And shut
down a global pattern of ocean currents that we call the overturning circulation. That circulation
is the main way that the ocean carries heat and carbon dioxide and other properties around the
globe, and thereby influences climate. So we're not seeing a slowing down of that process yet, but
additional fresh water being added by melting ice is shifting things in that same direction. So
it's something we need to keep an eye on, so we can detect if changes are going to happen in the
future, like those we observed in different periods in the past.

One of the disadvantages of making measurements from a ship is that we only obtain observations
when the ship happens to be there, and often that's during the summer because there's less ice
around and so it's easier for the ship to operate. But to really know what's happening with this
bottom water production, we need measurements from the winter. So during the voyage we left some
instruments anchored to the sea floor to measure temperature, salinity and ocean current
velocities. And we came back a year later on a French ship and recovered them, so that was the
first exciting thing.

And what those measurements have shown us is that during the winter there are intense pulses of
very cold and relatively salty water that are flowing off the continental shelf around Antarctica
in a sort of waterfall or intense river carrying this water off the edge of Antarctica, right down
into the deepest layers of the ocean. We've never been able to measure that process before, so it's
very exciting that we've now made direct measurements of exactly how much water is flowing off the
shelf, information that in the past we've had to try to infer from indirect measurements, for
example the temperature or the oxygen levels.

Sarah Castor-Perry: So there haven't been any major changes in salinity levels yet, but something
that is already changing is ocean acidity.

Martin Riddle: The Southern Ocean and the animals that live there are really in some senses the
sentinels, the early warning of change that we will see in other parts of the planet. And perhaps
the most pressing example of this is ocean acidification.

Sarah Castor-Perry: Are we already seeing the effects?

Martin Riddle: We are certainly seeing measureable changes in the shells of some marine organisms,
so sea butterflies or terapods, these are planktonic molluscs, have a shell, and these shells are
sensitive to the acidity of the water. And what scientists have shown is that old shells, shells
from the pre-industrial era that we can take from sediments, have slightly heavier shells than
modern terapods. So yes, we are seeing the early signs of this. And perhaps the most worrying thing
is that the modellers are indicating that a critical threshold of pH will actually reach the
surface of the Southern Ocean in winter time by 2038. So that is not very long.

Sarah Castor-Perry: The coral reefs and other marine communities in the Southern Ocean are more
vulnerable than their counterparts in warmer seas like the Great Barrier Reef. This is down to a
simple piece of school chemistry - gases dissolve better in cold water. The CO2 in the atmosphere
will dissolve into the water at the poles more easily than in warmer waters, making the cold seas
more acidic first. If this critical acidity threshold does reach the surface, it will mean the loss
of those fragile coral communities, and could foreshadow what we could see happening to marine
ecosystems closer to home in the future. But it's not just corals and plankton that will be
affected. Krill are hugely important in many ocean chains and they also need carbonates to build
their shells. Rob King from the Australian Antarctic Division works on Antarctic krill, and has
shown that high acidity stops their eggs from hatching properly. He explains that we know increased
acidity will be a bad thing for the krill, but we just can't be sure how great the wider effects
will be.

Rob King: Well, it would just be a massive change. I mean, particularly in the Antarctic ecosystem,
because krill really are the keystone species there. So many animals depend on krill. A blue whale
can take up to a tonne of krill in a mouthful. I mean that's the reason that whales want to swim
all the way down to Antarctica each year to go feeding. They gorge themselves on krill. But it's
not just these big charismatic mega fauna. It's all of the little creatures down there that are
relying on krill. And it's not just a one way street. I mean the nutrients that go to feed the
fighter plankton are partly coming from the excrement of krill. We have to remember that ecosystems
don't just go from little to big, but the stuff that the big guys are doing are going back the
other direction as well.

Sarah Castor-Perry: And spotting those migrating whales was one of the high points of the voyage
for Steve Rintoul.

Steve Rintoul: There were some really incredible moments during the trip. At one point the ship was
stopped and we were making some oceanographic measurements. And we saw some whale spouts quite a
ways off. It was a very calm day and the whales swam a couple of kilometres straight to the ship
and passed directly underneath where we were standing on the edge of the ship. And it was a mother
humpback whale and two calves that then spent the entire three or four hours when we were making
our measurements just swimming round and round the ship, and breeching and waving their flippers
and flukes, and it was really a beautiful experience.

Sarah Castor-Perry: They found huge diversity of life, but also fragility in the systems. The
chemical changes being seen already in the Southern Ocean could spell disaster for many species,
and could be an early warning of the fate that awaits other marine ecosystems, like the corals of
the Great Barrier Reef. As Steve Rintoul explained, international collaborations like the
International Polar Year and the Census of Marine Life, are important. They help to provide
scientists around the world with the information to see large scale, long term patterns. Hopefully
a greater understanding of the animals and how they interact with their marine environment will
allow us to prepare for the changes ahead, and help to reduce the damage.

Robyn Williams: Sarah Castor-Perry on the massive research findings coming out of the International
Polar Year now ending.

David Attenborough - Why humans sing

David Attenborough - Why humans sing

Evolutionary theory says that physical characters develop because they're needed. Birds sing to
advertise sex. But what is the need for humans to be able to sing as we do? David Attenborough
describes some of the animals which have complex song and seeks to explain why humans sing and are
attracted to song singers and music.

Transcript

David Attenborough: The human voice is very odd. I'm not thinking about its ability to produce
yelps of pain or threatening roars or even to communicate with speech. I'm talking about singing; a
tenor producing an eye-popping and hair-raising high E, a soprano executing perfectly articulated
runs and trills, or come to that, several thousand well lubricated throats in the National Stadium
in Cardiff singing together and in harmony, Bread of Heaven.

Evolutionary theory maintains that physical characters develop because they're needed, because they
bring their owner an advantage. But what need was there for the human throat to have evolved a
larynx that can produce such pure, musically accurate sounds, over such an astonishing range?
Whatever that need, it must have existed a very long time ago to allow such a complex anatomical
device to develop. It may even have existed among our far distant humanoid ancestors even before
our species, Homo sapiens, appeared on earth.

Human beings of course are not the only creatures that sing. Birds do. And again, I'm not thinking
about the chattering notes of an outraged blackbird or the harsh, aggressive squawks of a magpie.
Such vocalisations carry simple messages; look out, there's danger, or this is who I am and this
plot of land is mine. No, I'm talking about real song, sustained, complex and melodic.

The songs of birds have characteristic scales, durations and intervals that enable you to identify
the species of the singer. They may also defer sufficiently in their details for even a human ear
to recognise a particular individual. It's likely to be a male, for the song is an essential part
of his courtship. Birdsong is connected with sex.

Interestingly, there seems to be a rough relationship between song and plumage. The more visually
stunning the bird is, the simpler and often the harsher its call is likely to be. So when you see a
parakeet, resplendent in green, blue or dazzling scarlet, you can predict before it even opens its
beak that it'll make a harsh sound, and one so simple it could hardly be described as song.

Nature seldom goes in for belt and braces, so you might well guess that the display of bright
feathers and the carolling of a complex song are alternatives, different ways of achieving the same
goal. Both have a sexual purpose. Both are ways by which a male bird attempts to persuade a female
to mate with him rather than with a rival.

There is a famous, if somewhat unfeeling experiment that was carried out on the African widow bird.
It lives in the grasslands of Kenya. Out of the breeding season, both sexes look rather like large
sparrows. But when the breeding season arrives, the male grows black feathers and a long, glossy
black tail, and sets up his territory amongst the tall grass. The experimenters caught a range of
these males. They shortened the tails of one group, so that they were only about six inches long.
Then they added those cut pieces to the tails of another group, so that their tails became about
twice the normal length. And yes, it really did work as you might have predicted. The trimmed males
postured with just as much self-confidence and bravado as before, but found themselves largely
ignored; while on the other hand those with lengthened tails found themselves overwhelmed by female
admirers.

Well, song is the audio equivalent of the widow bird's tail. The longer and more complex it is, the
more successful it is. The most dramatic proof of that that I know has been produced by a group of
Swedish ornithologists working with great reed warblers. These birds are summer visitors to Sweden.
First to arrive in spring are the males. Each established a territory for himself in the reed beds
by singing duels.

The birds are so pumped up with testosterone that these duels can go on, one after the other, all
day, which here in the north at this time can last for 20 hours. The songs at this stage are
relatively simple. Each contains a number of different syllables between 10 and 15, which are
produced in varying combinations. By duelling in this way, the males space themselves out in more
or less evenly spaced territories across the uniform expanse of reeds. And then a week or so later,
the females arrive from Africa. And immediately the males change their calls from signals into
songs - longer, more sustained and more varied.

The females tour the territories listening to different males. To our ears, the song of the
different males may sound very similar. But if you record them and slow them down, you can count
the different syllables that any one song contains. And they vary quite considerably. Good
performers can produce songs that contain 45 syllables; bad singers only 25. And a female, when
given the choice, invariably mates with the one with the more syllables.

And what about mammals? Do mammals, apart from human beings, have songs? Well, there is one group
which really does produce songs that in melodic invention, excitement and complexity outshine all
rivals except mankind. You're likely to hear it before dawn, ringing out over the canopy of the
forests of the Far East. And once heard, never forgotten. It is of course the song of the gibbon.
There are a number of species of gibbon and they all sing. A young male having left his family
group to start life on his own usually gives a solo recital in the early mornings. It can last for
as long as a quarter of an hour and can be heard over half a mile away. Young females on the other
hand don't sing at all. But they're clearly attracted by the male's song. I don't know of any
studies that have been done analysing the different skills of individual young males, but I
wouldn't mind betting that they do vary, and that the female gibbons, like the female reed
warblers, are discerning critics. It may well be that the fitter, the stronger and healthier a male
gibbon is, the better he sings. But I don't believe that the females say to themselves, that's a
wonderful, powerful, inventive song and therefore I will mate with the singer, for my offspring
will be stronger and healthier than if I mated with a less talented singer. No. She's simply
beguiled by his singing. She has in fact a very real sense of musical appreciation. So when she
hears a really accomplished singer, she's delighted and she joins him. Singer and listener don't
always click immediately. The male may have one or two liaisons, but eventually the two form a pair
bond. And now she sings with him. They duet.

They practice singing together, working out the details of their duet, until they've created an
elaborate composition that is personal to them. It starts with a warm-up in which the male and
female exchange short phrases. But then usually the female takes over and embarks on a magnificent
solo aria, her great call, to which the male may add encouraging interjections, until finally the
two of them join together in a wildly passionate climax, whooping and calling, as they fling
themselves to the branches high in the canopy of one of their favourite trees. The whole
performance may last for a quarter of an hour.

In due course, after an eight month pregnancy, the female gives birth to a single baby. It will
remain dependent on its parents for some considerable time, and be still with them when a second or
even a third child arrives. As their parents continue with their music making, so the older among
the young may join in. Singing, it seems, not only creates a family in the first place, but is
instrumental in keeping it together even when the young arrive.

It's tempting to think that human beings very early in their history used music in a similar way.
And there can be little question that a male with a good singing voice in our own society today is
still a source of sexual attraction and excitement. What else is a serenade? Watch a pop concert!
And just as among the great reed warblers, quality counts. Females have been selecting males with a
versatile larynx since way back in our ancestry.

Today young men sing together to generate camaraderie, and religious people use song to generate
the deepest and most profound emotions among themselves and their listeners. But the prime function
of song is something else. Shakespeare wondered if music was the food of love. Well, vocally at
least, it certainly was. And what is more, it still is.

Robyn Williams: Sara Macliver and Sally-Anne Russell singing from Bach's Christmas Oratorio.