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00:00Thank you for listening.
00:30Thank you for listening.
01:00The world of fresh water.
01:14At first sight, a lake like this would seem to have everything
01:34that life needs in order to thrive.
01:38Clear, oxygen-rich water, plenty of dissolved nutrients and minerals
01:43and lots of sunlight.
01:45But in fact, life in fresh water presents plants with huge problems.
01:54To succeed, plants have had to abandon many of the adaptations
02:02that served them so well on land and evolved something quite new.
02:08And in doing that, they have created some of the most beautiful
02:13and bizarre and important habitats on Earth.
02:17There are a few places where it's more difficult to make a permanent home
02:27than a freshwater torrent like this one.
02:30Violent currents rip across the riverbed, scouring it clean.
02:57Ripping land plants from their margins and drowning them.
03:08How could any plant survive in a place like this?
03:16Yet even here, some do manage to quite literally hold on.
03:34They can grasp the bare rock with remarkable strength.
03:43This ability allows plants to thrive in these otherwise hostile environments.
03:55This ability allows plants to thrive in these otherwise hostile environments.
03:59This is the Caño Cristales River in Colombia.
04:05These plants are Red Macarenaia, sometimes called the Orchid of the Falls.
04:28They cling to the riverbed, not with their roots, but with their stems,
04:42glued to the rock surface by one of the most powerful adhesives in nature.
04:47The rock itself will break before these anchors lose their grip.
04:59These feathery filaments are their modified leaves, and they do what roots normally do,
05:18gather the minerals and nutrients they need that are dissolved in the water.
05:26With such spectacular colors, it's hardly surprising that the Caño Cristales is sometimes called
05:36the most beautiful river on Earth.
05:46But being rooted to the spot is not always the best strategy for living in a water world.
05:55This is a water lettuce, and it has some remarkable adaptations.
06:03It's roots hang free, so it's not anchored to the ground.
06:09And its leaves are thick and spongy and covered in fine hairs, so that the plant itself is more
06:17or less unsinkable.
06:27This combination of characteristics enable the water lettuce to do something that almost no
06:33land plant can do.
06:36It can travel.
06:41It is an ability that becomes invaluable when, during the wet season, flooded rivers become
06:48great highways, as they do here in South America.
06:58This is the largest inland water world on Earth, the Pantanal.
07:05For a few months every year, it provides water plants with ideal conditions.
07:12But all too soon, it becomes a battleground.
07:25The roots are racing to claim their space on the surface.
07:31The water lettuce rapidly expands its network of hanging roots, so that it starts absorbing
07:37nutrients before other competitors arrive.
07:44water hyacinth appears.
08:03Its leaves are carried on stalks filled with air that also make it virtually unsinkable.
08:10The race for space intensifies.
08:21A new competitor arrives, Ludwigia.
08:25It spreads by developing a chain of tiny rafts, and jostles the space with the densely packed
08:33leaves of mosaic plants, or are racing to claim as much sunlight as possible.
08:50They flower quickly, before the floodwaters recede.
08:59And these surface dwellers also have competitors.
09:17Including one that has been waiting in the depths, and is now stirring.
09:26It's a monster.
09:35It's a monster.
09:36It's a monster.
09:39It's a monster.
09:45It's a monster.
09:55It's a monster.
10:01It's a monster.
10:05It's a monster.
10:09It clears space for itself by wielding one of its buds like a club.
10:31And now it dominates the surface.
11:01This is a leaf of the giant water lily.
11:25It expands by over 20 centimeters a day and eventually measures more than 2 meters across.
11:38Its immense leaves are supported by a network of air-filled struts and protected by spines
11:452 centimeters long.
11:52The leaves float high in the water and their surfaces are dotted with tiny holes, drains,
11:58that help them ensure that rainwater doesn't accumulate and sink them.
12:17Nutrients from the fertile mud below are carried up by tubes in its stem to fuel the leaf's
12:24expansion.
12:33Over the next few months, the lily will produce some 40 or so of these gigantic leaves.
12:50And as each one reaches the surface and expands, more and more light is taken from those plants
12:57that are trying to grow beneath.
13:12The predators are pushed aside.
13:39They are crushed or secured.
13:46The areas of the portal are closed-to-to-to-government.
13:53And the trees are crushed.
13:56The animals are crushed and the leaves have bodies above all the knobs.
13:59They are crushed and the berries are crushed.
14:01They are crushed by the leaves.
14:03The fibers are crushed by the leaves.
14:05Eventually, its immense leaves press their margins against one another,
14:26totally cutting off the light from the plants beneath them.
14:29The battle is over, and victory is total.
14:38The frozen water world of Lake Akan in northern Japan.
15:02Home to one of the strangest and most primitive of plants.
15:10It's an alga, like those that appear so mysteriously in our ponds.
15:23But this one is truly extraordinary.
15:32Each spring, the melting ice releases soft, velvety balls of interwoven threads called marimos.
15:42This one is small, no bigger than a walnut.
15:49But there are lots of them here.
15:56They attract the attention of visiting hoopaswans.
16:02And hoopaswans.
16:32But there is one way for the marimos to escape from the danger, and it depends on a change in the weather.
16:44Fortunately, in the spring, winds sweep across the lake, creating currents that carry some of the marimos beyond the reach of hungry swans.
16:57It's the start of a remarkable journey.
17:04They are gently carried back and forth by the currents, so that the marimos begin to escape.
17:22They are gently carried back and forth by the currents, so that the marimos become more and more spherical.
17:36And slowly, they travel into deeper water.
17:39Here, there are great numbers of them, certainly many millions.
17:59Some are the size of basketballs.
18:01They are safe from swans, and the water is still shallow enough for some sunlight to reach them.
18:16It seems a perfect home.
18:19And so it is.
18:22Almost.
18:23The snag is that these waters also carry a fine sediment that can clog the marimos' surface, cutting off the all-important light.
18:38But the marimos are not entirely immobile.
18:41They dance.
18:42The winds blowing over the lake's surface create currents beneath that are sufficiently strong to move the marimos.
18:59They rub against each other, and in just a couple of hours of gentle movement, they're all clean once more.
19:00They rub against each other, and in just a couple of hours of gentle movement, they're all clean once more.
19:04And so...
19:05They make a sad
19:26As they spin, every part of their surface gets enough time in the sunlight to keep growing.
19:56This is the heart of the Amazon.
20:18There are water worlds here that are so remote that even today few people have ever seen them.
20:26This barely explored tributary is the Rio Claro.
20:33And here, when conditions are just right, it's possible to witness a rare and remarkable spectacle.
20:51The river is so crystal clear that its bed is bathed in sunlight.
20:58The magical landscape of miniature mountains and valleys.
21:05It's carpeted by pipewort, fanwort, and star grasses.
21:12It's carpeted by pipewort, fanwort, and star grasses.
21:19As the sun climbs in the sky, bubbles of gas appear.
21:26Evidence of photosynthesis.
21:33Evidence of photosynthesis.
21:40Deep inside the plant cells, tiny structures called chloroplasts move towards the light.
21:47They absorb carbon dioxide and use the sun to be exposed to the sun.
21:54They absorb carbon dioxide and use the sun to be exposed to the sun.
21:57They absorb carbon dioxide and use the sun's power to synthesize the sugars that the plant needs to grow.
22:04And, as a by-product, they release oxygen.
22:11The gas that we, and all other animals, must have in order to breathe.
22:18The gas that we, and all other animals, must have in order to breathe.
22:24The gas that we, and all other animals, must have in order to breathe.
22:54Now, in late afternoon, bubbles of oxygen make the river water fizz, like champagne.
23:24Now, isn't this dry for snot bees, you will only be used by a river water fizz, like smoke and gas, like this is where it's coming from.
23:39You as beautiful as some stories of the earth, i.e.
23:43The plants can become so buoyant with gas that they rise to the surface, even carrying
24:05the bedrock with them.
24:18Only in this remote water world can this spectacular natural wonder be seen.
24:34In Venezuela, here rectangular table mountains known as Te Puy stand above the tropical forest.
24:50There are more than 50 such isolated mountain plateaus here, each home to a unique community
24:56of plants.
25:02Landpores are so torrential that no soil can accumulate on their broad rocky summits,
25:08and some plants living up here have to find their nutrients from another source.
25:17These are bromeliads.
25:24Their leaves are shaped like a funnel and collect grain water which accumulates in the center.
25:36This small pond is colonized by all kinds of tiny animals.
25:45And it is their bodies when they die that provide some of the nutrients the bromeliads need.
25:51This makes a good partnership in which both parties can thrive, but it can be exploited by a plant predator.
25:58This makes a good partnership in which both parties can thrive, but it can be exploited by a plant predator.
26:13This makes a good partnership in which both parties can thrive, but it can be exploited by a plant predator.
26:20This probing stem belongs to a plant called a bladderwort.
26:27This probing stem belongs to a plant called a bladderwort.
26:35It too is in need of nutrients.
26:54And a well-stocked bromeliad pool is just the place to find them.
27:07This one is full of aquatic animals.
27:13The bladderwort begins to change.
27:41The bladderwort begins to change into a hunter.
27:51It develops bladders and removes sufficient of the water within them to create a partial vacuum.
28:04Each bladder has a trapdoor beside it with trigger hairs.
28:10Now, all the bladderwort has to do is to bite its time.
28:17It only takes one touch.
28:18For the trapdoor to snap open...
28:22and suck in its prey.
28:23It only takes one touch.
28:25For the trapdoor to snap open...
28:29and suck in its prey.
28:30It's all over in a millisecond.
28:34It's all over in a millisecond.
28:35It's all over in a millisecond.
28:39It's all over in a millisecond.
28:40It's all over in a millisecond.
28:46It's all over.
28:47It's all over in a millisecond.
28:53It's all over in a millisecond.
28:54It's all over in a millisecond.
29:00And after it is fed, a bladderwort has enough energy to produce another tendril to search for another bromeliad pool.
29:19So several plants that live in such places catch insects too, if they can.
29:46The leaves of sundews are covered with long red hairs, each tipped with a droplet.
30:15These glistening globules are, in fact, glue.
30:31Once the sundews detect the taste of their victim's body, they flood it with digestive enzymes.
30:57The little body disintegrates, and the sundew gets the nutrients it needs.
31:24Another plant has an even more elaborate way of cattle a meal.
31:29The Venus flytrap has leaves that are lined with interlocking teeth.
31:36It attracts insects by producing a sweet perfume, just as a flower does.
31:38It, too, has a hair trigger.
31:39It, too, has a hair trigger.
31:45And another insect is caught.
31:46And another insect is caught.
31:47And another insect is caught.
31:48And another insect is caught.
31:49And another insect is caught.
31:50And another insect is caught.
31:51And another insect is caught.
31:58And another insect is caught.
31:59And another insect is caught.
32:05And another insect is caught.
32:12But the technique is more complex than it might seem.
32:30The Venus flytrap has a problem.
32:37It needs to avoid false alarms.
32:40Snapping shut on something inedible, like a raindrop or a little bit of twig.
32:47That would be a waste of both time and energy.
32:51So how does it avoid that?
32:54Well, it does it by counting.
32:57If I touch this one, sensitive hair just there, no reaction.
33:06That could be a false alarm.
33:08But the plant remembers that for 20 seconds.
33:12And if I touch it a second time within that time, then that's much more likely to be worth eating.
33:20And so it closes.
33:25So far, so good.
33:30But now it needs to be absolutely certain that it's got something worth eating.
33:35So it continues counting.
33:38Only after it has totted up five separate touches to those hairs will it give the final squeeze.
33:47And then begin to produce the liquid from the surface of the leaf, which will dissolve the body of its unfortunate victim.
33:55The flytrap now has enough energy to produce flowers and attract pollinating insects.
34:16Wind and insects between them pollinate virtually all land plants.
34:22But neither method can be used by plants that live entirely underwater.
34:28So some lead double lives.
34:34A chalk stream in southern England and swaying in the current is a plant for which these rivers are famous.
34:43This is water crowfoot, a kind of aquatic buttercup.
34:48For most of the year, it is underwater.
34:51And if I take this underwater camera, you can see its floppy stems grow horizontally.
35:03That reduces the risk of being swept away by the current.
35:09But each spring, when it's time to flower, it produces something crucially different.
35:15A stem that is stiff enough to resist the current and lift its flowers into the air above.
35:25And now, of course, they can get help from insects.
35:49So every year, in part at least, water crowfoot becomes a land plant.
36:11A land plant.
36:12And provides us with one of the loveliest natural spectacles of the early English summer.
36:30Water crowfoot is not the only water plant to lift its flowers above the surface.
36:42Plants do so all around the world.
36:50From the swamps of the Pantanal, to the lakes of Thailand, they all burst into spectacular bloom.
37:15Once they've been pollinated, they produce seeds.
37:31And now their flowers have done their job.
37:34Some return to a life underwater.
37:44Now they must ensure that some of their seeds will find suitable places in which to germinate.
37:52They're all whoamomonas.
37:53The other east will find help from theумen and the wild, expansive wilderness are usually
37:54true in the landscape of pastalus.
37:55By which to germinate the river, the river, the river, the river, the river, the river, the river,
37:59the river.
38:01Those were the rivers of the river, the river, the river, the river, the river.
38:05All right, that's all.
38:06It's called a river.
38:07Bullrushes, every year, produce these long, brown, velvety objects.
38:14Look what happens when I break one open.
38:16open. It contains almost a quarter of a million seeds.
38:32Each seed is attached to a delicate parachute.
38:36Even the slightest breeze will lift it and may carry it for very long distances indeed.
38:49So even though suitable stretches of fresh water are few and far between, there's a good
38:58chance that at least one will end up in a place where it can grow.
39:02Much bigger seeds, of course, can't travel by air.
39:14A river can provide transport, but it's a one-way journey, downstream, that often ends up in
39:31the sea. And that's not ideal.
39:40So how can any riverside plant avoid this and travel upstream?
39:47Here, along the Bonito River in Brazil, a variety of trees manage to do exactly that.
39:59They embed their seeds in the middle of soft, sweet fruit.
40:11Monkeys, such as these capuchins, make a meal of them just as soon as they're ripe.
40:23But monkeys, such as these capuchins, make a meal of them just as soon as they're ripe.
40:35But monkeys are very wasteful feeders. And what's not eaten ends up in the river and is washed
40:46away. And it's washed away. But not all.
41:05In the fruiting season, hundreds of Piraputanga fish gather beneath these trees.
41:30But the Piraputanga want more than the monkeys' leftovers. The brightly colored fruits are
41:47clearly visible even to the fish in the water below.
41:55And some manage to claim them even before a monkey does.
42:02This isn't a skill mastered by just one particularly successful acrobatic fish. Many are the
42:22Piraputanga can do this. Nor is this a disaster for the tree. Far from it.
42:29These Piraputanga are migratory, heading many miles upriver to spawn.
42:36These Piraputanga are migratory. Far from it. Far from it.
42:43These Piraputanga are migratory, heading many miles upriver to spawn.
42:51The trees, by enticing the fish to eat their fruits, have a perfect means of transport for
42:54their seeds. With luck, the seeds will be deposited many miles upstream.
42:58The trees, by enticing the fish to eat their fruits, have a perfect means of transport for
43:05their seeds. With luck, the seeds will be deposited many miles upstream.
43:13With luck, the seeds will be deposited many miles upstream.
43:36The ability to colonize new habitats has allowed one group of flowering plants to venture out
43:43of fresh water and into a world that may look the same to us. But for a plant is crucially different.
43:55The much greater, saltier world. The sea.
44:04This is a fruit from one of the most important plants on the Earth today. Seagrass.
44:11This particular one is floating off the coast of Formentera in the Mediterranean.
44:26A hundred thousand years ago, a seagrass seed like this sank to the sea floor just here.
44:45And eventually it produced a great meadow. A meadow that is still flourishing today.
45:15It did so by cloning itself. Now over ten miles across, it's not only one of the largest
45:28living organisms on Earth, it's also one of the oldest.
45:33And it supports a rich community of many kinds of animals.
45:50It's become a kind of marine savannah.
45:59Over a thousand species now live here. Some, like these elegantly camouflaged pipefish,
46:06live nowhere else but amongst the sea grass.
46:09Seagrass fringes many of the world's coasts.
46:23Turtles depend upon it too.
46:38And so do dugong, animals that are sometimes called, very appropriately, sea cows.
46:44Today, seagrass plays a critical role in maintaining the health of our planet.
47:01It creates stores of carbon around its roots at an enormous rate.
47:0535 times faster, in fact, than plants that live on the floor of a tropical rainforest.
47:16Here, off Formentera, it's possible to see beneath the living seagrass layer upon layer of trapped carbon
47:23carbon that the plants have accumulated over the past 2,000 years.
47:35Seagrass, however, is easily destroyed by human disturbance.
47:40A third of the world's underwater meadows have already been lost,
47:44and many more are in decline.
47:54Biologists are now striving to not only protect the remaining meadows,
47:59but to restore them.
48:04One plant at a time.
48:14Seagrass could be a valuable ally in our fight against climate change.
48:19Today, water worlds everywhere are under threat.
48:34Many of their inhabitants are disappearing without us even being aware of their existence.
48:39The plants that grow in water are probably the least noticeable.
48:52They're certainly the least studied.
48:55But the more you know about the problems of living in that way,
48:59the greater the wonder of their success.
49:01Surely, they deserve more of our attention and, most importantly, our care.
49:09This vast wetland is the Pantanal.
49:14The water worlds team are heading to a plant battlefield.
49:19The home of Brazil's giant water lily.
49:22This is like seeing the end of a war.
49:23There are leaves growing on top of each other.
49:24Flowers going through leaves.
49:25Unbelievable.
49:27To capture this story in all its detail would take over.
49:29The water worlds team are heading to a plant battlefield.
49:35The home of Brazil's giant water lily.
49:39This is like seeing the end of a war.
49:44There are leaves growing on top of each other.
49:46Flowers going through leaves.
49:47Unbelievable.
49:48To capture this story in all its detail would take over a year.
49:57And require a unique green planet approach.
50:00Both filming here and in a parallel mini Pantanal.
50:05In deepest, darkest, Devon.
50:11This is the unique world of specialist time-lapse cameraman, Tim Shepard.
50:16Tim has the reputation of being able to think like a plant.
50:25It's absolutely crucial that you get the plant really happy.
50:30And to make the giant lily field totally at home,
50:33Tim must build a little piece of Brazilian wetland.
50:39First, a 10,000 litre tank.
50:41Hundreds of bricks.
50:46Almost a thousand kilos of soil.
50:49And countless cups of tea later.
50:52The foundations are complete.
50:56So far, so good.
50:58Now, time to prepare for the new green planet camera system.
51:02That way, we're trying to assemble the main gantry framework.
51:07So that we can mount the moving rig on top of it.
51:10So it's a bit of a fiddle to get all the screws in all the right place, basically.
51:16After a few weeks, the building works are complete.
51:19The flood can now begin.
51:30Tim needs to be sure everything in the room is heated to tropical temperatures.
51:35Before the star of the scene can move in.
51:45Carefully grown at the Royal Botanic Gardens at Kew, especially for us.
51:51Everything depends on this one plant.
51:59There will be no time for a second attempt.
52:04And even more important for Tim, to keep his guests happy and healthy.
52:09This big monster needs a lot of feeding.
52:13We found we need about five sandbags full of compost every two or three weeks.
52:19So we just sort of lower them in and stick them down by the roots.
52:23There we go.
52:25Whilst the Devon giant settles in, the Pantanal crew are continuing to get their shots.
52:33Time to see some giant water lilies underwater.
52:36And I hope there's no anaconda.
52:46Whew! Mission accomplished.
52:52The pressure is now on Tim.
52:57After months of pampering, the giant lily is ready for action.
53:01First thing to film is a leaf spike rising up from the depths.
53:11Luckily, there are no anacondas here.
53:16The special camera weighs over 40 kilos.
53:20It's suddenly become less heavy, which is good.
53:22The new rig means Tim will be able to follow the emerging plant in any direction.
53:27Whoa! Fancy!
53:37The technology is working well.
53:39But nature is starting to derail Tim's plans.
53:44Really tangled up with all these weeds.
53:45What happens is we've got a bit of an ecosystem developing here.
53:52Before you know it, you get masses and masses of algae growing in amongst it all.
53:57We've got to just release some anaerobic gases there.
54:04They're not me, they're the algae.
54:08State-of-the-art tools help keep the algae at bay.
54:12Keep the algae at bay!
54:17Yeah, you do!
54:25Just in time for Tim to film liftoff.
54:28That's quite nice, coming out of water, look at that.
54:44Tim Stokers can now shift to the battle that's starting to take place on the surface.
54:48I'm trying to film this new bud coming out on this lily leaf, it'll take about three
54:57days to grow from where it is now, somewhere in this zone between these two other leaves.
55:02I want that to last about ten seconds.
55:05Ten seconds is about 250 frames, that works out about one frame maybe 20 minutes.
55:13But plants don't read scripts.
55:16It's nature, it doesn't always do what you think it's going to do.
55:26We've had a few full starts where the leaf has swung out of shot and gone somewhere else.
55:37Or it just grows a lot quicker than you thought.
55:43It's a challenge to get things right, but with the combination of Tim's expertise and the
55:48new camera system, results are starting to look good.
55:52I think the difference now with this series is we can bring the plants much more to life
55:58as characters and tell their story in a much more dynamic way.
56:05It's great to be able to follow them around much more in the way you'd film an animal behaving.
56:20These rigs have given us a whole new realm of possibilities.
56:25After over a year of filming and recording a hundred thousand separate images, the secret
56:30life of the giant water lily and the battle of the Pantanal has been revealed.
56:39Next time on the Green Planet, the ever-changing seasonal world, full of hunters, tricksters, and unlikely alliances.
56:54Plants here are in a race against the clock.
56:58The timing is everything.
57:07The Open University has produced a poster that explores the vital role that plants have for
57:14our planet.
57:15To order your free copy, call 0300 303 4200 or go to bbc.co.uk forward slash green planet
57:27and follow the links to The Open University.
57:31You can hear David's guide to the green planet with music from the series, a mindful mix
57:38on the BBC Sounds app now, and including one of the finest classical actors, Anthony Scherr,
57:44who died last month, Henry IV, over on BBC Four now.
57:49Next here, a homeless man in desperate need of help on Call the Midwife.
57:52.