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Episode 1: Pulse - Preview

How did water become the essential force behind all life? Dive in!

PULSE (Hour 1) opens on the distant rock and ice of Greenland, where Geologist Stephen Mojzsis reveals a new theory on how water first arrived on Planet Earth. We see a dragonfly’s incredible journey from India to Africa – the world’s longest insect migration. We meet the Munoz family, ‘bloom chasers’, who use cutting edge time-lapse rigs to show the rare spectacle of deserts around the world exploding from barren wastelands into rich carpets of flowers. But the pulse is under threat.

H2O: The Molecule That Made Us is a 3-hour series from WGBH Boston premiering on PBS.


Probably because I use it every day, I take water for granted. I’m Kelly McEvers, and I’m a radio journalist.

And, for this story, I have teamed up with filmmakers and scientists to make a podcast-style documentary… About what might be the most important substance on our planet… water. And since embarking on this journey, I am now starting to see this molecule everywhere. We call it the water lens.

Look through it and you’ll see water inside everything that lives. You’ll see rivers in the sky... You’ll even see water shaping human evolution…You’ll see water in the blueprint of civilization… You’ll see water connected to changes and even conflicts across the world…And for me, after all this…I think one thing is becomes clear. We really can’t take water for granted anymore. So, if there are endless ways to combine atoms to make molecules…What’s so special about water? Water is, of course, a molecule but it is in the most… Intense and intimate relationship with life that one can imagine.

Geologist Stephen Mojzsis speaks to the heart of this film…We need to understand this relationship between water and life…Because, to be blunt, our survival depends on it. Stephen is one of the many experts we met on our journey… And his particular expertise takes us back to the very beginning of this story about water and life. Stephen shocked the science world when he discovered where Earth’s water came from.

We long held this idea… A belief really that water was delivered by comets and asteroids and so on… But instead what we found is that water was already here. And we know this from the investigation of the very oldest minerals of all.

Stephen says that water first showed up on the surface about 4.3 billion years ago.

So much of the surface was molten rock that we call this time the Hadean, which means “hell.”

This is very much like what we might imagine the Hadean Earth was like. A bright red sky. That atmosphere is dominantly carbon dioxide…Soon after it had finished its cooling, rocks and minerals released water as steam. It goes into the atmosphere – expands—and cools and as clouds then result in rain.

So began the first water cycle…And it rained so much that two thirds of our planet was submerged under water. This water has special powers. Well water is, is like the superhero of molecules. Water is a really great solvent…We call it ‘the universal solvent’ because it dissolves more substances than any other liquid.

And that meant, our ancient oceans were this primordial soup of chemicals...That is the crucible of life’s origin. We don’t know for sure but scientists think there was a spark... And then... A water molecule is the link between the non-living and the living world. Stephen says the development of life could not have happened at a more crucial moment. Because at this time, Earth’s atmosphere was mostly carbon dioxide, which acted like a blanket hugging the Earth. That heated things up and threatened to vaporize all of our water.

Earth’s fate would have been a super-hothouse with a dense carbon dioxide atmosphere. No water, no life… hellish surface. But then, Stephen told me, early life evolved to rescue Earth from this scorching apocalypse. Because a kind of bacteria photosynthesized the carbon dioxide out of the atmosphere…

And replaced it with…The highly toxic… Substance called oxygen. Now that’s ironic because without oxygen we can’t [BREATHES IN AND OUT]

And it’s this interplay between life and the atmosphere that continues to keep Earth at the perfect temperature. Not too hot, not too cold, just right for liquid water. Life has actually perpetuated the liquid water…on the surface of our planet for geologic time.Stephen has spent his career trying to find evidence of early life-forms and their watery origins. Searching for fossils that might have survived the 3.8 billion years. These rocks here to the… East and north; they’re called the Amitsoq. Which is one of the most exciting places in the world to see the earliest evidence for life on our planet. Almost all of the fossil rocks from such an ancient time have been churned up or weathered away. This is one of the three places on Earth where the original sea beds still survive. Stephen has travelled thousands of miles to see this single rock face. Get the sun angle right…There’s a layer, here. At first, it’s hard to tell if Stephen is impressed, and then… Holy (Sh)it! I think…holy, holy, holy cow… Stephen thinks that he might be looking at the oldest life form ever found… It will take months of testing in a lab before Stephen can confirm that these markings were once living beings.

It’s the kind of thing that many of us have been looking for many, many, many years. This is the ultimate search for a relative at the base of the family tree of all life itself. Ever since all life has been bound to water .... It is such a fundamental bond, no life can exist without it. Even when life moved onto land. And the plants colonized the surface of the Earth. Even in the driest deserts, they still carry a little bit of the ocean with them. All plants are 90 to 95% water in the first place, and it’s part of their structure, it’s part of their metabolism, it’s part of absolutely everything that they are. Vast regions of our world are getting hotter and drier. For humans to adapt it makes sense to study how nature overcomes the absence of water. So, for 25 years plant scientist Jill Farrant has championed a rare group of plants that can dry out and still come back to life.

So, this is a resurrection moss. It rehydrates extremely quickly, it’s going to happen fast, so watch as I pour the water…

Mosses like this were amongst the first life forms to colonize dry land.

The plants that I work with are commonly called resurrection plants because they appear to resurrect from the dead state. They’re not dead at all; they’re just so dry that they look dead. But you just have to add water. Back in her lab in Cape Town, Jill is trying to discover how resurrection plants are able to break the sacred bond with water and still survive. She wants to use this knowledge to help farmers get through droughts.

My dream is to create a crop that tolerates water loss and does not die and produce food security in the face of drought.

Where if there hasn’t been rain and you get a rain, there’s a guaranteed comeback of your crop.

Imagine if a crop could resurrect in 24 hours the way the resurrection bush does.

Okay, Let’s pour some water on…

In its dry state, the bush transformed its insides into a glass-like substance. And now, as it rehydrates, these glassy tissues soften and come back to life.

The strategy is extremely rare, there are only 135 species in the world that can do this.But, in a drought-prone world…This strategy is a game-changer.

Resurrection plants might be rare, but the genetic potential for resurrection is actually common. It’s in every plant that makes a seed.

Every single crop that we have makes a dry seed, it has the genetics to be a resurrection plant, it just doesn’t switch those genes on in the face of a drought. Let’s actually just turn on those genes…

As water sources for crops become more and more erratic, Jill hopes she can develop her resurrection crop in time to save the world’s most vulnerable farmers. In the Northern Cape, Jill took our camera team to film a spectacular event that dramatically shows this ability of life to come alive, even in the direst extremes.

Now what fascinates me is this leaf. Look at this one, eh…Its going to...[LAUGHS] Purple juice. And it’s got this capsule that all the seeds will erupt from

Jill is introducing us to a secret desert bloom location where we might film the mass flowering of the desert.

There’s so much life here. It’s dormant, and it’s waiting. But, you know, you’re gonna have to have faith that the rains are gonna bring it around. Christian Munoz and his son – who is also named Christiaan – are time-lapse experts, and they have already spent decades chasing the elusive desert blooms.

Some people call us plant hunters. We want to show and to capture the change from the desert to the beautiful super blooms.

They use a computer-controlled camera, which means they can combine two shots, filmed at different times: Once with the bloom... And once without.

Trouble is, there is at least a 6 months gap between filming the two images! And they’re not just shooting in South Africa. They are chasing super blooms all over the world. The Munoz’ biggest challenge has been to film the bloom back home in Chile. The Atacama is the driest desert on Earth. There are areas with no record of rain at all. Checking the weather radar the Munoz family has a reason to be hopeful.

Well, believe it or not, it is raining… There’s just a few drops, but it looks like more rain is coming this way.

Sometimes a few drops is all it takes. Finally, After a decade of work, the Munoz’s can show us the transformative power of water in a desert. Before they die these flowers produce millions of seeds.

And with just a few molecules of water sealed inside each seed, these time-capsules of life can survive everything the desert throws at them. We know of seeds that have sat for 30 thousand years and still germinated when they finally got water.

Seeds, you know, seeds are, I call them miracle technology…Imagine if you had seeds of a Ferrari, you know human technology…Ferrari, a nice car, beautiful - the object of desire of many people – and now you can buy a Ferrari that will arrive in an envelope through the mail… And you get this seed you put in a pot with soil, you water it…And a few months later you have a Ferrari there. Imagine that, imagine that and that’s precisely what nature is doing quietly, silently, with a tree. It started with a seed that weighed just a few grams and it’s able…To build it, the whole thing from gas, water and sunshine, right? No, stop and think about this, what technology we have that match that?

I have never met someone who loves trees as much as Antonio Nobre does. He’s not hugging the tree – he’s listening to the water rising up through the trunk…

The leaves are pulling the water column and it cavitates...It makes… tak tak tak …you can hear it on the stem, on the tree trunk.

Antonio, a scientist at INPE – Brazil’s equivalent of NASA, has dedicated his career to tracking the water molecule on its journey through the greatest forest on Earth. Antonio and his colleagues started by tracking the journey of the water rising through the trees. Measuring the molecules as they are drawn 200 feet high into the canopy. Coloring the water with a UV die, scientists can even observe the flow of water through each individual leaf. A rainforest tree can pump 260 gallons of water a day. Heated by the sun, the water escapes as vapor into the sky. But, Antonio noticed that alongside water the trees were also releasing something else. Rising out of the forest they measured tiny particles of dust – so small they would be dwarfed by the spray from a perfume bottle.

Why trees are releasing this dust? You know, this is like Sherlock Holmes, sort of, of mystery, what is going on there?Antonio and his team discovered the forest was conducting transactions in the air. Creating its own cloud system... Because, every cloud and every raindrop is formed on a speck of dust. The technical term is “condensation nuclei” but Antonio gave it a name that I like a lot better.

It’s like you dropping magical dust like fairy dust and then pfff pfff it start raining.

Fairy dust is another seemingly magical expression of the bond between life and water.

It is like seeding the air so that it would benefit itself. So, forest is cranking its own rain.

Antonio’s discovery immediately sparked a new mystery. Everyone assumed that in the dry season Amazon trees stop pumping water…But that’s not what happens.

The Amazon trees do something that is counter intuitive. They transpire more water during the dry season than during the wet season. The trees there are crazy… But they don’t care, they, they just pump, pump and pump. They respond as a group.

And it’s a big group... 400 billion trees pumping a staggering 20 billion tons of water each day, into the sky.

It rises and condenses on fairy dust to make clouds. And then all these clouds move like a river. Only this river – is in the sky!

It captured the imagination, people said ‘Wow there are rivers in the sky? How come?’ Well it’s a concentrated flow of moisture… And they bring moisture from point A to point B, like a river.

Above the forest, the aerial river is even bigger than The Amazon River itself. You could think of this as the largest river on Earth. And it flows far beyond the boundaries of the forest... Blocked by the Andes mountains, it is forced to turn south... Travelling 2000 miles, beyond the city of Sao Paulo. Dumping water as it goes, it transforms areas that should be deserts, into fertile plains. And floods the prairies of the Pantanal, creating, the largest wetland on Earth! Which boasts the highest concentrations of wildlife in South America! So much water arrives that the usual rules for animals seem to be turned upside down.... Fish eat fruit from trees. A tapir, having lost its meadows, grazes while holding its breath. Even jaguars move from land and hunt in the water. The Amazon isn’t the only flying river. From the rainforests of Borneo to the African Congo, there are many forests with the power to shape global weather. Combine this with the natural ebb and flow of the seasons and what you get is Nature’s great pulse.

This is eh, 10 years of data, of what plants are doing. The whole biosphere. Low productivity in red and yellow, and high productivity in green and blue. This is showing you what the biosphere is all about. Life – it’s pulsating, like a heart… heartbeat.

Water is Earth’s bloodstream. And life is the result. And now researchers are following the paths that water and life take together. And, new technology can open up an even greater understanding of how the movement of animals is connected to the pulse of water. When we caught up with Martin Wikelski, he was busy putting a tracking device on a young giraffe. But it’s not just giraffe that he studies - Martin is actually coordinating a world-wide animal tracking revolution. Martin’s high-tech miniature tags can relay live feeds via the international space station to scientists anywhere in the world.

Well done! Well, on animals we have these tiny little tags, that have a solar panel and a battery and electronics inside and an antenna. And that can be as a backpack or it can be a little ear tag.

Martin even makes tags small enough for insects – like this Death’s Head Hawk Moth. With these smaller tags, Martin follows the signal from his airplane, downloading the tracks to his global maps.

It’s really amazing. This is the first time that we tracked, that anybody ever tracked, any of these nocturnal moths… That we really know what they are doing. This is completely new.

Martin is able to gather all this data from creatures great and small… Into the Icarus database — or as some call it, “the internet of wings.” It gives him a live, global overview, where he can actually see how the patterns of animals connect with the pulse of water.

So, water is actually the most important thing. In a lot of cases we see that water is driving migrations, movements or entire life histories of animals.

Wildebeest follow the rains as they sweep across the Serengeti. They know the rain will transform a desert into one of the richest grasslands on Earth. As they graze, these 1.4 million stomachs break down the grass and return the nutrients to the soil in the form of dung and urine. And, discoveries in the Serengeti reveal the greater the animal impact, the more the landscape is enriched and is able to hold even more water.The movement of animals can affect the landscape just as much as the movement of water does. Twelve million snow geese seem to know the exact moment the snow will melt in the far north.

On their migration they disperse nutrients and seeds they have eaten across thousands of miles.

A lot of the movements we see here are related to water. So we have the ice, when it melts, you see the snow geese going up from California. The productivity of populations of animals, like geese in the arctic, is highly dependent upon water. So it’s, it’s really a system that drives almost everything.

Everything from great herds to tiny insects, is perfectly synchronized with the pulse of water. But, for us, one story really stood out…An incredible journey following water on a record-breaking adventure. Wandering glider dragonflies hatch in the rice paddies of India. And as the monsoon rains sweep off the southern coast the tiny insects rise five thousand feet into the air! Following the water far out into the Indian Ocean! The mystery of where the dragonflies go caught the attention of biologist Charles Anderson… when millions of wandering gliders suddenly appeared, in the Maldives, 400 miles off the coast of India. I realized that something quite extraordinary was going on because…Dragonflies absolutely need fresh water to breed… And Maldives is a place with no surface fresh water. So, what on earth are they doing, why are they coming here, what on earth is going on?

Without breeding water, flying all the way from India makes no sense. Unless the dragonflies were on the way to somewhere else…Remember those flying rivers over The Amazon? In a similar way the monsoon brings rain from India to Africa. Charles tracked how the dragonflies were hitching a ride on these storms...

Incredibly, the tiny insects about a week flying 2500 miles across the Indian ocean...All the way to Africa.

Most people cannot believe that a 5cm insect could possibly cross an ocean…And yet they do.

The rains create temporary pools. And the dragonflies arrive to be among the first to colonize them. In the water, their nymphs prey on mosquito larvae. Within just 7 weeks, they’re ready to emerge... and transform into adults. The Wandering Gliders wait for the seasons to change. A circuit of the Indian Ocean takes four generations to complete. A round-trip of 10 thousand miles!

This is the, the largest, uh, most amazing migration, of any insect, in some ways of any animal. To cross oceans, to pass between continents it, it is quite extraordinary.

Their relationship with water is extraordinary. And, in Africa, they eat so many mosquitoes they can end up being the most effective way to control diseases, like malaria.

So imagine… What if farmers in India spray too many pesticides and kill the dragonflies?

It could cause a deadly malaria outbreak in Africa.

We are really just at the beginning of a new phase of understanding Earth’s systems. Because… we finally get glimpse of how life is moving and interacting round the planet and this is super exciting to us.

The pulse of water connects all the plants… All the forests…And all the animals… But, of course, this pulse also connects you and me. Over 7 billion of us depend on the pulse of water. Our success as a species has been to harness the pulse…We use water, above all, to feed ourselves. But we now know that droughts are increasing in intensity... Becoming longer...Breaking records. The pulse of water might not be as reliable as we thought. On our travels across America we met farmers who are experts at growing food in dry climates. But for many of them, the most recent droughts have been overwhelming. There are folks that have run out of water. And if there’s no water here, there’s no value. There’s no value at all. We’re so thankful this morning for the rain that we’ve had!

I know here ever drop counts and we’ve been praying that drought is broken in West Texas… After 2010 we’ve had a…Pretty good decline in rain and I’ve been stuck pretty dry for the most part for about the last 9 years. We try to sustain until we get rain and if there’s no rain then we have to sell. So the water table has dropped significantly in this area. Without water, there’s no livestock, there’s no people.

It’s not only farmers who suffer. Without water, entire communities are collapsing. And it seems like nothing can be done… Other than to pray.

Heavenly father, we thank you for this day, we thank you for the blessing. We please ask that you keep the rainfall coming and let it nourish our pastures and nourish our crops. Amen.

Scientists have developed a unique technology to follow the droughts and to measure the amount of water held in the vegetation below.

This is clear all the way to the end. You wanna continue down? Yeah, I’ve got these. How many miles down? About 10 to go. Uh, yeah. Yeah the [UNCLEAR]. They call Greg Asner ‘the drought chaser’.

We have found ourselves chasing these drought events…And when I say chasing it’s somebody calling me up and saying, “Greg we have this drought, can you come and help us to make that assessment?”

And it used to be that we’d get that call once a year and now I’m getting that call, I’m not kidding, at least once a month if not once a week.

Greg’s technology can see – and measure – water…In ways impossible with the naked eye.

As he flies over, Lidar scanners use a laser to create a high-resolution 3D map of the forest below. At the same time, Greg’s cameras record a spectral image, which means they can see the chemical make-up of each tree… including the movement water in the canopies. In 2010, the drought chasers were called in to analyze a drought in the Amazon...We had this mega drought show up…Across a lot of the Amazon Basin, especially in Brazil. The imaging systems on board our plane were lighting up, literally the big screens were showing enormous amounts of loss. And we saw this everywhere, all over the western Amazon. We saw mortality that easily was over 50% of the tree canopy; and the reason this is alarming…Is that at any given moment in time you would expect to see about 1 to 2% of the canopy in a state of dying, just naturally. When you see 50%, 50 times the rate, you, you don’t have words for it. Scientists like Greg Asner believe if just 25% of the Amazon is lost, it will reach a tipping point that could fatally damage the rivers that fly above the forest. People like Antonio Nobre think we’re already there.

And in 2015 there were worrying signs he might be right. 2000 miles away in Brazil’s biggest city - Sao Paolo - the flying river had stopped its flow and the people were running out of water. Antonio Nobre lives there. The drought…Struck us, you know, head on, and, and I started getting really concerned. The army start preparing for riots because imagine, 22 million people in the largest Brazilian metropolis running out of water, and… People got so like, “what are we going to do? We don’t have water, not even for drinking?” The only explanation is that we are damaging the Amazon. You damage the forest, you damage the flying rivers; therefore… You damage the water cycle, the pulses stop. It’s like a heartbeat that, all of a sudden it stops. While we were filming in here, we found one of the most unexpected effects of the Amazon drought... On the Rio Tiete. Normally, there is enough water to flush pollutants from Sao Paolo out to the sea. But in the drought, the pollution intensifies. Phosphates and industrial chemicals combine to create this toxic foam.

To kayak here you have to wear a biohazard suit. It’s the saddest image of a river I have ever seen.

Multiple organ failure, you have that term in, um intensive care units, multiple organ failure, it’s going on right now on the planet.

And that organ failure has been even more clear as the Amazon forest recently started to burn. That, connection, between drought and fire is a story we know well where I live in California. Our drought started in 2011 and lasted six years. It got so bad the Governor asked Greg Asner to come map its effects on our forests. This is a dramatic landscape where we’re seeing, I would say 30%, are severely drought stricken and maybe 20 are surviving.

Greg estimates that the drought in California killed 140 million trees. Without moisture, the forests are like a tinderbox. The famous Malibu coastline beneath a rising tower of smoke.

2018 was the worst fire season in California’s history, with over 8 and a half thousand fires burning close to two million acres and killing over a hundred people.

Oh my God, I don’t know what to do. Oh my God, I’m surrounded by fire and I don’t know which way to go. Oh please, dear God. Oh, no way. So, you know, the system is changing, the water cycle is uh, changing on us. Yeah, it’s time to go. Those are really big, fundamental planetary scale, changes that are affecting everybody. Amidst all this destruction, Greg Asner remains hopeful. Because, whenever he flies, he finds places that somehow manage to beat the drought. He calls these places ‘refugia’.

Whenever I’ve seen these massive losses, whether it’s in the Amazon basin or in California or in the Pacific islands like Hawaii, we always have refugia emerge…As places of survival. This is an example of a refugia, or a refuge, during the 2016 peak of the drought in California and what you see here are mostly coastal redwood trees. What defines this as a refuge is the fact that there was enough water on the landscape persisting in the soil…To generate a sustained or resilient set of, uh, trees in this forest and that’s why they’re showing up in blue. Protecting refugia protects water supplies of the future.To me those are the, the nuggets, the gold nuggets of nature that give me hope that, not just hope but literally the biological resource, for re-expansion of those species. The key really is finding them and protecting them and allowing them to persist into the future. Our future is bound to water.

Because of the intimate connection between life and the molecule that made us...

On Earth you have a paradise. You have water… In the liquid form, for 4 billion years... What is allowing for water to remain in the liquid state on Earth? It’s life. The take home message here is - life is the key.

The pulse of water, moving across the Earth, is the very thing keeping our planet alive. But that pulse is changing…Because of us. And, you don’t have to be a scientist to realize what’s at stake… Even though our human world is vulnerable to these changes, what fascinates me, is how resilient nature can be. If we give it a chance...I realize now, it’s not the water that I was taking for granted...But where it comes from. It’s nature we need to fight for, as if our lives depend on it. Because they do.