NOVA explores the fiery moonscapes and lush rainforests or the world's most isolated archipelago: the Hawaiian islands. From blistering beginnings as molten rock, the islands have developed into a verdant paradise of unique lifeforms.
Category
📺
TVTranscript
00:01Tonight on NOVA, it is the world's most active volcano.
00:05Its lava destroys everything in its path.
00:09But the ferocious beauty of Mauna Loa plays a dramatic role in the evolution of the isolated islands of Hawaii.
00:16Against the lush backdrop of land and sea, witness the creation of new islands,
00:21and the joy of scientific discovery.
00:24I think we got it this time.
00:26Oh wow! Ha ha! Yeah!
00:28Hawaii, born of fire.
00:39Funding for NOVA is provided by Merck.
00:44Pharmaceutical research, improving health, extending life.
00:49Merck, committed to bringing out the best in medicine.
00:54And by Raytheon.
00:55Through a commitment to technology, Raytheon offers a broad line of general aviation aircraft.
01:03Raytheon. Expect great things.
01:06Major funding for NOVA is provided by the Corporation for Public Broadcasting
01:11and by annual financial support from viewers like you.
01:17The ancient Hawaiians believed that the goddess of volcanoes, Pele, was born of the marriage of earth and sky.
01:32She was a destroyer.
01:41Unforgiving in her wrath, she incinerated everything that stood in her way.
01:45Even scientists who come to Hawaii to study volcanoes invoke her name with respect.
01:54To look at the lava that Pele still sends us is to catch a glimpse of the deep interior of the earth.
02:03A seething inferno hardly changed since the formation of the planet more than four billion years ago.
02:09Billion years ago.
02:10You get this enormous sense of power, this enormous vibration and deafening noise.
02:19And really, they take over your body.
02:27There's a certain romance working with volcanoes.
02:31And it's this opportunity, I think, to combine this level of excitement with trying to solve a geological problem.
02:39In other words, try to figure out how does a volcano work?
02:43What's the nature of the magma that's supplying the volcano?
02:49Mike Rhodes and other scientists come to the world's most active volcano
02:54in search of answers to some of the deepest mysteries about the planet's interior
02:58and the formation of its surface from molten rock.
03:01But they also come because of a story as old as the earth itself.
03:11The creation of new land and the arrival of life.
03:18Here it happens almost overnight.
03:20Drawing scientists to this natural laboratory
03:23to learn about the twin forces of destruction and creation.
03:27Though this is some of the youngest and harshest land on earth,
03:32life can be found in every corner, spreading explosively.
03:43Old land is covered and new land is created
03:46and faster than almost anywhere else on earth.
03:49Lush new forests arise from the ashes of destruction.
03:57This drama of decimation and rebirth began over 70 million years ago
04:07when the first Hawaiian islands broke the surface of the mid-Pacific,
04:11eventually becoming islands of life like the earth itself.
04:16They're more than 2,000 miles from the nearest continent,
04:20the world's most isolated archipelago.
04:23Although there are hundreds of active volcanoes in a narrow belt around the Pacific,
04:28the Hawaiian volcanoes are different.
04:30What drives them is still not known for sure,
04:33but there is a compelling theory.
04:35It holds that there are fixed plumes of superheated rock
04:40rising slowly through the earth's mantle.
04:42Perhaps starting at a depth of more than a thousand miles,
04:48one of them reaches the surface beneath the big island of Hawaii
04:52and creates what's called a hot spot.
04:55But the immense engine that drives it is not well understood.
05:01Its heat may come from the earth's very core,
05:05or the plume may rise from a deep region of radioactivity,
05:08an immense perpetual meltdown.
05:11Made buoyant by intense heat,
05:16this huge upwelling of rock, or magma as it's called,
05:20rises a few centimeters a year.
05:22Nearing the crust, the rock melts and forces its way to the surface,
05:29where it erupts as lava and creates new land.
05:33On the island of Hawaii itself,
05:36we've got four very large volcanoes
05:39that have grown within the last one million years,
05:42from the ocean floor up to heights of about 30,000 feet.
05:48Hawaii's Mauna Loa is the world's largest volcano.
05:53Its huge dome dwarfs its younger but extremely active neighbor,
05:57Kilauea, to the right.
05:59Since 1983, Kilauea has been erupting almost continuously
06:04through a series of cracks or rift zones.
06:08Well, we think we know quite a good deal
06:10about what's happening inside Kilauea Volcano.
06:14Although Kilauea Volcano has a single crater at its summit,
06:21magma often manages to push its way through the flanks of the volcano
06:27along one of these two rift zones
06:30and actually break the surface and lead to an eruption.
06:36Lava erupts explosively in spectacular thousand-foot fountains
06:45when the system is under great pressure from below.
06:48The falling red-hot cinders build up steep cones.
06:55But when the fountains die down, the eruption is by no means over.
07:03Inside this smoking cone is a seething cauldron.
07:15A crust of hardened rock floats on a lava lake.
07:18The lake is fed from below and it overflows through a tunnel at the base of the cone.
07:26As the streams spill down the slopes, the lava melts and erodes the underlying rock,
07:33carving out channels.
07:35The lava splatters up the sides of these channels and a roof begins to form.
07:41Eventually the channels will be entirely covered over,
07:45forming underground tubes that sometimes stretch for miles,
07:49only occasionally coming to the surface.
07:56Where the roof of an underground tube has collapsed,
07:59a skylight exposes the river of lava.
08:06Kilauea's activity is under constant scientific observation.
08:11As part of the effort to understand it, Mike Garcia of the University of Hawaii
08:16collects samples of lava for chemical analysis.
08:19We're out on Kilauea Volcano, looking at some of the youngest real estate on earth.
08:26The purpose of our sampling program, which has gone on now for over eight years,
08:32is to try and understand how magma moves within the volcano.
08:37To collect the lava, the lifeblood of the volcano,
08:41it takes a close encounter with Pele herself.
08:44As you get close, you can really feel the heat from the rising gases in this skylight.
08:52What I want to do is see where I can approach the skylight,
08:58where it's not overhung, and be able to throw a cable in
09:02and try to sample a bit of the lava.
09:05This is probably the first place most of this lava has seen the surface,
09:10so it's really quite hot.
09:12The lava is over 2,000 degrees Fahrenheit.
09:17Standing here is like standing in front of a blast furnace.
09:23Garcia will essentially be fishing for lava.
09:26To collect a sample, he uses a long chain with a square steel pipe on the end.
09:31This pipe will dip briefly into the flow and scoop up some lava.
09:38Without protective clothing, Garcia has to move in quickly.
09:46The flowing lava pulls on the chain like a living thing.
09:50Sampling devices are often lost.
09:53The cable can easily get caught.
09:56Okay, I think we got it this time.
09:59It was hung up on the edge.
10:01And there it is. This chain is really hot.
10:06This lava here that we just sampled is very hot.
10:10And it has cooled very little since it passed from the deep interior of the earth.
10:15Even so, the sample is quickly cooled with water.
10:18And Garcia can handle it in only a few minutes.
10:21On Kilauea Volcano, there are a variety of different kinds of analyses going on.
10:28There's geophysics, there's ground deformation, there's gas chemistry.
10:32And looking at the lava is just another tool to try and understand what's going on inside the volcano.
10:40From here, the lava continues to flow toward the coast.
10:44But about a mile downhill, it becomes blocked and is forced to the surface.
10:51The lava we saw in the skylight was extremely fluid.
10:54As it passes down through the tube system and comes out and surface flows lower down the hill,
10:59the lava has lost more of its heat and temperature.
11:02So it's much more viscous.
11:05We're going to try and sample the edge of a Pahoy Hoy flow here.
11:09You can see from all the orange and the cracks that it's molten just below the surface.
11:19This is molten rock that only a few days earlier may have been a mile underground.
11:28It's like a thick paste and stretches into thin, glassy filaments.
11:39By quenching the lava, we're freezing in what was there before we took the sample.
11:47Otherwise, it changes as it slowly cools.
11:50We want to see what was originally present in lava when in molten state.
11:57After Mike Garcia has collected his samples on Kilauea Volcano,
12:02he sends the samples to me and I determine their chemical composition.
12:09And we're using the chemistry of these lavas to try and find out what's happening inside the volcano.
12:16In other words, what's going on in the volcano's plumbing system.
12:21Although it's 15 miles from the summit, this is like all Kilauea lavas,
12:26with characteristic proportions of aluminum, titanium, silica and other elements.
12:32This chemical fingerprint tells just how complex and extensive the Kilauea system is.
12:38But it tells another story as well.
12:41The earliest workers on the island of Hawaii thought that the two volcanoes of Mauna Loa and Kilauea were interrelated.
12:49In other words, that Kilauea was sort of a smaller satellite sitting on the flanks of the much larger Mauna Loa volcano.
13:02When we look carefully at the composition of the lavas from the two volcanoes,
13:08we see that they are quite distinct.
13:11In other words, each volcano has its own sort of chemical pattern, which we can recognize.
13:17It also appears that they've been distinct for quite a long period of time.
13:23And so, in other words, the magma supplying these two volcanoes has to have had separate pathways.
13:34Mauna Loa was born half a million years ago when lava surged upward.
13:39Then, perhaps only 200,000 years ago, Kilauea appeared.
13:43All Hawaiian volcanoes were built this way.
13:48But except for those on the big island, all are now extinct or dormant.
13:53For a long time, no one knew why.
13:57But then it became clear that the story of the birth and death of these volcanoes was part of a much larger picture.
14:03It was discovered that the floor of the Pacific Ocean on which the islands rest is moving.
14:13It is one of 20 or so slowly drifting pieces of the Earth's crust called tectonic plates.
14:18There's a whole chain of volcanoes which get progressively older as one goes along that chain.
14:26And this is very difficult to understand except in terms of an interacting plate and a hotspot.
14:34In other words, you have a fixed hotspot and that the Pacific plate is moving slowly over that hotspot at roughly about nine centimeters or so a year.
14:47And so, as this plate moves along, then you're gradually producing volcanoes along the plate as it moves.
14:54For 70 million years, the plate has been moving across the hotspot, carrying old islands away while new ones are created.
15:05The old volcanoes die, erode, and eventually submerge.
15:09And they now form an unbroken submarine mountain range 4,000 miles long, anchored at its southern end by the Big Island and its active volcanoes.
15:22This process is far from over.
15:25To the east of the Big Island, a new volcano is rising.
15:29Still 3,000 feet down, Pele's newest creation is called Loihi.
15:34Under the shadow of Mauna Loa and 13 miles off the coast, Loihi is so deep there is no sign of it on the surface.
15:45And the only way to find out what it's doing is to dive to it.
15:51The research vessel Keela from Honolulu is approaching a position over Loihi.
15:57In tow, she has the submersible Pisces 5.
15:59Alexander Malahoff of the University of Hawaii is directing a study of Loihi.
16:10He and his crew approach the platform on which the submersible is mounted.
16:17The pilot, Terry Kirby, followed by Malahoff, climbs aboard Pisces.
16:21They have devised a way of safely launching the sub in the often rough seas.
16:30They enter and check the systems and watertight seals.
16:38When all is ready, air is released from the platform's flotation tanks and it begins to sink.
16:44When they have descended well below the rough water of the surface, the sub will be released.
16:53Keela, this is Pisces 5, we're ready to dive, dive, dive, over.
17:05Roger, Pisces 5, this is Keela, standing by for dive, over.
17:0960 feet down, the water is stable, and the launch of the submersible will be safe.
17:22We're on our way.
17:23We're on our way.
17:30Malahoff and Kirby move off under power, leaving the platform behind.
17:43Steep and jagged, the young island-to-be rises almost three miles from the ocean floor.
17:48This is Malahoff's 35th dive.
17:51Malahoff's volcano's been probably building for 100,000 years or more.
17:57So Louie is our clue to the infancy of the Hawaiian Islands.
18:02That's the beauty of it, because they're able to observe the processes by which these Hawaiian Islands were formed.
18:08In Louie, we see essentially a volcano in its womb, the womb of course being the ocean.
18:21At a depth of 3,500 feet, they make visual contact with the mountain.
18:25They are midway up the face of a wall of dark volcanic rock, exposed when a section of the mountain sheared off in a giant landslide.
18:44Their lights have a range of 30 feet, so they have to stay close to the cliff.
18:48So close, there's a chance of hitting it, maybe starting a dangerous landslide.
18:55Their ascent is slow and careful.
19:00Even so, the sub collides with an unseen overhang.
19:03We have an overhang at 1,010 meters.
19:12The vertical wall, still ascending the slope.
19:14We've stirred up these translucent bacterial mats.
19:18So we can back off.
19:19Time is now 9.19.
19:22They check for damage to the sub.
19:24Then they resume their ascent, until radar shows they've reached the top.
19:29Okay Dave, we're on the bottom.
19:32We're at Pelley's vents.
19:34First discovered in 1951, Louie was thought to be ancient and inactive.
19:39But in the 1970s, earthquakes were detected here.
19:44A sure sign of volcanism.
19:46And there were other clues as well.
19:48It wasn't until 1980, when we first took bottom cameras down on the summit.
19:53And we found the presence of hydrothermal vents that we realized, in fact, that this was an active volcano.
20:04There is a lava chamber inside Louie that heats the summit rocks.
20:10They warm the near-freezing ambient water to 90 degrees, causing a shimmering effect.
20:15The warm water picks up minerals from the volcanic rock and deposits form as chimneys around the exit vents.
20:28The surface of the summit is a virtual desert, except for a yellow-brown bacterial growth that thrives on the chemical nutrients in the warm water.
20:36Only a few solitary bottom feeders and hunters are ever found here.
20:45You really are researching the frontiers of Mother Earth.
20:50And you are, in many cases, the first human being who has seen that particular rock, or that particular landscape, or that particular animal.
20:57Samples of Louie's rock reveal that this volcano has its own chemical signature.
21:07So the hot spot, in fact, is giving rise to several separate plumbing systems, one for Mauna Loa, one for Kilauea, and one for Louie.
21:16Although completely separate from those volcanoes, Louie's interior follows the same basic plan.
21:27Only 150 feet below the summit is a reservoir of red-hot lava.
21:33When magma is pumped into this chamber, Louie inflates as much as 12 inches in three days.
21:40When the pressure is great enough, the volcano can erupt either at its summit or through a rift zone on its flanks, much like Kilauea's.
21:51No one has ever seen Louie erupt, but Malihoff believes it's only a matter of time.
21:57We've never witnessed active volcanism taking place there.
22:01However, we know it's taking place because we've come back and we've seen piles of fresh lava in the same place.
22:06As active as it is, Louie won't reach the surface for several thousand years.
22:13But when it does, it will be a violent birth.
22:17A glimpse of the genesis of Louie and all the Hawaiian islands.
22:22can be seen even today, when lava flows from Kilauea hit the ocean.
22:33But there was more to the creation of Hawaii than volcanic eruption.
22:38When the lava created a platform where there was only water before, it became a magnet for living things.
22:57Marine life was the first to arrive.
23:02It flourished, even though it had to put up with periodic eruption.
23:09The eggs and larvae of fish, coral and crustaceans drifted in on currents from many corners of the vast ocean.
23:15First, one species took up residence, then another, then another.
23:24In a primeval act of creation, lava finally broke the surface of the water and new land formed.
23:31In the beginning, the land was barren and lifeless, in every sense a desert island.
23:44But as the islands grew, almost every climate type on earth developed here.
23:49On nearly 14,000 foot peaks, there were frigid alpine conditions.
23:58Lower down, enveloped in clouds, there were rain-soaked highlands.
24:04Each zone was a clean slate, where some form of life had a chance to make a start.
24:10Even where fresh lava baked in the sun, and the Pacific pounded the rock into black sand.
24:19Birds arrived, some migrating, some blown off course.
24:26Many came from Southeast Asia and the South Pacific,
24:30where most Hawaiian plants and animals have their closest relatives.
24:34Just one bird could carry dozens of seeds and other hitchhikers.
24:39Three quarters of all Hawaiian plant species probably came from seeds brought by birds.
24:46The rest drifted in on the water, or the wind.
24:52Getting here was hard enough.
24:57Survival was even more so.
25:00Seeds might arrive, but without soil, how could they take root?
25:05Without plants at the base of the food chain, what animals could survive?
25:09Even if they did, without mating, they would vanish without a trace.
25:16On the average, only once every 50,000 years,
25:20did a chance arrival establish a permanent population.
25:24Until 1,500 years ago, there were no people.
25:27Perhaps the first plant on some ancient island was lichen.
25:35Covering the rock like a gray carpet, it needs little more than sunlight, moisture and air.
25:41Even today, after an eruption, conditions on lava flows are brutal.
25:46But in only a few years, ferns appear.
25:50As ferns and lichens decay, organic material accumulates, mixes with lava particles,
25:59and one of the Earth's most fertile kinds of soil begins to form.
26:02Then a forest claims the land.
26:10It not only has rich soil, but also a reliable source of water.
26:15On the windward side of the big island, trade winds bring water-laden clouds.
26:22When they meet the great bulk of the mountain, the clouds are cooled and a gentle rain falls.
26:28This is one of the wettest places on Earth.
26:33300 inches may fall every year, high on the sides of the volcano,
26:39nourishing the growth of a rain forest.
26:49What was once windswept rock is now moist and sheltered.
26:53As the forest grows, there are places to hide and things to eat.
27:00New life moves in.
27:08It has taken untold generations for this cast of characters to descend from the few that made it.
27:13In that time, they have changed so much that over 90% are now endemic to Hawaii.
27:22They occur nowhere else in the world.
27:27Well, I think this looks like pretty good habitat, Steve.
27:30For biologists like Rosie Gillespie and Steve Montgomery, this is a living laboratory.
27:34You can see the little silk threads all over the place.
27:37This is a good sign for it, for the tetragnata.
27:41Here it's possible to see, again and again, how living things colonize brand new habitat.
27:48These are wonderful areas. You can see that there's a thread that runs through in there.
27:52These spiders, like everything else native to Hawaii, are descended from a long line of great travelers.
28:00Spiders originally probably got here through ballooning,
28:07which is a funny way that's unique, really, to spiders of dispersing.
28:12They do this just as spiderlings. They get out of the egg sack and then they will go up something like up to the top of a branch or something.
28:23And then they'll put their little abdomens up in the air and let silk out.
28:29And the wind will pull on the silk and it'll pull more and more as they let more and more silk out.
28:34And then they'll finally take off, kind of like Mary Poppins takes off with their umbrella.
28:38And they'll just sail up into the air.
28:46Imagine a little spider just ballooning its way over thousands of miles of ocean.
28:52But just occasionally one of them has made it, or perhaps two of them made it.
29:01But then they had to find suitable habitat and a mate.
29:04The odds are staggering.
29:07Only four out of the 100 major groups of spiders are well represented in Hawaii.
29:13And scientists conclude that all these must have descended from only four successful arrivals over 70 million years.
29:20The isolation was so great a barrier to most animals that among the creatures native to Hawaii, there are no snakes, no frogs, no ants, and except for bats, no land mammals.
29:36Things common throughout the world never made it here on their own.
29:40Because Hawaii is so far from the continent, so very, very few plants and insects and other spiders and whatnot were able to arrive.
29:50So those few successful colonists essentially won the sweepstakes.
29:57They had all these resources of food plants and all these mountain peaks and valleys to populate.
30:03And as they did, they evolved and changed and adapted in all these ways to make use of all these resources.
30:09With all the collecting Montgomery does, he never ceases to be amazed by his discoveries.
30:19Well, these tree ferns are a good spot to find that kind of a caterpillar that likes to hide on ferns.
30:26This is a little tree fern.
30:27This is a little tree fern.
30:28Wow!
30:29It looks right there.
30:30See that notch?
30:31Amazing!
30:32You'll find them hiding in between the leafers.
30:36So they're quite a dominant predator on the foliage in Hawaii, and that one's only about eight million years.
30:43How in the world did you see that?
30:45Well, turning over the fern helps because they bend down a little bit, but it took me about three years to figure out where that species was hiding.
30:53Montgomery was the first to describe these caterpillars and to make the discovery that they were carnivorous.
31:00Found only in the Hawaiian chain, this is an ambush hunter that waits for unsuspecting prey.
31:08It evolved from a plant eater into a predator.
31:11This was such a successful adaptation that there are now at least 18 species throughout the islands.
31:17Being able to catch prey instead of eating plants gave these caterpillars an edge.
31:28What began as a shift in behavior led to a whole new way of life.
31:32But there is more to survival than finding food.
31:40As if the challenge of gaining a foothold here was not enough for plants or animals, they faced repeated volcanic eruption.
31:47To assess how life coexists with a volcano, scientists needed some notion of how often it has erupted over time.
32:01Until recently, they had no idea.
32:03Historical records of Mauna Loa's activity extend back only to the early 1800s, not far enough to understand long-term patterns.
32:22Even the Hawaiian people have not been here long enough to record much of Pele's history.
32:27Dating these eruptions had always been nothing more than guesswork.
32:36Jack Lockwood, a geologist with the Hawaii Volcanoes Observatory, has discovered how to tell the frequency of Mauna Loa's eruptions in the distant past.
32:46It grew out of his work, mapping the lava flows on the surface of the mountain.
32:51At the summit of the volcano is a caldera from which thousands of flows have erupted to build the mountain, but only the newest are visible.
33:03We may see perhaps five to six hundred flows presently at the surface.
33:09Those flows have a spectrum of ages from more than 10,000 years to the youngest flow, 1984 age.
33:16Today, Lockwood has picked out a flow for dating.
33:21He's looking for a place where the contact between that flow and the older one underneath it is very well defined.
33:29There is no way to test the lava itself for age.
33:32Sometimes, remains of the plants in its path were preserved as charcoal under the cooled flow.
33:37If we can find bits of charcoal, it'll be dated by the radiocarbon method, then we'll know when the plant died, and it was of course killed by the lava flow, so that will tell us the age of the lava flow.
33:53He is joined on the expedition by his wife and collaborator, Marty Lockwood.
33:57They search along the contact line between two flows, the most likely place to find the occasional plant remains that escape total incineration.
34:17Total incineration.
34:18Hey, look!
34:19Hey, look!
34:20Look!
34:21Far off!
34:22Look at that!
34:26Okay, hey, that's really neat.
34:28Look at the way that came down through here on top of there.
34:32This is a good place.
34:33We're giving it a shot.
34:37Okay, this one comes off.
34:38Okay, this one is coming off.
34:40Oh, it's dark.
34:41Oh, wow!
34:42Okay.
34:43There's the charcoal.
34:44Let's see.
34:45Isn't it?
34:46I don't know.
34:47Or is it just an old root?
34:48I can't tell.
34:49Part of it's roots.
34:50No, it's modern.
34:51No, it's modern.
34:52It's modern.
34:53It's modern root.
34:54The problem is that you've got to define actual carbonaceous charcoal that was cooked by the lava flow.
35:03There's lots of organic material.
35:04There's lots of plants that send their roots into the same zone, and those roots die, and they look like charcoal, but they're not the real thing.
35:14Even though Lockwood has found over 300 samples in 12 years, this is like looking for a needle in a haystack, and the trip could easily end in failure.
35:27Oh, it's loose.
35:28Great.
35:30Okay.
35:31Oh, look at the glass.
35:35Look at the glass in this part.
35:37It's really black.
35:38That's a good sign.
35:41Oh, boy.
35:42Oh, oh, oh, oh, oh, oh, oh, oh, oh.
35:43Oh, oh, oh.
35:44Look, look, look, look, look, look, look.
35:45See the black?
35:46Oh, there's plant impressions.
35:48Hey, okay, guys.
35:49Far off.
35:50Okay.
35:51Oh, beautiful.
35:52You can see where the root went down through here?
35:54Okay.
35:55This, we've now, you know, we found the essential thing.
35:57This is a place where a plant was growing 2,000 or 3,000 years ago.
36:02So, now we're getting excited.
36:03Now we can see if it was carbonized.
36:09Oh, boy, oh, boy.
36:11Oh, wow!
36:11Ha, ha!
36:12Yes!
36:14Okay, far out.
36:15Here's a root.
36:16See the impression?
36:18You can see the impression of the plant.
36:19That was a plant that was actually crushed.
36:21And right in the interstices of where that plant mold is, you can see the carbonation material.
36:27Anyway, more of Paley's history is being revealed.
36:31You know, at times like this, you feel kind of funny.
36:34Or funny, that's not the word, but I feel like I've been given a gift.
36:37Like, Paley is sharing a secret.
36:39She's saying, okay, I'm going to help you find out what I was doing.
36:42I'm going to help you tell my story.
36:44Well, hey, look at this one.
36:46Oh, far.
36:47Wow.
36:48Oh, wow, wow.
36:49Let me have those others, too.
36:50Oh, hey, neat, neat, neat.
36:52These are great.
36:53These are beautiful rootless.
36:54Look at that.
36:55This thing probably weighs the ground.
36:56This is going to get submitted to a lab in Washington, D.C. at the USGS.
36:59And we're going to find out how old this flow is.
37:02I thought I was going to get skunked out there.
37:05At Lockwood's lab, the charcoal samples are cleaned and weighed for analysis at the US Geological Survey.
37:11Now, this is what we call bomb-proof.
37:12This is a really good one.
37:13In two months, the completed tests will show that these samples and the flow that buried
37:19them are 2,050 years old.
37:24Lockwood is adding the new flow to his map of Mauna Loa by using aerial photographs.
37:29Out in the field, you're trying to determine where the different contacts are between lava flows.
37:36Each one of those lava flows is like a clock that's been frozen in time.
37:40On one side of the contact, you'll have a flow which may be perhaps 1,000 years old.
37:48On the other side of the flow, which perhaps is 2,000 years old.
37:54Lockwood's dates for hundreds of flows show that in the last 10,000 years,
38:00the slopes of Mauna Loa have been almost completely resurfaced by its eruptions.
38:05But the forest always comes back.
38:10Where the activity is greatest, vast areas have been buried many times.
38:17The primary impact of our dating efforts out here has been to shorten dramatically the amount
38:23of time available for all sorts of processes.
38:25Whether it's soil alteration or forest growth or insect evolution or whatever,
38:30it has to happen much faster than people had ever realized before.
38:35It was a revelation for biologists.
38:38On the big island, some mature rainforests, once thought to be thousands of years old,
38:43were now known to be only a couple of hundred years old.
38:49Volcanic eruptions were forcing rapid cycles of death and rebirth.
38:53It's only now becoming clear how this volcanic activity creates new opportunities for life.
39:01When lava slashes through the forest, it kills nearly everything in its path.
39:07What isn't incinerated is buried in ash.
39:14These were once trees, but were encased in flying lava.
39:21Everything in the path of an eruption would seem doomed.
39:24But somewhere, something always lives.
39:30This kapuka, as the Hawaiians call it, is an island of survival where life not only endures,
39:36but evolves with extraordinary speed.
39:38Biologist Ken Kaneshiro of the University of Hawai'i has been trying to understand this process.
39:48He and his assistant, Bill Pereira, are crossing an old lava flow on the way to a large kapuka
39:53that was created after an eruption of Mauna Loa in 1855.
39:57This kapuka is a remnant of an ancient rain forest.
40:14Though birds migrate in and out, small creatures like insects rarely leave its safety.
40:20For the past three decades, Kaneshiro and a team of researchers
40:28have been investigating the way isolation affects the evolution of one family of insects.
40:36This ordinary-looking Drosophila fly is part of a remarkable story.
40:41Hawaii has one quarter of the world's Drosophila species, in fact, more than 800.
40:46And yet, all 800 species may have descended from a single ancestral pair
40:52that arrived 20 million years ago.
41:00It looks pretty good in here, Bill, but let's get further up.
41:04Kaneshiro's group has been tracing the family tree of the flies in this kapuka over many generations.
41:13That looks pretty good around here. Let's do it.
41:15Using bait to attract flies, they compare those caught here with flies of the same species
41:20and another kapuka, only a quarter of a mile away.
41:25Smelling pretty good.
41:28It's almost nauseating. We'll get a lot of flies.
41:31They color the baits with red dye to make them easy to find again.
41:34This looks like a good spot, Bill. Let me have one of those tacks.
41:43The two kapuka's Kaneshiro studies here were created 140 years ago.
41:49Since then, the two fly populations have been breeding in isolation from each other.
41:54Kaneshiro and others have begun to detect subtle differences between the flies
41:58in this kapuka and those in the adjacent one.
42:02We've been doing some studies comparing the genetics of the population in this kapuka
42:07compared to the population in the adjacent kapuka.
42:11And within the very short period of 140 years or so,
42:16there's been very significant gene frequency differences
42:19occurred between these two populations.
42:21These differences suggest that the flies have taken the first step
42:28in the evolution of a new species.
42:30Kaneshiro is certain he has found out how this process occurs so rapidly.
42:38These kapukas create situations where drosoppa, for example,
42:43are subjected to small population sizes.
42:46And it's this small population that is most important for understanding
42:50the speciation process.
42:55It was known that a sudden reduction in numbers for any animal
42:58could lead to inbreeding or even extinction.
43:04But what Kaneshiro's group found came as a surprise to many
43:08and remains controversial.
43:12Our idea is that changes within the sexual environment,
43:17within the mating behavior of these flies,
43:20are more important in the speciation process than most of us ever believed before.
43:27Here's how it works.
43:29Most Hawaiian drosophila flies have elaborate mating rituals.
43:36These rituals often begin when rival males, like these two,
43:40fight to establish dominance.
43:42The victors of contests like this will form a small class of super males,
43:49which dominate the courtship arena.
43:51The other male will join a large group of losers that don't stand a chance with the female flies.
44:01During courtship, this male raises his abdomen over his head and tempts the female with scent secreted from its tip.
44:12Like many female flies, she's choosy and shows interest only in super males, the most accomplished suitors.
44:24But in a new, isolated Kapuka, the population is so small that there may be hardly any super males.
44:38This means the choosy females may never mate.
44:46This male tries to mount a female, but he doesn't meet her high standards and she shakes him off unceremoniously.
44:54However, some females relax their standards and will now mate with virtually any male that comes along,
45:04including the losers that normally never mate.
45:07These males introduce new traits into the gene pool by mating often with indiscriminate females.
45:14These actively breeding flies are nature's hedge against extinction when the population is severely reduced.
45:23This female's offspring will be better adapted and increasingly numerous.
45:38A kind of genetic revolution is underway and it may be the first step in forming a new species.
45:48What we have here is a situation where you have volcanic activity creating Kipukas, which results in small population sizes in these flies,
46:01which then causes a shift in the mating system, which then results in a shift in the genetic system,
46:08the genetic background of the population, which then leads the population in a different evolutionary pathway.
46:14Every time lava plows through forest, dividing it up, separating once continuous populations of plants and animals,
46:31there is a potential for change.
46:33But while the volcano is rearranging the existing landscape, it's also creating an entirely new and hidden world.
46:50When this lava drains away after the eruption stops, what's left is a network of caves.
46:56After the rock cools, the forest returns to the surface and around the mouth of the cave.
47:03Frank Haworth of the Bishop Museum and Fred Stone, a colleague from the Hawaii Community College,
47:13have been exploring these caves for 20 years.
47:15The rock of Mauna Loa is honeycombed with caverns like this one.
47:24This cave is only 110 years old, being in the 1881 lava flow.
47:30As soon as the lava cooled and vegetation started to grow, they send these roots deep into the lava,
47:37getting moisture and nutrients from the rock.
47:42The ceilings are festooned with these roots, making a curtain of living stalactites.
47:49The tunnel snakes for miles up the mountain.
47:52As they go deeper in the cave, the air becomes stagnant, humidity is a hundred percent,
47:58and the temperature is a constant 70 degrees.
48:02The darkness is total.
48:04The only sound is the steady drip of water.
48:10This low, low passage going down and then back up, it opens up, up ahead.
48:17The caves are lightless, isolated, and doomed to certain burial by newer lava.
48:27Most biologists assume that except for the entrances, they would be hostile to life forever.
48:34It's so important in biology if you assume there's nothing there,
48:37and then it's a self-fulfilling prophecy that nobody finds it.
48:41But in 1980, Frank Haworth discovered a system of totally cave-adapted life here
48:47that defied conventional scientific wisdom.
48:51Oh, there's a caterpillar.
48:53Oh, yeah.
48:55I wasn't really looking for cave life, so that when I saw an animal in the cave,
48:59I knew that it was of some biological interest.
49:04I had assumed these were accidental animals or visitors to the cave like myself.
49:11For a while, every trip was yielding new species.
49:15That was when I realized that there was nothing anywhere else in the world
49:19that even came close to this, that we must be on to something.
49:23It wasn't long before the pieces started coming together of this being a complete ecosystem,
49:31fed by tree roots and organic material that percolates in from the outside through rainwater.
49:39Oh, look, I think there's a cricket over here.
49:42As soon as roots appear, creatures like crickets are soon to follow.
49:46Opportunists and scavengers, they can eat almost anything, from vegetation to other insects.
49:57Although descended from crickets of the forest, these have been transformed as they evolved in the caves.
50:07Headlong leaps in the dark are dangerous, so once powerful jumping legs have become long and spindly.
50:13This species only jumps when you threaten it with imminent squashing.
50:19Otherwise it will just run away, most uncricket-like.
50:24For most cave creatures, without daily or seasonal cycles, time loses its meaning.
50:32Without light, eyes often become useless and blind.
50:37There is a sensory shift.
50:39Many have acute senses of smell and hearing.
50:44Others feel their way around with elongated antennae.
50:49Completely cave adapted, these crickets could never survive a trip above ground.
50:55They had to come in from another cave.
50:57When the lava cooled, it shrank, forming a network of cracks.
51:07In their never-ending search for new places to live, crickets and other creatures used these cracks to migrate from old caves.
51:18Like a new volcanic island, the cave was a harsh frontier.
51:29But there was little competition, plenty to eat, and safety from predators.
51:33Like a kapuka, this was another island of opportunity for colonists.
51:47The new species aspect was exciting, but to put it together and figure out how the ecosystem worked was tremendous.
51:55There were creatures here that had all survived the same harsh test, adapt or perish.
52:06And when Haworth found them, he found a whole system of life thriving in an island of permanent night.
52:12One of the most profound lessons of the Hawaiian Islands is that few places on earth are too bleak for plants or animals to gain a foothold.
52:27Life here has turned barriers into stepping stones.
52:31For new arrivals, profound isolation meant freedom from competition and safety from most predators.
52:45What once was naked rock has in only a tick of the clock of geological time become lush with living things,
52:53all descended from a handful of hardy pioneers.
52:56What began as a desert island became a giant mountain.
53:07Lava will one day cover everything on the slopes of Mauna Loa and Kilauea.
53:13But for every act of destruction, there will be an act of creation and a new stage for Hawaii's evolutionary drama.
53:20And presiding over it all will be Pele, the goddess of fire.
53:34Pele came from the west, visited all the islands in turn,
53:40and when she saw the big island and its vibrant life, she made it her home.
53:50But Pele is a restless goddess, and one day she will move on and raise up other great mountains, for she is the maker of the land.
54:03The mother of the land.
54:11Educators, educational institutions, and organizations can purchase this and many other NOVA programs for $19.95 plus shipping and handling.
54:25To order, call 1-800-255-9424.
54:29THE END
54:59THE END
55:28NOVA is a production of WGBH Boston. Funding for NOVA is provided by Merck. Pharmaceutical research, improving health, extending life. Merck, committed to bringing out the best in medicine.
55:45And by Raytheon. Through a commitment to technology, Raytheon offers a broad line of general aviation aircraft. Raytheon. Expect great things.
55:58Major funding for NOVA is provided by the Corporation for Public Broadcasting and by annual financial support from viewers like you.
56:07This is PBS.
56:15Next time on NOVA, is the sky falling?
56:18We heard this tremendous crash and saw this huge hole.
56:22Comets really do impact planets. A big one could come in at any time.
56:27The Doomsday Asteroid. Next time on NOVA.
56:34For more information about NOVA, visit the PBS homepage on the World Wide Web at www.pbs.org.