[00:27.87]Away from all land
[00:34.22]It covers more than half the surface of our planet
[00:37.69]and yet for the most part it is beyond our reach.
[00:45.74]Much of it is virtually empty
[00:49.86]a watery desert.
[00:57.31]All life that is here is locked in a constant search to find food
[01:04.88]a struggle to conserve precious energy
[01:08.32]in the open ocean.
[01:29.81]The biggest of all fish
[01:33.08]thirty tons in weight, twelve meters long
[01:37.60]a whale shark.
[01:40.89]It's huge bulk is sustained by mere microscopic creatures of the sea
[01:51.11]Whale sharks cruise on regular habitual routes
[01:55.28]between the best feeding grounds.
[02:02.14]In February, that takes them to the surface waters
[02:05.89]far from the coast of Venezuela.
[02:11.82]Others are already here.
[02:14.83]Baitfish have come for the same reason to feed on the plankton.
[02:20.23]The whale shark has timed it's arrival exactly right.
[02:26.30]Oddly, the tiny fish swarm around it.
[02:37.95]They're using it as a shield.
[02:44.12]Other predatory fish are lurking nearby.
[02:50.69]Yellowfin tuna. They seem wary of the giant.
[03:02.02]The shark dives, as if to escape from such overcrowding.
[03:11.46]Now the tuna have a chance to attack the unprotected baitfish
[03:29.30]back comes the giant.
[03:38.24]It has taken a vast mouthful of the baitfish itself.
[03:42.28]Plankton, it seems, is not the only food for a whale shark.
[03:57.89]Both shark and tuna feast together
[04:16.56]but the tuna must be wary.
[04:22.89]Even they can end up in the whale shark's stomach.
[04:35.03]Predators here must grab what they can, when they can
[04:39.47]for such events do not last long.
[04:45.15]The dense shoals, on which so many depend
[04:48.07]gather only when water conditions are perfect.
[05:05.13]Many predators spend much of their time cruising the open ocean
[05:16.57]Plankton feeding rays do so, gliding with minimum effort.
[05:35.98]The oceanic whitetip shark
[05:41.15]another energy efficient traveler.
[05:46.41]It specializes in locating prey in the emptiest areas of the open ocean
[05:51.99]patrolling the top one hundred meters of water.
[06:03.72]Taste in water, is the equivalent of smell in the air.
[06:08.64]An oceanic whitetip is able to detect even the faintest trace.
[06:17.31]Small pilot fish swim with it.
[06:19.82]The shark can find prey far more easily than they can
[06:23.26]and they'll be able to collect the scraps from it's meals.
[06:31.58]It's long, fixed pectoral fins
[06:34.93]enable it to soar through the water, with the least expenditure of energy.
[06:45.20]This shark has found a school of rainbow runners.
[06:49.91]It would eat one, given the chance
[06:52.74]but rainbow runners are swift and agile and not easily caught
[07:00.10]so, it bides it's time.
[07:02.76]There's a chance that, eventually, it may spot a weakened fish that's catchable.
[07:26.19]Excitement far from land.
[07:37.72]A school of dolphin five hundred strong.
[07:56.51]They've sensed there's food around, and they're racing to catch up with it.
[08:09.25]The news has spread. Now a number of schools are on their way.
[08:27.49]They're heading towards the Azores
[08:29.92]volcanic islands a thousand miles west of Portugal.
[08:44.54]The dolphin scan the water ahead with their sonar.
[08:47.78]They're close to their target.
[08:58.24]This is it.
[09:04.77]It's difficult for a single dolphin to catch the fish.
[09:09.82]To avoid wasting energy the work as a group.
[09:20.60]They drive the fish upwards, trapping them against the surface
[09:27.09]and there, other predators await them.
[09:36.40]They're waiting for the dolphin to drive the prey closer to the surface.
[09:50.89]Now the shearwaters can dive down on them, descending to twenty meters or more
[10:00.94]and the dolphins block the baitball's retreat.
[10:34.72]The dolphins leave as soon as they've had their fill
[10:43.04]and, at last, the mackerel sink below the diving range of the birds.
[11:11.78]As the Sun disappears, a profound change takes place in the ocean.
[11:18.61]Deep water plankton start to rise from the depths
[11:22.19]and another hungry army prepares to receive it.
[11:50.44]Every night, wherever conditions are right,
[11:53.70]countless millions of creatures from the deep migrate to the surface, seeking food.
[12:08.91]A baby sailfish, fifteen centimeters long
[12:12.95]snaps up everything in it's path.
[12:15.89]In three years' time, it'll be one of the oceans most formidable hunters
[12:20.68]weighing sixty kilos.
[12:23.90]Just now, however, it's very vulnerable.
[13:08.36]These manta rays are giants.
[13:12.25]Eight meters across and weighing over two tons.
[13:19.64]The blade-like projections on either side of the head help to steer plankton into the manta's mouth.
[13:45.71]Dawn returns, and the plankton sinks back into the depths.
[13:52.66]If we are to follow, we must use a submarine.
[14:00.07]As we descend into the darkness, the pressure builds, the temperature falls.
[14:10.06]Below five hundred meters, new, mysterious animals appear.
[14:20.28]Their bizarre shapes help them to remain suspended in the dark space.
[14:29.54]Some resemble creatures familiar from shallower waters
[14:42.07]others defy classification.
[14:50.76]All around, organic particles drift downwards.
[14:57.21]Marine snow, detritus from the creatures swarming in the sunlit waters above.
[15:05.77]The snow is food for many animals here, like the sea spider
[15:11.02]a small relative of shrimps and crabs.
[15:25.72]Those strange leg-like appendages are feathered, to stop it from sinking.
[15:34.05]They can also enmesh marine snow
[15:37.37]which it wipes carefully into it's jaws.
[15:56.40]A sawtooth eel hangs upright and motionless.
[16:04.31]Gazing ever upwards, it watches for prey, silhouetted against the faint
[16:09.01]glimmerings of light from the surface.
[16:18.23]Days may pass before prey swims close enough for it to strike.
[16:28.89]Farther down still, the blackness is complete.
[16:33.59]No vestige of sunlight can penetrate as far as this.
[16:41.79]Food is very scarce and nothing can afford to waste any energy.
[16:50.66]A dumbo octopus simply flaps a fin
[16:54.79]no need for the jet propulsion used by it's shallow water relatives above.
[17:29.99]The weirdest, in this world of the strange, vampyroteuthis
[17:35.87]the vampire squid from hell.
[17:43.71]Disturb it and it only retreats a little distance.
[17:51.57]Go after it, and it has a special defense.
[17:59.46]To see what it does, you must switch off the lights.
[18:05.93]The vampire squid has lights of it's own.
[18:12.07]Bioluminescent bacteria shine from pockets on it's arms to confuse it's predators.
[18:19.80]Are those eyes?
[18:25.87]In fact they're spots at the end of it's mantle.
[18:28.55]A bite there, would leave the head unscathed.
[18:34.24]The threat diminishes, and vampyroteuthis disappears into the blackness.
[18:56.62]At last, the sea floor.
[18:59.20]Over two miles down, the pressure here is three hundred times that at the surface.
[19:06.98]It takes several months for marine snow to drift down as far as this.
[19:16.94]As you travel away from the rocky margins of the continents
[19:21.07]an immense plain stretches ahead.
[19:27.09]It extends for thousands of miles
[19:30.36]gradually sinking downwards.
[19:39.41]There are faint trails in the ooze, signs that even here there is life.
[19:53.20]These are what made some of them
[19:56.36]sea urchins sifting the accumulating drifts.
[20:05.09]Shrimps standing on elegant tiptoe
[20:08.28]fastidiously select the particles that appeal to them
[20:19.76]but, in the deep sea, as everywhere else if there are grazers, there are hunters.
[20:35.95]A monkfish, almost indistinguishable from the sand on which it lies.
[20:46.55]Why waste energy chasing around, if you can attract prey towards you with a lure?
[21:10.93]Maybe that one was a bit big.
[21:16.55]The monkfish can wait, for days if necessary, until the right sized meal turns up.
[21:26.77]Scavengers on the other hand, have to move around to find their food.
[21:34.50]Crabs can detect the faintest of tastes in the water
[21:37.82]and that helps them locate the latest body to drift down from above.
[21:44.38]Eels are already feeding on the corpse.
[21:54.36]Isopods, like giant marine woodlice a third of a meter long
[21:59.00]are ripping into the rotting flesh.
[22:02.86]Over the next few hours there'll be frenzied competition
[22:06.21]between scavengers of all kinds to grab a share.
[22:39.05]Just occasionally, there is a gigantic bonanza.
[22:52.52]The remains of a sperm whale.
[22:55.96]It died five months or so ago.
[22:59.12]There's little left but fatty blubber clinging to it's bones.
[23:06.47]It's flesh has nourished life for miles around
[23:10.15]but now the feast is almost over.
[23:17.87]Spider crabs, a meter across, still pick at the last putrid remains.
[23:31.37]A few weeks more, and nothing will be left, but bare bones.
[23:37.27]The crabs will have to fast, until the next carcass drifts down.
[23:48.93]But not all food comes from the sunlit world above.
[23:54.45]The floor of the Atlantic Ocean is split in two by an immense volcanic mountain chain
[24:01.13]that winds unbroken for forty five thousand miles around the globe.
[24:10.14]In places, it's riven by great fissures, from which superheated water
[24:15.86]loaded with dissolved minerals blasts into the icy depths.
[24:31.61]Clouds of sulfides solidify into towering chimneys, as tall as a three story house.
[24:43.13]At four hundred degrees this scalding cocktail of chemicals
[24:47.29]would be lethally toxic to most forms of life
[24:53.05]but astoundingly, a particular kind of bacteria thrives here
[24:58.39]and feeding on the bacteria, vast numbers of shrimps.
[25:12.99]So, beyond the farthest reach of the Sun's power
[25:16.61]a rich independent community exists, that draws all it's energy
[25:21.20]directly from the Earth's molten core.
[25:39.44]On the other side of the planet, in the western Pacific bordering Japan
[25:45.54]the dragon chimneys, another series of hot vents, erupting in the darkness.
[25:59.06]Here, more, but different bacteria thrive in a similar way.
[26:10.03]And here, too, more crustaceans, but quite different species
[26:14.44]from those around the hot vents in the Atlantic.
[26:23.64]These are squat lobsters, clad in furry armor
[26:28.28]jostling with one another beside the jets of superheated water
[26:32.49]for the best places, from which to graze on bacteria.
[26:42.58]These vents, too, like those in the Atlantic are isolated oases
[26:48.03]so widely separated, that each community is unique.
[27:03.12]Cross to the other side of the Pacific, to the deep near the Galapagos Islands
[27:08.70]and there are yet other fissures venting superheated water.
[27:18.72]One and a half miles down, at a site known as Nine North
[27:23.71]towering chimneys support a spectacular display of giant tubeworms.
[27:35.44]These vents give off so much energy
[27:38.08]that some of the worms reach three meters in length.
[27:42.32]They're the fastest growing marine invertebrates known.
[27:50.96]All told, over fifty different species have so far been found living here.
[28:01.21]The inhabitants of these bustling communities may grow at speed
[28:06.32]but their existence can also be short, for the vents do not erupt indefinitely.
[28:12.90]Suddenly, unpredictably, they may become inactive.
[28:21.83]Nine months have passed at Nine North.
[28:25.57]What were only recently chimneys teeming with life
[28:29.10]have turned into cold, sterile mineral monuments.
[28:37.34]Some eddy, deep in the Earth's crust
[28:40.81]diverted the volcanic energy elsewhere
[28:43.95]and, an entire microworld was extinguished.
[28:56.38]In places, volcanoes have erupted to build great submarine mountains.
[29:02.59]There are thought to be around thirty thousand such volcanoes
[29:07.18]some, measured from the sea floor, are taller than Everest.
[29:17.94]Sheer cliffs soaring to drowned volcanic peaks.
[29:34.43]Powerful currents sweep up the mountains' flanks
[29:37.78]transporting nutrients from deep water towards the summits.
[29:45.29]The hard rock provides excellent anchorage
[29:48.14]for communities of great variety and stunning color.
[29:54.61]Soft corals, several meters across collect the marine snow as it drifts past.
[30:04.35]Whip corals stretch out into the current.
[30:10.44]Giant sponges filter nourishment from the cold water.
[30:29.49]A richly varied community flourishes here
[30:32.81]sustained by the nutrients and detritus in the icy currents that flow around the peak.
[30:44.24]Yet it is all blossoming on an extinct volcano
[30:48.46]a mile below the reach of the Sun.
[31:16.26]A nautilus. It spends it's days hiding four hundred meters down
[31:21.23]But as night falls, it ascends up to the reefs, to look for food.
[31:31.69]It's graceful shell contains gas filled floatation chambers, that control it's depth.
[31:40.98]It's powered by a jet of water, squirting from a siphon
[31:47.69]but it travels shell first, so it can't see exactly where it's going.
[31:58.29]It's nearest living relatives are squid and octopus
[32:01.90]which, over evolutionary time, have both lost their shells
[32:06.76]and the octopus has become one of the nautilus' major predators.
[32:11.84]It's a master of disguise.
[32:20.67]The nautilus keeps well clear of them.
[32:26.13]It's small tentacles carry highly developed chemical sensors
[32:30.67]which can detect traces of both predators and prey.
[32:40.55]It uses it's water jet to dig in the sand.
[32:49.78]Because it devotes so little energy to swimming, it only needs a meal once a month.
[33:00.68]Got something. And just as well. Dawn is approaching and it has to puff it's way
[33:07.20]back, to deeper waters.
[33:31.05]Thirty miles away, shoals of squid are jetting upwards towards the surface.
[33:38.26]By night, they seek small fish among the plankton, but they're cautious.
[33:50.77]Pacific spotted dolphin.
[33:57.11]They're guided by their sonar.
[34:04.32]The dolphin, as so often, are working as a team, synchronizing their attacks
[34:09.86]to confuse their prey.
[34:30.16]As dawn approaches, squid and fish and plankton retreat downwards, to shelter in the darkness.
[35:03.71]Some of these isolated volcanoes
[35:06.39]rise as much as nine thousand meters from the sea floor, reaching close to the surface.
[35:16.34]Around these peaks invigorated by daily sunshine
[35:20.11]marine life flourishes in spectacular abundance.
[35:33.68]Fish crowd here, because the volcano forces nutrients to the surface
[35:39.19]encouraging the plankton to bloom.
[36:00.71]An oceanic wanderer, a mola mola
[36:03.68]stops by to be cleaned by reef fish, at the sea mount edge.
[36:16.46]Butterfly-fish pluck string-like parasites from it's flanks.
[36:28.27]The huge fish lives on jellyfish over a thousand meters down
[36:32.83]where the water is twenty degrees colder
[36:36.77]so, a brushup near the surface, allows it to warm up
[36:41.20]before making more deep water forays.
[36:52.17]The summit of this volcanic mountain rises above the surface of the sea.
[36:58.70]It's Ascension Island
[37:01.60]eight hundred miles from any other land, a welcome vital haven for long distance travelers.
[37:14.09]Frigatebirds spend months continuously airborne at sea
[37:18.66]but at nesting time, they come to Ascension from all over the ocean.
[37:28.32]The island's barren slopes of volcanic ash and lava
[37:32.22]might seem to offer perfectly good sites for a nest
[37:37.93]but the frigates choose an even more isolated site
[37:43.94]Boatswain Bird Island, a lonely pillar, just of Ascension's coast.
[37:57.76]Frigates are the world's lightest bird, relative to their wingspan
[38:02.48]and they can soar for weeks on end with minimal effort.
[38:10.94]They seem much more at home in the skies, than in a crowded colony on land
[38:16.19]but nest, they must.
[38:20.51]They come from all over the Atlantic to this, their only colony.
[38:28.72]There are boobys here, too.
[38:35.78]To raise their young, seabirds worldwide seek such remote islands.
[38:52.44]Swimmers also come to Ascension to breed.
[38:57.52]A female green turtle approaches the coast.
[39:04.22]She's not eaten once, in two months.
[39:09.02]She may have traveled one thousand miles from her feeding grounds
[39:13.21]the greatest journey of her kind.
[39:23.27]Many others are here, too, resting on the sandy sea floor
[39:27.21]awaiting the darkness of night, when it'll be safer to visit the beaches.
[39:38.44]Eggs that were laid a few weeks ago, at the start of the season
[39:42.48]are beginning to hatch.
[39:56.87]Most hatchings happen at night.
[40:00.16]Now, in the light of day, the young are extremely vulnerable.
[40:10.68]They must get to the sea as soon as possible
[40:16.16]but their trials have only just begun.
[40:32.15]Many will drown in the pounding waves.
[41:00.32]During the next twenty years, the vast majority will inevitably die
[41:05.93]but those that survive will, eventually, as their mothers did before them,
[41:10.44]return to the very same beach where they were hatched.
[41:16.57]How they find their way back
[41:18.47]across thousands of miles of open ocean, we still have no idea.
[41:32.02]A frigate soars.
[41:35.70]Somewhere, beneath the surface below,
[41:38.68]there is the food it must have.
[41:45.39]Those that fly above the ocean
[41:47.59]must be able to read the signs of fresh supplies, or perish.
[41:55.66]A hundred miles from the Mexican coast, and keen eyes have spotted movement.
[42:05.99]Sailfish, three meters long, are closing in on prey.
[42:17.07]They will only use just enough energy to make their kill
[42:22.07]never wasting a fin stroke.
[42:29.01]Nearly a hundred sailfish have surrounded a single school of baitfish.
[42:33.60]It's very rare to see so many of these hunters in one place.
[42:40.91]To herd their prey, the predators raise their huge dorsal fins.
[43:03.53]A mistimed strike by one sailfish, could fatally damage another
[43:08.00]but each continually changes it's color, from blue, to striped, to black
[43:13.50]that warns it's companions of it's intentions and also confuses the prey.
[43:21.91]As the shoal is driven nearer the surface, it comes within the range of the seabirds.
[43:42.01]Out here, in the open ocean, there is nowhere for the baitfish to hide.
[44:29.63]Sailfish live a high octane life.
[44:33.74]To survive, they must find prey daily
[44:37.68]so their entire existence will be spent on the move.
[44:53.14]Over ninety percent on the living space for life on our planet, is in the oceans
[45:00.84]Home to the biggest animal that exists
[45:04.63]or has ever existed.
[45:08.53]the blue whale.
[45:18.26]Some weigh nearly two hundred tons
[45:21.88]twice the size of the largest dinosaur.
[45:30.07]Despite their great size, we still have little idea of where they travel in the vast oceans
[45:37.02]and none at all of where they go to breed.
[46:09.67]The largest animal on Earth feeds almost exclusively
[46:14.25]on one of the smallest krill, shrimp-like crustaceans.
[46:21.40]They take many tons of water into their ballooning throats in a single gulp
[46:27.19]and sieve out what it contains.
[46:36.78]Every day, each one swallows some four million krill.
[46:45.60]Such gargantuan harvests depend on the continuing fertility of the oceans
[46:54.77]But global changes now threaten the great blooms of plankton
[46:59.34]on which the whales depend.
[47:04.00]Once and not so long ago
[47:07.25]three hundred thousand blue whales roamed the oceans
[47:11.93]now, less than three percent of that number remains.
[47:20.65]Our planet is still full of wonders.
[47:24.51]As we explore them, so we gain not only understanding, but power.
[47:32.63]It's not just the future of the whale that today lies in our hands
[47:37.66]it's the survival of the natural world in all parts of the living planet.
[47:45.03]We can now destroy, or we can cherish.
[47:51.88]The choice is ours.
在北极边缘有着大片针叶树林，那是矮小的针叶科树木寂静的世界。那些树或许真的很矮，但在高空拍摄下，树林显示出其真实的大小。世界有1/3的树木都生长在这里，在短暂的夏季里，这些树木制造了大量的氧气足以改变的大气的成份。在加利福尼亚有一棵叫做 General Sherman的巨型美洲杉，它是目前世界上最大的生物，比蓝鲸足足大上10倍。而世界上最古老的生物则是狐尾松了，活了有4000多年，比金字塔还要古老。马达加斯加的猴面包树则是世界上最奇特的树种。
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