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00:00Nuestro planeta es el más grande puzzle de vivienda en el universo.
00:05Un colección de mundos dentro de mundos.
00:09Cada uno un ecosistema de un ecosistema sincronizado,
00:12con la vida.
00:17Pero ¿cómo funcionan?
00:20El intercambio web de relaciones y el influencio de los naturales
00:26makes each micro-world complex and unique.
00:33So, to discover their secrets, we need to explore them one by one,
00:39untangle their interlocking pieces,
00:43and ultimately reveal the vital piece,
00:46the key to life itself,
00:50hidden deep within each of nature's micro-worlds.
00:56Our most northern micro-world sits well within the Arctic Circle.
01:09The Arctic, at the top of our planet,
01:13is covered in a permanent cap of ice.
01:16This close to the North Pole, the sea is nearly always frozen.
01:29Temperatures can be well below minus 50.
01:32In winter, the sun does not rise for three and a half months,
01:43staying just below the horizon
01:44and casting everything in an eerie blue half-light.
01:49Even when the sun does appear above the horizon,
01:56for much of the year the rays are too weak
01:58to be any use for primary production.
02:06But there is one area of the Arctic Circle that's different.
02:09It looks barren, but in Svalbard there are more polar bears than humans.
02:27It's home to the most northerly population of large herbivores in the world.
02:31And for its latitude, it's unusually rich in life.
02:39So what makes Svalbard so different to the rest of the Arctic?
02:46To understand this, we need to look at what makes this micro-world tick.
02:51Unravel the working parts that make this place so special,
02:55both the animals and the environment.
02:57And to do that means understanding how the animals that live here
03:04manage through the seasons.
03:09When looking at the animals in this micro-world,
03:11the best place to start
03:12is at the very top.
03:21How can a place seemingly locked in ice
03:23support so many of the world's largest land predator?
03:27The polar bear.
03:35The bears hunt out on the thick sea ice.
03:38But if the weather gets too bad to hunt,
03:46which it can here for weeks,
03:48the bears have the ability to curl up
03:50and slip into a sort of mini hibernation
03:52and ride it out,
03:54without doing too much damage
03:56to their energy reserves.
03:57This trick can be the difference between life and death.
04:09And the reason they patrol the sea ice
04:12is the type of food they eat.
04:14Their favourite food is the ringed seal.
04:24The ringed seal can live out on the ice all year round,
04:28using their claws to keep holes open in the ice,
04:33so that if danger appears,
04:35they have an escape hatch.
04:51To be able to survive in this freezing water,
04:54the seals put on a thick layer
04:56of warm, fatty blubber.
05:04And this energy-rich blubber
05:06is what the bears are after.
05:08But their problem is getting their paws on it.
05:27The seals give birth to their pups
05:29out on the freezing ice.
05:33A risky business with bears about.
05:38Bears use their nose to find food.
05:47They can pick up the scent of a seal
05:49buried under a metre of snow
05:51from nearly a kilometre away.
05:55They are the apex predators,
05:58the kings of our microworld.
06:03Weighing up to a thousand kilos,
06:05they can run at up to 60 kilometres an hour.
06:08The bears might be king out here,
06:17but only 2% of bear hunts are successful.
06:19But with a food source this rich,
06:36a 2% success rate is just enough to survive.
06:40Predation is just nature's way of keeping the system in balance.
06:56Predators keep prey populations fit and healthy.
07:00And to live here, you really do need to be fit and healthy.
07:06The bears walk such a thin line
07:11that they only eat the blubbery, energy-rich parts of the seal.
07:17Not wasting time on the other parts of the seal
07:20that don't give them the maximum return for their effort
07:22before moving on to find more.
07:25Arctic foxes have learnt that following polar bears pays off.
07:37The foxes clean up the meat that the bears don't bother with.
07:46It seems counterintuitive,
07:48but if you're an Arctic fox,
07:51out here the best place to be
07:53is right behind one of the world's most dangerous predators.
07:56Without the bears and their picky habits,
08:03the foxes would struggle to survive.
08:13The bears have shown us how they do it at the top.
08:17But what about the bottom of the food chain?
08:20Where are the primary producers?
08:22To find them, we have to follow
08:26another of Sfarbad's tough winter residents.
08:30Reindeer.
08:34Our microworld has the most northerly population
08:37of large herbivores in the world.
08:40And they're literally scraping to get by.
08:45These reindeer have evolved into a subspecies.
08:50Unlike their mainland cousins,
08:52they're able to digest enough of the tough vegetation
08:54they find here in winter to survive.
08:59They also have shorter legs,
09:02longer fur,
09:03and most importantly,
09:05the ability to put on thick fat reserves.
09:11These adaptations are great for the cold,
09:14but mean they're not good runners,
09:16which sounds disastrous with polar bears about.
09:18But actually,
09:22the bears very rarely hunt them.
09:31There is vegetation here underneath the ice,
09:34but it's hard to get to.
09:37And conditions here are too harsh for most plants.
09:40For the reindeer of Sfarbad,
09:46starvation is the main cause of death.
09:48To survive here,
09:52the reindeer,
09:53just like the ringed seals,
09:55have to depend on their fat reserves.
10:01But you can't build up fat reserves
10:03with such little food.
10:06So there must be times of plenty.
10:09And that is one of the things
10:12that makes Sfarbad so different
10:14to other Arctic locations.
10:22Because for just eight weeks of the year,
10:25something truly fabulous happens in Sfarbad.
10:30Summer.
10:30Spring and autumn do happen.
10:38But the sun stays so low in the sky,
10:41its rays only skim the surface
10:43and lack the intensity needed
10:45to be of any use to the primary producers.
10:50But as summer gets closer,
10:52the sun rises higher in the sky,
10:55the temperature increases,
10:57and the sea ice starts to melt.
10:59It's the signal for millions of seabirds
11:06to fly in from the south to breed.
11:13The short summer means that
11:15by the time they've arrived,
11:16found a mate,
11:17and hatched their eggs,
11:18there will only be three weeks left
11:20to rear their young
11:21before they have to head south again,
11:23before winter once more closes in.
11:29So how do they manage this so quickly?
11:34Well, the answer is that summer here
11:36has 24 hours of sunlight a day,
11:39and they use every minute of it.
11:49Both the males and the females
11:51bring food back to their growing chick
11:53almost constantly.
11:55The threat of the returning ice
11:57is an ever-present deadline.
12:01They've become absolute specialists
12:03in collecting as much food as possible
12:05as quickly as possible.
12:07These guillemots can die to 130 metres
12:12and hold their breath for up to three minutes
12:14in the search for food.
12:19But why, if there's such a tight time limit,
12:21do they come to Svalbard in the first place?
12:23The first things to react
12:32to the winter's weakening grip
12:34are tiny organisms called phytoplankton.
12:40They combine the sun's light
12:42and carbon dioxide found in the seawater
12:44to photosynthesise like plants.
12:47And they start doing this
12:49even under the ice,
12:51forming a greeny-brown crust.
12:53And as more sea ice melts
13:02and the sun gets higher in the sky,
13:04the phytoplankton blooms
13:06on a monumental scale.
13:11These are the marine equivalent of grass
13:13and are the primary producers.
13:18And these feed the next link on the food chain,
13:22millions of crustaceans
13:23which move around grazing
13:24like tiny underwater cows.
13:28They feed the fish,
13:30which feed the birds,
13:31and the seals,
13:32and so on right up to the top,
13:35the polar bear.
13:36The melting ice is good news for most,
13:43but not for the bears.
13:51This is the start
13:52of the bears' lean times.
13:54Now it's their turn to rely on their fat reserves
14:01to survive.
14:05Their Latin name means sea bear,
14:07but without the sea ice to hunt on,
14:10the advantage has turned to the seals
14:12fishing out in the open sea.
14:14But all this disappearing snow
14:27and melting ice
14:28has a positive impact
14:30on almost everything else
14:31within our microworld.
14:33As the ground thaws,
14:45plants burst into life,
14:47joining in the sprint
14:49to cram a full life cycle
14:51into this tiny window of opportunity.
14:54The most prolific meadows
15:02are found below the seabird colonies,
15:05fed by the tons of natural fertilizer
15:07in the form of bird droppings.
15:10So even Svabard's flowering plants
15:13are directly benefiting
15:14from the rich seas
15:15surrounding this island.
15:16As do the reindeer
15:23that come to these meadows
15:24to feed on the new,
15:25energy-rich growth
15:26fed by the bird colonies.
15:30The reindeer are in the same race
15:32as is all life here
15:34to make the absolute most of summer.
15:38This is their only chance
15:40to build the fat reserves
15:41they'll depend upon
15:42to see them through another winter.
15:44Nothing distracts them.
15:46Although feeding so close
15:52to the bird colonies
15:53has its dangers.
15:56Arctic skewers,
15:57ground-nesting birds,
15:59don't take kindly
16:00to big, clumsy reindeer
16:01near their eggs.
16:03Their sharp beaks
16:04can cause real damage.
16:06The problem is
16:07the reindeer
16:07are not really built to run.
16:11They're so specialised
16:12to cold weather
16:13that even the shortest run
16:15leaves them hot and boggled.
16:16The areas around
16:21the bird colonies
16:21are also a focus
16:23for the foxes
16:23which are also
16:27snatching this
16:28once-a-year chance
16:29to raise a family.
16:36And with eight
16:37hungry mouths to feed
16:38it's a relentless job.
16:49But winter will come around
16:51so fast
16:52that even with both
16:53the male and female
16:54working flat out
16:55it's likely only two cubs
16:57will survive
16:58to become adults.
16:59Although there might be
17:03a lot of food
17:04in our arctic micro-world
17:05right now
17:06it's apparent
17:08that in this
17:08boom-and-bust ecosystem
17:09these animals
17:11are not rolling
17:12in the good times.
17:13They're gambling
17:14on the short summer
17:15to provide.
17:19So how do the animals here
17:21cope with pressure
17:23like this?
17:26Well, they're forced
17:27to take risks.
17:29And as the days
17:30once more get shorter
17:31the hungry bears
17:33start to take
17:33some big risks.
17:37Without the ice
17:38they have no way
17:39of getting to the seals.
17:40It's hard to imagine
17:47a polar bear
17:48meeting its match
17:49on land
17:49but at times
17:51desperation
17:52drives the bears
17:53to take on
17:54some unusual opponents.
18:02Walruses can be
18:03three times as heavy
18:05as an adult polar bear.
18:07Their tusks
18:08can weigh up to
18:0810 pounds
18:09and measure
18:10a metre long
18:11and with one and a half
18:13tons of mammal
18:14behind them
18:14they also make
18:15formidable weapons.
18:23Apex predators
18:24like the polar bears
18:25need to be on top form
18:26to hunt.
18:28They need to use
18:29their energy wisely
18:30balancing the risk
18:32they take
18:32against the reward
18:34they stand to gain
18:35from a successful hunt.
18:36The polar bear
18:40might be king
18:40of our micro world
18:41but even he
18:43lives his life
18:44on the edge
18:45at times
18:45and on this occasion
18:48the gamble
18:49has not paid off.
18:54All the animals
18:55have to balance
18:56the potential benefit
18:57against the possible loss.
18:59in general
19:01the rewards
19:02outweigh the risk
19:03but there's a fine line
19:07that separates success
19:08from failure
19:09and if you've only got
19:14three weeks
19:15to rear your young
19:16winter coming a week early
19:18would spell disaster
19:20so the birds here
19:23are balancing
19:24right on the edge
19:25so why do they
19:29take the risk?
19:31well it's because
19:32Svarbad is unique
19:34and for this short period
19:35there's a lot of food
19:37guaranteed
19:37but they have to
19:42get out of here
19:43before the ice returns
19:44in a matter of days
19:46and this means
19:48pushing your child
19:49off a 300 meter cliff
19:51before it can fly
19:53the adults follow them
20:03calling all the way
20:05but it's a long way down
20:11when they've never
20:12tried their wings before
20:16getting to the water
20:26is only the first challenge
20:28with winter now
20:33approaching fast
20:34they've got to leave
20:35the trouble is
20:38that where they want
20:39to go to
20:39is 1200 miles away
20:41and the only way
20:44to get there
20:45is to swim
20:46some don't even
20:49make it as far
20:50as the sea
20:50soft bodies
20:53and feathers
20:53mean they can
20:54literally bounce
20:55without sustaining
20:56serious injury
20:57but they do have
20:59to finish the last bit
21:00on foot
21:01and some land
21:05a long way
21:06from the sea
21:07and in a micro world
21:14on a deadline
21:14not everyone
21:16can win
21:16when gambling
21:17when life is so finely tuned
21:24one creature's loss
21:26is another's game
21:28for this family of foxes
21:34this final feast
21:35could be the difference
21:36between surviving
21:37this year's winter
21:38and not
21:39even with eight hungry mouths
21:43to feed
21:44the foxes can't eat
21:45all the birds they collect
21:46so they store them
21:48these larders full of food
21:55help the foxes hedge their bets
21:56against the winter
21:57when there's nothing else to eat
21:59with such long light days
22:07you can get a lot done
22:09so is this length of day
22:12the key to a high level
22:14of productivity
22:14in our micro world
22:16sunlight after all
22:18is the origin
22:19of all energy on earth
22:20converted into food
22:22by those
22:22that can photosynthesize
22:24like those phytoplankton
22:26off Svarbad's coast
22:27all the other areas
22:39this far north
22:39have the same amount
22:40of sunlight
22:41but only the waters
22:42around Svarbad
22:43can claim to be responsible
22:45for 50% of the arctic's
22:47entire primary production
22:49so what is going on here
22:53that makes this place
22:54so special
22:55we need to know
23:01what phytoplankton gets
23:03in Svarbad
23:03that it doesn't get
23:05anywhere else
23:05besides sunlight
23:12the phytoplankton
23:14also needs other substances
23:15like nitrates
23:17and phosphates
23:18to flourish
23:18and these are hard to find
23:20at the sea's surface
23:21this is because
23:26they generally sink to the bottom
23:27and stay there
23:28so how do the primary producers
23:33get at it
23:34if it's all trapped
23:36if it's all trapped
23:36at the bottom of the sea
23:37incredibly the answer
23:43to this crucial question
23:44comes from the Caribbean
23:46and it holds the secret
23:50to what makes Svarbad
23:53so different
23:54a major force
24:05in the Atlantic
24:06is the Gulf Stream
24:07a flow of warm water
24:10that moves from the south of Florida
24:12north up the coast of America
24:14crosses the ocean
24:15and helps to keep the UK
24:17and northern Europe
24:18warm and wet
24:19its most northerly arm
24:22reaches Svarbad
24:23warming the waters
24:25in our microworld
24:26by only a few degrees
24:27but enough
24:28to help melt the ice
24:30this warm current
24:35collides with cold water
24:36flowing from the Arctic
24:37and together
24:38like a spoon
24:39in a giant bowl of soup
24:40they stir up the bottom
24:42causing the nitrates
24:43and phosphates
24:44to come to the surface
24:45and it's this rich upwelling
24:59that really kicks off
25:00Svarbad's phytoplankton bloom
25:02the meeting of these two currents
25:15holds the key
25:16to the unique success
25:18of this chilly microworld
25:20the phytoplankton
25:25couldn't bloom at all
25:26without the sun
25:26and this far north
25:30the sun couldn't reach
25:32into the waters
25:32without the gulf stream
25:34melting the ice
25:35and there wouldn't be
25:38enough fuel to feed it all
25:39without the collision
25:41and mixing
25:42of the currents
25:43and without this incredible level
25:50of primary production
25:51at the bottom of the food chain
25:52none of the animals
25:54would be able to take
25:55the gamble
25:55of living here
25:56at all
25:57and so productive
26:00is this microworld
26:02that it supports
26:03the largest land predator
26:04on earth
26:05the bears gamble so heavily
26:10on this environment
26:11that they've become
26:12too specialised
26:13to live anywhere else
26:14they rely on the food web
26:18below them
26:18and the frozen sea
26:20to get at it
26:21but the bears don't just get by
26:28here in Sparbard
26:29they thrive
26:30and that's because
26:32the females can build up
26:34enough of a fat reserve
26:35to be able to live
26:36under the snow
26:37for six months of the year
26:39eating nothing at all
26:40and the reason they do this
26:42becomes obvious
26:44in spring
26:45as if not eating
26:47for half the year
26:48wasn't enough
26:49she's also been using
26:50her own body
26:51to feed her two new cubs
26:53as well
26:54now they're ready
26:58to face the new challenges
26:59that lie in our
27:00boom and bust microworld
27:02luckily while they've been buried
27:07their favourite meal
27:08has been working hard
27:09on its fat reserves
27:10and some of these
27:12will feed the next generation
27:13of bears
27:14continuing to keep
27:17our microworld in balance
27:18from the top down
27:20so this web of interconnectivity
27:25in our most northern microworld
27:27is all dependent
27:28on the tiny primary producers
27:30at the bottom of the food chain
27:31that can bounce into life
27:33and make the most
27:35of the returning sunlight
27:36but without the specific
27:43set of conditions
27:44found in spa barred
27:45the primary producers
27:46simply couldn't work
27:48on the scale they do
27:49and without them
27:52one of the most productive areas
27:54in the world
27:55could not exist
27:56spa barred shows us
28:06on a massive scale
28:07the fundamental principle
28:09of how microworlds work
28:11it's not only the creatures
28:14that live in them
28:14that make them tick
28:15it's also the processes
28:17that shape our entire earth
28:19commonwealth games extra
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