1
00:00:03,360 --> 00:00:04,880
In this series,

2
00:00:04,880 --> 00:00:08,400
I have travelled the length and
breadth of the Great Barrier Reef...

3
00:00:12,760 --> 00:00:16,000
..and used the latest techniques
to watch its wildlife.

4
00:00:25,560 --> 00:00:29,200
But the reef has
one more story to tell.

5
00:00:32,000 --> 00:00:34,680
The residents of this marine paradise

6
00:00:34,680 --> 00:00:38,720
have seen their habitat change
rapidly within the last few decades.

7
00:00:40,360 --> 00:00:42,800
And time is running out for them.

8
00:00:47,640 --> 00:00:50,920
The Barrier Reef is facing
one of the most serious challenges

9
00:00:50,920 --> 00:00:53,360
to its continued existence -

10
00:00:53,360 --> 00:00:55,200
the effect of human beings.

11
00:00:57,040 --> 00:00:58,800
But there is hope.

12
00:01:00,680 --> 00:01:03,680
This time, our research vessel,
the Alucia,

13
00:01:03,680 --> 00:01:06,400
will be taking me to meet
teams of scientists

14
00:01:06,400 --> 00:01:09,800
who are developing new ways
to try and save it.

15
00:01:11,240 --> 00:01:13,840
And I'll be going to
its deepest parts,

16
00:01:13,840 --> 00:01:15,880
where new discoveries are being made

17
00:01:15,880 --> 00:01:18,760
that might hold clues
to its survival.

18
00:01:18,760 --> 00:01:21,880
Nobody has ever dived
as deep as this before

19
00:01:21,880 --> 00:01:23,400
on the Great Barrier Reef.

20
00:01:25,480 --> 00:01:30,320
This is one of the greatest and most
important ecosystems on the planet -

21
00:01:30,320 --> 00:01:33,240
and what happens here affects us all.

22
00:01:34,640 --> 00:01:38,280
So, what does the future hold
for this complex wonder?

23
00:01:50,520 --> 00:01:53,320
I'm travelling along
Australia's north east coast

24
00:01:53,320 --> 00:01:55,120
to look at one of the greatest

25
00:01:55,120 --> 00:01:58,760
and most splendid natural treasures
that the world possesses -

26
00:01:58,760 --> 00:02:01,640
a chain of tropical islands
and coral reefs

27
00:02:01,640 --> 00:02:04,840
that lies between the coast
and the open ocean.

28
00:02:11,560 --> 00:02:14,600
I will never forget
the first time I came here.

29
00:02:18,080 --> 00:02:20,080
YOUNGER DAVID: 'And what
a world this was -

30
00:02:20,080 --> 00:02:22,960
'beneath me lay an endless
landscape of coral,

31
00:02:22,960 --> 00:02:25,960
'of every conceivable
colour and shape.'

32
00:02:37,760 --> 00:02:42,000
It was unimaginable then to think
that we might ever lose the reef.

33
00:02:46,400 --> 00:02:50,320
But now, I've returned, and
I can see that the reef is changing.

34
00:02:53,840 --> 00:02:57,960
In the last 30 years, almost
half the coral has disappeared.

35
00:03:01,680 --> 00:03:05,800
The greatest concern now is that
we might lose the reef altogether.

36
00:03:16,320 --> 00:03:19,400
Parts of the Great Barrier Reef
still remain a mystery.

37
00:03:19,400 --> 00:03:22,040
Its immense size and remote depths

38
00:03:22,040 --> 00:03:24,800
make it extremely
difficult to explore.

39
00:03:28,760 --> 00:03:32,160
But today, exciting new technology
has made it possible

40
00:03:32,160 --> 00:03:36,480
to survey the entire reef
from top to bottom.

41
00:03:36,480 --> 00:03:39,320
And that is revealing
extraordinary things

42
00:03:39,320 --> 00:03:42,800
about the way in which the reef
itself has evolved over time.

43
00:03:44,880 --> 00:03:47,040
By looking into the reef's past,

44
00:03:47,040 --> 00:03:49,760
we may discover something
about its future.

45
00:03:51,480 --> 00:03:55,160
So, I'm meeting marine geologist
Dr Robin Beaman.

46
00:03:57,760 --> 00:03:59,720
'He is on board the Alucia

47
00:03:59,720 --> 00:04:02,640
'and shows me some of his
remarkable discoveries.'

48
00:04:04,120 --> 00:04:07,240
This is a depth model of
the Great Barrier Reef -

49
00:04:07,240 --> 00:04:09,360
of the entire
Great Barrier Reef.

50
00:04:09,360 --> 00:04:11,800
And there's a whole lot
of different tools we use,

51
00:04:11,800 --> 00:04:14,040
the main one being
multibeam echosounders,

52
00:04:14,040 --> 00:04:16,680
so it gives you
a scan of the seafloor

53
00:04:16,680 --> 00:04:21,160
and we can actually map great
areas of the continental shelf.

54
00:04:21,160 --> 00:04:23,600
This white part is land?

55
00:04:23,600 --> 00:04:24,720
That's right.

56
00:04:24,720 --> 00:04:29,280
So, everything that's coloured
rainbow colours is under water.

57
00:04:29,280 --> 00:04:33,120
'By combining computer modelling
and deep sea surveying,

58
00:04:33,120 --> 00:04:35,360
'Beaman has discovered new evidence

59
00:04:35,360 --> 00:04:38,720
'that the reef has already
experienced great changes.'

60
00:04:41,360 --> 00:04:43,480
As a scientist -
as geological scientists -

61
00:04:43,480 --> 00:04:45,720
we're trying to understand
how the Great Barrier Reef

62
00:04:45,720 --> 00:04:47,800
has responded to changes in the past

63
00:04:47,800 --> 00:04:50,840
and there are clues there as to what
the Great Barrier Reef has done,

64
00:04:50,840 --> 00:04:54,560
so if I zoom back,
you can see, geologically,

65
00:04:54,560 --> 00:04:57,040
it's gone through some
dramatic changes.

66
00:05:00,560 --> 00:05:04,440
Beaman's scans showed
traces of an ancient reef

67
00:05:04,440 --> 00:05:07,440
that thrived over the last
half million years

68
00:05:07,440 --> 00:05:10,920
and is now hidden along the edge
of this great drop-off.

69
00:05:13,360 --> 00:05:17,400
This earlier reef existed
long before the one we know today.

70
00:05:17,400 --> 00:05:20,040
It lay up to 70 metres deep

71
00:05:20,040 --> 00:05:23,720
and stretched nearly unbroken
for more than 500 miles.

72
00:05:26,680 --> 00:05:30,160
It's been described as
the world's largest fossil.

73
00:05:32,320 --> 00:05:35,480
This is what the older
Great Barrier Reef looked like.

74
00:05:35,480 --> 00:05:37,320
And we call these "drowned reefs" -

75
00:05:37,320 --> 00:05:40,360
they're drowned in the sense that
the water over them is so deep

76
00:05:40,360 --> 00:05:42,160
that the reef no longer grows.

77
00:05:44,320 --> 00:05:47,480
These ancient reefs were drowned
by dramatic climate changes

78
00:05:47,480 --> 00:05:49,600
that caused sea levels to rise.

79
00:05:51,320 --> 00:05:54,400
This last happened less
than 14,000 years ago.

80
00:05:56,160 --> 00:05:59,280
So, water released from
the melting icecaps

81
00:05:59,280 --> 00:06:02,720
is going to start flooding
across here, is it? That's right.

82
00:06:02,720 --> 00:06:05,600
The sea level was high enough
to actually inundate

83
00:06:05,600 --> 00:06:08,000
and cover these old limestone hills

84
00:06:08,000 --> 00:06:11,240
and created the Great Barrier Reef
that we know today.

85
00:06:11,240 --> 00:06:14,200
So, the changes that
we're seeing going on now

86
00:06:14,200 --> 00:06:17,320
are nothing new, in terms of change.

87
00:06:17,320 --> 00:06:20,600
I mean, the Barrier Reef
has always been changing.

88
00:06:20,600 --> 00:06:22,200
We do find it's quite robust.

89
00:06:22,200 --> 00:06:24,080
It has actually reformed,

90
00:06:24,080 --> 00:06:29,320
despite these catastrophic changes
that have occurred.

91
00:06:30,600 --> 00:06:35,480
It's been exposed and flooded
at least four times that we know of.

92
00:06:35,480 --> 00:06:37,280
To us, it's astounding.

93
00:06:40,720 --> 00:06:44,160
This new insight into
the ancient history of the reef

94
00:06:44,160 --> 00:06:47,680
shows that, given enough time,
it can regenerate.

95
00:06:52,280 --> 00:06:55,560
It seems that if seawater
is clear and warm,

96
00:06:55,560 --> 00:06:58,200
simple organisms will
eventually evolve

97
00:06:58,200 --> 00:07:00,840
that can build limestone
homes to protect themselves

98
00:07:00,840 --> 00:07:02,680
from the waves and their enemies.

99
00:07:05,040 --> 00:07:09,480
But most of these events started long
before human beings appeared on Earth

100
00:07:09,480 --> 00:07:12,120
and took many thousands
of years to complete.

101
00:07:15,360 --> 00:07:19,200
We now know the reef has
dwindled and recovered

102
00:07:19,200 --> 00:07:22,160
many times in its long history,

103
00:07:22,160 --> 00:07:27,040
but it also has to withstand
a major change every 24 hours,

104
00:07:27,040 --> 00:07:30,080
as the tide retreats and comes back.

105
00:07:34,640 --> 00:07:38,000
At low tide, the water
drains away very quickly,

106
00:07:38,000 --> 00:07:41,640
leaving the topmost community
of creatures dangerously exposed.

107
00:07:47,520 --> 00:07:49,680
Some are washed out with the tide.

108
00:07:56,040 --> 00:07:57,880
Others swim to safety.

109
00:08:00,320 --> 00:08:02,760
But the coral polyps can't move.

110
00:08:07,320 --> 00:08:09,760
Temperatures on
the surface of the reef

111
00:08:09,760 --> 00:08:12,720
can now reach a scorching
30 degrees centigrade.

112
00:08:15,680 --> 00:08:18,320
The exposed corals
could easily dry out

113
00:08:18,320 --> 00:08:21,240
and be damaged by intense
ultraviolet rays.

114
00:08:23,680 --> 00:08:26,440
But corals have ways
of protecting themselves.

115
00:08:28,760 --> 00:08:32,520
When exposed to air, they produce
huge amounts of mucus,

116
00:08:32,520 --> 00:08:35,480
which keeps them wet
and acts like a sunscreen.

117
00:08:37,520 --> 00:08:42,280
This remarkable slime actually
increases its UV resistance,

118
00:08:42,280 --> 00:08:44,920
becoming stronger
if the temperatures soar.

119
00:08:46,840 --> 00:08:51,520
So, the coral manages to survive for
the few hours that it's out of water.

120
00:08:55,040 --> 00:08:59,640
But there's one fish that manages to
turn this exposure to its advantage.

121
00:09:12,240 --> 00:09:17,320
The epaulette shark remains on the
reef even when the tide goes out.

122
00:09:17,320 --> 00:09:19,640
Of course, with so little water,

123
00:09:19,640 --> 00:09:22,560
it doesn't get as much oxygen
as it requires normally,

124
00:09:22,560 --> 00:09:27,200
but it deals with that possibility
by shutting off a part of its brain

125
00:09:27,200 --> 00:09:29,360
and so, reducing its oxygen demands.

126
00:09:30,960 --> 00:09:34,960
As the retreating tide exposes
the topmost branches of the corals,

127
00:09:34,960 --> 00:09:39,040
the shark remains in the little pools
between them for as long as it can.

128
00:09:41,840 --> 00:09:46,000
And then, it sets off
to try and find food -

129
00:09:46,000 --> 00:09:50,760
shrimps, crabs and small worms
that live on the reef.

130
00:09:50,760 --> 00:09:54,880
And it does that by exploiting
another talent it has.

131
00:09:54,880 --> 00:09:56,920
It can, in effect, walk.

132
00:10:09,840 --> 00:10:13,760
It may be slow-going, but the
little shark manages to make its way

133
00:10:13,760 --> 00:10:17,840
between the rocky pools to look for
prey that may be imprisoned in them.

134
00:10:25,960 --> 00:10:27,600
It has the run of the place,

135
00:10:27,600 --> 00:10:31,040
until the tide returns once more
to flood the reeftop.

136
00:10:45,640 --> 00:10:49,320
So, the inhabitants of the reef,
each in its own way,

137
00:10:49,320 --> 00:10:52,680
deal with the daily hazards
brought by exposure.

138
00:10:59,320 --> 00:11:02,800
But there is one catastrophe
that can strike each year

139
00:11:02,800 --> 00:11:04,960
against which there is no defence.

140
00:11:13,200 --> 00:11:15,160
From November onwards,

141
00:11:15,160 --> 00:11:17,960
warm, moisture-laden winds
from the northwest

142
00:11:17,960 --> 00:11:21,200
sweep down across these tropic seas

143
00:11:21,200 --> 00:11:23,640
and it's then that cyclones form.

144
00:11:27,080 --> 00:11:31,560
They are, in fact, the biggest
killers of the reef's corals.

145
00:11:33,200 --> 00:11:38,080
But that doesn't mean that the
corals are permanently destroyed.

146
00:11:38,080 --> 00:11:40,880
Their resilience once more
comes apparent.

147
00:11:45,040 --> 00:11:48,200
And there's an extraordinary
example of that

148
00:11:48,200 --> 00:11:50,240
in the most unlikely of places.

149
00:12:06,720 --> 00:12:10,160
This is the wreck
of the SS Yongala.

150
00:12:13,640 --> 00:12:16,480
It was sunk by a cyclone in 1911.

151
00:12:22,240 --> 00:12:27,000
It lies 30 metres below the surface
on a barren, sandy plain...

152
00:12:30,720 --> 00:12:34,160
..miles away from
any natural coral reefs.

153
00:12:38,720 --> 00:12:41,440
By the time it was discovered,
decades later,

154
00:12:41,440 --> 00:12:43,880
it had become an artificial reef...

155
00:12:46,400 --> 00:12:50,360
..and had been colonised by
an extraordinary variety of life.

156
00:12:56,480 --> 00:12:59,360
It was an oasis
in the featureless ocean.

157
00:13:15,800 --> 00:13:18,040
But in the century since it sank,

158
00:13:18,040 --> 00:13:21,680
the wreck has been hit
repeatedly by more cyclones.

159
00:13:26,200 --> 00:13:28,760
The waters here are not deep

160
00:13:28,760 --> 00:13:33,480
so the turbulence created by
a cyclone can reach the sea floor.

161
00:13:42,800 --> 00:13:45,240
THUNDERCLAP

162
00:13:51,560 --> 00:13:54,200
Cyclones travelling
towards the coast

163
00:13:54,200 --> 00:13:57,000
can rip up hundreds
of miles of coral.

164
00:14:01,880 --> 00:14:05,760
Captain Trevor Jackson, who has been
diving on this wreck for decades,

165
00:14:05,760 --> 00:14:12,080
saw the devastating effects caused
in 2011 by a category five cyclone.

166
00:14:13,680 --> 00:14:16,120
Cyclone Yahtzee, a massive system,

167
00:14:16,120 --> 00:14:18,240
crossed the coast
just north of here.

168
00:14:18,240 --> 00:14:19,640
The cyclone was so large,

169
00:14:19,640 --> 00:14:22,640
it generated waves that exposed
the top of the Yongala.

170
00:14:28,080 --> 00:14:30,720
THUNDERCLAP

171
00:14:39,560 --> 00:14:41,240
There was a lifting action...

172
00:14:44,280 --> 00:14:45,960
..and in the process,

173
00:14:45,960 --> 00:14:48,920
this scoured the top of the reef
of all marine life.

174
00:15:00,560 --> 00:15:05,480
What was once a thriving ecosystem
was now an almost bare skeleton.

175
00:15:10,200 --> 00:15:12,800
But amazingly,
the reef on the Yongala

176
00:15:12,800 --> 00:15:15,520
began to repair itself within months.

177
00:15:20,920 --> 00:15:23,000
Green algae appeared on the wreck.

178
00:15:24,600 --> 00:15:27,920
Barnacles followed,
allowing corals to get a grip.

179
00:15:35,240 --> 00:15:39,200
And soon, a new community
had established itself.

180
00:16:04,400 --> 00:16:07,520
One of the things that makes
the Yongala so unique

181
00:16:07,520 --> 00:16:12,120
is the way it rejuvenates itself
after a major weather event.

182
00:16:12,120 --> 00:16:14,480
In the course of the last
four or five years,

183
00:16:14,480 --> 00:16:16,760
about 80% of the reef has re-grown.

184
00:16:25,360 --> 00:16:29,560
The story of the Yongala shows that
a coral reef can, remarkably,

185
00:16:29,560 --> 00:16:32,000
recover from natural disaster.

186
00:16:42,720 --> 00:16:45,760
And such recovery can be
surprisingly quick

187
00:16:45,760 --> 00:16:48,160
when a reef is healthy
and in balance.

188
00:16:51,280 --> 00:16:54,960
Most of the reef's inhabitants
depend on one another for survival.

189
00:17:11,240 --> 00:17:14,800
But it is the coral that is
the foundation of the reef

190
00:17:14,800 --> 00:17:18,840
and it plays a crucial role
in many of the relationships.

191
00:17:28,080 --> 00:17:31,720
This is the crown-of-thorns starfish.

192
00:17:33,560 --> 00:17:36,320
For it, coral is food

193
00:17:36,320 --> 00:17:39,600
and it will eat relentlessly
if not kept in check.

194
00:17:40,680 --> 00:17:43,080
But to other creatures,
like the guard crab,

195
00:17:43,080 --> 00:17:44,720
coral is home.

196
00:17:50,120 --> 00:17:53,080
The crab is prepared
to defend its patch

197
00:17:53,080 --> 00:17:56,280
from the carnivorous starfish
at all costs.

198
00:18:01,160 --> 00:18:02,880
The crown-of-thorns, however,

199
00:18:02,880 --> 00:18:05,880
is much larger than most
other starfish on the reef,

200
00:18:05,880 --> 00:18:10,200
so the tiny crab is forced to
take a more stealthy approach.

201
00:18:14,800 --> 00:18:18,760
Hidden within the coral,
it waits for its moment to attack.

202
00:18:33,440 --> 00:18:37,120
The starfish has left itself
dangerously exposed,

203
00:18:37,120 --> 00:18:39,280
but the crab is cautious.

204
00:18:44,280 --> 00:18:46,960
When it can, the crab
uses its powerful pincers

205
00:18:46,960 --> 00:18:51,120
to snip at the starfish's
spines and tube-like feet...

206
00:19:04,160 --> 00:19:07,400
..before retreating back
into the safety of the coral.

207
00:19:09,360 --> 00:19:11,480
The crab has won this battle.

208
00:19:14,200 --> 00:19:16,760
But recently, something has changed

209
00:19:16,760 --> 00:19:18,680
and the balance has been upset.

210
00:19:22,720 --> 00:19:26,120
The number of crown-of-thorns
has increased dramatically

211
00:19:26,120 --> 00:19:28,840
and they've become
a big problem on the reef.

212
00:19:34,800 --> 00:19:36,440
To find out more,

213
00:19:36,440 --> 00:19:40,920
the Alucia is taking me to a research
station in the far north of the reef.

214
00:19:49,960 --> 00:19:54,760
It's situated on Lizard Island, where
we can observe this problem up close.

215
00:20:00,160 --> 00:20:03,480
Lizard is surrounded by some of
the most spectacular reefs

216
00:20:03,480 --> 00:20:05,120
on the entire barrier.

217
00:20:07,120 --> 00:20:11,000
But they are under attack
from the coral-eating starfish.

218
00:20:12,720 --> 00:20:15,240
And at the island's research station,

219
00:20:15,240 --> 00:20:19,240
they've been studying why we might be
seeing more of them than we used to.

220
00:20:29,040 --> 00:20:31,280
They have an extraordinary ability

221
00:20:31,280 --> 00:20:36,760
to suddenly increase vastly
in numbers, like a plague.

222
00:20:36,760 --> 00:20:40,960
There have been three such plagues
since the 1960s

223
00:20:40,960 --> 00:20:42,480
and, unfortunately,

224
00:20:42,480 --> 00:20:45,720
it seems as though we're in
the middle, now, of a fourth.

225
00:20:47,480 --> 00:20:51,400
You might think that these plagues
are just another natural disaster

226
00:20:51,400 --> 00:20:54,560
that the reef has had to
withstand, like cyclones.

227
00:20:54,560 --> 00:20:57,320
There are reasons to
suppose that, in fact,

228
00:20:57,320 --> 00:21:00,960
the plagues have been
affected by human activity -

229
00:21:00,960 --> 00:21:05,840
either through an accumulation of
run-off of fertilisers from the land

230
00:21:05,840 --> 00:21:09,680
that creates more food
for the young starfish,

231
00:21:09,680 --> 00:21:11,720
or because we have overfished

232
00:21:11,720 --> 00:21:14,560
and so destroyed
the natural balance of the reef.

233
00:21:16,160 --> 00:21:19,240
The starfish outbreaks
have been responsible

234
00:21:19,240 --> 00:21:22,880
for over 40% of the coral
loss of the last 30 years.

235
00:21:24,200 --> 00:21:28,600
It's just one of the huge changes
here witnessed by Dr Charlie Veron.

236
00:21:30,400 --> 00:21:32,760
In 1972, Charlie was appointed

237
00:21:32,760 --> 00:21:36,720
the reef's first full-time
coral scientist.

238
00:21:36,720 --> 00:21:39,880
He's gone on to become
a world authority on coral

239
00:21:39,880 --> 00:21:43,000
and has identified a third
of the world's known species.

240
00:21:44,440 --> 00:21:49,000
He was one of the first scientists to
spend time in this underwater world

241
00:21:49,000 --> 00:21:51,800
and that was due to
a particular piece of technology.

242
00:21:53,600 --> 00:21:57,840
What we knew about corals
at the beginning of the scuba era

243
00:21:57,840 --> 00:21:59,840
was just almost nothing.

244
00:21:59,840 --> 00:22:02,840
So, scuba gear must have
changed things radically.

245
00:22:02,840 --> 00:22:04,280
It changed everything.

246
00:22:04,280 --> 00:22:06,960
When you went down
the face of a coral reef,

247
00:22:06,960 --> 00:22:10,800
you could see how corals fed,
how they fought each other,

248
00:22:10,800 --> 00:22:12,600
how they reproduced and still,

249
00:22:12,600 --> 00:22:14,880
we're only just scratching
the surface.

250
00:22:14,880 --> 00:22:17,160
Think of all the things that happen
in a rainforest,

251
00:22:17,160 --> 00:22:18,640
how much we know about it.

252
00:22:18,640 --> 00:22:22,000
We haven't got a thousandth
part of that information
on the coral reef yet.

253
00:22:22,000 --> 00:22:24,440
'But since Charlie's
first discoveries,

254
00:22:24,440 --> 00:22:27,000
'the reef has altered dramatically.'

255
00:22:27,000 --> 00:22:32,400
I've been going back to the
same spots 10, 20, 30, 40 years ago

256
00:22:32,400 --> 00:22:35,240
and every time I go back,

257
00:22:35,240 --> 00:22:39,080
I'm sickened by some of
the changes I've seen.

258
00:22:39,080 --> 00:22:41,480
Sometimes, I go back,
I know it's the same spot

259
00:22:41,480 --> 00:22:43,120
and I can barely recognise it.

260
00:22:43,120 --> 00:22:45,440
Some species have been wiped out
in the shallows now.

261
00:22:45,440 --> 00:22:47,600
It's already happened.

262
00:22:49,400 --> 00:22:53,480
What Charlie had witnessed were
the effects of mankind upon the reef.

263
00:22:57,760 --> 00:23:02,600
When I myself first visited the
Queensland coast almost 60 years ago,

264
00:23:02,600 --> 00:23:04,400
it was very different.

265
00:23:13,600 --> 00:23:16,880
Since then, like many
coastlines around the world,

266
00:23:16,880 --> 00:23:19,680
there has been a massive
increase in population

267
00:23:19,680 --> 00:23:22,000
and an explosion of industry.

268
00:23:36,720 --> 00:23:42,040
By 1975, the reef had been declared
a National Marine Park.

269
00:23:42,040 --> 00:23:45,480
It was the biggest one
of its kind in the world.

270
00:23:45,480 --> 00:23:48,960
But then, a new threat
began to be recognised -

271
00:23:48,960 --> 00:23:52,600
not only to the reef,
but to the world's oceans -

272
00:23:52,600 --> 00:23:54,040
climate change.

273
00:23:55,720 --> 00:23:59,080
THUNDERCLAPS

274
00:24:01,720 --> 00:24:05,560
There is more carbon dioxide
in our atmosphere now

275
00:24:05,560 --> 00:24:08,640
than there has been in 800,000 years.

276
00:24:11,600 --> 00:24:14,720
Industrialised nations
have been burning fossil fuels

277
00:24:14,720 --> 00:24:16,720
at an alarming rate.

278
00:24:18,640 --> 00:24:21,360
Global warming is slowly
heating up our planet

279
00:24:21,360 --> 00:24:24,040
and threatens to cause
huge problems for us all.

280
00:24:26,520 --> 00:24:31,880
Around 30% of the carbon dioxide
we produce is absorbed by the ocean.

281
00:24:35,240 --> 00:24:38,320
As a result, we're seeing
an increase in the temperature

282
00:24:38,320 --> 00:24:39,920
and acidity of our seas.

283
00:24:42,640 --> 00:24:45,800
Both are killing
the inhabitants of the reef.

284
00:24:51,080 --> 00:24:53,280
But how quickly is it being damaged?

285
00:24:56,560 --> 00:25:01,440
To find out, I'm heading to meet
Professor Ove Hoegh-Guldberg

286
00:25:01,440 --> 00:25:04,920
He's studying the effects
of climate change on coral.

287
00:25:09,640 --> 00:25:11,880
Ove is based on Heron Island,

288
00:25:11,880 --> 00:25:15,240
near the southern end
of the Great Barrier.

289
00:25:15,240 --> 00:25:19,520
Heron is a low, sandy island,
50 miles out from the mainland,

290
00:25:19,520 --> 00:25:21,160
right on the reef itself...

291
00:25:24,040 --> 00:25:27,240
..so its research station
is very well-placed.

292
00:25:28,840 --> 00:25:31,520
Here, Ove is carrying out
an experiment

293
00:25:31,520 --> 00:25:33,520
to see how the reef is going to cope.

294
00:25:34,560 --> 00:25:36,400
At the research station here,

295
00:25:36,400 --> 00:25:40,440
the experiment we're running is
really climate change sped up.

296
00:25:41,760 --> 00:25:45,560
Because it's often hard for people
to really get their heads around

297
00:25:45,560 --> 00:25:48,120
when you talk about
global change over decades

298
00:25:48,120 --> 00:25:50,280
and what might happen
to coral reefs.

299
00:25:50,280 --> 00:25:53,240
We have, essentially,
in these experiments, sped things up

300
00:25:53,240 --> 00:25:55,560
so that you can literally,
over a year,

301
00:25:55,560 --> 00:25:59,320
see the impacts of what might be
occurring over the next hundred.

302
00:26:03,160 --> 00:26:06,360
Each of these tanks contains
a miniature coral reef

303
00:26:06,360 --> 00:26:08,880
with the same species of coral.

304
00:26:08,880 --> 00:26:11,120
But each is being subjected to

305
00:26:11,120 --> 00:26:15,160
slightly different conditions
of temperature and acidity -

306
00:26:15,160 --> 00:26:18,960
the two factors that are most likely
to alter with climate change.

307
00:26:23,960 --> 00:26:28,200
Using these tanks, scientists
have shown that increasing acidity

308
00:26:28,200 --> 00:26:31,840
restricts hard corals from building
their limestone skeletons.

309
00:26:35,080 --> 00:26:37,000
And a rise in temperature -

310
00:26:37,000 --> 00:26:39,560
a single degree centigrade
warmer than normal -

311
00:26:39,560 --> 00:26:42,160
can cause corals
to become so stressed

312
00:26:42,160 --> 00:26:45,080
that they eject
the photosynthesising algae

313
00:26:45,080 --> 00:26:47,760
that enable them to grow
and give some colour.

314
00:26:52,960 --> 00:26:56,200
So they bleach,
turning ghostly white.

315
00:27:06,600 --> 00:27:08,400
If you go back in time,

316
00:27:08,400 --> 00:27:13,280
you can see the big swings between
ice ages and the warm periods

317
00:27:13,280 --> 00:27:15,520
where the Great Barrier Reef
disappears and regrows

318
00:27:15,520 --> 00:27:18,160
and that's happened numerous times.

319
00:27:18,160 --> 00:27:20,360
So, we've always had changes,

320
00:27:20,360 --> 00:27:24,880
but we're talking about changes
over 10,000 years, in those cases.

321
00:27:24,880 --> 00:27:29,000
But we're now seeing is
the equivalent in a few decades.

322
00:27:29,000 --> 00:27:32,000
And that, of course, is stretching
life's capacity to keep up.

323
00:27:38,680 --> 00:27:43,400
Organisms, ecosystems are falling
behind as the world changes,

324
00:27:43,400 --> 00:27:46,840
faster than it has in this
enormous amount of time.

325
00:27:52,240 --> 00:27:57,160
It's been shown here that a rise
of just two degrees centigrade

326
00:27:57,160 --> 00:28:00,200
will turn a healthy reef
into a decimated one.

327
00:28:01,640 --> 00:28:05,320
And such a rise will almost
certainly happen in these seas

328
00:28:05,320 --> 00:28:08,120
if we continue to do
what we are doing.

329
00:28:18,600 --> 00:28:21,000
As Ove's tests suggest,

330
00:28:21,000 --> 00:28:23,560
this man-made problem
has reached the point

331
00:28:23,560 --> 00:28:26,000
where it needs a man-made solution.

332
00:28:30,120 --> 00:28:32,320
I'm returning to mainland Australia

333
00:28:32,320 --> 00:28:35,240
to meet the scientists who are
approaching this problem

334
00:28:35,240 --> 00:28:37,000
in a radically new way.

335
00:28:39,240 --> 00:28:43,440
The Australian Institute of
Marine Science, AIMS,

336
00:28:43,440 --> 00:28:46,880
is based in northeast Queensland,
right on the coast.

337
00:28:50,160 --> 00:28:54,640
Here, pioneering research is pushing
the boundaries of coral science.

338
00:28:59,960 --> 00:29:03,840
Over three million litres
of filtered seawater

339
00:29:03,840 --> 00:29:06,440
are pumped through
these tanks every day.

340
00:29:07,640 --> 00:29:11,000
So, it's possible for scientists
to study the minute

341
00:29:11,000 --> 00:29:15,800
and often very complex changes
that can affect coral's health.

342
00:29:19,440 --> 00:29:22,080
So, here, they're also
conducting research

343
00:29:22,080 --> 00:29:24,360
to see whether it
might not be possible

344
00:29:24,360 --> 00:29:28,560
to devise techniques of restoring
damaged reefs back to health.

345
00:29:30,760 --> 00:29:34,880
In these tanks, they can simulate
the exact conditions of the reef.

346
00:29:36,840 --> 00:29:39,760
They've been so successful
that remarkably,

347
00:29:39,760 --> 00:29:43,480
the corals respond to the same
astronomic and seasonal rhythms

348
00:29:43,480 --> 00:29:45,080
as those out in the ocean.

349
00:29:49,080 --> 00:29:52,920
And that is proving useful for
one particular experiment.

350
00:29:55,440 --> 00:29:58,960
Corals are usually able to adapt
to changing circumstances,

351
00:29:58,960 --> 00:30:00,240
given enough time.

352
00:30:05,160 --> 00:30:08,480
And that is partly due to
the way they reproduce.

353
00:30:11,920 --> 00:30:14,080
After the first full moon in October,

354
00:30:14,080 --> 00:30:17,200
the great synchronised
coral spawning event begins.

355
00:30:38,160 --> 00:30:41,600
It's a wonderful,
annual rejuvenation.

356
00:30:48,080 --> 00:30:52,440
Hundreds of species release
sperm and eggs into the ocean.

357
00:30:56,120 --> 00:31:00,200
Just as pollen from plants is
blown far and wide by the wind,

358
00:31:00,200 --> 00:31:03,920
so coral spawn is swept away
by the ocean currents.

359
00:31:06,680 --> 00:31:10,280
And at the same time,
under the same moonlight,

360
00:31:10,280 --> 00:31:14,000
the corals will spawn here
in the laboratory tanks.

361
00:31:18,480 --> 00:31:22,120
Using red light, so as
not to disturb the process,

362
00:31:22,120 --> 00:31:24,720
scientists wait for
the moment of release.

363
00:31:38,960 --> 00:31:40,600
And when it finally happens,

364
00:31:40,600 --> 00:31:43,640
they move fast to collect
the sperm and the eggs.

365
00:31:48,480 --> 00:31:51,760
It's their one chance to get
all the samples they need

366
00:31:51,760 --> 00:31:53,720
for a year's worth of research.

367
00:31:56,880 --> 00:31:59,680
But what exactly are they
planning to do with them?

368
00:32:03,120 --> 00:32:07,800
Here, Dr Madeleine van Oppen has
been selectively breeding them,

369
00:32:07,800 --> 00:32:12,480
using much the same techniques that
we've used to produce crops on land

370
00:32:12,480 --> 00:32:15,520
that are resistant
to drought and disease.

371
00:32:15,520 --> 00:32:18,000
It's the first time that
selective breeding

372
00:32:18,000 --> 00:32:20,400
has been used in marine conservation.

373
00:32:24,480 --> 00:32:26,800
They release their
sperm and eggs in bundles

374
00:32:26,800 --> 00:32:29,760
and those bundles float
to the surface of the tank.

375
00:32:29,760 --> 00:32:33,480
We then agitate that to separate
the eggs from the sperm.

376
00:32:36,480 --> 00:32:38,080
And we use that to set up

377
00:32:38,080 --> 00:32:41,120
our specific in vitro
processes, basically.

378
00:32:45,000 --> 00:32:47,280
In the ocean, there is the potential

379
00:32:47,280 --> 00:32:50,400
for different species of coral
to breed with each other.

380
00:32:51,680 --> 00:32:53,680
So, here, scientists wonder

381
00:32:53,680 --> 00:32:56,840
if you might be able to
produce a new kind of coral

382
00:32:56,840 --> 00:33:00,440
that proves more successful in
the changing waters of the reef.

383
00:33:02,360 --> 00:33:04,680
The problem that corals
are facing now is that

384
00:33:04,680 --> 00:33:07,520
the change of the environment
is extremely fast -

385
00:33:07,520 --> 00:33:09,320
much faster than ever recorded -

386
00:33:09,320 --> 00:33:11,600
so we need to help them
a little bit in the lab.

387
00:33:11,600 --> 00:33:15,200
We need to speed up those
natural processes of evolution.

388
00:33:17,520 --> 00:33:22,600
Van Oppen's aim is to use selective
breeding to produce strains of coral

389
00:33:22,600 --> 00:33:26,400
that are able to withstand the
worst effects of climate change...

390
00:33:28,760 --> 00:33:33,960
..and to use them to bring life back
to worst-affected part of the reef.

391
00:33:36,280 --> 00:33:38,280
Maybe in five years or so,

392
00:33:38,280 --> 00:33:41,360
we will be allowed
to place those corals

393
00:33:41,360 --> 00:33:44,520
onto a real reef, a disturbed reef -

394
00:33:44,520 --> 00:33:47,200
and test it and these
selectively-bred corals

395
00:33:47,200 --> 00:33:49,760
will be able to restore
that reef faster.

396
00:33:51,080 --> 00:33:54,360
And you have to realise, this is
really a last resort option.

397
00:33:54,360 --> 00:33:57,880
We wouldn't want to do that if
the reef is able to restore itself.

398
00:34:03,400 --> 00:34:07,240
But is there a chance that the reef,
damaged by our activities,

399
00:34:07,240 --> 00:34:09,880
could restore itself
without our help?

400
00:34:12,480 --> 00:34:14,800
Well, we now think that
there may be clues

401
00:34:14,800 --> 00:34:17,800
in the reef's most distant
and mysterious regions.

402
00:34:25,120 --> 00:34:27,760
There are still parts of
the Great Barrier Reef

403
00:34:27,760 --> 00:34:30,400
that are virtually unexplored.

404
00:34:30,400 --> 00:34:34,680
But today, we have got remarkable
new underwater vessels,

405
00:34:34,680 --> 00:34:37,600
like this submersible,
that can take us to places

406
00:34:37,600 --> 00:34:42,200
where no unprotected human being
could possibly go.

407
00:34:42,200 --> 00:34:46,280
What they will find down there,
nobody knows.

408
00:34:46,280 --> 00:34:48,480
But I'm lucky enough
to be one of those

409
00:34:48,480 --> 00:34:50,920
who's about to go down to find out.

410
00:34:53,560 --> 00:34:55,400
At the outer edge of the reef,

411
00:34:55,400 --> 00:35:00,560
the continental shelf plunges down
over 2,000 metres to the seafloor.

412
00:35:05,120 --> 00:35:08,400
The Alucia has brought us
over the edge of the drop-off,

413
00:35:08,400 --> 00:35:11,240
90 miles out into the Coral Sea...

414
00:35:14,560 --> 00:35:16,720
..out to Osprey Reef.

415
00:35:19,200 --> 00:35:23,120
Here at Osprey, this sheer
vertical drop of the seafloor

416
00:35:23,120 --> 00:35:26,080
enables us to see corals
at a variety of depths.

417
00:35:27,800 --> 00:35:30,560
Between 100 and 150 metres down,

418
00:35:30,560 --> 00:35:32,960
daylight is reduced to a glimmer.

419
00:35:32,960 --> 00:35:36,200
This is the mesophotic zone.

420
00:35:36,200 --> 00:35:39,480
Here, a mysterious community
of corals is thriving,

421
00:35:39,480 --> 00:35:42,520
despite the damage being done
to the reef above.

422
00:35:42,520 --> 00:35:45,440
The Great Barrier Reef,
it's a marvel beyond marvels.

423
00:35:45,440 --> 00:35:50,720
It's a million species living
in this symbiotic tangle,

424
00:35:50,720 --> 00:35:52,240
half of which we don't know.

425
00:35:52,240 --> 00:35:54,920
I mean, when you get
to mesophotic depths,

426
00:35:54,920 --> 00:35:57,280
we know very few of
the species down there.

427
00:35:57,280 --> 00:36:00,800
It literally is one of the
last frontiers of biology,

428
00:36:00,800 --> 00:36:02,240
to understand this system.

429
00:36:05,680 --> 00:36:08,920
Scientists are now beginning
to wonder if these corals

430
00:36:08,920 --> 00:36:13,120
might have the potential to restore
the damaged parts of the reef.

431
00:36:14,400 --> 00:36:16,640
RADIO: '..Down about 100 metres...'

432
00:36:22,560 --> 00:36:24,600
Our state-of-the-art submersible

433
00:36:24,600 --> 00:36:28,440
is going to take me to see
these deep corals for myself

434
00:36:28,440 --> 00:36:30,280
and even bring back a sample.

435
00:36:35,440 --> 00:36:37,520
Nadir in position.

436
00:36:37,520 --> 00:36:39,600
Are we clear to vent?

437
00:36:39,600 --> 00:36:42,640
You are clear to vent,
clear to vent.

438
00:36:42,640 --> 00:36:44,080
Roger. Venting now.

439
00:36:56,600 --> 00:36:59,920
We are descending
into the twilight zone.

440
00:37:07,000 --> 00:37:09,680
As we drop down the face of the reef,

441
00:37:09,680 --> 00:37:11,800
the light begins to dim.

442
00:37:20,200 --> 00:37:22,440
At about 100 metres,

443
00:37:22,440 --> 00:37:25,680
we enter the mesophotic zone.

444
00:37:25,680 --> 00:37:28,720
"Mesophotic" literally means
"middle light".

445
00:37:31,200 --> 00:37:34,560
The corals here are beginning
to look very different.

446
00:37:36,960 --> 00:37:39,520
Despite the apparent
lack of light down here,

447
00:37:39,520 --> 00:37:43,200
there's still enough for some
corals to photosynthesise,

448
00:37:43,200 --> 00:37:46,120
just like their relations
closer to the surface.

449
00:37:46,120 --> 00:37:49,960
And to do that, they've formed
these flat, broad plates

450
00:37:49,960 --> 00:37:52,320
to collect what
little light there is.

451
00:37:57,000 --> 00:38:01,640
Mesophotic corals lie mostly out
of reach of cyclones and bleaching.

452
00:38:04,040 --> 00:38:07,200
So, one of the big questions
facing scientists is,

453
00:38:07,200 --> 00:38:12,280
could these deeper corals naturally
repopulate the damaged reefs above?

454
00:38:23,600 --> 00:38:27,040
We've now passed beyond
the mesophotic zone.

455
00:38:30,280 --> 00:38:32,840
The light begins to
disappear completely

456
00:38:32,840 --> 00:38:35,400
and the reef changes again.

457
00:38:47,240 --> 00:38:50,160
Most of the light that
filters down from above

458
00:38:50,160 --> 00:38:53,040
comes from the blue end
of the spectrum,

459
00:38:53,040 --> 00:38:57,560
so the rock surface
ahead of me looks very dull.

460
00:38:57,560 --> 00:39:00,680
But turn on the lights
and it looks very different.

461
00:39:24,920 --> 00:39:26,960
Despite their remoteness,

462
00:39:26,960 --> 00:39:29,840
these strange relatives
of reef-building corals

463
00:39:29,840 --> 00:39:32,200
are still part of
the great reef system.

464
00:39:34,320 --> 00:39:38,080
To understand how they're connected,
we need to study them closely.

465
00:39:40,280 --> 00:39:44,040
So, this seems an excellent place
to collect a sample.

466
00:39:46,480 --> 00:39:50,920
But manoeuvring our eight-tonne
submersible close to the rock face

467
00:39:50,920 --> 00:39:52,560
is a delicate operation.

468
00:40:11,560 --> 00:40:13,280
Oh, that's great.

469
00:40:22,000 --> 00:40:25,120
The chances are that this
could well be a species

470
00:40:25,120 --> 00:40:27,080
that no-one has ever seen before.

471
00:40:30,560 --> 00:40:33,400
But things don't go quite to plan.

472
00:40:36,200 --> 00:40:38,880
Oh, no! We're going to have
to go and fetch that.

473
00:40:51,920 --> 00:40:53,240
There it is.

474
00:41:07,280 --> 00:41:08,680
Oh, terrific!

475
00:41:13,360 --> 00:41:14,880
Success!

476
00:41:24,600 --> 00:41:27,720
As we descend past
the 200 metre mark,

477
00:41:27,720 --> 00:41:31,480
the coral finally begins
to disappear altogether.

478
00:41:36,760 --> 00:41:38,960
Surface, surface, Nadir.

479
00:41:38,960 --> 00:41:43,280
My depth now, 300 metres. Over.

480
00:41:44,680 --> 00:41:49,360
At this depth, the pressure bearing
down on the submersible's sphere

481
00:41:49,360 --> 00:41:52,200
is more than 30 times
that at the surface.

482
00:41:54,400 --> 00:41:58,480
That's an incredible
450 pounds per square inch.

483
00:42:02,800 --> 00:42:05,800
Here, there's a sediment that is
drifting down from above,

484
00:42:05,800 --> 00:42:08,440
cloaking the surface of the reef.

485
00:42:08,440 --> 00:42:11,080
That means it's very difficult
for any organism

486
00:42:11,080 --> 00:42:15,520
to get a hold of the rock, because
it's continually being swept down.

487
00:42:15,520 --> 00:42:21,040
The sediment itself is the
result of the erosion of the
coral skeletons from high above,

488
00:42:21,040 --> 00:42:24,400
but also from the remains of coral

489
00:42:24,400 --> 00:42:27,640
that parrot fish have
munched and excreted

490
00:42:27,640 --> 00:42:30,000
and it's slowly drifting down here.

491
00:42:30,000 --> 00:42:33,360
So, this is so deep,
it's almost barren.

492
00:42:43,600 --> 00:42:45,280
But not quite.

493
00:42:47,880 --> 00:42:50,680
At almost the deepest point
of our dive,

494
00:42:50,680 --> 00:42:52,520
something pays us a visit.

495
00:42:56,000 --> 00:42:59,040
There's a fish to your right,
David. On your shoulder.

496
00:42:59,040 --> 00:43:00,440
Look at this!

497
00:43:06,160 --> 00:43:08,720
It's a deep-water grouper.

498
00:43:08,720 --> 00:43:12,840
No-one has ever seen them up close
like this, at this depth.

499
00:43:20,400 --> 00:43:23,920
'It appears to find the sub
and its occupants fascinating.'

500
00:43:26,200 --> 00:43:29,520
And he's big, this boy. He must be...

501
00:43:31,800 --> 00:43:34,800
..four, five feet long -
a couple of metres, almost.

502
00:43:37,640 --> 00:43:38,840
Hello.

503
00:43:38,840 --> 00:43:40,240
Oh, gosh!

504
00:43:44,960 --> 00:43:48,320
And why he is down here,
what he's looking for - who knows?

505
00:43:56,120 --> 00:43:57,320
He's going up.

506
00:43:59,160 --> 00:44:00,400
So are we.

507
00:44:10,720 --> 00:44:15,400
As we ascend, light and colour
returns to the reef around us.

508
00:44:57,560 --> 00:45:01,560
'Our on-board reef scientist,
Professor Justin Marshall,

509
00:45:01,560 --> 00:45:05,000
'is on hand to retrieve the sample
we gathered in the darkness.'

510
00:45:05,000 --> 00:45:07,680
What do you reckon?
Well, it's fantastic.

511
00:45:07,680 --> 00:45:11,520
This is one of the deepest
samples ever from Osprey Reef.

512
00:45:11,520 --> 00:45:14,000
It's wonderful. Will it survive?
Will it still live?

513
00:45:14,000 --> 00:45:16,440
It will still live
and we'll take samples back

514
00:45:16,440 --> 00:45:19,800
to the University of Queensland
and work on it there. Great.

515
00:45:21,840 --> 00:45:25,000
In fact, they think this coral
has never been reported

516
00:45:25,000 --> 00:45:28,320
in this part of the world before
and may be new to science.

517
00:45:32,960 --> 00:45:35,680
We are a long way off
from having a solution

518
00:45:35,680 --> 00:45:38,880
to the threats which now face
the Great Barrier Reef.

519
00:45:40,920 --> 00:45:42,960
But in these deep water samples

520
00:45:42,960 --> 00:45:45,800
and in the scientists'
experimental tanks,

521
00:45:45,800 --> 00:45:47,680
there is a small glimmer of hope.

522
00:45:50,280 --> 00:45:52,600
But time is not on our side -...

523
00:45:56,760 --> 00:46:00,400
..an opinion shared by many of the
scientists I've met along the way.

524
00:46:05,120 --> 00:46:07,520
Are you fearful for
the future of the reef?

525
00:46:07,520 --> 00:46:09,200
There will be change, for sure.

526
00:46:09,200 --> 00:46:14,040
I mean, we're seeing change within
our own human lives' timescales now.

527
00:46:14,040 --> 00:46:15,800
And what's your prediction about

528
00:46:15,800 --> 00:46:18,920
what it's going to look like
in another hundred years?

529
00:46:18,920 --> 00:46:20,960
The sea levels will be higher.

530
00:46:20,960 --> 00:46:23,760
We want to know - as
a scientist, we want to know

531
00:46:23,760 --> 00:46:26,000
how the Great Barrier Reef
will respond.

532
00:46:26,000 --> 00:46:29,840
Whether it has
the resilience to bounce back

533
00:46:29,840 --> 00:46:34,360
with the future changes to
the climate remains to be seen.

534
00:46:39,120 --> 00:46:40,640
Here on the Great Barrier Reef,

535
00:46:40,640 --> 00:46:44,280
we've lost about 50% of the coral
since the early 1980s.

536
00:46:46,480 --> 00:46:50,640
Coral provides a habitat
for over a million species.

537
00:46:50,640 --> 00:46:53,880
This is such a fundamental
part of our oceans

538
00:46:53,880 --> 00:46:56,680
and the fact that it's going
to disappear on our watch,

539
00:46:56,680 --> 00:46:57,920
it's incredible.

540
00:47:15,600 --> 00:47:19,280
When the Great Barrier Reef
starts to go seriously backwards,

541
00:47:19,280 --> 00:47:21,080
the next generation is going to say,

542
00:47:21,080 --> 00:47:24,920
"Why didn't you guys do something
about it when you had a chance?"

543
00:47:24,920 --> 00:47:26,960
And well may they ask that

544
00:47:26,960 --> 00:47:30,000
because we're not doing
what we should be doing

545
00:47:30,000 --> 00:47:32,040
and we're going to pay the price.

546
00:47:50,200 --> 00:47:53,600
The Great Barrier Reef
is in grave danger.

547
00:47:53,600 --> 00:47:56,800
The twin perils brought
by climate change

548
00:47:56,800 --> 00:48:01,280
and increase in the temperature of
the ocean and in its acidity

549
00:48:01,280 --> 00:48:04,360
threaten its very existence.

550
00:48:04,360 --> 00:48:07,600
If they continue to rise
at the present rate,

551
00:48:07,600 --> 00:48:11,080
the reefs will be gone
within decades.

552
00:48:11,080 --> 00:48:14,880
And that would be
a global catastrophe.

553
00:48:17,720 --> 00:48:21,640
About one quarter of the
species of fish in the world

554
00:48:21,640 --> 00:48:25,120
spend some part of their lives
in the reefs.

555
00:48:25,120 --> 00:48:28,720
If the reefs go,
the fish will also disappear.

556
00:48:29,920 --> 00:48:32,560
And that could affect the livelihood

557
00:48:32,560 --> 00:48:36,040
and diet of human
communities worldwide.

558
00:48:37,640 --> 00:48:41,720
But there's surely another reason
why we should protect the reefs.

559
00:48:41,720 --> 00:48:45,840
They are among this planet's
richest, most complex

560
00:48:45,840 --> 00:48:48,320
and most beautiful ecosystems.

561
00:49:05,080 --> 00:49:09,800
Do we really care so little about
the Earth on which we live

562
00:49:09,800 --> 00:49:13,800
that we don't wish to protect
one of its greatest wonders

563
00:49:13,800 --> 00:49:16,840
from the consequences
of our behaviour?

564
00:49:41,640 --> 00:49:44,360
For this series, the
production team were determined

565
00:49:44,360 --> 00:49:47,120
to show the Barrier Reef
in a new way,

566
00:49:47,120 --> 00:49:49,960
by filming in some of
its most remote areas...

567
00:49:52,440 --> 00:49:54,120
..and allowing me to meet

568
00:49:54,120 --> 00:49:57,200
some of its more unusual
and surprising inhabitants.

569
00:49:59,720 --> 00:50:02,960
'This took us out onto the top
of Heron Island's reef,

570
00:50:02,960 --> 00:50:05,080
'which is only exposed at low tide.

571
00:50:08,680 --> 00:50:11,520
'But we had to tread carefully,
accompanied by guides,

572
00:50:11,520 --> 00:50:14,720
'to ensure that we didn't
damage any of the coral.'

573
00:50:16,040 --> 00:50:18,200
Anybody who's coming on here,
it's weird at first,

574
00:50:18,200 --> 00:50:21,640
but just try and walk on the
dead coral - the concrete stuff.

575
00:50:21,640 --> 00:50:24,120
'We were there to film
an elusive creature

576
00:50:24,120 --> 00:50:27,760
'that feeds in this special habitat
when the tide is out -

577
00:50:27,760 --> 00:50:29,280
'the epaulette shark.'

578
00:50:30,600 --> 00:50:34,040
There's one with a tail -
the first one is there.

579
00:50:34,040 --> 00:50:36,680
Just gone. It's gone under there.

580
00:50:38,920 --> 00:50:43,880
'Professor Gillian Renshaw has been
studying these sharks for 20 years.'

581
00:50:43,880 --> 00:50:46,040
It's very hard to see
the epaulettes

582
00:50:46,040 --> 00:50:49,240
because they're cryptically
coloured and blend in very well

583
00:50:49,240 --> 00:50:52,920
with the fingers of coral that are
rising out of the reef platform.

584
00:50:54,360 --> 00:50:57,200
'It's a challenging location,
not least because

585
00:50:57,200 --> 00:51:00,040
'it's only accessible for
short periods of time.'

586
00:51:02,280 --> 00:51:04,520
We've got probably about 40 minutes

587
00:51:04,520 --> 00:51:06,640
to get all of the shots
that we need,

588
00:51:06,640 --> 00:51:10,000
so I shouldn't really be talking
to you, we should be getting this.

589
00:51:10,000 --> 00:51:14,240
OK, quiet please!
Camera's rolling. And action, David.

590
00:51:14,240 --> 00:51:17,520
The epaulette shark
remains on the reef,

591
00:51:17,520 --> 00:51:19,720
even when the tide goes out.

592
00:51:21,000 --> 00:51:23,000
Of course, with so little water,

593
00:51:23,000 --> 00:51:26,240
it doesn't get as much oxygen
as it requires normally, but...

594
00:51:28,200 --> 00:51:30,120
'Although my piece is done,

595
00:51:30,120 --> 00:51:33,360
'the team must now film the shark's
unique walking behaviour.'

596
00:51:33,360 --> 00:51:36,200
The water is literally pouring
in around the equipment

597
00:51:36,200 --> 00:51:37,840
and over our feet.

598
00:51:37,840 --> 00:51:40,480
We've got about 10 to 15 minutes
to get this sequence finished

599
00:51:40,480 --> 00:51:42,840
and get back in the boats
before we're literally cut off

600
00:51:42,840 --> 00:51:44,920
and we can't get back to the boats.

601
00:51:46,960 --> 00:51:49,400
'The tide creeps in around us.'

602
00:51:55,120 --> 00:51:57,320
He's walking beautifully, now.
Look at that.

603
00:51:59,520 --> 00:52:02,800
Let's try and get it
in the water a bit.

604
00:52:02,800 --> 00:52:05,680
Really nice performance
from the epaulette shark.

605
00:52:07,680 --> 00:52:10,320
'Now, it's a race against time
to get off the reef.'

606
00:52:11,600 --> 00:52:13,000
Are we ready for the boat, now?

607
00:52:13,000 --> 00:52:15,400
Geraldine, can we get
David on, please?

608
00:52:20,560 --> 00:52:22,920
Yeah, looked stunning.
Worth the stress.

609
00:52:24,720 --> 00:52:27,880
'This trip took us from
the very top of the reef

610
00:52:27,880 --> 00:52:29,920
'down almost to its bottom...

611
00:52:31,080 --> 00:52:33,880
'..for our most ambitious
sequence of the series -...

612
00:52:35,280 --> 00:52:37,760
'..to attempt
the deepest dive in this area

613
00:52:37,760 --> 00:52:41,400
'and collect a sample of the
mysterious coral that survives there.

614
00:52:42,920 --> 00:52:45,400
'And it's down to
cameraman Paul Williams

615
00:52:45,400 --> 00:52:47,600
'to film our mission
single-handedly.'

616
00:52:49,520 --> 00:52:51,360
I'm on my own down there.

617
00:52:51,360 --> 00:52:53,400
I've gone over it and over it
again in my mind,

618
00:52:53,400 --> 00:52:56,240
about what we're trying to do
and how we're going to do it,

619
00:52:56,240 --> 00:52:58,240
so I think I've got it locked in.

620
00:52:58,240 --> 00:53:00,280
I hope haven't forgotten anything.

621
00:53:00,280 --> 00:53:02,400
'It's something of
a squeeze in the sub,

622
00:53:02,400 --> 00:53:05,400
'with all of Paul's
filming equipment.'

623
00:53:05,400 --> 00:53:07,920
Do you mind if I just
give you that for a moment?

624
00:53:09,040 --> 00:53:11,840
'But our third crew member
is essential.

625
00:53:11,840 --> 00:53:14,080
'He's the pilot, Buck Taylor.'

626
00:53:18,360 --> 00:53:21,400
I'm sitting with a big
camera on my shoulder

627
00:53:21,400 --> 00:53:24,440
and two other cameras,
which were outside the sub,

628
00:53:24,440 --> 00:53:27,560
controlled by laptops
which were both on my lap.

629
00:53:31,360 --> 00:53:34,400
The sound kit was under Buck's feet.

630
00:53:34,400 --> 00:53:35,560
It was tight in there.

631
00:53:43,920 --> 00:53:45,280
David, do you mind?

632
00:53:45,280 --> 00:53:48,240
Would you get your towel and just
give that a little wipe there? Yup.

633
00:53:48,240 --> 00:53:50,080
Thank you, sir.

634
00:53:53,000 --> 00:53:55,160
'For the first part of the dive,

635
00:53:55,160 --> 00:53:57,760
'underwater cameramen
filmed the sub's descent.

636
00:53:59,040 --> 00:54:02,040
'But at about 60 metres,
they reached their limit.

637
00:54:04,280 --> 00:54:06,360
'It's only possible
to venture further

638
00:54:06,360 --> 00:54:08,720
'within the protection
of the submarine.

639
00:54:10,080 --> 00:54:13,440
'As we enter the mesophotic zone,
around 100 metres down,

640
00:54:13,440 --> 00:54:14,960
'we're on our own.

641
00:54:19,320 --> 00:54:21,840
'To get the best shots
of the reef beyond,

642
00:54:21,840 --> 00:54:24,800
'Paul requires all of
Buck's skill as a pilot.'

643
00:54:26,000 --> 00:54:28,760
Do you want to try
some other light options?

644
00:54:28,760 --> 00:54:31,240
What have you got?
I can give you that.

645
00:54:31,240 --> 00:54:35,040
Yeah, put the higher ones on,
take the lower ones off.

646
00:54:35,040 --> 00:54:39,240
How's that? Yes. Actually,
that looks better. Isn't it lovely?

647
00:54:39,240 --> 00:54:41,640
Probably full of nooks
and crannies. Yeah.

648
00:54:41,640 --> 00:54:43,400
Buck, the sub driver, was brilliant.

649
00:54:43,400 --> 00:54:45,320
He'd find a drift in the currents

650
00:54:45,320 --> 00:54:47,320
and then we'd just drift
across the coral.

651
00:54:47,320 --> 00:54:49,600
What's nice is,
I can actually see the wall.

652
00:54:49,600 --> 00:54:52,600
That's a very good angle for me.
Is it? Yeah.

653
00:54:52,600 --> 00:54:55,960
So, just let us drift
a tiny bit to starboard.

654
00:54:55,960 --> 00:54:57,920
And...action, David.

655
00:54:57,920 --> 00:55:03,480
This wall of rock ahead of me is
actually the flank of Osprey Reef -

656
00:55:03,480 --> 00:55:06,240
an oasis for life.

657
00:55:06,240 --> 00:55:08,880
'But we weren't down here
just to look.

658
00:55:08,880 --> 00:55:12,720
'We also wanted to collect samples
for deep reef scientists...

659
00:55:14,720 --> 00:55:17,640
'..and that proved
easier said than done.'

660
00:55:17,640 --> 00:55:20,680
Oh, no!
We have to go and fetch that.

661
00:55:20,680 --> 00:55:22,000
We'll take that on film.

662
00:55:24,400 --> 00:55:27,200
'As we descended beyond 250 metres,

663
00:55:27,200 --> 00:55:30,720
'we entered a landscape rarely
seen with the naked eye.

664
00:55:33,120 --> 00:55:36,360
'It was the perfect opportunity
simply to explore.'

665
00:55:37,720 --> 00:55:40,160
This is the first time
that manned submersibles

666
00:55:40,160 --> 00:55:41,800
have worked at this depth

667
00:55:41,800 --> 00:55:44,520
and it gives one the ability
to look and observe

668
00:55:44,520 --> 00:55:47,480
and just do curiosity-driven
research.

669
00:55:47,480 --> 00:55:49,320
It's fantastic.

670
00:55:49,320 --> 00:55:52,120
The visibility down here
spectacular, isn't it?

671
00:55:52,120 --> 00:55:54,400
It's absolutely pure, yeah.

672
00:55:54,400 --> 00:55:57,640
There were many times when I had to
take my eye away from the eyepiece

673
00:55:57,640 --> 00:56:00,480
because I just had to
look with my own eyes,

674
00:56:00,480 --> 00:56:03,200
so it goes into the brain properly

675
00:56:03,200 --> 00:56:04,760
in the right perspective.

676
00:56:06,560 --> 00:56:08,800
'Soon, we reached our target depth.'

677
00:56:11,840 --> 00:56:13,280
There it is. 300.

678
00:56:14,960 --> 00:56:20,480
Nobody before has ever been as deep
as this on the Great Barrier Reef.

679
00:56:20,480 --> 00:56:22,000
I like it.

680
00:56:22,000 --> 00:56:24,680
LAUGHTER

681
00:56:24,680 --> 00:56:27,400
So, it hasn't even come up
on here - 290 metres,

682
00:56:27,400 --> 00:56:30,360
but we've heard that they've
just reached 300 metres.

683
00:56:30,360 --> 00:56:33,960
Another thing to add to the things
that David's done on this planet.

684
00:56:33,960 --> 00:56:36,240
'The purpose of our
record-breaking trip

685
00:56:36,240 --> 00:56:40,120
'was to raise awareness
of the reef's fragility.

686
00:56:40,120 --> 00:56:43,360
'Fortunately, while production
continued on the series,

687
00:56:43,360 --> 00:56:46,160
'the dive caught
the attention of a president.'

688
00:56:47,360 --> 00:56:51,800
Mr President.
When I heard that you had gone down,

689
00:56:51,800 --> 00:56:54,480
you dove into
the Great Barrier Reef again...

690
00:56:56,120 --> 00:56:57,960
..60 years after the first time
you did it?

691
00:56:57,960 --> 00:56:59,600
Yes. That impressed me.

692
00:56:59,600 --> 00:57:02,040
Ah, but I was in a sub.

693
00:57:02,040 --> 00:57:04,640
I mean, I was in a very,
very remarkable research sub

694
00:57:04,640 --> 00:57:06,880
and we went down to over 300 metres.

695
00:57:06,880 --> 00:57:09,120
Oh, so you went really deep.

696
00:57:09,120 --> 00:57:11,040
And that was just mind-blowing.

697
00:57:12,280 --> 00:57:16,040
The deep dive proved
a truly memorable moment for me

698
00:57:16,040 --> 00:57:19,160
and allowed us the unique
opportunity of revealing

699
00:57:19,160 --> 00:57:22,640
a part of this great reef
that has never before been seen.