Blue Planet II 1x1

1. The oceans, seemingly limitless,

2. invoke in us a sense of awe and wonder and also sometimes fear.

3. They cover 70% of the surface of our planet,

4. and yet they are still the least explored.

5. Hidden beneath the waves right beneath my feet,

6. there are creatures beyond our imagination.

7. With revolutionary technology, we can enter new worlds...

8. and shine a light on behaviours

9. in ways that were impossible just a generation ago.

10. We've also recognised an uncomfortable fact.

11. The health of our oceans is under threat.

12. They're changing at a faster rate than ever before in human history.

13. Never has there been a more crucial time

14. to reveal what is going on beneath the surface of the seas.

15. In this first episode,

16. we will journey across the globe from the warm waters of the tropics

17. to the coldest around the poles.

18. To bring us a new understanding of live beneath the waves.

19. This is Blue Planet H.

20. The surface of the ocean conceals the many creatures that live beneath

21. but not all.

22. Bottlenose dolphins.

23. They're extremely intelligent.

24. And with this intelligence comes playfulness.

25. They surf.

26. And as far as we can tell, they do so for the sheer joy of it.

27. But to properly appreciate their true character,

28. you have to travel with them into their world.

29. A pod of bottlenose dolphins is visiting a coral reef in the Red Sea.

30. For the youngsters, there are things to be learned here.

31. The adults lead a calf to a particular bush-like coral

32. called a Gorgonian.

33. And here, the adults behave rather strangely.

34. They deliberately rub themselves through the fronds.

35. Their calf seems reluctant to do so.

36. By watching his elders,

37. he may be realising that this is something he ought to do.

38. Gorgonia fronds, in fact, are covered with a mucous

39. that can have anti-inflammatory and antimicrobial properties.

40. So maybe the adult dolphins are doing this

41. to protect themselves from infection.

42. The dolphins' intimate knowledge of the reef

43. is spurring us to search for new medicines here, too.

44. Tropical coral reefs

45. occupy only a tenth of one percent of the ocean floor.

46. But their shallow warm waters and stable year round conditions,

47. support some of the most crowded and varied communities

48. to be found anywhere in the oceans.

49. And there are new discoveries to be made on every one of them.

50. One creature on Australia's Great Barrier Reef

51. is challenging our understanding of fish intelligence.

52. A tusk fish.

53. And you can see why it gets its name.

54. He does something few would have believed a fish could do.

55. Every morning, he travels to the edge of the reef.

56. He's searching for something special to eat

57. amongst the coral and sand.

58. Here's one.

59. A small clam.

60. But how to crack it open and get to the meat?

61. He takes it all the way back

62. to his special kitchen.

63. A bowl-shaped coral

64. that has a particular bump on the inside that he always uses.

65. It's not easy if you have no hands.

66. Whoops.

67. There he goes again.

68. But he's got great determination

69. and surprising accuracy.

70. At last.

71. So here is a fish that uses tools.

72. Some fish are much cleverer than you might suppose.

73. The density of the animals on tropical reefs

74. makes competition inevitable and extreme.

75. Not only for those that lived within the reef,

76. but for the birds that fly above them.

77. During the dry season,

78. over half a million terns

79. crowd onto this remote atoll in the Indian Ocean.

80. Their chicks are still in their dark, juvenile plumage.

81. They vary in age.

82. Whilst the more advanced chicks take to the air,

83. others aren't quite ready yet.

84. Those just starting to learn to fly

85. use the shallow lagoon that occupies the centre of the atoll

86. as their training ground.

87. It's difficult for some of them to stay aloft for long.

88. Giant trevallies.

89. Usually, they're solitary hunters,

90. but about 50 of them have come here from neighbouring reefs

91. attracted by this abundance of potential prey.

92. The fledglings stay out of the water if they can,

93. they even drink on the wing.

94. If the trevally are to catch one now,

95. they have to up their game.

96. So there is a fish here that amazingly

97. has a brain capable of calculating the airspeed,

98. altitude and trajectory of a bird.

99. The time comes when every fledgling has to take to the air

100. and collect food for itself.

101. Their parents lead them to the training grounds.

102. If they're to survive,

103. they must learn quickly.

104. After a month of practising over the lagoon,

105. the youngsters start to leave

106. and take their chances out over the open sea.

107. The oceans hold 97% of all the water in the world.

108. As the sun warms their surface, water evaporates.

109. The vapour rises into the sky

110. until it cools and condenses into towering clouds.

111. And they generate huge storms.

112. The spin of the earth deflects these storms

113. north and south into cooler latitudes.

114. As they travel across the sea,

115. storm-driven winds create huge swells.

116. When the swells reach shallower waters,

117. they rise into gigantic waves.

118. In its lifetime, a large storm can release energy

119. that is the equivalent of 70, 000 nuclear bombs.

120. These are the seasonal seas.

121. And when they warm in spring,

122. they can suddenly explode with life.

123. Mobula rays have gathered in Mexico's Sea of Cortez

124. in vast numbers.

125. Why do they leap?

126. Is it to tell others that they're here?

127. No one knows.

128. They feed mostly at night

129. for that is when vast swarms of plankton rise from the depths.

130. The disturbance in the water stimulates many of the planktonic creatures

131. to luminesce.

132. Only now do we have the technology to record their faint glow.

133. The feasting rays swim through them

134. creating an extraordinary ballet of life and death.

135. The richness of these waters is based on microscopic plants,

136. Phytoplankton,

137. which bloom on such a massive scale they benefit us all.

138. They, together with seaweeds and sea grasses,

139. produce as much oxygen

140. as all the forests and grassy plains on land.

141. Every spring off New Zealand,

142. the seasonal bounty draws in rare visitors.

143. False killer whales.

144. They're relatives of the orca,

145. six metres long and weighing over a tonne.

146. They appear to be searching for dolphins.

147. And there are many in these coastal waters.

148. Here, bottlenose dolphins stick together

149. constantly chattering with whistles and clicks.

150. Such a din carries for miles underwater.

151. The false killers have detected them.

152. Travelling at ten knots, the killers quickly close in on them.

153. But then, something truly extraordinary happens.

154. The dolphins turn

155. as if to greet their pursuers.

156. They seem to change their course.

157. Could it be that they're attempting to communicate?

158. Scientists studying this annual encounter,

159. now think that individuals may recognise one another.

160. Almost unbelievably, it seems that these different species

161. appear to be old friends.

162. Together they're gathering as one unified army

163. up to a thousand strong.

164. This formidable hunting party now harvests the riches

165. that come with New Zealand's summer.

166. All across the higher latitudes,

167. seasonal seas flourish under the summer sun.

168. Here in Alaska, sea otters lounge in the canopy

169. of great submarine forests.

170. Giant kelp, the biggest seaweed of all is home to all kinds of life.

171. On the forest floor, spiny sea urchins munch through the kelp.

172. Elsewhere there are continuously hungry sea cucumbers

173. And in the tangled undergrowth,

174. wonderfully camouflaged sea dragons.

175. In the underwater forests of northern Japan,

176. the residents of this sunken wreck

177. are waiting for the summer temperatures to reach 16 degrees Celsius.

178. That for some is the time for mating.

179. A kind of giant wrasse called a Kobudai.

180. This is a male.

181. And in female terms, he's particularly handsome.

182. He's a metre long and weighs 15 kilos.

183. Much larger than the diminutive female,

184. and he is ready to breed.

185. He attempts to mate with her

186. and with any of the dozen or so females that live in his territory,

187. whenever he gets the chance.

188. But females from around ten years old

189. take little notice of his advances.

190. This is because when any large female reaches a critical body size,

191. she can begin a dramatic transformation.

192. Over just a few months,

193. particular enzymes inside her body cease to work,

194. and male hormones start to circulate.

195. As time passes,

196. her head expands

197. and her chin gets longer.

198. A she has changed into a he.

199. And with this comes a change in temperament.

200. The old male who rules all the females here

201. is challenged to a face off.

202. The more bulbous the head,

203. the more it intimidates an opponent.

204. The territory has a new ruler.

205. Only the largest females transform themselves in this way.

206. But the change enables them to have more mates,

207. so they will have many more offspring carrying their genes.

208. But a new male can't afford to be complacent.

209. Inside the body of every Kobudai female,

210. there is a new male in waiting.

211. The closer we travel towards the poles, the colder the seas become.

212. Icebergs appear.

213. Huge slabs that have broken away

214. from glaciers that are sliding into the sea.

215. And then the surface starts to freeze.

216. While the lights of the aurora play above,

217. even in the depths of midwinter,

218. there are a few places well north of the Arctic circle

219. that are still open.

220. The fjords of northern Norway remain ice free

221. because a giant current, the Gulf Stream,

222. flows up here from the south

223. bringing warmth all the way from the Caribbean.

224. And every winter,

225. billions of herring come here for shelter.

226. And following them...

227. Orca.

228. There are up to a thousand of them.

229. It's possibly the greatest gathering of orca on the planet.

230. The herring maybe plentiful but in these winding fjords

231. they're not always easy to track down.

232. These particular orca, however,

233. are fish hunting specialists.

234. They work as a team,

235. coordinating their approach by calling loudly to one another.

236. They herd the herring into tighter and tighter shoals.

237. They swim below them,

238. trapping them against the surface of the sea.

239. And now the orca deploy their special weapon.

240. They beat their tails with such force,

241. that the shock waves stun the herring.

242. And then the senseless victims are easily collected.

243. But all this underwater noise attracts others.

244. Humpback whales.

245. They move in on the action.

246. They approach the shoal from beneath and then lunge upwards,

247. gathering up to a hundred kilos of herring in a single mouthful.

248. The humpbacks are comparative newcomers.

249. They only started coming here within the last decade.

250. But these polars seas are so rich

251. that there appears to be enough food for everyone.

252. Nonetheless, few if any of these riches

253. would be here were it not for the Gulf Stream.

254. Ocean currents, in fact, are crucial to the well being of our planet.

255. They distribute the sun's heat towards the poles

256. all the way from the equator,

257. maintaining a climate favourable for life almost everywhere.

258. From creating the weather to producing oxygen,

259. the seas keep our world healthy.

260. But there are now worrying signs

261. that conditions in the oceans

262. that have remained relatively stable for millennia

263. are changing radically.

264. Nowhere is this more evident than in the Arctic.

265. Here in the past 30 years,

266. the extent of the ice in summer has been reduced by 40%.

267. This sudden warming,

268. most likely a consequence of human activity,

269. is having a profound impact on its wildlife.

270. Walruses are among those that are seriously affected.

271. Every adult female needs to find a safe place

272. where her 80-kilo pup can rest.

273. The sea ice is retreating

274. from much of the walrus' traditional range,

275. so they now have to haul out on dry land.

276. But a herd of hundreds of quarrelsome mothers,

277. some weighing almost a tonne, is not an ideal nursery.

278. Walruses on land stick together for good reason.

279. Polar bears.

280. A full grown male walrus is gigantic,

281. too big for even a polar bear to tackle.

282. So the bear is looking for a walrus baby.

283. The scent of the bear spreads alarm through the colony.

284. The walruses retreat into the sea.

285. The bear knows it won't be able to catch them there.

286. But she too has young ones to feed.

287. What is a mother to do?

288. A mother walrus still needs to find a place

289. where her young can rest.

290. A melting iceberg might do,

291. but she is not the first to find this one.

292. Suitable places are already taken.

293. Other mothers don't want to share.

294. They, too, need a patch of ice where they can protect their young.

295. A desperate mother has no choice but to barge her way in.

296. So this time everyone loses.

297. Finding the right place on these melting shores

298. gets harder and harder.

299. Solving these problems together helps create a bond so strong

300. that the mother will stay in contact with her young for the rest of her life.

301. But who knows now what their future will be.

302. As we understand more about the complexity

303. of the lives of sea creatures,

304. so we begin to appreciate the fragility of their home.

305. Our blue planet.

306. Next time.

307. The deep.

308. A world richer than we ever though possible,

309. where creatures thrive,

310. in the most extreme conditions on Earth.