BBC.The.Green.Planet.2of5.Water.Worlds.1080p.HDTV.x265.AAC.MVGroup.org.eng Movie Subtitles

1 00:00:34,000 --> 00:00:38,440 Plants cover much of the land surface of our planet. 2 00:00:38,440 --> 00:00:42,880 But there is another extraordinary green world 3 00:00:42,880 --> 00:00:44,680 that is often hidden from us. 4 00:00:58,320 --> 00:01:01,880 It's one where plants have overcome huge challenges 5 00:01:01,880 --> 00:01:03,520 in order to survive. 6 00:01:11,880 --> 00:01:15,160 The world of fresh water. 7 00:01:28,840 --> 00:01:34,640 At first sight, a lake like this would seem to have everything 8 00:01:34,640 --> 00:01:37,920 that life needs in order to thrive. 9 00:01:37,920 --> 00:01:41,400 Clear, oxygen-rich water, 10 00:01:41,400 --> 00:01:44,600 plenty of dissolved nutrients and minerals 11 00:01:44,600 --> 00:01:47,160 and lots of sunlight. 12 00:01:47,160 --> 00:01:51,800 But, in fact, life in fresh water 13 00:01:51,800 --> 00:01:54,440 presents plants with huge problems. 14 00:01:57,720 --> 00:02:03,320 To succeed, plants have had to abandon many of the adaptations 15 00:02:03,320 --> 00:02:06,360 that served them so well on land 16 00:02:06,360 --> 00:02:10,440 and evolve something quite new and, doing that, 17 00:02:10,440 --> 00:02:15,440 they have created some of the most beautiful and bizarre 18 00:02:15,440 --> 00:02:18,080 and important habitats on Earth. 19 00:02:23,840 --> 00:02:27,480 There are few places where it's more difficult to make 20 00:02:27,480 --> 00:02:31,200 a permanent home than a freshwater torrent like this one. 21 00:02:51,480 --> 00:02:56,880 Violent currents drip across the riverbed, 22 00:02:56,880 --> 00:02:58,200 scouring it clean... 23 00:03:03,280 --> 00:03:07,680 ..whipping land plants from their margins 24 00:03:07,680 --> 00:03:08,920 and drowning them. 25 00:03:13,000 --> 00:03:16,800 How could any plant survive in a place like this? 26 00:03:28,920 --> 00:03:32,480 Yet, even here, some do manage to, 27 00:03:32,480 --> 00:03:35,200 quite literally, hold on. 28 00:03:39,800 --> 00:03:44,160 They can grasp the bare rock with remarkable strength. 29 00:03:50,360 --> 00:03:52,840 This ability allows plants to thrive 30 00:03:52,840 --> 00:03:55,680 in these otherwise hostile environments. 31 00:04:01,280 --> 00:04:05,560 This is the Cano Cristales river in Colombia. 32 00:04:21,280 --> 00:04:24,520 These plants are red Macarenia, 33 00:04:24,520 --> 00:04:28,600 sometimes called the Orchid of the Falls. 34 00:04:38,120 --> 00:04:41,560 They cling to the riverbed, not with their roots, 35 00:04:41,560 --> 00:04:46,040 but with their stems, glued to the rock surface by one 36 00:04:46,040 --> 00:04:48,160 of the most powerful adhesives in nature. 37 00:04:56,160 --> 00:04:58,280 The rock itself will break 38 00:04:58,280 --> 00:05:00,240 before these anchors lose their grip. 39 00:05:11,200 --> 00:05:15,680 These feathery filaments are their modified leaves, 40 00:05:15,680 --> 00:05:18,600 and they do what roots normally do - 41 00:05:18,600 --> 00:05:21,440 gather the minerals and nutrients they need 42 00:05:21,440 --> 00:05:23,040 that are dissolved in the water. 43 00:05:29,320 --> 00:05:33,360 With such spectacular colours, it's hardly surprising 44 00:05:33,360 --> 00:05:37,000 that the Cano Cristales is sometimes called 45 00:05:37,000 --> 00:05:40,160 the most beautiful river on Earth. 46 00:05:45,960 --> 00:05:49,960 But being rooted to the spot is not always the best strategy 47 00:05:49,960 --> 00:05:51,960 for living in a water world. 48 00:05:55,280 --> 00:05:58,560 This is a water lettuce, 49 00:05:58,560 --> 00:06:01,640 and it has some remarkable adaptations. 50 00:06:03,400 --> 00:06:06,840 Its roots hang free, 51 00:06:06,840 --> 00:06:09,880 so it's not anchored to the ground, 52 00:06:09,880 --> 00:06:13,360 and its leaves are thick and spongy 53 00:06:13,360 --> 00:06:16,120 and covered in fine hairs. 54 00:06:16,120 --> 00:06:19,240 So the plant itself is more or less unsinkable. 55 00:06:27,920 --> 00:06:32,000 This combination of characteristics enable the water lettuce 56 00:06:32,000 --> 00:06:36,240 to do something that almost no land plant can do. 57 00:06:36,240 --> 00:06:37,720 It can travel. 58 00:06:41,600 --> 00:06:45,800 It is an ability that becomes invaluable when, 59 00:06:45,800 --> 00:06:49,680 during the wet season, flooded rivers become great highways, 60 00:06:49,680 --> 00:06:52,720 as they do here in South America. 61 00:06:58,080 --> 00:07:02,080 This is the largest inland water world on Earth. 62 00:07:02,080 --> 00:07:03,520 The Pantanal. 63 00:07:04,960 --> 00:07:09,320 For a few months every year, it provides water plants 64 00:07:09,320 --> 00:07:12,040 with ideal conditions, 65 00:07:12,040 --> 00:07:16,760 but, all too soon, it becomes a battleground. 66 00:07:25,640 --> 00:07:29,360 Plants are racing to claim their space on the surface. 67 00:07:31,400 --> 00:07:35,840 The water lettuce rapidly expands its network of hanging roots 68 00:07:35,840 --> 00:07:38,280 so that it starts absorbing nutrients 69 00:07:38,280 --> 00:07:40,720 before other competitors arrive. 70 00:07:57,840 --> 00:08:00,240 Water hyacinth appears. 71 00:08:03,480 --> 00:08:08,160 Its leaves are carried on stalks filled with air 72 00:08:08,160 --> 00:08:11,160 that also make it virtually unsinkable. 73 00:08:16,440 --> 00:08:19,200 The race for space intensifies. 74 00:08:21,920 --> 00:08:25,680 A new competitor arrives, Ludwigia. 75 00:08:25,680 --> 00:08:29,400 It spreads by developing a chain of tiny rafts. 76 00:08:31,320 --> 00:08:34,520 And jostles for space with the densely packed leaves 77 00:08:34,520 --> 00:08:36,280 of mosaic plants. 78 00:08:43,440 --> 00:08:47,480 All are racing to claim as much sunlight as possible. 79 00:08:57,720 --> 00:09:01,280 They flower quickly before the floodwaters recede. 80 00:09:12,920 --> 00:09:16,520 And these surface dwellers also have competitors. 81 00:09:19,120 --> 00:09:22,240 Including one that has been waiting in the depths 82 00:09:22,240 --> 00:09:23,600 and is now stirring. 83 00:09:35,080 --> 00:09:37,200 It's a monster. 84 00:10:05,200 --> 00:10:07,160 It's well armed. 85 00:10:22,360 --> 00:10:27,040 It clears space for itself 86 00:10:27,040 --> 00:10:28,880 by wielding one of its buds. 87 00:10:30,680 --> 00:10:32,160 Like a club. 88 00:10:38,240 --> 00:10:42,000 And now it dominates the surface. 89 00:11:01,200 --> 00:11:04,880 This is a leaf of the giant water lily. 90 00:11:25,960 --> 00:11:29,800 It expands by over 20 centimetres a day 91 00:11:29,800 --> 00:11:31,520 and eventually measures 92 00:11:31,520 --> 00:11:33,200 more than two metres across. 93 00:11:38,560 --> 00:11:43,800 Its immense leaves are supported by a network of air-filled struts 94 00:11:43,800 --> 00:11:47,280 and protected by spines two centimetres long. 95 00:11:52,080 --> 00:11:56,240 The leaves float high in the water and their surfaces are dotted 96 00:11:56,240 --> 00:12:01,080 with tiny holes, drains, that help them ensure that rainwater 97 00:12:01,080 --> 00:12:03,480 doesn't accumulate and sink them. 98 00:12:17,640 --> 00:12:22,400 Nutrients from the fertile mud below are carried up by tubes 99 00:12:22,400 --> 00:12:26,080 in its stem to fuel the leaf's expansion. 100 00:12:34,040 --> 00:12:37,520 Over the next few months, the lily will produce 101 00:12:37,520 --> 00:12:40,560 some 40 or so of these gigantic leaves. 102 00:12:50,480 --> 00:12:55,680 And as each one reaches the surface and expands, more and more light 103 00:12:55,680 --> 00:12:59,400 is taken from those plants that are trying to grow beneath. 104 00:13:12,280 --> 00:13:15,120 Competitors are pushed aside. 105 00:13:38,800 --> 00:13:41,600 Some are crushed, 106 00:13:41,600 --> 00:13:43,160 or skewered. 107 00:14:20,640 --> 00:14:24,640 Eventually, its immense leaves press their margins 108 00:14:24,640 --> 00:14:26,880 against one another, 109 00:14:26,880 --> 00:14:30,600 totally cutting off the light from the plants beneath them. 110 00:14:33,640 --> 00:14:36,680 The battle is over. 111 00:14:36,680 --> 00:14:39,200 And victory is total. 112 00:14:58,680 --> 00:15:02,480 The frozen water world of Lake Akan in northern Japan. 113 00:15:06,960 --> 00:15:11,040 Home to one of the strangest and most primitive of plants. 114 00:15:14,520 --> 00:15:20,240 It's an alga, like those that appear so mysteriously in our ponds. 115 00:15:23,840 --> 00:15:27,080 But this one is truly extraordinary. 116 00:15:33,400 --> 00:15:38,160 Each spring, the melting ice releases soft, velvety balls 117 00:15:38,160 --> 00:15:43,120 of interwoven threads called Marimos. 118 00:15:46,760 --> 00:15:48,840 This one is small. 119 00:15:48,840 --> 00:15:50,560 No bigger than a walnut. 120 00:15:52,200 --> 00:15:54,480 But there are lots of them here. 121 00:16:00,440 --> 00:16:04,640 They attract the attention of visiting whooper swans. 122 00:16:33,120 --> 00:16:38,120 But there is one way for the Marimo to escape from the danger, 123 00:16:38,120 --> 00:16:40,200 and it depends on a change in the weather. 124 00:16:45,120 --> 00:16:49,960 Fortunately, in the spring, winds sweep across the lake... 125 00:16:52,120 --> 00:16:57,440 ..creating currents that carry some of the Marimos beyond the reach 126 00:16:57,440 --> 00:16:59,080 of hungry swans....