1 00:00:06,306 --> 00:00:07,830 The human mind 2 00:00:07,974 --> 00:00:12,843 has always had a fascination with worlds beyond our own 3 00:00:12,979 --> 00:00:15,641 Following the stars across the seas, 4 00:00:15,782 --> 00:00:17,147 early explorers 5 00:00:17,283 --> 00:00:22,277 imagined that they might meet weird creatures in undiscovered lands. 6 00:00:31,531 --> 00:00:34,864 They never guessed that under their keels, 7 00:00:35,001 --> 00:00:38,198 drifting in the same currents that carried their ships, 8 00:00:38,338 --> 00:00:42,832 were life forms far stranger than anything they could imagine. 9 00:00:46,946 --> 00:00:50,905 It's a world where the forces of pressure and darkness 10 00:00:51,051 --> 00:00:55,681 have given rise to creatures as different as on another planet. 11 00:01:10,970 --> 00:01:15,202 Their whole existence is shaped by the great ocean currents, 12 00:01:15,341 --> 00:01:17,309 which sweep them endlessly 13 00:01:17,444 --> 00:01:21,210 around the biggest living space in the solar system. 14 00:02:19,239 --> 00:02:22,436 At the edge of this alien world, here in Florida, 15 00:02:22,575 --> 00:02:26,011 one ocean drifter comes from the beach itself. 16 00:02:39,159 --> 00:02:41,184 It can take these hatchlings three days 17 00:02:41,327 --> 00:02:44,956 to claw their way up from nests buried two feet deep. 18 00:02:51,304 --> 00:02:53,568 They may look like land animals now, 19 00:02:53,706 --> 00:02:56,800 but sea turtles have evolved for 80 million years 20 00:02:56,943 --> 00:02:59,741 to be riders of the ocean currents. 21 00:03:07,654 --> 00:03:11,146 These loggerhead turtles, no larger than a child's hand, 22 00:03:11,291 --> 00:03:16,126 are about to embark on a perilous 10-year journey around the ocean. 23 00:03:19,699 --> 00:03:21,530 As they head down the beach, 24 00:03:21,668 --> 00:03:24,136 they're already reading the earth's magnetic field 25 00:03:24,270 --> 00:03:26,465 with their internal compass. 26 00:03:29,876 --> 00:03:33,107 Only one hatchling in a thousand will survive to adulthood 27 00:03:33,246 --> 00:03:37,046 and ride the currents back to this beach to breed. 28 00:03:37,183 --> 00:03:41,279 It's among the most extraordinary odysseys in nature. 29 00:04:05,478 --> 00:04:09,414 This is the story of one loggerhead's journey into the unknown world 30 00:04:09,549 --> 00:04:11,483 of the ocean drifters. 31 00:04:24,264 --> 00:04:29,258 Like a windup toy, the hatchling swims relentlessly out into the ocean. 32 00:04:31,170 --> 00:04:34,003 The waves tell her which way to go 33 00:04:34,540 --> 00:04:39,102 away from shore and from predators stalking the shallow water. 34 00:04:48,688 --> 00:04:53,216 Danger causes her to tuck in her limbs disguising herself as floating debris. 35 00:05:05,371 --> 00:05:08,738 The shark doesn't see her and swims on 36 00:05:18,651 --> 00:05:21,449 As she heads toward the safety of deep water, 37 00:05:21,587 --> 00:05:25,455 the hatchling joins a rich tide of other marine creatures. 38 00:05:37,170 --> 00:05:41,004 Every rock and weed is home to a different species. 39 00:05:45,912 --> 00:05:50,110 Coastal waters are the fertile breeding ground for the oceans. 40 00:05:51,084 --> 00:05:55,885 Florida may produce five million loggerhead hatchlings each year. 41 00:05:57,090 --> 00:05:58,853 In some coastal species, 42 00:05:58,991 --> 00:06:03,223 500 million offspring may come from a single female. 43 00:06:09,235 --> 00:06:10,930 The eggs of this sea urchin 44 00:06:11,070 --> 00:06:14,130 and the smoky clouds of sperm from a nearby male 45 00:06:14,273 --> 00:06:18,903 swirl together in a fertility dance on the ocean floor. 46 00:06:35,228 --> 00:06:38,720 Huge quantities of eggs and larvae produced along the coastline 47 00:06:38,865 --> 00:06:41,732 will be drawn into the ocean currents. 48 00:06:41,868 --> 00:06:44,860 Most will become food for other marine creatures. 49 00:06:47,673 --> 00:06:49,538 Setting their offspring adrift 50 00:06:49,675 --> 00:06:52,473 might not sound like good parental care. 51 00:06:52,612 --> 00:06:57,174 But it's a valuable survival mechanism for many coastal species. 52 00:06:57,717 --> 00:06:59,446 It lets them populate new areas 53 00:06:59,585 --> 00:07:02,645 and encourages the exchange of genetic material. 54 00:07:26,379 --> 00:07:31,282 All through the night, instinct drives the loggerhead to push on. 55 00:07:33,619 --> 00:07:36,850 The outpouring of new life on the continental shelf below her 56 00:07:36,989 --> 00:07:39,423 is just as persistent. 57 00:07:45,131 --> 00:07:47,793 With the bellows like action of her pleopods, 58 00:07:47,934 --> 00:07:52,837 the spiny lobster sends 700,000 hatchlings seaward. 59 00:07:55,775 --> 00:07:58,300 It's a reproductive blizzard. 60 00:08:18,297 --> 00:08:21,596 The lobster's larvae have evolved a flattened shape; 61 00:08:21,734 --> 00:08:26,569 it suits them for the drifting life as ideally as a snowflake. 62 00:08:45,558 --> 00:08:50,518 After 36 hours of swimming, the hatchling is growing tired. 63 00:08:53,332 --> 00:08:56,460 In the clear water 30 miles off the Florida Coast, 64 00:08:56,602 --> 00:08:58,900 she reaches the edge of the Gulf Stream, 65 00:08:59,038 --> 00:09:03,236 and finds shelter in the drift lines of sargassum weed. 66 00:09:07,914 --> 00:09:12,044 This plant spends its whole life floating on the open sea, 67 00:09:12,184 --> 00:09:14,948 held up by small air bladders. 68 00:09:24,463 --> 00:09:29,833 The sargassum provides a haven in a vast, featureless world. 69 00:09:31,504 --> 00:09:34,632 All kinds of creatures find harbor here. 70 00:09:47,219 --> 00:09:49,449 For the first time in her life, 71 00:09:49,589 --> 00:09:51,989 the loggerhead can rest. 72 00:10:00,299 --> 00:10:02,893 But the stillness is an illusion. 73 00:10:03,035 --> 00:10:06,061 The winds have piled up the sargassum weed in drift lines 74 00:10:06,205 --> 00:10:09,936 along the edge of one of the most powerful currents in the world. 75 00:10:10,576 --> 00:10:14,034 Just beyond, the Gulf Stream hurtles by. 76 00:10:16,282 --> 00:10:19,115 Viewed from space, the Earth is alive 77 00:10:19,251 --> 00:10:22,414 with clouds caught up in the rhythm of the tradewinds. 78 00:10:22,555 --> 00:10:25,388 These winds and the rotation of the planet 79 00:10:25,524 --> 00:10:28,220 generate the great ocean currents. 80 00:10:28,361 --> 00:10:31,023 The loggerhead will be traveling for years 81 00:10:31,163 --> 00:10:35,725 in a circle of currents called the North Atlantic gyre. 82 00:10:35,868 --> 00:10:40,601 Her journey starts off Florida in the warm waters of the Gulf Stream, 83 00:10:40,740 --> 00:10:43,800 which will carry her north past Cape Cod. 84 00:10:47,079 --> 00:10:49,240 Satellite imagery is teaching us 85 00:10:49,382 --> 00:10:52,613 that the Gulf Stream is a wild living carousel, 86 00:10:52,752 --> 00:10:57,416 spinning off side currents, and stirring up a broth of marine life 87 00:11:10,202 --> 00:11:14,468 The edges of currents are the great way stations of the open sea. 88 00:11:14,607 --> 00:11:17,735 Plant and animal drifters are drawn into these fronts, 89 00:11:17,877 --> 00:11:21,278 one species making life possible for another. 90 00:11:24,483 --> 00:11:29,147 For a hungry animal, it's an oasis in an oceanic desert. 91 00:11:35,227 --> 00:11:38,719 The sargassum becomes a perch for goose barnacles. 92 00:11:38,864 --> 00:11:41,594 They glean food particles from the plankton, 93 00:11:41,734 --> 00:11:46,068 the rich soup of plants and animals, many of them microscopic. 94 00:11:57,783 --> 00:11:59,444 Even sluggish homebodies 95 00:11:59,585 --> 00:12:03,544 can be marvelously adapted for travel in the larval stage. 96 00:12:04,423 --> 00:12:09,486 The glorious creature drifting on wing-like lobes is a snail. 97 00:12:16,302 --> 00:12:19,669 Some snail larvae use tentacle like arms 98 00:12:19,805 --> 00:12:21,932 for feeding and to keep from sinking. 99 00:12:22,074 --> 00:12:25,043 Some may by able to remain in this stage from months 100 00:12:25,177 --> 00:12:27,805 until they drift to a suitable habitat 101 00:12:30,149 --> 00:12:33,585 Everything is kept lightweight for easier travel. 102 00:12:33,719 --> 00:12:38,918 Look closely and you can see the spiral of a transparent shell. 103 00:12:56,842 --> 00:12:59,572 These beautiful drifters move so gracefully, 104 00:12:59,712 --> 00:13:04,945 you forget that the Gulf Stream is hurrying them along at 100 miles a day 105 00:13:09,255 --> 00:13:11,723 Microscopic larvae spawned in Florida 106 00:13:11,857 --> 00:13:15,452 could eventually settle on the shores of Africa. 107 00:13:16,128 --> 00:13:20,360 And the next generation may ride the currents back. 108 00:13:47,793 --> 00:13:49,920 The ocean drifters have little to eat 109 00:13:50,062 --> 00:13:54,192 except each other which they do eagerly. 110 00:13:57,102 --> 00:14:00,401 So if the sargassum weed provides shelter, 111 00:14:00,472 --> 00:14:02,406 it also harbors death 112 00:14:02,541 --> 00:14:08,104 in an astounding diversity of forms, often wonderfully camouflaged. 113 00:14:19,491 --> 00:14:23,222 The sea horse has evolved a mild and plant-like demeanor. 114 00:14:23,362 --> 00:14:26,854 But it's still a predator and keenly watchful. 115 00:14:35,774 --> 00:14:39,301 It drops down to ambush its planktonic prey. 116 00:14:45,384 --> 00:14:47,409 Then loops itself back into the sargassum 117 00:14:47,553 --> 00:14:50,579 to avoid being ambushed itself. 118 00:14:52,825 --> 00:14:54,884 The entire food chain is caught up 119 00:14:55,027 --> 00:14:59,020 in this dangerous game of deception and self-defense. 120 00:15:01,166 --> 00:15:04,567 Small fern-like animals known as hydroids 121 00:15:04,703 --> 00:15:09,436 colonize the sargassum and feed on the most minute plankton. 122 00:15:10,910 --> 00:15:14,004 A sea slug grazes in turn on hydroids. 123 00:15:24,957 --> 00:15:28,688 The slug's camouflage doesn't fool a potential predator. 124 00:15:28,827 --> 00:15:33,662 But the sea slug has armed itself with chemical defenses from its prey. 125 00:15:38,904 --> 00:15:41,634 The file fish abandons the attack. 126 00:15:43,175 --> 00:15:48,374 But another creature's camouflage will soon bring the fish to a gory end 127 00:16:32,891 --> 00:16:35,621 The drifting weed may look innocuous. 128 00:16:36,161 --> 00:16:37,321 But look again. 129 00:16:44,870 --> 00:16:49,068 A fish hoping to harvest hydroids from this leafy growth 130 00:16:49,208 --> 00:16:52,735 would find itself staring into a malignant eye. 131 00:17:01,620 --> 00:17:05,215 Evolution has made the four-inch long sargassum fish 132 00:17:05,357 --> 00:17:08,656 the big bad wolf of this floating world. 133 00:17:08,794 --> 00:17:13,925 Its extraordinary camouflage doesn't just mimic the coloration of the plant 134 00:17:14,066 --> 00:17:16,534 The white spots also mimic the tube worms 135 00:17:16,668 --> 00:17:19,330 and hydroids that grow on sargassum. 136 00:17:24,476 --> 00:17:28,936 Its pectoral fins have evolved into prehensile fingers, 137 00:17:29,081 --> 00:17:31,777 the better to creep through the foliage. 138 00:17:37,389 --> 00:17:40,153 It will eat creatures almost its own size, 139 00:17:40,292 --> 00:17:45,491 and its victims thrash around in its gut momentarily before they die 140 00:17:53,238 --> 00:17:56,765 The loggerhead swims directly under this hidden peril. 141 00:18:02,548 --> 00:18:05,984 But the sargassum fish lets her pass by. 142 00:18:17,830 --> 00:18:21,027 Hungry dolphin fish won't be so particular. 143 00:18:21,867 --> 00:18:27,635 These big, fast-moving fish can devour all life on the weed lines. 144 00:18:32,978 --> 00:18:35,776 The turtle scramble for a hiding place 145 00:19:25,664 --> 00:19:29,532 Now the loggerhead pushes onto deeper water. 146 00:19:44,149 --> 00:19:46,481 Beyond the sargassum in the open sea, 147 00:19:46,618 --> 00:19:50,520 gelatinous drifters are the most abundant life form. 148 00:19:50,989 --> 00:19:54,857 They may be the loggerhead's main source of food for much of her journey 149 00:20:17,149 --> 00:20:21,586 A jellyfish like this may be more than 95 percent water. 150 00:20:21,720 --> 00:20:25,486 But the thin membrane of living tissue is still nutritious. 151 00:20:38,303 --> 00:20:40,396 We know almost nothing about how the turtle 152 00:20:40,539 --> 00:20:43,007 or any other animal survives here. 153 00:20:46,812 --> 00:20:50,839 We act as if this is our planet and we call it Earth. 154 00:20:50,983 --> 00:20:53,349 But the oceans are so large 155 00:20:53,485 --> 00:20:57,421 and so deep that they constitute more than 99 percent 156 00:20:57,556 --> 00:20:59,581 of the inhabitable world. 157 00:21:04,830 --> 00:21:06,695 Even for oceanographers, 158 00:21:06,832 --> 00:21:09,460 the open sea is an alien environment, 159 00:21:09,601 --> 00:21:13,560 tantalizing and yet largely unexplored 160 00:21:16,141 --> 00:21:19,599 Each creature in the currents has its own story to tell, 161 00:21:19,745 --> 00:21:24,114 its own extraordinary adaptations to life on the open sea. 162 00:21:30,756 --> 00:21:33,782 Humans venturing into these waters with scuba gear 163 00:21:33,925 --> 00:21:37,088 study only the upper layers of the ocean. 164 00:21:40,132 --> 00:21:43,693 They stay tethered to a rope, like astronauts walking in space. 165 00:21:43,835 --> 00:21:46,827 It's a 500 mile swim to shore. 166 00:21:50,842 --> 00:21:53,970 Richard Harbison and his colleague Larry Madin 167 00:21:54,112 --> 00:21:55,807 are among the few researchers studying 168 00:21:55,947 --> 00:21:59,906 how these ocean drifters behave in their own environment. 169 00:22:03,355 --> 00:22:06,882 The air tanks limit them to 25 minutes per dive. 170 00:22:07,492 --> 00:22:12,156 So they get just a glimpse of how these high sea drifters really live. 171 00:22:20,405 --> 00:22:25,206 Harbison and Madin specialize in creatures of incredible delicacy 172 00:22:25,344 --> 00:22:27,778 known as jelly plankton. 173 00:22:34,386 --> 00:22:37,878 This underwater world changes by the hour. 174 00:22:38,824 --> 00:22:42,590 Many species stay away from the brightly lit surface by day, 175 00:22:42,728 --> 00:22:46,027 so these researchers dive round the clock. 176 00:22:51,336 --> 00:22:53,099 Under the cover of darkness, 177 00:22:53,238 --> 00:22:57,607 a whole new world of creatures rises from the depths. 178 00:22:57,743 --> 00:23:01,042 It is the largest animal migration on the planet, 179 00:23:01,179 --> 00:23:04,205 and it happens every night in the oceans. 180 00:23:10,422 --> 00:23:13,323 This sea snail joins a glorious host of species 181 00:23:13,458 --> 00:23:16,859 as they ascend to feed at the surface. 182 00:23:56,435 --> 00:23:59,598 Life as a jelly is an ingenious adaptation. 183 00:24:01,473 --> 00:24:04,601 There are no hard surfaces to run into on the open sea, 184 00:24:04,743 --> 00:24:07,541 so these drifters don't need a sturdy body. 185 00:24:10,248 --> 00:24:15,151 The gelatinous form gives them the same buoyancy as the water around them 186 00:24:16,755 --> 00:24:22,216 They've evolved for life at sea by becoming organized seawater themselves 187 00:24:28,567 --> 00:24:32,196 Near the surface, the smaller drifters feed on minute plant life 188 00:24:32,337 --> 00:24:34,897 that's been growing all day in the sun. 189 00:24:37,576 --> 00:24:40,477 Bigger animals come up to feed on them 190 00:24:41,146 --> 00:24:44,604 The great oceanic food chain begins here 191 00:24:44,749 --> 00:24:47,616 and everything else depends on it 192 00:25:06,371 --> 00:25:11,832 This weird apparition is a killing machine for small crustaceans. 193 00:25:16,281 --> 00:25:19,910 The writhing arms of this comb jelly startle its victims, 194 00:25:20,051 --> 00:25:22,952 which flee straight into the wing like feeding lobes 195 00:25:23,088 --> 00:25:26,990 at either end and become entangled. 196 00:25:42,841 --> 00:25:46,140 It's easy to become mesmerized by the delicate structures 197 00:25:46,278 --> 00:25:50,442 of some ghostly creature turning gently in the currents. 198 00:25:53,118 --> 00:25:57,054 You can see the beating of the heart through the transparent shell. 199 00:25:59,691 --> 00:26:02,888 Its mouth parts are like an easter lily. 200 00:26:05,263 --> 00:26:08,596 Ocean conditions have reshaped it beyond all our notions 201 00:26:08,733 --> 00:26:11,327 of what a snail should be. 202 00:26:25,750 --> 00:26:27,308 Look in another direction, 203 00:26:27,452 --> 00:26:31,582 and there's a salp chain grazing on small plant particles. 204 00:26:33,658 --> 00:26:36,786 This jelly can reproduce with extraordinary speed 205 00:26:36,928 --> 00:26:39,988 to take immediate advantage of a new food source. 206 00:26:40,131 --> 00:26:44,966 The salp sprouts new individuals like a chain of paper dolls. 207 00:26:54,012 --> 00:26:57,038 The gelatinous form makes for efficient feeding. 208 00:26:57,182 --> 00:26:58,945 It allows this siphonophore 209 00:26:59,084 --> 00:27:02,451 to spin out lengthy tentacles like fishing lines. 210 00:27:02,954 --> 00:27:07,050 It twitches its crustacean-like lures to entice its prey. 211 00:27:14,032 --> 00:27:16,762 In the boundless world of mid-ocean, 212 00:27:16,901 --> 00:27:21,201 with the sea bottom miles below and no other surfaces nearby, 213 00:27:21,339 --> 00:27:24,775 a jelly is the only niche for other species. 214 00:27:26,845 --> 00:27:31,441 One animal's body can become the whole world for another. 215 00:27:33,351 --> 00:27:37,310 A crustacean deposits her offspring on a comb jelly. 216 00:27:41,159 --> 00:27:45,027 As they grow, they devour their host. 217 00:27:46,631 --> 00:27:50,362 Crustacenas eat jellies, and jellies eat crustaceans. 218 00:27:50,502 --> 00:27:54,962 It's a banquet where it's difficult to distinguish the guests from the dinner. 219 00:28:03,014 --> 00:28:05,812 The jellies also prey on one another. 220 00:28:18,797 --> 00:28:22,358 The jelly plankton even have their own great white shark. 221 00:28:22,500 --> 00:28:26,766 The three-inch-long beroe is a jelly with jawa. 222 00:28:28,173 --> 00:28:32,132 Its mouth is lined with sharp, tooth-like hooks. 223 00:28:44,022 --> 00:28:48,857 The beroe latches onto its prey and then expands to engulf it. 224 00:28:54,566 --> 00:28:58,798 This ability to stretch is another advantage of the gelatinous form. 225 00:29:14,219 --> 00:29:15,379 Though scuba researchers 226 00:29:15,520 --> 00:29:18,512 are limited to working in the upper layers of the ocean, 227 00:29:18,656 --> 00:29:20,283 with this submersible, 228 00:29:20,425 --> 00:29:25,226 an oceanographer can study drifting life forms down to 3,000 feet 229 00:29:25,864 --> 00:29:31,268 There the world of the ocean drifters becomes even more fantastic. 230 00:29:49,687 --> 00:29:54,124 Edith Widder studies creatures living in the deep sea currents. 231 00:30:01,633 --> 00:30:05,501 Her pilot maneuvers skillfully as he collects samples 232 00:30:05,637 --> 00:30:08,435 with a battery of scientific equipment 233 00:30:21,386 --> 00:30:24,651 On the way down, they may be the first humans 234 00:30:24,789 --> 00:30:28,987 to see creatures that have drifted here for millions of years 235 00:30:29,627 --> 00:30:32,619 endlessly strange and wonderful. 236 00:30:34,632 --> 00:30:39,467 A siphonophore spirals out into the watery darkness, like a galaxy. 237 00:30:41,206 --> 00:30:46,109 It's maximizing the feeding area for its fringe of stinging tentacles. 238 00:30:59,157 --> 00:31:00,920 Scientists have only recently discovered 239 00:31:01,059 --> 00:31:03,459 this football-size comb jelly. 240 00:31:03,595 --> 00:31:05,859 They call it Big Red. 241 00:31:26,451 --> 00:31:27,941 This fish isn't sick. 242 00:31:28,086 --> 00:31:31,783 In these dark unbounded depths, with no top and no bottom, 243 00:31:31,923 --> 00:31:35,484 everything simply behaves differently. 244 00:31:38,596 --> 00:31:42,362 Like this squid suspended in the stillness. 245 00:31:46,404 --> 00:31:51,034 Or this squid which has developed a transparent gelatinous body. 246 00:31:53,011 --> 00:31:56,777 All the rules are different down here. 247 00:32:16,601 --> 00:32:20,833 Researchers freely admit that what they know about almost any of these animals 248 00:32:20,972 --> 00:32:23,031 is less than a paragraph. 249 00:32:30,381 --> 00:32:33,646 Scientists have given this newly discovered deep-sea octopus 250 00:32:33,785 --> 00:32:35,912 the nickname Oumbo. 251 00:32:53,838 --> 00:32:56,568 Wider specializes in bioluminescence, 252 00:32:56,708 --> 00:33:01,168 the ability of living creatures to communicate by producing light. 253 00:33:06,451 --> 00:33:09,249 To study this phenomenon, she measures what happens 254 00:33:09,387 --> 00:33:13,050 when bioluminescent animals drift into this screen. 255 00:33:13,191 --> 00:33:15,352 She must shut down her own floodlights 256 00:33:15,493 --> 00:33:18,826 and use special cameras to see how they respond. 257 00:33:23,267 --> 00:33:28,603 The pitch blackness of deep water suddenly explodes in a fiery light show 258 00:33:38,549 --> 00:33:41,211 A sea cucumber looks strange enough just before 259 00:33:41,352 --> 00:33:43,411 it makes contact with the screen. 260 00:33:48,026 --> 00:33:52,190 Then it turns on its own lights, and rolls off unharmed. 261 00:34:09,981 --> 00:34:12,472 Almost every animal uses bioluminescence 262 00:34:12,617 --> 00:34:14,847 in the pitch dark of the deep. 263 00:34:18,990 --> 00:34:21,424 Given the abundance of life in the oceans, 264 00:34:21,559 --> 00:34:26,223 This may be the most common form of communication on earth. 265 00:34:39,444 --> 00:34:42,379 The clouds of bioluminescence can be so bright 266 00:34:42,513 --> 00:34:45,846 that they light up the instruments inside the submersible 267 00:34:48,886 --> 00:34:50,080 If attacked 268 00:34:50,221 --> 00:34:54,590 some animals try to confuse their predator with sheer incandescence, 269 00:34:54,725 --> 00:34:57,250 like a flashbulb in the face. 270 00:34:59,163 --> 00:35:02,758 Others illuminate the predator in the hope that some larger predator 271 00:35:02,900 --> 00:35:05,926 will come along like a cop and take it away. 272 00:35:07,705 --> 00:35:11,402 Some use light like a lure to draw their prey close, 273 00:35:11,542 --> 00:35:13,669 or to attract a mate. 274 00:35:15,813 --> 00:35:17,610 In this world of darkness, 275 00:35:17,748 --> 00:35:21,809 the language of light is so important that a moment's flickering 276 00:35:21,953 --> 00:35:25,650 may determine whether an animal lives or dies. 277 00:35:29,727 --> 00:35:32,025 But what we know about bioluminescence 278 00:35:32,163 --> 00:35:35,496 is limited by the difficulties of ocean research. 279 00:35:35,633 --> 00:35:40,002 Even a submersible stays underwater for only about three hours. 280 00:35:47,245 --> 00:35:50,214 The promise of oceanography is tantalizing. 281 00:35:50,348 --> 00:35:54,216 Bioluminescent chemicals are already being used in medicine. 282 00:35:54,352 --> 00:35:58,379 But reaping the potential benefits is dangerous work. 283 00:36:01,826 --> 00:36:06,490 In many ways, it's like the grand adventure of space travel. 284 00:36:06,631 --> 00:36:10,931 But we've mapped the barren surface of Venus in far more detail 285 00:36:11,068 --> 00:36:13,502 than our own deep ocean floor. 286 00:36:23,047 --> 00:36:25,914 Is it worth exploring the depths of this planet? 287 00:36:26,050 --> 00:36:29,281 In one area the size of a small living room, 288 00:36:29,420 --> 00:36:34,915 deep sea researchers recently discovered 460 new species. 289 00:36:36,227 --> 00:36:39,719 Who knows what secrets we have yet to discover in the oceans? 290 00:36:51,242 --> 00:36:52,869 Even back on the surface, 291 00:36:53,010 --> 00:36:56,969 the limits of our knowledge can be painfully apparent. 292 00:36:57,682 --> 00:37:01,345 In the complex ecosystem at the very skin of the ocean, 293 00:37:01,485 --> 00:37:07,321 a whole other world of creatures lives both in and out of the water. 294 00:37:13,531 --> 00:37:17,797 As it moves, the stinging tentacles of the Portuguese man o' war 295 00:37:17,935 --> 00:37:20,699 stream out to gather food. 296 00:37:26,244 --> 00:37:28,542 By raising its gas-filled sail, 297 00:37:28,679 --> 00:37:32,479 the man o' war can travel at varying angles to the wind. 298 00:37:32,617 --> 00:37:35,211 It's an elegant system for dispersing animals 299 00:37:35,353 --> 00:37:39,915 not just where the current takes them, but across the face of the ocean. 300 00:37:48,165 --> 00:37:50,531 Nothing about the man o' war is simple 301 00:37:50,668 --> 00:37:56,368 It's neither an individual animal, nor a colony, but something in between 302 00:37:59,010 --> 00:38:01,035 Joined together under the gas bladder 303 00:38:01,178 --> 00:38:04,238 is a kind of cooperative assembly of stomachs, 304 00:38:04,382 --> 00:38:07,317 tentacles, and reproductive organs. 305 00:38:17,828 --> 00:38:21,093 Other species add to the complexity. 306 00:38:24,902 --> 00:38:26,927 One fish, called nomeus, 307 00:38:27,071 --> 00:38:30,336 hides out among the deadly veil of tentacles. 308 00:38:31,876 --> 00:38:36,142 The man o' war toxin is more potent than the cobra's. 309 00:38:36,280 --> 00:38:38,976 But perhaps because of a protective mucus layer 310 00:38:39,116 --> 00:38:40,879 or greater immune resistance, 311 00:38:41,018 --> 00:38:44,818 nomeus can dine unharmed on the man o' war itself. 312 00:38:56,267 --> 00:38:58,428 Other fish aren't so lucky. 313 00:39:01,305 --> 00:39:05,264 The man o' war can stretch its tentacles out more than 50 feet, 314 00:39:05,409 --> 00:39:09,505 and each tentacle is studded with batteries of stinging cells. 315 00:39:15,953 --> 00:39:20,856 Nomeus may help out the man o' war by herding these fish toward their death. 316 00:39:27,365 --> 00:39:28,696 Triggered by the fish, 317 00:39:28,833 --> 00:39:33,566 the stinging cells fire slender threads lines with barbs. 318 00:39:38,242 --> 00:39:43,270 The victim is lassoed, hog-tied, and injected with paralyzing poison. 319 00:40:06,871 --> 00:40:08,930 Then the digestive organs move in. 320 00:40:09,073 --> 00:40:11,337 Like some monstrous lifeform, 321 00:40:11,475 --> 00:40:13,102 they wriggle and twist 322 00:40:13,244 --> 00:40:16,543 as they fasten their flexible mouths onto the victim. 323 00:40:19,517 --> 00:40:24,853 Gradually, they engulf the fish and dissolve its flesh. 324 00:40:33,798 --> 00:40:35,095 After half a year, 325 00:40:35,232 --> 00:40:39,191 the young loggerheads odyssey has taken her to mid-ocean. 326 00:40:39,336 --> 00:40:41,702 But she still has a lot to learn. 327 00:40:48,112 --> 00:40:51,946 All the activity around the man o' war catches her eye. 328 00:40:53,717 --> 00:40:56,413 She just wants to grab a few fishy tidbits 329 00:40:56,554 --> 00:41:00,149 and doesn't seem to notice the nasty business overhead. 330 00:41:02,793 --> 00:41:07,093 For a moment, the turtle looks like a puppet on a deadly set of strings. 331 00:41:13,704 --> 00:41:16,901 But it's the man o' war that's in danger. 332 00:41:22,580 --> 00:41:27,745 The turtle turns her hungry eye on this intriguing new possibility. 333 00:41:32,122 --> 00:41:35,489 People talk about the first brave human who ate an oyster. 334 00:41:35,626 --> 00:41:39,824 But what a tangled and spicy meal the man o' war must make. 335 00:41:44,201 --> 00:41:48,103 The turtle's skin may be too thick for the stingers to penetrate. 336 00:41:48,239 --> 00:41:51,834 But no one knows what protects the turtle's eyes and mouth. 337 00:42:07,324 --> 00:42:09,451 The loggerhead soon pushes on 338 00:42:09,593 --> 00:42:13,552 in search of a meal that's not quite so challenging. 339 00:42:15,466 --> 00:42:17,866 One of the strangest inhabitants of the harsh world 340 00:42:18,002 --> 00:42:23,030 between air and water is the drifting nudibranch named glaucus. 341 00:42:25,376 --> 00:42:30,814 This upside-down sea slug swallows air bubbles to hold itself at the surface. 342 00:42:35,553 --> 00:42:37,145 With its pointy appendages, 343 00:42:37,288 --> 00:42:41,122 it latches onto anything it's lucky enough to bump into. 344 00:42:41,825 --> 00:42:46,922 But what it's really after are the deadly tentacles of the man o' war 345 00:42:52,670 --> 00:42:56,834 It coats its mouthparts with a mucus layer to protect itself. 346 00:42:59,610 --> 00:43:03,137 The smaller less powerful stinging cells get digested. 347 00:43:03,280 --> 00:43:06,545 But the most virulent stingers remain intact. 348 00:43:06,684 --> 00:43:11,018 Amazingly, they pass directly to the nudibranch's extremities 349 00:43:11,155 --> 00:43:13,885 and it uses them for its own defense. 350 00:43:21,031 --> 00:43:22,498 But these surface drifters 351 00:43:22,633 --> 00:43:26,660 must face adversaries even more formidable than each other. 352 00:43:39,483 --> 00:43:42,646 A storm is brooding up across the water. 353 00:43:43,587 --> 00:43:49,048 It's a reminder of how unstable life must be on the very face of the ocean. 354 00:43:50,628 --> 00:43:54,860 One moment these creatures are being scorched by sun and wind, 355 00:43:54,999 --> 00:43:59,163 and the next they're tumbling in storm-tossed waves. 356 00:44:14,852 --> 00:44:18,913 As the storm passes, they get pelted by icy rain 357 00:44:19,056 --> 00:44:22,992 and have to endure the dilution of their salty home. 358 00:44:29,400 --> 00:44:32,494 Yet the animals living in the ever-changing surface 359 00:44:32,636 --> 00:44:34,968 can seem so delicate. 360 00:44:39,309 --> 00:44:43,473 This drifting snail builds a fragile home of air bubbles 361 00:44:43,614 --> 00:44:48,608 sealed in an envelope of mucus then hangs on for dear life. 362 00:44:48,752 --> 00:44:52,483 If it lets go, it'll sink into the abyss. 363 00:44:56,994 --> 00:44:59,690 The raft is also holding up the snail's offspring, 364 00:44:59,830 --> 00:45:01,661 in these egg capsules. 365 00:45:01,799 --> 00:45:04,859 It's a cradle at the top of a hostile world. 366 00:45:11,308 --> 00:45:12,900 When it's done laying eggs, 367 00:45:13,043 --> 00:45:19,243 the snail builds a new raft for itself and cuts its 50,000 offspring adrift. 368 00:45:45,008 --> 00:45:48,136 Natural debris also drifts in the surface currents. 369 00:45:49,580 --> 00:45:52,674 It's always been a means of dispersal for some plants. 370 00:45:52,816 --> 00:45:54,078 A coconut from the Caribbean 371 00:45:54,218 --> 00:45:56,516 may ride the Atlantic currents thousands of miles 372 00:45:56,653 --> 00:45:58,814 to take root on some distant shore. 373 00:46:01,859 --> 00:46:05,317 Fish are drawn to this kind of flotsam for shelter. 374 00:46:10,501 --> 00:46:14,096 A drifting crate can turn into a small ecosystem, 375 00:46:14,238 --> 00:46:17,765 Where fish lay eggs or find their food. 376 00:46:32,022 --> 00:46:34,582 But the little things we throw away add up, 377 00:46:34,725 --> 00:46:38,957 and the supply of garbage begins to seem endless. 378 00:46:39,696 --> 00:46:43,257 One study estimated that 13 tons of trash per minute 379 00:46:43,400 --> 00:46:47,268 was being heaved overboard by ocean-going vessels alone 380 00:46:48,438 --> 00:46:51,134 A recent treaty now regulates the practice, 381 00:46:51,275 --> 00:46:53,539 but it's rarely enforced. 382 00:47:00,551 --> 00:47:04,043 Whatever goes into the ocean gets drawn into the currents, 383 00:47:04,188 --> 00:47:08,716 and it builds up in the very places where marine life is richest. 384 00:47:17,301 --> 00:47:22,500 Animals encrusted on debris may rouse the loggerhead's hunger and curiosity. 385 00:47:22,639 --> 00:47:27,508 For her, drifting objects have always been a natural food source. 386 00:47:33,083 --> 00:47:38,487 Until recently, a loggerhead could safely eat almost anything she came across. 387 00:47:39,556 --> 00:47:41,615 Nothing in her evolution has prepared her 388 00:47:41,758 --> 00:47:44,386 for this wealth of deadly new choices. 389 00:48:04,381 --> 00:48:09,045 To her, it makes as much sense to pick at the festive remnants of a balloon 390 00:48:09,186 --> 00:48:11,245 as at a man o' war. 391 00:48:13,891 --> 00:48:17,588 Fragments like these can choke turtles to death. 392 00:48:19,863 --> 00:48:24,493 Plastic blocks their digestive tracts and causes starvation. 393 00:48:44,054 --> 00:48:47,251 This time, she's unable to tear off a bite. 394 00:48:47,391 --> 00:48:51,122 But she'll face many more opportunities as she swims on. 395 00:48:53,497 --> 00:48:57,900 Almost every dead turtle found has plastic in its gut. 396 00:49:06,777 --> 00:49:10,873 Millions of seabirds also die each year because of garbage 397 00:49:11,014 --> 00:49:13,847 like this gannet tangled up in debris 398 00:49:13,984 --> 00:49:17,249 absent-mindedly discarded by sportfishermen. 399 00:49:23,427 --> 00:49:26,726 Commercial fishermen lose thousands of miles of net each year, 400 00:49:26,863 --> 00:49:30,765 which spread out all across the oceans like a deadly web. 401 00:49:34,538 --> 00:49:38,599 There may be no way for the loggerhead to learn about these new perilss 402 00:49:38,742 --> 00:49:40,573 until it's too late. 403 00:49:55,959 --> 00:49:58,553 The turtle has survived her first year 404 00:49:59,096 --> 00:50:03,294 But in the long seasons before she circles home to Florida to lay her eggs 405 00:50:03,433 --> 00:50:06,334 a more sinister peril may threaten her 406 00:50:10,007 --> 00:50:11,599 Everything out here 407 00:50:11,742 --> 00:50:15,269 is absorbing a swelling tide of chemical wastes 408 00:50:17,247 --> 00:50:19,010 even the plankton. 409 00:50:22,452 --> 00:50:24,784 Though they may seem insignificant, 410 00:50:24,921 --> 00:50:28,982 the lifeforms here are important to cloud formation. 411 00:50:32,029 --> 00:50:35,055 They even help regulate the global climate. 412 00:50:37,701 --> 00:50:39,566 These microscopic plants and animals 413 00:50:39,703 --> 00:50:43,935 have always struggled against enormous odds to reach maturity 414 00:50:46,043 --> 00:50:48,477 Now they must also absorb heavy metals 415 00:50:48,612 --> 00:50:52,810 sewage, pesticides and petrochemicals. 416 00:50:56,453 --> 00:51:02,323 Plankton is the base of the food chain and every marine animal depends on it. 417 00:51:07,731 --> 00:51:12,930 If our carelessness disrupts this vast drifting tide of life, 418 00:51:13,470 --> 00:51:16,371 will it imperil the entire ocean? 419 00:51:18,341 --> 00:51:22,402 Will it affect the food we eat and the very air we breathe? 420 00:51:26,516 --> 00:51:28,950 No one has yet spent enough time traveling 421 00:51:29,086 --> 00:51:32,419 in the loggerhead's world to find out. 422 00:52:12,262 --> 00:52:14,059 It may be that we humans 423 00:52:14,197 --> 00:52:19,100 will always find it easier to turn our imaginations away from the oceans 424 00:52:19,236 --> 00:52:21,204 and out to other worlds 425 00:52:23,540 --> 00:52:25,940 But as we peer up at the stars, 426 00:52:26,076 --> 00:52:28,442 we should keep one truth in mind 427 00:52:29,246 --> 00:52:32,044 All the alien life forms we know 428 00:52:32,182 --> 00:52:34,707 and perhaps all we ever will know 429 00:52:35,852 --> 00:52:40,312 are here adrift on planet Earth.