"It remained a mystery for a thousand generations... capturing the imagination of those who lived at its edge but could not visit there." "Who could see only dimly into a shadowy world both beautiful and bizarre." "Today, we can enter that world and cast light on it." "Scientific explorers now seek to uncover the secrets of this world." "Some of what we've learned seems remarkably similar to the beliefs of Australia's aboriginal people." "They have endured for 50,000 years by regarding themselves not above nature, but part of it." "Science often takes a different approach... analyzing the living world by dissecting it species by species." "But the aboriginals believe that no living thing exists apart from the greater community of living things that even the human is merely a part of the great system of life." "Science is only now discovering how much the aboriginals have long understood." ""It was unchanged through all of the time of my ancestors." ""From the dreamtime when animals were almost human" ""and people were gods, unchanging." ""The sea, the reef and all that lives here." ""But now, people are no longer gods and change encircles us like the sharks."" "The encroaching modern world is symbolized by vast settlements such as Sydney, Australia's largest city." "But along the same coast lies an ancient underwater city called by aboriginals Wogogaboo." "It is the largest structure on earth built by living things." "The Great Barrier Reef." "More than 2,000 identifiable reefs combine to form a rampart of coral 1,200 miles long extending as much as 120 miles out to sea." "Erected over millions of years it is a feature of earth's surface so immense as to be visible from the moon." "In the great liquid space of the ocean the reef's limestone ramparts and towers loom up like a vast housing complex, providing its residents with shelter from the surging sea and from one another." "Like human cities, the reef is also a place where the hungry can find a meal." "The concentration and interaction of life here makes possible a steady exchange of life-giving nutrients gathered from the surrounding sea." "Ironically, the massive reef system owes its existence to tiny creatures called coral polyps." "Though these diminutive construction workers are plant-like in appearance, they are animals related to jellyfish and sea anemones." "They feed by capturing passing food in their tentacles and protect themselves by secreting a casing of calcium carbonate." "The calcium remains of the polyps are compressed over time into limestone forming the foundations upon which new coral generations build." "An oasis in the desert of the open sea the reef city attracts offshore travelers like the gentle manta ray." "Such visitors enter a world of curious life-forms where things are not always what they seem" "a world where fish can inflate themselves like balloons" "and an eight-legged creature, long portrayed as a monster turns out to be remarkably intelligent and shy." "What appear to be ferns are instead, animals sweeping the water for bits of food." "Here, some mollusks are jet-propelled... and worms perform like Spanish dancers." "A creature shaped like a fierce snake is actually a fish so wary it hides in a hole all day." "What appear to be feathers are poisonous spines." "A pink carnation is actually a worm." "The corals themselves exist in an enormous array of shapes and configurations." "Many of these structures enable them to capture plankton in barren tropical waters." "But to in ensure a steady food supply some corals also grow their own food... a microscopic algae cultivated within the tissue of the cords themselves." "To provide their algae gardens with sunlight corals take on unusual shapes." "The more surface area exposed to the sun the better internal algae gardens grow." "As the coral generations accumulate they rise toward the surface creating a wall between land and sea the barrier which gives this reef its name." "This upward growth is not without risk." "Occasional drops in sea level expose and kill the corals turning reefs to islands." "One such tiny slip of land, Heron Island at the southernmost end of the Great Barrier Reef is home to a research station operated by the University of Queensland." "Scientists from around the world gather here to study the reef ecosystem." "In the station's labs, marine biologists seek to learn how life transpires in the world's greatest underwater city." "Perhaps the most important scientific research takes place not in the labs, but on the reef itself." "Researches by the score visit the Great Barrier Reef annually." "Australians Valerie and Ron Taylor have devoted their lives to underwater exploration and photography." "In three decades of diving here they have helped reveal the enormous complexity of reef life." "Although we dive the reef in the name of science to study, photograph and count the sheer beauty of the place draws us here as much as the desire to better understand it." "The corals form a habitat as lovely and magical as a fairy-tale setting." "For life here, though the coral serves as a vital framework for survival providing catch holds for attaching organisms hiding places for prey and hunting grounds for predators." "A single square meter of coral can sustain dozens of species." "The coral polyps are the landlords extracting as rent the organic debris of their tenants." "The tiny blenny keeps a wary watch from the reef equivalent of an apartment." "Moray eels seek out crevices to occupy like day rooms." "Like many residents the barramundi cod lays claim to a plot and spends much of its time defending it from intruders." "Some creatures, like these bat fish use the reef as a place to hover and rest part of each day." "Many of the fish that swim lightly through the day commute beyond the reef at night to hunt changing places with others that commute back to rest all night on the reef." "The constant search for food permeates existence here." "Hunger can even lead small fish to risk approaching a much larger stranger in the hope of finding something to eat." "Offer food, and the fish flock like birds in a city park." "Not every creature here is a resident." "The jellyfish is a passer-by occasionally swept over the reef as it rides the currents." "Most animals, like the shovel-nosed skate seem timid in the presence of divers." "But the Taylors have learned to be on the lookout for a notorious creature less likely to flee." "The abundance that draws divers to the reef also attracts sharks." "Some sharks are permanent residents who survive by being masters of deception." "The wobbegong, or carpet shark has developed near-perfect camouflage making it difficult to tell coral from carnivore." "It escapes the notice of enemies while lying in ambush for prey." "Because of their long experience diving the reef the Taylors have often led scientific expeditions to study the deepwater sharks lured to this rich hunting ground." "Though frenzies are believed uncommon sharks grow aggressive when food is on their midst whether provided by nature or by humans seeking to observe their behavior." "These bronze whalers provide a rare glimpse of the streamlined power of animals fashioned by evolution into beautiful and near-perfect hunters in the sea." "Patrolling the edges of the reef sharks serve a vital function." "They eliminate the weak and, over time, strengthen the breeds of the very species they prey upon." "The history of the reef is a chronicle of constant change." "More than 25 million years ago corals began to fringe Australia's eastern coast." "Across eons, ice ages lowered the sea levels exposing and killing reef coral until the climate began to shift and global warming melted the ice allowing fresh veneers of coral to return." "Though most of the reef's story remains hidden beneath the surface we can more readily trace the history of the scattered islands looming up from it." "When the seeds and spoors of life reach these fertile outposts on the wind or currents lush miniature worlds are born." "The islands provide both sustenance and habitat for some of the largest bird colonies in the tropics." "The life of the islands is inextricably linked to the encircling sea." "Nutrients are cycled from fish to bird to guano fertilizing luxuriant vegetation." "These islands are also the birthplace of another creature of the sea." "Each year, on summer's tides, under the protection of night and ancient drama of reproduction unfolds." "From birth, sea turtles are ocean wanderers." "But at the age of 30, they begin to return every year across thousands of miles of open sea to reproduce young of their own on the very same beaches where they were born." "After mating at sea the female laboriously pulls herself ashore where she digs an egg chamber in the sand." "In a single night, she will lay as many as 180 eggs then cover them with sand and return to the sea." "The hidden eggs incubate over eight to ten weeks protected by sand from sea birds and other marauders." "When the hatching emerge instinct propels them toward the ocean in a race to escape island birds." "Perhaps only one in a thousand of these hatchlings will return in 30 years to reproduce... enough to ensure the perpetuation of the species." "Beyond the marvels of ocean life researchers are also making discoveries that could yield invaluable products for human life." "Scientists are already finding species here with immunities against many diseases." "The reef is a kind of living laboratory where survival prompts exotic adaptations." "Juvenile fish developed from eggs drifting in the currents congregate near the reef." "When mature they move out together as schools." "The shimmering array of fish and the ability of every individual in a school to instantly and simultaneously shift course presents a disorienting target to would-be predators." "A diver roaming the reef will encounter as many strategies for self-defense as there are potential dangers in the surrounding sea." "For those creatures not blessed with great speed a suit of armor can provide a portable hiding place." "For invertebrates such as the lobster a shell serves a dual purpose as both shield and skeleton." "Lacking a shell of its own the hermit crab turns an empty shell into a kind of mobile home... while the spider shell fashions a shelter camouflaged to be mistaken for coral." "No method of defense is foolproof." "A crab suddenly caught in the open is vulnerable to attack." "Opportunistic predators quickly zero in on the crab's vulnerable underbelly." "The hard limestone casing secreted by corals provides polyps with a secure shelter impervious to most predators." "Yet, there is one devastating exception the crown-of-thorns starfish." "Emitting digestive juices that kill polyps the crown of thorns can wreak havoc." "In occasional population explosions that ravage immense tracts of the Great Barrier Reef the crown of thorns literally eats itself out of house and home." "The crowded conditions of the reef have prompted organisms to develop elaborate chemical weaponry." "Nudibranchs, defend themselves simply by tasting bad." "To advertise their distasteful nature and discourage predators they've developed gaudy color schemes illustrating a rule of the reef... bright colors mean, "Don't eat me"" "which may explain why there are so many colorful creatures here." "The florid beauty of the anemone can be deceptive." "Capsules on the tentacles of some anemones fire poison darts that paralyze anything, from plankton to fish." "Yet, small clown fish have adapted to living within the deadly weaponry protected by a mucous coat." "The clown fish escape predators by remaining close to the stinging anemone even using it as an egg nest." "In turn, the nearly immobile anemone can capture and eat curious predators lured to its side by the presence of the tiny clown fish." "The lion fish displays the bright coloration of a chemical warrior." "The feather-like spines contain a powerful toxin capable of paralyzing or killing an attacker." "Among the most venomous of all marine creatures is the puffer fish best known for swelling up to make itself difficult to swallow." "Many puffers also carry a nerve poison in their organs so powerful that predators risk death from respiratory paralysis if they eat a puffer." "The study of reef toxins has already shed light on the nature of nerve and muscle disorders." "We may find that substances deadly on the reef can be turned by science into remedies for human ailments." "At night, the mood of the reef transforms." "Shifts change in the reef city." "Herbivores that graze by day are replaced by carnivores that hunt by night." "None is better equipped than the shark." "In complete darkness, the shark can locate prey by sensing the electrical fields of quarry and homing in on them." "In the sea, the shark is master of the night." "For many creatures night is simply a time of inactivity, and even sleep." "The crevices and corridors of the reef city offer a profusion of hiding places for the drowsy." "To rest in safety the parrot fish surrounds itself with a mucous cocoon a transparent sleeping bag that hides its scent from night hunters." "Too skittish to be approached closely in daylight the creature is so docile at night it can be examined carefully then returned to its sleeping chamber." "Tentacles retracted all day by many corals are now extended to sting and capture plankton." "The reef comes alive with millions of Medusa-like tentacles." "A few nights each year the Great Barrier Reef is the scene of a mass spawning that may be unparalleled on Earth." "Billions of coral polyps across thousands of square miles spew a storm of eggs and sperm into the water often within minutes of one another." "The floating blizzard of new life is attacked by a frenzy of worms and countless tiny predators" "but enough spawn survive to create a new coral generation." "The spawn will drift far before sinking." "The progeny of one reef can ensure the future of others far in the distance." "Lighthouses and markers reveal an ominous side of the reef." "Though a haven for sea life, it is a mortal enemy of ships." "Even steel hulls can be ripped open by hidden coral heads." "There have been more than 1,200 shipwrecks on the Great Barrier Reef in this century alone." "The freighter Cooma went aground in 1926." "To divers, its crumbling remains are a haunting reminder that it once served as a human home." "Yet, to creatures of the sea the sunken ship is merely a new building site." "Legions of polyps and other encrusting colonizers gradually overwhelm deck plates and superstructures in a process that will ultimately entomb the steel remains beneath layers of life, creating an artificial reef to be settled like a new suburb of the city." "Researchers have assumed a leading role in the preservation of this ecosystem." "They have been directly responsible for the protection of many threatened species." "Through the efforts of many concerned people like the Taylors the Great Barrier Reef was established as a marine park by the Australian government." "The Great Barrier Reef is a monument to life." "Tiny living organisms built it all, created a reef larger than all the structures of Man." "We have only glimpsed the astonishing diversity and complexity of its life." "We find wonder and beauty in something as simple as a hermit crab." "It is important that we share that wonder that we care for this priceless heritage for ourselves, for our children for all the generations to come." "We are learning more and more about the Great Barrier Reef and the myriad species which exist within it." "Yet here, perhaps we may learn most about our own species." "On the reef, we may learn whether we are only a predator grown so powerful and uncaring as to harm a magical realm of life or whether, with all our powers we have grown to respect life in all its forms" "and to leave all its splendid torches burning." "All living things are one like the blood which unites one family." "All of life forms one great web." "Man did not weave the web of life." "He is only a part of it." "He is only a strand within it." "Whatever he does to the web of life he does to himself."