"Our universe seems a barren place ... full of extreme conditions hostile to living things." "Our own planet has such extreme environments." "Places where, until recently, we believed nothing could survive." "Yet life is tenacious if it can just get a foothold." "We call the tiny organisms living in such inhospitable places extremophiles ... microbes which thrive in the harshest of conditions." "Caves, long dismissed as dark and lifeless deserts, turn out to be ideal homes for these hardy life forms." "Their scientific potential appears vast." "This underground frontier ... holds an irresistible attraction for two courageous young women." "The Arizona desert, bone-dry and scorching-hot." "Perfect for extremophiles." "Nancy Aulenbach and Hazel Barton ... are part of a small team exploring unmapped caves ... near the Grand Canyon." "The rest of the team, Gordon Brown and Scott Davis, search for other caves." "Hazel and Nancy are almost certainly the first cavers to explore this cave." "To get here they rappeled 300 ft. in 112 degree heat." "Nancy Aulenbach from Georgia is the team's technical specialist." "As an instructor in cave rescue techniques," "Nancy's rope skills are finely honed." "At 98½ pounds, she is well suited for rescuing cavers stuck in very tight places." "In unexplored caves we always do surveys." "Later my husband will use our data to draw the very first map of this cave." "He is a caver." "In fact, I come from an entire family of cavers." "Hazel Barton, a native of England has a PhD in Microbiology." "I found crystals which only form in still water." "This cave probably formed millions of years ago." "While Nancy studies the cave wall with a magnifying glass," "Hazel collects samples of tiny organisms ... which could help cure serious diseases." "You are never sure what speck of dust might contain the secret to a new medicine ... that could save lives." "Often, the most dangerous part of exploring caves is just getting to them." "Gordon will vouch for that." "What turns this river so blue is dissolved limestone." "The limestone is gradually re-deposited ... to form travertine dams ... which are first cousins to the stalagmites we see in caves." "All this blue water and travertine ... is visible proof that caves are forming upstream right now." "I got time-off from my job as a teacher's assistant ... because I promised to e-mail field reports back to my second-grade students." "Here is how Hazel described her research to my second-graders:" "The tiny organisms called microbes that live in caves ... might contain special chemicals that we could make medicine from." "You know caves are not only a place to visit, they are a place where you can do a lot of research, you can survey, you can do biological inventories, you can find new species that people have never seen before." "I look for medically useful organisms everywhere, even in scum ponds," "after all a rather useful medicine called penicillin ... was found in the same mould that grows on rotting cheese." "You know, just collecting some more boogers, the smellier the better." "While we were on Navajo land," "Nancy and I heard about a medicine man ... making a sand painting." "Through these sand paintings, the Navajo believe that they can tap into the healing powers of the earth." "Of course that's what I do too," "I go deep into the earth in search of unknown cures." "We are using kayaks on this expedition ... because the river is a good vantage point ... for spotting unexplored caves on the cliff walls." "As my husband, Brent, says," ""if you aren't wet you aren't caving"." "Some rivers run through caves for miles before bursting on to the surface, but that's of little concern as you approach a precipice wondering ..." ""is this a good idea?"" "Unlike canyons, which are carved by fast moving rivers, caves are formed by a subtler, but equally effective, force." "Most limestone caves start when groundwater picks up carbon dioxide in the air and soil." "As the mildly acidic water leaks through cracks in the earth's crust, it dissolves the surrounding rock, leaving pockets, caves." "That's how a chamber 300 ft. high can be carved from solid stone ... in less than a million years." "Walls are decorated when trickling water-deposits dissolve stone ... to form stalagtites, stalagmites and other flow-stone formations." "Since the purest water on earth is found deep in pristine caves, sometimes we use rafts to explore, which cause less contamination than swimming." "Cave decorations are as delicate as fine crystal, easily shattered and impossible to repair." "That's why good cavers are trained to move gently underground." "When water leaves a residue of minerals, they crystallise and gradually build up ... to become delicate cave formations." "As Hazel and her colleagues in the lab have found, extremophiles are tough." "We suspect that, because of the environment in which they live, extremophiles produce potent chemical weapons." "If we can isolate these chemical compounds, we can use them in the fight against disease." "Only the hardiest extremophiles could survive ... deep in the ice of the North Pole." "To collect them," "Hazel and Nancy have joined an Arctic expedition ... to Greenland." "Greenland's ice cap is massive." "If melted, it would raise the world's oceans 18 ft." "When I first saw camp and saw all these tiny specks out in the middle of nowhere, you know I started thinking ..." ""we are going to be here for awhile"." "The expedition is led by Frenchman Janot Lamberton." "Janot has gone deeper into ice caves than anyone else alive." "In summer, melting ice creates raging rivers, which plunge into the caves, cutting them deeper and deeper." "Heat from the sun can weaken ice." "These jumbled blocks were once the roof of a cave ... just like the one we are about to venture into." "We started early so we wouldn't be inside when the roof collapsed." "Once I dropped into the cave," "I focused on how awesome it was to be ... one of the first people to see that place." "The ice is alive and you can hear it creak and groan ... as it all inches very slowly towards the sea." "The ice is a databank, storing centuries of information for the team's glaciologist," "Dr Luc Moreau." "And also the ice is a memory of the climate." "You see different layer ... a blue layer represent the summer ... and white layer represent the winter, so we can calculate the age of the ice here." "The glacier is truly a time capsule, the deeper you go, the more the seasonal layers are compressed." "Only 60 ft. down," "Hazel can collect samples which fell as snow, centuries ago." "Err so far we so far found just bunches of different bacteria:" "gram negative, gram positive, cocci, spyrokeets ... all kinds of cool looking stuff, and the thing is there's not much I can do with them here in the field, the only thing I can do this freeze them down and take them back with me." "The bacteria Hazel wants most ... lie buried beneath 500 ft. of ice." "The team cannot descend the deep until there is a four day cold snap ... to stop the flow of water." "They soon get their wish." "The other day it was -12 centigrade with a windshield of -26 centigrade ... which is colder than a freezer ... so it was very cold, bitterly cold." "Big-time." "Too cold to be pleasant." "Waiting for the water to freeze up is the hardest part, because we're out in the middle of an ice cap, there's not a whole lot to do." "This is definitely a caver's haircut." "To prepare for the deep descent," "Nancy has to learn to measure the movement of the ice, as the cave walls are slowly pushed in by the tremendous weight of the glacier." "Oh, so from this point to this point ... is what we measure how it closes, okay." "Four days into the cold snap," "Janot decided to risk perhaps his deepest descent ever, to get samples for Hazel." "Only days ago this was a deadly waterfall." "The deeper you go, the more unstable the ice becomes." "Janot has seen ice boulders burst from the walls like cannon shots." "10 foot spears can break loose without warning." "So he purges the walls of loose ice, to protect the team members who will follow." "Sometimes to set ice screws in the safest spot," "Janot turns himself into a human pendulum." "Assisting Janot on the descent," "Luc is concerned about dripping water ... icing up the rope at 200 ft." "I have rappeled under hundreds of vertical pits around the world, but never anything like this." "Ice adds an element of unpredictable risk." "At just over 500 ft.," "Janot grows increasingly concerned about the instability of the ice." "This is the second deepest ice cave Janot has ever explored." "As Hazel rappels," "Janot radios up and warns her not to descend too far." "Instead, he will bring her the deepest sample." "A large block of ice above Janot seems ready to break loose." "He wastes no time in collecting the samples for Hazel ... before starting the long climb back out." "Perhaps the microbes Janot risked his life for ... will one day offer a cure for disease." "But it will take years of research to unlock that secret." "Some extremophiles can stay out here for 100 years, but I have found a few weeks was quite my limit." "I knew I would miss my new French friends though." "When you go caving with someone, you trust your life to them ... and they to you, you become friends for life." "The hills near my home in Georgia ... are ideal terrain for the formation of caves." "Just as extremophiles thrive in the ice cap of Greenland, bats are well adapted to classic limestone caves." "These flying mammals sleep all day and come out at sunset to feed." "40% of all bat species are endangered, but not this colony." "The 20 million bats here eat a half a million pounds of insects every night." "Thanks to special training," "Nancy can introduce her class to this ... under appreciated creature on a field trip." "Any questions?" "What to do bats eat?" "Well, this kind of bat eats, scorpions." "Do you believe that?" "I wouldn't want to eat a scorpion, would you?" "And bats eat a lot of insects too, they get rid of those nasty mosquitoes that bite your legs, make you itch." "Like bats, serious cavers will go a long way to find a good cave." "So when Hazel invited me on another far flung search for extremophiles," "I was raring to go." "Southern Mexico, the Yucatan peninsula juts defiantly into the Gulf." "These ancient Mayan temples ... were built on one huge limestone plateau." "The plateau holds hundreds of miles of cave passage, the longest underwater cave system in the world." "The caves are entered through cenotes, natural wells." "How did it go, did you all find anything?" "Hey kids, I'm still down here in Mexico with Hazel, and we are looking for something called a halocline." "A halocline is where the freshwater from the stream, like this, meets the salt water of the ocean, and it forms this really blurry layer." "You see this blurry layer?" "Hazel thinks there are some special bugs which live in this halocline, so that's why we are looking for it." "Well, that's about it for right now." "And I love you all and give yourselves a big hug from me." "Goodbye." "To find an uncontaminated halocline, our guide, Jorge Gonzalez, led us to a remote cave, deep in the jungle." "If the freshwater in this cave flows all the way to the sea, it must pass through a halocline." "To find out, Nancy and Hazel used fluorescein dye, which does not harm the environment." "If this green dye comes out where we expect, at a coastal lagoon, then we will know that this cave is connected directly to the sea." "Hazel retrieved the water collector she placed at the mouth of the underground stream the day before." "The slightest trace of fluorescein will show up under my black light." "Since the green dye went through to the ocean, we went back to the cave the next day." "I respect Hazel's decision to take up cave diving, but I promised my family I'd never do it." "Cave diving has been called the most dangerous adventure in the world." "Survival takes training, caution and luck." "We are laying a dive line, it is a bit like leaving trail of breadcrumbs ... to find your way back home." "Jorge affixes arrows to the line, to guide the divers back to the exit." "There are rules that we never break." "We always turn around and head for the exit ... when we have used up third of our air, so we have extra air in case we run into problems on the way out." "Life in total darkness has made this species of fish blind." "To compensate, its other senses have become more acute." "When debris rains down from the ceiling, you know that no one has ever been this way before." "If the silt gets kicked up in a huge cloud and you lose sight of the dive line, you may never find it again." "And you could run out of air before you ever find your way out of the cave." "When we reached a breakdown pall," "I wasn't sure if I could get through the small passage, but the volume of water flowing through ... suggested that was more cave on the other side, so I had to find out." "Open ocean divers wear scuba tanks on their backs, but cave divers go sidemount, so we can squeeze through narrow passages." "In any really tight spot, you can remove your tanks, push them ahead ... and then follow them through the hole." "We were approaching our turnaround." "I will not break that rule, no matter what." "Just when the cave seemed to be reaching the right depth for a halocline, we hit a dead end." "In the few moments it took for us to hunt for an opening, we kicked up a huge cloud of silt." "As soon as Hazel and Jorge worked their way out of the silt cloud, they headed for the exit." "Just because fluorescein dye makes it through a passage, that doesn't mean that we can." "You don't look too happy, what happened?" "I wasn't in much of a talking mood but my mind was made up, we'd try a different cave." "The rainforest is an important source of new medicines ... due to its biological diversity." "A great variety of cave life ... is starting to prove just as productive." "I wanted more biological diversity, but the arrival of the rainy season meant that time was running out ... we needed to find the halocline fast." "We saw a chain of cenotes, perhaps connected by an underground river." "I got GPS coordinates on the biggest cenote in the chain, a good starting point for the next dive." "We decided to use scooters ... to give us more range in our hunt for the halocline." "As the sunlight disappeared behind us," "I felt what all scientists feel in their guts ..." ""here I go again, into the black void"." "There was already a dive line for us to follow, toward the ocean." "Someone had been here before us, but when?" "It was spooky when the dive line ran out." "This must be where our mystery trailblazer turned back." "We made an educated guess as to where the underground river comes out." "That's where I'm headed with my GPS." "Still no halocline, but the cave was getting deeper, so I had a good feeling about our chances as we continued downstream." "The elusive halocline." "When we got our glimpse of it downstream, we anchored our scooters ... to keep the propellers from disturbing the halocline." "I knew from the blurry layer, that it was definitely it, a well-defined and uncontaminated halocline." "Anything living in this boundary between the salt and fresh water is, by definition, an extremophile ... with a unique system for survival." "I made sure to collect from different levels of the halocline, to increase the variety of the samples." "My samples from the halocline are very precious." "Who knows what cures may be waiting in the samples I collected today." "Unfortunately, I will have to wait a long time to find out ... because it can take years to approve and test a safe new drug." "For the moment, all I know is that I am very, very happy." "I got it." "You got it?" "It may seem I'm this free-spirited scientist, but I'm really part of the research team." "My colleagues count on me to bring back unique microscopic life." "Often I don't find what we were looking for, but I find something else, totally unexpected, and just as it useful." "Life is full of surprises." "A powerful microscope can reveal a whole universe in a drop of water." "In just six short years ... the search for extremophiles ... has produced a potential new treatment for leukaemia, and added 12 new kingdoms to the tree of life." "Each kingdom is distinct from the others ... as, say, a cabbage is from a dolphin." "Just when we think we have seen every inch of our planet, we find somewhere else we haven't looked." "Remote, mysterious places of extreme potential, places where the horizon turns inward ... and waits for cavers to expand it for us all." "I am going to be caving until my body completely falls apart." "I'm going to do everything possible ... that I can contribute to the world of caving, in my wheelchair if I have to." "I'm always going to be caving in my heart, always."