Exploring the Alien World of Brine Pools

The first time you dive on a site, you don't really know what to expect. It's this magical discovery moment where you tingle all over. And what I try to imagine is, if it wasn't on Earth, where would it be? What could this system represent in terms of understanding life on other planets as well as early life on Earth? In the Gulf of Mexico, there are hundreds of brine pool ecosystems. We've explored less than 10. What we've learned is that every single one is unique. And that means the microbiology is unique and could have very, very real potential for biotechnology and medical use. We're just getting underway in the Gulf of Mexico, where I first began diving in the 1950s. Our destination is to visit these remarkable places known as brine pools, lakes of highly saline water that are actually under the ocean. We're diving into the history of life on Earth. We have the technology to access the deep sea and know about the life that is here. My name is Gavin Thurston and I'm a director of photography, predominantly shooting here in the submarine. And we are ready for the water. We're passing through the twilight zone where the sunlight fades into the eternal darkness. Most of life on Earth lives in the dark all the time. The number of creatures that just float past that nobody has ever seen, it's almost like they're from another planet. As our lights slowly light up the brine pool, you could see a ring of mussels living around the edge of this pond. This pond has got a misty layer on the top, almost like a witch's cauldron. It's an amazingly diverse, complex ecosystem. And you're watching it interact right in front of you through six inches of acrylic. You could see these hagfish and things swimming through this landscape. It's just extraordinary. The hagfish are just prehistoric. They've been around for tens to hundreds of millions of years. They're the only animal that I've ever seen dive into the deepest parts of that brine and come out and not be faced. We filmed quite a few fish just dying before our eyes because they've made the mistake of dipping into the brine. But the hagfish can dive in and actually feed on these dead fish without being affected by the salinity of the brine. There's more diversity of life in the deep seabed than there is in tropical rainforests. The bacteria that live in these brine pools may hold cures to diseases. It's really important that we study them and understand them. The seafloor isn't a barren desert. It's so incredibly alive and it's connected to the surface. The greatest era of exploration is still ahead of us, but we know enough to know that we're vulnerable to what we do to the Earth. We can see what we could not understand before. Exploring a place like this can help provide a piece to the big puzzle. It's quite extraordinary to think that in the next five or ten years they're planning to send a spaceship up to Mars with people in it. In a way you think, oh, why are we so excited by traveling to Mars when under our feet we've got things we've never seen before? This is more than just exploration. There's a very high probability that there are payoffs above and beyond just the basic science. Biomedical, cures for disease, those kinds of payoffs, you can't put a price tag on those. And the fact that we've got ecosystems that have been barely explored and are being damaged by human activity means that we're losing stuff before we even know that it's there.