Shadowing Practice: Why Almost All of the Ocean is Still Unexplored? - Learn English Speaking with Video
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You are standing on a beach.
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The water in front of you stretches to the horizon.
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Behind you is everything you know.
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Every city.
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Every road.
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Every person you've ever met.
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All of it fits on the part of Earth that isn't covered in water.
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Now look at the water.
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That's 71 % of the planet.
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And almost none of it has ever been seen by human eyes.
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Not mapped.
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Not photographed.
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Not touched.
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Just dark.
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We have better maps of Mars than we do of our own ocean floor.
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We have sent humans to the moon six times.
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We have rovers crawling across the surface of a planet 140 million miles away, sending back photos in real time.
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And we have seen less than 5 % of what's directly beneath us.
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5%.
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Here's the first thing you need to understand about the ocean.
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It is not one thing.
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When you picture the ocean, you probably picture the surface.
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Waves.
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Sunlight.
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Maybe some fish near a coral reef.
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That's the part we know.
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That's the part that gets the documentaries.
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But the ocean has layers.
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And the deeper you go, the less any of it resembles the world you know.
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The first layer, the sunlit zone, goes down to about 200 meters.
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This is the part we've explored.
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This is where your mental image of the ocean lives.
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Warm water, light, recognizable creatures, then the light starts dying.
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From 200 to 1 ,000 meters is the twilight zone.
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Dim.
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Cold.
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The pressure here is already enough to crush a human body if you're not in the right vessel.
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The creatures here live in near darkness.
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Some of them make their own light, bioluminescence.
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Tiny pulses of blue and green in water that no sunlight reaches.
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Below 1 ,000 meters is the midnight zone.
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No light at all.
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Ever.
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Complete permanent darkness.
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The pressure is 100 times what you feel at sea level.
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The temperature hovers just above freezing.
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And things live here.
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Things we have no complete record of.
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Below 4 ,000 meters is the abyssal zone.
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The word abyssal comes from the Greek word for bottomless.
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The people who named it knew what they were doing.
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And below that, in the deepest trenches that cut through the ocean floor like scars in the planet,
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is the Hadal Zone, named after Hades, the underworld.
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The deepest point we know of, the Challenger.
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Deep in the Mariana Trench, sits at nearly 11 ,000 meters below the surface.
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To give you a sense of that depth, if you dropped
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Mount Everest into the Mariana Trench, the peak would still be more than a mile underwater.
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We have sent humans there exactly three times in history.
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Three.
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So why haven't we explored it?
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The short answer is that the ocean is trying to kill you.
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Not personally, not with intent, but the physics of the deep ocean are so hostile to human life
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that every meter downward is a negotiation with forces that don't care whether you survive.
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Pressure is the main problem.
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At sea level, the atmosphere pushes down on you at about 14 .7 pounds per square inch.
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Your body is built for this.
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You don't notice it.
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At 10 meters underwater, that pressure doubles.
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At 100 meters, it's 10 times the surface.
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At 1 ,000 meters, 100 times.
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At the bottom of the Mariana Trench, the pressure is more than 1 ,000 times what you feel right now.
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Put a styrofoam cup on the outside of a deep sea submersible and bring it back up.
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The pressure will have compressed it to the size of a thimble.
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Now think about what that pressure does to a human body without protection.
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The vessels we use to explore the deep ocean have to be engineered to withstand forces that would collapse most structures instantly.
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They have to be perfectly sealed, perfectly pressurized, perfectly maintained.
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And even then, they are tiny.
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One or two people maximum.
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Moving slowly, limited battery life, limited oxygen.
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The Titanic, sitting at 3 ,800 meters, wasn't fully mapped until relatively recently.
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It took specialized robots days to document a single shipwreck.
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Now multiply that by the entire ocean floor, 361 million square kilometers.
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At the rate we've been going, it would take thousands of years to map it all with current technology.
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But here's where it gets genuinely unsettling.
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We're not just missing geography, we're missing life.
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The deep ocean is the largest living space on Earth by volume.
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More than 95 % of the habitable space on this planet is ocean water, and the vast majority of it has never been observed.
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Scientists estimate there are somewhere between 700 ,000 and 1 million species living in the ocean.
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We have formally identified around 250 ,000 of them.
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That means there are potentially hundreds of thousands of species, entire forms of life that no human has ever seen.
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Not small things.
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Not microbes.
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We're talking about creatures large enough to have been spotted occasionally, half -glimpsed, and never fully documented.
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Creatures that exist in complete darkness at pressures that would kill you instantly.
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Creatures that have evolved over millions of years in conditions so extreme they barely resemble anything alive on the surface.
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In 2021, a new species of whale was discovered.
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A whale.
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Something the size of a bus, living in the ocean for its entire evolutionary history.
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And we didn't know it existed until 2021.
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If we're missing whales, what else are we missing?
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Here's a list of things we have found in the deep ocean, just to give you a sense of what's down there.
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The giant squid.
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For centuries, sailors reported seeing enormous tentacled creatures in the open ocean.
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Scientists dismissed it as myth.
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Exaggeration.
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Folklore.
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Then, in 2004, a Japanese research team captured the first photographs of a living giant squid in its natural habitat.
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It was real.
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It had always been real.
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It just lived deep enough that we never saw it.
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The giant squid can reach 13 meters in length.
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Its eyes are the largest of any living animal, up to 30 centimeters in diameter.
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Built for darkness, built for a world we can barely reach.
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Then there's the giant isopod.
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If you took a common pill bug, the small crustacean that rolls into a ball in your garden, and scaled it up to 50 centimeters,
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you'd have a giant isopod.
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They live on the abyssal plain, scavenging whatever falls from above.
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Whale carcasses, Dead fish, whatever the darkness provides, and the Dumbo Octopus, named for the ear -like fins it uses to move through the water.
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It lives deeper than almost any other octopus species.
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It's soft and almost translucent, and it moves through complete darkness with a kind of slow grace that looks nothing like anything alive near the surface.
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These are things we know about.
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Now think about what we don't know about.
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In 2018, researchers dropped hydrophones, underwater microphones, into the Mariana Trench.
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They left them there for three weeks, recording everything.
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What they heard was not silence.
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There were sounds that matched known sources.
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Earthquakes, passing ships, whale calls from thousands of miles away, traveling through the water with impossible clarity.
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And there were sounds that didn't match anything in the catalog.
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Low, slow sounds.
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Biological in quality, meaning they had the character of something alive producing them, but not matching any identified species.
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The researchers published their findings carefully.
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They didn't claim monsters.
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They said, there are unidentified biological sound sources in the deepest part of the ocean.
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That's the scientific way of saying, something is making noise down there, and we don't know what it is.
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This is not new.
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In 1997, NOAA, the National Oceanic and Atmospheric Administration, recorded something from a hydrophone array in the Pacific Ocean.
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A sound.
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Extraordinarily loud, low frequency.
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It traveled thousands of miles through the water, picked up by sensors more than 5 ,000 kilometers apart.
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They called it the Bloop.
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It was the loudest unidentified underwater sound ever recorded at that time.
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For years, no one knew what made it.
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Scientists ruled out submarines, ruled out geological activity.
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The sound had biological characteristics, meaning it had the signature of something living.
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The source was eventually attributed to icequakes, the cracking and calving of large ice sheets in Antarctica.
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That explanation is now widely accepted.
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But for a decade, the bloop sat in the catalog of unexplained sounds from an ocean we can barely see into.
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And here's the thing.
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The explanation took a decade, from an ocean we monitor constantly, from a planet we've lived on for 300 ,000 years.
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Imagine what's making sounds we haven't even detected yet.
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Let's talk about hydrothermal vents.
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In 1977, a submersible called Alvin descended to the ocean floor near the Galapagos Islands.
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The researchers on board were expecting what everyone expected at that depth, cold, dark, barren rock.
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The deep ocean floor was assumed to be essentially lifeless.
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Too dark for photosynthesis, too cold too far from the sun -driven energy that powers almost all life on Earth.
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What they found instead rewrote biology.
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Hydrothermal vents.
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Cracks in the ocean floor where the Earth's internal heat pushes superheated water, sometimes above 400 degrees Celsius, up through the rock.
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The water doesn't boil at that depth because the pressure is too extreme.
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It comes out like a black cloud, full of minerals, full of hydrogen sulfide, a chemical that's toxic to most life on Earth,
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and clustered around these vents in complete darkness, At crushing pressure, in water laced with toxic chemicals, was an entire ecosystem.
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Tubeworms 3 meters long, colonies of clam, shrimp with no eyes, navigating by heat receptors on their backs, bacteria that didn't need sunlight at all,
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bacteria that ran entirely on chemical energy from the vents, chemosynthesis.
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An entirely separate way of being alive, a complete parallel food web, an ecosystem that had no relationship to the sun whatsoever.
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Before 1977, we did not know life could work this way.
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And we found it by accident.
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In one place.
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On an ocean floor that stretches for 361 million square kilometers.
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How many more vents are there?
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How many more ecosystems we've never seen?
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Here's something that should bother you more than it probably does.
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We've lost things in the ocean, not small things.
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In 2014, Malaysia Airlines flight MH370 disappeared over the southern Indian Ocean.
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One of the most sophisticated search operations in aviation history began.
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Hundreds of millions of dollars.
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Ships from multiple nations.
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The most advanced underwater detection technology available.
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We searched for two years.
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We found almost nothing.
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The ocean floor in that region was so poorly mapped that search teams were essentially working blind.
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Sonar equipment designed for other purposes had to be repurposed.
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The terrain was unknown.
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Mountains and valleys on the ocean floor that no one had ever charted were discovered during the search.
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Discovered because a missing plane forced us to look at a part of the planet we'd never examined.
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A 777 aircraft, 60 meters long, missing for years.
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In an ocean on a planet with satellites, GPS, and real -time global communication.
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We found a few pieces of debris.
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The main wreckage has never been confirmed.
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That's the ocean.
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The deep ocean also has a memory problem.
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And it's ours, not the ocean's.
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Everything that's ever sunk is still down there.
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An estimated 3 million shipwrecks rest on the ocean floor.
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Most of them have never been found.
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Most of them never will be.
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Some of them are ancient, Greek trading vessels, Roman galleys, ships from civilizations that no longer exist.
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Some of them contain cargo that would rewrite history if we could retrieve it.
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Some of them contain things we'd rather not find.
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During the Second World War, hundreds of vessels were sunk in the Pacific and Atlantic.
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Many of them still carry fuel.
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As the metal corrodes, dirt, and it is corroding, that fuel will eventually leak into an ocean we're still trying to understand.
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From wrecks we haven't located, in places we haven't mapped.
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We are inheriting the consequences of things we sank and forgot about.
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There's one more layer to this.
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The deep ocean isn't just unknown to us.
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It's changing.
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Ocean temperatures are rising, the chemistry is shifting, acidification is altering the conditions that deep sea ecosystems evolved over millions of years to depend on.
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We are changing the deep ocean before we've ever seen it.
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Whatever is down there, the species we haven't cataloged, the ecosystems we haven't discovered, the sounds we haven't identified,
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some of it is disappearing before we ever find it.
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We are writing an ending to a story we never read the beginning of.
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Back to the beach.
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You're standing at the edge of the water.
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Same place you started.
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The ocean in front of you looks the same as it did at the beginning.
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Waves.
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Horizon.
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All that blue.
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But you know now what blue means.
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It means pressure that would collapse your lungs in seconds.
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It means creatures the size of buses that lived their entire evolutionary history without us knowing.
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It means ecosystems that don't need the sun.
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It means sounds we recorded and still can't fully explain.
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It means 3 million shipwrecks and an unknown number of species
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and an entire volume of the planet that we have in 300 ,000 years of human existence, barely touched.
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95 % of the ocean is still out there, in the dark, doing whatever it does, whether we ever see it or not.
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Vocabulary and speaking notes for this lesson
This speaking lesson is built on the video “Why Almost All of the Ocean is Still Unexplored?”. The speaker keeps coming back to these words: ocean, meter, deep, pressure, sound. This video has 225 sentences and 2205 words to shadow. The speech runs for 11:41. The speaker talks fast, about 189 words per minute, so expect linked and reduced sounds. 82% of the words are among the 3,000 most common in English; the rest is worth studying before you start.
Key vocabulary in this video
15 words from the video worth learning, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| meter noun | /ˈmitəɹ/ | A device that measures things. |
| darkness noun | /ˈdɑɹk.nɪs/ | The state of being dark; lack of light; the absolute or comparative absence of light. |
| ecosystem noun | /ˈikoʊˌsɪstəm/ | A system formed by an ecological community and its environment that functions as a unit. |
| whale noun | /ˈweɪl/ | Any large cetacean, usually with the exclusion of dolphins and porpoises. |
| underwater adjective | /ʌndɚˈwɔtəɹ/ | Beneath the surface of the water; of or pertaining to the region beneath the water surface. |
| vent noun | /vɛnt/ | An opening through which gases, especially air, can pass. |
| vessel noun | /ˈvɛsəl/ | Any craft designed for transportation on or in water, such as a ship, boat, or submarine. |
| layer noun | /ˈleɪ̯ɚ/ | A single thickness of some material covering a surface. |
| biological adjective | /ˌbaɪ.əˈlɑ.d͡ʒɪ.kəl/ | Of or relating to biology. |
| explore verb | /ɪkˈsploɹ/ | To examine or investigate something systematically. |
| sink verb | /ˈsɪŋk/ | To descend or submerge (or to cause to do so) into a liquid or similar substance. |
| researcher noun | /ˈɹiˌsɝ.t͡ʃɚ/ | One who researches. |
| sunlight noun | /ˈsʌnˌlaɪt/ | All the electromagnetic radiation given off by the Sun; especially, that in the visible spectrum and that bathes the Earth. |
| explanation noun | /ˌɛkspləˈneɪʃən/ | The act or process of explaining. |
| essentially adverb | /ɪˈsɛnʃəli/ | In essence: by nature. |
Phrasal verbs you will hear
| Word | Pronunciation | Meaning |
|---|---|---|
| rule out verb | To cross an item out by drawing a straight line through it, as with a ruler. | |
| back up verb | To move backwards, especially for a vehicle to do so. | |
| come out verb | /ˌkʌm ˈaʊt/ | To be discovered; to be revealed. |
| cut through verb | To take a shortcut through. | |
| pick up verb | To lift; to grasp and raise. | |
| send back verb | To return (something) to its origin. |
Sentences worth repeating
Short, complete lines from the video that you can reuse in everyday conversation:
- Every person you've ever met.
- That's the part we know.
- This is the part we've explored.
- If we're missing whales, what else are we missing?
- How many more ecosystems we've never seen?
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Present perfect have/has + past participle — a past action that still matters now | you've ever met · has ever been seen · have sent |
| Passive voice be + past participle — the focus is on what happens, not who does it | isn't covered · been seen · is built |
Pronunciation to watch
The speaker uses 38 contractions and reduced forms, such as haven't, we've, don't. Say them the short way, as you hear them.
- The “th” sounds: bother /ˈbɑðɚ/, beneath /bɪˈniːθ/, earthquake /ˈɝθkweɪk/, myth /mɪθ/, withstand /wɪðˈstænd/
- The “sh” and “zh” sounds: explanation /ˌɛkspləˈneɪʃən/, essentially /ɪˈsɛnʃəli/, crush /kɹʌʃ/, evolutionary /ˌiː.vəˈluː.ʃən.ɛɹ.i/, capture /ˈkæp.(t)ʃɚ/
- Long words — get the stress right: ecosystem /ˈikoʊˌsɪstəm/, underwater /ʌndɚˈwɔtəɹ/, biological /ˌbaɪ.əˈlɑ.d͡ʒɪ.kəl/, explanation /ˌɛkspləˈneɪʃən/, essentially /ɪˈsɛnʃəli/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like meter, darkness, ecosystem.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.