00:00A hole about the size of Switzerland or South Carolina keeps popping up in the Antarctic
00:06eyes. This opening is growing steadily, and it took scientists half a century to figure
00:11out why. They found the answer with the help of seals.
00:16The scientists first spotted this gap, called Maud-rise-polyneia, in the Weddell Sea in
00:221974. They were about to close the case as the hole disappeared, but it popped out again
00:28in the following two years, and then only in 2016.
00:33The giant hole is near Maud-rise, an underwater mountain. This type of hole is a polyneia,
00:39a rare patch of open water surrounded by thick sea ice. In Antarctica, when winter hits, the
00:45ocean's surface freezes, and sea ice spreads out to cover an area about twice as big as
00:51the continental United States. Along the coast, openings in the sea ice pop up every year.
00:57This happens when powerful coastal winds blow off the continent and push the ice away.
01:03But it's a whole lot rarer for these openings to form way out over the open ocean, hundreds
01:08of miles from land, where the water is thousands of feet deep.
01:13Researchers from several universities teamed up to study the Maud-rise-polyneia using computer
01:19models and satellite images. They even recruited some Antarctic seals to help out. These seals
01:25wore tiny helmets on their furry round heads with tracker sensors attached to them. Thanks
01:31to these science-y seals, the team could collect water data from the source.
01:36After the research, the scientists discovered that the hole resulted from a complex mix of
01:42factors. The wind, ocean currents, and the special shape of the ocean floor all work together,
01:48cooling heat and salt up to the surface. In science talk, this swirling movement is called
01:54an Ekman transport. Ekman transport is what happens when wind messes with the surface of
02:00the ocean. When the wind blows across the water, it creates friction that grabs onto the top layer
02:06and pulls it along. Thanks to the Coriolis effect, which comes from Earth's spinning, the moving water
02:12gets pushed at a 90-degree angle from the wind's direction. So instead of the water going exactly
02:18where the wind is pushing it, it drifts off at an angle. Which way it turns depends on which
02:24half of the planet you're on. In the Northern Hemisphere, the water shifts clockwise from the
02:29wind direction. And in the Southern Hemisphere, it shifts counterclockwise.
02:35Ekman transport turned out to be the missing piece of the puzzle in the case of the Maud-rise-hole.
02:41It helped balance the salt levels and keep mixing salt and heat up to the ocean surface.
02:46But as the sea ice melts, the surface water becomes less salty, which should stop the mixing.
02:52So the scientists realized something else had to be happening to keep the Polyneia open.
02:59There had to be another source of salt. Salt lowers the freezing point of water. To find
03:04out where this extra salt was coming from, the team dug back into their data and ran more
03:10computer models on the ocean. They found that swirling currents formed as the Waddell current
03:15flows around Maud-rise. These currents carry salt up to the top of the underwater mountain.
03:21From there, Ekman transport kicks in. As the top layer of water moves away with the wind,
03:28water from deeper down rises to take its place. At Maud-rise, this upwelling water brings along
03:34the extra salty water build up around the seamount. And that's what helps keep the Polyneia from
03:40freezing over. Scientists follow any changes in Antarctica as they influence the rest of the world.
03:48Researchers at Stanford University used machine learning for the first time to study detailed
03:53satellite data, showing how ice moves in the polar region. They combined huge amounts of real-world data
04:00with physics rules to understand the Antarctic ice sheet better. It's the biggest ice mass on Earth,
04:06almost twice as large as Australia. It acts like a giant sponge for the planet, storing fresh water
04:13as ice and stabilizing sea levels. Scientists used to rely on models based on lab experiments,
04:19but real Antarctic ice is way more complex, with cracks, air pockets, and different types of ice
04:26that behave unpredictably. Instead of trying to model every little detail, the team trained a
04:32machine learning model using data from 2007 to 2018. It looked at five major ice shelves,
04:40and created new models showing the ice's resistance to flow. They found that near the land,
04:46the ice is compressed and behaves as in lab predictions. But farther out, the ice is stretched
04:53toward the ocean, and acts differently depending on direction. Less than 5% of the ice shelf is
04:59compressed. The other 95% behaves in a way old models didn't fully explain. This research could
05:06seriously improve our predictions of how Antarctica might change in the future.
05:11Another recent piece of big scientific news from Antarctica changes the history of birds as we know it.
05:18For a long time, it was simple. Dinosaurs ruled the Earth until an asteroid hit 66 million years ago
05:25and wiped them all out. Except for some avian dinosaurs, which eventually became birds like
05:31eagles and chickens. Now, scientists have found a headless fossil of a VYI on Vega Island in Antarctica.
05:40The fossil was 68 million years old, at least 2 million years older than the asteroid strike.
05:46Without a skull, it was unclear what modern birds VYI might be related to, and guesses included waterfowl and
05:55shorebirds. Nearly 20 years later, another expedition found a bird's skull in Antarctica. After careful
06:02study, scientists matched it to VYI and concluded it was an ancestor of modern water birds like loons and
06:10grebes. If it's all true, VYI is now the oldest known modern bird in fossil records. The skull had a long
06:18pointed beak, a brain unlike any other Mesozoic bird, and signs of strong jaw muscles like mine, which were
06:26perfect for diving underwater and catching fish. The body fossil also had adaptations for underwater
06:33swimming, similar to modern diving birds. During the late Cretaceous period, Antarctica was a temperate
06:40rainforest far from the Yucatan, so it could have become a safe haven during the asteroid disaster.
06:47So early modern birds might have survived there.
06:51When a giant iceberg, about the size of Chicago, broke off from Antarctica's massive ice shelf, scientists
06:58nearby did something no one had ever done before. They sailed straight over to check out the newly
07:05exposed sea floor. Studying the undersides of ice shelves is incredibly hard, but thanks to the
07:12iceberg A84, a 209-square-mile patch of sea floor suddenly opened wide for exploration. The scientists
07:21deployed all their high-tech gear, including a remotely operated submersible and autonomous robots,
07:27to collect data about the sea floor and the properties of the water above it.
07:32Life exists almost everywhere in the ocean, from the bright, shallow waters to the pitch-black,
07:38volcanic deep sea. But the research team was really surprised to find such a diversity of life down
07:45there. They found a forest of sponges, giant sea spiders, ice fish, octopuses, huge corals,
07:53anemones, and even glowing deep-sea jellyfish. Normally, deep-sea creatures get their nutrients
07:59from organic matter falling from the ocean surface. But under a 500-foot-thick sheet of ice that had
08:06been there for who knows how long, that wasn't possible. That meant the creatures had to be getting
08:12their nutrients in some completely different way. To figure out how long this hidden ecosystem had been
08:18around, the scientists studied the sea sponges. Sponges grow extremely slowly, only about an inch
08:25per year. But the ones they found were huge, so they must have been growing there for decades
08:31or even centuries. The team is hoping that the mountain of ocean and environmental data they
08:36collected during the expedition will help them understand how these ecosystems managed to thrive
08:41in those conditions and maybe reveal some completely new species that no one has ever seen before.
08:48That's it for today. So hey, if you pacified your curiosity, then give the video a like and share it
08:54with your friends. Or if you want more, just click on these videos and stay on the Bright Side!
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