How you survive the coldest place on Earth - Nadia Frontier

197,989 views ・ 2023-10-10

TED-Ed


Please double-click on the English subtitles below to play the video.

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The vast, white ice surface of Antarctica
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stretches for over 3 million square kilometers:
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empty, desolate, and almost completely silent.
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But appearances can be deceiving.
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On the coast of this expanse,
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just a few meters beneath the ice lies a multicolored constellation of life.
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This remarkably diverse realm is home to over 8,000 species of sea denizens
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who rely on an arsenal of otherworldly traits to survive.
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So how do these species not only live, but thrive,
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in conditions most animals would be unable to bear?
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Antarctic waters are some of the most consistently frigid in the world,
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hovering below 0 degrees Celsius for a large portion of the year.
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This means burning energy too quickly can be deadly,
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so survival in this ecosystem looks slow and steady.
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Freezing temperatures persist even in the summer,
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but this season brings a rare gift: sunlight.
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For a brief period, it’s abundant,
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shining through the ice for 24 hours a day.
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This infusion of energy drives intense coastal phytoplankton blooms,
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transforming the waters into a thick green soup.
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Marine life both large and small takes advantage of this bounty,
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including the giant Antarctic isopod.
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Cousins of the humble pill bug,
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these crustaceans can reach up to 11 centimeters long,
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and they never miss the opportunity for a meal.
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The scavengers eat a wide variety of prey, including other giant isopods.
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And by slowing their metabolisms, they can make this food last,
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with one study showing specimens surviving for 50 days without eating.
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Since this adaptation involves careful conservation of energy,
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giant isopods spend most of their time stationary or inching across the seafloor.
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Meanwhile, their tiny amphipod relatives celebrate the summer
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by releasing offspring alongside the algal explosion,
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ensuring their young have an abundance of food.
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And sea cucumbers carpeting the seafloor hoover up the dense plankton
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with outstretched tentacles,
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producing nutrient-rich feces that nourish nearby life.
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But this big summer blowout doesn’t last long.
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The first signs of autumn arrive in fine needles of frazil ice.
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These slowly coagulating crystals form a skin across the surface,
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then mix with falling snow before freezing into a thin crust of ice.
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The waters get darker and colder.
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And in this swiftly dimming world,
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a set of long, spiky limbs sidle into view.
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With up to six pairs of legs, these giant sea spiders aren’t arachnids,
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but rather a related class of marine arthropod unique to the seafloor.
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In addition to housing some of the animal’s organs,
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its legs are covered in tiny holes,
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which grow more numerous as the spider ages.
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These holes will likely help absorb the dissolved oxygen
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that saturates these freezing southern waters.
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Since oxygen fuels growth,
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many local species have evolved to take advantage of this abundance,
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and it may be one of the reasons that gigantism is so common in this region.
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Individual sea spiders, for instance, can grow to the size of dinner plates.
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But soon, these underwater giants will be moving slower than ever.
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As winter settles in, the sea floor becomes even colder.
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Waters fall to negative 1.8 degrees Celsius.
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On the surface, the thin icy crust thickens into a layer called nilas,
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and young sea ice starts forming ridges that block out the sun.
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The ocean begins to mirror the still landscape above it.
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Antarctic sea cucumbers and urchins go into dormancy for months,
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and their metabolic rates fall to the slowest on Earth.
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Antarctic limpets continue feeding,
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but at such a gradual pace that they're largely still surviving
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on energy reserves from the summer.
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Tiny crustaceans survive off the traces of algae
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growing on their home’s icy ceiling,
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raising their young in these expansive winter nurseries.
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But this seemingly endless winter won't last forever.
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As spring comes, light slowly begins to trickle back down through the ice.
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And week by week, bit by bit,
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this underwater world will begin waking up
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to begin its delicate, slow-motion dance once again.
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