Name: カナダ北部の凍結砂丘 (The Freezing Dunes of Northern Canada)
Uploaded: 2021-01-14T10:44:39.000Z
Duration: 6 min 13 s
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But the northernmost parts of Alberta and Saskatchewan in Canada

And yet here, at a latitude of fifty-nine [59] degrees,

They're one of the world's northernmost dune fields,

and one of planet Earth's most unique habitats.

a large expanse of nearly exposed bedrock.

The Shield formed during past periods of glaciation,

what is now Canada and parts of the United States.

This ice basically scraped everything down to that bedrock.

The dunes themselves date to the end of Earth's last glacial period,

These ice sheets were mind-bogglingly thick --

comparable modern ice sheets like Greenland's can be three kilometers deep.

And although we think of glaciers as just kind of sitting there,

and by material, I mean stuff like mountains --

gets pulverized down into what's called till.

As the planet warmed and the glaciers retreated north,

much of that till was carried along for the ride.

Think about how much water must've been produced

by the melting of a kilometer-thick ice sheet the size of Canada.

that flood dumped a big deposit of till into a massive lake.

it left behind what we now know of as the Athabasca dunes.

and created powerful winds that blew in a southeasterly direction.

This cool, dry air was key to slowing the growth of plants

that otherwise would have stabilized the sand with their root systems.

As the sand blew around, it didn't just pile up into nice, floofy mounds.

that somehow survived being crushed by the ice.

and broke it all down into smaller and smaller bits.

that the winds shifted to a more northerly angle, where they remain today.

But by that point, there was already a lot of sand.

Today, individual dunes can rise thirty 30 meters high

and stretch for up to a kilometer and a half in length.

there's a bunch of interesting life, too.

has allowed for the development of an ecosystem

that's pretty unlike what you'd find in a desert.

There are quite a few rare forms of life found here,

and a concentration of specialist species

which means they're not found anywhere else on the planet.

None of them are giant worms, unfortunately.

and they've evolved a number of adaptations

to the unusual and shifting conditions of the dunes.

to withstand the constant abrasion of windborne sand.

Many grow especially quickly to help avoid being buried under a shifting dune.

And if that doesn't work, some grow rhizomes,

which are secondary stems that sprout from the root system.

Perhaps the rarest of these species is the Athabasca Thrift.

it makes its home on a compacted layer of pebbles

Another rare species is the Large-headed Woolly Yarrow.

the name refers to the tiny hairs that cover its stem

and help the yarrow retain precious moisture against the relentless wind.

grows up to four meters tall to peek above the shifting sands.

If one of its thin, flexible branches does get buried,

it can become the start of a root system for a new,

help the wind carry them to new locations.

the Athabasca dunes are actually pretty well protected.

They fall largely within Saskatchewan's Athabasca Sand Dunes Provincial Park,

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