What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys
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0:07 - 0:10What's so great about the Great Lakes?
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0:10 - 0:14They're known as America's inland seas.
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0:14 - 0:15The North American Great Lakes
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0:15 - 0:16Huron,
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0:16 - 0:17Ontario,
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0:17 - 0:18Michigan,
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0:18 - 0:18Erie,
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0:18 - 0:19and Superior
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0:19 - 0:22are so massive
that they border eight states -
0:22 - 0:26and contain 23 quadrillion
liters of water. -
0:26 - 0:30That's enough to cover the land area
of the contiguous United States -
0:30 - 0:32three meters deep.
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0:32 - 0:34These vast bodies of water span forest,
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0:34 - 0:35grassland,
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0:35 - 0:36and wetland habitats,
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0:36 - 0:41supporting a region that's home to over
3,500 species. -
0:41 - 0:45But how did such a vast and unique
geological feature come to be? -
0:45 - 0:50The story begins near the end
of the last ice age over 10,000 years ago, -
0:50 - 0:52a time when the climate was warming
-
0:52 - 0:56and the glaciers that cloaked the Earth's
surface began their slow retreat. -
0:56 - 1:00These immense ice sheets carved out
a series of basins. -
1:00 - 1:03Those basins filled with water
as the ice began to melt, -
1:03 - 1:07creating the world's largest area
of freshwater lakes. -
1:07 - 1:10Over time, channels developed between
these basins, -
1:10 - 1:13and water began to flow in
an ongoing exchange -
1:13 - 1:15that persists to this day.
-
1:15 - 1:18In fact, today,
the interconnected Great Lakes -
1:18 - 1:23contain almost 20% of the world's supply
of fresh surface water. -
1:23 - 1:27The water's journey begins in
the far north of Lake Superior, -
1:27 - 1:30which is the deepest, coldest,
and clearest of the lakes, -
1:30 - 1:33containing half the system's water.
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1:33 - 1:37Lake Superior sinks to depths
of 406 meters, -
1:37 - 1:42creating a unique and diverse ecosystem
that includes more that 80 fish species. -
1:42 - 1:47A given drop of water spends on average
200 years in this lake -
1:47 - 1:50before flowing into Lake Michigan
or Lake Huron. -
1:50 - 1:55Linked by the Straits of Mackinac,
these two lakes are technically one. -
1:55 - 1:57To the west lies Lake Michigan,
-
1:57 - 2:00the third largest of the lakes
by surface area. -
2:00 - 2:03Water slowly moves through
its cul-de-sac shape -
2:03 - 2:06and encounters the world's largest
freshwater dunes, -
2:06 - 2:07many wildlife species,
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2:07 - 2:09and unique fossilized coral.
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2:09 - 2:13To the east is Lake Huron,
which has the longest shoreline. -
2:13 - 2:16It's sparsely populated,
but heavily forested, -
2:16 - 2:19including 7,000-year-old petrified trees.
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2:19 - 2:23Below them, water continues to flow
southeastwards -
2:23 - 2:25from Lake Huron into Lake Erie.
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2:25 - 2:29This lake's status as the warmest
and shallowest of the five -
2:29 - 2:34has ensured an abundance of animal life,
including millions of migrating birds. -
2:34 - 2:38Finally, the water reaches its last stop
by dramatically plunging -
2:38 - 2:42more than 50 meters down
the thundering Niagara Falls -
2:42 - 2:45into Lake Ontario, the smallest lake
by surface area. -
2:45 - 2:50From there, some of this well-traveled
water enters the St. Lawrence River, -
2:50 - 2:52eventually reaching the Atlantic Ocean.
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2:52 - 2:54In addition to being a natural wonder,
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2:54 - 2:58the perpetually flowing Great Lakes
bring us multiple benefits. -
2:58 - 3:00They provide natural water filtration,
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3:00 - 3:01flood control,
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3:01 - 3:03and nutrients cycling.
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3:03 - 3:06By moving water across
more than 3,200 kilometers, -
3:06 - 3:11the Great Lakes also provide drinking
water for upward of 40 million people -
3:11 - 3:15and 212 billion liters a day
for the industries and farms -
3:15 - 3:17that line their banks.
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3:17 - 3:21But our dependence on the system is
having a range of negative impacts, too. -
3:21 - 3:26The Great Lakes coastal habitats are being
degraded and increasingly populated, -
3:26 - 3:27exposing the once pristine waters
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3:27 - 3:31to industrial, urban,
and agricultural pollutants. -
3:31 - 3:35Because less than 1% of the water
leaves the Lake's system annually, -
3:35 - 3:38decades-old pollutants still lurk
in its waters. -
3:38 - 3:40Humans have also inadvertently introduced
-
3:40 - 3:45more than 100 non-native
and invasive species into the lakes, -
3:45 - 3:49such as zebra and quagga mussels,
and sea lampreys -
3:49 - 3:52that have decimated some indigenous
fish populations. -
3:52 - 3:55On a larger scale, climate change
is causing the waters to warm, -
3:55 - 4:00thus reducing water levels and changing
the distribution of aquatic life. -
4:00 - 4:04Luckily, in recent years, governments have
started to recognize the immense value -
4:04 - 4:06of this natural resource.
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4:06 - 4:10Partnerships between the United States and
Canada are underway to reduce pollution, -
4:10 - 4:12protect coastal habitats,
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4:12 - 4:15and halt the spread of invasive species.
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4:15 - 4:18Protecting something as massive
as the Great Lakes system -
4:18 - 4:21will require the collaboration
of many organizations, -
4:21 - 4:22but the effort is critical
-
4:22 - 4:26if we can preserve the wonder
of this flowing inland sea.
- Title:
- What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys
- Description:
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View full lesson: http://ed.ted.com/lessons/what-s-so-great-about-the-great-lakes-cheri-dobbs-and-jennifer-gabrys
The North American Great Lakes — Huron, Ontario, Michigan, Erie, and Superior — are so big that they border 8 states and contain 23 quadrillion liters of water. They span forest, grassland, and wetland habitats, supporting a region that’s home to 3,500 species. But how did such a vast and unique geological feature come to be? Cheri Dobbs and Jennifer Gabrys takes us all the way back to the Ice Age to find out.
Lesson by Cheri Dobbs and Jennifer Gabrys, animation by TED-Ed.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:52
Krystian Aparta commented on English subtitles for What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys | ||
Krystian Aparta edited English subtitles for What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys | ||
Jessica Ruby approved English subtitles for What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys | ||
Jessica Ruby accepted English subtitles for What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys | ||
Jessica Ruby edited English subtitles for What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys | ||
Jennifer Cody edited English subtitles for What’s so great about the Great Lakes? - Cheri Dobbs and Jennifer Gabrys |
Krystian Aparta
The English transcript was updated on 3/17/2017 to reflect changes in the video.