Polar

polar

Polar ecosystems include both land and water. cloudzilla via Compfight cc

As you might guess, polar ecosystems are closest to the earth’s poles , or the top and bottom of our planet. These are the coldest places in the world – the lowest temperature ever recorded on Earth was in Antarctica, where it reached more than 128 degrees below zero!

Some polar regions are snowy and icy all year round, like most of Antarctica. Other polar areas are covered in soil, but since the ground tends to stay frozen, it’s hard for plants and animals to make a living.

land

All polar habitats are cold year-round, but they aren’t always covered with snow. Source: Wikimedia

There’s plenty of water here too – both the Arctic Ocean and the Southern Ocean are part of the polar ecosystem.

Despite their chilly challenges, polar habitats have a surprisingly large number of species , ranging from tiny mosses to big animals like reindeer and polar bears.

Adaptations

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Most polar plants are small and grow close to the ground. Royal Olive via Compfight cc

Thanks to freezing-cold weather and scarce sunlight, polar ecosystems can be a tough place for plants and animals to survive. But each species there has evolved adaptations to deal with this challenging habitat.

Polar plants, for example, grow close to the ground and never get too tall, which helps them avoid the cold wind. That’s why you won’t find many tall trees in polar habitats – it’s much warmer closer to the ground.

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An arctic tern. Source: Wikimedia

One way polar animals stay warm is by building up a thick layer of fat – called blubber – that protects them from the cold air and water. Polar bears, walruses, and whales all have blubber that is several inches thick.

Other animals simply leave their polar home when it gets too cold. Many birds perform this kind of disappearing act, migrating to warmer climates during the dark and chilly winter months. The arctic tern has the longest known migration in the world, travelling more than 40,000 miles each year. During its lifetime, an arctic tern can travel the same distance as three trips to the moon and back!

Interactions

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Krill are a food source for many polar animals. Source: Wikimedia

Because of the challenging climate , food can be hard to find in polar ecosystems. Animals must compete for their meals. Sometimes, this competition is a head-to-head battle. For example, grizzly bears fight over salmon in the rivers, and the biggest and meanest bear usually wins the meal.

But competition isn’t always between members of the same species – often, many different animals compete for the same food. In the Arctic Ocean lives a small shrimp-like creature called krill. Nearly every ocean-dweller loves to eat krill, which means that these animals are all competing for the same food source. But there’s never enough to go around.

Penguins, for example, feast on tiny krill for most of the year. But when whales migrate to the cold polar regions in the winter months, these big creatures eat all the krill and drive the penguins away. The penguins must switch to eating fish until the whales leave, and then they can return to their diet of delicious krill.

Challenges

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A polar iceberg serves as a resting spot for penguins. nick_russill via Compfight cc

The biggest threat to the polar ecosystem is climate change , because it is warming up these unique habitats. In some polar regions, the average temperature has risen by more than 7 degrees (F) in the last 100 years!

Animals that live in polar habitats are specialized to live in very chilly climates, and they might not be able to survive as the weather gets warmer. Animals with plenty of blubber, for example, can overheat as temperatures rise.

Higher temperatures can cause other problems for polar species by melting the ice and snow. Animals like polar bears and penguins rely on floating icebergs as places to rest and hunt as they cross the cold oceans. Plus, melting icebergs makes the sea level rise, which puts all life on the planet – even us! – in danger.

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