Scientists Say: Desert

These ecosystems aren’t always hot, but they are always dry

These cacti are growing in the Sonoran Desert in Arizona. They store water in their thick trunks under a waxy coating.

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Desert (noun, “DEH-zert”)

This is a type of ecosystem that is very, very dry. Deserts get very little precipitation, either rain or snow. A true desert gets less than 250 millimeters (10 inches) of precipitation per year.

Deserts have a reputation for being hot. However, they don’t have to be. Temperature doesn’t define a desert. The Sahara is a desert. So is Antarctica. Antarctica gets very little rain or snow, but it is so cold that its snow and ice tends not to melt.

Many deserts are so dry that few plants can grow there. Those that do have special adaptations, or features that help them survive. Some might have very long roots that reach deep down into the ground to get water. Others might have thick, spongy flesh that can store water for long periods of time. Animals and other organisms have evolved to feed off these plants. This results in desert ecosystems full of unique creatures — some of which can go their whole lives without ever taking a sip of water.

In a sentence

In the Atacama desert in Chile, lichen can live by getting water from fog in the air.

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Bethany Brookshire is the staff writer at Science News for Students. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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