Many living things cannot survive in extreme environments. These are habitats that are unfriendly to most organisms.

Sometimes, these habitats are extremely hot or cold. Others might be too acidic. Only special organisms called extremophiles can live in these conditions.

How Does Acid Affect Environments?

Acids are chemical substances. You can find strong acids in many parts of the world. Some are made by nature. Others are made by humans.

Acidity is measured on something called a pH scale. The scale ranges from 1 to 14. A level of 1 is very acidic. A level of 14 is very basic.

Some environments are very acidic. In these environments, conditions are less than 5 on the pH scale. For example, areas near volcanoes can be very acidic. These habitats have large amounts of sulfuric acid. This is a dangerous chemical.

High acid levels destroy many plants and animals. But some organisms can survive in acid. They are called acidophiles. One acidophile is a type of red algae. It does well in an acidic environment.

Basic Environments

The opposite of an acidic environment is a basic environment. It is also known as an alkaline environment. These habitats have a pH level higher than 9. They are also found in areas with high volcanic activity. Some are found in hot springs. The hot springs of the United States' Yellowstone National Park are home to some extremely basic environments.

Some places on Earth are extremely cold and dry. Some of these habitats continuously reach temperatures below 5 degrees Celsius (41 degrees Fahrenheit). Think of the South Pole. Not many organisms can survive there. But some bacteria can survive there. Some even live under the ice.

Superhot Environments

Other extreme habitats are very hot. Some reach temperatures of more than 40 degrees Celsius (104 degrees Fahrenheit). Examples of very hot environments are deep-sea vents and hot springs. Some organisms can live in these places. They are very tiny organisms called thermophiles.

What Can We Learn from Extreme Environments on Earth?

Scientists can learn a lot from animals that live in extreme places. Take wood frogs (Lithobates sylvaticus), for example. They live in U.S. state of Alaska. When winter approaches, the frogs freeze. But in spring, they thaw, or defrost. Then they carry on with their lives.

How does this happen? The frogs produce chemicals. These chemicals prevent ice from forming in their bodies. This means that their hearts do not freeze. Scientists want to use this information to help people. They hope to successfully store human organs, like hearts, for long periods of time. Organs have to be kept cold. They cannot last longer than a few hours when refrigerated. Studying the frogs could help scientists learn to save organs for longer periods of time.

Another extremophile is the tardigrade or water bear. It is very tiny. It can live in many different extreme places. Some have lived on tall mountains. Some have lived deep in the ocean. Water bears even survived in space for 10 days. Tardigrades could help scientists to understand how to live on Mars.