Many animals live in extreme environments, including camels. A camel's two humps store fat as a source of energy in a barren, desert climate. The desert is one example of an extreme environment.
Extreme environments are habitats where most life, including humans, cannot thrive or survive. These harsh areas might have extreme temperatures, exceptionally high pressures or high acidity.
For quite some time, experts thought that extreme environments could not sustain life. Although most organisms cannot live in such places, some organisms—known as extremophiles—have adapted to such conditions.
An environment is extremely acidic when conditions are less than 5 on the pH scale. Essentially, pH levels indicate how acidic, neutral, or basic (alkaline) something is. A level of 1 is extremely acidic and a level of 14 is extremely basic. The optimal pH level for a human is around 7.35 to 7.45—slightly basic.
Extremely Acidic or Basic Environments
Extremely acidic habitats are found around the world. They can be natural or human-made. Volcanic and geothermal areas, such as hot springs, accumulate large amounts of sulfuric acid. The acid produces particularly low pH ecosystems. The Rio Tinto, a river in Spain—known for its deep-red waters—and geothermal sites in the United States' Yellowstone National Park are two examples of such environments.
Acidophiles are creatures that can live in acidic environments with pH values ranging from 1 to 5. One acidophile is Cyanidium caldarium, a type of red algae. For most animals, high acid levels destroy or damage their cells, but this is not the case for acidophiles. They have adapted ways to preserve the internal pH levels of their cells at around 7; this is a neutral pH.
Acidophiles can possibly help humans and other living things since they can be purposely introduced into an environment to break down some toxic contaminants.
The opposite of extreme acidic environments is basic, or alkaline, environments. These natural habitats feature a pH level of 9 and above, and are found worldwide in areas with a high geothermic or volcanic activity, such as Yellowstone National Park's hot springs and the Great Rift Valley in northeastern Africa.
In many places around the world, temperatures are mild. But other areas are extremely hot or extremely cold.
Frigid, dry environments, such as those found in polar regions, are extreme habitats that consistently reach temperatures below 5 degrees Celsius (41 degrees Fahrenheit). Scientists have discovered that microbes can survive and live well in various cold regions. In 2013, a team of scientists found a bacteria that consumes methane under the ice in Antarctica. These bacteria are a type of psychrophile, meaning they are microorganisms that grow best at temperatures of 15 degrees Celsius (55 degrees Fahrenheit) and below.
Some of the most extreme habitats boast temperatures of more than 40 degrees Celsius (104 degrees Fahrenheit). Many of these sites include deep-sea vents and hot springs. Thomas Brock, an American microbiologist, discovered microorganisms surviving and even growing in Yellowstone's scalding hot springs in 1966. Since then, thermopiles—organisms that love heat—have been found all over the world in hot springs and geysers.
Deserts are also considered to be extreme, hot environments and animals, such as the sidewinder snake, have learned to survive there. They have developed a way to slither across the hot sand so that only parts of their bodies touch the hot sand at once—not moving lengthwise. This technique limits the amount of body exposed to the burning sand.
What Can We Learn from Extreme Environments on Earth?
The living things that have learned to flourish in such harsh habitats can provide answers to important questions. Take Alaska's wood frogs (Lithobates sylvaticus), for example. These amphibians freeze when winter arrives in Alaska, but once spring appears many months later, the frogs thaw and continue on with their lives.
How can this be? Scientists have discovered that the frogs produce chemicals that prevent ice crystals from forming—an event that would pierce the frogs' cells and organs. By studying this species and its unique adaptation, scientists hope to discover a way to successfully store human organs for an extended amount of time to save for future transplantations. Currently, organs cannot last longer than a few hours when refrigerated; they are destroyed when frozen.
The tiny tardigrade, also known as the water bear, can survive in many different kinds of extreme environments. This includes the high altitudes of Asia's Himalaya, the intense pressure of the deep ocean, the frigid temperatures of Antarctica, and a 10-day journey to space. This microscopic organism could potentially help us learn more about what kinds of organisms could live on planets with extreme environments like Mars.