This is an aerial view of Grand Prismatic hot spring in Yellowstone National Park, USA. Several types of microbes thrive in the extreme environments of hot springs like this one. Some organisms even prosper in highly acidic hot springs! The rainbow hues of some hot springs are produced by various colors of microbes that live in different temperature niches within each spring. Click on image for full size (114 Kb) Image courtesy of the US Natl. Park Service, photograph by Al Mebane.

This page describes extreme environments that are acidic or alkaline, are exposed to high levels of radiation, are under tremendous pressure, or are hostile to "normal" life in a number of other unusual ways. Extreme environments are places that are inhospitable to most "normal" living creatures. Extreme environments are not necessarily lifeless. Certain types of organisms, known collectively as "extremophiles", have adapted to survive or even thrive in various types of extreme environments.

Familiar extreme environments include deserts, mountain peaks, caves, and the frozen realms of the Arctic and Antarctic. Some extreme environments are very hot or very cold, extremely dry, or both.

Several types of chemicals present in certain environments push life to the brink and beyond. Places like Utah's (USA) Great Salt Lake and the aptly-named Dead Sea in the Middle East are typical hyper-saline (extremely salty) environments in which only specially adapted creatures can live. Other organisms manage to get by in extremely acidic or alkaline environments. Some hot springs and places where polluting chemicals seep from mines are typical acidic environments, with a pH of 3 or less, in which specialized microbes survive.

Some environments have high levels of radiation. High-altitude mountaintops, which jut above much of Earth's protective atmosphere, suffer increased levels of ultraviolet (UV) radiation exposure. Caves and other underground voids, as well as human-created waste dumps, can contain radioactive materials that bombard nearby creatures. Some microbes live in microscopic pores inside of rocks or within fissures deep beneath Earth's surface.

Certain environments, usually far underground or deep beneath the ocean, have high pressures that are hard for most creatures to handle. Many niches are extremely poor in nutrients, depriving their inhabitants of food sources. Others lack oxygen, making them off-limits to "air breathers" like ourselves. Places such as caves and the deep ocean are perpetually dark, so photosynthetic organisms that form the basis of many food webs cannot grow there for lack of sunlight.

This is an aerial view of a hot spring in Yellowstone National Park, USA. This large pool is called Grand Prismatic hot spring. Hot springs are an extreme environment, but some kinds of microbes can live in them. The water in some hot springs is strongly acidic, but some microbes manage to live in those, too. Different kinds of microbes have different colors. The colored microbes make this spring look like a rainbow! Click on image for full size (114 Kb) Image courtesy of the US Natl. Park Service, photograph by Al Mebane.

This page describes extreme environments that are filled with acids, are blasted with radiation, are under high pressure, or are tough places for most living things in various other ways. Extreme environments are places where "normal" life finds it hard to survive. That doesn't mean that there isn't any life in extreme environments. Certain creatures can live and grow in extreme environments. Scientists have a special name for creatures that live in extreme environments. They are called "extremophiles".

What kinds of environments are "extreme"? Some extreme environments that you may know about are deserts, mountain peaks, caves, and frozen places like the Arctic and Antarctic. Some environments are very hot or very cold, extremely dry, or both.

Poisonous chemicals in some environments are deadly to most creatures. Some environments have lots and lots of salt, which dries out and kills most living things. The Dead Sea in the Middle East and Utah's (USA) Great Salt Lake are examples of bodies of water that are much, much saltier than the oceans. Some environments have high levels of acids or bases, which tend to kill most creatures. Water seeping through old mines can turn to acid. Some hot springs are also acidic, and only special types of microbes can live there.

Some environments have lots of radiation. The tops of high mountains stick up above most of Earth's atmosphere. High places get hit with ultraviolet (UV) radiation from the Sun. Caves and other places underground, as well as waste dumps created by humans, can have radioactive materials that bombard nearby creatures. There are other sorts of extreme environments in cracks in rocks underground and even inside tiny spaces within rocks.

High pressures make some environments extreme. Places far underground or deep beneath the ocean have high pressures that are deadly to most, but not all, creatures. Some environments have almost no food, making them extreme. Other places don't have oxygen, so creatures like us who need to breathe it cannot survive there. Caves and the deep ocean are always dark, so plants and other creatures that make food using photosynthesis (and other creatures that feed on them) can't live there.

This is an aerial view of a hot spring in Yellowstone National Park, USA. This large pool is called Grand Prismatic hot spring. Hot springs are an extreme environment, but some kinds of microbes can live in them. The water in some hot springs is a strong acid, but some microbes manage to live in those, too. Different kinds of microbes have different colors. The colored microbes make this spring look like a rainbow! Click on image for full size (114 Kb) Image courtesy of the US Natl. Park Service, photograph by Al Mebane.

This page describes environments that are filled with acids, are blasted with radiation, are under high pressure, or are tough places for most living things in other ways. It is easy for living creatures to survive and grow in some places. Other places make it tough for life to get by. Scientists call places that are hard on life "extreme environments".

What kinds of places are "extreme environments"? Some that you may know about are deserts, mountain peaks, caves, and frozen places like the Arctic and Antarctic. Some environments are very hot or very cold, really dry, or both.

Just because an environment is extreme doesn't mean there is no life there. Certain creatures can live and grow in extreme environments. Scientists have a special name for creatures that live in extreme environments. They are called "extremophiles".

Poisonous chemicals in some environments are deadly to most creatures. Some environments have lots and lots of salt, which dries out and kills most living things. Some environments have high levels of acids that kill most creatures. Water seeping through old mines can turn into acid. Some hot springs are also acidic, and only special types of microbes can live there.

Some environments have lots of radiation. The tops of high mountains stick up above most of Earth's atmosphere. High places get hit with ultraviolet (UV) radiation from the Sun. Some waste dumps created by humans have radioactive materials. Natural sources of radiation can also be found in caves and other places underground. There are other sorts of extreme environments in cracks in rocks underground and even inside tiny spaces within rocks.

High pressures make some environments extreme. Places far underground or deep beneath the ocean have high pressures that are deadly to most creatures. Some environments have almost no food, making them extreme. Other places don't have oxygen, so creatures like us who need to breathe it cannot survive there. Caves and the deep ocean are always dark. Plants and other creatures that make food using photosynthesis can't live there.