Extremophiles are bacteria of a group called archaea, and they live and thrive in harsh environments. These bacteria were discovered in the 1970’s in places such as Yellowstone National Park and around hydrothermal vents on the ocean floor. Their discovery has greatly influenced the biotechnology industry and spurred the belief in life on other planets. On Earth there are several environments that support only extremophilic bacteria.
As of 2003, more than 50 species of thermophiles had been discovered. This bacteria survives in conditions of extreme heat; it can withstand water temperatures over 93.3 degrees Celsius and requires a temperature over 90 degrees Celsius to survive. Thermophiles prevent the dissolution of cell wall constituents and genetic material at extremely high temperatures.
Halophilic bacteria thrive in an environment of extremely concentrated sodium, such as the Dead Sea or the Great Salt Lake. These bacteria can only survive in potassium chloride-rich environments.
Acidophiles are found in highly acidic environments, where the pH level is below 5. At the opposite end of the spectrum, highly alkaline bacteria require a pH above 9. Extremely acidic bacteria are found in the runoff of mine drainage where the pH is below 1, more acidic than stomach acid.
The term anaerobic means in the absence of oxygen. Anaerobophiles die if any oxygen is present in their environments. One example of an anaerobic environment is the intestinal tract.
Psychophiles thrive in the extremely low temperatures of ocean water, permafrost and polar ice. These bacteria contain special proteins that act as antifreeze.
Barophile bacteria survive in extremely high gas or liquid pressure. These organisms live over 7,000 feet below the surface of the ocean, where pressure exceeds 1433 Kilogram per square inch. Extremely low pressure extremophiles can be found in clouds.
Radioresistant extremophiles survive very high levels of radiation, over 1,000 times greater than a human cell can withstand. These bacteria are able to repair genetic mutations caused by radiation very quickly by disassembling mutated genetic sequences and putting them back together in proper sequence.