An overview of the world of microbes!
Archaea can be spherical, rod, spiral, lobed, rectangular or irregular in shape. An unusual flat, square-shaped species that lives in salty pools has also been discovered. Some exist as single cells, others form filaments or clusters. Until the 1970s this group of microbes was classified as bacteria.
Sulfolobus is an extremophile that is found in hot springs and thrives in acidic and sulphur-rich environments.
Methanosarcina rumen (green with red cell walls).
Methanosarcina rumen is anaerobic, and is found in places with little or no oxygen. It is a methane- producing organism that digests decaying organic matter. It is found in the rumen of a group of animals called ruminants such as cattle and sheep.
Staphylothermus marinus is an extremophile found in deep ocean hydrothermal vents, thriving on volcanic sulphur and surviving in water temperatures of up to 98°C
Halococcus salifodinae is found in water with high concentrations of salt. These high salt concentrations would be deadly to most other forms of life, and so H. salifodinae is also known as an extremophile.
Methanococcoides burtonii is an extremophile and was discovered in 1992 in Ace Lake, Antarctica, and can survive in temperatures as low as -2.5 °C.
Many archaea have been found living in extreme environments, for example at high pressures, salt concentrations or temperatures, and have been nicknamed extremophiles. Their cell wall differs in structure from that of bacteria and is thought to be more stable in extreme conditions, helping to explain why some archaea can live in many of the most hostile environments on Earth.
Examples of archaea habitats are boiling hot springs and geysers such as those found in Yellow Stone Park, USA and ice such as the Artic and Antarctic oceans which remain frozen for most of the year.