​CLASSIFICATION FIVE PHYLUMS
1. Crenarchaeota
2. Euryarchaeota
3. Korarchaeota
4. Thuamarchaeota
​5. Nanoarchaeota

​1)  CRENARCHEOTA

 • The name Crenarchaeota means “scalloped archaea.” they are often irregular or somewhat "scallop-shaped".
 •All crenarchaeotes synthesize a distinctive tetraether lipid, called crenarchaeol.

This phylum includes

• acidophiles
  
• hyperthermophiles
• hyperthermophilic sulfur-metabolizing archaea
• morphologically diverse

​Example organisms

• Sulfolobus solfataricus
  • ​It was first isolated and discovered in the Solfatara volcano 
  • lives in sulfuric, acidic hot springs (80 °C & pH of 2–4) 
•  Methanopyrus kandleri has been discovered which can survive temperatures up to 122°C.

Sulfolobus solfataricus

2)  Euryarchaeota

This Phylum of Archaea includes
Methanogens
Halophiles
Thermophilic & Sulfur-reducing archaea 

methanogens

• The methanogens are a group archaea from the euryarchaeota phylum that produce methane gas -
  • more than 2 billion tons of methane gas is released by them each year
  • one-third of the methane gas release comes from cows
• methanogens are also anaerobes -
  • The definition of an anaerobe, is that they do not need oxygen.
  • Methanogens are actually killed by oxygen gas.
• Habitat
  • Many live in mud at the bottom of lakes and swamps because it lacks oxygen
  • They are also found in the gut of some herbivores like cows or humans
  • Can be found in dead & decaying matter ​

Millions of Tons of Methane Gas is Released From the Methanogenic Archaea in the G.I. Tract of Cows Each Year!

Methanogens can also be found in dead and decaying matter ​.

halophiles

The halophiles are a group archaea from the euryarchaeota phylum that produce requires large concentrations of salt (NaCl) to survive (halo = “salt”; phil = “loving”).

• Aerobic (they require oxygen gas)
• Basophiles - (found in high pH / alkaline / basic conditions) 
• Found in places like the Great Salt Lake in Utah and the Dead Sea. 

Thermophilic & Sulfur-reducing archaea
The euryarchaeota phylum also contains a number of other extremophiles.

• Thermophiles (require hot water habitats)
• Hyperthermophiles (require extremely hot habitats)
• Thermoacidophiles (required hot acidic habitats)
• Acidophiles (require acidic environment)
• S-dependent metabolism (requires sulfur to survive)

3) Korarchaeota

• ​This phylum gets its name from the Greek word meaning "young man or woman". 
  
• They are hyperthermophiles
  
• pH is somewhat neutral (pH = about 7)
• They are found in high temperature hydrothermal environments.
  
• They were discovered in Yellowstone National Park 

Korarchaeota

4) Thuamarchaeota

• ​The archaeal phylum Thaumarchaeota gets its name from the Greek word meaning "wonder".
• The odd name for this phylum came about due to the sequencing of the C. symbiosum genome in 2008. The C. symbiosum genome was found to be so unique from the other known archaea, that a new phylum was created!
• All species belonging to this phylum discovered so far, are chemolithoautotrophic ammonia-oxidizers
  • play important roles nitrogen cycle and the carbon cycle.
  • has type I topoisomerase that was previously thought to only exist in eukaryotes.

​5) Nanoarchaeota

• The Nanoarchaeota get their name from Greek word meaning "old dwarf“.
• They are hyperthermophiles that have optimal growth at 90 C
• They ONLY grow and divide on the surface of another archaea, Ignicoccus.
• Nanoarchaeota, are the smallest living cells ever discovered measuring only 0.4 micrometers.
  
• Nanoarchaeota, also have the smallest genome of any living organism we know of, measuring only 480 kilobases.

Archaea Come is a Wider Variety of Shapes than Bacteria

 OTHER ODD STRUCTURAL FEATURES OF ARCHAEA