Diversity of Archaea III

Crenarchaeota, the most abundant archaeal phylum, inhabits diverse environments, from soils to extreme habitats like sulfuric hot springs and volcanic systems.

They adapt to these conditions through features like thermostable proteins, specialized lipids, sulfur-based respiration, and hydrogen as electron donors.

Many are obligate anaerobes that oxidize inorganic molecules for energy.

Crenarchaeota members exhibit diverse cell shapes, including filaments, irregular discs, and lobed cocci.

They are classified into three orders — Sulfolobales, Desulfurococcales, and Thermoproteales.

Sulfolobus, belonging to the order Sulfolobales, is an aerobic chemolithotroph that uses sulfur and carbon dioxide to produce energy but can also grow chemoorganotrophically.

Pyrodictium species of the order Desulfurococcales inhabit hydrothermal vents, using filament networks to stabilize their cells in high-temperature environments.

From the order Thermoproteales, Thermoproteus and Thermofilum are strict anaerobes utilizing sulfur-based respiration.

While Pyrobaculum can respire aerobically or anaerobically, using nitrate, iron, or sulfur as electron acceptors.”