1. Extremophiles!
Life living in anthropocentrically extreme environments:
Temperature
pH (Acidity or Alkalinity)
Salinity (Osmotic Stress)
Radiation
Barometric Pressure

3. Halophilic Archaea Life in hypersaline habitats.
Not just tolerant of high salt but require it for physiological function.
Need a minimum of 1.5 M NaCl (or other salt); Live in 2-7 M NaCl; where seawater is 0.7 M NaCl.
Alkaliphilic Natronobacteria
Mostly Chemoheterotrophs; depend on oxygenic photosynthetic green algea Dunaliella and anoxygenic phtosynthetic purple bacteria Ectothiorhodospira and Halorhodospira.
Few are partially photoheterotrophic at low oxygen (need ATP supplement) (Halobacterium salinarum)

4. Halobacterium Phototrophy
See Box20.1 (p 462)
Why the purple membrane?

5. Thermoplasmatales (cell wall-less; extreme acidophiles)
Thermophile as well (likes 55 ºC)
Chemoheterotroph
Ferroplasma:
Chemolithoautotroph;
Autotrophic by oxidizing Fe(II)
Acid mine drainage archaea
Picrophilus:
Most extreme acidophile (0.6 pH optimum)

6. Hyperthermophiles Thermococcales (Euryarchaeota):
Anaerobic sulfur reducing chemoheterotroph.
Flagellated motility
Temperature optimum ºC
Archaeoglobales (Euryarchaeota):
Anaerobic sulfate reducers
Temperature optimum 83 ºC

7. Cultured Crenarchaeota Hyperthermophiles
Submarine volcanic
Acidic terrestrial volcanic
Terrestrial volcanic

8. The unique archaeal morphology of Pyrodictium; disc-like cells with network of intertwined thread-like appendages.

9. Bacterial “Extremophiles”
Thermophilic chemolithoautotroph
Thermophilic chemoheterotroph
Radiation tolerance 10,000x humans.