Some hyperthermophilic organisms that grow in highly acidic ( $\mathrm{pH} 2$ ) habitats belong to the two groups called

Thermophiles live in very hot places, typically from $60^{\circ}$ to $80^{\circ} \mathrm{C}$. Many thermophiles (some eubacteria and archaebacteria) are autotrophs and have metabolisms based on sulphur. Some thermophilic archaebacteria form the basis of food webs around deep-sea thermal vents, where they must withstand extreme temperature and pressures. Archaebacteria can grow in highly acidic $(\mathrm{pH}=0.7)$ and very basic $(\mathrm{pH}=11)$ environments.