| Type | Tolerance | Environment | Example |
|---|---|---|---|
| Halophile | High salinity | Playa lakes Marine evaporites | Great Salt Lake, Utah |
| Acidophile | High acidity | Mine drainage Water near volcanoes | Rio Tinto, Spain |
| Thermophile | High temperature | Hot springs Mid-ocean ridge vents | Yellowstone National Park |
| Anaerobe | No oxygen | Pores of wet sediments Groundwater Microbial mats Mid-ocean ridge vents | Cape Cod Bay sediments |