Bacteria that live and reproduce outside (either colder or hotter) the typical temperature range of 40°F (4°C) to 140°F (60°C) that bacteria tend to be found in, on Earth. Other extremes are high pressure (e.g., at the ocean bottom), salt saturation, (e.g., the Dead Sea), pH lower than 2 (e.g., coal deposits), pH higher than 1 1 (e.g., sewage sludge).