Microscopic organisms survive at such extreme heights, depths and temperatures that the biosphere can be construed even more expansive. Culturable microbes have been found in the Earth's upper atmosphere as high as 41 km, even though it is unlikely they have appreciable metabolism in that realm, where temperature and pressure are extremely low and ultraviolet radiation high. More likely these microbes were transported to the upper atmosphere by vertical convection. Barophilic marine microbes occur at depths greater than ten km in the Marianas Trench; moreover, thermophilic microbes have been extracted from cores drilled more than five km into solid crust in Sweden, from rock formations as hot as 650C. The record temperature for microbial occurrence is 1220C for a strain of Methanopyrus kandleri; moreover, it is thought that the depth limit of living organisms is governed by temperature rather than depth.