Table 2.

Maximum temperature limit for activity/survival of different microbial groups.

Microbial group	Upper temperature limit (°C)	Details	Reference
Bacteria (activity)	100	Geothermobacterium ferrireducens gen. nov., sp. nov., isolated from a geothermal pool in Yellowstone National Park, USA	Kashefi et al. (2002)
Archaea and methanogen (activity)	122	Methanopyrus kandleri isolated from a hydrothermal vent, Gulf of California, USA	Takai et al. (2008)
Fungi (activity)	60–62	species not identified	Tansey and Brock (1972)
Sulphate reducers (activity)	90	Archaeoglobus profundus isolated from hydrothermal systems in Guaymas, Mexico can use sulphate, thiosulphate, and sulphite as electron donors.	Burggraf et al. (1990)
Sulphate reducers (activity)	110	Observation of microbial sulphate reduction in sediments	Jørgensen et al. (1992)
Iron reducers (activity)	121	Geogemma barossii isolated from a hydrothermal vent in Puget Sound, USA	Kashefi and Lovley (2003)
Bacterial spore (survival)	180	This is a short-term survival limit for some spores within a mixed bentonite community. See notes in text for discussion about longer term survival	Miettinen et al. (2022)