Extremophiles: the organisms thriving in environments where most organisms do not exist

In wastewater and bioremediation, we usually deal with mesophilic environments. Mesophilic being defined as:

• Temperature 10 - 40 Deg C
• pH 6.0 - 8.5
• Salinity 0 - 33,000 ppm

When we move outside the above environments, the bacteria begins to change. For example, as temperatures increase over 43 Deg C, the bacteria populations change toward higher temperature mesophilic and finally to thermophilic organisms. Just how extreme can bacteria go? In the case of archaeal organisms it can get very extreme.

A recent paper found a new type of archaea living in a rift zone volcano with temperatures between 90 - 109 Deg C and a pH of 0. I don't think we would see this organism in most wastewater facilities, but it is a good read on life at the extremes.

https://www.nature.com/articles/s41598-019-44440-8