Biological limits of temperature and pressure

Most biologists do not take into account that the greatest portion of today's biosphere is in the realm of environmental extremes, most of it being cold and under pressure. Since bacteria have the ability to adapt to environmental extremes, a close examination for the presence and/or growth of bacteria at high and low temperatures, low temperature and reduced pressure (less than 1 atm), low temperature and increased hydrostatic pressure should be made. It is also within the realm of possibility that life may have arisen in an environmental extreme on the primordial earth and then evolved over time to live under moderate temperatures and 1 atm. Microbial life has been demonstrated at temperatures slightly greater than 90°C, below 0°C, at hydrostatic pressures of 1100 atm, and possibly at cold temperatures in the atmosphere (less than 1 atm). Laboratory experiments have shown that certain enzyme reactions can occur above 100°C under hydrostatic pressure, at –26°C and at 5°C under hydrostatic pressure.Proceedings of the Fourth College Park Colloquium on Chemical Evolution:Limits of Life, University of Maryland, College Park, 18–20 October 1978.