Prokaryotic life has dominated most of the evolutionary history of our planet, evolving to occupy virtually all available environmental niches. Extremophiles, especially those thriving under multiple extremes, represent a key area of research for multiple disciplines, spanning from the study of adaptations to harsh conditions, to the biogeochemical cycling of elements. Extremophile research also has implications for origin of life studies and the search for life on other planetary and celestial bodies. In this article, we will review the current state of knowledge for the biospace in which life operates on Earth and will discuss it in a planetary context, highlighting knowledge gaps and areas of opportunity.

Fecal transplants are increasingly utilized for treatment of recurrent infections (i.e., Clostridium difficile) in the human gut and as a general research tool for gain-of-function experiments (i.e., gavage of fecal pellets) in animal models. Changes observed in the recipient's biology are routinely attributed to bacterial cells in the donor feces (~1011 per gram of human wet stool). Here, we examine the literature and summarize findings on the composition of fecal matter in order to raise cautiously the profile of its multipart nature. In addition to viable bacteria, which may make up a small fraction of total fecal matter, other components in unprocessed human feces include colonocytes (~107 per gram of wet stool), archaea (~108 per gram of wet stool), viruses (~108 per gram of wet stool), fungi (~106 per gram of wet stool), protists, and metabolites. Thus, while speculative at this point and contingent on the transplant procedure and study system, nonbacterial matter could contribute to changes in the recipient's biology. There is a cautious need for continued reductionism to separate out the effects and interactions of each component.

Introduction 4 Background 7 Site summaries 40 Preliminary scientific assessment 45 References

Prokaryotic life has dominated most of the evolutionary history of our planet, evolving tooccupy virtually all available environmental niches. Extremophiles, especially those thrivingunder multiple extremes, represent a key area of research for multiple disciplines, spanningfrom the study of adaptations to harsh conditions, to the biogeochemical cycling of elements.Extremophile research also has implications for origin of life studies and the search for life onother planetary and celestial bodies. In this article, we will review the current state ofknowledge for the biospace in which life operates on Earth and will discuss it in a planetarycontext, highlighting knowledge gaps and areas of opportunity.

The best precaution is to ensure that the operating temperature is constant during measurements, and preferably cool, and that sensor and samples have time to reach an equilibrium temperature. This may be more difficult when operating in the field. Wet ConditionsCaution: These instruments are protected against the ingress of moisture but operation in very wet conditions should be avoided.Note: Some sensors can be operated while submerged in water: see product brochure for further information. Noise and Interference CheckCaution: These instruments should not be operated close to high power radio transmitters, heavy electrical machinery, computers, or other electrical or magnetic equipment. Note:The unit is unlikely to be affected by interference from other equipment in the normal operating environment. However, by their nature the sensors are susceptible to electromagnetic interference and operation close to a radio frequency source with a frequency close to the operating frequency of the sensor should be avoided. It is important to position the sensor to minimise interference and obtain the best performance.Select the normal sensitivity, x1.0 range. With no sample present, first press the 'Z' button and then select continuous measurements on the 'M' toggle switch. If fluctuations of greater than ±1 least significant digit per reading appear on the display then external electrical noise should be suspected. In this case the only solution is to re-site the equipment.Before using the laboratory sensors, first check the selected area for freedom from large ferrous objects by moving the sensor and watching for any changes on the display.