Teacher's Resources

• Do the bacteria in the water make us sick?

  Only a few of them.  Bacteria are in every habitat on Earth, growing in soil, hot springs, radioactive waste, water, as well as in organic matter and the live bodies of plants and animals. Bacteria recycle nutrients, with many steps in nutrient cycles depending on these organisms, such as nitrogen fixation.

• Why don’t the bacteria die at such cold temperatures?

  Psychrophiles or cryophiles are extremophilic organisms that are capable of growth and reproduction in cold temperatures, ranging from -15°C - +10°C. Temperatures as low as -15°C are found in pockets of very salty water (brine) surrounded by sea ice. The environments they inhabit are ubiquitous on Earth, as a large fraction of our planetary surface experiences temperatures lower than 15°C. They are present in alpine and arctic soils, high-latitude and deep ocean waters, polar ice, glaciers, and snowfields. They are of particular interest to geomicrobiology, the study of microbes active in geochemical processes.