The first and most common bacteria would be the anaerobic bacteria, Obligate Anaerobes. They are capable of living in places void of O2 and most will die in the presence of oxygen. Some agile bacteria are Facultative Anaerobes. These are able to live both in and out of an oxygen laden atmosphere but they are rare microbes. Clostridium, for example, is one bacterial genes that does not need oxygen to survive. Everyone’s smelled anaerobic decomposition inside the refrigerator on occasions. So to, we have all smelled the offensive odor of this culprit coming from an old garbage can. Byproducts of their anaerobic decay involve hydrogen sulfide which smells like rotten eggs, butyric acid which smells like vomit, ammonia which will set our nostrils reeling, and vinegar. Anaerobic conditions foster pathogenic bacteria and kill off beneficial aerobic bacteria.
The second bacteria type and the most important for live organic horticulture, is the aerobic bacteria, or Obligate Aerobes. Though respiration is crucial to life, the precise function that oxygen plays to maintain life is not readily understood. Essentially, in a microorganism that is capable of using it, O2 enables food compounds to be totally digested. This ensures that every possible amount of energy will be used for maintaining the cell. So the aerobic bacteria have the advantage of metabolic efficiency. Aerobic bacteria can create twenty times more energy, with the equivalent amount of organic compounds, than anaerobic bacteria. What is more, aerobic bacteria aren’t generally known to produce horrible odors. One bacteria in the order of Actinomycetales, genus Streptomyces called actinomycetes, generate enzymes with volatile compounds which gives earth a fresh, clean smell. This is the good quality soil we smell when we instinctively hold a fist full of substrate up to our nose. Interesting how harmonious bacteria agree with us instinctually. Life is good! Good life is king. Thank God.