Because microorganisms are small, they are least known, and this gap in knowledge is particularly apparent for bacteria and other small organisms. For bacteria there may be 300,000 to 1 million species on earth yet only 3,100 bacteria are described in Bergey's Manual, the treatise of described bacteria. Similarly low fractions of microorganisms have been cultured from fresh water and ocean environments. Hence, most microbes remain to be discovered. Focusing on microbial diversity is timely.
Diverse microorganisms are essential to a sustainable biosphere.
They are able to recycle nutrients, produce and consume gases that affect global climate, destroy pollutants, treat our wastes, and they can be used for biological control of plant and animal pests. The study of microbial diversity is also important to solve new and emerging disease problems and to advance biotechnology. New technologies, particularly in nucleic acid analysis, computer science, analytical chemistry, and habitat sampling and characterization place the study of microbial diversity on the cutting edge of science. Humans over the ages have been highly successful in applying processes carried out by microorganisms to solve problems in agriculture, food production, human health, environmental quality, and industry. Recently developed technologies in molecular biology and genetics offer great promise for new opportunities to develop the potential of microbial diversity.