Biological diversity is a term most often associated with large animals and plants. However, the majority of organisms are microbes and the diversity among microbes is far greater than among animals or plants. What is already known indicates that the physiological, metabolic, genetic and phylogenetic diversity of microorganisms is unparalleled by any other life form. This vast and diverse microbial world occupies every nook and cranny of the globe, from the deepest depths of the ocean to the highest mountain peaks, living in the water, soil and air that surround us, on and in the food that we eat and on and within our own bodies.

Microbes (including viruses, bacteria, fungi, protozoa and microalgae) are unseen Ethiopian natural resources that deserve greater attention. The fact that microbes are too small to be seen, does not mean they are too small to be studied and exploited or valued. They play many roles, including being the first to colonize and ameliorate the effects of naturally occurring and man-made disturbed environments (Bull, 2003).

The uniqueness of microbes and their often unpredictable nature and biosynthetic capabilities adapted to a specific set of environmental and cultural conditions, has made them likely candidates for solving particularly difficult problems facing the entire network of life on Earth. The various ways in which microbes have been used over the past five decades confirms that these organisms represent an untapped and extremely valuable resource to advance agricultural biotechnology, medical technology, human and animal health, food processing, food safety and quality, genetic engineering, environmental protection, and more effective treatment of agricultural and municipal wastes. Many of these technological advances would not have been possible using straightforward chemical and physical engineering methods, or if they were, they would not have been practically or economically feasible (National Research Council, 1999).

Very clearly, microbes have profound effects on ecosystem functions such as decomposition of organic matter, nutrient cycling and soil fertility, bioremediation of toxics and pollutants, trophic interactions that affect communal relations of living things, and both the spread and control of infectious diseases of plants, animals and humans (National Research Council, 2000).

It is well known that microbes are effectively everywhere, emerging patchily when substrates and environmental conditions are appropriate. On the other hand, microbial communities either adapt to a location or disappear, forming distinct communities that differentially respond to shifting conditions. These shifts are accompanied by changes in ecosystem functions and affect other trophic interactions, such as nutrient supply to plants, and ultimately environmental outcomes such as greenhouse gas emissions, carbon sequestration. Extremely diverse ocean and terrestrial microbial communities serve fundamentally different roles in the carbon cycle as primary photosynthetic producers of biomass in the ocean biological pump and as carbon and nutrient managers and decomposers in terrestrial systems. Microbes cycle immense volumes of carbon in the process of recycling most of earth’s biomass. They can fix CO2 by light-driven (photoautotrophy) and geochemically driven (lithoautotrophy) reactions, generate methane, produce CO2 as they decompose organic matter, precipitate carbonate minerals, and catalyze the polymerization of plant polymers into recalcitrant pools of carbon in soil. Some of the potential microbes are Emiliania huxleyi, Synechococcus sp., Prochlorococcus marinus and Thalassiosira pseudonana. Current research on the molecular processes underlying the capabilities of these microbes can lead to more-accurate climate models and strategies for carbon sequestration (U.S. Department of Energy Office of Science, 2005), nitrogen retention, and water quality that affect the provision of ecosystem services of value to humans (King, 2000; Ogunseitan, 2000; Wall et al., 2001; Bull, 2003; Pear et al., 2003).