Microorganisms as key links in the flow of substances and energy in ecospheres

The most energy on Earth derives from radiant energy of the sun, which is transformed into chemical and mechanical energy. Energy links species, and flows through ecosystems because changing the energy available at one part of the food chain causes changes throughout the ecosystem. Movements and transformations of elements and their compounds by biochemical activity of the ecosphere where they circulate with characteristic pathways between its abiotic and biotic parts are called biogeochemical cycles (BGCC). They include physical transformations, such as dissolution, precipitation, evaporation, and fixation, such as chemical changes, biosynthesis, biodegradation, redox reactions, and also various combinations of these changes. There are biogeochemical cycles for chemical elements, such as for carbon, hydrogen, nitrogen, oxygen, phosphorus, selenium, mercury, iron and sulfur. Microorganisms play crucial role in the BGCC’s though production, decomposition, and fixation of biogenic elements and compounds, as well as symbiotic relationships with other organisms. Due to high diversity of microorganisms, their various metabolic and biosynthetic pathways and unpredictable number of compunds with the most diverse structures as well as functions of secondary metabolites microorganisms are applied in many aspects of human life: the decomposition of pollutants and toxic wastes (biodegradation or bioremediation of domestic, agricultural, and industrial wastes), the efficient utilization of limited natural resources (bioleaching) and transformations of chemical substances that can be used by other organisms